Phytoremediation of ionic and methylmercury pollution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meagher, Richard B.

Our long-term objective is to enable highly productive plant species to extract, resist, detoxify, and/or sequester toxic organic and heavy metal pollutants (Meagher, 2000) applying scientific strategies and technologies from a rapidly developing field called phytoremediation. The phytoremediation of toxic elemental and organic pollutants requires the use relatively different approaches (Meagher, 2000). Our current specific objectives are to use transgenic plants to control the chemical species, electrochemical state, and aboveground binding of mercury to (a) prevent methylmercury from entering the food-chain, (b) remove mercury from polluted sites, and (c) hyperaccumulate mercury in aboveground tissues for later harvest. Various parts ofmore » this strategy are being critically tested by examining different genes in model plants and field species and comparing the results to control plants as we recently reviewed (Meagher et al., 2000; Rugh et al., 2000). A positive spin-off from this work on mercury has been a strategy for the phytoremediation of arsenic (Dhankher et al., 2002) and cadmium.« less

Situ formation of apatite for sequestering radionuclides and heavy metals

DOEpatents

Moore, Robert C.

2003-07-15

Methods for in situ formation in soil of a permeable reactive barrier or zone comprising a phosphate precipitate, such as apatite or hydroxyapatite, which is capable of selectively trapping and removing radionuclides and heavy metal contaminants from the soil, while allowing water or other compounds to pass through. A preparation of a phosphate reagent and a chelated calcium reagent is mixed aboveground and injected into the soil. Subsequently, the chelated calcium reagent biodegrades and slowly releases free calcium. The free calcium reacts with the phosphate reagent to form a phosphate precipitate. Under the proper chemical conditions, apatite or hydroxyapatite can form. Radionuclide and heavy metal contaminants, including lead, strontium, lanthanides, and uranium are then selectively sequestered by sorbing them onto the phosphate precipitate. A reducing agent can be added for reduction and selective sequestration of technetium or selenium contaminants.

USE OF POWDERED COCONUT CHARCOAL AS A TOXICITY IDENTIFICATION AND EVALUATION MANIPULATION FOR ORGANIC TOXICANTS IN MARINE SEDIMENTS

EPA Science Inventory

We report on a procedure using powdered coconut charcoal to sequester organic contaminants and reduce toxicity in sediments as part of a series of toxicity identification and evaluation (TIE) methods. Powdered coconut charcoal (PCC) was effective in reducing the toxicity of endos...

Stage-dependency of apoptosis and the blood-testis barrier in the dogfish shark (Squalus acanthias): cadmium-induced changes as assessed by vital fluorescence techniques.

PubMed

McClusky, Leon M

2006-09-01

Naturally occurring heavy metals and synthetic compounds are potentially harmful for testicular function but evidence linking heavy metal exposure to reduced semen parameters is inconclusive. Elucidation of the exact stage at which the toxicant interferes with spermatogenesis is difficult because the various germ cell stages may have different sensitivities to any given toxicant, germ cell development is influenced by supporting testicular somatic cells and the presence of inter-Sertoli cell tight junctions create a blood-testis barrier, sequestering meiotic and postmeiotic germ cells in a special microenvironment. Sharks such as Squalus acanthias provide a suitable model for studying aspects of vertebrate spermatogenosis because of their unique features: spermatogenesis takes place within spermatocysts and relies mainly on Sertoli cells for somatic cell support; spermatocysts are linearly arranged in a maturational order across the diameter of the elongated testis; spermatocysts containing germ cells at different stages of development are topographically separated, resulting in visible zonation in testicular cross sections. We have used the vital dye acridine orange and a novel fluorescence staining technique to study this model to determine (1) the efficacy of these methods in assays of apoptosis and blood-testis barrier function, (2) the sensitivity of the various spermatogonial generations in Squalus to cadmium (as an illustrative spermatotoxicant) and (3) the way that cadmium might affect more mature spermatogenic stages and other physiological processes in the testis. Our results show that cadmium targets early spermatogenic stages, where it specifically activates a cell death program in susceptible (mature) spermatogonial clones, and negatively affects blood-testis barrier function. Since other parameters are relatively unaffected by cadmium, the effects of this toxicant on apoptosis are presumably process-specific and not attributable to general toxicity.

Active foraging for toxic prey during gestation in a snake with maternal provisioning of sequestered chemical defences

PubMed Central

Kojima, Yosuke; Mori, Akira

2015-01-01

Many animals sequester dietary defensive compounds and incorporate them into the offspring, which protects the young against predation. One possible but poorly investigated question is whether females of such species actively prey upon toxic diets. The snake Rhabdophis tigrinus sequesters defensive steroids from toads consumed as prey; it also feeds on other amphibians. Females produce chemically armed offspring in direct proportion to their own level of toad-derived toxins by provisioning the toxins to their eggs. Our field observations of movements and stomach contents of radio-tracked R. tigrinus showed that gravid snakes preyed upon toads by actively foraging in the habitat of toads, even though toads were a scarce resource and toad-searching may incur potential costs. Our Y-maze experiments demonstrated that gravid females were more likely to trail the chemical cues of toads than were males or non-gravid females. These results showed behavioural switching in females and active foraging for scarce, toxic prey during gestation. Because exploitation of toads by gravid females results in their offspring being more richly endowed with prey-derived toxins, active foraging for toxic prey is expected to be an adaptive antipredator trait, which may enhance chemical defence in offspring. PMID:25392472

Active foraging for toxic prey during gestation in a snake with maternal provisioning of sequestered chemical defences.

PubMed

Kojima, Yosuke; Mori, Akira

2015-01-07

Many animals sequester dietary defensive compounds and incorporate them into the offspring, which protects the young against predation. One possible but poorly investigated question is whether females of such species actively prey upon toxic diets. The snake Rhabdophis tigrinus sequesters defensive steroids from toads consumed as prey; it also feeds on other amphibians. Females produce chemically armed offspring in direct proportion to their own level of toad-derived toxins by provisioning the toxins to their eggs. Our field observations of movements and stomach contents of radio-tracked R. tigrinus showed that gravid snakes preyed upon toads by actively foraging in the habitat of toads, even though toads were a scarce resource and toad-searching may incur potential costs. Our Y-maze experiments demonstrated that gravid females were more likely to trail the chemical cues of toads than were males or non-gravid females. These results showed behavioural switching in females and active foraging for scarce, toxic prey during gestation. Because exploitation of toads by gravid females results in their offspring being more richly endowed with prey-derived toxins, active foraging for toxic prey is expected to be an adaptive antipredator trait, which may enhance chemical defence in offspring. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Bacterial Exopolysaccharide mediated heavy metal removal: A Review on biosynthesis, mechanism and remediation strategies.

PubMed

Gupta, Pratima; Diwan, Batul

2017-03-01

Heavy metal contamination has been recognized as a major public health risk, particularly in developing countries and their toxicological manifestations are well known. Conventional remediation strategies are either expensive or they generate toxic by-products, which adversely affect the environment. Therefore, necessity for an environmentally safe strategy motivates interest towards biological techniques. One of such most profoundly driven approach in recent times is biosorption through microbial biomass and their products. Extracellular polymeric substances are such complex blend of high molecular weight microbial (prokaryotic and eukaryotic) biopolymers. They are mainly composed of proteins, polysaccharides, uronic acids, humic substances, lipids etc. One of its essential constituent is the exopolysaccharide (EPS) released out of self defense against harsh conditions of starvation, pH and temperature, hence it displays exemplary physiological, rheological and physio-chemical properties. Its net anionic makeup allows the biopolymer to effectively sequester positively charged heavy metal ions. The polysaccharide has been expounded deeply in this article with reference to its biosynthesis and emphasizes heavy metal sorption abilities of polymer in terms of mechanism of action and remediation. It reports current investigation and strategic advancements in dealing bacterial cells and their EPS in diverse forms - mixed culture EPS, single cell EPS, live, dead or immobilized EPS. A significant scrutiny is also involved highlighting the existing challenges that still lie in the path of commercialization. The article enlightens the potential of EPS to bring about bio-detoxification of heavy metal contaminated terrestrial and aquatic systems in highly sustainable, economic and eco-friendly manner.

Milkweed butterfly resistance to plant toxins is linked to sequestration, not coping with a toxic diet.

PubMed

Petschenka, Georg; Agrawal, Anurag A

2015-11-07

Insect resistance to plant toxins is widely assumed to have evolved in response to using defended plants as a dietary resource. We tested this hypothesis in the milkweed butterflies (Danaini) which have progressively evolved higher levels of resistance to cardenolide toxins based on amino acid substitutions of their cellular sodium-potassium pump (Na(+)/K(+)-ATPase). Using chemical, physiological and caterpillar growth assays on diverse milkweeds (Asclepias spp.) and isolated cardenolides, we show that resistant Na(+)/K(+)-ATPases are not necessary to cope with dietary cardenolides. By contrast, sequestration of cardenolides in the body (as a defence against predators) is associated with the three levels of Na(+)/K(+)-ATPase resistance. To estimate the potential physiological burden of cardenolide sequestration without Na(+)/K(+)-ATPase adaptations, we applied haemolymph of sequestering species on isolated Na(+)/K(+)-ATPase of sequestering and non-sequestering species. Haemolymph cardenolides dramatically impair non-adapted Na(+)/K(+)-ATPase, but had systematically reduced effects on Na(+)/K(+)-ATPase of sequestering species. Our data indicate that major adaptations to plant toxins may be evolutionarily linked to sequestration, and may not necessarily be a means to eat toxic plants. Na(+)/K(+)-ATPase adaptations thus were a potential mechanism through which predators spurred the coevolutionary arms race between plants and insects. © 2015 The Author(s).

Milkweed butterfly resistance to plant toxins is linked to sequestration, not coping with a toxic diet

PubMed Central

Petschenka, Georg; Agrawal, Anurag A.

2015-01-01

Insect resistance to plant toxins is widely assumed to have evolved in response to using defended plants as a dietary resource. We tested this hypothesis in the milkweed butterflies (Danaini) which have progressively evolved higher levels of resistance to cardenolide toxins based on amino acid substitutions of their cellular sodium–potassium pump (Na+/K+-ATPase). Using chemical, physiological and caterpillar growth assays on diverse milkweeds (Asclepias spp.) and isolated cardenolides, we show that resistant Na+/K+-ATPases are not necessary to cope with dietary cardenolides. By contrast, sequestration of cardenolides in the body (as a defence against predators) is associated with the three levels of Na+/K+-ATPase resistance. To estimate the potential physiological burden of cardenolide sequestration without Na+/K+-ATPase adaptations, we applied haemolymph of sequestering species on isolated Na+/K+-ATPase of sequestering and non-sequestering species. Haemolymph cardenolides dramatically impair non-adapted Na+/K+-ATPase, but had systematically reduced effects on Na+/K+-ATPase of sequestering species. Our data indicate that major adaptations to plant toxins may be evolutionarily linked to sequestration, and may not necessarily be a means to eat toxic plants. Na+/K+-ATPase adaptations thus were a potential mechanism through which predators spurred the coevolutionary arms race between plants and insects. PMID:26538594

Phytoremediation of ionic and methylmercury pollution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meagher, Richard B.

2010-04-28

Our long-term goal is to enable highly productive plant species to extract, resist, detoxify, and sequester the toxic elemental pollutants, like the heavy metal mercury. Our current working hypothesis is that transgenic plants controlling the transport, chemical speciation, electrochemical state. volatilization, and aboveground binding of mercury will: a) tolerate mercury and grow rapidly in mercury contaminated environments; b) prevent methylmercury from entering the food chain; c) remove mercury from polluted soil and water; and d) hyperaccumulate mercury in aboveground tissues for later harvest. Progress toward these specific aims is reported: to increase the transport of mercury into roots and tomore » aboveground vegetative organs; to increase biochemical sinks and storage for mercury in leaves; to increase leaf cell vacuolar storage of mercury; and to demonstrate that several stacked transgenes, when functioning in concert, enhance mercury resistance and hyperaccumulation to high levels.« less

Pharmacokinetic Models for the Elimination of Drinking Water Contaminants from the Body,

DTIC Science & Technology

1990-03-01

that are sequestered in the bones (lead, barium), in certain soft tissues such as the kidney ( cadmium ), and in the adipose tissue (DDT...slow" component (sequestered in 3 bone or in adipose tissue ). Finally, much more attention must be given to differences among I individuals and among...lead from bone, effectively reducing the half-life. Fasting or starvation can mobilize toxicants 3 stored in adipose tissue . Competition for enzyme

In Situ Formation of Calcium Apatite in Soil for Sequestering Contaminants in Soil and Groundwater

ScienceCinema

Moore, Robert; Szecsody, Jim; Thompson, Mike

2018-01-16

A new method for in situ formation of a calcium apatite permeable reactive barrier that is a groundbreaking technology for containing radioactive/heavy metal contaminants threatening groundwater supplies.

In Situ Formation of Calcium Apatite in Soil for Sequestering Contaminants in Soil and Groundwater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, Robert; Szecsody, Jim; Thompson, Mike

2015-10-20

A new method for in situ formation of a calcium apatite permeable reactive barrier that is a groundbreaking technology for containing radioactive/heavy metal contaminants threatening groundwater supplies.

Inert Reassessment Document for Ethylenediaminetetracetric acid (EDTA)

EPA Pesticide Factsheets

EDTA is a chelating agent. Its ability to bind heavy metal ions can be used to sequester these trace metals. However, trace amounts of various metals are necessary for the proper functioning of the body.

USE OF ULVA LACTUCA TO DISTINGUISH PH DEPENDENT TOXICANTS IN MARINE WATERS AND SEDIMENTS

EPA Science Inventory

Ulva lactuca (sea lettuce) is a cosmopolitan marine attached green seaweed capable of sequestering high environmental levels of ammonia. Ammonia can be acutely toxic to marine organisms and is often found in dredged sediments from highly industrial areas or from areas with high c...

Hazard assessment of a simulated oil spill on intertidal areas of the St. Lawrence River with SPMD-TOX

USGS Publications Warehouse

Johnson, B. Thomas; Petty, J.D.; Huckins, J.N.; Lee, Kenneth; Gauthier, J.

2004-01-01

Phytoremediation in a simulated crude oil spill was studied with a “minimalistic” approach. The SPMD-TOX paradigm—a miniature passive sorptive device to collect and concentrate chemicals and microscale tests to detect toxicity—was used to monitor over time the bioavailability and potential toxicity of an oil spill. A simulated crude oil spill was initiated on an intertidal freshwater grass-wetland along the St. Lawrence River southwest of Quebec City, Quebec, Canada. Several phytoremediation treatments were investigated; to dissipate and ameliorate the spill, treatments included nutrient amendments with inorganic nitrogen sources (ammonium nitrate and sodium nitrate) and phosphate (super triple phosphate) with and without cut plants, with natural attenuation (no phytoremedial treatment) as a control. Sequestered oil residues were bioavailable in all oil-treated plots in Weeks 1 and 2. Interestingly, the samples were colored and fluoresced under ultraviolet light. In addition, microscale tests showed that sequestered residues were acutely toxic and genotoxic, as well as that they induced hepatic P450enzymes. Analysis of these data suggested that polycyclic aromatic hydrocarbons were among the bioavailable residues sequestered. In addition, these findings suggested that the toxic bioavailable fractions of the oil spill and degradation products dissipated rapidly over time because after the second week the water column contained no oil or detectable degradation products in this riverine intertidal wetland. SPMD-TOX revealed no evidence of bioavailable oil products in Weeks 4, 6, 8, and 12. All phytoremediation efforts appeared to be ineffective in changing either the dissipation rate or the ability to ameliorate the oil toxicity. SPMD-TOX analysis of the water columns from these riverine experimental plots profiled the occurrence, dissipation, and influence of phytoremediation on the bioavailability and toxicity of oil products (parent or degradation products).

The multiple strategies of an insect herbivore to overcome plant cyanogenic glucoside defence.

PubMed

Pentzold, Stefan; Zagrobelny, Mika; Roelsgaard, Pernille Sølvhøj; Møller, Birger Lindberg; Bak, Søren

2014-01-01

Cyanogenic glucosides (CNglcs) are widespread plant defence compounds that release toxic hydrogen cyanide by plant β-glucosidase activity after tissue damage. Specialised insect herbivores have evolved counter strategies and some sequester CNglcs, but the underlying mechanisms to keep CNglcs intact during feeding and digestion are unknown. We show that CNglc-sequestering Zygaena filipendulae larvae combine behavioural, morphological, physiological and biochemical strategies at different time points during feeding and digestion to avoid toxic hydrolysis of the CNglcs present in their Lotus food plant, i.e. cyanogenesis. We found that a high feeding rate limits the time for plant β-glucosidases to hydrolyse CNglcs. Larvae performed leaf-snipping, a minimal disruptive feeding mode that prevents mixing of plant β-glucosidases and CNglcs. Saliva extracts did not inhibit plant cyanogenesis. However, a highly alkaline midgut lumen inhibited the activity of ingested plant β-glucosidases significantly. Moreover, insect β-glucosidases from the saliva and gut tissue did not hydrolyse the CNglcs present in Lotus. The strategies disclosed may also be used by other insect species to overcome CNglc-based plant defence and to sequester these compounds intact.

Poor sequestration of toxic host plant cardenolides and their rapid loss in the milkweed butterfly Danaus chrysippus (Lepidoptera: Nymphalidae: Danainae: Danaini).

PubMed

Mebs, Dietrich; Wunder, Cora; Toennes, Stefan W

2017-06-01

Butterflies of the genus Danaus are known to sequester toxic cardenolides from milkweed host plants (Apocynaceae). In particular, Danaus plexippus efficiently sequesters and stores these compounds, whereas D. chrysippus, is considered to poorly sequester cardenolides. To estimate its sequestration capability compared with that of D. plexippus, larvae of both species were jointly reared on Asclepias curassavica and the major cardenolides of the host plant, calotropin and calactin, were analyzed in adults sampled at different time intervals after eclosion. Both cardenolides were detected in body and wings of D. plexippus. Whereas the calotropin-concentration remained constant over a period of 24 days, that of calactin steadily decreased. In the body, but not in the wings of D. chrysippus, calactin only was detected in low amounts, which was then almost completely lost during the following 8 days after eclosion, suggesting that in contrast to D. plexippus, cardenolides seem to be less important for that butterfly's defence against predators. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mercerized mesoporous date pit activated carbon—A novel adsorbent to sequester potentially toxic divalent heavy metals from water

PubMed Central

Aldawsari, Abdullah; Hameed, B. H.; Alqadami, Ayoub Abdullah; Siddiqui, Masoom Raza; Alothman, Zeid Abdullah; Ahmed, A. Yacine Badjah Hadj

2017-01-01

A substantive approach converting waste date pits to mercerized mesoporous date pit activated carbon (DPAC) and utilizing it in the removal of Cd(II), Cu(II), Pb(II), and Zn(II) was reported. In general, rapid heavy metals adsorption kinetics for Co range: 25–100 mg/L was observed, accomplishing 77–97% adsorption within 15 min, finally, attaining equilibrium in 360 min. Linear and non-linear isotherm studies revealed Langmuir model applicability for Cd(II) and Pb(II) adsorption, while Freundlich model was fitted to Zn(II) and Cu(II) adsorption. Maximum monolayer adsorption capacities (qm) for Cd(II), Pb(II), Cu(II), and Zn(II) obtained by non-linear isotherm model at 298 K were 212.1, 133.5, 194.4, and 111 mg/g, respectively. Kinetics modeling parameters showed the applicability of pseudo-second-order model. The activation energy (Ea) magnitude revealed physical nature of adsorption. Maximum elution of Cu(II) (81.6%), Zn(II) (70.1%), Pb(II) (96%), and Cd(II) (78.2%) were observed with 0.1 M HCl. Thermogravimetric analysis of DPAC showed a total weight loss (in two-stages) of 28.3%. Infra-red spectral analysis showed the presence of carboxyl and hydroxyl groups over DPAC surface. The peaks at 820, 825, 845 and 885 cm-1 attributed to Zn–O, Pb–O, Cd–O, and Cu–O appeared on heavy metals saturated DPAC, confirmed their binding on DPAC during the adsorption. PMID:28910368

Mercerized mesoporous date pit activated carbon-A novel adsorbent to sequester potentially toxic divalent heavy metals from water.

PubMed

Aldawsari, Abdullah; Khan, Moonis Ali; Hameed, B H; Alqadami, Ayoub Abdullah; Siddiqui, Masoom Raza; Alothman, Zeid Abdullah; Ahmed, A Yacine Badjah Hadj

2017-01-01

A substantive approach converting waste date pits to mercerized mesoporous date pit activated carbon (DPAC) and utilizing it in the removal of Cd(II), Cu(II), Pb(II), and Zn(II) was reported. In general, rapid heavy metals adsorption kinetics for Co range: 25-100 mg/L was observed, accomplishing 77-97% adsorption within 15 min, finally, attaining equilibrium in 360 min. Linear and non-linear isotherm studies revealed Langmuir model applicability for Cd(II) and Pb(II) adsorption, while Freundlich model was fitted to Zn(II) and Cu(II) adsorption. Maximum monolayer adsorption capacities (qm) for Cd(II), Pb(II), Cu(II), and Zn(II) obtained by non-linear isotherm model at 298 K were 212.1, 133.5, 194.4, and 111 mg/g, respectively. Kinetics modeling parameters showed the applicability of pseudo-second-order model. The activation energy (Ea) magnitude revealed physical nature of adsorption. Maximum elution of Cu(II) (81.6%), Zn(II) (70.1%), Pb(II) (96%), and Cd(II) (78.2%) were observed with 0.1 M HCl. Thermogravimetric analysis of DPAC showed a total weight loss (in two-stages) of 28.3%. Infra-red spectral analysis showed the presence of carboxyl and hydroxyl groups over DPAC surface. The peaks at 820, 825, 845 and 885 cm-1 attributed to Zn-O, Pb-O, Cd-O, and Cu-O appeared on heavy metals saturated DPAC, confirmed their binding on DPAC during the adsorption.

Unexpected Interactions of the Cyanobacterial Metallothionein SmtA with Uranium.

PubMed

Acharya, Celin; Blindauer, Claudia A

2016-02-15

Molecules for remediating or recovering uranium from contaminated environmental resources are of high current interest, with protein-based ligands coming into focus recently. Metallothioneins either bind or redox-silence a range of heavy metals, conferring protection against metal stress in many organisms. Here, we report that the cyanobacterial metallothionein SmtA competes with carbonate for uranyl binding, leading to formation of heterometallic (UO2)(n)Zn4SmtA species, without thiol oxidation, zinc loss, or compromising secondary or tertiary structure of SmtA. In turn, only metalated and folded SmtA species were found to be capable of uranyl binding. (1)H NMR studies and molecular modeling identified Glu34/Asp38 and Glu12/C-terminus as likely adventitious, but surprisingly strong, bidentate binding sites. While it is unlikely that these interactions correspond to an evolved biological function of this metallothionein, their occurrence may offer new possibilities for designing novel multipurpose bacterial metallothioneins with dual ability to sequester both soft metal ions including Cu(+), Zn(2+), Cd(2+), Hg(2+), and Pb(2+) and hard, high-oxidation state heavy metals such as U(VI). The concomitant protection from the chemical toxicity of uranium may be valuable for the development of bacterial strains for bio-remediation.

Arabidopsis and the Genetic Potential for the Phytoremediation of Toxic Elemental and Organic Pollutants

PubMed Central

Cobbett, Christopher S.; Meagher, Richard B.

2002-01-01

In a process called phytoremediation, plants can be used to extract, detoxify, and/or sequester toxic pollutants from soil, water, and air. Phytoremediation may become an essential tool in cleaning the environment and reducing human and animal exposure to potential carcinogens and other toxins. Arabidopsis has provided useful information about the genetic, physiological, and biochemical mechanisms behind phytoremediation, and it is an excellent model genetic organism to test foreign gene expression. This review focuses on Arabidopsis studies concerning: 1) the remediation of elemental pollutants; 2) the remediation of organic pollutants; and 3) the phytoremediation genome. Elemental pollutants include heavy metals and metalloids (e.g., mercury, lead, cadmium, arsenic) that are immutable. The general goal of phytoremediation is to extract, detoxify, and hyperaccumulate elemental pollutants in above-ground plant tissues for later harvest. A few dozen Arabidopsis genes and proteins that play direct roles in the remediation of elemental pollutants are discussed. Organic pollutants include toxic chemicals such as benzene, benzo(a)pyrene, polychlorinated biphenyls, trichloroethylene, trinitrotoluene, and dichlorodiphenyltrichloroethane. Phytoremediation of organic pollutants is focused on their complete mineralization to harmless products, however, less is known about the potential of plants to act on complex organic chemicals. A preliminary survey of the Arabidopsis genome suggests that as many as 700 genes encode proteins that have the capacity to act directly on environmental pollutants or could be modified to do so. The potential of the phytoremediation proteome to be used to reduce human exposure to toxic pollutants appears to be enormous and untapped. PMID:22303204

Bioassessment of heavy metal toxicity and enhancement of heavy metal removal by sulfate-reducing bacteria in the presence of zero valent iron.

PubMed

Guo, Jing; Kang, Yong; Feng, Ying

2017-12-01

A simple and valid toxicity evaluation of Zn 2+ , Mn 2+ and Cr 6+ on sulfate-reducing bacteria (SRB) and heavy metal removal were investigated using the SRB system and SRB+Fe 0 system. The heavy metal toxicity coefficient (β) and the heavy metal concentration resulting in 50% inhibition of sulfate reduction (I) from a modeling process were proposed to evaluate the heavy metal toxicity and nonlinear regression was applied to search for evaluation indices β and I. The heavy metal toxicity order was Cr 6+  > Mn 2+  > Zn 2+ . Compared with the SRB system, the SRB+Fe 0 system exhibited a better capability for sulfate reduction and heavy metal removal. The heavy metal removal was above 99% in the SRB+Fe 0 system, except for Mn 2+ . The energy-dispersive spectroscopy (EDS) analysis showed that the precipitates were removed primarily as sulfide for Zn 2+ and hydroxide for Mn 2+ and Cr 6+ .The method of evaluating the heavy metal toxicity on SRB was of great significance to understand the fundamentals of the heavy metal toxicity and inhibition effects on the microorganism and regulate the process of microbial sulfate reduction. Copyright © 2017 Elsevier Ltd. All rights reserved.

Arsenic tolerance in Arabidopsis is mediated by two ABCC-type phytochelatin transporters

PubMed Central

Song, Won-Yong; Park, Jiyoung; Mendoza-Cózatl, David G.; Suter-Grotemeyer, Marianne; Shim, Donghwan; Hörtensteiner, Stefan; Geisler, Markus; Weder, Barbara; Rea, Philip A.; Rentsch, Doris; Schroeder, Julian I.; Lee, Youngsook; Martinoia, Enrico

2010-01-01

Arsenic is an extremely toxic metalloid causing serious health problems. In Southeast Asia, aquifers providing drinking and agricultural water for tens of millions of people are contaminated with arsenic. To reduce nutritional arsenic intake through the consumption of contaminated plants, identification of the mechanisms for arsenic accumulation and detoxification in plants is a prerequisite. Phytochelatins (PCs) are glutathione-derived peptides that chelate heavy metals and metalloids such as arsenic, thereby functioning as the first step in their detoxification. Plant vacuoles act as final detoxification stores for heavy metals and arsenic. The essential PC–metal(loid) transporters that sequester toxic metal(loid)s in plant vacuoles have long been sought but remain unidentified in plants. Here we show that in the absence of two ABCC-type transporters, AtABCC1 and AtABCC2, Arabidopsis thaliana is extremely sensitive to arsenic and arsenic-based herbicides. Heterologous expression of these ABCC transporters in phytochelatin-producing Saccharomyces cerevisiae enhanced arsenic tolerance and accumulation. Furthermore, membrane vesicles isolated from these yeasts exhibited a pronounced arsenite [As(III)]–PC2 transport activity. Vacuoles isolated from atabcc1 atabcc2 double knockout plants exhibited a very low residual As(III)–PC2 transport activity, and interestingly, less PC was produced in mutant plants when exposed to arsenic. Overexpression of AtPCS1 and AtABCC1 resulted in plants exhibiting increased arsenic tolerance. Our findings demonstrate that AtABCC1 and AtABCC2 are the long-sought and major vacuolar PC transporters. Modulation of vacuolar PC transporters in other plants may allow engineering of plants suited either for phytoremediation or reduced accumulation of arsenic in edible organs. PMID:21078981

Biochar and soil properties affecting microbial transport through biochar-amended soils

USDA-ARS?s Scientific Manuscript database

The incorporation of biochar into soils has been proposed as a means to sequester carbon from the atmosphere. An added environmental benefit is that biochar has also been shown to increase soil retention of nutrients, heavy metals, and pesticides. We have recently conducted a series of experiments t...

Inactivation of E.coli 0157:H7 in cultivable soil by fast and slow pyrolysis-generated biochars

USDA-ARS?s Scientific Manuscript database

Biochar is a byproduct of incomplete combustion of organic matter, producing a fine, grainy, highly porous material. Benefits of biochar production include generation of bio-fuels, useful soil amendments for fertilizing crops, binding heavy metals, sequestering environmental biocarbon, and reducing...

Water Utility Lime Sludge Reuse – An Environmental Sorbent for Power Utilities

EPA Science Inventory

Lime sludge can be used as an environmental sorbent to remove sulfur dioxide (SO2) and acid gases, by the ultra-fine CaCO3 particles, and to sequester mercury and other heavy metals, by the Natural Organic Matter and residual activated carbon. The laboratory experimental set up ...

Suppression of polyglutamine toxicity by a Drosophila homolog of myeloid leukemia factor 1.

PubMed

Kazemi-Esfarjani, Parsa; Benzer, Seymour

2002-10-01

The toxicity of an abnormally long polyglutamine [poly(Q)] tract within specific proteins is the molecular lesion shared by Huntington's disease (HD) and several other hereditary neurodegenerative disorders. By a genetic screen in Drosophila, devised to uncover genes that suppress poly(Q) toxicity, we discovered a Drosophila homolog of human myeloid leukemia factor 1 (MLF1). Expression of the Drosophila homolog (dMLF) ameliorates the toxicity of poly(Q) expressed in the eye and central nervous system. In the retina, whether endogenously or ectopically expressed, dMLF co-localized with aggregates, suggesting that dMLF alone, or through an intermediary molecular partner, may suppress toxicity by sequestering poly(Q) and/or its aggregates.

Directed Selection of Biochars for Amending Metal ...

EPA Pesticide Factsheets

Approximately 500,000 abandoned mines across the U.S. pose a considerable, pervasive risk to human health and the environment. World-wide the problem is even larger. Lime, organic matter, biosolids and other amendments have been used to decrease metal bioavailability in contaminated mine wastes and to promote the development of a mine waste stabilizing plant cover. The demonstrated properties of biochar make it a viable candidate as an amendment for remediating metal contaminated mine soils. In addition to sequestering potentially toxic metals, biochar can also be a source of plant nutrients, used to adjust soil pH, improve soil water holding characteristics, and increase soil carbon content. However, methods are needed for matching biochar beneficial properties with mine waste toxicities and soil health deficiencies. In this presentation we will report on a study in which we used mine soil from an abandoned Cu and Zn mine to develop a three-step procedure for identifying biochars that are most effective at reducing heavy metal bioavailability. Step 1: a slightly acidic extract of the mine spoil soil was produced, representing the potentially available metals, and used to identify metal removal properties of a library of 38 different biochars (e.g., made from a variety of feedstocks and pyrolysis or gasification conditions). Step 2: evaluation of how well these biochars retained (i.e., did not desorb) previously sorbed metals. Step 3: laboratory evalua

Sodium ion channel alkaloid resistance does not vary with toxicity in aposematic Dendrobates poison frogs: An examination of correlated trait evolution

PubMed Central

Wang, Ian J.

2018-01-01

Spatial heterogeneity in the strength or agents of selection can lead to geographic variation in ecologically important phenotypes. Many dendrobatid frogs sequester alkaloid toxins from their diets and often exhibit fixed mutations at NaV1.4, a voltage-gated sodium ion channel associated with alkaloid toxin resistance. Yet previous studies have noted an absence of resistance mutations in individuals from several species known to sequester alkaloid toxins, suggesting possible intraspecific variation for alkaloid resistance in these species. Toxicity and alkaloid profiles vary substantially between populations in several poison frog species (genus Dendrobates) and are correlated with variation in a suite of related traits such as aposematic coloration. If resistance mutations are costly, due to alterations of channel gating properties, we expect that low toxicity populations will have reduced frequencies and potentially even the loss of resistance alleles. Here, we examine whether intraspecific variation in toxicity in three dendrobatid frogs is associated with intraspecific variation in alleles conferring toxin resistance. Specifically, we examine two species that display marked variation in toxicity throughout their native ranges (Dendrobates pumilio and D. granuliferus) and one species with reduced toxicity in its introduced range (D. auratus). However, we find no evidence for population-level variation in alkaloid resistance at NaV1.4. In fact, contrary to previous studies, we found that alkaloid resistance alleles were not absent in any populations of these species. All three species exhibit fixed alkaloid resistance mutations throughout their ranges, suggesting that these mutations are maintained even when alkaloid sequestration is substantially reduced. PMID:29534110

Assessing potential dietary toxicity of heavy metals in selected vegetables and food crops*

PubMed Central

Islam, Ejaz ul; Yang, Xiao-e; He, Zhen-li; Mahmood, Qaisar

2007-01-01

Heavy metals, such as cadmium, copper, lead, chromium and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. Their presence in the atmosphere, soil and water, even in traces can cause serious problems to all organisms, and heavy metal bioaccumulation in the food chain especially can be highly dangerous to human health. Heavy metals enter the human body mainly through two routes namely: inhalation and ingestion, ingestion being the main route of exposure to these elements in human population. Heavy metals intake by human populations through food chain has been reported in many countries. Soil threshold for heavy metal toxicity is an important factor affecting soil environmental capacity of heavy metal and determines heavy metal cumulative loading limits. For soil-plant system, heavy metal toxicity threshold is the highest permissible content in the soil (total or bioavailable concentration) that does not pose any phytotoxic effects or heavy metals in the edible parts of the crops does not exceed food hygiene standards. Factors affecting the thresholds of dietary toxicity of heavy metal in soil-crop system include: soil type which includes soil pH, organic matter content, clay mineral and other soil chemical and biochemical properties; and crop species or cultivars regulated by genetic basis for heavy metal transport and accumulation in plants. In addition, the interactions of soil-plant root-microbes play important roles in regulating heavy metal movement from soil to the edible parts of crops. Agronomic practices such as fertilizer and water managements as well as crop rotation system can affect bioavailability and crop accumulation of heavy metals, thus influencing the thresholds for assessing dietary toxicity of heavy metals in the food chain. This paper reviews the phytotoxic effects and bioaccumulation of heavy metals in vegetables and food crops and assesses soil heavy metal thresholds for potential dietary toxicity. PMID:17173356

Assessing potential dietary toxicity of heavy metals in selected vegetables and food crops.

PubMed

Islam, Ejaz ul; Yang, Xiao-e; He, Zhen-li; Mahmood, Qaisar

2007-01-01

Heavy metals, such as cadmium, copper, lead, chromium and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. Their presence in the atmosphere, soil and water, even in traces can cause serious problems to all organisms, and heavy metal bioaccumulation in the food chain especially can be highly dangerous to human health. Heavy metals enter the human body mainly through two routes namely: inhalation and ingestion, ingestion being the main route of exposure to these elements in human population. Heavy metals intake by human populations through food chain has been reported in many countries. Soil threshold for heavy metal toxicity is an important factor affecting soil environmental capacity of heavy metal and determines heavy metal cumulative loading limits. For soil-plant system, heavy metal toxicity threshold is the highest permissible content in the soil (total or bioavailable concentration) that does not pose any phytotoxic effects or heavy metals in the edible parts of the crops does not exceed food hygiene standards. Factors affecting the thresholds of dietary toxicity of heavy metal in soil-crop system include: soil type which includes soil pH, organic matter content, clay mineral and other soil chemical and biochemical properties; and crop species or cultivars regulated by genetic basis for heavy metal transport and accumulation in plants. In addition, the interactions of soil-plant root-microbes play important roles in regulating heavy metal movement from soil to the edible parts of crops. Agronomic practices such as fertilizer and water managements as well as crop rotation system can affect bioavailability and crop accumulation of heavy metals, thus influencing the thresholds for assessing dietary toxicity of heavy metals in the food chain. This paper reviews the phytotoxic effects and bioaccumulation of heavy metals in vegetables and food crops and assesses soil heavy metal thresholds for potential dietary toxicity.

Novel endotoxin-sequestering compounds with terephthalaldehyde-bis-guanylhydrazone scaffolds.

PubMed

Khownium, Kriangsak; Wood, Stewart J; Miller, Kelly A; Balakrishna, Rajalakshmi; Nguyen, Thuan B; Kimbrell, Matthew R; Georg, Gunda I; David, Sunil A

2006-03-01

We have shown that lipopolyamines bind to the lipid A moiety of lipopolysaccharide, a constituent of Gram-negative bacterial membranes, and neutralize its toxicity in animal models of endotoxic shock. In an effort to identify non-polyamine scaffolds with similar endotoxin-recognizing features, we had observed an unusually high frequency of hits containing guanylhydrazone scaffolds in high-throughput screens. We now describe the syntheses and preliminary structure-activity relationships in a homologous series of bis-guanylhydrazone compounds decorated with hydrophobic functionalities. These first-generation compounds bind and neutralize lipopolysaccharide with a potency comparable to that of polymyxin B, a peptide antibiotic known to sequester LPS.

Nuclear micro-probe analysis of Arabidopsis thaliana leaves

NASA Astrophysics Data System (ADS)

Ager, F. J.; Ynsa, M. D.; Domínguez-Solís, J. R.; López-Martín, M. C.; Gotor, C.; Romero, L. C.

2003-09-01

Phytoremediation is a cost-effective plant-based approach for remediation of soils and waters which takes advantage of the remarkable ability of some plants to concentrate elements and compounds from the environment and to metabolize various molecules in their tissues, such as toxic heavy metals and organic pollutants. Nowadays, phytoremediation technology is becoming of paramount importance when environmental decontamination is concerned, due to the emerging knowledge of its physiological and molecular mechanisms and the new biological and engineering strategies designed to optimize and improve it. In addition, the feasibility of using plants for environmental cleanup has been confirmed by many different trials around the world. Arabidopsis thaliana plants can be used for basic studies to improve the technology on phytoremediation. Making use of nuclear microscopy techniques, in this paper we study leaves of wild type and transgenic A. thaliana plants grown in a cadmium-rich environment under different conditions. Micro-PIXE, RBS and SEM analyses, performed on the scanning proton micro-probe at the CNA in Seville (Spain), prove that cadmium is preferentially sequestered in the central region of epidermal trichome and allow comparing the effects of genetic modifications.

Toxicities and risk assessment of heavy metals in sediments of Taihu Lake, China, based on sediment quality guidelines.

PubMed

Zhang, Yanfeng; Han, Yuwei; Yang, Jinxi; Zhu, Lingyan; Zhong, Wenjue

2017-12-01

The occurrence, toxicities, and ecological risks of five heavy metals (Pb, Cu, Cd, Zn and Ni) in the sediment of Taihu Lake were investigated in this study. To evaluate the toxicities caused by the heavy metals, the toxicities induced by organic contaminants and ammonia in the sediments were screened out with activated carbon and zeolite. The toxicities of heavy metals in sediments were tested with benthic invertebrates (tubificid and chironomid). The correlations between toxicity of sediment and the sediment quality guidelines (SQGs) derived previously were evaluated. There were significant correlations (p<0.0001) between the observed toxicities and the total risk quotients of the heavy metals based on SQGs, indicating that threshold effect level (TEL) and probable effect level (PEL) were reliable to predict the toxicities of heavy metals in the sediments of Taihu Lake. By contrast, the method based on acid volatile sulfides (AVS) and simultaneously extracted metals (SEM), such as ∑SEM/AVS and ∑SEM-AVS, did not show correlations with the toxicities. Moreover, the predictive ability of SQGs was confirmed by a total predicting accuracy of 77%. Ecological risk assessment based on TELs and PELs showed that the contaminations of Pb, Cu, Cd and Zn in the sediments of Taihu Lake were at relatively low or medium levels. The risks caused by heavy metals in the sediments of northern bay of the lake, which received more wastewater discharge from upper stream, were higher than other area of the lake. Copyright © 2017. Published by Elsevier B.V.

Metal-organic framework templated synthesis of porous inorganic materials as novel sorbents

DOEpatents

Taylor-Pashow, Kathryn M. L.; Lin, Wenbin; Abney, Carter W.

2017-03-21

A novel metal-organic framework (MOF) templated process for the synthesis of highly porous inorganic sorbents for removing radionuclides, actinides, and heavy metals is disclosed. The highly porous nature of the MOFs leads to highly porous inorganic sorbents (such as oxides, phosphates, sulfides, etc) with accessible surface binding sites that are suitable for removing radionuclides from high level nuclear wastes, extracting uranium from acid mine drainage and seawater, and sequestering heavy metals from waste streams. In some cases, MOFs can be directly used for removing these metal ions as MOFs are converted to highly porous inorganic sorbents in situ.

Removal of metal ions from aqueous solution

DOEpatents

Jackson, Paul J.; Delhaize, Emmanuel; Robinson, Nigel J.; Unkefer, Clifford J.; Furlong, Clement

1990-01-01

A method of removing heavy metals from aqueous solution, a composition of matter used in effecting said removal, and apparatus used in effecting said removal. One or more of the polypeptides, poly (.gamma.-glutamylcysteinyl)glycines, is immobilized on an inert material in particulate form. Upon contact with an aqueous solution containing heavy metals, the polypeptides sequester the metals, removing them from the solution. There is selectivity of poly (.gamma.-glutamylcysteinyl)glycines having a particular number of monomer repeat units for particular metals. The polypeptides are easily regenerated by contact with a small amount of an organic acid, so that they can be used again to remove heavy metals from solution. This also results in the removal of the metals from the column in a concentrated form.

Compositions containing poly (.gamma.-glutamylcysteinyl)glycines

DOEpatents

Jackson, Paul J.; Delhaize, Emmanuel; Robinson, Nigel J.; Unkefer, Clifford J.; Furlong, Clement

1992-01-01

A method of removing heavy metals from aqueous solution, a composition of matter used in effecting said removal, and apparatus used in effecting said removal. One or more of the polypeptides, poly (.gamma.-glutamylcysteinyl)glycines, is immobilized on an inert material in particulate form. Upon contact with an aqueous solution containing heavy metals, the polypeptides sequester the metals, removing them from the solution. There is selectivity of poly (.gamma.-glutamylcysteinyl)glycines having a particular number of monomer repeat units for particular metals. The polypeptides are easily regenerated by contact with a small amount of an organic acid, so that they can be used again to remove heavy metals from solution. This also results in the removal of the metals from the column in a concentrated form.

Biomedical Implications of Heavy Metals Induced Imbalances in Redox Systems

PubMed Central

Singh, Shweta; Siddiqi, Nikhat J.

2014-01-01

Several workers have extensively worked out the metal induced toxicity and have reported the toxic and carcinogenic effects of metals in human and animals. It is well known that these metals play a crucial role in facilitating normal biological functions of cells as well. One of the major mechanisms associated with heavy metal toxicity has been attributed to generation of reactive oxygen and nitrogen species, which develops imbalance between the prooxidant elements and the antioxidants (reducing elements) in the body. In this process, a shift to the former is termed as oxidative stress. The oxidative stress mediated toxicity of heavy metals involves damage primarily to liver (hepatotoxicity), central nervous system (neurotoxicity), DNA (genotoxicity), and kidney (nephrotoxicity) in animals and humans. Heavy metals are reported to impact signaling cascade and associated factors leading to apoptosis. The present review illustrates an account of the current knowledge about the effects of heavy metals (mainly arsenic, lead, mercury, and cadmium) induced oxidative stress as well as the possible remedies of metal(s) toxicity through natural/synthetic antioxidants, which may render their effects by reducing the concentration of toxic metal(s). This paper primarily concerns the clinicopathological and biomedical implications of heavy metals induced oxidative stress and their toxicity management in mammals. PMID:25184144

Study on the Effect of Heavy metals toxicity according to changing Hardness concentration using D.magna

NASA Astrophysics Data System (ADS)

Chun Sang, H.

2016-12-01

n order to determine and prevent the number of ecological effects of heavy metals in the materials, we have to accurately measure the heavy metals present in the water-based protection ecosystems and may determine the effects to humans. Heavy metals occurred in the industrial effluent which is a state in which the monitor, based on the emission standards are made by the Ministry of Environment and managed and waste water contained Copper, Zinc, lead, etc. These heavy metals are able to express the toxic effects only when present in the free-ions in the aqueous condition, which appears differently affected by the degree to hardness change in accordance with the season, precipitation. Generally changing hardness concentration can not precisely evaluate toxic effects of heavy metals in the water system. Anderson announced a study on bioassay for heavy metals from industrial waste water using Daphnia magna(Anderson, 1944, 1948). Breukelman published study the resitivity difference for the mercury Chloride(HgCl2). Braudouin(1974) compared the zooplankton(Daphnia sp.) acute toxicity of the different heavy metals and confirmed the sensitivity. Shcherban(1979) presented for toxicity evaluation results for the heavy metal of the Daphnia magna according to different temperature conditions. In the United States Environmental Protection Agency(EPA) established a standard test method for water fleas, managed and supervised water ecosystems, and announced the adoption of a bioassay standard method. This study was performed to evaluate acute inhibition using the Daphnia magna for the biological effect of heavy metal ions in water-based toxicity in the hardness change. Evaluation methods were conducted in EPA Water Quality process test criteria. TU(Toxic Unit), NOEC (No Observable Effect Concentration), LOEC (Lowest Observable Effect Concentration), EC50 (Median Effective Concentration) was calculated by Toxcalc 5.0 Program. Keywords : D. magna, Hardness, Toxic Unit, Heavy metal, Industrial effluent Acknowledgement This research was supported by a grant (16IFIP-B089908-03) from Plant Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government. * Corresponding author E-mail address : hcs103@gmail.com(Chun Sang Hong, Ph.D.)

Determination of heavy metal toxicity of finished leather solid waste.

PubMed

Aslan, Ahmet

2009-05-01

This paper investigates the toxicity in leather products of heavy metals known to be detrimental to the ecosystem. Heavy metal concentrations in leather samples were identified with ICP-OES, and toxicity was determined using a MetPLATE bioassay. Chromium and aluminium were found to constitute 98% of the total concentration of heavy metals in finished leather tanned with chromium and aluminium salts, while in some vegetable-tanned leather, zirconium was the only heavy metal identified. The average inhibition values for chromium, aluminium and vegetable tanned leather were 98.08%, 97.04% and 62.36%, respectively.

Effects of chromium, copper, nickel, and zinc on survival and feeding of the cladoceran Moina macrocopa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wong, C.K.

1992-10-01

Heavy metals are widely recognized as highly toxic and dangerous. Past research activities on heavy metal pollution in Hong Kong have emphasized coastal environmentals. Since the main sources of heavy metals are the discharge and spillage of wastewater from electroplating factories, concentrations of heavy metals in streams and pools near industrial areas may be higher than those in coastal waters. Electroplating wastewater in Hong Kong contains high levels of chromium, copper, nickel and zinc. The toxicity of these heavy metals to the aquatic organisms has been extensively reviewed. Toxicity information for invertebrates shows that crustaceans are among the most sensitivemore » organisms. Of the crustacean species tested, cladocerans appear to be the most susceptibile. Cladocerans are important components of many aquatic ecosystems. Despite their importance in many freshwater communities and their sensitivity to heavy metal toxicity, information on the toxicity of heavy metals to cladocerans is limited except for several Daphnia species. In Hong Kong the freshwater cladoceran Moina macrocopa occurs in small ponds and rice paddies and is mass cultured by some farmers as a high quality fish food. The objectives of this study are to determine the effects of various heavy metals on the survival and feeding of M. macrocopa. 12 refs., 2 figs., 1 tab.« less

Hydrogen sulfide alleviates mercury toxicity by sequestering it in roots or regulating reactive oxygen species productions in rice seedlings.

PubMed

Chen, Zhen; Chen, Moshun; Jiang, Ming

2017-02-01

Soil mercury (Hg) contamination is a major factor that affects agricultural yield and food security. Hydrogen sulfide (H 2 S) plays multifunctional roles in mediating a variety of responses to abiotic stresses. The effects of exogenous H 2 S on rice (Oryza sativa var 'Nipponbare') growth and metabolism under mercuric chloride (HgCl 2 ) stress were investigated in this study. Either 100 or 200 μM sodium hydrosulfide (NaHS, a donor of H 2 S) pretreatment improved the transcription of bZIP60, a membrane-associated transcription factor, and then enhanced the expressions of non-protein thiols (NPT) and metallothioneins (OsMT-1) to sequester Hg in roots and thus inhibit Hg transport to shoots. Meanwhile, H 2 S promoted seedlings growth significantly even in the presences of Hg and superoxide dismutase (SOD, EC 1.15.1.1) or catalase (CAT, EC 1.11.1.6) inhibitors, diethyldithiocarbamate (DDC) or 3-amino-1,2,4-triazole (AT). H 2 S might act as an antioxidant to inhibit or scavenge reactive oxygen species (ROS) productions for maintaining the lower MDA and H 2 O 2 levels, and thereby preventing oxidative damages. All these results indicated H 2 S effectively alleviated Hg toxicity by sequestering it in roots or by regulating ROS in seedlings and then thus significantly promoted rice growth. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Compositions containing poly ([gamma]glutamylcysteinyl)glycines

DOEpatents

Jackson, P.J.; Delhaize, E.; Robinson, N.J.; Unkefer, C.J.; Furlong, C.

1992-02-18

A method of removing heavy metals from aqueous solution, a composition of matter used in effecting the removal, and the apparatus used in effecting the removal are described. One or more of the polypeptides, poly ([gamma]glutamylcysteinyl)glycines, is immobilized on an inert material in particulate form. Upon contact with an aqueous solution containing heavy metals, the polypeptides sequester the metals, removing them from the solution. There is selectivity of poly ([gamma]glutamylcysteinyl)glycines having a particular number of monomer repeat units for particular metals. The polypeptides are easily regenerated by contact with a small amount of an organic acid, so that they can be used again to remove heavy metals from solution. This also results in the removal of the metals from the column in a concentrated form. 1 figs.

[Use of dinoflagellates as a metal toxicity assessment tool in aquatic system].

PubMed

Yuan, Li-juan; He, Meng-chang

2009-10-15

Although dinoflagellates have been used to assess biological toxicity of contaminants, this method still lacks of corresponding toxicity assessment standard. This study appraised the toxicity of selected heavy metals to dinoflagellates based on the dinoflagellates bioluminescence with QwikLite developed by the United States Navy. The results show that single heavy metal biological toxicity is in the order: Hg2+ > Cu2+ > Cd2+ > As5+ > Pb2+ > Cr6+; Two, three and four heavy metal mixture experiments show synergism primarily, antagonism is in minority. pH has not remarkable effect on dinoflagellates, they can be applied directly in natural water, but pH influence Hg2+ and Cu2+ toxicity greatly, eliminating the influence of pH is essential when doing these two kind of ions measurements. The nutrients has little influence on dinoflagellates, change in COD has obvious effect on the response relationships between dinoflagellates and Hg2+ or CU2+. Metal toxicity assessment using dinoflagellates shows great sensitivity, narrow response scope and high stability. Dinoflagellates are good species for heavy metal biological toxicity test in aquatic system.

Re-directing bacterial microcompartment systems to enhance recombinant expression of lysis protein E from bacteriophage ΦX174 in Escherichia coli

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yung, Mimi C.; Bourguet, Feliza A.; Carpenter, Timothy S.

Recombinant expression of toxic proteins remains a challenging problem. Furthermore, one potential method to shield toxicity and thus improve expression of these proteins is to encapsulate them within protein compartments to sequester them away from their targets. Many bacteria naturally produce so-called bacterial microcompartments (BMCs) in which enzymes comprising a biosynthetic pathway are encapsulated in a proteinaeous shell, which is in part thought to shield the cells from the toxicity of reaction intermediates. As a proof-of-concept, we attempted to encapsulate toxic, lysis protein E (E) from bacteriophage ΦX174 inside recombinant BMCs to enhance its expression and achieve higher yields duringmore » downstream purification.« less

Re-directing bacterial microcompartment systems to enhance recombinant expression of lysis protein E from bacteriophage ΦX174 in Escherichia coli

DOE PAGES

Yung, Mimi C.; Bourguet, Feliza A.; Carpenter, Timothy S.; ...

2017-04-26

Recombinant expression of toxic proteins remains a challenging problem. Furthermore, one potential method to shield toxicity and thus improve expression of these proteins is to encapsulate them within protein compartments to sequester them away from their targets. Many bacteria naturally produce so-called bacterial microcompartments (BMCs) in which enzymes comprising a biosynthetic pathway are encapsulated in a proteinaeous shell, which is in part thought to shield the cells from the toxicity of reaction intermediates. As a proof-of-concept, we attempted to encapsulate toxic, lysis protein E (E) from bacteriophage ΦX174 inside recombinant BMCs to enhance its expression and achieve higher yields duringmore » downstream purification.« less

Survival of Salmonella, Escherichia coli 0157:H7, non-0157 shiga toxin producing E.coli, and potential surrogate bacteria in crop soil as affected by the addition of fast pyrolysis-generated switchgrass biochar

USDA-ARS?s Scientific Manuscript database

Fast pyrolysis of switchgrass (and resultant biochar) can be used for bio-fuel production, soil amendments for fertilizing crops, binding heavy metals, and sequestering environmental biocarbon. To determine the influence of fast pyrolysis-generated switchgrass biochar on survival of foodborne path...

Bioengineered Chimeric Spider Silk-Uranium Binding Proteins

PubMed Central

Krishnaji, Sreevidhya Tarakkad; Kaplan, David L.

2014-01-01

Heavy metals constitute a source of environmental pollution. Here, novel functional hybrid biomaterials for specific interactions with heavy metals are designed by bioengineering consensus sequence repeats from spider silk of Nephila clavipes with repeats of a uranium peptide recognition motif from a mutated 33-residue of calmodulin protein from Paramecium tetraurelia. The self-assembly features of the silk to control nanoscale organic/inorganic material interfaces provides new biomaterials for uranium recovery. With subsequent enzymatic digestion of the silk to concentrate the sequestered metals, options can be envisaged to use these new chimeric protein systems in environmental engineering, including to remediate environments contaminated by uranium. PMID:23212989

Heavy metal toxicity to bacteria - are the existing growth media accurate enough to determine heavy metal toxicity?

PubMed

Rathnayake, I V N; Megharaj, Mallavarapu; Krishnamurti, G S R; Bolan, Nanthi S; Naidu, Ravi

2013-01-01

A new minimal medium was formulated considering the limitations of the existing media for testing heavy metal sensitivity to bacteria. Toxicity of cadmium and copper to three bacteria was investigated in the new medium and compared with three other media commonly used to study the effect of the toxic metals. Based on speciation data arrived at using ion-selective electrodes, the available free-metal concentration in solution was highest in the MES-buffered medium. This finding was strongly supported by the estimated EC(50) values for the metals tested based on the toxicity bioassays. The free-ionic cadmium and copper concentrations in the medium provide more accurate determination of metal concentrations that affects the bacteria, than with most of other existing media. This will avoid doubts on other media and misleading conclusions relevant to the toxicity of heavy metals to bacteria and provides a better option for the study of metal-bacteria interactions. Copyright © 2012 Elsevier Ltd. All rights reserved.

Assessment of combined toxicity of heavy metals from industrial wastewaters on Photobacterium phosphoreum T3S

NASA Astrophysics Data System (ADS)

Zeb, BibiSaima; Ping, Zheng; Mahmood, Qaisar; Lin, Qiu; Pervez, Arshid; Irshad, Muhammad; Bilal, Muhammad; Bhatti, Zulfiqar Ahmad; Shaheen, Shahida

2017-07-01

This research work is focusing on the toxicities of heavy metals of industrial origin to anaerobic digestion of the industrial wastewater. Photobacterium phosphoreum T3S was used as an indicator organism. The acute toxicities of heavy metals on P. phosphoreum T3S were assessed during 15-min half inhibitory concentration (IC50) as indicator at pH 5.5-6. Toxicity assays involved the assessment of multicomponent mixtures using TU and MTI approaches. The results of individual toxicity indicated that the toxicity of Cd, Cu and Pb on P. phosphoreum increased with increasing concentrations and there was a linear correlation. The 15-min IC50 values of Cd, Cu and Pb were 0.537, 1.905 and 1.231 mg/L, respectively, and their toxic order was Cd > Pb > Cu. The combined effects of Cd, Cu and Pb were assayed by equivalent concentration mixing method. The results showed that the combined effects of Cd + Cu, Cd + Pb, Cu + Pb, Cd + Cu + Pb were antagonistic, antagonistic and partly additive. The combined effect of three heavy metals was partly additive.

Risk analysis of pyrolyzed biochar made from paper mill effluent treatment plant sludge for bioavailability and eco-toxicity of heavy metals.

PubMed

Devi, Parmila; Saroha, Anil K

2014-06-01

The risk analysis was performed to study the bioavailability and eco-toxicity of heavy metals in biochar obtained from pyrolysis of sludge of pulp and paper mill effluent treatment plant. The sludge was pyrolyzed at different temperatures (200-700°C) and the resultant biochar were analyzed for fractionation of heavy metals by sequential extraction procedure. It was observed that all the heavy metals get enriched in biochar matrix after pyrolysis, but the bioavailability and eco-toxicity of the heavy metals in biochar were significantly reduced as the mobile and bioavailable heavy metal fractions were transformed into the relatively stable fractions. Moreover, it was observed that the leaching potential of heavy metals decreased after pyrolysis and the best results were obtained for biochar pyrolyzed at 700°C. Copyright © 2014 Elsevier Ltd. All rights reserved.

High levels of heavy metal accumulation in dental calculus of smokers: a pilot inductively coupled plasma mass spectrometry study.

PubMed

Yaprak, E; Yolcubal, I; Sinanoğlu, A; Doğrul-Demiray, A; Guzeldemir-Akcakanat, E; Marakoğlu, I

2017-02-01

Various trace elements, including toxic heavy metals, may exist in dental calculus. However, the effect of environmental factors on heavy metal composition of dental calculus is unknown. Smoking is a major environmental source for chronic toxic heavy metal exposition. The aim of this study is to compare toxic heavy metal accumulation levels in supragingival dental calculus of smokers and non-smokers. A total of 29 supragingival dental calculus samples were obtained from non-smoker (n = 14) and smoker (n = 15) individuals. Subjects with a probability of occupational exposure were excluded from the study. Samples were analyzed by inductively coupled plasma mass spectrometry in terms of 26 metals and metalloids, including toxic heavy metals. Toxic heavy metals, arsenic (p < 0.05), cadmium (p < 0.05), lead (p < 0.01), manganese (p < 0.01) and vanadium (p < 0.01) levels were significantly higher in smokers than non-smokers. The levels of other examined elements were similar in both groups (p > 0.05). Within the limitations of this study, it can be concluded that the elementary composition of dental calculus may be affected by environmental factors such as tobacco smoke. Therefore, dental calculus may be utilized as a non-invasive diagnostic biological material for monitoring chronic oral heavy metal exposition. However, further studies are required to evaluate its diagnostic potential. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Distribution, relationship, and risk assessment of toxic heavy metals in walnuts and growth soil.

PubMed

Han, Yongxiang; Ni, Zhanglin; Li, Shiliang; Qu, Minghua; Tang, Fubin; Mo, Runhong; Ye, Caifen; Liu, Yihua

2018-04-14

Walnut is one of the most popular nuts worldwide and contains various mineral nutrients. Little is known, however, about the relationship between toxic heavy metals in walnuts and growth soil. In this study, we investigated the distribution, relationship, and risk assessment of five toxic heavy metals-lead (Pb), arsenic (As), chromium (Cr), cadmium (Cd), and mercury (Hg)-in walnuts and growth soil in the main production areas of China. The results showed that the main heavy metal pollution in walnut and soil was Pb and Cd. Regionally, positive relationships existed between heavy metals and the pH and organic matter of soil. In addition, we observed a notable uptake effect between walnut and growth soil. In this study, we found a significant correlation (r = 0.786, P < 0.05) between the bioconcentration factors and the longitude of the sampling areas. The risks (total hazard quotients) of five heavy metals toward children and adults by dietary walnut consumption were 46.8 and 56.2%, respectively. The ability to identify toxic heavy metal pollution in walnuts and growth soil could be helpful to screen suitable planting sites to prevent and control heavy metal pollution and improve the quality and safety of walnut.

An in vitro cytotoxic approach to assess the toxicity of heavy metals and their binary mixtures on hippocampal HT-22 cell line.

PubMed

Karri, Venkatanaidu; Kumar, Vikas; Ramos, David; Oliveira, Eliandre; Schuhmacher, Marta

2018-01-05

Humans are exposed to a cocktail of heavy metal toxicants in the environment. Though heavy metals are deleterious, there is a paucity of information on the toxicity of mixtures. In this study, four common neurotoxicity heavy metals lead (Pb) cadmium (Cd), arsenic (As), and methylmercury (MeHg) were exposed individually and as mixtures to HT-22 cell line for 8days. The study established that low dose exposures induced toxicity to the HT-22 cell line during 8days. The results indicates potency dependent response, the toxicity of single metals on the HT-22 cells; MeHg > As > Cd > Pb. The cytotoxicity data of single metals were used to determine the mixtures interaction profile by using the dose additivity and effect additivity method. Metal mixtures showed higher toxicities compared to individual metals. Synergistic, antagonistic or additive effects of the toxicity were observed in different mixtures in low dose exposure. The interactive responses of mixtures depend on the co-exposure metal and their respective concentration. We concluded that the combined effects should be considered in the risk assessment of heavy metal co-exposure and potency. In future, comprehensive mechanistic based investigations needed for understanding the real interactive mixtures effects at molecular level. Copyright © 2017 Elsevier B.V. All rights reserved.

Assessment of interference in biosorption of a heavy metal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Figueira, M.M.; Volesky, B.; Ciminelli, V.S.T.

1997-05-20

Biosorption of heavy metals by various biological materials has been studied extensively in the last decade due to its potential particularly in wastewater treatment. The presence of a large number of metals in industrial metal-bearing solutions makes it necessary to investigate their effect on the final metal uptake by individual biosorbent materials. Nonliving biomass of Sargassum, a brown marine alga, is capable of binding more than 10% of its dry weight in toxic cadmium ions. Although ubiquitous iron interferes with Cd uptake, only approximately 4.5% of it is sequestered (biomass dry weight). Biosorption of both metals at pH 4.5 couldmore » be described by Langmuir-type isotherms with b, the affinity-related coefficient (Cd: b = 0.015; Fe: b = 0.027). The interference of Fe with Cd uptake, and vice versa, was assessed by deriving three-dimensional equilibrium two-metal sorption isotherm surfaces, smoothed and cut to reveal the inhibition effect of Fe on biosorption of Cd: at the equilibrium concentration Cf[Cd] = 1.5 mM, the presence of Fe at 1.5 mM equilibrium concentration suppressed the Cd uptake to only 76% of the original value. For 50% Cd uptake reduction, a very high equilibrium Fe presence of 4.5 mM was required. The Cd presence affected the uptake of Fe very strongly. To obtain equal values of uptake for each metal in the biosorbent, the ratio of equilibrium concentrations of 0.42 Cd to 1 Fe is necessary in the liquid phase.« less

Toxic responses of bivalves to metal mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mathew, P.; Menon, N.R.

Although there is a growing body of information on the toxicity of individual heavy metals to economically important on the toxicity of individual heavy metals to economically important species of bivalves, literature on the lethal toxicity of metal mixtures to bivalves under controlled conditions is rather limited. In the present investigation the toxic effects of combinations of copper - mercury and copper - mercury and copper - cadmium at lethal levels of two marine bivalve species, Perna indica and Donax incarnatus, have been delineated.

Probiotic Lactobacillus rhamnosus Reduces Organophosphate Pesticide Absorption and Toxicity to Drosophila melanogaster

PubMed Central

Trinder, Mark; McDowell, Tim W.; Daisley, Brendan A.; Ali, Sohrab N.; Leong, Hon S.; Sumarah, Mark W.

2016-01-01

ABSTRACT Organophosphate pesticides used in agriculture can pose health risks to humans and wildlife. We hypothesized that dietary supplementation with Lactobacillus, a genus of commensal bacteria, would reduce absorption and toxicity of consumed organophosphate pesticides (parathion and chlorpyrifos [CP]). Several Lactobacillus species were screened for toleration of 100 ppm of CP or parathion in MRS broth based on 24-h growth curves. Certain Lactobacillus strains were unable to reach stationary-phase culture maxima and displayed an abnormal culture morphology in response to pesticide. Further characterization of commonly used, pesticide-tolerant and pesticide-susceptible, probiotic Lactobacillus rhamnosus strain GG (LGG) and L. rhamnosus strain GR-1 (LGR-1), respectively, revealed that both strains could significantly sequester organophosphate pesticides from solution after 24-h coincubations. This effect was independent of metabolic activity, as L. rhamnosus GG did not hydrolyze CP and no difference in organophosphate sequestration was observed between live and heat-killed strains. Furthermore, LGR-1 and LGG reduced the absorption of 100 μM parathion or CP in a Caco-2 Transwell model of the small intestine epithelium. To determine the effect of sequestration on acute toxicity, newly eclosed Drosophila melanogaster flies were exposed to food containing 10 μM CP with or without supplementation with live LGG. Supplementation with LGG simultaneously, but not with administration of CP 3 days prior (prophylactically), mitigated CP-induced mortality. In summary, the results suggest that L. rhamnosus may be useful for reducing toxic organophosphate pesticide exposure via passive binding. These findings could be transferable to clinical and livestock applications due to affordability and practical ability to supplement products with food-grade bacteria. IMPORTANCE The consequences of environmental pesticide pollution due to widespread usage in agriculture and soil leaching are becoming a major societal concern. Although the long-term effects of low-dose pesticide exposure for humans and wildlife remain largely unknown, logic suggests that these chemicals are not aligned with ecosystem health. This observation is most strongly supported by the agricultural losses associated with honeybee population declines, known as colony collapse disorder, in which pesticide usage is a likely trigger. Lactobacilli are bacteria used as beneficial microorganisms in fermented foods and have shown potentials to sequester and degrade environmental toxins. This study demonstrated that commonly used probiotic strains of lactobacilli could sequester, but not metabolize, organophosphate pesticides (parathion and chlorpyrifos). This Lactobacillus-mediated sequestration was associated with decreased intestinal absorption and insect toxicity in appropriate models. These findings hold promise for supplementing human, livestock, or apiary foods with probiotic microorganisms to reduce organophosphate pesticide exposure. PMID:27520820

Phytoremediation of Ionic and Methyl Mercury P

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meagher, Richard B.

1999-06-01

Our long-term goal is to enable highly productive plant species to extract, resist, detoxify, and/or sequester toxic heavy metal pollutants as an environmentally friendly alternative to physical remediation methods. We have focused this phytoremediation research on soil and water-borne ionic and methylmercury. Mercury pollution is a serious world-wide problem affecting the health of human and wild-life populations. Methylmercury, produced by native bacteria at mercury-contaminated wetland sites, is a particularly serious problem due to its extreme toxicity and efficient biomagnification in the food chain. We engineered several plant species (e.g., Arabidopsis, tobacco, canola, yellow poplar, rice) to express the bacterial genes,more » merB and/or merA, under the control of plant regulatory sequences. These transgenic plants acquired remarkable properties for mercury remediation. (1) Transgenic plants expressing merB (organomercury lyase) extract methylmercury from their growth substrate and degrade it to less toxic ionic mercury. They grow on concentrations of methylmercury that kill normal plants and accumulate low levels of ionic mercury. (2) Transgenic plants expressing merA (mercuric ion reductase) extract and electrochemically reduce toxic, reactive ionic mercury to much less toxic and volatile metallic mercury. This metal transformation is driven by the powerful photosynthetic reducing capacity of higher plants that generates excess NADPH using solar energy. MerA plants grow vigorously on levels of ionic mercury that kill control plants. Plants expressing both merB and merA degrade high levels of methylmercury and volatilize metallic mercury. These properties were shown to be genetically stable for several generations in the two plant species examined. Our work demonstrates that native trees, shrubs, and grasses can be engineered to remediate the most abundant toxic mercury pollutants. Building on these data our working hypothesis for the next grant period is that transgenic plants expressing the bacterial merB and merA genes will (a) remove mercury from polluted soil and water and (b) prevent methylmercury from entering the food chain. Our specific aims center on understanding the mechanisms by which plants process the various forms of mercury and volatilize or transpire mercury vapor. This information will allow us to improve the design of our current phytoremediation strategies. As an alternative to volatilizing mercury, we are using several new genes to construct plants that will hyperaccumulate mercury in above-ground tissues for later harvest. The Department of Energy's Oak Ridge National Laboratory and Brookhaven National Laboratory have sites with significant levels of mercury contamination that could be cleaned by applying the scientific discoveries and new phytoremediation technologies described in this proposal. The knowledge and expertise gained by engineering plants to hyperaccumulate mercury can be applied to the remediation of other heavy metals pollutants (e.g., arsenic, cesium, cadmium, chromium, lead, strontium, technetium, uranium) found at several DOE facilities.« less

A review of toxicity and mechanisms of individual and mixtures of heavy metals in the environment.

PubMed

Wu, Xiangyang; Cobbina, Samuel J; Mao, Guanghua; Xu, Hai; Zhang, Zhen; Yang, Liuqing

2016-05-01

The rational for the study was to review the literature on the toxicity and corresponding mechanisms associated with lead (Pb), mercury (Hg), cadmium (Cd), and arsenic (As), individually and as mixtures, in the environment. Heavy metals are ubiquitous and generally persist in the environment, enabling them to biomagnify in the food chain. Living systems most often interact with a cocktail of heavy metals in the environment. Heavy metal exposure to biological systems may lead to oxidation stress which may induce DNA damage, protein modification, lipid peroxidation, and others. In this review, the major mechanism associated with toxicities of individual metals was the generation of reactive oxygen species (ROS). Additionally, toxicities were expressed through depletion of glutathione and bonding to sulfhydryl groups of proteins. Interestingly, a metal like Pb becomes toxic to organisms through the depletion of antioxidants while Cd indirectly generates ROS by its ability to replace iron and copper. ROS generated through exposure to arsenic were associated with many modes of action, and heavy metal mixtures were found to have varied effects on organisms. Many models based on concentration addition (CA) and independent action (IA) have been introduced to help predict toxicities and mechanisms associated with metal mixtures. An integrated model which combines CA and IA was further proposed for evaluating toxicities of non-interactive mixtures. In cases where there are molecular interactions, the toxicogenomic approach was used to predict toxicities. The high-throughput toxicogenomics combines studies in genetics, genome-scale expression, cell and tissue expression, metabolite profiling, and bioinformatics.

Ecotoxic heavy metals transformation by bacteria and fungi in aquatic ecosystem.

PubMed

Chaturvedi, Amiy Dutt; Pal, Dharm; Penta, Santhosh; Kumar, Awanish

2015-10-01

Water is the most important and vital molecule of our planet and covers 75% of earth surface. But it is getting polluted due to high industrial growth. The heavy metals produced by industrial activities are recurrently added to it and considered as dangerous pollutants. Increasing concentration of toxic heavy metals (Pb(2+), Cd(2+), Hg(2+), Ni(2+)) in water is a severe threat for human. Heavy metal contaminated water is highly carcinogenic and poisonous at even relatively low concentrations. When they discharged in water bodies, they dissolve in the water and are distributed in the food chain. Bacteria and fungi are efficient microbes that frequently transform heavy metals and remove toxicity. The application of bacteria and fungi may offer cost benefit in water treatment plants for heavy metal transformation and directly related to public health and environmental safety issues. The heavy metals transformation rate in water is also dependent on the enzymatic capability of microorganisms. By transforming toxic heavy metals microbes sustain aquatic and terrestrial life. Therefore the application of microbiological biomass for heavy metal transformation and removal from aquatic ecosystem is highly significant and striking. This paper reviews the microbial transformation of heavy metal, microbe metal interaction and different approaches for microbial heavy metal remediation from water bodies.

Quantitative proteomics of heavy metal exposure in Arabidopsis thaliana reveals alterations in one-carbon metabolism enzymes upon exposure to zinc.

PubMed

Barkla, Bronwyn J; Vera-Estrella, Rosario; Miranda-Vergara, María Cristina; Pantoja, Omar

2014-12-05

Plant zinc (Zn) homeostasis must be tightly regulated as the requirement for this micronutrient necessitates its uptake. However, excessive Zn can lead to toxicity and the plant must respond rapidly and effectively within its capacity to minimize damage. To detect mechanisms that may be important for coping with excess Zn we carried out a quantitative proteomics approach using 2D-DIGE to identify Zn-responsive proteins in microsomal fractions from leaves of 4day, 200μM Zn-treated, Arabidopsis thaliana plants. Of the eight proteins which showed significant changes in abundance in the Zn-treated samples and which met all of the selection criteria following statistical analysis, six were successfully identified by LC-MS/MS with 2 or more unique peptides. Three of the proteins were found to be involved in the one-carbon metabolism pathway; including glycine decarboxylase P protein, serine hydroxymethyltransferase (SHMT) and methionine synthase, all of which showed reduced abundance in the Zn-treated samples. Western blot analysis confirmed the decrease in SHMT, while changes in metal tolerance protein indicated plants were most likely actively sequestering Zn. Interestingly, excess Zn led to increased petiole length, a phenotype which may reflect the reduced levels of methionine, a key product of the one-carbon metabolism pathway. Metal contamination is becoming an increasingly common environmental problem. High levels of zinc can be found in certain soils naturally or as a result of long-term anthropogenic activity which leads to its accumulation; i.e. use of fertilizers or industrial waste. The study of metal tolerant plants, particularly those classified as hyperaccumulators has been driven by the potential use of these plants for bioremediation purposes. However, the effects of heavy metal exposure on sensitive plants and the different cellular processes that are affected have received significantly less attention. We are interested in identifying proteins in A. thaliana that are induced as a result of exposure to subtoxic levels of heavy metals with the aim of discovering novel participants in heavy metal stress and adaptation. Copyright © 2014 Elsevier B.V. All rights reserved.

Acute toxicity and synergism of cadmium and zinc in white shrimp, Penaeus setiferus, Juveniles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vanegas, C.; Espina, S.; Botello, A.V.

1997-01-01

Toxic effects of individual heavy metals on decapod crustaceans have been reported frequently, but little information exists concerning interactions. Among the non-essential heavy metals, cadmium is one of the most hazardous elements in the aquatic environment; on the other hand, zinc is an essential element, but toxic when present in greater than trace amounts. Biological effects of cadmium in aquatic organisms are complex due to the interactions with both environmental variables and other toxic agents. In decapod crustaceans, the toxicity of cadmium and zinc is modified by salinity, temperature, hypoxia, calcium ion concentrations and life-cycle stage. Heavy metal pollution hasmore » increased in the coastal waters of the Gulf of Mexico, particularly in shrimp habitat. This study examined the toxicity of cadmium and zinc to white shrimp juveniles and looked at the interaction of the metals. 16 refs., 2 tabs.« less

Peroxotitanates for Biodelivery of Metals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hobbs, David; Elvington, M.

2009-02-11

Metal-based drugs are largely undeveloped in pharmacology. One limiting factor is the systemic toxicity of metal-based compounds. A solid-phase, sequestratable delivery agent for local delivery of metals could reduce systemic toxicity, facilitating new drug development in this nascent area. Amorphous peroxotitanates (APT) are ion exchange materials with high affinity for several heavy metal ions, and have been proposed to deliver or sequester metal ions in biological contexts. In the current study, we tested a hypothesis that APT are able to deliver metals or metal compounds to cells. We exposed fibroblasts (L929) or monocytes (THP1) to metal-APT materials for 72 hmore » in vitro, then measured cellular mitochondrial activity (SDH-MTT method) to assess the biological impact of the metal-APT materials vs. metals or APT alone. APT alone did not significantly affect cellular mitochondrial activity, but all metal-APT materials suppressed the mitochondrial activity of fibroblasts (by 30-65% of controls). The concentration of metal-APT materials required to suppress cellular mitochondrial activity was below that required for metals alone, suggesting that simple extracellular release of the metals from the metal-APT materials was not the primary mechanism of mitochondrial suppression. In contrast to fibroblasts, no metal-APT material had a measurable effect on THP1 monocyte mitochondrial activity, despite potent suppression by metals alone. This latter result suggested that 'biodelivery' by metal-APT materials may be cell type-specific. Therefore, it appears that APT are plausible solid phase delivery agents of metals or metal compounds to some types of cells for potential therapeutic effect.« less

Geochemical modulation of bioavailability and toxicity of nitroaromatic compounds to aquatic plants.

PubMed

Roberts, Michael G; Rugh, Clayton L; Li, Hui; Teppen, Brian J; Boyd, Stephen A

2007-03-01

Nitroaromatic compounds (NACs) are prominent soil and sediment contaminants that are strongly adsorbed by smectites at extents that depend on hydration properties of the exchangeable cation. Potassium smectites adsorb nitroaromatics much more strongly than calcium smectites, so that adjustment of K+ versus Ca2+ occupation on cation exchange sites in smectites can be used to modulate the retention and release of nitroaromatics. We suggest that this modulation can be used to advantageously manage the bioavailability and toxicity of NACs during bioremedation. We have measured the toxicity of 2,4-dinitrotoluene (2,4-DNT) to duckweed grown in smectite suspensions and utilized Ca2+/K+ exchange to retain or release 2,4-DNT. Retention by potassium smectite reduced bioavailability and hence toxicity to duckweed. Addition of Ca2+ to replace K+ by ion exchange released adsorbed 2,4-DNT, which is toxic to duckweed. So smectites can be used to sequester or release 2,4-DNT predictably and provide means to control bioavailability and environmental toxicity.

Quantitative analysis and reduction of the eco-toxicity risk of heavy metals for the fine fraction of automobile shredder residue (ASR) using H2O2.

PubMed

Singh, Jiwan; Yang, Jae-Kyu; Chang, Yoon-Young

2016-02-01

Automobile shredder residue (ASR) fraction (size <0.25mm) can be considered as hazardous due to presence of high concentrations of heavy metals. Hydrogen peroxide combined with nitric acid has been used for the recovery of heavy metals (Zn, Cu, Mn, Fe, Ni, Pb, Cd and Cr) from the fine fraction of ASR. A sequential extraction procedure has also been used to determine the heavy metal speciation in the fine fraction of ASR before and after treatment. A risk analysis of the fine fraction of ASR before and after treatment was conducted to assess the bioavailability and eco-toxicity of heavy metals. These results showed that the recovery of heavy metals from ASR increased with an increase in the hydrogen peroxide concentration. A high concentration of heavy metals was found to be present in Cbio fractions (the sum of the exchangeable and carbonate fractions) in the fine fraction of ASR, indicating high toxicity risk. The Cbio rate of all selected heavy metals was found to range from 8.6% to 33.4% of the total metal content in the fine fraction of ASR. After treatment, Cbio was reduced to 0.3-3.3% of total metal upon a treatment with 2.0% hydrogen peroxide. On the basis of the risk assessment code (RAC), the environmental risk values for heavy metals in the fine fraction of ASR reflect high risk/medium risk. However, after treatment, the heavy metals would be categorized as low risk/no risk. The present study concludes that hydrogen peroxide combined with nitric acid is a promising treatment for the recovery and reduction of the eco-toxicity risk of heavy metals in ASR. Copyright © 2015 Elsevier Ltd. All rights reserved.

Electrostatic lipid-protein interactions sequester the curli amyloid fold on the lipopolysaccharide membrane surface.

PubMed

Swasthi, Hema M; Mukhopadhyay, Samrat

2017-12-01

Curli is a functional amyloid protein in the extracellular matrix of enteric Gram-negative bacteria. Curli is assembled at the cell surface and consists of CsgA, the major subunit of curli, and a membrane-associated nucleator protein, CsgB. Oligomeric intermediates that accumulate during the lag phase of amyloidogenesis are generally toxic, but the underlying mechanism by which bacterial cells overcome this toxicity during curli assembly at the surface remains elusive. Here, we elucidated the mechanism of curli amyloidogenesis and provide molecular insights into the strategy by which bacteria can potentially bypass the detrimental consequences of toxic amyloid intermediates. Using a diverse range of biochemical and biophysical tools involving circular dichroism, fluorescence, Raman spectroscopy, and atomic force microscopy imaging, we characterized the molecular basis of the interaction of CsgB with a membrane-mimetic anionic surfactant as well as with lipopolysaccharide (LPS) constituting the outer leaflet of Gram-negative bacteria. Aggregation studies revealed that the electrostatic interaction of the positively charged C-terminal region of the protein with a negatively charged head group of surfactant/LPS promotes a protein-protein interaction that results in facile amyloid formation without a detectable lag phase. We also show that CsgB, in the presence of surfactant/LPS, accelerates the fibrillation rate of CsgA by circumventing the lag phase during nucleation. Our findings suggest that the electrostatic interactions between lipid and protein molecules play a pivotal role in efficiently sequestering the amyloid fold of curli on the membrane surface without significant accumulation of toxic oligomeric intermediates. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Removal of toxic heavy metal ions in runoffs by modified alfalfa and juniper

Treesearch

J.S. Han; J.K. Park; S.H. Min

2000-01-01

A series of batch isotherm tests was performed with alfalfa and juniper fibers to evaluate the effectiveness in filtering toxic heavy metals from stormwater. The adsorption of the heavy metal ions on the alfalfa and juniper fibers was strongly dependent on the equilibrium pH value of the solution. The change in sorption rate over time showed that two different sorption...

Removal of metal ions from aqueous solution

DOEpatents

Jackson, Paul J.; Delhaize, Emmanuel; Robinson, Nigel J.; Unkefer, Clifford J.; Furlong, Clement

1990-11-13

A method of removing heavy metals from aqueous solution, a composition of matter used in effecting said removal, and apparatus used in effecting said removal. One or more of the polypeptides, poly (.gamma.-glutamylcysteinyl)glycines, is immobilized on an inert material in particulate form. Upon contact with an aqueous solution containing heavy metals, the polypeptides sequester the metals, removing them from the solution. There is selectivity of poly (.gamma.-glutamylcysteinyl)glycines having a particular number of monomer repeat unit for particular metals. The polypeptides are easily regenerated by contact with a small amount of an organic acid, so that they can be used again to remove heayv metals from solution. This also results in the removal of the metals from the column in a concentrated form.

Distribution, diffusive fluxes, and toxicity of heavy metals and PAHs in pore water profiles from the northern bays of Taihu Lake.

PubMed

Lei, Pei; Zhang, Hong; Shan, Baoqing; Zhang, Bozheng

2016-11-01

Pore water plays a more significant role than do sediments in pollutant cycling dynamics. Also, concentrations of pollutants in pore water provide important information about their bioavailability or eco-toxicity; however, very few studies have focused on this topic. In this study, four duplicate sediment cores from three typical northern bays as well as the central part of Taihu Lake were collected to investigate the distribution, diffusive fluxes, and toxicity of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in pore water profiles, which will be good in understanding the mobility and toxicity of these toxic pollutants and achieving better environmental management. The diffusive fluxes of heavy metals across the sediment-water interface was estimated through Fick's First Law, and the toxicity of heavy metals and PAHs in pore water was assessed by applying a water quality index (interstitial water toxicity criteria unit, IWCTU) and a hazard index (HI), respectively. The average concentrations of Cr, Cu, Ni, Pb, and Zn in surface pore water were 18.8, 23.4, 12.0, 13.5, and 42.5 μg L -1 , respectively. Also, concentrations of the selected heavy metals in both overlying water and pore water from Taihu Lake were all lower than the standard values of the environmental quality standards for surface water. The concentrations as the pore water depth increased, and the highest detected concentrations of heavy metals were recorded between 3 and 5 cm below the sediment surface. The average diffusive fluxes of these metals were 27.3, 24.8, 7.03, 7.81, and -3.32 μg (m 2 day) -1 , respectively, indicating export from sediment into overlying water, with the exception of Zn. There was a potential risk of toxicity, mainly from Pb and Cu, indicating that heavy metals in pore water had slight to moderate impact on sediment-dwelling organisms by values of the IWCTU and the Nemeraw index. The total PAH concentrations in pore water were higher than those in overlying water, and such gradient implies a potential flux of PAHs from pore water to overlying water. The average HI value of PAHs in surface pore water showed no or low ecological risk. While there may be occasional risk due to the HI values in some sites being greater than 1, the dominant contributors were carcinogenic PAHs. Because of their potential biological impact, heavy metals and PAHs and their comprehensive toxic effects in pore water should be given priority attention to keep the safety of Taihu Lake.

Risk and toxicity assessments of heavy metals in sediments and fishes from the Yangtze River and Taihu Lake, China.

PubMed

Fu, Jie; Hu, Xin; Tao, Xiancong; Yu, Hongxia; Zhang, Xiaowei

2013-11-01

Heavy metal pollution is one of the most serous environmental issues globally. To evaluate the metal pollution in Jiangsu Province of China, the total concentrations of heavy metals in sediments and fishes from the Yangtze River and Taihu Lake were analyzed. Ecological risk of sediments and human health risk of fish consumption were assessed respectively. Furthermore, toxicity of samples on expression of the stress responsive genes was evaluated using microbial live cell-array method. The results showed that the heavy metals concentrations in sediments from the Yangtze River were much higher than those in sediments from the Taihu Lake. However, the fishes from the Taihu Lake had higher concentrations of heavy metals than fishes from the Yangtze River. Ecological risk evaluation showed that the heavy metal contaminants in sediments from the Yangtze River posed higher risk of adverse ecological effects, while sediments from the study areas of Taihu Lake were relatively safe. Health risk assessment suggested that the heavy metals in fishes of both Yangtze River and Taihu Lake might have risk of adverse health effects to human. The toxicity assessment indicated that the heavy metals in these sediments and fishes showed transcriptional effects on the selected 21 stress responsive genes, which were involved in the pathways of DNA damage response, chemical stress, and perturbations of electron transport. Together, this field investigation combined with chemical analysis, risk assessment and toxicity bioassay would provide useful information on the heavy metal pollution in Jiangsu Province. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects-driven chemical fractionation of heavy fuel oil to isolate compounds toxic to trout embryos.

PubMed

Bornstein, Jason M; Adams, Julie; Hollebone, Bruce; King, Thomas; Hodson, Peter V; Brown, R Stephen

2014-04-01

Heavy fuel oil (HFO) spills account for approximately 60% of ship-source oil spills and are up to 50 times more toxic than medium and light crude oils. Heavy fuel oils contain elevated concentrations of polycyclic aromatic hydrocarbons (PAHs) and alkyl-PAHs, known to be toxic to fish; however, little direct characterization of HFO toxicity has been reported. An effects-driven chemical fractionation was conducted on HFO 7102 to separate compounds with similar chemical and physical properties, including toxicity, to isolate the groups of compounds most toxic to trout embryos. After each separation, toxicity tests directed the next phase of fractionation, and gas chromatography-mass spectrometry analysis correlated composition with toxicity, with a focus on PAHs. Low-temperature vacuum distillation permitted the separation of HFO into 3 fractions based on boiling point ranges. The most toxic of these fractions underwent wax precipitation to remove long-chain n-alkanes. The remaining PAH-rich extract was further separated using open column chromatography, which provided distinct fractions that were grouped according to increasing aromatic ring count. The most toxic of these fractions was richest in PAHs and alkyl-PAHs. The results of the present study were consistent with previous crude oil studies that identified PAH-rich fractions as the most toxic. © 2013 SETAC.

Mixture cytotoxicity assessment of ionic liquids and heavy metals in MCF-7 cells using mixtox.

PubMed

Zhu, Xiang-Wei; Ge, Hui-Lin; Cao, Yu-Bin

2016-11-01

Ionic liquids (ILs) are widely used as extractants for heavy metals. However, the effect of mixtures of ILs and heavy metals is rarely understood. In this study, we tested the cytotoxicity of four ILs, four heavy metals and their mixtures on human MCF-7 cells in 96-well microplates. The toxicity of single compounds in MCF-7 cells ranges from 3.07 × 10(-6) M for Cu(II) to 2.20 × 10(-3) M for 1-ethyl-3-methylimidazolium tetrafluoroborate. The toxicity of heavy metals in MCF-7 is generally higher than the toxicity of ILs. A uniform experimental design was used to simulate environmentally realistic mixtures. Two classical reference models (concentration addition and independent action) were used to predict their mixture. The experiments to evaluate the toxicity of the mixture revealed antagonism among four ILs and four heavy metals in MCF-7 cells. Pearson correlation analysis showed that Ni(II) and 1-dodecyl-3-methylimidazolium chloride are positively correlated with the extent of antagonism, while 1-hexyl-3-methylimidazolium tetrafluoroborate showed a negative correlation. Data analysis was conducted in the R package mixtox, which integrates features such as curve fitting, experimental design, and mixture toxicity prediction. The international community of toxicologists is welcome to use this package and provide feedback as suggestions and comments. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bioavailability of Heavy Metals in Soil: Impact on Microbial Biodegradation of Organic Compounds and Possible Improvement Strategies

PubMed Central

Olaniran, Ademola O.; Balgobind, Adhika; Pillay, Balakrishna

2013-01-01

Co-contamination of the environment with toxic chlorinated organic and heavy metal pollutants is one of the major problems facing industrialized nations today. Heavy metals may inhibit biodegradation of chlorinated organics by interacting with enzymes directly involved in biodegradation or those involved in general metabolism. Predictions of metal toxicity effects on organic pollutant biodegradation in co-contaminated soil and water environments is difficult since heavy metals may be present in a variety of chemical and physical forms. Recent advances in bioremediation of co-contaminated environments have focussed on the use of metal-resistant bacteria (cell and gene bioaugmentation), treatment amendments, clay minerals and chelating agents to reduce bioavailable heavy metal concentrations. Phytoremediation has also shown promise as an emerging alternative clean-up technology for co-contaminated environments. However, despite various investigations, in both aerobic and anaerobic systems, demonstrating that metal toxicity hampers the biodegradation of the organic component, a paucity of information exists in this area of research. Therefore, in this review, we discuss the problems associated with the degradation of chlorinated organics in co-contaminated environments, owing to metal toxicity and shed light on possible improvement strategies for effective bioremediation of sites co-contaminated with chlorinated organic compounds and heavy metals. PMID:23676353

Dissolution of steel slags in aqueous media.

PubMed

Yadav, Shashikant; Mehra, Anurag

2017-07-01

Steel slag is a major industrial waste in steel industries, and its dissolution behavior in water needs to be characterized in the larger context of its potential use as an agent for sequestering CO 2 . For this purpose, a small closed system batch reactor was used to conduct the dissolution of steel slags in an aqueous medium under various dissolution conditions. In this study, two different types of steel slags were procured from steel plants in India, having diverse structural features, mineralogical compositions, and particle sizes. The experiment was performed at different temperatures for 240 h of dissolution at atmospheric pressure. The dissolution rates of major and minor slag elements were quantified through liquid-phase elemental analysis using an inductively coupled plasma atomic emission spectroscopy at different time intervals. Advanced analytical techniques such as field emission gun-scanning electron microscope, energy-dispersive X-ray, BET, and XRD were also used to analyze mineralogical and structural changes in the slag particles. High dissolution of slags was observed irrespective of the particle size distribution, which suggests high carbonation potential. Concentrations of toxic heavy metals in the leachate were far below maximum acceptable limits. Thus, the present study investigates the dissolution behavior of different mineral ions of steel slag in aqueous media in light of its potential application in CO 2 sequestration.

Injectable nanocarriers for biodetoxification

NASA Astrophysics Data System (ADS)

Leroux, Jean-Christophe

2007-11-01

Hospitals routinely treat patients suffering from overdoses of drugs or other toxic chemicals as a result of illicit drug consumption, suicide attempts or accidental exposures. However, for many life-threatening situations, specific antidotes are not available and treatment is largely based on emptying the stomach, administering activated charcoal or other general measures of intoxication support. A promising strategy for managing such overdoses is to inject nanocarriers that can extract toxic agents from intoxicated tissues. To be effective, the nanocarriers must remain in the blood long enough to sequester the toxic components and/or their metabolites, and the toxin bound complex must also remain stable until it is removed from the bloodstream. Here, we discuss the principles that govern the use of injectable nanocarriers in biodetoxification and review the pharmacological performance of a number of different approaches.

Quantitative assessment of atmospheric emissions of toxic heavy metals from anthropogenic sources in China: historical trend, spatial distribution, uncertainties, and control policies

NASA Astrophysics Data System (ADS)

Tian, H. Z.; Zhu, C. Y.; Gao, J. J.; Cheng, K.; Hao, J. M.; Wang, K.; Hua, S. B.; Wang, Y.; Zhou, J. R.

2015-09-01

Anthropogenic atmospheric emissions of typical toxic heavy metals have caused worldwide concern due to their adverse effects on human health and the ecosystem. By determining the best available representation of time-varying emission factors with S-shape curves, we establish the multiyear comprehensive atmospheric emission inventories of 12 typical toxic heavy metals (Hg, As, Se, Pb, Cd, Cr, Ni, Sb, Mn, Co, Cu, and Zn) from primary anthropogenic activities in China for the period of 1949-2012 for the first time. Further, we allocate the annual emissions of these heavy metals in 2010 at a high spatial resolution of 0.5° × 0.5° grid with ArcGIS methodology and surrogate indexes, such as regional population and gross domestic product (GDP). Our results show that the historical emissions of Hg, As, Se, Cd, Cr, Ni, Sb, Mn, Co, Cu, and Zn, during the period of 1949-2012, increased by about 22-128 times at an annual average growth rate of 5.1-8.0 %, reaching about 526.9-22 319.6 t in 2012. Nonferrous metal smelting, coal combustion of industrial boilers, brake and tyre wear, and ferrous metal smelting represent the dominant sources of heavy metal emissions. In terms of spatial variation, the majority of emissions are concentrated in relatively developed regions, especially for the northern, eastern, and southern coastal regions. In addition, because of the flourishing nonferrous metal smelting industry, several southwestern and central-southern provinces play a prominent role in some specific toxic heavy metals emissions, like Hg in Guizhou and As in Yunnan. Finally, integrated countermeasures are proposed to minimize the final toxic heavy metals discharge on account of the current and future demand of energy-saving and pollution reduction in China.

Phytoremediation: using green plants to clean up contaminate soil, groundwater, and wastewater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Negri, M.C.; Hinchman, R.R.; Gatliff, E.G.

1996-07-01

Phytoremediation, an emerging cleanup technology for contaminated soils, groundwater, and wastewater that is both low-tech and low-cost, is defined as the engineered use of green plants (including grasses, forbs, and woody species) to remove, contain, or render harmless such environmental contaminants as heavy metals, trace elements, organic compounds and radioactive compounds in soil or water. Our research includes a successful field demonstration of a plant bioreactor for processing the salty wastewater from petroleum wells; the demonstration is currently under way at a natural gas well site in Oklahoma, in cooperation with Devon Energy Corporation. A greenhouse experiment on zinc uptakemore » in hybrid poplar (Populus sp.) was initiated in 1995. These experiments are being conducted to confirm and extend field data indicating high levels of zinc (4,200 ppm) in leaves of hybrid poplar growing as a cleanup system at a site with zinc contamination in the root zone of some of the trees. Analyses of soil water from experimental pots that had received several doses of zinc indicated that the zinc was totally sequestered by the plants in about 4 hours during a single pass through the root system. The data also showed concentrations of sequestered metal of >38,000 ppm Zn in the dry root tissue. These levels of sequestered zinc exceed the levels found in either roots or tops of many of the known ``hyperaccumulator`` species. Because the roots sequester most of the contaminant taken up in most plants, a major objective of this program is to determine the feasibility of root harvesting as a method to maximize the removal of contaminants from soils. Available techniques and equipment for harvesting plant roots, including young tree roots, are being evaluated and modified as necessary for use with phytoremediation plants.« less

Selective sorption of lead, cadmium and zinc ions by a polymeric cation exchanger containing nano-Zr(HPO3S)2.

PubMed

Zhang, Qingrui; Pan, Bingcai; Pan, Bingjun; Zhang, Weiming; Jia, Kun; Zhang, Quanxing

2008-06-01

A novel polymeric hybrid sorbent, namely ZrPS-001, was fabricated for enhanced sorption of heavy metal ions by impregnating Zr(HPO3S)2 (i.e., ZrPS) nanoparticles within a porous polymeric cation exchanger D-001. The immobilized negatively charged groups bound to the polymeric matrix D-001 would result in preconcentration and permeation enhancement of target metal ions prior to sequestration, and ZrPS nanoparticles are expected to sequester heavy metals selectively through an ion-exchange process. Highly effective sequestration of lead, cadmium, and zinc ions from aqueous solution can be achieved by ZrPS-001 even in the presence of competing calcium ion at concentration several orders of magnitude greater than the target species. The exhausted ZrPS-001 beads are amenable to regeneration with 6 M HCI solution for repeated use without any significant capacity loss. Fixed-bed column treatment of simulated waters containing heavy metals at high or trace levels was also performed. The content of heavy metals in treated effluent approached or met the WHO drinking water standard.

Heavy metal toxicity as a kill mechanism in impact caused mass extinctions

NASA Technical Reports Server (NTRS)

Wdowiak, T. J.; Davenport, S. A.; Jones, D. D.; Wdowiak, P.

1988-01-01

Heavy metals that are known to be toxic exist in carbonaceous chrondrites at abundances considerably in excess to that of the terrestrial crust. An impactor of relatively undifferentiated cosmic matter would inject into the terrestrial environment large quantities of toxic elements. The abundances of toxic metals found in the Allende CV carbonaceous chondrite and the ratio of meteoritic abundance to crustal abundance are: Cr, 3630 PPM, 30X; Co, 662 PPM, 23X; ni, 13300 PPm, 134X; se, 8.2 PPM, 164X; Os, 0.828 PPM, 166X. The resulting areal density for global dispersal of impactor derived heavy metals and their dilution with terrestrial ejecta are important factors in the determination of the significance of impactor heavy metal toxicity as a kill mechanism in impact caused mass extinctions. A 10 km-diameter asteroid having a density of 3 gram per cu cm would yield a global areal density of impact dispersed chondritic material of 3 kg per square meter. The present areal density of living matter on the terrestrial land surface is 1 kg per square meter. Dilution of impactor material with terrestrial ejecta is determined by energetics, with the mass of ejecta estimated to be in the range of 10 to 100 times that of the mass of the impactor. Because a pelagic impact would be the most likely case, the result would be a heavy metal rainout.

Probiotic Lactobacillus rhamnosus Reduces Organophosphate Pesticide Absorption and Toxicity to Drosophila melanogaster.

PubMed

Trinder, Mark; McDowell, Tim W; Daisley, Brendan A; Ali, Sohrab N; Leong, Hon S; Sumarah, Mark W; Reid, Gregor

2016-10-15

Organophosphate pesticides used in agriculture can pose health risks to humans and wildlife. We hypothesized that dietary supplementation with Lactobacillus, a genus of commensal bacteria, would reduce absorption and toxicity of consumed organophosphate pesticides (parathion and chlorpyrifos [CP]). Several Lactobacillus species were screened for toleration of 100 ppm of CP or parathion in MRS broth based on 24-h growth curves. Certain Lactobacillus strains were unable to reach stationary-phase culture maxima and displayed an abnormal culture morphology in response to pesticide. Further characterization of commonly used, pesticide-tolerant and pesticide-susceptible, probiotic Lactobacillus rhamnosus strain GG (LGG) and L. rhamnosus strain GR-1 (LGR-1), respectively, revealed that both strains could significantly sequester organophosphate pesticides from solution after 24-h coincubations. This effect was independent of metabolic activity, as L. rhamnosus GG did not hydrolyze CP and no difference in organophosphate sequestration was observed between live and heat-killed strains. Furthermore, LGR-1 and LGG reduced the absorption of 100 μM parathion or CP in a Caco-2 Transwell model of the small intestine epithelium. To determine the effect of sequestration on acute toxicity, newly eclosed Drosophila melanogaster flies were exposed to food containing 10 μM CP with or without supplementation with live LGG. Supplementation with LGG simultaneously, but not with administration of CP 3 days prior (prophylactically), mitigated CP-induced mortality. In summary, the results suggest that L. rhamnosus may be useful for reducing toxic organophosphate pesticide exposure via passive binding. These findings could be transferable to clinical and livestock applications due to affordability and practical ability to supplement products with food-grade bacteria. The consequences of environmental pesticide pollution due to widespread usage in agriculture and soil leaching are becoming a major societal concern. Although the long-term effects of low-dose pesticide exposure for humans and wildlife remain largely unknown, logic suggests that these chemicals are not aligned with ecosystem health. This observation is most strongly supported by the agricultural losses associated with honeybee population declines, known as colony collapse disorder, in which pesticide usage is a likely trigger. Lactobacilli are bacteria used as beneficial microorganisms in fermented foods and have shown potentials to sequester and degrade environmental toxins. This study demonstrated that commonly used probiotic strains of lactobacilli could sequester, but not metabolize, organophosphate pesticides (parathion and chlorpyrifos). This Lactobacillus-mediated sequestration was associated with decreased intestinal absorption and insect toxicity in appropriate models. These findings hold promise for supplementing human, livestock, or apiary foods with probiotic microorganisms to reduce organophosphate pesticide exposure. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Risk assessment of heavy metals from combustion of pelletized municipal sewage sludge.

PubMed

Xiao, Zhihua; Yuan, Xingzhong; Leng, Lijian; Jiang, Longbo; Chen, Xiaohong; Zhibin, Wu; Xin, Peng; Jiachao, Zhang; Zeng, Guangming

2016-02-01

Fly ash and slag are important by-products obtained from combustion of municipal sewage sludge (MSS) after pelletization. The quantitative environmental impact assessment of heavy metals in fly ash and slag, compared to MSS, were performed in accordance with bioavailability and eco-toxicity, geo-accumulation index (GAI), risk assessment code (RAC), and potential ecological risk index (PERI). The results demonstrated that not only direct but also long-term bioavailability and eco-toxicity of heavy metals in fly ash and slag decreased except direct bioavailability and eco-toxicity of Pb in fly ash. The GAI demonstrated that combustion significantly weakened (P < 0.05) the pollution levels of heavy metals. PERI indicated that all risks attributed to heavy metals were significantly lowered (P < 0.05) from 777.07 (very high risk) in MSS to 288.72 (moderate risk) and 64.55 (low risk) in fly ash and slag, respectively. In terms of the RAC, seven heavy metals had low even no risk to the environments after combustion besides As in slag. The environmental risk of heavy metals in fly ash and slag was decreased compared with MSS. However, the results of PERI showed that fly ash had a moderate risk.

Effects of heavy metals on sea urchin embryo development. Part 2. Interactive toxic effects of heavy metals in synthetic mine effluents.

PubMed

Kobayashi, Naomasa; Okamura, Hideo

2005-12-01

Interactive toxic effects between heavy metals were investigated using a sea urchin (Anthocidaris crassispina) bioassay. An effluent from an abandoned mine showed significant inhibitory effects on embryo development as well as producing specific malformations. The effects on the embryos were reproduced by synthetic polluted seawater consisting of eight metals (manganese, lead, cadmium, nickel, zinc, chromium, iron, and copper) at the concentrations detected in the mine effluent. This indicated that the heavy metals were responsible for the effects observed. Five heavy metals were ranked in decreasing order of toxicity as follows: Cu>Zn>Pb>Fe>Mn. Among these, zinc and manganese could cause malformation of the embryos. From bioassay results using 27 combinations of heavy metals, 16 combinations including zinc could produce specific malformations, such as radialized, exo-gastrulal, and spaceship Apollo-like gastrulal embryos. Zinc was one of the elements responsible for causing malformations and its effects were intensified by the presence of the other metals, such as manganese, lead, iron, and copper.

Heavy Metal Tolerance in Plants: Role of Transcriptomics, Proteomics, Metabolomics, and Ionomics

PubMed Central

Singh, Samiksha; Parihar, Parul; Singh, Rachana; Singh, Vijay P.; Prasad, Sheo M.

2016-01-01

Heavy metal contamination of soil and water causing toxicity/stress has become one important constraint to crop productivity and quality. This situation has further worsened by the increasing population growth and inherent food demand. It has been reported in several studies that counterbalancing toxicity due to heavy metal requires complex mechanisms at molecular, biochemical, physiological, cellular, tissue, and whole plant level, which might manifest in terms of improved crop productivity. Recent advances in various disciplines of biological sciences such as metabolomics, transcriptomics, proteomics, etc., have assisted in the characterization of metabolites, transcription factors, and stress-inducible proteins involved in heavy metal tolerance, which in turn can be utilized for generating heavy metal-tolerant crops. This review summarizes various tolerance strategies of plants under heavy metal toxicity covering the role of metabolites (metabolomics), trace elements (ionomics), transcription factors (transcriptomics), various stress-inducible proteins (proteomics) as well as the role of plant hormones. We also provide a glance of some strategies adopted by metal-accumulating plants, also known as “metallophytes.” PMID:26904030

Toxic Metal Pollution in Pakistan and Its Possible Risks to Public Health.

PubMed

Shakir, Shakirullah Khan; Azizullah, Azizullah; Murad, Waheed; Daud, Muhammad K; Nabeela, Farhat; Rahman, Hazir; Ur Rehman, Shafiq; Häder, Donat-Peter

Environmental pollution has increased many folds in recent years and in some places has reached levels that are toxic to living things. Among pollutant types, toxic heavy metals and metalloids are among the chemicals that pose the highest threat to biological systems (Jjemba 2004). Unlike organic pollutants, which are biodegradable, heavy metals are not degraded into less hazardous end products (Gupta et al. 2001). Low concentrations of some heavy metals are essential for life, but some of them like Hg, As, Pb and Cd are biologically non-essential and very toxic to living organisms. Even the essential metals may become toxic if they are present at a concentration above the permissible level (Puttaiah and Kiran 2008). For example, exposure to Zn and Fe oxides produce gastric disorder and vomiting, irritation of the skin and mucous membranes. Intake of Ni, Cr, Pb, Cd and Cu causes heart problems, leukemia and cancer, while Co and Mg can cause anemia and hypertension (Drasch et al. 2006). Similarly, various studies indicated that overexposure to heavy metals in air can cause cardiovascular disorders (Miller et al. 2007; Schwartz 2001), asthma (Wiwatanadate and Liwsrisakun 2011), bronchitis/emphysema (Pope 2000), and other respiratory diseases (Dominici et al. 2006).

Mutant Huntingtin Impairs Axonal Trafficking in Mammalian Neurons In Vivo and In Vitro

PubMed Central

Trushina, Eugenia; Dyer, Roy B.; Badger, John D.; Ure, Daren; Eide, Lars; Tran, David D.; Vrieze, Brent T.; Legendre-Guillemin, Valerie; McPherson, Peter S.; Mandavilli, Bhaskar S.; Van Houten, Bennett; Zeitlin, Scott; McNiven, Mark; Aebersold, Ruedi; Hayden, Michael; Parisi, Joseph E.; Seeberg, Erling; Dragatsis, Ioannis; Doyle, Kelly; Bender, Anna; Chacko, Celin; McMurray, Cynthia T.

2004-01-01

Recent data in invertebrates demonstrated that huntingtin (htt) is essential for fast axonal trafficking. Here, we provide direct and functional evidence that htt is involved in fast axonal trafficking in mammals. Moreover, expression of full-length mutant htt (mhtt) impairs vesicular and mitochondrial trafficking in mammalian neurons in vitro and in whole animals in vivo. Particularly, mitochondria become progressively immobilized and stop more frequently in neurons from transgenic animals. These defects occurred early in development prior to the onset of measurable neurological or mitochondrial abnormalities. Consistent with a progressive loss of function, wild-type htt, trafficking motors, and mitochondrial components were selectively sequestered by mhtt in human Huntington's disease-affected brain. Data provide a model for how loss of htt function causes toxicity; mhtt-mediated aggregation sequesters htt and components of trafficking machinery leading to loss of mitochondrial motility and eventual mitochondrial dysfunction. PMID:15340079

Attenuation of Vibrio fischeri quorum sensing using rationally designed polymers.

PubMed

Piletska, Elena V; Stavroulakis, Georgios; Karim, Kal; Whitcombe, Michael J; Chianella, Iva; Sharma, Anant; Eboigbodin, Kevin E; Robinson, Gary K; Piletsky, Sergey A

2010-04-12

A first attempt to attenuate the quorum sensing (QS) of a marine heterotroph microorganism, Vibrio fischeri , using signal molecule-sequestering polymers (SSPs) is presented. A set of rationally designed polymers with affinity toward a signal molecule of V. fischeri , N-(beta-ketocaproyl)-l-homoserine lactone (3-oxo-C6-AHL) was produced. It is reported that computationally designed polymers could sequester a signal molecule of V. fischeri and prevent QS-controlled phenotypes (in this case, bioluminescence) from being up-regulated. It was proven that the attenuation of bioluminescence of V. fischeri was due to sequestration of the signal molecule by specific polymers and not due to the toxicity of polymer or nonspecific depletion of nutrients. The ability to disrupt the bacterial communication using easy to synthesize and chemically inert polymers could provide a new concept for the development of pharmaceuticals and susceptible device coatings such as catheters.

Risk Assessment of Heavy Metals Contamination in Paddy Soil, Plants, and Grains (Oryza sativa L.) at the East Coast of India

PubMed Central

Satpathy, Deepmala; Reddy, M. Vikram; Dhal, Soumya Prakash

2014-01-01

Heavy metals known to be accumulated in plants adversely affect human health. This study aims to assess the effects of agrochemicals especially chemical fertilizers applied in paddy fields, which release potential toxic heavy metals into soil. Those heavy metals get accumulated in different parts of paddy plant (Oryza sativa L.) including the grains. Concentrations of nonessential toxic heavy metals (Cd, Cr, and Pb) and the micronutrients (Cu, Mn, and Zn) were measured in the paddy field soil and plant parts. Mn and Cd are found to be accumulated more in shoot than in root. The metal transfer factors from soil to rice plant were significant for Pb, Cd, Cu, Cr, Mn, and Zn. The ranking order of bioaccumulation factor (BAF) for heavy metals was Zn > Mn > Cd > Cu > Cr > Pb indicating that the accumulation of micronutrients was more than that of nonessential toxic heavy metals. The concentrations of heavy metals were found to be higher in paddy field soils than that of the nearby control soil but below permissible limits. The higher Health Index (HI) values of rice consuming adults (1.561) and children (1.360) suggest their adverse health effects in the near future. PMID:24995308

Determination of heavy metals in the ambient atmosphere.

PubMed

Suvarapu, Lakshmi Narayana; Baek, Sung-Ok

2017-01-01

Heavy metal determination in ambient air is an important task for environmental researchers because of their toxicity to human beings. Some heavy metals (hexavalent chromium (Cr), arsenic (As), cadmium (Cd) and nickel (Ni)) have been listed as carcinogens. Furthermore, heavy metals in the atmosphere can accumulate in various plants and animals and enter humans through the food chain. This article reviews the determination of heavy metals in the atmosphere in different areas of the world since 2006. The results showed that most researchers concentrated on toxic metals, such as Cr, Cd, Ni, As and lead. A few studies used plant materials as bio-monitors for the atmospheric levels of heavy metals. Some researchers found higher concentrations of heavy metals surrounding industrial areas compared with residential and/or commercial areas. Most studies reported the major sources of the particulate matter and heavy metals in the atmosphere to be industrial emissions, vehicular emissions and secondary aerosols.

Seed chemistry of Sophora chrysophylla (mamane) in relation to diet of specialist avian seed predator Loxioides bailleui (palila) in Hawaii

USGS Publications Warehouse

Banko, P.C.; Cipollini, M.L.; Breton, G.W.; Paulk, E.; Wink, M.; Izhaki, Ido

2002-01-01

This study describes the chemical ecology of a tritrophic interaction among species endemic to the island of Hawaii, USA: a tree (Sophora chrysophylla: mamane), an endangered bird (Loxioides bailleui; palila), and moth larvae (Cydia spp.). Palila and Cydia both specialize on the seed embryos of mamane but avoid eating the seed coats. Palila actively seek out and feed mamane embryos and Cydia larvae to their nestlings. Because mamane embryos contain potentially toxic levels of alkaloids, including broadly toxic quinolizidine alkaloids, and because insects often sequester alkaloids from their food plants, we focus on the questions of why palila forage upon mamane embryos and why they supplement their diet with Cydia larvae. Our data show that mamane embryos contain high amounts of potentially toxic alkaloids, but are well balanced nutritionally and contain lipids, carbohydrates, proteins, amino acids, and minerals at levels that are likely to be sufficient for maintenance and breeding. Mamane seed coats contain lower levels of alkaloids and nutrients, somewhat higher levels of phenolics, and much higher levels of nondigestible fiber. Taken together, these results suggest that palila have evolved tolerance to high levels of alkaloids and that they forage upon embryos primarily because of their availability in the habitat and high nutritional reward. Our data also suggest that Cydia are used by palila because they are readily accessible, nontoxic, and nutritious; the larvae apparently do not sequester alkaloids while feeding upon mamane seeds. Our results are interpreted with respect to the likelihood of current and historical coadaptive responses in this ecologically isolated and simplified island setting.

Protective actions of the vesicular monoamine transporter 2 (VMAT2) in monoaminergic neurons.

PubMed

Guillot, Thomas S; Miller, Gary W

2009-04-01

Vesicular monoamine transporters (VMATs) are responsible for the packaging of neurotransmitters such as dopamine, serotonin, norepinephrine, and epinephrine into synaptic vesicles. These proteins evolved from precursors in the major facilitator superfamily of transporters and are among the members of the toxin extruding antiporter family. While the primary function of VMATs is to sequester neurotransmitters within vesicles, they can also translocate toxicants away from cytosolic sites of action. In the case of dopamine, this dual role of VMAT2 is combined-dopamine is more readily oxidized in the cytosol where it can cause oxidative stress so packaging into vesicles serves two purposes: neurotransmission and neuroprotection. Furthermore, the deleterious effects of exogenous toxicants on dopamine neurons, such as MPTP, can be attenuated by VMAT2 activity. The active metabolite of MPTP can be kept within vesicles and prevented from disrupting mitochondrial function thereby sparing the dopamine neuron. The highly addictive drug methamphetamine is also neurotoxic to dopamine neurons by using dopamine itself to destroy the axon terminals. Methamphetamine interferes with vesicular sequestration and increases the production of dopamine, escalating the amount in the cytosol and leading to oxidative damage of terminal components. Vesicular transport seems to resist this process by sequestering much of the excess dopamine, which is illustrated by the enhanced methamphetamine neurotoxicity in VMAT2-deficient mice. It is increasingly evident that VMAT2 provides neuroprotection from both endogenous and exogenous toxicants and that while VMAT2 has been adapted by eukaryotes for synaptic transmission, it is derived from phylogenetically ancient proteins that originally evolved for the purpose of cellular protection.

Modifications to toxic CUG RNAs induce structural stability, rescue mis-splicing in a myotonic dystrophy cell model and reduce toxicity in a myotonic dystrophy zebrafish model

DOE PAGES

deLorimier, Elaine; Coonrod, Leslie A.; Copperman, Jeremy; ...

2014-10-10

In this study, CUG repeat expansions in the 3' UTR of dystrophia myotonica protein kinase ( DMPK) cause myotonic dystrophy type 1 (DM1). As RNA, these repeats elicit toxicity by sequestering splicing proteins, such as MBNL1, into protein–RNA aggregates. Structural studies demonstrate that CUG repeats can form A-form helices, suggesting that repeat secondary structure could be important in pathogenicity. To evaluate this hypothesis, we utilized structure-stabilizing RNA modifications pseudouridine (Ψ) and 2'-O-methylation to determine if stabilization of CUG helical conformations affected toxicity. CUG repeats modified with Ψ or 2'-O-methyl groups exhibited enhanced structural stability and reduced affinity for MBNL1. Molecularmore » dynamics and X-ray crystallography suggest a potential water-bridging mechanism for Ψ-mediated CUG repeat stabilization. Ψ modification of CUG repeats rescued mis-splicing in a DM1 cell model and prevented CUG repeat toxicity in zebrafish embryos. This study indicates that the structure of toxic RNAs has a significant role in controlling the onset of neuromuscular diseases.« less

Applicability of agricultural waste and by-products for adsorptive removal of heavy metals from wastewater.

PubMed

Nguyen, T A H; Ngo, H H; Guo, W S; Zhang, J; Liang, S; Yue, Q Y; Li, Q; Nguyen, T V

2013-11-01

This critical review discusses the potential use of agricultural waste based biosorbents (AWBs) for sequestering heavy metals in terms of their adsorption capacities, binding mechanisms, operating factors and pretreatment methods. The literature survey indicates that AWBs have shown equal or even greater adsorption capacities compared to conventional adsorbents. Thanks to modern molecular biotechnologies, the roles of functional groups in biosorption process are better understood. Of process factors, pH appears to be the most influential. In most cases, chemical pretreatments bring about an obvious improvement in metal uptake capacity. However, there are still several gaps, which require further investigation, such as (i) searching for novel, multi-function AWBs, (ii) developing cost-effective modification methods and (iii) assessing AWBs under multi-metal and real wastewater systems. Once these challenges are settled, the replacement of traditional adsorbents by AWBs in decontaminating heavy metals from wastewater can be expected in the future. Copyright © 2013 Elsevier Ltd. All rights reserved.

Toxicity, mechanism and health effects of some heavy metals

PubMed Central

Jaishankar, Monisha; Tseten, Tenzin; Anbalagan, Naresh; Beeregowda, Krishnamurthy N.

2014-01-01

Heavy metal toxicity has proven to be a major threat and there are several health risks associated with it. The toxic effects of these metals, even though they do not have any biological role, remain present in some or the other form harmful for the human body and its proper functioning. They sometimes act as a pseudo element of the body while at certain times they may even interfere with metabolic processes. Few metals, such as aluminium, can be removed through elimination activities, while some metals get accumulated in the body and food chain, exhibiting a chronic nature. Various public health measures have been undertaken to control, prevent and treat metal toxicity occurring at various levels, such as occupational exposure, accidents and environmental factors. Metal toxicity depends upon the absorbed dose, the route of exposure and duration of exposure, i.e. acute or chronic. This can lead to various disorders and can also result in excessive damage due to oxidative stress induced by free radical formation. This review gives details about some heavy metals and their toxicity mechanisms, along with their health effects. PMID:26109881

Spatial Evaluation of Heavy Metals Concentrations in the Surface Sediment of Taihu Lake.

PubMed

Niu, Yong; Jiao, Wei; Yu, Hui; Niu, Yuan; Pang, Yong; Xu, Xiangyang; Guo, Xiaochun

2015-11-27

With regard to the size of China's freshwater lakes, Taihu Lake ranks third and it plays an important role in the supply of drinking water, flood prevention, farming and navigation, as well as in the travelling industry. The problem of environmental pollution has attracted widespread attention in recent years. In order to understand the levels, distribution and sources of heavy metals in sediments of Taihu Lake, random selection was carried out to obtain 59 samples of surface sediment from the entire lake and study the concentrations of Pb, Cd, Cu, Zn, Cr and Ni. Toxic units were also calculated to normalize the toxicities caused by various heavy metals. As a result, Cd and Cu in sediment were considered lower than the effect range low (ERL) at all regions where samples were gathered, while Pb and Ni were categorized into ERL-effect range median (ERM) at over 22% of the regions where samples were obtained. Nevertheless, all average concentrations of the samples were below the level of potential effect. According to the findings of this research, significant spatial heterogeneity existed in the above heavy metals. In conclusion, the distribution areas of heavy metals with higher concentrations were mainly the north bays, namely Zhushan Bay, Meiliang Bay as well as Gonghu Bay. The distribution areas of Cu, Zn, Cr and Ni with higher concentration also included the lake's central region, whereas the uniform distribution areas of those with lower concentrations were the lake's southeast region. In addition, it was most probable that the spatial distribution of heavy metals was determined by river inputs, whereas atmospheric precipitation caused by urban and traffic contamination also exerted considerable effects on the higher concentrations of Pb and Cd. Through evaluating the total amount of toxic units (ΣTU), it was found that higher toxicity existed primarily in the north bays and central region of the lake. If the heavy metals were sorted by the reduction of mean heavy metal toxic units in Taihu Lake in descending order, it would be Pb, Cr, Ni, Cd, Zn and Cu. Generally speaking, these result of analyses are conducive to alleviating the contamination of heavy metals in Taihu Lake.

Application of a bacterial whole cell biosensor for the rapid detection of cytotoxicity in heavy metal contaminated seawater.

PubMed

Cui, Zhisong; Luan, Xiao; Jiang, Huichao; Li, Qian; Xu, Guangfei; Sun, Chengjun; Zheng, Li; Song, Yizhi; Davison, Paul A; Huang, Wei E

2018-06-01

A toxicity biosensor Acinetobacter baylyi Tox2 was constructed with the host strain A. baylyi ADP1 harboring a new and medium-copy-number plasmid pWH1274_lux, and was applied to detect the cytotoxicity of heavy metal contaminated seawater. The gene cassette luxCDABE was controlled by constitutively expressed promoter P tet on pWH1274_lux and the bioluminescence intensity of the biosensor reduces in proportional to the concentrations of toxic compounds. A. baylyi Tox2 exhibits tolerance to salinity, hence it is applicable to seawater samples. A. baylyi Tox2 and Mugilogobius chulae were exposed to different concentrations of heavy metals (Hg 2+ , Zn 2+ , Cu 2+ , and Cd 2+ ) in artificial seawater for performance comparison and Pearson correlation analysis showed a significant correlation (p < 0.01) between A. baylyi Tox2 toxicity detection and the fish (M. chulae) exposure test. This suggests that the performance of A. baylyi Tox2 is comparable to the conventional fish toxicity test in terms of cytotoxicity detection of heavy metal contaminated seawater. Furthermore, A. baylyi Tox2 was used to evaluate cytotoxicity of field-collected seawater samples. The results indicate that there was a significant correlation between the luminescence inhibition ratio (IR) of A. baylyi Tox2 and heavy metal concentrations detected by ICP-MS in the samples. Two seawater samples, which contained a high concentration of total heavy metals, exhibited stronger cytotoxicity than the samples containing low concentrations of heavy metals. In conclusion, A. baylyi Tox2 can be used as an alternative tool to aquatic animals for the evaluation of the cytotoxicity of heavy metal contamination in the marine environment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Genetic and Biochemical Analysis of High Iron Toxicity in Yeast

PubMed Central

Lin, Huilan; Li, Liangtao; Jia, Xuan; Ward, Diane McVey; Kaplan, Jerry

2011-01-01

Iron storage in yeast requires the activity of the vacuolar iron transporter Ccc1. Yeast with an intact CCC1 are resistant to iron toxicity, but deletion of CCC1 renders yeast susceptible to iron toxicity. We used genetic and biochemical analysis to identify suppressors of high iron toxicity in Δccc1 cells to probe the mechanism of high iron toxicity. All genes identified as suppressors of high iron toxicity in aerobically grown Δccc1 cells encode organelle iron transporters including mitochondrial iron transporters MRS3, MRS4, and RIM2. Overexpression of MRS3 suppressed high iron toxicity by decreasing cytosolic iron through mitochondrial iron accumulation. Under anaerobic conditions, Δccc1 cells were still sensitive to high iron toxicity, but overexpression of MRS3 did not suppress iron toxicity and did not result in mitochondrial iron accumulation. We conclude that Mrs3/Mrs4 can sequester iron within mitochondria under aerobic conditions but not anaerobic conditions. We show that iron toxicity in Δccc1 cells occurred under both aerobic and anaerobic conditions. Microarray analysis showed no evidence of oxidative damage under anaerobic conditions, suggesting that iron toxicity may not be solely due to oxidative damage. Deletion of TSA1, which encodes a peroxiredoxin, exacerbated iron toxicity in Δccc1 cells under both aerobic and anaerobic conditions, suggesting a unique role for Tsa1 in iron toxicity. PMID:21115478

Heavy Metals in ToxCast: Relevance to Food Safety (SOT) ...

EPA Pesticide Factsheets

Human exposure to heavy metals occurs through food contamination due to industrial processes, vehicle emissions and farming methods. Specific toxicity endpoints have been associated with metal exposures, e.g. lead and neurotoxicity; however, numerous varieties of heavy metals have not been systematically examined for potential toxicities. We describe results from testing a large set of heavy metal-containing compounds in extensive suites of in vitro assays to suggest possible molecular initiating events in toxicity pathways. A broad definition of heavy metals that includes As, Se and organometallics or inorganic salts containing metals in Group III or higher (MW > 40) was used to identify 75 different compounds tested in the EPA’s ToxCast assays encompassing biochemical, cellular and model organism assays. These 75, plus an additional 100 metal-containing compounds, were tested in Tox21 quantitative high-throughput screening (qHTS) assays covering nuclear receptor and stress pathways. Known activities were confirmed such as activation of stress pathways and nuclear receptors (RXR, PPARg) as well as overt cytotoxicity. Specifically, organotin and organomercury were among the most potent of over 8K chemicals tested. The HTS results support known toxicities, including promiscuous GPCR activity for mercury compounds consistent with the neuropsychiatric effects seen in mercury poisoning (Mad Hatter’s Syndrome). As such, HTS approaches provide an efficient method

Regulation of tolerance of Chlamydomonas reinhardtii to heavy metal toxicity by heme oxygenase-1 and carbon monoxide.

PubMed

Wei, Yuan Yuan; Zheng, Qi; Liu, Zhao Pu; Yang, Zhi Min

2011-09-01

Investigation of heavy metal tolerance genes in green algae is of great importance because heavy metals have become one of the major contaminants in the aquatic ecosystem. In plants, accumulation of heavy metals modifies many aspects of cellular functions. However, the mechanism by which heavy metals exert detrimental effects is poorly understood. In this study, we identified a role for HO-1 (encoding heme oxygenase-1) in regulating the response of Chlamydomonas reinhardtii, a unicellular green alga, to mercury (Hg). Transgenic algae overexpressing HO-1 showed high tolerance to Hg exposure, with a 48.2% increase in cell number over the wild type, but accumulated less Hg. Physiological analysis revealed that expression of HO-1 suppressed the Hg-induced generation of reactive oxygen species. We further identified the effect of carbon monoxide (CO), a product of HO-1-mediated heme degradation, on growth and physiological parameters. Interestingly, administration of exogenous CO at non-toxic levels also conferred the tolerance of algae to Hg exposure. The CO-mediated alleviation of Hg toxicity was closely related to the lower accumulation of Hg and free radical species. These results indicate that functional identification of HO-1 is useful for molecular breeding designed to improve plant tolerance to heavy metals and reduce heavy metal accumulation in plant cells.

Effects of multi-metal toxicity on the performance of sewage treatment system during the festival of colors (Holi) in India.

PubMed

Tyagi, Vinay Kumar; Bhatia, Akanksha; Gaur, Rubia Zahid; Khan, Abid Ali; Ali, Muntajir; Khursheed, Anwar; Kazmi, Absar Ahmad

2012-12-01

The present study investigated the effects of heavy metals (Ni, Zn, Cd, Cu, and Pb) toxicity on the performance of 18 MLD activated sludge process-based sewage treatment plant (STP) during celebration of Holi (festival of colors in India). The composite sampling (n = 32) was carried out during the entire study period. The findings show a significant decrease in chemical oxygen demand removal efficiency (20%) of activated sludge system, after receiving the heavy metals laden wastewater. A significant reduction of 40% and 60% were observed in MLVSS/MLSS ratio and specific oxygen uptake rate, which eventually led to a substantial decrease in biomass growth yield (from 0.54 to 0.17). The toxic effect of metals ions was also observed on protozoan population. Out of the 12 mixed liquor species recorded, only two ciliates species of Vorticella and Epistylis exhibited the greater tolerance against heavy metals toxicity. Furthermore, activated sludge shows the highest metal adsorption affinity for Cu, followed by Zn, Pb, Ni, and Cd (Cu > Zn > Pb > Ni > Cd). Finally, this study proves the robustness of activated sludge system against the sudden increase in heavy metal toxicity since it recovered the earlier good quality performance within 5 days.

Microbial and Plant-Assisted Bioremediation of Heavy Metal Polluted Environments: A Review

PubMed Central

Ojuederie, Omena Bernard

2017-01-01

Environmental pollution from hazardous waste materials, organic pollutants and heavy metals, has adversely affected the natural ecosystem to the detriment of man. These pollutants arise from anthropogenic sources as well as natural disasters such as hurricanes and volcanic eruptions. Toxic metals could accumulate in agricultural soils and get into the food chain, thereby becoming a major threat to food security. Conventional and physical methods are expensive and not effective in areas with low metal toxicity. Bioremediation is therefore an eco-friendly and efficient method of reclaiming environments contaminated with heavy metals by making use of the inherent biological mechanisms of microorganisms and plants to eradicate hazardous contaminants. This review discusses the toxic effects of heavy metal pollution and the mechanisms used by microbes and plants for environmental remediation. It also emphasized the importance of modern biotechnological techniques and approaches in improving the ability of microbial enzymes to effectively degrade heavy metals at a faster rate, highlighting recent advances in microbial bioremediation and phytoremediation for the removal of heavy metals from the environment as well as future prospects and limitations. However, strict adherence to biosafety regulations must be followed in the use of biotechnological methods to ensure safety of the environment. PMID:29207531

Microbial and Plant-Assisted Bioremediation of Heavy Metal Polluted Environments: A Review.

PubMed

Ojuederie, Omena Bernard; Babalola, Olubukola Oluranti

2017-12-04

Environmental pollution from hazardous waste materials, organic pollutants and heavy metals, has adversely affected the natural ecosystem to the detriment of man. These pollutants arise from anthropogenic sources as well as natural disasters such as hurricanes and volcanic eruptions. Toxic metals could accumulate in agricultural soils and get into the food chain, thereby becoming a major threat to food security. Conventional and physical methods are expensive and not effective in areas with low metal toxicity. Bioremediation is therefore an eco-friendly and efficient method of reclaiming environments contaminated with heavy metals by making use of the inherent biological mechanisms of microorganisms and plants to eradicate hazardous contaminants. This review discusses the toxic effects of heavy metal pollution and the mechanisms used by microbes and plants for environmental remediation. It also emphasized the importance of modern biotechnological techniques and approaches in improving the ability of microbial enzymes to effectively degrade heavy metals at a faster rate, highlighting recent advances in microbial bioremediation and phytoremediation for the removal of heavy metals from the environment as well as future prospects and limitations. However, strict adherence to biosafety regulations must be followed in the use of biotechnological methods to ensure safety of the environment.

76 FR 11980 - Stakeholder Input: Listening Session to Provide Information and Solicit Suggestions for...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-04

... organisms to the surrounding water. Coatings used to deter organism growth on vessel hulls can release heavy metals and/or other biocides, which can lead to acute or chronic toxicity in non-targeted organisms. Bilgewater can contain oils, dissolved heavy metals, and other chemical constituents that can result in toxic...

Treatment of acid rock drainage using a sulfate-reducing bioreactor with zero-valent iron.

PubMed

Ayala-Parra, Pedro; Sierra-Alvarez, Reyes; Field, James A

2016-05-05

This study assessed the bioremediation of acid rock drainage (ARD) in flow-through columns testing zero-valent iron (ZVI) for the first time as the sole exogenous electron donor to drive sulfate-reducing bacteria in permeable reactive barriers. Columns containing ZVI, limestone or a mixture of both materials were inoculated with an anaerobic mixed culture and fed a synthetic ARD containing sulfuric acid and heavy metals (initially copper, and later also cadmium and lead). ZVI significantly enhanced sulfate reduction and the heavy metals were extensively removed (>99.7%). Solid-phase analyses showed that heavy metals were precipitated with biogenic sulfide in the columns packed with ZVI. Excess sulfide was sequestered by iron, preventing the discharge of dissolved sulfide. In the absence of ZVI, heavy metals were also significantly removed (>99.8%) due to precipitation with hydroxide and carbonate ions released from the limestone. Vertical-profiles of heavy metals in the columns packing, at the end of the experiment, demonstrated that the ZVI columns still had excess capacity to remove heavy metals, while the capacity of the limestone control column was approaching saturation. The ZVI provided conditions that enhanced sulfate reduction and generated alkalinity. Collectively, the results demonstrate an innovative passive ARD remediation process using ZVI as sole electron-donor. Copyright © 2016 Elsevier B.V. All rights reserved.

Impact of sediment characteristics on the heavy metal concentration and their ecological risk level of surface sediments of Vaigai river, Tamilnadu, India.

PubMed

Paramasivam, K; Ramasamy, V; Suresh, G

2015-02-25

The distributions of the metals (Al, Fe, Mg, Cd, Cr, Cu, Ni, Pb and Zn) were measured for the surface sediments of the Vaigai river, Tamilnadu, India. These values are compared with different standard values to assess the level of toxicity of the heavy metals in the sediments. Risk indices (CF, PLI and PER) are also calculated to understand the level of toxicity of the metals. Multivariate statistical analyses (Pearson's correlation analysis, cluster analysis and factor analysis) are carried out to know the inter-relationship between sediment characteristics and the heavy metals. From this analysis, it is confirmed that the contents of clay and organic matter play an important role to raise the level of heavy metal contents as well as PLI and PER (level of toxicity). Heavy metal concentrations of the samples (after removing silt and clay fractions from bulk samples) show decrease in their concentrations and risk indices compared to the level of bulk samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Kidney and heavy metals - The role of environmental exposure (Review).

PubMed

Lentini, Paolo; Zanoli, Luca; Granata, Antonio; Signorelli, Salvatore Santo; Castellino, Pietro; Dell'Aquila, Roberto

2017-05-01

Heavy metals are extensively used in agriculture and industrial applications such as production of pesticides, batteries, alloys, and textile dyes. Prolonged, intensive or excessive exposure can induce related systemic disorders. Kidney is a target organ in heavy metal toxicity for its capacity to filter, reabsorb and concentrate divalent ions. The extent and the expression of renal damage depends on the species of metals, the dose, and the time of exposure. Almost always acute kidney impairment differs from chronic renal failure in its mechanism and in the magnitude of the outcomes. As a result, clinical features and treatment algorithm are also different. Heavy metals in plasma exist in an ionized form, that is toxic and leads to acute toxicity and a bound, inert form when metal is conjugated with metallothionein and are then delivered to the liver and possible causing the kidney chronic damage. Treatment regimens include chelation therapy, supportive care, decontamination procedures and renal replacement therapies. This review adds specific considerations to kidney impairment due to the most common heavy metal exposures and its treatment.

DOE Office of Scientific and Technical Information (OSTI.GOV)

deLorimier, Elaine; Coonrod, Leslie A.; Copperman, Jeremy

In this study, CUG repeat expansions in the 3' UTR of dystrophia myotonica protein kinase ( DMPK) cause myotonic dystrophy type 1 (DM1). As RNA, these repeats elicit toxicity by sequestering splicing proteins, such as MBNL1, into protein–RNA aggregates. Structural studies demonstrate that CUG repeats can form A-form helices, suggesting that repeat secondary structure could be important in pathogenicity. To evaluate this hypothesis, we utilized structure-stabilizing RNA modifications pseudouridine (Ψ) and 2'-O-methylation to determine if stabilization of CUG helical conformations affected toxicity. CUG repeats modified with Ψ or 2'-O-methyl groups exhibited enhanced structural stability and reduced affinity for MBNL1. Molecularmore » dynamics and X-ray crystallography suggest a potential water-bridging mechanism for Ψ-mediated CUG repeat stabilization. Ψ modification of CUG repeats rescued mis-splicing in a DM1 cell model and prevented CUG repeat toxicity in zebrafish embryos. This study indicates that the structure of toxic RNAs has a significant role in controlling the onset of neuromuscular diseases.« less

Phytoremediation of Ionic and Methylmercury Pollution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richard Meagher

Phytoremediation is defined as the use of plants to extract, resist, detoxify, and/or sequester toxic environmental pollutants. The long-term goal of the proposed research is to develop and test highly productive, field-adapted plant species that have been engineered for the phytoremediation of mercury. A variety of different genes, which should enable plants to clean mercury polluted sites are being tested as tools for mercury phytoremediation, first in model laboratory plants and then in potential field species.

Review of heavy metal bio-remediation in contaminated freeway facilitated by adsorption

NASA Astrophysics Data System (ADS)

Zheng, Chaocheng

2017-08-01

Toxicity around biological systems is a significant issue for environmental health in a long term. Recent biotechnological approaches for bio-remediation of heavy metals in freeway frequently include mineralization, bio-adsorption or even remediation. Thus, adequate restoration in freeway requiring cooperation, integration and assimilation of such biotechnological advances along with traditional and ethical wisdom to unravel the mystery of nature in the emerging field of bio-remediation was reviewed with highlights to better understand problems associated with toxicity of heavy metals and eco-friendly technologies.

[Enrichment and toxicity effect of heavy metals in soil ecosystem].

PubMed

Wang, Zhenzhong; Zhang, Youmei; Deng, Jifu; Li, Zhongwu

2006-10-01

The study on the heavy metals-polluted soil of Qingshuitang District, Zhuzhou City showed that the main enriched heavy metals in the soil were Cd, Hg, As, Zn, Pb and Cu, among which, the former three had strong biotoxicity while the others had definite toxicity, with the average integrative pollution index being 6.40. The heavy metals enrichment in soil animals increased with increasing pollution degree. Especially for some species of Megascoiecidae, they had a high enrichment of Cd, with the enrichment index being 11.96. The species and quantity of soil animals decreased with increasing Cd concentration. Cd had an obvious biotoxic effect on Megsacoiecidae' s isozyme activity. The heavy metals enrichment in vegetables also increased with increasing pollution degree, but there existed obvious interspecies difference in Cd enrichment.

Modified composites based on mesostructured iron oxyhydroxide and synthetic minerals: a potential material for the treatment of various toxic heavy metals and its toxicity.

PubMed

Chung, Seung-Gun; Ryu, Jae-Chun; Song, Mi-Kyung; An, Byungryul; Kim, Song-Bae; Lee, Sang-Hyup; Choi, Jae-Woo

2014-02-28

The composites of mesostructured iron oxyhydroxide and/or commercial synthetic zeolite were investigated for use in the removal of toxic heavy metals, such as cadmium, copper, lead and arsenic, from aqueous solution. Four types of adsorbents, dried alginate beads (DABs), synthetic-zeolite impregnated beads (SZIBs), meso-iron-oxyhydroxide impregnated beads (MIOIBs) and synthetic-zeolite/meso-iron-oxyhydroxide composite beads (SZMIOIBs), were prepared for heavy metal adsorption tests. Laboratory experiments were conducted to investigate the removal efficiencies of cations and anions of heavy metals and the possibility of regenerating the adsorbents. Among these adsorbents, the MIOIBs can simultaneously remove cations and anions of heavy metals; they have high adsorption capacities for lead (60.1mgg(-1)) and arsenic (71.9mgg(-1)) compared with other adsorbents, such as DABs (158.1 and 0.0mgg(-1)), SZIB (42.9 and 0.0mgg(-1)) and SZMIOIB (54.0 and 5.9mgg(-1)) for lead and arsenic, respectively. Additionally, the removal efficiency was consistent at approximately 90%, notwithstanding repetitive regeneration. The characteristics of meso-iron-oxyhydroxide powder were confirmed by X-ray diffraction, Brunauer-Emmett-Teller and transmission electron microscopy. We also performed a comparative toxicity study that indicated that much lower concentrations of the powdered form of mesostructured iron oxyhydroxide had stronger cytotoxicity than the granular form. These results suggest that the granular form of meso iron oxyhydroxide is a more useful and safer adsorbent for heavy metal treatment than the powdered form. This research provides promising results for the application of MIOIBs as an adsorbent for various heavy metals from wastewater and sewage. Copyright © 2013 Elsevier B.V. All rights reserved.

Effect of temperature on heavy metal toxicity to juvenile crayfish, Orconectes immunis (Hagen).

PubMed

Khan, M A Q; Ahmed, S A; Catalin, Bogdon; Khodadoust, A; Ajayi, Oluwaleke; Vaughn, Mark

2006-10-01

The acute toxicity of four selected heavy metals to juvenile crayfish Orconectes immunis (Hagen) (1-2 g wet body wt. each) at room temperature increased in the following order: cadmium (x3) < copper (x10) < zinc (x2) < lead. The toxicity of these metals to crayfish acclimated at 17, 20, 23/24, and 27 degrees C increased with temperature (by 7-20% between 20 and 24 degrees C and 14-26% between 20 and 27 degrees C) as judged by the lowering of LT(50) (time to kill 50% of test animals at a fixed concentration) values. A 4 degrees C rise in temperature (from 20 to 24 degrees C), which increased the toxicity of copper by about 7%, increased the rate of oxygen consumption by about 34%. Heavy metals inhibited the rate of oxygen consumption at all temperatures. In 20 degrees C-acclimated crayfish, copper caused about 17% inhibition of oxygen consumption compared to about 7-12% by other metals including the most toxic cadmium. A 3-4 degrees C rise in temperature tripled the inhibitory effect of copper (20%), cadmium and zinc (26 and 18%, respectively), but not of lead, on oxygen consumption. A 7 degrees C-rise in temperature (from 20 to 27 degrees C) increased the inhibitory effect of heavy metals, including lead, on oxygen consumption by up to 54% in the case of copper. The data indicate that rising global temperatures (currently 0.60 degrees C) associated with climate change can have the potential to increase the sensitivity of aquatic animals to heavy metals in their environment.

A mouse model study of toxicity and biodistribution of a replication defective adenovirus serotype 5 virus with its genome engineered to contain a decoy hyper binding site to sequester and suppress oncogenic HMGA1 as a new cancer treatment therapy.

PubMed

Hassan, Faizule; Lossie, Sarah L; Kasik, Ellen P; Channon, Audrey M; Ni, Shuisong; Kennedy, Michael A

2018-01-01

The HGMA1 architectural transcription factor is highly overexpressed in many human cancers. Because HMGA1 is a hub for regulation of many oncogenes, its overexpression in cancer plays a central role in cancer progression and therefore HMGA1 is gaining increasing attention as a target for development of therapeutic approaches to suppress either its expression or action in cancer cells. We have developed the strategy of introducing decoy hyper binding sites for HMGA1 into the nucleus of cancer cells with the goal of competetively sequestering overexpressed HMGA1 and thus suppressing its oncogenic action. Towards achieving this goal, we have introduced an HMGA1 decoy hyper binding site composed of six copies of a high affinity HMGA1 binding site into the genome of the replication defective adenovirus serotype 5 genome and shown that the engineered virus effectively reduces the viability of human pancreatic and cancer cells. Here we report the first pre-clinical measures of toxicity and biodistribution of the engineered virus in C57BL/6J Black 6 mice. The immune response to exposure of the engineered virus was determined by assaying the serum levels of key cytokines, IL-6 and TNF-α. Toxicity due to exposure to the virus was determined by measuring the serum levels of the liver enzymes aspartate aminotransferase and alanine aminotransferase. Biodistribution was measured following direct injection into the pancreas or liver by quantifying viral loads in the pancreas, liver, spleen and brain.

Soluble forms of polyQ-expanded huntingtin rather than large aggregates cause endoplasmic reticulum stress

NASA Astrophysics Data System (ADS)

Leitman, Julia; Ulrich Hartl, F.; Lederkremer, Gerardo Z.

2013-11-01

In Huntington’s disease, as in other neurodegenerative diseases, it was initially thought that insoluble protein aggregates are the toxic species. However, growing evidence implicates soluble oligomeric polyglutamine-expanded huntingtin in cytotoxicity. Here we show that pathogenic huntingtin inhibits endoplasmic reticulum (ER)-associated degradation and induces ER stress before its aggregation into visible inclusions. All three branches of the unfolded protein response are activated. ER stress can be compensated by overexpression of p97/VCP, suggesting its sequestration by pathogenic huntingtin as a main cause. Stress correlates with the presence of huntingtin oligomers and is independent of continual huntingtin synthesis. Stress levels, measured in striatal neurons, are stabilized but only slowly subside on huntingtin aggregation into inclusions. Our results can be explained by the constant conversion of huntingtin monomers to toxic oligomers; large aggregates sequester the former, precluding further conversion, whereas pre-existing toxic oligomers are only gradually depleted.

Stormwater filtration of toxic heavy metal ions using lignocellulosic materials selection process, fiberization, chemical modification, and mat formation

Treesearch

James S. Han

1999-01-01

Lignocellulosic materials were evaluated for their effectiveness in filtering toxic heavy metals from stormwater. Kenaf, alfalfa, juniper, and aspen fibers were used as models to evaluate the effectiveness and limitations of chemical modification and the extent of fiber degradation. Individual and mixed aqueous solutions of nickel, copper, zinc, and cadmium in various...

Spatial Evaluation of Heavy Metals Concentrations in the Surface Sediment of Taihu Lake

PubMed Central

Niu, Yong; Jiao, Wei; Yu, Hui; Niu, Yuan; Pang, Yong; Xu, Xiangyang; Guo, Xiaochun

2015-01-01

With regard to the size of China’s freshwater lakes, Taihu Lake ranks third and it plays an important role in the supply of drinking water, flood prevention, farming and navigation, as well as in the travelling industry. The problem of environmental pollution has attracted widespread attention in recent years. In order to understand the levels, distribution and sources of heavy metals in sediments of Taihu Lake, random selection was carried out to obtain 59 samples of surface sediment from the entire lake and study the concentrations of Pb, Cd, Cu, Zn, Cr and Ni. Toxic units were also calculated to normalize the toxicities caused by various heavy metals. As a result, Cd and Cu in sediment were considered lower than the effect range low (ERL) at all regions where samples were gathered, while Pb and Ni were categorized into ERL-effect range median (ERM) at over 22% of the regions where samples were obtained. Nevertheless, all average concentrations of the samples were below the level of potential effect. According to the findings of this research, significant spatial heterogeneity existed in the above heavy metals. In conclusion, the distribution areas of heavy metals with higher concentrations were mainly the north bays, namely Zhushan Bay, Meiliang Bay as well as Gonghu Bay. The distribution areas of Cu, Zn, Cr and Ni with higher concentration also included the lake’s central region, whereas the uniform distribution areas of those with lower concentrations were the lake’s southeast region. In addition, it was most probable that the spatial distribution of heavy metals was determined by river inputs, whereas atmospheric precipitation caused by urban and traffic contamination also exerted considerable effects on the higher concentrations of Pb and Cd. Through evaluating the total amount of toxic units (ΣTU), it was found that higher toxicity existed primarily in the north bays and central region of the lake. If the heavy metals were sorted by the reduction of mean heavy metal toxic units in Taihu Lake in descending order, it would be Pb, Cr, Ni, Cd, Zn and Cu. Generally speaking, these result of analyses are conducive to alleviating the contamination of heavy metals in Taihu Lake. PMID:26633432

A cadmium-transporting P1B-type ATPase in yeast Saccharomyces cerevisiae.

PubMed

Adle, David J; Sinani, Devis; Kim, Heejeong; Lee, Jaekwon

2007-01-12

Detoxification and homeostatic acquisition of metal ions are vital for all living organisms. We have identified PCA1 in yeast Saccharomyces cerevisiae as an overexpression suppressor of copper toxicity. PCA1 possesses signatures of a P1B-type heavy metal-transporting ATPase that is widely distributed from bacteria to humans. Copper resistance conferred by PCA1 is not dependent on catalytic activity, but it appears that a cysteine-rich region located in the N terminus sequesters copper. Unexpectedly, when compared with two independent natural isolates and an industrial S. cerevisiae strain, the PCA1 allele of the common laboratory strains we have examined possesses a missense mutation in a predicted ATP-binding residue conserved in P1B-type ATPases. Consistent with a previous report that identifies an equivalent mutation in a copper-transporting P1B-type ATPase of a Wilson disease patient, the PCA1 allele found in laboratory yeast strains is nonfunctional. Overexpression or deletion of the functional allele in yeast demonstrates that PCA1 is a cadmium efflux pump. Cadmium as well as copper and silver, but not other metals examined, dramatically increase PCA1 protein expression through post-transcriptional regulation and promote subcellular localization to the plasma membrane. Our study has revealed a novel metal detoxification mechanism in yeast mediated by a P1B-type ATPase that is unique in structure, substrate specificity, and mode of regulation.

Microcin Amyloid Fibrils A Are Reservoir of Toxic Oligomeric Species

PubMed Central

Shahnawaz, Mohammad; Soto, Claudio

2012-01-01

Microcin E492 (Mcc), a low molecular weight bacteriocin produced by Klebsiella pneumoniae RYC492, has been shown to exist in two forms: soluble forms that are believed to be toxic to the bacterial cell by forming pores and non-toxic fibrillar forms that share similar biochemical and biophysical properties with amyloids associated with several human diseases. Here we report that fibrils polymerized in vitro from soluble forms sequester toxic species that can be released upon changing environmental conditions such as pH, ionic strength, and upon dilution. Our results indicate that basic pH (≥8.5), low NaCl concentrations (≤50 mm), and dilution (>10-fold) destabilize Mcc fibrils into more soluble species that are found to be toxic to the target cells. Additionally, we also found a similar conversion of non-toxic fibrils into highly toxic oligomers using Mcc aggregates produced in vivo. Moreover, the soluble protein released from fibrils is able to rapidly polymerize into amyloid fibrils under fibril-forming conditions and to efficiently seed aggregation of monomeric Mcc. Our findings indicate that fibrillar forms of Mcc constitute a reservoir of toxic oligomeric species that is released into the medium upon changing the environmental conditions. These findings may have substantial implications to understand the dynamic process of interconversion between toxic and non-toxic aggregated species implicated in protein misfolding diseases. PMID:22337880

Role of Bioadsorbents in Reducing Toxic Metals

PubMed Central

Jaishankar, Monisha; Biju, Vinai George; Krishnamurthy Nideghatta Beeregowda

2016-01-01

Industrialization and urbanization have led to the release of increasing amounts of heavy metals into the environment. Metal ion contamination of drinking water and waste water is a serious ongoing problem especially with high toxic metals such as lead and cadmium and less toxic metals such as copper and zinc. Several biological materials have attracted many researchers and scientists as they offer both cheap and effective removal of heavy metals from waste water. Therefore it is urgent to study and explore all possible sources of agrobased inexpensive adsorbents for their feasibility in the removal of heavy metals. The objective was to study inexpensive adsorbents like various agricultural wastes such as sugarcane bagasse, rice husk, oil palm shell, coconut shell, and coconut husk in eliminating heavy metals from waste water and their utilization possibilities based on our research and literature survey. It also shows the significance of developing and evaluating new potential biosorbents in the near future with higher adsorption capacity and greater reusable options. PMID:28090207

Role of Bioadsorbents in Reducing Toxic Metals.

PubMed

Mathew, Blessy Baby; Jaishankar, Monisha; Biju, Vinai George; Krishnamurthy Nideghatta Beeregowda

2016-01-01

Industrialization and urbanization have led to the release of increasing amounts of heavy metals into the environment. Metal ion contamination of drinking water and waste water is a serious ongoing problem especially with high toxic metals such as lead and cadmium and less toxic metals such as copper and zinc. Several biological materials have attracted many researchers and scientists as they offer both cheap and effective removal of heavy metals from waste water. Therefore it is urgent to study and explore all possible sources of agrobased inexpensive adsorbents for their feasibility in the removal of heavy metals. The objective was to study inexpensive adsorbents like various agricultural wastes such as sugarcane bagasse, rice husk, oil palm shell, coconut shell, and coconut husk in eliminating heavy metals from waste water and their utilization possibilities based on our research and literature survey. It also shows the significance of developing and evaluating new potential biosorbents in the near future with higher adsorption capacity and greater reusable options.

Performance of Raphidocelis subcapitata exposed to heavy metal mixtures.

PubMed

Expósito, Nora; Kumar, Vikas; Sierra, Jordi; Schuhmacher, Marta; Giménez Papiol, Gemma

2017-12-01

Microalgae growth inhibition assays are candidates for referent ecotoxicological assays, and are a fundamental part in the strategy to reduce the use of fish and other animal models in aquatic toxicology. In the present work, the performance of Raphidocelis subcapitata exposed to heavy metals following standardized growth inhibition assays has been assessed in three different scenarios: 1) dilutions of single heavy metals, 2) artificial mixture of heavy metals at similar levels than those found in natural rivers and, 3) natural samples containing known mixtures of contaminants (heavy metals). Chemical speciation of heavy metals has been estimated with Eh-pH diagram and Visual MINTEQ software; heavy metal and free heavy metal ion concentrations were used as input data, together with microalgae growth inhibition, for Dr. Fit software. The final goal was to assess the suitability of the ecotoxicological test based on the growth inhibition of microalgae cultures, and the mathematic models based on these results, for regulatory and decision-making purposes. The toxicity of a given heavy metal is not only determined by its chemical speciation; other chemical and biological interaction play an important role in the final toxicity. Raphidocelis subcapitata 48h-h-EC50 for tested heavy metals (especially Cu and Zn) were in agreement with previous studies, when ion metal bioavailability was assumed to be 100%. Nevertheless, the calculated growth inhibition was not in agreement with the obtained inhibition when exposed to the artificial mixture of heavy metals or the natural sample. Interactions between heavy metal ions and the compounds of the culture media and/or the natural sample determine heavy metal bioavailability, and eventually their toxicity. More research is needed for facing the challenge posed by pollutant mixtures as they are present in natural environments, and make microalgae-based assays suitable for pollution management and regulatory purposes. Copyright © 2017 Elsevier B.V. All rights reserved.

Influence of heavy metals and 4-nonylphenol on reproductive function in fish.

PubMed

Popek, Włodzimierz; Dietrich, Grzegorz; Glogowski, Jan; Demska-Zakeś, Krystyna; Drag-Kozak, Ewa; Sionkowski, Jan; Łuszczek-Trojan, Ewa; Epler, Piotr; Demianowicz, Wiesław; Sarosiek, Beata; Kowalski, Radosław; Jankun, Małgorzata; Zakeś, Zdzisław; Król, Jarosław; Czerniak, Stanisław; Szczepkowski, Mirosław

2006-01-01

Many industrial and agricultural chemicals (including heavy metals and alkylphenols) present in the environment have adverse effects on the reproductive function in fish. Three studies were conducted to assess toxicity of these chemicals towards reproduction of freshwater fish. It was shown that heavy metals added to the diets accumulate in brain tissue of carp, and this accumulation results in inhibition of the secretion of noradrenaline and stimulation of the secretion of dopamine in the hypothalamus. These processes results in a disturbance of hormonal equilibrium of the hypothalamo-pituitary system, which can unfavorably influence the efficiency of artificial spawning in fish. Quality of salmonid and sturgeon sperm was impaired after in vitro exposure to heavy metals. The degree of this toxic effect was species-specific. It was demonstrated that sperm motility parameters appeared to be good indicators of adverse effects of heavy metals fish sperm. The protection role of seminal plasma against toxic effects of heavy metals was suggested for salmonid fish. Oral application of 4-nonylphenol (NP) disrupted reproduction in pikeperch. In juvenile fish a decrease in the percentage of males and an increase of intersex fish was observed in relation to dose of NP and time of exposure to this alkylphenol. Exposure of adult males to the NP led to the reduction in fecundity, milt quality and fertility.

AAVrh.10-mediated expression of an anti-cocaine antibody mediates persistent passive immunization that suppresses cocaine-induced behavior.

PubMed

Rosenberg, Jonathan B; Hicks, Martin J; De, Bishnu P; Pagovich, Odelya; Frenk, Esther; Janda, Kim D; Wee, Sunmee; Koob, George F; Hackett, Neil R; Kaminsky, Stephen M; Worgall, Stefan; Tignor, Nicole; Mezey, Jason G; Crystal, Ronald G

2012-05-01

Cocaine addiction is a major problem affecting all societal and economic classes for which there is no effective therapy. We hypothesized an effective anti-cocaine vaccine could be developed by using an adeno-associated virus (AAV) gene transfer vector as the delivery vehicle to persistently express an anti-cocaine monoclonal antibody in vivo, which would sequester cocaine in the blood, preventing access to cognate receptors in the brain. To accomplish this, we constructed AAVrh.10antiCoc.Mab, an AAVrh.10 gene transfer vector expressing the heavy and light chains of the high affinity anti-cocaine monoclonal antibody GNC92H2. Intravenous administration of AAVrh.10antiCoc.Mab to mice mediated high, persistent serum levels of high-affinity, cocaine-specific antibodies that sequestered intravenously administered cocaine in the blood. With repeated intravenous cocaine challenge, naive mice exhibited hyperactivity, while the AAVrh.10antiCoc.Mab-vaccinated mice were completely resistant to the cocaine. These observations demonstrate a novel strategy for cocaine addiction by requiring only a single administration of an AAV vector mediating persistent, systemic anti-cocaine passive immunity.

Nanoparticle growth and surface chemistry changes in cell-conditioned culture medium.

PubMed

Kendall, Michaela; Hodges, Nikolas J; Whitwell, Harry; Tyrrell, Jess; Cangul, Hakan

2015-02-05

When biomolecules attach to engineered nanoparticle (ENP) surfaces, they confer the particles with a new biological identity. Physical format may also radically alter, changing ENP stability and agglomeration state within seconds. In order to measure which biomolecules are associated with early ENP growth, we studied ENPs in conditioned medium from A549 cell culture, using dynamic light scattering (DLS) and linear trap quadrupole electron transfer dissociation mass spectrometry. Two types of 100 nm polystyrene particles (one uncoated and one with an amine functionalized surface) were used to measure the influence of surface type. In identically prepared conditioned medium, agglomeration was visible in all samples after 1 h, but was variable, indicating inter-sample variability in secretion rates and extracellular medium conditions. In samples conditioned for 1 h or more, ENP agglomeration rates varied significantly. Agglomerate size measured by DLS was well correlated with surface sequestered peptide number for uncoated but not for amine coated polystyrene ENPs. Amine-coated ENPs grew much faster and into larger agglomerates associated with fewer sequestered peptides, but including significant sequestered lactose dehydrogenase. We conclude that interference with extracellular peptide balance and oxidoreductase activity via sequestration is worthy of further study, as increased oxidative stress via this new mechanism may be important for cell toxicity. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Na+/K+-ATPase resistance and cardenolide sequestration: basal adaptations to host plant toxins in the milkweed bugs (Hemiptera: Lygaeidae: Lygaeinae)

PubMed Central

Bramer, Christiane; Dobler, Susanne; Deckert, Jürgen; Stemmer, Michael; Petschenka, Georg

2015-01-01

Despite sequestration of toxins being a common coevolutionary response to plant defence in phytophagous insects, the macroevolution of the traits involved is largely unaddressed. Using a phylogenetic approach comprising species from four continents, we analysed the ability to sequester toxic cardenolides in the hemipteran subfamily Lygaeinae, which is widely associated with cardenolide-producing Apocynaceae. In addition, we analysed cardenolide resistance of their Na+/K+-ATPases, the molecular target of cardenolides. Our data indicate that cardenolide sequestration and cardenolide-resistant Na+/K+-ATPase are basal adaptations in the Lygaeinae. In two species that shifted to non-apocynaceous hosts, the ability to sequester was secondarily reduced, yet Na+/K+-ATPase resistance was maintained. We suggest that both traits evolved together and represent major coevolutionary adaptations responsible for the evolutionary success of lygaeine bugs. Moreover, specialization on cardenolides was not an evolutionary dead end, but enabled this insect lineage to host shift to cardenolide-producing plants from distantly related families. PMID:25808891

Phytoremediation: Using green plants to clean up contaminated soil, groundwater, and wastewater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Negri, M.C.; Hinchman, R.R.

1996-05-01

Phytoremediation, an emerging cleanup technology for contaminated soils, groundwater, and wastewater that is both low-tech and low-cost, is defined as the engineered use of green plants (including grasses, forbs, and woody species) to remove, contain, or render harmless such environmental contaminants as heavy metals, trace elements, organic compounds ({open_quotes}organics{close_quotes}), and radioactive compounds in soil or water. Current research at Argonne National Laboratory includes a successful field demonstration of a plant bioreactor for processing the salty wastewater from petroleum wells; the demonstration is currently under way at a natural gas well site in Oklahoma, in cooperation with Devon Energy Corporation. Amore » greenhouse experiment on zinc uptake in hybrid poplar (Populus sp.) was initiated in 1995. These experiments are being conducted to confirm and extend field data from Applied Natural Sciences, Inc. (our CRADA partner), indicating high levels of zinc (4,200 ppm) in leaves of hybrid poplar growing as a cleanup system at a site with zinc contamination in the root zone of some of the trees. Analyses of soil water from experimental pots that had received several doses of zinc indicated that the zinc was totally sequestered by the plants in about 4 hours during a single pass through the root system. The data also showed concentrations of sequestered metal of >38,000 ppm Zn in the dry root tissue. These levels of sequestered zinc exceed the levels found in either roots or tops of many of the known {open_quotes}hyperaccumulator{close_quotes} species. Because the roots sequester most of the contaminant taken up in most plants, a major objective of this program is to determine the feasibility of root harvesting as a method to maximize the removal of contaminants from soils. Available techniques and equipment for harvesting plant roots, including young tree roots, are being evaluated and modified as necessary for use with phytoremediation plants.« less

Toxicity assessment of heavy metal mixtures by Lemna minor L.

PubMed

Horvat, Tea; Vidaković-Cifrek, Zeljka; Orescanin, Visnja; Tkalec, Mirta; Pevalek-Kozlina, Branka

2007-10-01

The discharge of untreated electroplating wastewaters directly into the environment is a certain source of heavy metals in surface waters. Even though heavy metal discharge is regulated by environmental laws many small-scale electroplating facilities do not apply adequate protective measures. Electroplating wastewaters contain large amounts of various heavy metals (the composition depending on the facility) and the pH value often bellow 2. Such pollution diminishes the biodiversity of aquatic ecosystems and also endangers human health. The aim of our study was to observe/measure the toxic effects induced by a mixture of seven heavy metals on a bioindicator species Lemna minor L. Since artificial laboratory metal mixtures cannot entirely predict behaviour of metal mixtures nor provide us with informations relating to the specific conditions in the realistic environment we have used an actual electroplating wastewater sample discharged from a small electroplating facility. In order to obtain three more samples with the same composition of heavy metals but at different concentrations, the original electroplating wastewater sample has undergone a purification process. The purification process used was developed by Orescanin et al. [Orescanin V, Mikelić L, Lulić S, Nad K, Rubcić M, Pavlović G. Purification of electroplating wastewaters utilizing waste by-product ferrous sulphate and wood fly ash. J Environ Sci Health A 2004; 39 (9): 2437-2446.] in order to remove the heavy metals and adjust the pH value to acceptable values for discharge into the environment. Studies involving plants and multielemental waters are very rare because of the difficulty in explaining interactions of the combined toxicities. Regardless of the complexity in interpretation, Lemna bioassay can be efficiently used to assess combined effects of multimetal samples. Such realistic samples should not be avoided because they can provide us with a wide range of information which can help explain many different interactions of metals on plant growth and metabolism. In this study we have primarily evaluated classical toxicity endpoints (relative growth rate, Nfronds/Ncolonies ratio, dry to fresh weight ratio and frond area) and measured guaiacol peroxidase (GPX) activity as early indicator of oxidative stress. Also, we have measured metal accumulation in plants treated with waste ash water sample with EDXRF analysis and have used toxic unit (TU) approach to predict which metal will contribute the most to the general toxicity of the tested samples.

Arbuscular Mycorrhizal Fungi Can Benefit Heavy Metal Tolerance and Phytoremediation

ERIC Educational Resources Information Center

Forgy, David

2012-01-01

Sites contaminated by heavy metals, such as industrial waste sites, create unwelcoming environments for plant growth. Heavy metals can have a wide range of toxic effects such as replacing essential elements or disrupting enzyme function. While some heavy metals are essential to plant nutrition at low concentrations, high concentrations of any…

Pelletized ponderosa pine bark for adsorption of toxic heavy metals from water

Treesearch

Miyoung Oh; Mandla A. Tshabalala

2007-01-01

Bark flour from ponderosa pine (Pinus ponderosa) was consolidated into pellets using citric acid as cross-linking agent. The pellets were evaluated for removal of toxic heavy metals from synthetic aqueous solutions. When soaked in water, pellets did not leach tannins, and they showed high adsorption capacity for Cu(ll), Zn(ll), Cd(ll). and Ni(ll) under both equilibrium...

Heavy Metals in ToxCast: Relevance to Food Safety (SOT)

EPA Science Inventory

Human exposure to heavy metals occurs through food contamination due to industrial processes, vehicle emissions and farming methods. Specific toxicity endpoints have been associated with metal exposures, e.g. lead and neurotoxicity; however, numerous varieties of heavy metals hav...

Quantitative assessment of atmospheric emissions of toxic heavy metals from anthropogenic sources in China: historical trend, spatial variation distribution, uncertainties and control policies

NASA Astrophysics Data System (ADS)

Tian, H. Z.; Zhu, C. Y.; Gao, J. J.; Cheng, K.; Hao, J. M.; Wang, K.; Hua, S. B.; Wang, Y.; Zhou, J. R.

2015-04-01

Anthropogenic atmospheric emissions of typical toxic heavy metals have received worldwide concerns due to their adverse effects on human health and the ecosystem. By determining the best available representation of time-varying emission factors with S-shape curves, we established the multiyear comprehensive atmospheric emission inventories of 12 typical toxic heavy metals (Hg, As, Se, Pb, Cd, Cr, Ni, Sb, Mn, Co, Cu and Zn) from primary anthropogenic activities in China for the period of 1949-2012 for the first time. Further, we allocated the annual emissions of these heavy metals in 2010 at a high spatial resolution of 0.5° × 0.5° grid with ArcGIS methodology and surrogate indexes, such as regional population and gross domestic product (GDP). Our results show that the historical emissions of Hg, As, Se, Cd, Cr, Ni, Sb, Mn, Co, Cu and Zn during the period of 1949-2012, have been increased by about 22-128 times at an annual average growth rate of 5.1-8.0%, amounting to about 79 570 t in 2012. Nonferrous metal smelting, coal combustion of industrial boilers, brake and tyre wear, and ferrous metals smelting represent the dominant sources for Hg / Cd, As / Se / Pb / Cr / Ni / Mn / Co, Sb / Cu, and Zn, respectively. In terms of spatial variation, the majority of emissions were concentrated in relatively developed regions, especially for the northern, eastern and southern coastal regions. In addition, because of the flourishing nonferrous metals smelting industry, several southwestern and central-southern provinces play a prominent role in some specific toxic heavy metals emissions, like Hg in Guizhou and As in Yunnan. Finally, integrated countermeasures are proposed to minimize the final toxic heavy metals discharge on accounting of the current and future demand of energy-saving and pollution reduction in China.

Sublethal Toxicity Endpoints of Heavy Metals to the Nematode Caenorhabditis elegans

PubMed Central

Wu, Yue; Wang, Qiang; Li, Huixin

2016-01-01

Caenorhabditis elegans, a free-living nematode, is commonly used as a model organism in ecotoxicological studies. The current literatures have provided useful insight into the relative sensitivity of several endpoints, but few direct comparisons of multiple endpoints under a common set of experimental conditions. The objective of this study was to determine appropriate sublethal endpoints to develop an ecotoxicity screening and monitoring system. C. elegans was applied to explore the sublethal toxicity of four heavy metals (copper, zinc, cadmium and chromium). Two physiological endpoints (growth and reproduction), three behavioral endpoints (head thrash frequency, body bend frequency and feeding) and two enzymatic endpoints (acetylcholine esterase [AChE] and superoxide dismutase [SOD]) were selected for the assessment of heavy metal toxicity. The squared correlation coefficients (R2) between the responses observed and fitted by Logit function were higher than 0.90 and the RMSE were lower than 0.10, indicating a good significance statistically. There was no significant difference among the half effect concentration (EC50) endpoints in physiological and behavioral effects of the four heavy metals, indicating similar sensitivity of physiological and behavioral effects. AChE enzyme was more sensitive to copper, zinc, and cadmium than to other physiological and behavioral effects, and SOD enzyme was most sensitive to chromium. The EC50 of copper, zinc, and cadmium, to the AChE enzyme in the nematodes were 0.68 mg/L, 2.76 mg/L, and 0.92 mg/L respectively and the EC50 of chromium to the SOD enzyme in the nematode was 1.58 mg/L. The results of this study showed that there was a good concentration-response relationship between all four heavy metals and the sublethal toxicity effects to C. elegans. Considering these sublethal endpoints in terms of simplicity, accuracy, repeatability and costs of the experiments, feeding is the relatively ideal sublethal toxicity endpoint of heavy metals to C. elegans. PMID:26824831

Heavy metal speciation and toxicity characteristics of tannery sludge

NASA Astrophysics Data System (ADS)

Juel, Md. Ariful Islam; Chowdhury, Zia Uddin Md.; Ahmed, Tanvir

2016-07-01

Heavy metals present in tannery sludge can get mobilized in the environment in various forms and can be a cause for concern for the natural ecosystem and human health. The speciation of metals in sludge provides valuable information regarding their toxicity in the environment and determines their suitability for land application or disposal in landfills. Concentrations of seven heavy metals (Cr, Pb, Cd, Ni, Zn, As and Cu) in tannery sludge were determined to evaluate their toxicity levels. Metal contents ranged over the following intervals: As: 1.52-2.07 mg/kg; Pb: 57.5-67 mg/kg; Cr: 15339-26501 mg/kg; Cu: 261.3-579.5 mg/kg; Zn: 210.2-329.1 mg/kg and Ni: 137.5-141.3 mg/kg (dry weight basis). The concentrations of all heavy metals in the sludge samples were lower compared to EPA guidelines except chromium which was found to be several orders of magnitude higher than the guideline value. Toxicity Characteristics Leaching Procedure (TCLP) test indicated that the leaching potential of chromium was higher compared to the other heavy metals and exceeded the EPA land disposal restriction limits. To quantitatively assess the environmental burden of the chromium associated with tannery sludge, the IMPACT 2002+ methodology was adopted under the SimaPro software environment. Considering the USEPA limit for chromium as the baseline scenario, it was found that chromium in the tannery sludge had 6.41 times higher impact than the baseline in the categories of aquatic ecotoxicity, terrestrial ecotoxicity and non-carcinogens. Chromium has the highest contribution to toxicity in the category of aquatic ecotoxicity while copper is the major contributor to the category of terrestrial ecotoxicity in the tannery sludge.

Dietary strategies for the treatment of cadmium and lead toxicity.

PubMed

Zhai, Qixiao; Narbad, Arjan; Chen, Wei

2015-01-14

Cadmium (Cd) and lead (Pb) are toxic heavy metals that cause adverse health effects in humans and animals. Chelation therapy, the conventional treatment for heavy metal toxicity, is reported to have a number of safety and efficacy issues. Recent studies have shown that dietary supplements play important roles in protecting against Cd and Pb toxicity. This paper reviews the evidence for protective effects of essential metals, vitamins, edible plants, phytochemicals, probiotics and other dietary supplements against Cd and Pb toxicity and describes the proposed possible mechanisms. Based on these findings, dietary strategies are recommended for people at risk of Cd and Pb exposure. The application of these strategies is advantageous for both the prevention and alleviation of Cd and Pb toxicity, as such supplements can be added easily and affordably to the daily diet and are expected to have very few side effects compared to the chelation therapy.

Dietary Strategies for the Treatment of Cadmium and Lead Toxicity

PubMed Central

Zhai, Qixiao; Narbad, Arjan; Chen, Wei

2014-01-01

Cadmium (Cd) and lead (Pb) are toxic heavy metals that cause adverse health effects in humans and animals. Chelation therapy, the conventional treatment for heavy metal toxicity, is reported to have a number of safety and efficacy issues. Recent studies have shown that dietary supplements play important roles in protecting against Cd and Pb toxicity. This paper reviews the evidence for protective effects of essential metals, vitamins, edible plants, phytochemicals, probiotics and other dietary supplements against Cd and Pb toxicity and describes the proposed possible mechanisms. Based on these findings, dietary strategies are recommended for people at risk of Cd and Pb exposure. The application of these strategies is advantageous for both the prevention and alleviation of Cd and Pb toxicity, as such supplements can be added easily and affordably to the daily diet and are expected to have very few side effects compared to the chelation therapy. PMID:25594439

Mercury toxicity and antioxidants: Part 1: role of glutathione and alpha-lipoic acid in the treatment of mercury toxicity.

PubMed

Patrick, Lyn

2002-12-01

Mercury exposure is the second-most common cause of toxic metal poisoning. Public health concern over mercury exposure, due to contamination of fish with methylmercury and the elemental mercury content of dental amalgams, has long been a topic of political and medical debate. Although the toxicology of mercury is complex, there is evidence for antioxidant protection in the prevention of neurological and renal damage caused by mercury toxicity. Alpha-lipoic acid, a coenzyme of pyruvate and alpha-ketoglutarate dehydrogenase, has been used in Germany as an antioxidant and approved treatment for diabetic polyneuropathy for 40 years. Research has attempted to identify the role of antioxidants, glutathione and alpha-lipoic acid specifically, in both mitigation of heavy metal toxicity and direct chelation of heavy metals. This review of the literature will assess the role of glutathione and alpha-lipoic acid in the treatment of mercury toxicity.

Beneficial of Coriander Leaves (Coriandrum sativum L.) to Reduce Heavy Metals Contamination in Rod Shellfish

NASA Astrophysics Data System (ADS)

Winarti, S.; Pertiwi, C. N.; Hanani, A. Z.; Mujamil, S. I.; Putra, K. A.; Herlambang, K. C.

2018-01-01

Contamination of heavy metals in certain levels of food can disrupt human health. Heavy metals have toxic properties, cannot be overhauled or destroyed by living organisms, can accumulate in the body of organisms including humans, either directly or indirectly. Heavy metal Hg, Cd, Cr is a very toxic metals (can result in death or health problems that are not recovered in a short time), while heavy metal Co, Pb, Cu toxicity is moderate (can lead to both recoverable and non-recoverable health problems in a relatively long time). Hence the heavy metal contaminating the food must be eliminated or reduced to a safe level. One effort was use coriander leaves to reduce the contamination of heavy metals in fish/shellfish. The objective of the research was to prove the extract of coriander leaves can reduce heavy metal contamination of Pb, Hg and Cu in rod shellfish (lorjuk). The treatment of this research was long soaking in coriander leaves extract that were 0, 30, 60 and 90 minutes. The results showed that the longer time of soaking can decrease Pb level from 4.4 ± 0.424 ppb to 1.7 ± 0.5 ppb, Hg level from 4.11± 0.07 to 1.12± 0.6 ppb, and Cu level from 433.7 ± 0.1 ppb to 117 ± 0.78 ppb. Protein content not significant decrease in rod shellfish (lorjuk) after 90 minutes soaking time, that was from 28.56 ± 0.403% to 26,625 ± 0.19%.

Effects of conversion of mangroves into gei wai ponds on sediment heavy metals accumulation in tidal flat estuary, South China

NASA Astrophysics Data System (ADS)

Li, R.; Qiu, G.; Chai, M.; Li, R.

2017-12-01

Gei wai ponds act as important component in mangrove ecosystem, but the conversion of mangroves into gei wai ponds and its ecological function on heavy metal accumulation is still not clear. The study quantified the sediment heavy metal concentration and speciation in gei wai pond, Avicennia marina marsh and mudflat in Futian mangrove wetlands, South China. The results showed that gei wai pond acidified the sediment and reduced its fertility due to reduced pH, electronic conductivity (EC) and total organic carbon (TOC) compared to A. marina marsh and mudflat. The concentrations of Cd, Cu, Zn and Pb at all depth in gei wai pond sediment were also lower than other sites, indicating reduced storage function on heavy metals. Multiple analysis implied that heavy metals in all sites could be attributed to anthropogenic sources, with Cr as natural and anthropogenic sources in gei wai pond. Gei wai pond sediment had lower heavy metal pollution based on multiple evaluation methods, including potential ecological risk coefficient (Eir), potential ecological risk index (RI), geo-accumulation index (Igeo), mean PEL quotients (m-PEL-q), pollution load index (PLI), mean ERM quotients (m-ERM-q) and total toxic unit (∑TU). Heavy metal speciation analysis indicated that gei wai pond improved the conversion from the immobilized Cd and Cr to the mobilized fraction. SEM-AVS analysis indicated no adverse toxicity occurred in all sites, and the role of TOC in relieving sediment heavy metal toxicity of gei wai pond is limited.

Sources, distribution, bioavailability, toxicity, and risk assessment of heavy metal(loid)s in complementary medicines.

PubMed

Bolan, Shiv; Kunhikrishnan, Anitha; Seshadri, Balaji; Choppala, Girish; Naidu, Ravi; Bolan, Nanthi S; Ok, Yong Sik; Zhang, Ming; Li, Chun-Guang; Li, Feng; Noller, Barry; Kirkham, Mary Beth

2017-11-01

The last few decades have seen the rise of alternative medical approaches including the use of herbal supplements, natural products, and traditional medicines, which are collectively known as 'Complementary medicines'. However, there are increasing concerns on the safety and health benefits of these medicines. One of the main hazards with the use of complementary medicines is the presence of heavy metal(loid)s such as arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg). This review deals with the characteristics of complementary medicines in terms of heavy metal(loid)s sources, distribution, bioavailability, toxicity, and human risk assessment. The heavy metal(loid)s in these medicines are derived from uptake by medicinal plants, cross-contamination during processing, and therapeutic input of metal(loid)s. This paper discusses the distribution of heavy metal(loid)s in these medicines, in terms of their nature, concentration, and speciation. The importance of determining bioavailability towards human health risk assessment was emphasized by the need to estimate daily intake of heavy metal(loid)s in complementary medicines. The review ends with selected case studies of heavy metal(loid) toxicity from complementary medicines with specific reference to As, Cd, Pb, and Hg. The future research opportunities mentioned in the conclusion of review will help researchers to explore new avenues, methodologies, and approaches to the issue of heavy metal(loid)s in complementary medicines, thereby generating new regulations and proposing fresh approach towards safe use of these medicines. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pb Neurotoxicity: Neuropsychological Effects of Lead Toxicity

PubMed Central

Mason, Lisa H.; Harp, Jordan P.; Han, Dong Y.

2014-01-01

Neurotoxicity is a term used to describe neurophysiological changes caused by exposure to toxic agents. Such exposure can result in neurocognitive symptoms and/or psychiatric disturbances. Common toxic agents include heavy metals, drugs, organophosphates, bacterial, and animal neurotoxins. Among heavy metal exposures, lead exposure is one of the most common exposures that can lead to significant neuropsychological and functional decline in humans. In this review, neurotoxic lead exposure's pathophysiology, etiology, and epidemiology are explored. In addition, commonly associated neuropsychological difficulties in intelligence, memory, executive functioning, attention, processing speed, language, visuospatial skills, motor skills, and affect/mood are explored. PMID:24516855

Heavy-metal-induced reactive oxygen species: phytotoxicity and physicochemical changes in plants.

PubMed

Shahid, Muhammad; Pourrut, Bertrand; Dumat, Camille; Nadeem, Muhammad; Aslam, Muhammad; Pinelli, Eric

2014-01-01

As a result of the industrial revolution, anthropogenic activities have enhanced there distribution of many toxic heavy metals from the earth's crust to different environmental compartments. Environmental pollution by toxic heavy metals is increasing worldwide, and poses a rising threat to both the environment and to human health.Plants are exposed to heavy metals from various sources: mining and refining of ores, fertilizer and pesticide applications, battery chemicals, disposal of solid wastes(including sewage sludge), irrigation with wastewater, vehicular exhaust emissions and adjacent industrial activity.Heavy metals induce various morphological, physiological, and biochemical dysfunctions in plants, either directly or indirectly, and cause various damaging effects. The most frequently documented and earliest consequence of heavy metal toxicity in plants cells is the overproduction of ROS. Unlike redox-active metals such as iron and copper, heavy metals (e.g, Pb, Cd, Ni, AI, Mn and Zn) cannot generate ROS directly by participating in biological redox reactions such as Haber Weiss/Fenton reactions. However, these metals induce ROS generation via different indirect mechanisms, such as stimulating the activity of NADPH oxidases, displacing essential cations from specific binding sites of enzymes and inhibiting enzymatic activities from their affinity for -SH groups on the enzyme.Under normal conditions, ROS play several essential roles in regulating the expression of different genes. Reactive oxygen species control numerous processes like the cell cycle, plant growth, abiotic stress responses, systemic signalling, programmed cell death, pathogen defence and development. Enhanced generation of these species from heavy metal toxicity deteriorates the intrinsic antioxidant defense system of cells, and causes oxidative stress. Cells with oxidative stress display various chemical,biological and physiological toxic symptoms as a result of the interaction between ROS and biomolecules. Heavy-metal-induced ROS cause lipid peroxidation, membrane dismantling and damage to DNA, protein and carbohydrates. Plants have very well-organized defense systems, consisting of enzymatic and non-enzymatic antioxidation processes. The primary defense mechanism for heavy metal detoxification is the reduced absorption of these metals into plants or their sequestration in root cells.Secondary heavy metal tolerance mechanisms include activation of antioxidant enzymes and the binding of heavy metals by phytochelatins, glutathione and amino acids. These defense systems work in combination to manage the cascades of oxidative stress and to defend plant cells from the toxic effects of ROS.In this review, we summarized the biochemiCal processes involved in the over production of ROS as an aftermath to heavy metal exposure. We also described the ROS scavenging process that is associated with the antioxidant defense machinery.Despite considerable progress in understanding the biochemistry of ROS overproduction and scavenging, we still lack in-depth studies on the parameters associated with heavy metal exclusion and tolerance capacity of plants. For example, data about the role of glutathione-glutaredoxin-thioredoxin system in ROS detoxification in plant cells are scarce. Moreover, how ROS mediate glutathionylation (redox signalling)is still not completely understood. Similarly, induction of glutathione and phytochelatins under oxidative stress is very well reported, but it is still unexplained that some studied compounds are not involved in the detoxification mechanisms. Moreover,although the role of metal transporters and gene expression is well established for a few metals and plants, much more research is needed. Eventually, when results for more metals and plants are available, the mechanism of the biochemical and genetic basis of heavy metal detoxification in plants will be better understood. Moreover, by using recently developed genetic and biotechnological tools it may be possible to produce plants that have traits desirable for imparting heavy metal tolerance.

Effect of paper mill effluents on accumulation of heavy metals in coconut trees near Nanjangud, mysore district, Karnataka, India

NASA Astrophysics Data System (ADS)

Fazeli, M. Sharif; Sathyanarayan, S.; Satish, P. N.; Muthanna, Lata

1991-01-01

Physicochemical characteristics of wastewater from one of the paper mills near Nanjangud and the differential accumulation of heavy metals in parts of coconut trees growing in the area irrigated directly by the wastewaters of a paper mill were investigated. The total dissolved and suspended solids of wastewater were 1,136.9 mg/l and 2,185.4 mg/l, respectively. Biological oxygen demand (BOD) expands and COD is beyond the tolerance limit proposed by Indian standards. The concentrations of heavy metals like Cu, Pb, Zn, Ni, Co, and Cd in coconut water, root, and leaf are higher than the limits suggested by World Health Organization. Survival of coconut trees irrigated by polluted waters indicates tolerance to toxic heavy metals. Since coconut forms part of human food chain, accumulation of toxic heavy metals may lead to organic disorders.

Analytical strategies based on quantum dots for heavy metal ions detection.

PubMed

Vázquez-González, Margarita; Carrillo-Carrion, Carolina

2014-01-01

Heavy metal contamination is one of the major concerns to human health because these substances are toxic and retained by the ecological system. Therefore, in recent years, there has been a pressing need for fast and reliable methods for the analysis of heavy metal ions in environmental and biological samples. Quantum dots (QDs) have facilitated the development of sensitive sensors over the past decade, due to their unique photophysical properties, versatile surface chemistry and ligand binding ability, and the possibility of the encapsulation in different materials or attachment to different functional materials, while retaining their native luminescence property. This paper comments on different sensing strategies with QD for the most toxic heavy metal ions (i.e., cadmium, Cd2+; mercury, Hg2+; and lead, Pb2+). Finally, the challenges and outlook for the QD-based sensors for heavy metals ions are discussed.

Detoxifying PCDD/Fs and heavy metals in fly ash from medical waste incinerators with a DC double are plasma torch.

PubMed

Pan, Xinchao; Yan, Jianhua; Xie, Zhengmiao

2013-07-01

Medical waste incinerator (MWI) fly ash is regarded as a highly toxic waste because it contains high concentrations of heavy metals and dioxins, including polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Therefore fly ash from MWI must be appropriately treated before being discharged into the environment. A melting process based on a direct current thermal plasma torch has been developed to convert MWI fly ash into harmless slag. The leaching characteristics of heavy metals in fly ash and vitrified slag were investigated using the toxicity characteristic leaching procedure, while the content of PCDD/Fs in the fly ashes and slags was measured using method 1613 of the US EPA. The experimental results show that the decomposition rate of PCDD/Fs is over 99% in toxic equivalent quantity value and the leaching of heavy metals in the slag significantly decreases after the plasma melting process. The produced slag has a compact and homogeneous microstructure with density of up to 2.8 g/cm3.

Affordable Environmental Technology: Preparing for the 21st Century

DTIC Science & Technology

1992-12-20

35 HEAVY METAL REMOVAL ...................................................... ............ 38 FIRE...environmental pollutants, or that effectively concentrate heavy metals (mercury), and with these strains to produce efficient pollutant removal...93. These sediments have accumulated toxic organic and inorganic ( heavy metals ) materials for decades. In those harbors where there is little

Preclinical evaluations of norcantharidin-loaded intravenous lipid microspheres with low toxicity.

PubMed

Lin, Xia; Zhang, Bo; Zhang, Keru; Zhang, Yu; Wang, Juan; Qi, Na; Yang, Shenshen; He, Haibing; Tang, Xing

2012-12-01

The aim of this study was to perform a systematic preclinical evaluation of norcantharidin (NCTD)-loaded intravenous lipid microspheres (NLM). Pharmacokinetics, biodistribution, antitumor efficacy and drug safety assessment (including acute toxicity, subchronic toxicity, hemolysis testing, intravenous stimulation and injection anaphylaxis) of NLM were carried out in comparison with the commercial product disodium norcantharidate injection (NI). The pharmacokinetics of NLM in rats was similar to that of NI, and a non-linear correlation was observed between AUC and dose. A comparable antitumor efficacy of NLM and NI was observed in mice inoculated with A549, BEL7402 and BCAP-37 cell lines. It was worth noting that the NLM produced a lower drug concentration in heart compared with NI, and significantly reduced the cardiac and renal toxicity. The LD(50) of NLM was twice higher than that of NI. In NLM, over 80% of NCTD was loaded in the lipid phase or bound with phospholipids. Thus, NCTD was sequestered by direct contacting with body fluids and largely avoided distribution into tissues, consequently leading to significantly reduced cardiac and renal toxicity. These preclinical results suggested that NLM could be a useful potential carrier for parenteral administration of NCTD, while providing a superior safety profile.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fazeli, M.S.; Sathyanarayan, S.; Satish, P.N.

Physicochemical characteristics of wastewater from one of the paper mills near Nanjangud and the differential accumulation of heavy metals in parts of coconut trees growing in the area irrigated directly by the wastewaters of a paper mill were investigated. The total dissolved and suspended oils of wastewater were 1,136.9 mg/l and 2,185.4 mg/l, respectively. Biological oxygen demand (BOD) expands and COD is beyond the tolerance limit proposed by Indian standards. The concentrations of heavy meals like Cu, Pb, Zn, Ni, Coo, and Cd in coconut water, root, and leaf are higher than the limits suggested by World Health Organization. Survivalmore » of coconut trees irrigated by polluted waters indicates tolerance to toxic heavy metals. Since coconut forms part of human food chain, accumulation of toxic heavy metals may lead to organic disorders.« less

Heavy metals effects on forage crops yields and estimation of elements accumulation in plants as affected by soil.

PubMed

Grytsyuk, N; Arapis, G; Perepelyatnikova, L; Ivanova, T; Vynograds'ka, V

2006-02-01

Heavy metals (Cu, Cd, Pb, Zn) effect on the productivity of forage crops (clover and perennial cereal grasses) and their accumulation in plants, depending on the concentration of these elements in a soil, has been studied in micro-field experiments on three types of soil. The principle objective was to determine regularities of heavy metals migration in a soil-plant system aiming the estimation of permissible levels of heavy metals content in soils with the following elaboration of methods, which regulate the toxicants transfer to plants. Methods of field experiments, agrochemical and atomic absorption analysis were used. Results were statistically treated by Statistica 6.0, S-Plus 6. Experimental results have shown that the intensity of heavy metals accumulation in plants depends on the type of the soil, the species of plants, the physicochemical properties of heavy metals and their content in the soil. Logarithmic interdependency of heavy metals concentration in soils and their accumulation in plants is suggested. However, the strong correlation between the different heavy metals concentrations in the various soils and the yield of crops was not observed. Toxicants accumulation in crops decreased in time.

Protein sequences insight into heavy metal tolerance in Cronobacter sakazakii BAA-894 encoded by plasmid pESA3.

PubMed

Chaturvedi, Navaneet; Kajsik, Michal; Forsythe, Stephen; Pandey, Paras Nath

2015-12-01

The recently annotated genome of the bacterium Cronobacter sakazakii BAA-894 suggests that the organism has the ability to bind heavy metals. This study demonstrates heavy metal tolerance in C. sakazakii, in which proteins with the heavy metal interaction were recognized by computational and experimental study. As the result, approximately one-fourth of proteins encoded on the plasmid pESA3 are proposed to have potential interaction with heavy metals. Interaction between heavy metals and predicted proteins was further corroborated using protein crystal structures from protein data bank database and comparison of metal-binding ligands. In addition, a phylogenetic study was undertaken for the toxic heavy metals, arsenic, cadmium, lead and mercury, which generated relatedness clustering for lead, cadmium and arsenic. Laboratory studies confirmed the organism's tolerance to tellurite, copper and silver. These experimental and computational study data extend our understanding of the genes encoding for proteins of this important neonatal pathogen and provide further insights into the genotypes associated with features that can contribute to its persistence in the environment. The information will be of value for future environmental protection from heavy toxic metals.

Assessment of heavy metal impact on sediment quality of the Xiaoqinghe estuary in the coastal Laizhou Bay, Bohai Sea: inconsistency between two commonly used criteria.

PubMed

Zhuang, Wen; Gao, Xuelu

2014-06-15

Surface sediments in the Xiaoqinghe estuary, southwestern coastal Laizhou Bay, were examined to assess the bio-toxic risk of heavy metals (Cd, Cu, Ni, Pb and Zn) with the effects range-low and effects range-median guidelines (ERL-ERMs) and the concentration ratio of simultaneously extractable metals to acid volatile sulfides ([SEM]/[AVS]). Based on the ERL-ERM guidelines, bio-toxic effect caused by Cu, Ni, Pb and Zn could be expected in the riverine surface sediments of the Xiaoqinghe estuary; and the surface sediments in the marine area were in good quality and only Ni might cause bio-toxic effect occasionally. The AVS-SEM guidelines revealed that no bio-toxic effect could be caused by any of the studied metals in both the riverine and marine sediments, since there were excess sulfides in surface sediments which could form water-insoluble substances with free metal ions and reduce the bioavailability of heavy metals. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Pyoverdin Siderophore Produced By Pseudomonas aeruginosa CHL-004 Binds Lead And Other Heavy Metals

EPA Science Inventory

Heavy metal pollution in soils, sediments and wastewater poses a significant environmental and public health threat due to toxicity and the potential for bioaccumulation in both plant and animal tissues. Remediation of heavy metals in soils and sediments using solely physical or...

A Pyoverdin Siderophore Produced By Pseudomonas aeruginosa CHL-004 Binds Lead And Other Heavy Metals - (Poster)

EPA Science Inventory

Heavy metal pollution in soils, sediments and wastewater poses a significant environmental and public health threat due to toxicity and the potential for bioaccumulation in both plant and animal tissues. Remediation of heavy metals in soils and sediments using solely physical or...

Sulfur Mediated Alleviation of Mn Toxicity in Polish Wheat Relates to Regulating Mn Allocation and Improving Antioxidant System

PubMed Central

Sheng, Huajin; Zeng, Jian; Liu, Yang; Wang, Xiaolu; Wang, Yi; Kang, Houyang; Fan, Xing; Sha, Lina; Zhang, Haiqin; Zhou, Yonghong

2016-01-01

Sulfur (S) is an essential macronutrient that has been proved to play an important role in regulating plant responses to various biotic and abiotic stresses. The present study was designed to investigate the effect of S status on polish wheat plant response to Mn toxicity. Results showed that Mn stress inhibited plant growth, disturbed photosynthesis and induced oxidative stress. In response to Mn stress, polish wheat plant activated several detoxification mechanisms to counteract Mn toxicity, including enhanced antioxidant defense system, increased Mn distribution in the cell wall and up-regulated genes involved in S assimilation. Moderate S application was found to alleviate Mn toxicity mainly by sequestering excess Mn into vacuoles, inhibiting Mn translocation from roots to shoots, stimulating activities of antioxidant enzymes and enhancing GSH production via up-regulating genes involved in S metabolism. However, application of high level S to Mn-stressed plants did not significantly alleviated Mn toxicity likely due to osmotic stress. In conclusion, moderate S application is beneficial to polish wheat plant against Mn toxicity, S exerts its effects via stimulating the antioxidant defense system and regulating the translocation and subcellular distribution of Mn, in which processes GSH plays an indispensable role. PMID:27695467

Toxic effects of environmental rare earth elements on delayed outward potassium channels and their mechanisms from a microscopic perspective.

PubMed

Wang, Lihong; He, Jingfang; Xia, Ao; Cheng, Mengzhu; Yang, Qing; Du, Chunlei; Wei, Haiyan; Huang, Xiaohua; Zhou, Qing

2017-08-01

The wide applications cause a large amount of rare earth elements (REEs) to be released into the environment, and ultimately into the human body through food chain. Toxic effects of REEs on humans have been extensively studied, but their toxic effects and binding targets in cells are not understood. Delayed outward potassium channels (K + channels) are good targets for exogenous substances or clinical drugs. To evaluate cellular toxicities of REEs and clarify toxic mechanisms, the toxicities of REEs on the K + channel and their structural basis were investigated. The results showed that delayed outward potassium channels on the plasma membrane are the targets of REEs acting on living organisms, and the changes in the thermodynamic and kinetic characteristics of the K + channel are the reasons of diseases induced by REEs. Two types of REEs, a light REE La 3+ and a heavy REE Tb 3+ , displayed different intensity of toxicities on the K + channel, in which the toxicity of Tb 3+ was stronger than that of La 3+ . More interestingly, in comparison with that of heavy metal Cd 2+ , the cytotoxicities of the light and heavy REEs showed discriminative differences, and the cytotoxicity of Tb 3+ was higher than that of Cd 2+ , while the cytotoxicity of La 3+ was lower than that of Cd 2+ . These different cytotoxicities of La 3+ , Tb 3+ and Cd 2+ on human resulted from the varying binding abilities of the metals to this channel protein. Copyright © 2017 Elsevier Ltd. All rights reserved.

Radio-toxicity of spent fuel of the advanced heavy water reactor.

PubMed

Anand, S; Singh, K D S; Sharma, V K

2010-01-01

The Advanced Heavy Water Reactor (AHWR) is a new power reactor concept being developed at Bhabha Atomic Research Centre, Mumbai. The reactor retains many desirable features of the existing Pressurised Heavy Water Reactor (PHWR), while incorporating new, advanced safety features. The reactor aims to utilise the vast thorium resources available in India. The reactor core will use plutonium as the make-up fuel, while breeding (233)U in situ. On account of this unique combination of fuel materials, the operational characteristics of the fuel as determined by its radioactivity, decay heat and radio-toxicity are being viewed with great interest. Radio-toxicity of the spent fuel is a measure of potential radiological hazard to the members of the public and also important from the ecological point of view. The radio-toxicity of the AHWR fuel is extremely high to start with, being approximately 10(4) times that of the fresh natural U fuel used in a PHWR, and continues to remain relatively high during operation and subsequent cooling. A unique feature of this fuel is the peak observed in its radio-toxicity at approximately 10(5) y of decay cooling. The delayed increase in fuel toxicity has been traced primarily to a build-up of (229)Th, (230)Th and (226)Ra. This phenomenon has been observed earlier for thorium-based fuels and is confirmed for the AHWR fuel. This paper presents radio-toxicity data for AHWR spent fuel up to a period of 10(6) y and the results are compared with the radio-toxicity of PHWR.

Metal accumulation and differentially expressed proteins in gill of oyster (Crassostrea hongkongensis) exposed to long-term heavy metal-contaminated estuary.

PubMed

Luo, Lianzhong; Ke, Caihuan; Guo, Xiaoyu; Shi, Bo; Huang, Miaoqin

2014-06-01

Bio-accumulation and bio-transmission of toxic metals and the toxicological responses of organisms exposed to toxic metals have been focused, due to heavy metal contaminations have critically threatened the ecosystem and food security. However, still few investigations focused on the responses of certain organisms exposed to the long term and severe heavy metal contamination in specific environments. In present investigation, the Hong Kong oyster, Crassostrea hongkongensis were obtained from 3 sites which were contaminated by different concentrations of heavy metals (such as zinc, copper, manganese and lead etc.), respectively. Heavy metal concentrations in the sea water samples collected from the 3 sites and the dissected tissues of the oysters with blue visceral mass were determinated to estimate the metal contamination levels in environments and the bio-accumulation ratios of the heavy metals in the different tissues of oysters. Moreover, Proteomic methods were employed to analyze the differentially expressed proteins in the gills of oysters exposed to long-term heavy metal contaminations. Results indicated that the Jiulong River estuary has been severely contaminated by Cu, Zn and slightly with Cr, Ni, Mn, etc, moreover, Zn and Cu were the major metals accumulated by oysters to phenomenally high concentrations (more than 3.0% of Zn and about 2.0% of Cu against what the dry weight of tissues were accumulated), and Cr, Ni, Mn, etc were also significantly accumulated. The differentially expressed proteins in the gills of oysters exposed to heavy metals participate in several cell processes, such as metal binding, transporting and saving, oxidative-reduction balance maintaining, stress response, signal transduction, etc. Significantly up-regulated expression (about 10 folds) of an important metal binding protein, metallothionein (MT) and granular cells was observed in the gills of oysters exposed to long-term and severely heavy-metal-contaminated estuary, it suggested that binding toxic metals with metallothionein-like proteins (MTLP) and storing toxic metals in metal-rich granules (MRG) with insoluble forms were the important strategies of oyster to detoxify the toxic metals and adapt to the high level of metal-contaminated environment. Most of the stress and immunity responsive proteins, such as heat shock proteins (HSP), extracellular superoxide dismutase (ECSOD) and cavortin, and the cellular redox reaction relative proteins such as 20G-Fe (II) oxygenase family oxidoreductase, aldehyde dehydrogenase and retinal dehydrogenase 2, were detected significantly down-regulated in the gills of oysters exposed to long term heavy metal contaminated environments, it indicated that long term exposure different from emergent exposure to heavy metal contamination may significantly suppress the stress and immunity response system of oysters. Moreover, Formin homology 2 domain containing protein (FH2). The only protein domain to directly nucleate actin monomers into unbranched filament polymers, by which will subsequently control gene expression and chromatin remodelling complexes, was also detected greatly up-regulated in the gills of oysters exposed to long-term heavy metal contaminations. It indicated that nuclear activity regulation may also be important for oyster to adapt to the long-term heavy-metal-contaminated environment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Quantifying biomineralization of zinc in the Rio Naracauli (Sardinia, Italy), using a tracer injection and synoptic sampling

USGS Publications Warehouse

De Giudici, Giovanni; Wanty, Richard B.; Podda, F.; Kimball, Briant A.; Verplanck, Philip L.; Lattanzi, P.; Cidu, R.; Medas, D.

2014-01-01

Streams draining mined areas throughout the world commonly have high concentrations of Zn. Because Zn is not easily removed from stream water and because it can be toxic to aquatic organisms, its presence is a persistent problem. The discovery of biomineralization of Zn-bearing solids in the mine drainage of Rio Naracauli, in Sardinia, Italy, provides insights into strategies for removing Zn and improving water quality in streams affected by mine drainage. Until now, the transport and attenuation of Zn has not been quantified in this stream setting. A continuous tracer injection experiment was conducted to quantify the biomineralization process and to identify the loading of constituents that causes a change from precipitation of hydrozincite [Zn5(CO3)2(OH)6] in the upstream reach to precipitation of a Zn-silicate phase downstream. Based on the mass-load calculations derived from the tracer experiment, about 1.2 kg/day of Zn is sequestered in hydrozincite. This biomineralization represents nearly 90% removal of Zn. Other elements such as Pb and Cd also are sequestered, either in the hydrozincite, or in a separate phase that forms simultaneously. In the lower 600 m of the stream, where the Zn-silicate forms, as much as 0.7 kg/day Zn are sequestered in this solid, but additions of Zn to the stream from groundwater discharge lead to an overall increase in load in that portion of the Rio Naracauli.

Development of a generalist predator, Podisus maculiventris, on glucosinolate sequestering and nonsequestering prey

NASA Astrophysics Data System (ADS)

van Geem, Moniek; Harvey, Jeffrey A.; Gols, Rieta

2014-09-01

Insect herbivores exhibit various strategies to counter the toxic effects of plant chemical defenses. These strategies include the detoxification, excretion, and sequestration of plant secondary metabolites. The latter strategy is often considered to provide an additional benefit in that it provides herbivores with protection against natural enemies such as predators. Profiles of sequestered chemicals are influenced by the food plants from which these chemicals are derived. We compared the effects of sequestration and nonsequestration of plant secondary metabolites in two specialist herbivores on the development of a generalist predator, Podisus maculiventris. Profiles of glucosinolates, secondary metabolites characteristic for the Brassicaceae, are known to differ considerably both inter- and intraspecifically. Throughout their immature (=nymphal) development, the predator was fed on larval stages of either sequestering (turnip sawfly, Athalia rosae) or nonsequestering (small cabbage white butterfly, Pieris rapae) prey that in turn had been feeding on plants originating from three wild cabbage ( Brassica oleracea) populations that have previously been shown to differ in their glucosinolate profiles. We compared survival, development time, and adult body mass as parameters for bug performance. Our results show that sequestration of glucosinolates by A. rosae only marginally affected the development of P. maculiventris. The effects of plant population on predator performance were variable. We suggest that sequestration of glucosinolates by A. rosae functions not only as a defensive mechanism against some predators, but may also be an alternative way of harmlessly dealing with plant allelochemicals.

Assessment of the quality of sewage effluents from dry weather flow channel, Calcutta.

PubMed

Adhikari, S; Gupta, S K

2002-10-01

The quality of sewage effluent of Dry weather Flow channel, Calcutta in respect of salinity, sodicity, chloride, sulphate and bicarbonate toxicity and heavy metal hazards was assessed in order to utilize it for irrigation. Although raw sewage in the winter season was toxic in respect of chlorides, sulphates, bicarbonate, BOD, COD; its dilution in the monsoon decreased the toxicity hazards considerably, making it worth using for irrigation. The sewage effluents were rich in N and K, but poor in P status with marginal concentrations of micronutrients (Fe, Cu, Zn & Mn). Heavy metal contents of the soil treated with effluents were also studied.

Assessment of the quality of sewage effluents from dry weather flow channel, Calcutta.

PubMed

Adhikari, S; Gupta, S K

2002-07-01

The quality of sewage effluent of Dry Weather Flow Channel, Calcutta in respect of salinity, sodicity, chlorides, sulphate and bicarbonate toxicity and heavy metal hazards was assessed in order to utilize it for irrigation. Although raw sewage in the winter season was toxic in respect of chlorides, sulphates, bicarbonate, BOD, COD; its dilution in the monsoon decreased the toxicity hazards considerably, making it worth using for irrigation. The sewage effluents were rich in N and K, but poor in P status with marginal concentrations of micronutrients (Fe, Cu, Zn & Mn). Heavy metal contents of the soil treated with effluents were also studied.

[Acute toxicity analysis performance of CellSense biosensor with E. coli].

PubMed

Wang, Xue-Jiang; Wang, Hong; Zhao, Jian-Fu; Xia, Si-Qing; Zhao, Hong-Ning

2009-04-15

E. coli microbial electrodes for CellSense biosensor were prepared by polycarbonate membrane immobilization process, and their performance for heavy metals and toxic organic compounds acute toxicity determination were studied. The results showed that when E. coli was in logarithmic and stationary phase, the CellSense biosensor with E. coli showed good performance in heavy metal ions and organic pollutants acute toxicity analysis, when E. coli was in its decline phase, the stability and sensitivity of the CellSense biosensor was poor. The EC50 values of Hg2+, Cu2+, Zn2+, o-chlorophenol (2-CP) and p-nitrophenol (4-NP) detected by CellSense biosensor with E. coli were 0.6, 3.1, 5.8, 180 and 94 microg/mL, respectively. The immobilized E. coli electrodes could still suit for acute toxicity assessment after 2 months storage at 4 degrees C.

Hormesis enables cells to handle accumulating toxic metabolites during increased energy flux.

PubMed

Zemva, Johanna; Fink, Christoph Andreas; Fleming, Thomas Henry; Schmidt, Leonard; Loft, Anne; Herzig, Stephan; Knieß, Robert André; Mayer, Matthias; Bukau, Bernd; Nawroth, Peter Paul; Tyedmers, Jens

2017-10-01

Energy production is inevitably linked to the generation of toxic metabolites, such as reactive oxygen and carbonyl species, known as major contributors to ageing and degenerative diseases. It remains unclear how cells can adapt to elevated energy flux accompanied by accumulating harmful by-products without taking any damage. Therefore, effects of a sudden rise in glucose concentrations were studied in yeast cells. This revealed a feedback mechanism initiated by the reactive dicarbonyl methylglyoxal, which is formed non-enzymatically during glycolysis. Low levels of methylglyoxal activate a multi-layered defence response against toxic metabolites composed of prevention, detoxification and damage remission. The latter is mediated by the protein quality control system and requires inducible Hsp70 and Btn2, the aggregase that sequesters misfolded proteins. This glycohormetic mechanism enables cells to pre-adapt to rising energy flux and directly links metabolic to proteotoxic stress. Further data suggest the existence of a similar response in endothelial cells. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Laser ablation ICP-MS profiling and semiquantitative determination of trace element concentrations in desert tortoise shells: documenting the uptake of elemental toxicants.

PubMed

Seltzer, Michaeld; Berry, Kristinh

2005-03-01

The outer keratin layer (scute) of desert tortoise shells consists of incrementally grown laminae in which various bioaccumulated trace elements are sequestered during scute deposition. Laser ablation ICP-MS examination of laminae in scutes of dead tortoises revealed patterns of trace elemental distribution from which the chronology of elemental uptake can be inferred. These patterns may be of pathologic significance in the case of elemental toxicants such as arsenic, which has been linked to both shell and respiratory diseases. Laser ablation transects, performed along the lateral surfaces of sectioned scutes, offered the most successful means of avoiding exogenous contamination that was present on the scute exterior. Semiquantitative determination of elemental concentrations was achieved using sulfur, a keratin matrix element, as an internal standard. The results presented here highlight the potential of laser ablation ICP-MS as a diagnostic tool for investigating toxic element uptake as it pertains to tortoise morbidity and mortality.

Laser ablation ICP-MS profiling and semiquantitative determination of trace element concentrations in desert tortoise shells: Documenting the uptake of elemental toxicants

USGS Publications Warehouse

Seltzer, M.D.; Berry, K.H.

2005-01-01

The outer keratin layer (scute) of desert tortoise shells consists of incrementally grown laminae in which various bioaccumulated trace elements are sequestered during scute deposition. Laser ablation ICP-MS examination of laminae in scutes of dead tortoises revealed patterns of trace elemental distribution from which the chronology of elemental uptake can be inferred. These patterns may be of pathologic significance in the case of elemental toxicants such as arsenic, which has been linked to both shell and respiratory diseases. Laser ablation transects, performed along the lateral surfaces of sectioned scutes, offered the most successful means of avoiding exogenous contamination that was present on the scute exterior. Semiquantitative determination of elemental concentrations was achieved using sulfur, a keratin matrix element, as an internal standard. The results presented here highlight the potential of laser ablation ICP-MS as a diagnostic tool for investigating toxic element uptake as it pertains to tortoise morbidity and mortality.

Toxic Substances in the Environment.

ERIC Educational Resources Information Center

Clearing: Nature and Learning in the Pacific Northwest, 1984

1984-01-01

Discusses the nature of toxic substances, examining pesticides and herbicides, heavy metals, industrial chemicals, and household substances. Includes a list of major toxic substances (indicating what they are, where they are found, and health concerns) and a student activity on how pesticides enter the food chain. (JN)

Insights into aquatic toxicities of the antibiotics oxytetracycline and ciprofloxacin in the presence of metal: complexation versus mixture.

PubMed

Zhang, Yu; Cai, Xiyun; Lang, Xianming; Qiao, Xianliang; Li, Xuehua; Chen, Jingwen

2012-07-01

Co-contamination of ligand-like antibiotics (e.g., tetracyclines and quinolones) and heavy metals prevails in the environment, and thus the complexation between them is involved in environmental risks of antibiotics. To understand toxicological significance of the complex, effects of metal coordination on antibiotics' toxicity were investigated. The complexation of two antibiotics, oxytetracycline and ciprofloxacin, with three heavy metals, copper, zinc, and cadmium, was verified by spectroscopic techniques. The antibiotics bound metals via multiple coordination sites and rendered a mixture of various complexation speciations. Toxicity analysis indicated that metal coordination did modify the toxicity of the antibiotics and that antibiotic, metal, and their complex acted primarily as concentration addition. Comparison of EC(50) values revealed that the complex commonly was highest toxic and predominately correlated in toxicity to the mixture. Finally, environmental scenario analysis demonstrated that ignoring complexation would improperly classify environmental risks of the antibiotics. Copyright © 2012 Elsevier Ltd. All rights reserved.

Metal transformation as a strategy for bacterial detoxification of heavy metals.

PubMed

Essa, Ashraf M M; Al Abboud, Mohamed A; Khatib, Sayeed I

2018-01-01

Microorganisms can modify the chemical and physical characters of metals leading to an alteration in their speciation, mobility, and toxicity. Aqueous heavy metals solutions (Hg, Cd, Pb, Ag, Cu, and Zn) were treated with the volatile metabolic products (VMPs) of Escherichia coli Z3 for 24 h using aerobic bioreactor. The effect of the metals treated with VMPs in comparison to the untreated metals on the growth of E. coli S1 and Staphylococcus aureus S2 (local isolates) was examined. Moreover, the toxic properties of the treated and untreated metals were monitored using minimum inhibitory concentration assay. A marked reduction of the treated metals toxicity was recorded in comparison to the untreated metals. Scanning electron microscopy and energy dispersive X-ray analysis revealed the formation of metal particles in the treated metal solutions. In addition to heavy metals at variable ratios, these particles consisted of carbon, oxygen, sulfur, nitrogen elements. The inhibition of metal toxicity was attributed to the existence of ammonia, hydrogen sulfide, and carbon dioxide in the VMPs of E. coli Z3 culture that might responsible for the transformation of soluble metal ions into metal complexes. This study clarified the capability of E. coli Z3 for indirect detoxification of heavy metals via the immobilization of metal ions into biologically unavailable species. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The effects of heavy metals and their interactions with polycyclic aromatic hydrocarbons on the oxidative stress among coke-oven workers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Tian; Feng, Wei; Kuang, Dan

Heavy metals and polycyclic aromatic hydrocarbons (PAHs) are predominate toxic constituents of particulate air pollution that may be related to the increased risk of cardiopulmonary events. We aim to investigate the effects of the toxic heavy metals (arsenic, As; cadmium, Cd; chromium, Cr; nickel, Ni; and lead, Pb), and their interactions with PAHs on oxidative stress among coke-oven workers. A total of 1333 male workers were recruited in this study. We determined their urinary levels of As, Cd, Cr, Ni, Pb, twelve PAH metabolites, 8-hydroxydeoxyguanosine (8-OHdG), and 8-iso-prostaglandin-F2α (8-iso-PGF2α). Multivariate linear regression models were used to analyze the effects ofmore » these metals and their interactions with PAHs on 8-OHdG and 8-iso-PGF2α levels. It was found that only urinary As and Ni showed marginal or significant positive linear dose-dependent effects on 8-OHdG in this study population, especially among smokers (β=0.103, P=0.073 and β=0.110, P=0.002, respectively). After stratifying all participants by the quartiles of ΣOH-PAH, all five metals showed linear association with 8-OHdG in the highest quartile subgroup (Q4) of ΣOH-PAHs. However, these five urinary metals showed significantly consistent linear associations with 8-iso-PGF2α in all subjects and each stratum. Urinary ΣOH-PAHs can significant modify the effects of heavy metals on oxidative stress, while co-exposure to both high levels of ΣOH-PAHs and heavy metals render the workers with highest 8-OHdG and 8-iso-PGF2α (all P{sub interaction}≤0.005). This study showed evidence on the interaction effects of heavy metals and PAHs on increasing the oxidative stress, and these results warrant further investigation in more longitudinal studies. - Highlights: • Heavy metals and PAHs are predominate toxic constituents of particulate matters. • Urinary As and Ni showed linear dose-dependent effects on 8-OHdG and 8-iso-PGF2α. • PAHs significant interact with toxic metal in increasing 8-OHdG and 8-iso-PGF2α. • Co-exposure to high PAHs and toxic metals contribute to highest oxidative stress.« less

Sensitivity of midge larvae of Chironomus tentans Fabricius (Diptera Chironomidae) to heavy metals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khangarot, B.S.; Ray, P.K.

1989-03-01

The discharge of heavy metals into the natural waters has numerous obvious impacts on physical, chemical and biological parameters of aquatic ecosystem. Bioassay tests are important steps in establishing appropriate water quality criteria and standards for diverse use of ponds, lakes, streams and river waters. Therefore, the acute toxicities of various heavy metals to water flea Daphnia magna, and snail Lymnaea acuminata, and toad tadpoles Bufo mentanostictus have been reported from the authors' laboratory. Chironomid larvae might be particularly useful as indicators of water quality because they are widely distributed in freshwater systems and often from diverse communities within particularmore » habitat. The aim of this study was to determine the acute toxicity of ten heavy metals to the midge larvae Chironomus tentans Fabricius, which forms an important link in aquatic food chain(s).« less

Bioremediation of Toxic Heavy Metals: A Patent Review.

PubMed

Verma, Neelam; Sharma, Rajni

2017-01-01

The global industrialization is fulfilling the demands of modern population at the cost of environmental exposure to various contaminants including heavy metals. These heavy metals affect water and soil quality. Moreover, these enter into the food chain and exhibit their lethal effects on the human health even when present at slightly higher concentration than required for normal metabolism. To the worst of their part, the heavy metals may become carcinogenic. Henceforth, the efficient removal of heavy metals is the demand of sustainable development. Remedy: Bioremediation is the 'green' imperative technique for the heavy metal removal without creating secondary metabolites in the ecosystem. The metabolic potential of several bacterial, algal, fungal as well as plant species has the efficiency to exterminate the heavy metals from the contaminated sites. Different strategies like bioaccumulation, biosorption, biotransformation, rhizofilteration, bioextraction and volatilization are employed for removal of heavy metals by the biological species. Bioremediation approach is presenting a splendid alternate for conventional expensive and inefficient methods for the heavy metal removal. The patents granted on the bioremediation of toxic heavy metals are summarized in the present manuscript which supported the applicability of bioremediation technique at commercial scale. However, the implementation of the present information and advanced research are mandatory to further explore the concealed potential of biological species to resume the originality of the environment. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

AAVrh.10-Mediated Expression of an Anti-Cocaine Antibody Mediates Persistent Passive Immunization That Suppresses Cocaine-Induced Behavior

PubMed Central

Rosenberg, Jonathan B.; Hicks, Martin J.; De, Bishnu P.; Pagovich, Odelya; Frenk, Esther; Janda, Kim D.; Wee, Sunmee; Koob, George F.; Hackett, Neil R.; Kaminsky, Stephen M.; Worgall, Stefan; Tignor, Nicole; Mezey, Jason G.

2012-01-01

Abstract Cocaine addiction is a major problem affecting all societal and economic classes for which there is no effective therapy. We hypothesized an effective anti-cocaine vaccine could be developed by using an adeno-associated virus (AAV) gene transfer vector as the delivery vehicle to persistently express an anti-cocaine monoclonal antibody in vivo, which would sequester cocaine in the blood, preventing access to cognate receptors in the brain. To accomplish this, we constructed AAVrh.10antiCoc.Mab, an AAVrh.10 gene transfer vector expressing the heavy and light chains of the high affinity anti-cocaine monoclonal antibody GNC92H2. Intravenous administration of AAVrh.10antiCoc.Mab to mice mediated high, persistent serum levels of high-affinity, cocaine-specific antibodies that sequestered intravenously administered cocaine in the blood. With repeated intravenous cocaine challenge, naive mice exhibited hyperactivity, while the AAVrh.10antiCoc.Mab-vaccinated mice were completely resistant to the cocaine. These observations demonstrate a novel strategy for cocaine addiction by requiring only a single administration of an AAV vector mediating persistent, systemic anti-cocaine passive immunity. PMID:22486244

Randomized Open-Label Pilot Study of the Influence of Probiotics and the Gut Microbiome on Toxic Metal Levels in Tanzanian Pregnant Women and School Children

PubMed Central

Bisanz, Jordan E.; Enos, Megan K.; Mwanga, Joseph R.; Changalucha, John; Burton, Jeremy P.; Gloor, Gregory B.

2014-01-01

ABSTRACT Exposure to environmental toxins is a 21st century global health problem that is often the result of dietary intake. Although efforts are made to reduce dietary toxin levels, they are often unsuccessful, warranting research into novel methods to reduce host exposure. Food-grade microbes that can be delivered to the gastrointestinal tract and that are capable of sequestering toxins present a safe and cost-effective intervention. We sought to investigate the potential for probiotic-supplemented yogurt to lower heavy metal levels in at-risk populations of pregnant women and in children in Mwanza, Tanzania, and to examine the microbiome in relation to toxin levels. Two populations suspected to have high toxic metal exposures were studied. A group of 44 school-aged children was followed over 25 days, and 60 pregnant women were followed over their last two trimesters until birth. A yogurt containing 1010 CFU Lactobacillus rhamnosus GR-1 per 250 g was administered, while control groups received either whole milk or no intervention. Changes in blood metal levels were assessed, and the gut microbiomes of the children were profiled by analyzing 16S rRNA sequencing via the Ion Torrent platform. The children and pregnant women in the study were found to have elevated blood levels of lead and mercury compared to age- and sex-matched Canadians. Consumption of probiotic yogurt had a protective effect against further increases in mercury (3.2 nmol/liter; P = 0.035) and arsenic (2.3 nmol/liter; P = 0.011) blood levels in the pregnant women, but this trend was not statistically significant in the children. Elevated blood lead was associated with increases in Succinivibrionaceae and Gammaproteobacteria relative abundance levels in stool. PMID:25293764

Sequential effects of cadmium on genotoxicity and lipoperoxidation in Vicia faba roots.

PubMed

Souguir, D; Ferjani, E; Ledoigt, G; Goupil, Pascale

2011-03-01

Kinetics of stress responses to Cd exposure (50, 100 and 200 μM) expanding from 12 to 48 h were studied in roots of hydroponically cultivated-Vicia faba seedlings. The heavy metal induced toxicity symptoms and growth arrest of Vicia roots gradually to the Cd concentration and duration of the treatment. The intracellular oxidative stress was evaluated with the H(2)O(2) production. The H(2)O(2) content increased gradually with the sequestered Cd and root growth inhibition. Lipid peroxidation-evidenced by malondialdehyde (MDA) content and Evans blue uptake-and genotoxicity-evidenced by mitotic index (MI) and micronuclei (MCN) values-were concomitantly investigated in root tips. By 12 h, root meristematic cells lost 15% of their mitotic activity under 50 or 100 μM Cd treatment and 50% under 200 μM Cd treatment and led cells with MCN, while the MDA content and Evans blue absorption were not affected. The loss of membrane integrity occurred subsequently by 24 h. The increase in MDA content in root cells treated with 50, 100 and 200 μM Cd was significantly higher than the control. By 48 h, the MDA content increased 134, 178 or 208% in root cells treated with 50, 100 and 200 μM Cd, respectively. The Evans blue absorption was also affected by 24 h in roots when treated with 200 μM Cd and gradually increase by 48 h with the Cd concentration of the treatment. The decrease of mitotic activity triggered by 12 h was even higher by 24 h and the MI reduced to 44, 56 or 80% compared to the control in the three different Cd concentrations tested. The different kinetics of early in vivo physiological and cytogenetic responses to Cd might be relevant to the characterization of its toxicity mechanisms in disrupting primarily the mitosis process.

Biosorption of multi-heavy metals by coral associated phosphate solubilising bacteria Cronobacter muytjensii KSCAS2.

PubMed

Saranya, Kailasam; Sundaramanickam, Arumugam; Shekhar, Sudhanshu; Meena, Moorthy; Sathishkumar, Rengasamy Subramaniyan; Balasubramanian, Thangavel

2018-06-02

This paper examines the potential detoxification efficiency of heavy metals by phosphate solubilising bacteria (PSB) that were isolated from coral, sea grass and mangrove environment. Initially, four potential bacterial isolates were selected based on their phosphate solubilisation index from 42 strains and were used for the metal tolerance test. Among the four isolates, KSCAS2 exhibited maximum tolerance to heavy metals and the phenotype indicated the production of extra polymeric substances. In a multi-heavy metal experimental setup at two concentrations (100 and 200 mg L -l ), it has been demonstrated that the bacteria have extracellularly sequestered metal ions in amorphous deposits and this has been confirmed by scanning electron microscopy. In experiments with a 100 mg L -1 initial metal concentration, the percentages of metal removal by bacteria were 55.23% of Cd, 72.45% of Cr, 76.51% of Cu and 61.51% of Zn, respectively. In subsequent experiments, when the metal concentration was increased up to 200 mg L -l , the metal removal capacity decreased as follows: 44.62%, 63.1%, 67% and 52.80% for Cd, Cr, Cu and Zn, respectively. In addition, the biosorption of heavy metals was confirmed by the Fourier transform infrared Spectroscopy (FT-IR) and scanning electron microscopy (SEM) analysis. The heavy metal concentrations in a broth culture were analysed by inductively coupled plasma-optical emission spectroscopy (ICP-OES). The study suggests that PSB Cronobacter muytjensii KSCAS2 can efficiently remove the heavy metals and these bacteria could be used for the metal removal from the agricultural soils. Copyright © 2018. Published by Elsevier Ltd.

Toxin-Antitoxin Systems as Multilevel Interaction Systems

PubMed Central

Goeders, Nathalie; Van Melderen, Laurence

2014-01-01

Toxin-antitoxin (TA) systems are small genetic modules usually composed of a toxin and an antitoxin counteracting the activity of the toxic protein. These systems are widely spread in bacterial and archaeal genomes. TA systems have been assigned many functions, ranging from persistence to DNA stabilization or protection against mobile genetic elements. They are classified in five types, depending on the nature and mode of action of the antitoxin. In type I and III, antitoxins are RNAs that either inhibit the synthesis of the toxin or sequester it. In type II, IV and V, antitoxins are proteins that either sequester, counterbalance toxin activity or inhibit toxin synthesis. In addition to these interactions between the antitoxin and toxin components (RNA-RNA, protein-protein, RNA-protein), TA systems interact with a variety of cellular factors, e.g., toxins target essential cellular components, antitoxins are degraded by RNAses or ATP-dependent proteases. Hence, TA systems have the capacity to interact with each other at different levels. In this review, we will discuss the different interactions in which TA systems are involved and their implications in TA system functions and evolution. PMID:24434905

A New Strategy for Heavy Metal Polluted Environments: A Review of Microbial Biosorbents

PubMed Central

Ayangbenro, Ayansina Segun; Babalola, Olubukola Oluranti

2017-01-01

Persistent heavy metal pollution poses a major threat to all life forms in the environment due to its toxic effects. These metals are very reactive at low concentrations and can accumulate in the food web, causing severe public health concerns. Remediation using conventional physical and chemical methods is uneconomical and generates large volumes of chemical waste. Bioremediation of hazardous metals has received considerable and growing interest over the years. The use of microbial biosorbents is eco-friendly and cost effective; hence, it is an efficient alternative for the remediation of heavy metal contaminated environments. Microbes have various mechanisms of metal sequestration that hold greater metal biosorption capacities. The goal of microbial biosorption is to remove and/or recover metals and metalloids from solutions, using living or dead biomass and their components. This review discusses the sources of toxic heavy metals and describes the groups of microorganisms with biosorbent potential for heavy metal removal. PMID:28106848

Gene expression profiling to identify the toxicities and potentially relevant human disease outcomes associated with environmental heavy metal exposure.

PubMed

Korashy, Hesham M; Attafi, Ibraheem M; Famulski, Konrad S; Bakheet, Saleh A; Hafez, Mohammed M; Alsaad, Abdulaziz M S; Al-Ghadeer, Abdul Rahman M

2017-02-01

Heavy metals are the most commonly encountered toxic substances that increase susceptibility to various diseases after prolonged exposure. We have previously shown that healthy volunteers living near a mining area had significant contamination with heavy metals associated with significant changes in the expression of some detoxifying genes, xenobiotic metabolizing enzymes, and DNA repair genes. However, alterations of most of the molecular target genes associated with diseases are still unknown. Thus, the aims of this study were to (a) evaluate the gene expression profile and (b) identify the toxicities and potentially relevant human disease outcomes associated with long-term human exposure to environmental heavy metals in mining area using microarray analysis. For this purpose, 40 healthy male volunteers who were residents of a heavy metal-polluted area (Mahd Al-Dhahab city, Saudi Arabia) and 20 healthy male volunteers who were residents of a non-heavy metal-polluted area were included in the study. Total RNA was isolated from whole blood using PAXgene Blood RNA tubes and then reversed transcribed and hybridized to the gene array using the Affymetrix U219 GeneChip. Microarray analysis showed about 2129 genes were identified and differentially altered, among which a shared set of 425 genes was differentially expressed in the heavy metal-exposed groups. Ingenuity pathway analysis revealed that the most altered gene-regulated diseases in heavy metal-exposed groups included hematological and developmental disorders and mostly renal and urological diseases. Quantitative real-time polymerase chain reaction closely matched the microarray data for some genes tested. Importantly, changes in gene-related diseases were attributed to alterations in the genes encoded for protein synthesis. Renal and urological diseases were the diseases that were most frequently associated with the heavy metal-exposed group. Therefore, there is a need for further studies to validate these genes, which could be used as early biomarkers to prevent renal injury. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ecological risk evaluation of combined pollution of herbicide siduron and heavy metals in soils.

PubMed

Jiang, Rong; Wang, Meie; Chen, Weiping; Li, Xuzhi

2018-06-01

Combined pollution of agrichemicals and heavy metals in urban lawn soils were commonly observed throughout the world, and the co-existed two chemicals could interact with each other both in environment behavior and toxic effect. However, little has been reported on the ecological risk of their combined pollution, especially in field due to lack of systematic methodology. In this study, four soils (C, N1, N2, N3) from two public parks in Beijing, China, with similar properties but contrasting heavy metal contaminated level were chosen to assess the ecological risks of co-existed herbicide siduron and heavy metals. Environmental behaviors of siduron in studied soils were investigated with batch experiments in lab, based on which the environmental exposure level of siduron was simulated with HYDRUS-1D. Results suggested that soil organic matter (SOM) rather than the co-existed heavy metals was the dominant factor affecting the fate and the accumulation of siduron in soils. Soil N2 with the highest SOM, showed the strongest tendency to retain siduron among the studied soils. Significant joint effect of siduron and heavy metals on cucumber root elongation was observed through lab experiments. Thus, the joint toxicity of siduron and heavy metals were calculated based on single toxicology data of them using independent action (IA) and concentration addition (CA) model. Then, the predicted no effect concentration (PNEC soil ) of siduron was calculated with equilibrium partitioning method and extrapolation techniques. The PNEC soil of siduron was the lowest in heaviest heavy metal contaminated soil N3. The risk characterization ratios (RCR) of siduron in four soils were all >1. The highest RCR of siduron in soil N3 suggested that it was the joint toxicity of siduron and heavy metals to organisms determining the ecological risks of siduron in combined polluted soils. Copyright © 2018 Elsevier B.V. All rights reserved.

Altered heavy metals and transketolase found in autistic spectrum disorder.

PubMed

Obrenovich, Mark E; Shamberger, Raymond J; Lonsdale, Derrick

2011-12-01

Autism and autism spectrum disorder (ASD) are developmental brain disorders with complex, obscure, and multifactorial etiology. Our recent clinical survey of patient records from ASD children under the age of 6 years and their age-matched controls revealed evidence of abnormal markers of thiol metabolism, as well as a significant alteration in deposition of several heavy metal species, particularly arsenic, mercury, copper, and iron in hair samples between the groups. Altered thiol metabolism from heavy metal toxicity may be responsible for the biochemical alterations in transketolase, and are mechanisms for oxidative stress production, dysautonomia, and abnormal thiamine homeostasis. It is unknown why the particular metals accumulate, but we suspect that children with ASD may have particular trouble excreting thiol-toxic heavy metal species, many of which exist as divalent cations. Accumulation or altered mercury clearance, as well as concomitant oxidative stress, arising from redox-active metal and arsenic toxicity, offers an intriguing component or possible mechanism for oxidative stress-mediated neurodegeneration in ASD patients. Taken together, these factors may be more important to the etiology of this symptomatically diverse disease spectrum and may offer insights into new treatment approaches and avenues of exploration for this devastating and growing disease.

Adsorption of heavy metal in freeway by asphalt block

NASA Astrophysics Data System (ADS)

Zheng, Chaocheng

2017-08-01

Heavy metals are toxic, persistent, and carcinogenic in freeway. Various techniques are available for the removal of heavy metals from waste water among soils during freeway including ion-exchange, membrane filtration, electrolysis, coagulation, flotation, and adsorption. Among them, bio-sorption processes are widely used for heavy metal and other pollutant removal due to its sustainable, rapid and economic. In this paper, heavy metal removal facilitated by adsorption in plants during freeway was illustrated to provide concise information on exploring the adsorption efficiency.

Effect of heavy metals on inhibition of root elongation in 23 cultivars of flax (Linum usitatissimum L.).

PubMed

Soudek, Petr; Katrusáková, Adéla; Sedlácek, Lukás; Petrová, Sárka; Kocí, Vladimír; Marsík, Petr; Griga, Miroslav; Vanek, Tomás

2010-08-01

The effect of toxic metals on seed germination was studied in 23 cultivars of flax (Linum usitatissimum L.). Toxicity of cadmium, cobalt, copper, zinc, nickel, lead, chromium, and arsenic at five different concentrations (0.01-1 mM) was tested by standard ecotoxicity test. Root length was measured after 72 h of incubation. Elongation inhibition, EC50 value, slope, and NOEC values were calculated. Results were evaluated by principal component analysis, a multidimensional statistical method. The results showed that heavy-metal toxicity decreased in the following order: As3+>or=As5+>Cu2+>Cd2+>Co2+>Cr6+>Ni2+>Pb2+>Cr3+>Zn2+.

Transition Metals and Virulence in Bacteria

PubMed Central

Palmer, Lauren D.; Skaar, Eric P.

2016-01-01

Transition metals are required trace elements for all forms of life. Due to their unique inorganic and redox properties, transition metals serve as cofactors for enzymes and other proteins. In bacterial pathogenesis, the vertebrate host represents a rich source of nutrient metals, and bacteria have evolved diverse metal acquisition strategies. Host metal homeostasis changes dramatically in response to bacterial infections, including production of metal sequestering proteins and the bombardment of bacteria with toxic levels of metals. Presumably, in response, bacteria have evolved systems to subvert metal sequestration and toxicity. The coevolution of hosts and their bacterial pathogens in the battle for metals has uncovered emerging paradigms in social microbiology, rapid evolution, host specificity, and metal homeostasis across domains. This review focuses on recent advances and open questions in our understanding of the complex role of transition metals at the host-pathogen interface. PMID:27617971

Transition Metals and Virulence in Bacteria.

PubMed

Palmer, Lauren D; Skaar, Eric P

2016-11-23

Transition metals are required trace elements for all forms of life. Due to their unique inorganic and redox properties, transition metals serve as cofactors for enzymes and other proteins. In bacterial pathogenesis, the vertebrate host represents a rich source of nutrient metals, and bacteria have evolved diverse metal acquisition strategies. Host metal homeostasis changes dramatically in response to bacterial infections, including production of metal sequestering proteins and the bombardment of bacteria with toxic levels of metals. In response, bacteria have evolved systems to subvert metal sequestration and toxicity. The coevolution of hosts and their bacterial pathogens in the battle for metals has uncovered emerging paradigms in social microbiology, rapid evolution, host specificity, and metal homeostasis across domains. This review focuses on recent advances and open questions in our understanding of the complex role of transition metals at the host-pathogen interface.

A poisonous surprise under the coat of the African crested rat

PubMed Central

Kingdon, Jonathan; Agwanda, Bernard; Kinnaird, Margaret; O'Brien, Timothy; Holland, Christopher; Gheysens, Thomas; Boulet-Audet, Maxime; Vollrath, Fritz

2012-01-01

Plant toxins are sequestered by many animals and the toxicity is frequently advertised by aposematic displays to deter potential predators. Such ‘unpalatability by appropriation’ is common in many invertebrate groups and also found in a few vertebrate groups. However, potentially lethal toxicity by acquisition has so far never been reported for a placental mammal. Here, we describe complex morphological structures and behaviours whereby the African crested rat, Lophiomys imhausi, acquires, dispenses and advertises deterrent toxin. Roots and bark of Acokanthera schimperi (Apocynaceae) trees are gnawed, masticated and slavered onto highly specialized hairs that wick up the compound, to be delivered whenever the animal is bitten or mouthed by a predator. The poison is a cardenolide, closely resembling ouabain, one of the active components in a traditional African arrow poison long celebrated for its power to kill elephants. PMID:21813554

Revealing the ability of a novel polysaccharide bioflocculant in bioremediation of heavy metals sensed in a Vibrio bioluminescence reporter assay.

PubMed

Sajayan, Arya; Seghal Kiran, G; Priyadharshini, S; Poulose, Navya; Selvin, Joseph

2017-09-01

A bioflocculant-producing bacterial strain, designated MSI021, was isolated from the marine sponge Dendrilla nigra and demonstrated 94% flocculation activity in a kaolin clay suspension. MSI021 was identified as Bacillus cereus based on phylogenetic affiliation and biochemical characteristics. The purified extra-cellular bioflocculant was chemically elucidated as a polysaccharide molecule. The polysaccharide bioflocculant was stable under both acidic and alkaline conditions (pH 2.0-10.0) and temperatures up to 100 °C. The purified bioflocculant efficiently nucleated the formation of silver nanoparticles which showed broad spectrum antibacterial activity. The ability of the bioflocculant to remediate heavy metal toxicity was evaluated by measuring the inhibition of bioluminescence expression in Vibrio harveyi. Enrichment of heavy metals such as zinc, mercury and copper at concentrations of 1, 2 and 3 mM in culture media showed significant reduction of bioluminescence in Vibrio, whereas media enriched with heavy metals and bioflocculant showed dose dependent improvement in the expression of bioluminescence. The assay results demonstrated that the polysaccharide bioflocculant effectively mitigates heavy metal toxicity, thereby improving the expression of bioluminescence in Vibrio. This bioluminescence reporter assay can be developed into a high-throughput format to monitor and evaluate of heavy metal toxicity. The findings of this study revealed that a novel polysaccharide bioflocculant produced by a marine B. cereus demonstrated strong flocculating performance and was effective in nucleating the formation antibacterial silver nanoparticles and removing heavy metals. These results suggest that the MSI021 polysaccharide bioflocculant can be used to develop greener waste water treatment systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ecological risk assessment of toxic organic pollutant and heavy metals in water and sediment from a landscape lake in Tianjin City, China.

PubMed

Zhang, Ying; Liu, Yuanyuan; Niu, Zhiguang; Jin, Shaopei

2017-05-01

To estimate the ecological risk of toxic organic pollutant (formaldehyde) and heavy metals (mercury (Hg), arsenic (As), cadmium (Cd), and chromium (Cr)) in water and sediment from a landscape Lake in Tianjin City, an ecological risk assessment was performed. The risk quotient (RQ) method and the AQUATOX model were used to assess the ecological risk of formaldehyde in landscape water. Meanwhile, the RQ method and the potential ecological risk index method were used to assess the ecological risk of four heavy metals in water and sediment from the studied landscape lake, respectively. The results revealed that the maximum concentration of formaldehyde in landscape water was lower than the environmental quality standards of surface water in China. The maximum simulated concentrations of formaldehyde in phytoplankton and invertebrates were 3.15 and 22.91 μg/L, respectively, which were far less than its toxicity data values (1000 and 510 μg/L, respectively), suggesting that formaldehyde in landscape water was at a safe level for aquatic organisms. The RQ model indicated that the risks of phytoplankton and invertebrates were higher than that of fish posed by Hg and Cd in landscape water, and the risks from As and Cr were acceptable for all test organisms. Cd is the most important pollution factor among all heavy metals in sediment from studied landscape lake, and the pollution factor sequence of heavy metals was Hg > As > Cr > Cd. The values of risk index (RI) for four heavy metals in samples a and b were 43.48 and 72.66, which were much lower than the threshold value (150), suggesting that the ecological risk posed by heavy metals in sediment was negligible.

Heavy metal driven co-selection of antibiotic resistance in soil and water bodies impacted by agriculture and aquaculture.

PubMed

Seiler, Claudia; Berendonk, Thomas U

2012-01-01

The use of antibiotic agents as growth promoters was banned in animal husbandry to prevent the selection and spread of antibiotic resistance. However, in addition to antibiotic agents, heavy metals used in animal farming and aquaculture might promote the spread of antibiotic resistance via co-selection. To investigate which heavy metals are likely to co-select for antibiotic resistance in soil and water, the available data on heavy metal pollution, heavy metal toxicity, heavy metal tolerance, and co-selection mechanisms was reviewed. Additionally, the risk of metal driven co-selection of antibiotic resistance in the environment was assessed based on heavy metal concentrations that potentially induce this co-selection process. Analyses of the data indicate that agricultural and aquacultural practices represent major sources of soil and water contamination with moderately to highly toxic metals such as mercury (Hg), cadmium (Cd), copper (Cu), and zinc (Zn). If those metals reach the environment and accumulate to critical concentrations they can trigger co-selection of antibiotic resistance. Furthermore, co-selection mechanisms for these heavy metals and clinically as well as veterinary relevant antibiotics have been described. Therefore, studies investigating co-selection in environments impacted by agriculture and aquaculture should focus on Hg, Cd, Cu, and Zn as selecting heavy metals. Nevertheless, the respective environmental background has to be taken into account.

Heavy metal driven co-selection of antibiotic resistance in soil and water bodies impacted by agriculture and aquaculture

PubMed Central

Seiler, Claudia; Berendonk, Thomas U.

2012-01-01

The use of antibiotic agents as growth promoters was banned in animal husbandry to prevent the selection and spread of antibiotic resistance. However, in addition to antibiotic agents, heavy metals used in animal farming and aquaculture might promote the spread of antibiotic resistance via co-selection. To investigate which heavy metals are likely to co-select for antibiotic resistance in soil and water, the available data on heavy metal pollution, heavy metal toxicity, heavy metal tolerance, and co-selection mechanisms was reviewed. Additionally, the risk of metal driven co-selection of antibiotic resistance in the environment was assessed based on heavy metal concentrations that potentially induce this co-selection process. Analyses of the data indicate that agricultural and aquacultural practices represent major sources of soil and water contamination with moderately to highly toxic metals such as mercury (Hg), cadmium (Cd), copper (Cu), and zinc (Zn). If those metals reach the environment and accumulate to critical concentrations they can trigger co-selection of antibiotic resistance. Furthermore, co-selection mechanisms for these heavy metals and clinically as well as veterinary relevant antibiotics have been described. Therefore, studies investigating co-selection in environments impacted by agriculture and aquaculture should focus on Hg, Cd, Cu, and Zn as selecting heavy metals. Nevertheless, the respective environmental background has to be taken into account. PMID:23248620

Baby Teeth Link Autism and Heavy Metals, NIH Study Suggests

MedlinePlus

... Release Thursday, June 1, 2017 Baby teeth link autism and heavy metals, NIH study suggests Cross-section ... Sinai Health System Baby teeth from children with autism contain more toxic lead and less of the ...

Environmental Pollution Studies in an Underdeveloped Country: (1) Heavy Metal Pollution in Ibadan, Nigeria.

ERIC Educational Resources Information Center

Onianwa, P. C.

1993-01-01

Reviews research studies related to the monitoring of trace heavy metals in environmental samples such as plants, water, soils, and other natural resources in the city of Ibadan, Nigeria. Research results indicate a significant increase in toxic heavy metal levels has occurred, implying the need for environmental education. (Contains 31…

Challenges and opportunities in the phytoremediation of heavy metals contaminated soils: A review.

PubMed

Mahar, Amanullah; Wang, Ping; Ali, Amjad; Awasthi, Mukesh Kumar; Lahori, Altaf Hussain; Wang, Quan; Li, Ronghua; Zhang, Zengqiang

2016-04-01

Mining operations, industrial production and domestic and agricultural use of metal and metal containing compound have resulted in the release of toxic metals into the environment. Metal pollution has serious implications for the human health and the environment. Few heavy metals are toxic and lethal in trace concentrations and can be teratogenic, mutagenic, endocrine disruptors while others can cause behavioral and neurological disorders among infants and children. Therefore, remediation of heavy metals contaminated soil could be the only effective option to reduce the negative effects on ecosystem health. Thus, keeping in view the above facts, an attempt has been made in this article to review the current status, challenges and opportunities in the phytoremediation for remediating heavy metals from contaminated soils. The prime focus is given to phytoextraction and phytostabilization as the most promising and alternative methods for soil reclamation. Copyright © 2015 Elsevier Inc. All rights reserved.

The handling, hazards, and maintenance of heavy liquids in the geologic laboratory

USGS Publications Warehouse

Hauff, Phoebe L.; Airey, Joseph

1980-01-01

In geologic laboratories the organic heavy liquids bromoform, methylene iodide, tetrabromoethane, and clerici compounds have been used for years in mineral separation processes. Because the volume of use of these compounds is low, insufficient data is available on their toxic properties. This report is an attempt to summarize the known data from published and industry sources. The physical properties, hazards of handling,proper storage facilities, and adequate protective Clothing are discussed for each compound as well as for their common and less-common solvents. Toxicity data for these materials is listed along with exposure symptoms and suggested first aid treatments. Safety for the worker is emphasized. Three reclamation methods which recover the solvent used as a dilutant and purify the heavy liquid are discussed and illustrated. These include: the water cascade, re fluxing-distillation-condensation, and flash evaporation methods. Various techniques for restoration and stabilization of these heavy liquids are also included.

Metal-contaminated soil remediation by using sludges of the marble industry: toxicological evaluation.

PubMed

Pérez-Sirvent, C; García-Lorenzo, M L; Martínez-Sánchez, M J; Navarro, M C; Marimón, J; Bech, J

2007-05-01

The major risks due to metal pollution of sediments consist of leaching to groundwater and potential toxicity to animals and/or plants. The objective of this study was to evaluate by means of an ecotoxicological approach the effects of the addition of cutting marble sludges on the mobile metal fraction of sediments polluted with heavy metals. The study was carried out on two sediments derived from mining activities in Portman Bay (SE, Spain) polluted by heavy metals. These sediments were mixed with sludges left after the cutting of marble. The results obtained by leaching experiments showed that the addition of marble cutting sludge, consisting mainly of carbonates, to a heavy-metal polluted sediment produces a decrease of available metal forms. The carbonate content seems to play a role in chemical stabilisation of metals and in a decrease of toxicity of sediments. The leached solutions have a non-toxic effect. The mild remediation by addition of sludge has moreover effects to long term.

In situ and laboratory bioassays with Chironomus riparius larvae to assess toxicity of metal contamination in rivers: the relative toxic effect of sediment versus water contamination.

PubMed

Faria, Mafalda S; Lopes, Ricardo J; Nogueira, António J A; Soares, Amadeu M V M

2007-09-01

We used bioassays employing head capsule width and body length increase of Chironomus riparius larvae as end points to evaluate metal contamination in streams. Bioassays were performed in situ near an abandoned Portuguese goldmine in the spring of 2003 and 2004. Bioassays also were performed under laboratory conditions with water and sediment collected from each stream to verify if laboratory bioassays could detect in situ toxicity and to evaluate the relative contribution of sediment and water to overall toxicity. We used field sediments with control water and control sediments with field water to discriminate between metal contamination in water and sediment. Field water with dry and sieved, organic matter-free, and nontreated sediments was used to determine the toxicity of heavy metals that enter the organism through ingested material. In both in situ and laboratory bioassays, body length increase was significantly inhibited by metal contamination, whereas head capsule width was not affected. Body length increase was more affected by contaminated sediment compared to contaminated water. The lowest-effect level of heavy metals was observed in the dry and sieved sediment that prevented ingestion of sediment particles by larvae. These results suggest that body length increase of C. riparius larvae can be used to indicate the impact of metal contamination in rivers. Chironomus riparius larvae are more affected by heavy metals that enter the organism through ingested sediment than by heavy metals dissolved in the water column. Nevertheless, several factors, such as the particle size and organic matter of sediment, must be taken into account.

Trehalose 6,6′-Dimycolate and Lipid in the Pathogenesis of Caseating Granulomas of Tuberculosis in Mice

PubMed Central

Hunter, Robert L.; Olsen, Margaret; Jagannath, Chinnaswamy; Actor, Jeffrey K.

2006-01-01

Trehalose 6,6′-dimycolate (TDM) is the most abundant, most granulomagenic, and most toxic lipid extractable from the surface of virulent Mycobacterium tuberculosis (MTB). We further examined its toxicity, which requires activation by oily surfaces. Injections of MTB and/or TDM into sensitized mice induced caseating granulomas that centered on oil droplets. If large doses of MTB were injected in saline, caseating granulomas developed in adipose tissue, but MTB with surface TDM removed induced only acute inflammation that did not persist. Variations in protocols produced several variants of caseating granulomas, each with characteristics of human tuberculosis. In each instance, MTB were localized in fat cells or oil drops during initiation of caseating granulomas suggesting that necrosis was caused by activation of the toxicity of TDM toxicity. Evidence extending these findings to the lung was derived from the observation that in sensitized mice, as in humans, tuberculosis development stimulates accumulation of lipid selectively in alveoli. MTB preferentially associated with lipid droplets in developing necrotic foci in late-stage murine tuberculosis. This supports the hypothesis that pulmonary tuberculosis sequesters MTB in a protected environment that accumulates lipid until it is able to activate the toxicity of TDM and initiate necrosis that results in caseating granulomas. PMID:16565499

Ultra-Low Carbon Emissions from Coal-Fired Power Plants through Bio-Oil Co-Firing and Biochar Sequestration.

PubMed

Dang, Qi; Mba Wright, Mark; Brown, Robert C

2015-12-15

This study investigates a novel strategy of reducing carbon emissions from coal-fired power plants through co-firing bio-oil and sequestering biochar in agricultural lands. The heavy end fraction of bio-oil recovered from corn stover fast pyrolysis is blended and co-fired with bituminous coal to form a bio-oil co-firing fuel (BCF). Life-cycle greenhouse gas (GHG) emissions per kWh electricity produced vary from 1.02 to 0.26 kg CO2-eq among different cases, with BCF heavy end fractions ranging from 10% to 60%, which corresponds to a GHG emissions reduction of 2.9% to 74.9% compared with that from traditional bituminous coal power plants. We found a heavy end fraction between 34.8% and 37.3% is required to meet the Clean Power Plan's emission regulation for new coal-fired power plants. The minimum electricity selling prices are predicted to increase from 8.8 to 14.9 cents/kWh, with heavy end fractions ranging from 30% to 60%. A minimum carbon price of $67.4 ± 13 per metric ton of CO2-eq was estimated to make BCF power commercially viable for the base case. These results suggest that BCF co-firing is an attractive pathway for clean power generation in existing power plants with a potential for significant reductions in carbon emissions.

Mercury-Pollution Induction of Intracellular Lipid Accumulation and Lysosomal Compartment Amplification in the Benthic Foraminifer Ammonia parkinsoniana

PubMed Central

Curzi, Davide; Cesarini, Erica; Canonico, Barbara; Giordano, Francesco M.; De Matteis, Rita; Bernhard, Joan M.; Pieretti, Nadia; Gu, Baohua; Eskelsen, Jeremy R.; Jubb, Aaron M.; Zhao, Linduo; Pierce, Eric M.; Gobbi, Pietro; Papa, Stefano; Coccioni, Rodolfo

2016-01-01

Heavy metals such as mercury (Hg) pose a significant health hazard through bioaccumulation and biomagnification. By penetrating cell membranes, heavy metal ions may lead to pathological conditions. Here we examined the responses of Ammonia parkinsoniana, a benthic foraminiferan, to different concentrations of Hg in the artificial sea water. Confocal images of untreated and treated specimens using fluorescent probes (Nile Red and Acridine Orange) provided an opportunity for visualizing the intracellular lipid accumulation and acidic compartment regulation. With increased Hg over time, we observed an increased number of lipid droplets, which may have acted as a detoxifying organelle where Hg is sequestered and biologically inactivated. Further, Hg seems to promote the proliferation of lysosomes both in terms of number and dimension that, at the highest level of Hg, resulted in cell death. We report, for the first time, the presence of Hg within the foraminiferal cell: at the basal part of pores, in the organic linings of the foramen/septa, and as cytoplasmic accumulations. PMID:27603511

Quantitative assessment on soil enzyme activities of heavy metal contaminated soils with various soil properties.

PubMed

Xian, Yu; Wang, Meie; Chen, Weiping

2015-11-01

Soil enzyme activities are greatly influenced by soil properties and could be significant indicators of heavy metal toxicity in soil for bioavailability assessment. Two groups of experiments were conducted to determine the joint effects of heavy metals and soil properties on soil enzyme activities. Results showed that arylsulfatase was the most sensitive soil enzyme and could be used as an indicator to study the enzymatic toxicity of heavy metals under various soil properties. Soil organic matter (SOM) was the dominant factor affecting the activity of arylsulfatase in soil. A quantitative model was derived to predict the changes of arylsulfatase activity with SOM content. When the soil organic matter content was less than the critical point A (1.05% in our study), the arylsulfatase activity dropped rapidly. When the soil organic matter content was greater than the critical point A, the arylsulfatase activity gradually rose to higher levels showing that instead of harm the soil microbial activities were enhanced. The SOM content needs to be over the critical point B (2.42% in our study) to protect its microbial community from harm due to the severe Pb pollution (500mgkg(-1) in our study). The quantitative model revealed the pattern of variation of enzymatic toxicity due to heavy metals under various SOM contents. The applicability of the model under wider soil properties need to be tested. The model however may provide a methodological basis for ecological risk assessment of heavy metals in soil. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mercury Toxicity and Treatment: A Review of the Literature

PubMed Central

Bernhoft, Robin A.

2012-01-01

Mercury is a toxic heavy metal which is widely dispersed in nature. Most human exposure results from fish consumption or dental amalgam. Mercury occurs in several chemical forms, with complex pharmacokinetics. Mercury is capable of inducing a wide range of clinical presentations. Diagnosis of mercury toxicity can be challenging but can be obtained with reasonable reliability. Effective therapies for clinical toxicity have been described. PMID:22235210

Sludge-Treated Coal Mine Spoils Increase Heavy metals in Cover Crops

Treesearch

F. C. McBride; C. Chavengsaksongkram; D. H. Urie

1977-01-01

Four species of forage were grown in a greenhouse on acid strip mine spoil treated with municipal sewage sludge. Foliar levels of heavy metals exceeded those recommended for animal consumption. No plant toxicity symptoms were evident.

Acute and chronic effects of heavy metals and cyanide on Mysidopsis bahia (crustacea:mysidacea)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lussier, S.M.; Gentile, J.H.; Walker, J.

1985-01-01

Acute and whole life-cycle toxicity tests were conducted with the estuarine mysid shrimp, Mysidopsis bahia, exposed to cyanide and selected heavy metals. Acute toxicity values (96h LC50) ranged from 3.5 micrograms/1 for mercury to 3130 micrograms/1 for lead, and were ranked in order of toxicity: (greatest)Hg, Cd, Cu, Cn, Ag, Sn, Ni, As, Cr, and Pb(least). The chronic toxicity values ranged from 1.2 micrograms/1 for mercury to 893 micrograms/1 for arsenic. Chronic values were calculated from either survival, time to first reproduction, or number of young produced. When acute toxicity data for the same chemical are compared, M. bahia ismore » consistently among the more sensitive marine species. Lack of comparable data precludes a similar observation with chronic tests. Examination of the relative sensitivity of the chronic responses indicates that only for cadmium was survival more sensitive than reproduction.« less

Performance of rose scented geranium (Pelargonium graveolens) in heavy metal polluted soil vis-à-vis phytoaccumulation of metals.

PubMed

Chand, Sukhmal; Singh, Geetu; Patra, D D

2016-08-02

An investigation was carried out to evaluate the effect of heavy metal toxicity on growth, herb, oil yield and quality and metal accumulation in rose scented geranium (Pelargonium graveolens) grown in heavy metal enriched soils. Four heavy metals (Cd, Ni, Cr, and Pb) each at two levels (10 and 20 mg kg-1 soil) were tested on geranium. Results indicated that Cr concentration in soil at 20 mg kg-1 reduced leaves, stem and root yield by 70, 83, and 45%, respectively, over control. Root growth was significantly affected in Cr stressed soil. Nickel, Cr, and Cd concentration and accumulation in plant increased with higher application of these metals. Chromium, nickel and cadmium uptake was observed to be higher in leaves than in stem and roots. Essential oil constituents were generally not significantly affected by heavy metals except Pb at 10 and 20 ppm, which significantly increased the content of citronellol and Ni at 20 ppm increased the content of geraniol. Looking in to the higher accumulation of toxic metals by geranium and the minimal impact of heavy metals on quality of essential oil, geranium can be commercially cultivated in heavy metal polluted soil for production of high value essential oil.

Heavy metals in contaminated environment: Destiny of secondary metabolite biosynthesis, oxidative status and phytoextraction in medicinal plants.

PubMed

Asgari Lajayer, Behnam; Ghorbanpour, Mansour; Nikabadi, Shahab

2017-11-01

Contamination of soils, water and air with toxic heavy metals by various human activities is a crucial environmental problem in both developing and developed countries. Heavy metals could be introduced into medicinal plant products through contaminated environment (soil, water and air resources) and/or poor production practices. Growing of medicinal plants in heavy metal polluted environments may eventually affect the biosynthesis of secondary metabolites, causing significant changes in the quantity and quality of these compounds. Certain medicinal and aromatic plants can absorb and accumulate metal contaminants in the harvestable foliage and, therefore, considered to be a feasible alternative for remediation of polluted sites without any contamination of essential oils. Plants use different strategies and complex arrays of enzymatic and non-enzymatic anti-oxidative defense systems to cope with overproduction of ROS causes from the heavy metals entered their cells through foliar and/or root systems. This review summarizes the reports of recent investigations involving heavy metal accumulation by medicinal plants and its effects on elicitation of secondary metabolites, toxicity and detoxification pathways, international standards regarding in plants and plant-based products, and human health risk assessment of heavy metals in soil-medicinal plants systems. Copyright © 2017 Elsevier Inc. All rights reserved.

Enhancement of cadmium ion sorption capacity of lignocellulosic bio-sorbent by sulfonation

Treesearch

Eun W. Shin; James S. Han; Roger M. Rowell; Soo-Hong Min; James O. Peterson

2003-01-01

Water contaminated by heavy metals remains a serious environmental and public health problem. Cadmium is a toxic heavy metal that not only causes choking, abdominal pain, anemia, renal dysfunction, and diarrhea, but also has been listed as a carcinogen by the EPA (Gaballah and Kibertus, 1998). Among current technologies used to reduce the amount of heavy metals in...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bae, Wookeun; Shin, Eung Bai; Lee, Kil Chul

The potential hazard of landfill wastes was previously evaluated by examining the extraction procedures for individual waste, although various wastes were co-disposed of in actual landfills. This paper investigates the reduction of extraction-procedure toxicity by co-disposing various combinations of two wastes. When two wastes are mixed homogeneously, the extraction of heavy metals from the waste mixture is critically affected by the extract pH. Thus, co-disposal wastes will have a resultant pH between the pH values of its constituent. The lower the resultant pH, the lower the concentrations of heavy metals in the extract. When these wastes are extracted sequentially, themore » latter extracted waste has a stronger influence on the final concentration of heavy metals in the extract. Small-scale lysimeter experiments confirm that when heavy-metal-bearing leachates Generated from hazardous-waste lysimeters are passed through a nonhazardous-waste lysimeter filled with compost, briquette ash, or refuse-incineration ashes, the heavy-metal concentration in the final leachates decreases significantly. Thus, the heavy-metal leaching could be attenuated if a less extraction-procedure-toxic waste were placed at the bottom of a landfill. 3 refs., 4 figs., 5 tabs.« less

Heavy Metal Poisoning and Cardiovascular Disease

PubMed Central

Alissa, Eman M.; Ferns, Gordon A.

2011-01-01

Cardiovascular disease (CVD) is an increasing world health problem. Traditional risk factors fail to account for all deaths from CVD. It is mainly the environmental, dietary and lifestyle behavioral factors that are the control keys in the progress of this disease. The potential association between chronic heavy metal exposure, like arsenic, lead, cadmium, mercury, and CVD has been less well defined. The mechanism through which heavy metals act to increase cardiovascular risk factors may act still remains unknown, although impaired antioxidants metabolism and oxidative stress may play a role. However, the exact mechanism of CVD induced by heavy metals deserves further investigation either through animal experiments or through molecular and cellular studies. Furthermore, large-scale prospective studies with follow up on general populations using appropriate biomarkers and cardiovascular endpoints might be recommended to identify the factors that predispose to heavy metals toxicity in CVD. In this review, we will give a brief summary of heavy metals homeostasis, followed by a description of the available evidence for their link with CVD and the proposed mechanisms of action by which their toxic effects might be explained. Finally, suspected interactions between genetic, nutritional and environmental factors are discussed. PMID:21912545

Lead toxicity induces autophagy to protect against cell death through mTORC1 pathway in cardiofibroblasts

PubMed Central

Sui, Li; Zhang, Rui-Hong; Zhang, Ping; Yun, Ke-Li; Zhang, Hong-Cai; Liu, Li; Hu, Ming-Xu

2015-01-01

Heavy metals, such as lead (Pb2+), are usually accumulated in human bodies and impair human's health. Lead is a metal with many recognized adverse health side effects and yet the molecular processes underlying lead toxicity are still poorly understood. In the present study, we proposed to investigate the effects of lead toxicity in cultured cardiofibroblasts. After lead treatment, cultured cardiofibroblasts showed severe endoplasmic reticulum (ER) stress. However, the lead-treated cardiofibroblasts were not dramatically apoptotic. Further, we found that these cells determined to undergo autophagy through inhibiting mammalian target of rapamycin complex 1 (mTORC1) pathway. Moreover, inhibition of autophagy by 3-methyladenine (3-MA) may dramatically enhance lead toxicity in cardiofibroblasts and cause cell death. Our data establish that lead toxicity induces cell stress in cardiofibroblasts and protective autophagy is activated by inhibition of mTORC1 pathway. These findings describe a mechanism by which lead toxicity may promote the autophagy of cardiofibroblasts cells, which protects cells from cell stress. Our findings provide evidence that autophagy may help cells to survive under ER stress conditions in cardiofibroblasts and may set up an effective therapeutic strategy for heavy metal toxicity. PMID:25686247

Lead toxicity induces autophagy to protect against cell death through mTORC1 pathway in cardiofibroblasts.

PubMed

Sui, Li; Zhang, Rui-Hong; Zhang, Ping; Yun, Ke-Li; Zhang, Hong-Cai; Liu, Li; Hu, Ming-Xu

2015-03-31

Heavy metals, such as lead (Pb(2+)), are usually accumulated in human bodies and impair human's health. Lead is a metal with many recognized adverse health side effects and yet the molecular processes underlying lead toxicity are still poorly understood. In the present study, we proposed to investigate the effects of lead toxicity in cultured cardiofibroblasts. After lead treatment, cultured cardiofibroblasts showed severe endoplasmic reticulum (ER) stress. However, the lead-treated cardiofibroblasts were not dramatically apoptotic. Further, we found that these cells determined to undergo autophagy through inhibiting mammalian target of rapamycin complex 1 (mTORC1) pathway. Moreover, inhibition of autophagy by 3-methyladenine (3-MA) may dramatically enhance lead toxicity in cardiofibroblasts and cause cell death. Our data establish that lead toxicity induces cell stress in cardiofibroblasts and protective autophagy is activated by inhibition of mTORC1 pathway. These findings describe a mechanism by which lead toxicity may promote the autophagy of cardiofibroblasts cells, which protects cells from cell stress. Our findings provide evidence that autophagy may help cells to survive under ER stress conditions in cardiofibroblasts and may set up an effective therapeutic strategy for heavy metal toxicity.

Characterization of heavy metal concentrations in the sediments of three freshwater rivers in Huludao City, Northeast China.

PubMed

Zheng, Na; Wang, Qichao; Liang, Zhongzhu; Zheng, Dongmei

2008-07-01

Wuli River, Cishan River, and Lianshan River are three freshwater rivers flowing through Huludao City, in a region of northeast China strongly affected by industrialization. Contamination assessment has never been conducted in a comprehensive way. For the first time, the contamination of three rivers impacted by different sources in the same city was compared. This work investigated the distribution and sources of Hg, Pb, Cd, Zn and Cu in the surface sediments of Wuli River, Cishan River, and Lianshan River, and assessed heavy metal toxicity risk with the application of two different sets of Sediment Quality Guideline (SQG) indices (effect range low/effect range median values, ERL/ERM; and threshold effect level/probable effect level, TEL/PEL). Furthermore, this study used a toxic unit approach to compare and gauge the individual and combined metal contamination for Hg, Pb, Cd, Zn and Cu. Results showed that Hg contamination in the sediments of Wuli River originated from previous sediment contamination of the chlor-alkali producing industry, and Pb, Cd, Zn and Cu contamination was mainly derived from atmospheric deposition and unknown small pollution sources. Heavy metal contamination to Cishan River sediments was mainly derived from Huludao Zinc Plant, while atmospheric deposition, sewage wastewater and unknown small pollution were the primary sources for Lianshan River. The potential acute toxicity in sediment of Wuli River may be primarily due to Hg contamination. Hg is the major toxicity contributor, accounting for 53.3-93.2%, 7.9-54.9% to total toxicity in Wuli River and Lianshan River, respectively, followed by Cd. In Cishan River, Cd is the major sediment toxicity contributor, however, accounting for 63.2-66.9% of total toxicity.

Application of carbon foam for heavy metal removal from industrial plating wastewater and toxicity evaluation of the adsorbent.

PubMed

Lee, Chang-Gu; Song, Mi-Kyung; Ryu, Jae-Chun; Park, Chanhyuk; Choi, Jae-Woo; Lee, Sang-Hyup

2016-06-01

Electroplating wastewater contains various types of toxic substances, such as heavy metals, solvents, and cleaning agents. Carbon foam was used as an adsorbent for the removal of heavy metals from real industrial plating wastewater. Its sorption capacity was compared with those of a commercial ion-exchange resin (BC258) and a heavy metal adsorbent (CupriSorb™) in a batch system. The experimental carbon foam has a considerably higher sorption capacity for Cr and Cu than commercial adsorbents for acid/alkali wastewater and cyanide wastewater. Additionally, cytotoxicity test showed that the newly developed adsorbent has low cytotoxic effects on three kinds of human cells. In a pilot plant, the carbon foam had higher sorption capacity for Cr (73.64 g kg(-1)) than for Cu (14.86 g kg(-1)) and Ni (7.74 g kg(-1)) during 350 h of operation time. Oxidation pretreatments using UV/hydrogen peroxide enhance heavy metal removal from plating wastewater containing cyanide compounds. Copyright © 2016 Elsevier Ltd. All rights reserved.

Short-time effect of heavy metals upon microbial community activity.

PubMed

Wang, Fei; Yao, Jun; Si, Yang; Chen, Huilun; Russel, Mohammad; Chen, Ke; Qian, Yiguang; Zaray, Gyula; Bramanti, Emilia

2010-01-15

Microcalorimetry was applied to assess and compare the toxic effect of heavy metals, such as As, Cu, Cd, Cr, Co, Pb and Zn, on the soil microbial activities and community. About 1.0 g soil spiked 5.0mg glucose and 5.0mg ammonium sulfate, the microbial activities were recorded as power-time curves, and their indices, microbial growth rate constant k, total heat evolution Q(T), metabolic enthalpy Delta H(met) and mass specific heat rate J(Q/S), were calculated. Comparing these thermodynamic parameters associated with growth yield, a general order of toxicity to the soil was found to be Cr>Pb>As>Co>Zn>Cd>Cu. When soil was exposed to heavy metals, the amount of bacteria and fungi decreased with the incubation time, and the bacterial number diminished sharply. It illustrates that fungi are more tolerant, and bacteria-fungi ratio would be altered under metal stress. To determine the status of the glucose consumed, a glucose biosensor with eggshell membrane was used to measure the remaining glucose in soil sample. Results showed that the time at which glucose was consumed completely was agreed with the microcalorimetric time to a large extent, and depended on the toxicity of heavy metals as well.

Coal burning leaves toxic heavy metal legacy in the Arctic

DOE Office of Scientific and Technical Information (OSTI.GOV)

McConnell, J.R.; Edwards, R.

2008-08-26

Toxic heavy metals emitted by industrial activities in the midlatitudes are transported through the atmosphere and deposited in the polar regions; bioconcentration and biomagnification in the food chain mean that even low levels of atmospheric deposition may threaten human health and Arctic ecosystems. Little is known about sources and long-term trends of most heavy metals before approximate to 1980, when modern measurements began, although heavy-metal pollution in the Arctic was widespread during recent decades. Lacking detailed, long-term measurements until now, ecologists, health researchers, and policy makers generally have assumed that contamination was highest during the 1960s and 1970s peak ofmore » industrial activity in North America and Europe. We present continuous 1772-2003 monthly and annually averaged deposition records for highly toxic thallium, cadmium, and lead from a Greenland ice core showing that atmospheric deposition was much higher than expected in the early 20th century, with tenfold increases from preindustrial levels by the early 1900s that were two to five times higher than during recent decades. Tracer measurements indicate that coal burning in North America and Europe was the likely source of these metals in the Arctic after 1860. Although these results show that heavy-metal pollution in the North Atlantic sector of the Arctic is substantially lower today than a century ago, contamination of other sectors may be increasing because of the rapid coal-driven growth of Asian economies.« less

Deposition behavior, risk assessment and source identification of heavy metals in reservoir sediments of Northeast China.

PubMed

Zhu, Lin; Liu, Jianwei; Xu, Shiguo; Xie, Zaigang

2017-08-01

Sediment cores from five reservoirs, located in the Liaoning and Jilin Provinces in Northeast China, were collected to investigate the accumulation and potential toxicity of heavy metals (Fe, Mn, Cu, Cd, Pb, Zn, and Cr) during a sampling campaign in February, 2015. The results showed that all the detected metals accumulated significantly, especially Cd, compared to their respective background values. Among these reservoirs, Biliuhe Reservoir had markedly increasing trends for organic matter and all the metals, among which Mn was elevated by 280% to 3411mg/kg in a core of only 18cm in depth. Xinlicheng Reservoir was characterized by heavy siltation and varying metal distribution due to its regular geometric features and pulsed flood events. The Enrichment factor (EF) and geo-accumulation index (I geo ) indicated Cd was strongly enriched by anthropogenic inputs, with the values of EF and I geo greater than 8 and 3, respectively. The toxicity assessment calculated using consensus-based sediment quality guidelines (SQGs) implied the whole cores of Tanghe and Dahuofang and the upper cores of Biliuhe, Xinlicheng and Fengman exhibited toxicity to sediment-dwelling organisms. Cr contributed more to Q m-PEC than the other heavy metals, because only Cr exceeded the probable effect concentration (PEC) despite its low enrichment. According to the results of correlation analysis (CA) and principal components analysis (PCA), mining industries and agricultural activities within the basin were the main anthropogenic pollution sources for these heavy metals. Copyright © 2017 Elsevier Inc. All rights reserved.

Some Case Studies on Metal-Microbe Interactions to Remediate Heavy Metals- Contaminated Soils in Korea

NASA Astrophysics Data System (ADS)

Chon, Hyo-Taek

2015-04-01

Conventional physicochemical technologies to remediate heavy metals-contaminated soil have many problems such as low efficiency, high cost and occurrence of byproducts. Recently bioremediation technology is getting more and more attention. Bioremediation is defined as the use of biological methods to remediate and/or restore the contaminated land. The objectives of bioremediation are to degrade hazardous organic contaminants and to convert hazardous inorganic contaminants to less toxic compounds of safe levels. The use of bioremediation in the treatment of heavy metals in soils is a relatively new concept. Bioremediation using microbes has been developed to remove toxic heavy metals from contaminated soils in laboratory scale to the contaminated field sites. Recently the application of cost-effective and environment-friendly bioremediation technology to the heavy metals-contaminated sites has been gradually realized in Korea. The merits of bioremediation include low cost, natural process, minimal exposure to the contaminants, and minimum amount of equipment. The limitations of bioremediation are length of remediation, long monitoring time, and, sometimes, toxicity of byproducts for especially organic contaminants. From now on, it is necessary to prove applicability of the technologies to contaminated sites and to establish highly effective, low-cost and easy bioremediation technology. Four categories of metal-microbe interactions are generally biosorption, bioreduction, biomineralization and bioleaching. In this paper, some case studies of the above metal-microbe interactions in author's lab which were published recently in domestic and international journals will be introduced and summarized.

Protein Misfolding Diseases.

PubMed

Hartl, F Ulrich

2017-06-20

The majority of protein molecules must fold into defined three-dimensional structures to acquire functional activity. However, protein chains can adopt a multitude of conformational states, and their biologically active conformation is often only marginally stable. Metastable proteins tend to populate misfolded species that are prone to forming toxic aggregates, including soluble oligomers and fibrillar amyloid deposits, which are linked with neurodegeneration in Alzheimer and Parkinson disease, and many other pathologies. To prevent or regulate protein aggregation, all cells contain an extensive protein homeostasis (or proteostasis) network comprising molecular chaperones and other factors. These defense systems tend to decline during aging, facilitating the manifestation of aggregate deposition diseases. This volume of the Annual Review of Biochemistry contains a set of three articles addressing our current understanding of the structures of pathological protein aggregates and their associated disease mechanisms. These articles also discuss recent insights into the strategies cells have evolved to neutralize toxic aggregates by sequestering them in specific cellular locations.

MICROBIAL SEQUESTRATION OF LEAD AND OTHER HEAVY METALS

EPA Science Inventory

Human activity resulting in heavy metal contamination is a worldwide concern. Lead is a potent neurotoxin that can cause heart problems, kidney damage, and mental retardation. Mercury causes toxicity based on its form and route of exposure. Effects range from allergic reactions t...

Effects of heavy metals on plants and resistance mechanisms. A state-of-the-art report with special reference to literature published in Chinese journals.

PubMed

Cheng, Shuiping

2003-01-01

As one of the consequences of heavy metal pollution in soil, water and air, plants are contaminated by heavy metals in some parts of China. To understand the effects of heavy metals upon plants and the resistance mechanisms, would make it possible to use plants for cleaning and remediating heavy metal-polluted sites. The research results on the effects of heavy metals on plants and resistant mechanisms are compiled from Chinese publications from scientific journals and university journals, mostly published during the last decade. Effects of heavy metals on plants result in growth inhibition, structure damage, a decline of physiological and biochemical activities as well as of the function of plants. The effects and bioavailability of heavy metals depend on many factors, such as environmental conditions, pH, species of element, organic substances of the media and fertilization, plant species. But, there are also studies on plant resistance mechanisms to protect plants against the toxic effects of heavy metals such as combining heavy metals by proteins and expressing of detoxifying enzyme and nucleic acid, these mechanisms are integrated to protect the plants against injury by heavy metals. There are two aspects on the interaction of plants and heavy metals. On one hand, heavy metals show negative effects on plants. On the other hand, plants have their own resistance mechanisms against toxic effects and for detoxifying heavy metal pollution. To study the effects of heavy metals on plants and mechanisms of resistance, one must select crop cultivars and/or plants for removing heavy metals from soil and water. More highly resistant plants can be selected especially for a remediation of the pollution site. The molecular mechanisms of resistance of plants to heavy metals should be studied further to develop the actual resistance of these plants to heavy metals. Understanding the bioavailability of heavy metals is advantageous for plant cultivation and phytoremediation. Decrease in the bioavailability to farmlands would reduce the accumulation of heavy metals in food. Alternatively, one could increase the bioavailability of plants to extract more heavy metals.

Prevalence of exposure of heavy metals and their impact on health consequences.

PubMed

Rehman, Kanwal; Fatima, Fiza; Waheed, Iqra; Akash, Muhammad Sajid Hamid

2018-01-01

Even in the current era of growing technology, the concentration of heavy metals present in drinking water is still not within the recommended limits as set by the regulatory authorities in different countries of the world. Drinking water contaminated with heavy metals namely; arsenic, cadmium, nickel, mercury, chromium, zinc, and lead is becoming a major health concern for public and health care professionals. Occupational exposure to heavy metals is known to occur by the utilization of these metals in various industrial processes and/or contents including color pigments and alloys. However, the predominant source resulting in measurable human exposure to heavy metals is the consumption of contaminated drinking water and the resulting health issues may include cardiovascular disorders, neuronal damage, renal injuries, and risk of cancer and diabetes. The general mechanism involved in heavy metal-induced toxicity is recognized to be the production of reactive oxygen species resulting oxidative damage and health related adverse effects. Thus utilization of heavy metal-contaminated water is resulting in high morbidity and mortality rates all over the world. Thereby, feeling the need to raise the concerns about contribution of different heavy metals in various health related issues, this article has discussed the global contamination of drinking water with heavy metals to assess the health hazards associated with consumption of heavy metal-contaminated water. A relationship between exposure limits and ultimate responses produced as well as the major organs affected have been reviewed. Acute and chronic poisoning symptoms and mechanisms responsible for such toxicities have also been discussed. © 2017 Wiley Periodicals, Inc.

Translocation and toxicity assessment of heavy metals from circulated fluidized-bed combustion of oil shale in Huadian, China.

PubMed

Luan, Jingde; Li, Aimin; Su, Tong; Li, Xuan

2009-07-30

Oil shale and fly ash collected from two thermal power plants located in Huadian, the northeast city of China were subjected to fraction distribution, translocation regularity and toxicity assessment to provide preliminary assessment of suitability for land application. By Tessier sequential extraction, the results showed that Ni, Cr, Pb and Zn were mostly bounded with iron-manganese and organic bound in oil shale, but Cu and Cd were mostly associated with iron-manganese bound and residue fraction. Through circulated fluidized-bed combustion, high concentration of heavy metals (Cu, Cd, Ni, Cr, Pb, and Zn) was found in iron-manganese bound and residue fraction in fly ash. There was accumulation of all studied metals except Ni and Cr in fly ash and translocation mass of metals were as follows: Pb>Zn>Cu>Cd during circulated fluidized-bed combustion. Fly ash was contaminated with Cd higher than the pollution concentration limits listed in GB15168-1995, China. This work demonstrated that it was unadvisable way to carry out landfill without any treatment. By means of STI model, toxicity assessment of heavy metals was carried out to show that there was notable increase in toxicity from oil shale to fly ash.

Atmospheric deposition exposes Qinling pandas to toxic pollutants.

PubMed

Chen, Yi-Ping; Zheng, Ying-Juan; Liu, Qiang; Song, Yi; An, Zhi-Sheng; Ma, Qing-Yi; Ellison, Aaron M

2017-03-01

The giant panda (Ailuropoda melanoleuca) is one of the most endangered animals in the world, and it is recognized worldwide as a symbol for conservation. A previous study showed that wild and captive pandas, especially those of the Qinling subspecies, were exposed to toxicants in their diet of bamboo; the ultimate origin of these toxicants is unknown. Here we show that atmospheric deposition is the most likely origin of heavy metals and persistent organic pollutants (POPs) in the diets of captive and wild Qinling pandas. Average atmospheric deposition was 199, 115, and 49 g·m -2 ·yr -1 in the center of Xi'an City, at China's Shaanxi Wild Animal Research Center (SWARC), and at Foping National Nature Reserve (FNNR), respectively. Atmospheric deposition of heavy metals (As, Cd, Cr, Pb, Hg, Co, Cu, Zn, Mn, and Ni) and POPs was highest at Xi'an City, intermediate at SWARC, and lowest at FNNR. Soil concentrations of the aforementioned heavy metals other than As and Zn also were significantly higher at SWARC than at FNNR. Efforts to conserve Qinling pandas may be compromised by air pollution attendant to China's economic development. Improvement of air quality and reductions of toxic emissions are urgently required to protect China's iconic species. © 2017 by the Ecological Society of America.

Ocean urea fertilization for carbon credits poses high ecological risks.

PubMed

Glibert, Patricia M; Azanza, Rhodora; Burford, Michele; Furuya, Ken; Abal, Eva; Al-Azri, Adnan; Al-Yamani, Faiza; Andersen, Per; Anderson, Donald M; Beardall, John; Berg, G Mine; Brand, Larry; Bronk, Deborah; Brookes, Justin; Burkholder, Joann M; Cembella, Allan; Cochlan, William P; Collier, Jackie L; Collos, Yves; Diaz, Robert; Doblin, Martina; Drennen, Thomas; Dyhrman, Sonya; Fukuyo, Yasuwo; Furnas, Miles; Galloway, James; Granéli, Edna; Ha, Dao Viet; Hallegraeff, Gustaaf; Harrison, John; Harrison, Paul J; Heil, Cynthia A; Heimann, Kirsten; Howarth, Robert; Jauzein, Cécile; Kana, Austin A; Kana, Todd M; Kim, Hakgyoon; Kudela, Raphael; Legrand, Catherine; Mallin, Michael; Mulholland, Margaret; Murray, Shauna; O'Neil, Judith; Pitcher, Grant; Qi, Yuzao; Rabalais, Nancy; Raine, Robin; Seitzinger, Sybil; Salomon, Paulo S; Solomon, Caroline; Stoecker, Diane K; Usup, Gires; Wilson, Joanne; Yin, Kedong; Zhou, Mingjiang; Zhu, Mingyuan

2008-06-01

The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many grow well on urea and some even increase their toxicity when grown on urea. Many toxic dinoflagellates form cysts which can settle to the sediment and germinate in subsequent years, forming new blooms even without further fertilization. If large-scale blooms do occur, it is likely that they will contribute to hypoxia in the bottom waters upon decomposition. Lastly, urea production requires fossil fuel usage, further limiting the potential for net carbon sequestration. The environmental and economic impacts are potentially great and need to be rigorously assessed.

Ocean Urea Fertilization for Carbon Credits Poses High Ecological Risks

PubMed Central

Glibert, Patricia M.; Azanza, Rhodora; Burford, Michele; Furuya, Ken; Abal, Eva; Al-Azri, Adnan; Al-Yamani, Faiza; Andersen, Per; Beardall, John; Berg, G. Mine; Brand, Larry; Bronk, Deborah; Brookes, Justin; Burkholder, JoAnn M.; Cembella, Allan; Cochlan, William P.; Collier, Jackie; Collos, Yves; Diaz, Robert; Doblin, Martina; Drennen, Thomas; Dyhrman, Sonya; Fukuyo, Yasuwo; Furnas, Miles; Galloway, James; Granéli, Edna; Ha, Dao Viet; Hallegraeff, Gustaaf; Harrison, John; Harrison, Paul J.; Heil, Cynthia A.; Heimann, Kirsten; Howarth, Robert; Jauzein, Cécile; Kana, Austin A.; Kana, Todd M.; Kim, Hakgyoon; Kudela, Raphael; Legrand, Catherine; Mallin, Michael; Mulholland, Margaret; Murray, Shauna; O’Neil, Judith; Pitcher, Grant; Qi, Yuzao; Rabalais, Nancy; Raine, Robin; Seitzinger, Sybil; Solomon, Caroline; Stoecker, Diane K.; Usup, Gires; Wilson, Joanne; Yin, Kedong; Zhou, Mingjiang; Zhu, Mingyuan

2017-01-01

The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many grow well on urea and some even increase their toxicity when grown on urea. Many toxic dinoflagellates form cysts which can settle to the sediment and germinate in subsequent years, forming new blooms even without further fertilization. If large-scale blooms do occur, it is likely that they will contribute to hypoxia in the bottom waters upon decomposition. Lastly, urea production requires fossil fuel usage, further limiting the potential for net carbon sequestration. The environmental and economic impacts are potentially great and need to be rigorously assessed. PMID:18439628

Naval Law Review (Volume 59, 2010)

DTIC Science & Technology

2010-01-01

also that Yokosuka Naval Station in Japan was so heavily tainted with soil contaminated with PCBs and heavy metals that it could not be legally...147 However, after decades of dumping heavy metals and other hazardous materials, substantial contamination was left behind.148 The United States...subcommittee on defense, that heavy metals , untreated chemicals, and toxic waste pollution were discharged into the ground at Clark); see also

Comparative Investigation of Copper Tolerance and Identification of Putative Tolerance Related Genes in Tardigrades

PubMed Central

Hygum, Thomas L.; Fobian, Dannie; Kamilari, Maria; Jørgensen, Aslak; Schiøtt, Morten; Grosell, Martin; Møbjerg, Nadja

2017-01-01

Tardigrades are microscopic aquatic animals renowned for their tolerance toward extreme environmental conditions. The current study is the first to investigate their tolerance toward heavy metals and we present a novel tardigrade toxicant tolerance assay based on activity assessments as a measure of survival. Specifically, we compare tolerance toward copper in four species representing different evolutionary lineages, habitats and adaptation strategies, i.e., a marine heterotardigrade, Echiniscoides sigismundi, a limno-terrestrial heterotardigrade, Echiniscus testudo, a limno-terrestrial eutardigrade, Ramazzottius oberhaeuseri, and a marine eutardigrade, Halobiotus crispae. The latter was sampled at a time of year, when the population is predominantly represented by aberrant P1 cysts, while the other species were in normal active states prior to exposure. Based on volume measurements and a general relation between body mass and copper tolerance, expected tardigrade EC50 values were estimated at 0.5–2 μg l−1. Following 24 h of exposure, tolerance was high with no apparent link to lineage or habitat. EC50s (95% CI), 24 h after exposure, were estimated at 178 (168–186) and 310 (295–328) μg l−1, respectively, for E. sigismundi and R. oberhaeuseri, whereas E. testudo and H. crispae were less affected. Highest tolerance was observed in H. crispae with a mean ± s.e.m. activity of 77 ± 2% (n = 3) 24 h after removal from ~3 mg l−1 copper, suggesting that tardigrade cysts have increased tolerance toward toxicants. In order to identify putative tolerance related genes, an E. sigismundi transcriptome was searched for key enzymes involved in osmoregulation, antioxidant defense and copper metabolism. We found high expression of Na/K ATPase and carbonic anhydrase, known targets for copper. Our transcriptome, furthermore, revealed high expression of antioxidant enzymes, copper transporters, ATOX1, and a Cu-ATPase. In summary, our results indicate that tardigrades express well-known key osmoregulatory enzymes, supporting the hypothesis that copper inhibits sodium turnover as demonstrated for other aquatic organisms. Tardigrades, nevertheless, have high tolerance toward the toxicant, which is likely linked to high expression of antioxidant enzymes and an ability to enter dormant states. Tardigrades, furthermore, seem to have a well-developed battery of cuproproteins involved in copper homeostasis, providing basis for active copper sequestering and excretion. PMID:28293195

Comparative Investigation of Copper Tolerance and Identification of Putative Tolerance Related Genes in Tardigrades.

PubMed

Hygum, Thomas L; Fobian, Dannie; Kamilari, Maria; Jørgensen, Aslak; Schiøtt, Morten; Grosell, Martin; Møbjerg, Nadja

2017-01-01

Tardigrades are microscopic aquatic animals renowned for their tolerance toward extreme environmental conditions. The current study is the first to investigate their tolerance toward heavy metals and we present a novel tardigrade toxicant tolerance assay based on activity assessments as a measure of survival. Specifically, we compare tolerance toward copper in four species representing different evolutionary lineages, habitats and adaptation strategies, i.e., a marine heterotardigrade, Echiniscoides sigismundi , a limno-terrestrial heterotardigrade, Echiniscus testudo , a limno-terrestrial eutardigrade, Ramazzottius oberhaeuseri , and a marine eutardigrade, Halobiotus crispae . The latter was sampled at a time of year, when the population is predominantly represented by aberrant P1 cysts, while the other species were in normal active states prior to exposure. Based on volume measurements and a general relation between body mass and copper tolerance, expected tardigrade EC50 values were estimated at 0.5-2 μg l -1 . Following 24 h of exposure, tolerance was high with no apparent link to lineage or habitat. EC50s (95% CI), 24 h after exposure, were estimated at 178 (168-186) and 310 (295-328) μg l -1 , respectively, for E. sigismundi and R. oberhaeuseri , whereas E. testudo and H. crispae were less affected. Highest tolerance was observed in H. crispae with a mean ± s.e.m . activity of 77 ± 2% ( n = 3) 24 h after removal from ~3 mg l -1 copper, suggesting that tardigrade cysts have increased tolerance toward toxicants. In order to identify putative tolerance related genes, an E. sigismundi transcriptome was searched for key enzymes involved in osmoregulation, antioxidant defense and copper metabolism. We found high expression of Na/K ATPase and carbonic anhydrase, known targets for copper. Our transcriptome, furthermore, revealed high expression of antioxidant enzymes, copper transporters, ATOX1, and a Cu-ATPase. In summary, our results indicate that tardigrades express well-known key osmoregulatory enzymes, supporting the hypothesis that copper inhibits sodium turnover as demonstrated for other aquatic organisms. Tardigrades, nevertheless, have high tolerance toward the toxicant, which is likely linked to high expression of antioxidant enzymes and an ability to enter dormant states. Tardigrades, furthermore, seem to have a well-developed battery of cuproproteins involved in copper homeostasis, providing basis for active copper sequestering and excretion.

Chromium toxicity to nitrifying bacteria: implications to wastewater treatment

EPA Science Inventory

Chromium, a heavy metal that enters wastewater treatment plants (WWTPs) through industrial discharges, can be toxic to microorganisms carrying out important processes within biological wastewater treatment systems. The effect of Cr(III) and Cr(VI) on ammonia dependent specific ox...

Fluorescent sensor based models for the detection of environmentally-related toxic heavy metals.

PubMed

Rasheed, Tahir; Bilal, Muhammad; Nabeel, Faran; Iqbal, Hafiz M N; Li, Chuanlong; Zhou, Yongfeng

2018-02-15

The quest for industrial and biotechnological revolution has been contributed in increasing environmental contamination issues, worldwide. The controlled or uncontrolled release of hazardous pollutants from various industrial sectors is one of the key problems facing humanity. Among them, adverse influences of lead, cadmium, and mercury on human health are well known to cause many disorders like reproductive, neurological, endocrine system, and cardiovascular, etc. Besides their presence at lower concentrations, most of these toxic heavy metals are posing noteworthy toxicological concerns. In this context, notable efforts from various regulatory authorities, the increase in the concentration of these toxic heavy metals in the environment is of serious concern, so real-time monitoring is urgently required. This necessitates the exploration for novel and efficient probes for recognition of these toxic agents. Among various methodologies adopted for tailoring such probes, generally the methodologies, in which changes associated with spectral properties, are preferred for the deceptive ease in the recognition process. Accordingly, a promising modality has emerged in the form of radiometric and colorimetric monitoring of these toxic agents. Herein, we review fluorescent sensor based models and their potentialities to address the detection fate of hazardous pollutants for a cleaner environment. Second, recent advances regarding small molecule and rhodamine-based fluorescent sensors, radiometric and colorimetric probes are discussed. The information is also given on the photoinduced electron transfer (PET) mechanism, chelation enhancement fluorescence (CHEF) effect and spirocyclic ring opening mechanism. Copyright © 2017 Elsevier B.V. All rights reserved.

Surface modified mesostructured iron oxyhydroxide: synthesis, ecotoxicity, and application.

PubMed

Choi, Jae-Woo; Mahendran, Basuvaraj; Chung, Seung-Gun; Kim, Song-Bae; Lee, Sang-Hyup

2014-12-01

Mesoporous iron oxide, particularly amine-functionalized FeO(x) and FeO(x), was investigated for the removal of toxic heavy metal anions of arsenic and chromium from an aqueous solution. As a control experiment for these toxic compounds, adsorption tests were also performed on Fe3O4 as their counterpart bulk chemical. The mesostructures were confirmed by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and transmission electron microscopy (TEM). In addition, we prepared stock suspensions of meso-FeO(x), amine-functionalized meso-FeO(x) and Fe3O4 particles, and compared their acute toxicity against Daphnia magna. The 24 h-EC50 values of the amine-functionalized meso-FeO(x), meso-FeO(x) and Fe particle suspensions used in this study were 1682, 2549 and 95 mg/L, respectively. Organism toxicity caused by spills of adsorbents can be negated when the amine-functionalized meso-FeO(x), up to 1500 mg/L, is used as the adsorbent for heavy metal treatment. The adsorption of arsenic and chromium by the three adsorbents were examined, and different adsorption models were used to describe the equilibrium and kinetic data. The amine-functionalized meso-FeO(x) adsorbent was found to give the maximum adsorption capacities for arsenic and chromium (33.51 and 25.05 mg/g, respectively). This research gives promising results for the application of modified meso-FeO(x) as an adsorbent of toxic heavy metal anions from aqueous solutions.

Occupational Neurotoxic Diseases in Taiwan

PubMed Central

Liu, Chi-Hung; Huang, Chu-Yun

2012-01-01

Occupational neurotoxic diseases have become increasingly common in Taiwan due to industrialization. Over the past 40 years, Taiwan has transformed from an agricultural society to an industrial society. The most common neurotoxic diseases also changed from organophosphate poisoning to heavy metal intoxication, and then to organic solvent and semiconductor agent poisoning. The nervous system is particularly vulnerable to toxic agents because of its high metabolic rate. Neurological manifestations may be transient or permanent, and may range from cognitive dysfunction, cerebellar ataxia, Parkinsonism, sensorimotor neuropathy and autonomic dysfunction to neuromuscular junction disorders. This study attempts to provide a review of the major outbreaks of occupational neurotoxins from 1968 to 2012. A total of 16 occupational neurotoxins, including organophosphates, toxic gases, heavy metals, organic solvents, and other toxic chemicals, were reviewed. Peer-reviewed articles related to the electrophysiology, neuroimaging, treatment and long-term follow up of these neurotoxic diseases were also obtained. The heavy metals involved consisted of lead, manganese, organic tin, mercury, arsenic, and thallium. The organic solvents included n-hexane, toluene, mixed solvents and carbon disulfide. Toxic gases such as carbon monoxide, and hydrogen sulfide were also included, along with toxic chemicals including polychlorinated biphenyls, tetramethylammonium hydroxide, organophosphates, and dimethylamine borane. In addition we attempted to correlate these events to the timeline of industrial development in Taiwan. By researching this topic, the hope is that it may help other developing countries to improve industrial hygiene and promote occupational safety and health care during the process of industrialization. PMID:23251841

Heavy Metals and Related Trace Elements.

ERIC Educational Resources Information Center

Leland, Harry V.; And Others

1978-01-01

Presents a literature review of heavy metals and related trace elements in the environment, covering publications of 1976-77. This review includes: (1) trace treatment in natural water and in sediments; and (2) bioaccumulation and toxicity of trace elements. A list of 466 references is presented. (HM)

Unknown risk: co-exposure to lead and other heavy metals among children living in small-scale mining communities in Zamfara State, Nigeria.

PubMed

Bartrem, Casey; Tirima, Simba; von Lindern, Ian; von Braun, Margrit; Worrell, Mary Claire; Mohammad Anka, Shehu; Abdullahi, Aishat; Moller, Gregory

2014-08-01

The lead poisoning crisis in Zamfara State, Northern Nigeria has been called the worst such case in modern history and it presents unique challenges for risk assessment and management of co-exposure to multiple heavy metals. More than 400 children have died in Zamfara as a result of ongoing lead intoxication since early in 2010. A review of the common toxic endpoints of the major heavy metals advances analysis of co-exposures and their common pathologies. Environmental contamination in Bagega village, examined by X-ray fluorescence of soils, includes lead, mercury, cadmium, arsenic and manganese. Co-exposure risk is explored by scoring common toxic endpoints and hazard indices to calculate a common pathology hazard risk ranking of Pb > As > Hg > Cd > Mn. Zamfara presents an extreme picture of both lead and multiple heavy metal mortality and morbidity, but similar situations have become increasingly prevalent worldwide.

Heavy Metals Effect on Cyanobacteria Synechocystis aquatilis Study Using Absorption, Fluorescence, Flow Cytometry, and Photothermal Measurements

NASA Astrophysics Data System (ADS)

Dudkowiak, A.; Olejarz, B.; Łukasiewicz, J.; Banaszek, J.; Sikora, J.; Wiktorowicz, K.

2011-04-01

The toxic effect of six heavy metals on cyanobacteria Synechocystis aquatilis was studied by absorption, fluorescence, flow cytometry, and photothermal measurements. This study indicates that at the concentration used, the cyanobacteria are more sensitive to silver, copper, and mercury than to cadmium, lead, and zinc metals. Disregarding the decrease in the yields of the related radiative processes caused by photochemical processes and/or damage to phycobilisomes, no changes were detected in the efficiency of thermal deactivation processes within a few microseconds, which can indicate the lack of disturbances in the photosynthetic light reaction and the lack of damage to the photosystem caused by the heavy metal ions in the concentrations used. The results demonstrate that the relative values of fluorescence yield as well as promptly generated heat calculated for the metal-affected and unaffected (reference) bacteria are sensitive indicators of environmental pollution with heavy metal ions, whereas the complementary methods proposed could be used as a noninvasive and fast procedure for in vivo assessment of their toxicity.

[Limiting factors of waste land revegetation in indigenous zinc smelting areas of western Guizhou].

PubMed

Lin, Wen-Jie; Xiao, Tang-Fu; Ao, Zi-Qiang; Xing, Jun; Ma, Huan-Cheng; Hu, Ting-Xing

2007-03-01

With indigenous zinc smelting waste residue, contaminated soil and background soil as test substrates, a pot experiment was conducted to study the growth characteristics of Lolium perenne and Trifolium pretense on these substrates. The results showed that the major limiting factors of waste land revegetation in indigenous zinc smelting areas of western Guizhou were the salt-alkali stress and the lower contents of organic matter, total N, available N and total K. The heavy metals in waste residue had a high concentration, but their available forms only occupied a small proportion, with low toxicity to plant but having potential harmful risk. Contaminated soil had lower concentrations of heavy metals than waste residue, but its contained heavy metals were more in available form. The constraints of revegetation on contaminated soil were the toxicity of heavy metals and the low contents of available P and K. Mixing contaminated soil with zinc smelting waste residue could be one of the effective approaches for the substrate amendment in indigenous zinc smelting areas.

Carbonized waste for the cut-down of environmental pollution with heavy metals

NASA Astrophysics Data System (ADS)

Gmucová, K.; Morvová, M.; Havránek, E.; Kliman, J.; Košinár, I.; Kunecová, D.; Malakhov, A. I.; Anisimov, Yu. S.; Morva, I.; Siváček, I.; Sýkorová, M.; Šatka, A.

2011-07-01

Nowadays, an increasing concern about the treatment and disposal of waters contaminated by toxic heavy metals is noticed. The toxic pollutants must be removed from the sewage water which then is fed back into the materials cycle. Any candidate technology should result in reusable by-products. With this in mind, the aim of the present study is to test a low cost procedure for utilization of the carbonized waste, a product of PET (polyethylene terephthalate) bottles pyrolysis on sand bedding, for this purpose. Both the water present in PET bottles waste and combustion exhaust probably contribute to the conversion of carbon char to activated carbon directly within the pyrolysis oven. Preliminary results, obtained for several heavy metal ions under laboratory conditions are presented and discussed. Adsorption of heavy metals on the carbonized PET waste is tested by both the electrochemical methods and X-ray fluorescence spectrometry. A simple desorption procedure for the regeneration of prepared active carbon is proposed.

Role of microgel formation in scavenging of chromophoric dissolved organic matter and heavy metals in a river-sea system.

PubMed

Shiu, Ruei-Feng; Lee, Chon-Lin

2017-04-15

We use riverine and marine dissolved organic carbon (DOC) polymers to examine their aggregation behavior, and to evaluate the roles of microgel formation in scavenging of chromophoric dissolved organic matter (CDOM) and heavy metals in a river-sea system. Our results indicate that riverine and marine microgels did not exhibit very much difference in size and self-assembly curve; however, the assembly effectiveness ([microgel]/DOC) of marine samples was much higher than riverine. Instead of concentration of DOC, other factors such as types and sources of DOC polymers may control the microgel abundance in aquatic environments. After filtering water samples (microgels removed), the CDOM and selected metals (Cu, Ni, Mn) in the filtrate were quantified. CDOM and metals were concurrently removed to an extent via DOC polymer re-aggregation, which also suggested that the microgels had sequestering capability in CDOM and metals. This finding provides an alternative route for CDOM and heavy metals removal from the water column. As such the process of re-aggregation into microgels should then be considered besides traditional phase partitioning in the assessment of the ecological risk and fate of hazardous materials. Copyright © 2017 Elsevier B.V. All rights reserved.

Design and Synthesis of Self-Assembled Monolayers on Mesoporous Supports (SAMMS): The Importance of Ligand Posture in Functional Nanomaterials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fryxell, Glen E.; Mattigod, Shas V.; Lin, Yuehe

2007-07-01

Water, and water quality, are issues of critical importance to the future of humankind. The Earth’s water supplies have been contaminated by a wide variety of industrial, military and natural sources. The need exists for an efficient separation technology to remove heavy metal and radionuclide contamination from water. Surfactant templated synthesis of mesoporous ceramics provides a versatile foundation upon which to build high efficiency environmental sorbents. These nanoporous ceramics condense a huge amount of surface area into a very small volume. These mesoporous architectures can be subsequently functionalized through molecular self-assembly. These functional mesoporous materials offer significant capabilities in termsmore » of removal of heavy metals and radionuclides from a variety of liquid media, including groundwater, contaminated oils and contaminated chemical weapons. They are highly efficient sorbents, whose rigid, open pore structure allows for rapid, efficient sorption kinetics. Their interfacial chemistry can be fine-tuned to selectively sequester a specific target species, such as heavy metals, tetrahedral oxometallate anions and radionuclides. This manuscript provides a review of the design, synthesis and performance of the sorbent materials. The role that ligand posture plays in the chemistry of these interfacial ligand fields is discussed.« less

Selenite reduction by the obligate aerobic bacterium Comamonas testosteroni S44 isolated from a metal-contaminated soil

PubMed Central

2014-01-01

Background Selenium (Se) is an essential trace element in most organisms but has to be carefully handled since there is a thin line between beneficial and toxic concentrations. Many bacteria have the ability to reduce selenite (Se(IV)) and (or) selenate (Se(VI)) to red elemental selenium that is less toxic. Results A strictly aerobic bacterium, Comamonas testosteroni S44, previously isolated from metal(loid)-contaminated soil in southern China, reduced Se(IV) to red selenium nanoparticles (SeNPs) with sizes ranging from 100 to 200 nm. Both energy dispersive X-ray Spectroscopy (EDX or EDS) and EDS Elemental Mapping showed no element Se and SeNPs were produced inside cells whereas Se(IV) was reduced to red-colored selenium in the cytoplasmic fraction in presence of NADPH. Tungstate inhibited Se(VI) but not Se(IV) reduction, indicating the Se(IV)-reducing determinant does not contain molybdenum as co-factor. Strain S44 was resistant to multiple heavy and transition metal(loid)s such as Se(IV), As(III), Cu(II), and Cd(II) with minimal inhibitory concentrations (MIC) of 100 mM, 20 mM, 4 mM, and 0.5 mM, respectively. Disruption of iscR encoding a transcriptional regulator negatively impacted cellular growth and subsequent resistance to multiple heavy metal(loid)s. Conclusions C. testosteroni S44 could be very useful for bioremediation in heavy metal(loid) polluted soils due to the ability to both reduce toxic Se(VI) and Se(IV) to non-toxic Se (0) under aerobic conditions and to tolerate multiple heavy and transition metals. IscR appears to be an activator to regulate genes involved in resistance to heavy or transition metal(loid)s but not for genes responsible for Se(IV) reduction. PMID:25098921

Potential resource and toxicity impacts from metals in waste electronic devices.

PubMed

Woo, Seung H; Lee, Dae Sung; Lim, Seong-Rin

2016-04-01

As a result of the continuous release of new electronic devices, existing electronic devices are quickly made obsolete and rapidly become electronic waste (e-waste). Because e-waste contains a variety of metals, information about those metals with the potential for substantial environmental impact should be provided to manufacturers, recyclers, and disposers to proactively reduce this impact. This study assesses the resource and toxicity (i.e., cancer, noncancer, and ecotoxicity) potentials of various heavy metals commonly found in e-waste from laptop computers, liquid-crystal display (LCD) monitors, LCD TVs, plasma TVs, color cathode ray tube (CRT) TVs, and cell phones and then evaluates such potentials using life cycle impact-based methods. Resource potentials derive primarily from Cu, Sb, Ag, and Pb. Toxicity potentials derive primarily from Pb, Ni, and Hg for cancer toxicity; from Pb, Hg, Zn, and As for noncancer toxicity; and from Cu, Pb, Hg, and Zn for ecotoxicity. Therefore, managing these heavy metals should be a high priority in the design, recycling, and disposal stages of electronic devices. © 2015 SETAC.

Heavy Metals Toxicity and the Environment

PubMed Central

Tchounwou, Paul B; Yedjou, Clement G; Patlolla, Anita K; Sutton, Dwayne J

2013-01-01

Heavy metals are naturally occurring elements that have a high atomic weight and a density at least 5 times greater than that of water. Their multiple industrial, domestic, agricultural, medical and technological applications have led to their wide distribution in the environment; raising concerns over their potential effects on human health and the environment. Their toxicity depends on several factors including the dose, route of exposure, and chemical species, as well as the age, gender, genetics, and nutritional status of exposed individuals. Because of their high degree of toxicity, arsenic, cadmium, chromium, lead, and mercury rank among the priority metals that are of public health significance. These metallic elements are considered systemic toxicants that are known to induce multiple organ damage, even at lower levels of exposure. They are also classified as human carcinogens (known or probable) according to the U.S. Environmental Protection Agency, and the International Agency for Research on Cancer. This review provides an analysis of their environmental occurrence, production and use, potential for human exposure, and molecular mechanisms of toxicity, genotoxicity, and carcinogenicity. PMID:22945569

The test ability of fish Tawes to leachate garbage dump (TPA) Benowo

NASA Astrophysics Data System (ADS)

Juliardi AR, N. R.; Wiyanti, R. I.

2018-01-01

Leachate is a liquid from waste containing elements of dissolved and suspended elements. Garbage collected at the landfill site contains organic, inorganic and heavy metal substances. If the rains will produce leachate with mineral content, organic and heavy metals. When the condition or leachate flow in let to the soil surface can cause negative effects to the surrounding environment including for humans. Toxicity test it was conducted to determine the level of leachate toxicity of the test animals living in surface water located around of the “TPA Benowo”. In this study using Tawes fish with length between 4-6 cm. In this toxicity test is done in 2 stages, namely: range finding test, the search for this range is obtained 0% concentrations (as control) 0,3%; 0,6%; 0,9%; 0,12% and 0,15%. The next stage of toxicity acute test, at this stage of toxicity concentration do smaller again that is: 0,18%; 0,36%; 0,54%; 0,72% and 0,9%. The results obtained LC50 value of 0,385%, while eyes, brown stomach skin.

Supercritical Fluid Extraction of Toxic Heavy Metals and Uranium from Acidic Solutions with Sulfur-Containing Organophosphorus Reagents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Yuehe; Liu, Chongxuan; Wu, Hong

2003-03-02

The feasibility of using sulfur-containing organophosphorus reagents for the chelation-supercritical fluid extraction (SFE) of toxic heavy metals and uranium from acidic media was investigated. The SFE experiments were conducted in a specially-designed flow-through liquid extractor. Effective extraction of the metal ions from various acidic media was demonstrated. The effect of ligand concentration in supercritical CO{sub 2} on the kinetics of metal extraction was studied. A simplified model is used to describe the extraction kinetics and the good agreement of experimental data with the equilibrium-based model is achieved.

Leachate composition and toxicity assessment: an integrated approach correlating physicochemical parameters and toxicity of leachates from MSW landfill in Delhi.

PubMed

Gupta, Anshu; Paulraj, R

2017-07-01

Landfills are considered the most widely practiced method for disposal of municipal solid waste (MSW) and 95% of the total MSW collected worldwide is disposed of in landfills. Leachate produced from MSW landfills may contain a number of pollutants and pose a potential environmental risk for surface as well as ground water. In the present study, chemical analysis and toxicity assessment of landfill leachate have been carried out. Leachate samples were collected from Ghazipur landfill site, New Delhi. Leachates were characterized by measuring the concentration of heavy metals (Pb, Cu, Cr and Ni), 5-day biochemical oxygen demand (BOD 5 ), chemical oxygen demand (COD), pH, electrical conductivity and SO 4 2 -. For toxicity testing of leachate, Triticum aestivum (wheat) was selected and testing was done in a time- and dose-dependent manner using the crude leachate. Median lethal concentration after 24 and 48 h of exposure was observed. The main objective of this study was to evaluate toxicity of MSW landfill leachate and establish a possible correlation between the measured physicochemical parameters and resultant toxicity. Statistical analysis showed that toxicity was dependent on the concentration of heavy metals (Pb, Cu), conductivity, and organic matter (COD and BOD5).

A CONTROLLED BIOASSAY SYSTEM FOR MEASURING TOXICITY OF HEAVY METALS

EPA Science Inventory

Biological availability of metal micronutrients and metal toxicity are believed to be dependent on metal oxidation state, complexation, and solubility as well as the physicochemical characteristics of the aqueous phase. Basic design criteria for fish bioassays which are capable o...

Biological characterization of lead-enhanced exopolysaccharide produced by a lead resistant Enterobacter cloacae strain P2B.

PubMed

Naik, Milind Mohan; Pandey, Anju; Dubey, Santosh Kumar

2012-09-01

A lead resistant bacterial strain isolated from effluent of lead battery manufacturing company of Goa, India has been identified as Enterobacter cloacae strain P2B based on morphological, biochemical characters, FAME profile and 16S rDNA sequence data. This bacterial strain could resist lead nitrate up to 1.6 mM. Significant increase in exopolysaccharide (EPS) production was observed as the production increased from 28 to 108 mg/L dry weight when exposed to 1.6 mM lead nitrate in Tris buffered minimal medium. Fourier-transformed infrared spectroscopy of this EPS revealed presence of several functional groups involved in metal binding viz. carboxyl, hydroxyl and amide groups along with glucuronic acid. Gas chromatography coupled with mass spectrometry analysis of alditol-acetate derivatives of acid hydrolysed EPS produced in presence of 1.6 mM lead nitrate demonstrated presence of several neutral sugars such as rhamnose, arabinose, xylose, mannose, galactose and glucose, which contribute to lead binding hydroxyl groups. Scanning electron microscope coupled with energy dispersive X-ray spectrometric analysis of this lead resistant strain exposed to 1.6 mM lead nitrate interestingly revealed mucous EPS surrounding bacterial cells which sequestered 17 % lead (as weight %) extracellularly and protected the bacterial cells from toxic effects of lead. This lead resistant strain also showed multidrug resistance. Thus these results significantly contribute to better understanding of structure, function and environmental application of lead-enhanced EPSs produced by bacteria. This lead-enhanced biopolymer can play a very important role in bioremediation of several heavy metals including lead.

Manganese toxicity upon overexposure

PubMed Central

Crossgrove, Janelle; Zheng, Wei

2014-01-01

Manganese (Mn) is a required element and a metabolic byproduct of the contrast agent mangafodipir trisodium (MnDPDP). The Mn released from MnDPDP is initially sequestered by the liver for first-pass elimination, which allows an enhanced contrast for diagnostic imaging. The administration of intravenous Mn impacts its homeostatic balance in the human body and can lead to toxicity. Human Mn deficiency has been reported in patients on parenteral nutrition and in micronutrient studies. Mn toxicity has been reported through occupational (e.g. welder) and dietary overexposure and is evidenced primarily in the central nervous system, although lung, cardiac, liver, reproductive and fetal toxicity have been noted. Mn neurotoxicity results from an accumulation of the metal in brain tissue and results in a progressive disorder of the extrapyramidal system which is similar to Parkinson's disease. In order for Mn to distribute from blood into brain tissue, it must cross either the blood–brain barrier (BBB) or the blood–cerebrospinal fluid barrier (BCB). Brain import, with no evidence of export, would lead to brain Mn accumulation and neurotoxicity. The mechanism for the neurodegenerative damage specific to select brain regions is not clearly understood. Disturbances in iron homeostasis and the valence state of Mn have been implicated as key factors in contributing to Mn toxicity. Chelation therapy with EDTA and supplementation with levodopa are the current treatment options, which are mildly and transiently efficacious. In conclusion, repeated administration of Mn, or compounds that readily release Mn, may increase the risk of Mn-induced toxicity. PMID:15617053

Comparison of heavy metal toxicity in continuous flow and batch reactors

NASA Astrophysics Data System (ADS)

Sengor, S. S.; Gikas, P.; Moberly, J. G.; Peyton, B. M.; Ginn, T. R.

2009-12-01

The presence of heavy metals may significantly affect microbial growth. In many cases, small amounts of particular heavy metals may stimulate microbial growth; however, larger quantities may result in microbial growth reduction. Environmental parameters, such as growth pattern may alter the critical heavy metal concentration, above which microbial growth stimulation turns to growth inhibition. Thus, it is important to quantify the effects of heavy metals on microbial activity for understanding natural or manmade biological reactors, either in situ or ex situ. Here we compare the toxicity of Zn and Cu on Arthrobacter sp., a heavy metal tolerant microorganism, under continuous flow versus batch reactor operations. Batch and continuous growth tests of Arthrobacter sp. were carried out at various individual and combined concentrations of Zn and Cu. Biomass concentration (OD) was measured for both the batch and continuous reactors, whereas ATP, oxygen uptake rates and substrate concentrations were additionally measured for the continuous system. Results indicated that Cu was more toxic than Zn under all conditions for both systems. In batch reactors, all tested Zn concentrations up to 150 uM showed a stimulatory effect on microbial growth. However, in the case of mixed Zn and Cu exposures, the presence of Zn either eliminated (at the 50 uM level both Zn and Cu) or reduced by ~25% (at the 100 and 150 uM levels both Zn and Cu) the Cu-induced inhibition. In the continuous system, only one test involved combined Cu (40uM) and Zn (125uM) and this test showed similar results to the 40uM Cu continuous test, i.e., no reduction in inhibition. The specific ATP concentration, i.e., ATP/OD, results for the continuous reactor showed an apparent recovery for both Cu-treated populations, although neither the OD nor glucose data showed any recovery. This may reflect that the individual microorganisms that survived after the addition of heavy metals, kept maintaining the usual ATP levels, as before metal addition. The last may imply a short of adaptation by some microorganisms to the presence of heavy metals. Overall, the batch reactor tests underestimated significantly the heavy metal inhibition, as compared to the continuous flow reactors. Therefore, the results of batch reactor tests should be used with some caution when heavy metal inhibition is to be interpreted for continuous flow natural environmental systems, such as rivers or wetlands.

Environmental toxicants and autism spectrum disorders: a systematic review

PubMed Central

Rossignol, D A; Genuis, S J; Frye, R E

2014-01-01

Although the involvement of genetic abnormalities in autism spectrum disorders (ASD) is well-accepted, recent studies point to an equal contribution by environmental factors, particularly environmental toxicants. However, these toxicant-related studies in ASD have not been systematically reviewed to date. Therefore, we compiled publications investigating potential associations between environmental toxicants and ASD and arranged these publications into the following three categories: (a) studies examining estimated toxicant exposures in the environment during the preconceptional, gestational and early childhood periods; (b) studies investigating biomarkers of toxicants; and (c) studies examining potential genetic susceptibilities to toxicants. A literature search of nine electronic scientific databases through November 2013 was performed. In the first category examining ASD risk and estimated toxicant exposures in the environment, the majority of studies (34/37; 92%) reported an association. Most of these studies were retrospective case–control, ecological or prospective cohort studies, although a few had weaker study designs (for example, case reports or series). Toxicants implicated in ASD included pesticides, phthalates, polychlorinated biphenyls (PCBs), solvents, toxic waste sites, air pollutants and heavy metals, with the strongest evidence found for air pollutants and pesticides. Gestational exposure to methylmercury (through fish exposure, one study) and childhood exposure to pollutants in water supplies (two studies) were not found to be associated with ASD risk. In the second category of studies investigating biomarkers of toxicants and ASD, a large number was dedicated to examining heavy metals. Such studies demonstrated mixed findings, with only 19 of 40 (47%) case–control studies reporting higher concentrations of heavy metals in blood, urine, hair, brain or teeth of children with ASD compared with controls. Other biomarker studies reported that solvent, phthalate and pesticide levels were associated with ASD, whereas PCB studies were mixed. Seven studies reported a relationship between autism severity and heavy metal biomarkers, suggesting evidence of a dose–effect relationship. Overall, the evidence linking biomarkers of toxicants with ASD (the second category) was weaker compared with the evidence associating estimated exposures to toxicants in the environment and ASD risk (the first category) because many of the biomarker studies contained small sample sizes and the relationships between biomarkers and ASD were inconsistent across studies. Regarding the third category of studies investigating potential genetic susceptibilities to toxicants, 10 unique studies examined polymorphisms in genes associated with increased susceptibilities to toxicants, with 8 studies reporting that such polymorphisms were more common in ASD individuals (or their mothers, 1 study) compared with controls (one study examined multiple polymorphisms). Genes implicated in these studies included paraoxonase (PON1, three of five studies), glutathione S-transferase (GSTM1 and GSTP1, three of four studies), δ-aminolevulinic acid dehydratase (one study), SLC11A3 (one study) and the metal regulatory transcription factor 1 (one of two studies). Notably, many of the reviewed studies had significant limitations, including lack of replication, limited sample sizes, retrospective design, recall and publication biases, inadequate matching of cases and controls, and the use of nonstandard tools to diagnose ASD. The findings of this review suggest that the etiology of ASD may involve, at least in a subset of children, complex interactions between genetic factors and certain environmental toxicants that may act synergistically or in parallel during critical periods of neurodevelopment, in a manner that increases the likelihood of developing ASD. Because of the limitations of many of the reviewed studies, additional high-quality epidemiological studies concerning environmental toxicants and ASD are warranted to confirm and clarify many of these findings. PMID:24518398

Process Design and Cost Estimating Algorithms for the Computer Assisted Procedure for Design and Evaluation of Wastewater Treatment Systems (CAPDET).

DTIC Science & Technology

1982-01-01

mg/l. 2.1.9.1.3.3 Nitrogen, I Mg 1. 2.1.9.1.3.4 Phosphorus (total and soluble), ag/l. 2.1.9.1.3.5 Oils and greases, mg/l. 2.1.9.1.3.6 Heavy metals , mg...greases, mg/I. 2.1.10.1.3.6 Heavy metals , m/l. 2.1.10.1.3.7 Toxic or special characteristics (e.g., phenols), mg/I. 2.1.10.1.3.8 Temperature, OF or °C...1 mg/l. 2.1.11.1.3.4 Phosphorus (total and soluble), mg/I. 2.1.11.1.3.5 Oils and greases, mgl. 2.1.11.1.3.6 Heavy metals , mg/l. 2.1.11.1.3.7 Toxic or

Toxic heavy metals in human blood in relation to certain food and environmental samples in Kerala, South India.

PubMed

Jose, Anitha; Ray, Joseph George

2018-03-01

Toxic heavy metals such as arsenic (As), lead (Pb), and mercury (Hg) are systemic toxicants that are hazardous to human health. However, as these elements are increasing in the environment due to fast urbanization, industrialization, and chemicalized agricultural activities, accumulation of the same in human body anywhere in the world is quite interesting to global assessment of environment quality. In this connection, random examination of blood samples of human population in Kerala, South India, was carried out to assess the threat of heavy metal contamination to humans in this part of the globe, especially in relation to the amount of such metals in food and other environmental samples. Except pure vegetarians, people of Kerala consume rice as the staple food with a lot of fish. Therefore, the amount of these three heavy metals in drinking water, fish, rice, and paddy soils was done. Heavy metals in the blood were examined in relation to age, gender, and dietary habits such as frequency of fish eating or vegetarianism. Influence of dental amalgam fillings on blood mercury levels was also analyzed. Quantitative assessment of metals in samples was done by inductively coupled plasma-mass spectrometry (ICP-MS). The levels of arsenic, lead, and mercury were found well below the reference values, though diet seemed to pull them up as the amount of metals in blood showed significant differences between vegetarians and non-vegetarians. Evidence to the influence of dental amalgam fillings on blood mercury levels could not be established with the present samples.

Different strategies of cadmium detoxification in the submerged macrophyte Ceratophyllum demersum L.

PubMed

Andresen, Elisa; Mattusch, Jürgen; Wellenreuther, Gerd; Thomas, George; Arroyo Abad, Uriel; Küpper, Hendrik

2013-10-01

The heavy metal cadmium (Cd) is highly toxic to plants. To understand the mechanisms of tolerance and resistance to Cd, we treated the rootless, submerged macrophyte Ceratophyllum demersum L. with sub-micromolar concentrations of Cd under environmentally relevant conditions. X-ray fluorescence measurements revealed changing distribution patterns of Cd and Zn at non-toxic (0.2 nM, 2 nM), moderately toxic (20 nM) and highly toxic (200 nM) levels of Cd. Increasing Cd concentrations led to enhanced sequestration of Cd into non-photosynthetic tissues like epidermis and vein. At toxic Cd concentrations, Zn was redistributed and mainly found in the vein. Cd treatment induced the synthesis of phytochelatins (PCs) in the plants, with a threshold of induction already at 20 nM Cd for PC3. In comparison, in plants treated with Cu, elevated PC levels were detected only at the highest concentrations (100-200 nM Cu). Our results show that also non-accumulators like C. demersum store toxic metals in tissues where the heavy metal interferes least with metabolic pathways, but remaining toxicity interferes with micronutrient distribution. Furthermore, we found that the induction of phytochelatins is not proportional to metal concentration, but has a distinct threshold, specific for each PC species. Finally we could show that 20 nM Cd, which was previously regarded as non-toxic to most plants, already induces detoxifying mechanisms.

Effect of dissolved humic acid on the Pb bioavailability in soil solution and its consequence on ecological risk.

PubMed

An, Jinsung; Jho, Eun Hea; Nam, Kyoungphile

2015-04-09

Current risk characterization in ecological risk assessment does not consider bioavailability of heavy metals, which highly depends on physicochemical properties of environmental media. This study was set to investigate the effect of humic acid (HA), used as a surrogate of organic matter, on Pb toxicity and the subsequent effect on risk characterization in ecological risk assessment. Pb toxicity was assessed using Microtox(®) in the presence and absence of two different forms of HA, particulate HA (pHA) and dissolved HA (dHA). With increasing contact time, the EC10 values increased (i.e., the toxic effects decreased) and the dissolved Pb concentrations of the filtrates decreased. The high correlation (R = 0.88, p < 0.001) between toxic effects determined using both the mixture and its filtrate as exposure media leads us to conclude that the Pb toxicity highly depends on the soluble fraction. Also, reduced Pb toxicity with increasing dHA concentrations, probably due to formation of Pb-dHA complexes, indicated that Pb toxicity largely comes from free Pb ions. Overall, this study shows the effect of HA on metal toxicity alleviation, and emphasizes the need for incorporating the bioavailable heavy metal concentrations in environmental media as a point of exposure in ecological risk assessment. Copyright © 2015 Elsevier B.V. All rights reserved.

Stormwater Effects on Heavy Metal Sequestration in a Bioretention System in Culver City, California

NASA Astrophysics Data System (ADS)

Yousavich, D. J.; Ellis, A. S.; Dorsey, J.; Johnston, K.

2017-12-01

Rain Gardens, also referred to as bioretention or biofilters, are often used to capture or filter urban runoff before it drains into surface or groundwater systems. The Culver City Rain Garden (CCRG) is one such system that is designed to capture and filter runoff from approximately 11 acres of mixed-use commercial and industrial land before it enters Ballona Creek. The EPA has designated Ballona Creek as an impaired waterway and established Total Maximum Daily Loads for heavy metals. Previous research has utilized sequential extractions to establish trends in heavy metal sequestration for Cu, Pb, and Zn in bioretention media. The aim of this project is to evaluate if there is a difference in heavy metal sequestration between dry and wetted bioretention media. To characterize the stormwater at the site, influent and surface water were collected and analyzed for sulfate and heavy metals 3 times during the 2016-2017 storm season. Two soil cores from the CCRG were acquired in the summer of 2017 to analyze soil metal sequestration trends. They will be subjected to different wetting conditions, sectioned into discrete depths, and digested with an established sequential extraction technique. Surface water in the CCRG shows average Dissolved Oxygen during wet conditions of 2.92 mg/L and average pH of 6.1 indicating reducing conditions near the surface and the possible protonation of adsorption sites during wet weather conditions. Influent metal data indicate average dissolved iron levels near 1 ppm and influent Cu, Pb, and Zn levels near 0.05, 0.01, and 0.5 ppm respectively. This coupled with average surface water sulfate levels near 3 ppm indicates the potential for iron oxide and sulfide mineral formation depending on redox conditions. The sequential extraction results will elucidate whether heavy metals are adsorbed or are being sequestered in mineral formation. These results will allow for the inclusion of heavy metal sequestration trends in the design of further bioretention projects and maintenance of current sites.

A review of phytoremediation technology: heavy metals uptake by plants

NASA Astrophysics Data System (ADS)

Sumiahadi, A.; Acar, R.

2018-03-01

Heavy metal is one of the serious environmental pollutions for now days as impact of industrial development in several countries. Heavy metals give toxic effects on human health and cause several serious diseases. Several techniques have been using for removing heavy metal contaminants from the environmental but these techniques have limitations such as high cost, long time, logistical problems and mechanical complexity. Phytoremediation can be used as an alternative solution for heavy metal remediation process because of its advantages as a cost-effective, efficient, environment- and eco-friendly technology based on the use of metal-accumulating plants. According to previous studies, several plants have a high potential as heavy metals bioaccumulator and can be used for phytoremediation process of heavy metals.

Heavy metal in sediments of Ziya River in northern China: distribution, potential risks, and source apportionment.

PubMed

Zhu, Xiaolei; Shan, Baoqing; Tang, Wenzhong

2016-12-01

The concentration partitioning between the sediment particle and the interstitial water phase plays an important role in controlling the toxicity of heavy metals in aquatic systems. The aim of this study was to assess the sediment quality in a polluted area of the Ziya River, Northern China. The contamination potential and bioavailability of six metals were determined from the concentrations of total metals and the bioavailable fractions. The results showed that the concentrations of Cr, Cu, Ni, Zn, and Pb exceeded the probable effect concentration at several sites. The high geoaccumulation indices showed that the sediments were seriously contaminated by Cd. The ratio of acid-volatile sulfide (AVS) to simultaneously extracted metal (SEM) was higher than 1, which indicated that the availability of metals in sediments was low. The risk assessment of interstitial waters confirmed that there was little chance of release of metals associated with acid-volatile sulfide into the water column. Values of the interstitial water criteria toxicity unit indicated that none of the concentrations of the studied metals exceeded the corresponding water quality thresholds of the US Environmental Protection Agency. Positive matrix factorization showed that the major sources of metals were related to anthropogenic activities. Further, if assessments are based on total heavy metal concentrations, the toxicity of heavy metals in sediment may be overestimated.

Changes in growth, biochemical components, and antioxidant activity in aquatic plant Wolffia arrhiza (Lemnaceae) exposed to cadmium and lead.

PubMed

Piotrowska, Alicja; Bajguz, Andrzej; Godlewska-Zyłkiewicz, Beata; Zambrzycka, Elzbieta

2010-04-01

The present study investigated the biochemical response of aquatic plant Wolffia arrhiza (Lemnaceae) treated with lead (Pb) and cadmium (Cd) at a range of concentrations from 1 to 1000 microM. W. arrhiza has been identified as good scavenger of heavy metals from aqueous solution. Pb and Cd accumulation was found to be increased in a concentration- and duration-dependent manner. However, the highest biosorption of heavy metals was found in plants exposed to low levels (10 microM) of Cd and Pb in the nutrient medium. In observing the response to heavy-metal stress, we noted inhibited plant growth and decreased photosynthetic pigments, monosaccharides, and proteins. In addition, Cd was found to be more toxic to plants than Pb. Heavy metals also induced oxidative damage as evidenced by increased lipid peroxidation and hydrogen peroxide levels. In contrast, the deleterious effects resulting from the cellular oxidative state can be alleviated by enzymatic (catalase, ascorbate peroxidase, nicotinamide dinucleotide [NADH] peroxidase) and nonenzymatic (ascorbate, glutathione) antioxidant mechanisms activated in W. arrhiza plants exposed to Cd and Pb, especially at 10 microM. These results suggest that W. arrhiza is a promising bioindicator of heavy-metal toxicity.

Survey of toxicity and carcinogenity of mineral deposits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Furst, A.; Harding-Barlow, I.

1981-11-03

The toxicities and biogeochemical cycles of arsenic, cadmium, chromium, lead and nickel are reviewed in some detail, and other trace elements briefly mentioned. These heavy metals are used as a framework within which the problem of low-level radioactive waste disposal can be compared. (ACR)

EPA Requires ASARCO to Cut Toxic Emissions at 103-Year-Old Arizona Copper Smelter

EPA Pesticide Factsheets

U.S. DOJ and EPA announce settlement with ASARCO requiring the company to spend $150 million to install new equipment and pollution control technology to reduce emissions of toxic heavy metals at a large smelter located in Hayden, Ariz.

The toxic Doppelganger: on the ionic and molecular mimicry of cadmium.

PubMed

Chmielowska-Bąk, Jagna; Izbiańska, Karolina; Deckert, Joanna

2013-01-01

Cadmium is a toxic heavy metal which can cause numerous alterations in cell functioning. Exposure to cadmium leads to generation of reactive oxygen species, disorders in membrane structure and functioning, inhibition of respiration, disturbances in ion homeostasis, perturbations in cell division, and initiation of apoptosis and necrosis. This heavy metal is considered a carcinogen by the Agency for Toxic Substances and Disease Registry. At least some of the described toxic effects could result from the ability of cadmium to mimic other divalent ions and alert signal transduction networks. This review describes the role of cadmium mimicry in its uptake, reactive oxygen species generation, alterations in calmodulin, Wnt/β-catenin and estrogen signaling pathways, and modulation of neurotransmission. The last section is dedicated to the single known case of a favorable function performed by cadmium mimicry: marine diatoms, which live in zinc deficient conditions, utilize cadmium as a cofactor in carbonic anhydrase - so far the only described cadmium enzyme.

Use of absorption mechanisms to decrease heavy metal mobility.

DOT National Transportation Integrated Search

2014-02-01

The objective of this project is to reduce the toxic heavy metal leaching from coal fly ash so that the fly ash may be used for road : surface or related applications. Trona (trisodium hydrogendicarbonate dihydrate, Na3HCO3CO32H2O) is injected into...

DEVELOPMENT OF BIO-BASED MOLECULAR TECHNOLOGIES FOR REMOVAL AND REAL-TIME MONITORING OF TOXIC METALS

EPA Science Inventory

Transformation of heavy-metal related genes from a hyper-accumulator to a high-biomass species is expected to promote a zinc hyper-accumulating phenotype in the normally non-hyper-accumulating poplar. Coupling fluorescence with heavy metal proteins is anticipated to allow ...

MECHANISMS OF HEAVY METAL REMOVAL FROM ACID MINE DRAINAGE USING CHITIN

EPA Science Inventory

Acid Mine Drainage (AMD) emanating from inactive or active mine sites contains elevated levels of toxic heavy metals, which can have an adverse impact to the surrounding environment. The major pathway involved in generation of AMD is weathering of pyritic mineral ores, where in s...

[Biological activity of selenorganic compounds at heavy metal salts intoxication].

PubMed

Rusetskaya, N Y; Borodulin, V B

2015-01-01

Possible mechanisms of the antitoxic action of organoselenium compounds in heavy metal poisoning have been considered. Heavy metal toxicity associated with intensification of free radical oxidation, suppression of the antioxidant system, damage to macromolecules, mitochondria and the genetic material can cause apoptotic cell death or the development of carcinogenesis. Organic selenium compounds are effective antioxidants during heavy metal poisoning; they exhibit higher bioavailability in mammals than inorganic ones and they are able to activate antioxidant defense, bind heavy metal ions and reactive oxygen species formed during metal-induced oxidative stress. One of promising organoselenium compounds is diacetophenonyl selenide (DAPS-25), which is characterized by antioxidant and antitoxic activity, under conditions including heavy metal intoxication.

Alleviation of heavy metal toxicity and phytostimulation of Brassica campestris L. by endophytic Mucor sp. MHR-7.

PubMed

Zahoor, Mahwish; Irshad, Muhammad; Rahman, Hazir; Qasim, Muhammad; Afridi, Sahib Gul; Qadir, Muhammad; Hussain, Anwar

2017-08-01

Heavy metal (HM) pollution is of great concern in countries like Pakistan where a huge proportion of human population is exposed to it. These toxic metals are making their way from water bodies to soil where it not only interferes with plant growth and development but also initiates serious health issues in human consuming the produce of such soils. Bioremediation is one of the most viable and efficient solution for the problem. Purpose of the current study was to isolate endophytic fungi from plants grown on HM contaminated soil and screen them for their ability to tolerate multiple HM including chromium (Cr 6+ ), manganese (Mn 2+ ), cobalt (Co 2+ ), copper (Cu 2+ ) and zinc (Zn 2+ ). Out of 27 isolated endophytes, only one strain (MHR-7) was selected for multiple heavy metals tolerance. The strain was identified as Mucor sp. by 18S and 28S ribosomal RNA internal transcribed spacer (ITS) 1 and 4 sequence homology. The strain effectively tolerated up to 900µgmL -1 of these heavy metals showing no remarkable effect on its growth. The adverse effect of the heavy metals, measured as reduction of the fungal growth increased with increasing concentration of the metals. The strain was able to remove 60-87% of heavy metals from broth culture when supplied with 300µgmL -1 of these metals. A trend of decline in bioremediation potential of the strain was observed with increasing amount of metals. The strain removed metals by biotransformation and/or accumulation of heavy metal in its hyphae. Application of Mucor sp. MHR-7 locked down HM in tis mycelium thereby making them less available to plant root reducing HM uptake and toxicity in mustard. Besides its bioremediation potential, the strain was also able to produce IAA, ACC deaminase and solubilize phosphate making it excellent phytostimulant fungus. It is concluded that MHR-7 is an excellent candidate for use as biofertilizer in fields affected with heavy metals. Copyright © 2017 Elsevier Inc. All rights reserved.

Occurrence, spatial distribution, sources, and risks of polychlorinated biphenyls and heavy metals in surface sediments from a large eutrophic Chinese lake (Lake Chaohu).

PubMed

He, Wei; Bai, Ze-Lin; Liu, Wen-Xiu; Kong, Xiang-Zhen; Yang, Bin; Yang, Chen; Jørgensen, Sven Erik; Xu, Fu-Liu

2016-06-01

Surface sediment from large and eutrophic Lake Chaohu was investigated to determine the occurrence, spatial distribution, sources, and risks of polychlorinated biphenyls (PCBs) and heavy metals in one of the five biggest freshwater lakes in China. Total concentration of PCBs (Σ34PCBs) in Lake Chaohu was 672 pg g(-1) dry weight (dw), with a range of 7 to 3999 pg g(-1) dw, which was lower than other water bodies worldwide. The majority of heavy metals were detected at all sampling locations, except for Sr, B, and In. Concentrations of Al, Fe, Ca, Mn, Sr, Co, Zn, Cd, Pb, and Hg were similar to that reported for other lakes globally. Concentrations of K, Mg, Na, Li, Ga, and Ag were greater than the average, whereas those of Cr, Ni, and Cu were lower. Cluster analysis (CA) and positive matrix factorization (PMF) yielded accordant results for the source apportionment of PCBs. The technical PCBs and microbial degradation accounted for 34.2 % and 65.8 % of total PCBs using PMF, and PMF revealed that natural and anthropogenic sources of heavy metals accounted for 38.1 % and 61.8 %, respectively. CA indicated that some toxic heavy metals (e.g., Cd, In, Tl, and Hg) were associated with Ca-Na-Mg minerals rather than Fe-Mn minerals. The uncorrelated results between organic matter revealed by pyrolysis technology and heavy metals might be caused by the existence of competitive adsorption between organic matter and minerals. PCBs and heavy metals were coupling discharge without organochlorine pesticides (OCPs), but with polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs). No sediment sample exceeded the toxic threshold for dioxin-like PCBs (dl-PCBs) set at 20 pg toxicity equivalency quantity (TEQ) g(-1), (max dl-PCBs, 10.9 pg TEQ g(-1)). However, concentrations of Ag, Cd, and Hg were at levels of environmental concern. The sediment in the drinking water source area (DWSA) was threatened by heavy metals from other areas, and some fundamental solutions were proposed to protect the DWSA.

Characteristics of and sorption to biochars derived from waste material

NASA Astrophysics Data System (ADS)

Sun, Huichao; Kah, Melanie; Sigmund, Gabriel; Hofmann, Thilo

2015-04-01

Biochars can exhibit a high sorption potential towards heavy metals and organic contaminants in various environmental matrices (e.g., water, soil). They have therefore been proposed for environmental remediation purposes to sequester contaminants. To date, most studies have focused on the physicochemical and sorption properties of mineral phases poor biochars, which are typically produced from plant residues. Only little knowledge is available for biochars derived from human and animal waste material, which are typically characterized by high mineral contents (e.g., sewage sludge, manure). Using human and animal waste as source material to produce biochars would support the development of attractive combined strategies for waste management and remediation. The potential impact of mineral phases on the physicochemical and sorption properties of biochars requires further studies so that the potential as sorbent material can be evaluated. With this purpose, different source material biochars were produced at 200°C, 350°C and 500°C, to yield a series of biochars representing a range of mineral content. The derived biochars from wood shavings (<1% ash), sewage sludge (50-70% ash) and pig manure (30-60% ash), as well as a commercial biochar derived from grain husks (40% ash), were extensively characterized (e.g., element composition, surface area, porosity, Fourier transform infrared spectroscopy). The contents of potentially toxic elements (i.e., heavy metals and polycyclic aromatic hydrocarbons) of all materials were within the guidelines values proposed by the International Biochar Initiative, indicating their suitability for environmental application. Single point sorption coefficients for the model sorbate pyrene were measured to investigate the effect of mineral content, feedstock, pyrolysis temperature, particle size fractions and acid demineralization on sorption behavior. Overall, sorption of pyrene was strong for all materials (4 < Log Kd < 6.5 L/kg). Sorption generally increased with increasing pyrolysis temperature but there was no effect of particle size on sorption affinity. For mineral phase rich biochars, sorption generally increased after acid demineralization. When considering all materials together, the sorbent aromaticity (hydrogen-carbon ratio) was the most important factor controlling sorption of pyrene. Overall, the study demonstrates that biochars derived from human and animal waste material and exhibiting high mineral contents have potential for remediation applications.

Gulf War Illnesses: Understanding of Health Effects From Depleted Uranium Evolving But Safety Training Needed

DTIC Science & Technology

2000-03-01

against enemy munitions. Depleted uranium is a low- level radioactive heavy metal , and concerns have surfaced about whether exposure to it could be a...radioactive heavy metal , the potential for health effects are twofold: effects from radiation and effects from chemical toxicity. Two recent expert...depleted uranium safety training. Background Depleted uranium (DU), a low-level radioactive heavy metal , is a by- product of the process used to

Risk assessment of toxic heavy metals in the abandoned metal mine areas, Korea

NASA Astrophysics Data System (ADS)

Lee, J. S.; Chon, H. T.

2003-04-01

The purpose of this study is to assess the risk of adverse health effects on human exposure to toxic heavy metals influenced by past mining activities. Environmental geochemical survey was undertaken in the abandoned metal mine areas (Dongil Au-Ag-Cu-Zn mine, Okdong Cu-Pb-Zn mine, Myungbong Au-Ag mine). After appropriate sample preparation, tailings, soils, crop plants and groundwaters were analyzed for As, Cd, Cu, Pb and Zn by ICP-AES and ICP-MS. Health risk assessment of toxic heavy metals has been performed with chemical analytical data for environmental media. Arsenic and other heavy metals are highly elevated in the tailings from the Dongil mine (8,720 As mg/kg, 5.9 Cd mg/kg, 3,610 Cu mg/kg, 5,850 Pb mg/kg, 630 Zn mg/kg), but heavy metals except As from the Okdong mine (72 As mg/kg, 53.6 Cd mg/kg, 910 Cu mg/kg, 1,590 Pb mg/kg, 5,720 Zn mg/kg) and only As from the Myungbong mine (5,810 As mg/kg). These significant concentrations can impact on soils and waters around the tailing files. Also, elevated levels of As, Cd, Cu, Pb and Zn are found in agricultural soils from these mine areas. Risk assessment modeling is subdivided into main four stages, i.e. hazard identification, exposure assessment, toxicity (dose-response) assessment and risk characterization. In order to assess exposure it is necessary to calculate the average daily dose (ADD) of contaminant via the three identified pathways (soil, groundwater and food (rice grain) pathways). In dose-response assessment for non-carcinogens, reference doses (RfD) are calculated and that for carcinogens, slope factors (SF) are obtained by US-EPA IRIS database. In risk characterization, the results of toxicity assessment and exposure assessment are integrated to arrive at quantitative estimates of cancer risks and hazard quotients. Toxic (non-cancer) risks are indicated in terms of a hazard quotient (H.Q.) and this risk exists for H.Q.>1. The H.Q. values for only As from the Dongil and Myungbong mine areas are 2.1 and 1.35, respectively. Therefore, toxic risk for As exists via exposure (ingestion) of contaminated soil, groundwater and rice grain in these mine areas, more than 1.0. The cancer risks for As in groundwater used by drinking water in the Dongil, the Okdong and the Myungbong mine areas are 9E-4, 1E-4 and 6E-4, respectively. These risk levels in the Dongil and the Myungbong mine exceed in the range of 1 in 10,000 to 1 in 1,000,000 required the remedial actions.

Trace Metals in Soot and PM2.5 from Heavy-Fuel-Oil Combustion in a Marine Engine

PubMed Central

2018-01-01

Heavy fuel oil (HFO) particulate matter (PM) emitted by marine engines is known to contain toxic heavy metals, including vanadium (V) and nickel (Ni). The toxicity of such metals will depend on the their chemical state, size distribution, and mixing state. Using online soot-particle aerosol mass spectrometry (SP-AMS), we quantified the mass of five metals (V, Ni, Fe, Na, and Ba) in HFO-PM soot particles produced by a marine diesel research engine. The in-soot metal concentrations were compared to in-PM2.5 measurements by inductively coupled plasma-optical emission spectroscopy (ICP-OES). We found that <3% of total PM2.5 metals was associated with soot particles, which may still be sufficient to influence in-cylinder soot burnout rates. Since these metals were most likely present as oxides, whereas studies on lower-temperature boilers report a predominance of sulfates, this result implies that the toxicity of HFO PM depends on its combustion conditions. Finally, we observed a 4-to-25-fold enhancement in the ratio V:Ni in soot particles versus PM2.5, indicating an enrichment of V in soot due to its lower nucleation/condensation temperature. As this enrichment mechanism is not dependent on soot formation, V is expected to be generally enriched within smaller HFO-PM particles from marine engines, enhancing its toxicity. PMID:29688717

Effect of Microbial inoculation in combating the aluminium toxicity effect on growth of Zea mays.

PubMed

Arora, P; Singh, G; Tiwari, A

2017-07-31

The present study is aimed at improving the aluminium tolerance in maize crop employing the potential of microbial inoculants in conferring resistance to these toxicities via production of certain chelating compounds like siderophores, exopolysachharides and organic acids. Acid soils have now-a-days become one of the key factors for limiting growth of many agriculturally important crops. Aluminium  is one of the major elements present in acid soils and is mainly responsible for toxicity in the soil. This aluminium is rapidly soluble in soil water and hence absorbed by plant roots under conditions where soil pH is below 5. This toxicity leads to severe root growth inhibition, thereby limiting the production of maize crops. It was observed that use of microbial inoculums can be helpful in elimination of these toxic compounds and prevent the inhibition of root growth . It was found that the soils contaminated with aluminium toxicity decreased the root length of maize plant significantly by 65% but Bacillus and Burkholderia inoculation increased this root length significantly by 1.4- folds and 2- folds respectively thereby combating the effect of aluminium toxicity. Aluminium concentration was found maximum in roots of plants which were grown under aluminium stress condition. But this aluminium accumulation decreased ̴ 2-folds when Burkholderia was used as seed inoculants under aluminium stress conditions. Also, at 60mM aluminium accumulation, phosphorus solubilisation in roots was found to be increased upto 30% on Burkholderia inoculation. However, Bacillus inoculation didn't show any significant difference in either of the case. Thus, the inoculation of seeds with Burkholderia isolates could prove to be a boon in sequestering aluminium toxicity in Zea mays.

A Drosophila model for toxicogenomics: Genetic variation in susceptibility to heavy metal exposure

PubMed Central

Luoma, Sarah E.; St. Armour, Genevieve E.; Thakkar, Esha

2017-01-01

The genetic factors that give rise to variation in susceptibility to environmental toxins remain largely unexplored. Studies on genetic variation in susceptibility to environmental toxins are challenging in human populations, due to the variety of clinical symptoms and difficulty in determining which symptoms causally result from toxic exposure; uncontrolled environments, often with exposure to multiple toxicants; and difficulty in relating phenotypic effect size to toxic dose, especially when symptoms become manifest with a substantial time lag. Drosophila melanogaster is a powerful model that enables genome-wide studies for the identification of allelic variants that contribute to variation in susceptibility to environmental toxins, since the genetic background, environmental rearing conditions and toxic exposure can be precisely controlled. Here, we used extreme QTL mapping in an outbred population derived from the D. melanogaster Genetic Reference Panel to identify alleles associated with resistance to lead and/or cadmium, two ubiquitous environmental toxins that present serious health risks. We identified single nucleotide polymorphisms (SNPs) associated with variation in resistance to both heavy metals as well as SNPs associated with resistance specific to each of them. The effects of these SNPs were largely sex-specific. We applied mutational and RNAi analyses to 33 candidate genes and functionally validated 28 of them. We constructed networks of candidate genes as blueprints for orthologous networks of human genes. The latter not only provided functional contexts for known human targets of heavy metal toxicity, but also implicated novel candidate susceptibility genes. These studies validate Drosophila as a translational toxicogenomics gene discovery system. PMID:28732062

Comparative In Vitro Toxicity Evaluation of Heavy Metals (Lead, Cadmium, Arsenic, and Methylmercury) on HT-22 Hippocampal Cell Line.

PubMed

Karri, Venkatanaidu; Kumar, Vikas; Ramos, David; Oliveira, Eliandre; Schuhmacher, Marta

2018-07-01

Heavy metals are considered some of the most toxic environmental pollutants. Exposure to heavy metals including lead (Pb), cadmium (Cd), arsenic (As), and methyl mercury (MeHg) has long been known to cause damage to human health. Many recent studies have supported the hippocampus as the major target for these four metals for inflicting cognitive dysfunction. In the present study, we proposed hippocampal relevant in vitro toxicity of Pb, Cd, As, and MeHg in HT-22 cell line. This study reports, initially, cytotoxic effects in acute, subchronic, chronic exposures. We further investigated the mechanistic potency of DNA damage and apoptosis damage with the observed cytotoxicity. The genotoxicity and apoptosis were measured by using the comet assay, annexin-V FTIC / propidium iodide (PI) assay, respectively. The results of cytotoxicity assay clearly demonstrated significant concentration and time-dependent effects on HT-22 cell line. The genotoxic and apoptosis effects also concentration-dependent fashion with respect to their potency in the range of IC 10 -IC 30, maximal level of damage observed in MeHg. In conclusion, the obtained result suggests concentration and potency-dependent response; the maximal level of toxicity was observed in MeHg. These novel findings support that Pb, Cd, As, and MeHg induce cytotoxic, genotoxic, and apoptotic effects on HT-22 cells in potency-dependent manner; MeHg> As> Cd> Pb. Therefore, the toxicity of Pb, Cd, As, and MeHg could be useful for knowing the common underlying molecular mechanism, and also for estimating the mixture impacts on HT-22 cell line.

Contamination level, distribution and health risk assessment of heavy and toxic metallic and metalloid elements in a cultivated mushroom Pleurotus florida (Mont.) singer.

PubMed

Khani, Rouhollah; Moudi, Maryam; Khojeh, Vahid

2017-02-01

There are great concentrations of toxic metallic and metalloid elements such as lead, arsenic, mercury, cadmium or silver in many species of mushrooms comparative to other fruits and vegetables. In this study, contamination with heavy and toxic metallic and metalloid elements in the cultivated mushroom of (Pleurotus florida (Mont.) Singer) is investigated. P. florida was cultivated on different substrates; wheat straw (as blank), wheat straw + pine cone, wheat straw + soybean straw and wheat straw + urea and the effects of these substrates on contamination levels of Mn, Fe, Cu, Zn, As, Cd, and Pb were analyzed. The results showed that the concentrations of essential elements (Mn, Fe, Cu, and Zn) in the target mushroom are at the typical levels. The estimated daily intakes of studied metallic and metalloid elements were below their oral reference dosage mentioned by the international regulatory bodies. Health risk index (HRI) was calculated to evaluate the consumer's health risk assessment from the metal intake that contaminated in the cultivated mushroom of P. florida on the different nutrient sources. In this study, the individual HRIs were less than 1, which indicates insignificant potential health risk associated with the consumption of target mushroom from the studied substrates. Based on the HRIs values among the toxic metallic and metalloid elements, As in the target mushroom in the substrate of the wheat straw + pine cone is the main sources of risk, and it may cause severe health problems. Thus, this study suggests that the concentrations of heavy and toxic elements should be periodically monitored in cultivated mushrooms.

Biodiesel and Cold Temperature Effects on Speciated Mobile Source Air Toxics from Modern Diesel Trucks

EPA Science Inventory

Speciated volatile organic compounds (VOCs) with a particular focus on mobile source air toxics (MSATs) were measured in diesel exhaust from three heavy-duty trucks equipped with modern aftertreatment technologies. Emissions testing was conducted on a temperature controlled chass...

Biodiesel and Cold Temperature Effect on Speciated Mobile Source Air Toxics from Modern Diesel Trucks

EPA Science Inventory

Speciated volatile organic compounds (VOCs) with a particular focus on mobile source air toxics (MSATs) were measured in diesel exhaust from three heavy-duty trucks equipped with modern aftertreatment technologies. Emissions testing was conducted on a temperature controlled chass...

Mercury-pollution induction of intracellular lipid accumulation and lysosomal compartment amplification in the benthic foraminifer Ammonia parkinsoniana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frontalini, Fabrizio; Curzi, Davide; Cesarini, Erica

In this study, heavy metals such as mercury (Hg) pose a significant health hazard through bioaccumulation and biomagnification. By penetrating cell membranes, heavy metal ions may lead to pathological conditions. Here we examined the responses of Ammonia parkinsoniana, a benthic foraminiferan, to different concentrations of Hg in the artificial sea water. Confocal images of untreated and treated specimens using fluorescent probes (Nile Red and Acridine Orange) provided an opportunity for visualizing the intracellular lipid accumulation and acidic compartment regulation. With increased Hg over time, we observed an increased number of lipid droplets, which may have acted as a detoxifying organellemore » where Hg is sequestered and biologically inactivated. Further, Hg seems to promote the proliferation of lysosomes both in terms of number and dimension that, at the highest level of Hg, resulted in cell death. We report, for the first time, the presence of Hg within the foraminiferal cell: at the basal part of pores, in the organic linings of the foramen/septa, and as cytoplasmic accumulations.« less

Mercury-pollution induction of intracellular lipid accumulation and lysosomal compartment amplification in the benthic foraminifer Ammonia parkinsoniana

DOE PAGES

Frontalini, Fabrizio; Curzi, Davide; Cesarini, Erica; ...

2016-09-07

In this study, heavy metals such as mercury (Hg) pose a significant health hazard through bioaccumulation and biomagnification. By penetrating cell membranes, heavy metal ions may lead to pathological conditions. Here we examined the responses of Ammonia parkinsoniana, a benthic foraminiferan, to different concentrations of Hg in the artificial sea water. Confocal images of untreated and treated specimens using fluorescent probes (Nile Red and Acridine Orange) provided an opportunity for visualizing the intracellular lipid accumulation and acidic compartment regulation. With increased Hg over time, we observed an increased number of lipid droplets, which may have acted as a detoxifying organellemore » where Hg is sequestered and biologically inactivated. Further, Hg seems to promote the proliferation of lysosomes both in terms of number and dimension that, at the highest level of Hg, resulted in cell death. We report, for the first time, the presence of Hg within the foraminiferal cell: at the basal part of pores, in the organic linings of the foramen/septa, and as cytoplasmic accumulations.« less

Pollution control and metal resource recovery for low grade automobile shredder residue: a mechanism, bioavailability and risk assessment.

PubMed

Singh, Jiwan; Lee, Byeong-Kyu

2015-04-01

Automobile shredder residue (ASR) is considered as hazardous waste in Japan and European countries due to presence of heavy metals. This study was carried on the extraction characteristics of heavy metals (Mn, Fe, Ni, and Cr) from automobile shredder residue (ASR). The effects of pH, temperature, particle size, and liquid/solid ratio (L/S) on the extraction of heavy metals were investigated. The recovery rate of Mn, Fe, Ni, and Cr increased with increasing extraction temperature and L/S ratio. The lowest pH 2, the highest L/S ratio, and the smallest particle size showed the highest recovery of heavy metals from ASR. The highest recovery rates were in the following order: Mn > Ni > Cr > Fe. Reduction of mobility factor for the heavy metals was observed in all the size fractions after the recovery. The results of the kinetic analysis for various experimental conditions supported that the reaction rate of the recovery process followed a second order reaction model (R(2) ⩾ 0.95). The high availability of water-soluble fractions of Mn, Fe, Ni, and Cr from the low grade ASR could be potential hazards to the environment. Bioavailability and toxicity risk of heavy metals reduced significantly with pH 2 of distilled water. However, water is a cost-effective extracting agent for the recovery of heavy metals and it could be useful for reducing the toxicity of ASR. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Systematic Review of Heavy Metals of Anthropogenic Origin in Environmental Media and Biota in the Context of Gold Mining in Ghana

PubMed Central

Armah, Frederick Ato; Quansah, Reginald; Luginaah, Isaac

2014-01-01

Heavy metal accumulation in the food chain is an issue of global concern because it eventually leads to toxic effects on humans through the water we drink, contaminated soils, crops, and animals. Reports of toxicant levels in environmental media (air, water, and soil) and biota in Ghana were sought in SCOPUS, PubMed, MEDLINE, and EMBASE. Of 1004 bibliographic records identified, 54 studies were included in evidence synthesis. A disproportionately large number of papers (about 80%) focused exclusively on environmental media. Papers focusing on biomonitoring and human health were relatively few. Studies reported a high degree of spatial variability for the concentrations of 8 metals in groundwater. Generally, heavy metal concentrations in soil reported by the studies reviewed were higher than metal concentrations in riverine sediments. Urine and hair were the most common biological markers of heavy metal exposure used by the studies reviewed unlike nails, which were sparingly used. By and large, published results on the levels of heavy metals in goldmine and non-mine workers yielded contradictory results. Mostly, concentrations of heavy metals reported by the studies reviewed for nails were higher than for hair. A high degree of variability in the heavy metal concentrations in human subjects in the studies reviewed is likely due to heterogeneity in physiological states, excretion profiles, and body burdens of individuals. These, in turn, may be a product of genetic polymorphisms influencing detoxification efficiency. PMID:27351015

Mass burden and estimated flux of heavy metals in Pakistan coast: sedimentary pollution and eco-toxicological concerns.

PubMed

Ali, Usman; Malik, Riffat Naseem; Syed, Jabir Hussain; Mehmood, Ch Tahir; Sánchez-García, Laura; Khalid, Azeem; Chaudhry, Muhammad Jamshed Iqbal

2015-03-01

Heavy-metal contamination in coastal areas poses a serious threat to aquatic life and public health due to their high toxicity and bio-accumulation potential. In the present study, levels of different heavy metals (Cu, Cd, Cr, Ni, Co, Pb, Zn, and Mn), their spatial distribution, geochemical status, and enrichment indices (Cu, Cd, Cr, Ni, Co, Pb, Zn) were investigated in the sediment samples from 18 coastal sites of Pakistan. The analyses of coastal sediments indicated the presence of heavy metals in order such as Cr > Zn > Cu > Pb > Ni > Mn > Co > Cd. Geo-accumulation index (I geo), enrichment factor (EF), and contamination factor (CF) showed diverse range in heavy-metal enrichment site by site. Pollution load index (PLI) has shown that average pollution load along the entire coastal belt was not significant. Based on the mean effect range medium quotient, coastal sediments of Pakistan had 21% probability of toxicity. The estimated sedimentary load of selected heavy metals was recorded in the range of 0.3-44.7 g/cm(2)/year, while the depositional flux was in the range of 0.07-43.5 t/year. Heavy-metal inventories of 9.8 × 10(2)-3.8 × 10(5) t were estimated in the coastal sediments of Pakistan. The enrichment and contamination factors (EF and CF) suggested significant influence of anthropogenic and industrial activities along the coastal belt of Pakistan.

Synthetic Developments of Nontoxic Quantum Dots.

PubMed

Das, Adita; Snee, Preston T

2016-03-03

Semiconductor nanocrystals, or quantum dots (QDs), are candidates for biological sensing, photovoltaics, and catalysis due to their unique photophysical properties. The most studied QDs are composed of heavy metals like cadmium and lead. However, this engenders concerns over heavy metal toxicity. To address this issue, numerous studies have explored the development of nontoxic (or more accurately less toxic) quantum dots. In this Review, we select three major classes of nontoxic quantum dots composed of carbon, silicon and Group I-III-VI elements and discuss the myriad of synthetic strategies and surface modification methods to synthesize quantum dots composed of these material systems. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Heavy Metals and Human Health: Mechanistic Insight into Toxicity and Counter Defense System of Antioxidants

PubMed Central

Jan, Arif Tasleem; Azam, Mudsser; Siddiqui, Kehkashan; Ali, Arif; Choi, Inho; Haq, Qazi Mohd. Rizwanul

2015-01-01

Heavy metals, which have widespread environmental distribution and originate from natural and anthropogenic sources, are common environmental pollutants. In recent decades, their contamination has increased dramatically because of continuous discharge in sewage and untreated industrial effluents. Because they are non-degradable, they persist in the environment; accordingly, they have received a great deal of attention owing to their potential health and environmental risks. Although the toxic effects of metals depend on the forms and routes of exposure, interruptions of intracellular homeostasis include damage to lipids, proteins, enzymes and DNA via the production of free radicals. Following exposure to heavy metals, their metabolism and subsequent excretion from the body depends on the presence of antioxidants (glutathione, α-tocopherol, ascorbate, etc.) associated with the quenching of free radicals by suspending the activity of enzymes (catalase, peroxidase, and superoxide dismutase). Therefore, this review was written to provide a deep understanding of the mechanisms involved in eliciting their toxicity in order to highlight the necessity for development of strategies to decrease exposure to these metals, as well as to identify substances that contribute significantly to overcome their hazardous effects within the body of living organisms. PMID:26690422

Bioleaching of heavy metals from sewage sludge: a review.

PubMed

Pathak, Ashish; Dastidar, M G; Sreekrishnan, T R

2009-06-01

During the treatment of sewage, a huge volume of sludge is generated, which is disposed of on land as soil fertilizer/conditioner due to the presence of nitrogen, phosphorus, potassium and other nutrients. However, the presence of toxic heavy metals and other toxic compounds in the sludge restricts its use as a fertilizer. Over the years, bioleaching has been developed as an environmentally friendly and cost-effective technology for the removal of heavy metals from the sludge. The present paper gives an overview of the various bioleaching studies carried out in different modes of operation. The various important aspects such as pathogen destruction, odor reduction and metal recovery from acidic leachate also have been discussed. Further, a detailed discussion was made on the various technical problems associated with the bioleaching process, which need to be addressed while developing the process on a larger scale.

Enhanced Toxic Metal Accumulation in Engineered Bacterial Cells Expressing Arabidopsis thaliana Phytochelatin Synthase

PubMed Central

Sauge-Merle, Sandrine; Cuiné, Stéphan; Carrier, Patrick; Lecomte-Pradines, Catherine; Luu, Doan-Trung; Peltier, Gilles

2003-01-01

Phytochelatins (PCs) are metal-binding cysteine-rich peptides, enzymatically synthesized in plants and yeasts from glutathione in response to heavy metal stress by PC synthase (EC 2.3.2.15). In an attempt to increase the ability of bacterial cells to accumulate heavy metals, the Arabidopsis thaliana gene encoding PC synthase (AtPCS) was expressed in Escherichia coli. A marked accumulation of PCs was observed in vivo together with a decrease in the glutathione cellular content. When bacterial cells expressing AtPCS were placed in the presence of heavy metals such as cadmium or the metalloid arsenic, cellular metal contents were increased 20- and 50-fold, respectively. We discuss the possibility of using genes of the PC biosynthetic pathway to design bacterial strains or higher plants with increased abilities to accumulate toxic metals, and also arsenic, for use in bioremediation and/or phytoremediation processes. PMID:12514032

Soil enzymes as biodiagnostics indicator of heavy metal pollution of urbanozem

NASA Astrophysics Data System (ADS)

Novosyolova, E. I.; Volkova, O. O.; Turyanova, R. R.

2018-01-01

The article presents a comparative analysis of the impact of the introduction of different doses of copper and cadmium on the activity of redox enzymes of urbanozem, collected from different territories of Ufa. The studies established the inverse relationship of the activity of catalase and polyphenol oxidase, and the direct one of the activity of peroxidase that depends on the doses of heavy metals, that allows to recommend their use as bioindicator of pollution of urbanozem with these metals. The reaction of the studied enzymes on the introduction of heavy metals is an indicator of their toxicity to living things at the molecular level. Comparative analysis of the impact of cadmium and copper in different doses on the activity of soil enzymes did not reveal a uniform regularity. Each of the metals showed their toxicity in different ways depending on the duration of their impact.

The use of feather as an indicator for heavy metal contamination in house crow (Corvus splendens) in the Klang area, Selangor, Malaysia.

PubMed

Janaydeh, Mohammed; Ismail, Ahmad; Zulkifli, Syaizwan Zahmir; Bejo, Mohd Hair; Aziz, Nor Azwady Abd; Taneenah, Ayat

2016-11-01

The Klang area of Peninsular Malaysia has experienced rapid industrial growth with intense activities, which can increase the concentration of pollutants in the environment that significantly impact on habitats and the human health. The purpose of this study was to determine the levels of selected heavy metals (Cu, Zn, Ni, Fe, and Pb) in the heart, lung, brain, liver, kidney, muscle tissues, and feathers of house crow, Corvus splendens, in Klang, Peninsular Malaysia. House crow samples were collected from the Klang area through the Department of Public Health at Majlis Perbandaran Klang. Quantitative determination of heavy metals was carried out using atomic absorption spectrophotometer (AAS). The result shows the presence of heavy metals in all biological samples of house crows. For heavy metals in all the house crow tissues analyzed, Fe concentrations were the highest, followed by those of Zn, Cu, Pb, and Ni. The feathers and kidney accumulated high concentrations of Pb, whereas the liver accumulated high concentrations of essential heavy metals (Fe > Zn > Cu > Ni). Significant variations were also detected in the concentrations of Pb among adult and juvenile and male and female bird samples. The results also revealed significant positive correlations between Pb metal concentration in the breast feathers and all internal organs. Accumulation of toxic heavy metals in feathers reflected storing and elimination processes, while the accumulation of toxic heavy metals in the kidney can be consequential to chronic exposure. The present study clearly shows the usefulness of house crow breast feather as a suitable indicator for heavy metal accumulation in the internal organs of house crows in the Klang area.

Effects of conversion of mangroves into gei wai ponds on accumulation, speciation and risk of heavy metals in intertidal sediments.

PubMed

Li, Rongyu; Qiu, Guo Yu; Chai, Minwei; Shen, Xiaoxue; Zan, Qijie

2018-06-23

Mangroves are often converted into gei wai ponds for aquaculture, but how such conversion affects the accumulation and behavior of heavy metals in sediments is not clear. The present study aims to quantify the concentration and speciation of heavy metals in sediments in different habitats, including gei wai pond, mangrove marsh dominated by Avicennia marina and bare mudflat, in a mangrove nature reserve in South China. The results showed that gei wai pond acidified the sediment and reduced its electronic conductivity and total organic carbon (TOC) when compared to A. marina marsh and mudflat. The concentrations of Cd, Cu, Zn and Pb at all sediment depths in gei wai pond were lower than the other habitats, indicating gei wai pond reduced the fertility and the ability to retain heavy metals in sediment. Gei wai pond sediment also had a lower heavy metal pollution problem according to multiple evaluation methods, including potential ecological risk coefficient, potential ecological risk index, geo-accumulation index, mean PEL quotients, pollution load index, mean ERM quotients and total toxic unit. Heavy metal speciation analysis showed that gei wai pond increased the transfer of the immobilized fraction of Cd and Cr to the mobilized one. According to the acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) analysis, the conversion of mangroves into gei wai pond reduced values of ([SEM] - [AVS])/f oc , and the role of TOC in alleviating heavy metal toxicity in sediment. This study demonstrated the conversion of mangrove marsh into gei wai pond not only reduced the ecological purification capacity on heavy metal contamination, but also enhanced the transfer of heavy metals from gei wai pond sediment to nearby habitats.

In situ formation of phosphate barriers in soil

DOEpatents

Moore, Robert C.

2002-01-01

Reactive barriers and methods for making reactive barriers in situ in soil for sequestering soil ontaminants including actinides and heavy metals. The barrier includes phosphate, and techniques are disclosed for forming specifically apatite barriers. The method includes injecting dilute reagents into soil in proximity to a contamination plume or source such as a waste drum to achieve complete or partial encapsulation of the waste. Controlled temperature and pH facilitates rapid formation of apatite, for example, where dilute aqueous calcium chloride and dilute aqueous sodium phosphate are the selected reagents. Mixing of reagents to form precipitate is mediated and enhanced through movement of reagents in soil as a result of phenomena including capillary action, movement of groundwater, soil washing and reagent injection pressure.

Impact erosion of the primordial atmosphere of Mars.

PubMed

Melosh, H J; Vickery, A M

1989-04-06

Abundant geomorphic evidence for fluvial processes on the surface of Mars suggests that during the era of heavy bombardment, Mars's atmospheric pressure was high enough for liquid water to flow on the surface. Many authors have proposed mechanisms by which Mars could have lost (or sequestered) an earlier, thicker atmosphere but none of these proposals has gained general acceptance. Here we examine the process of atmospheric erosion by impacts and show that it may account for an early episode of atmosphere loss from Mars. On the basis of this model, the primordial atmospheric pressure on Mars must have been in the vicinity of 1 bar, barring other sources or sinks of CO2. Current impact fluxes are too small to erode significantly the present martian atmosphere.

Risk assessment of an abandoned pyrite mine in Spain based on direct toxicity assays.

PubMed

García-Gómez, Concepción; Sánchez-Pardo, Beatriz; Esteban, Elvira; Peñalosa, Jesús Manuel; Fernández, María Dolores

2014-02-01

This research reports the risk assessment of an abandoned pyrite mine using direct toxicity assays of soil and groundwater samples taken at the site. The toxicity of As and heavy metals from mining soils to soil and aquatic organisms was studied using the Multispecies Soil System (MS-3) in soil columns. Ecotoxicological assessment was performed with soil samples diluted with a control soil at concentrations of 12.5, 25, 50 and 100% test soil/soil (w/w). In this way, changes in the mobility and bioavailability of soil contaminants due to changes in geochemical soil properties via soil dilution were studied. The toxicity of water samples was tested on algae and Daphnia magna. The assessment of the mining area indicated that the current presence of As and heavy metals at the site may cause injuries to soil and aquatic organisms in the entire research area. Moreover, this investigation demonstrated that changes in geochemical conditions can increase the availability of arsenic and, consequently, the environmental risk of these soils. A good correlation was not found between toxicity parameters and the concentrations of soil contaminants based on total and extracted element concentrations. This finding reinforces the usefulness of direct toxicity assays for evaluating environmental risk. © 2013.

Assessment of sediment contamination by spermiotoxicity and embryotoxicity bioassays with sea urchins (Paracentrotus lividus) and oysters (Crassostrea gigas).

PubMed

Geffard, O; Budzinski, H; Augagneur, S; Seaman, M N; His, E

2001-07-01

Gametes (sperm) and fertilized eggs (embryos) of the Mediterranean sea urchin, Paracentrotus lividus, and the Japanese oyster, Crassostrea gigas, were used to investigate the toxicity of two marine sediments, one polluted by polycyclic aromatic hydrocarbons (PAH) and the other by heavy metals. The sediment samples were freeze-dried for storage, and three different treatments were used for analysis: whole sediment, unfiltered elutriate, and filtered elutriate. The two sediments were toxic to sea urchin spermatozoa but not to oyster spermatozoa, and embryotoxicity was almost always the more sensitive endpoint for toxicity assessment. As a rule, whole sediment was more toxic than the elutriates by nearly two orders of magnitude. With respect to embryotoxicity, the whole sediments and the elutriates of the PAH-contaminated sediment were more toxic to oyster embryos, whereas the elutriates of the sediment polluted by heavy metals had stronger effects on sea urchin embryos. The results confirm that bioassays with Japanese oyster embryos provide a more sensitive appraisal of toxicity in the marine environment than bioassays with other developmental stages. As a whole, Mediterranean sea urchins and Japanese oysters were similar in overall sensitivity and are therefore both equally suited as bioassay organisms, but tests with oysters are more reproducible because of the better performance of the controls.

Effect of Nano-Al₂O₃ on the Toxicity and Oxidative Stress of Copper towards Scenedesmus obliquus.

PubMed

Li, Xiaomin; Zhou, Suyang; Fan, Wenhong

2016-06-09

Nano-Al₂O₃ has been widely used in various industries; unfortunately, it can be released into the aquatic environment. Although nano-Al₂O₃ is believed to be of low toxicity, it can interact with other pollutants in water, such as heavy metals. However, the interactions between nano-Al₂O₃ and heavy metals as well as the effect of nano-Al₂O₃ on the toxicity of the metals have been rarely investigated. The current study investigated copper toxicity in the presence of nano-Al₂O₃ towards Scenedesmus obliquus. Superoxide dismutase activity and concentration of glutathione and malondialdehyde in cells were determined in order to quantify oxidative stress in this study. Results showed that the presence of nano-Al₂O₃ reduced the toxicity of Cu towards S. obliquus. The existence of nano-Al₂O₃ decreased the growth inhibition of S. obliquus. The accumulation of copper and the level of oxidative stress in algae were reduced in the presence of nano-Al₂O₃. Furthermore, lower copper accumulation was the main factor that mitigated copper toxicity with the addition of nano-Al₂O₃. The decreased copper uptake could be attributed to the adsorption of copper onto nanoparticles and the subsequent decrease of available copper in water.

Morphological and physiological responses of plants to cadmium toxicity: A review

USDA-ARS?s Scientific Manuscript database

Since the dawn of industrial revolution, anthropogenic activities have accelerated release of hazardous heavy metals, such as cadmium (Cd), copper (Cu), lead (Pb), chromium (Cr) and mercury (Hg) to the environment. Cadmium is toxic to animals and plants. Its bioaccumulation in food chain has surpass...

Differences in how rice plants processes arsenic in their cells

USDA-ARS?s Scientific Manuscript database

Arsenic (As), a carcinogenic heavy metal, is a problem in some drinking water and staple food supplies around the world. Rice plants readily uptake arsenic and transport a portion of it into the grain. Arsenic is also toxic to plants; therefore mechanisms that reduce toxicity or accumulation have ev...

EFFECT OF SOIL MODIFYING FACTORS ON THE BIOAVAILABILITY AND TOXICITY OF METAL CONTAMINATED SOILS

EPA Science Inventory

Heavy metal and organic chemical contamination of soils is a worldwide problem posing a risk to humans and more directly, soil organisms. Metal toxicity is often not directly related to the total concentration of metals present due to a number of modifying factors that depend,...

ACUTE TOXICITY OF HEAVY METALS TO ACETATE-UTILIZING MIXED CULTURES OF SULFATE-REDUCING BACTERIA: EC100 AND EC50

EPA Science Inventory

Acid mine drainage (AMD) from abandoned mines and acid mine pitlakes is an important environmental contaminant concern and usually contains appreciable concentrations of heavy metals. Since sulfate-reducing bacteria (SRB) are involved in the treatment of AMD, knowledge of acute m...

Base-treated juniper fiber media for removing heavy metals in stormwater runoff

Treesearch

S.-H. Min; Thomas Eberhardt; Jang Min

2007-01-01

The viability of base-treated juniper fiber (BTJF) media for removing toxic heavy metals (Cd2+, Cu2+, Pb2+, Zn2+) in stormwater runoff was investigated. The sorption ability ofthe BTJF for all metals was much higher than that of untreated juniper. The affinity sequence of both...

EVALUATION OF RETENTION POND AND CONSTRUCTED WETLAND BMPS FOR TREATING PARTICULATE-BOUND HEAVY METALS IN URBAN STORMWATER RUNOFF

EPA Science Inventory

Urban stormwater discharge during wet-weather flows is a major contributor to the pollution of many receiving waters. Heavy metals are of particular interest in stormwater runoff due to their toxicity, ubiquitousness, and their inability to degrade in the environment. The sources...

Utilization of a duckweed bioassay to evaluate leaching of heavy metals in smelter contaminated soils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Youngman, A.L.; Lydy, M.J.; Williams, T.L.

1998-12-31

The purpose of this study was to determine whether a duckweed bioassay could be used to evaluate the downward migration of heavy metals in smelter soils. The duckweed bioassay was initially used to evaluate elutriates prepared from samples of smelter soils. These initial tests verified that the elutriates would elicit toxic responses. Elutriate testing was followed with an evaluation of leachate from untreated soil cores or soil cores that had been amended with organic matter either unplanted or planted to a grass-forb seed mixture. There was an inverse linear relationship between heavy-metal concentrations in leachate and NOEC and IC{sub 50}more » values expressed as percentages among all soil cores. Based on these preliminary duckweed bioassays, there were no differences between soil types or organic amended or non-amended soil, but leachate from vegetated soil cores were less toxic than were leachates from non-vegetated soil cores. Overall, the duckweed bioassays were useful in detecting heavy metal availability in elutriate and leachate samples from smelter soils.« less

Soil quality changes in response to their pollution by heavy metals, Georgia.

PubMed

Matchavariani, Lia; Kalandadze, Besik; Lagidze, Lamzira; Gokhelashvili, Nino; Sulkhanishvili, Nino; Paichadze, Nino; Dvalashvili, Giorgi

2015-01-01

The present study deals with the composition, migration and accumulation of heavy metals in irrigated soils, plants and partially natural waters; and also, establishing the possible sources of pollution and their impact on environmental situation. The content of toxic elements in the irrigated soils adjacent to ore mining and processing enterprise were studied. Content of toxic elements in the irrigated soils adjacent to ore mining, showed that more than half of territory was seriously polluted by copper and zinc. Some part of the area were considered catastrophically polluted. Expressed technogenesis taking place influenced irrigation. Heavy metals like copper, zinc and manganese negative by effected the properties of soil, thus composition and soil-forming processes taking place in the soil. It was especially well represented in the deterioration of hydro-physical potential of the soil. Irrigation of agricultural land plots by water, polluted with heavy metals changed the pH. Balanced correlation among solid, liquid and gas phases was disrupted. In highly polluted soil, the cementing processes took place that sharply increased the bulk density of the soil, deteriorated the porosity of soil and reduced water permeability critically.

Effect of cadmium on the bioelement composition of Nostoc UAM208: Interaction with calcium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fernandez-Pinas, F.; Mateo, P.; Bonilla, I.

1997-04-01

Heavy metals may cause effects on the cyanobacterial cell including possible damage to the membranes and leakage from cells resulting in the loss or reduction of essential bioelements. There are many reports in the literature concerning morphological, biochemical and physiological changes caused by cadmium in cyanobacteria, but data on the influence of cadmium on the ion balance of the cell dealing with the interactive effect of cadmium and calcium are limited. Calcium has been found to exert a protective role against heavy metal toxicity in a variety of organisms, We previously reported that calcium is able to counteract the toxicmore » effect of cadmium towards growth, photosynthesis, nitrogenase activity and pigment content of the cyanobacterium Nostoc UAM208. In the present study, we analyzed the content of essential ions, as affected by cadmium treatment, to search for possible mechanisms of heavy metal damage and toxicity in Nostoc. We also studied whether calcium enrichment (1.1 mM final concentration) has any influence on the heavy metal effect on those ionic contents. 13 refs., 2 figs.« less

Database Assessment of the Health and Environmental Effects of Munition Production Waste Products

DTIC Science & Technology

1984-08-01

manufacture heavy metals are apparently leached P from the nitrating vessels as a result of the action of the nitrating acid mixture. Attempts to remove...characterize these inorganic pollu- tants, but two reports (Chen et al. 1981 and Ribaudo et al. 1981) iden- tify heavy metals and inorganic ions present...in wastewater effluents from munition plants. Three of the heavy metals (cadmium, chromium, and copper) are of concern because of their known toxic

Heavy Metals in Marine Pollution Perspective-A Mini Review

NASA Astrophysics Data System (ADS)

Ansari, T. M.; Marr, I. L.; Tariq, N.

Anthropogenic inputs of pollutants such as heavy metals into the marine environment have increased their levels to large extents within past a few decades. These pollutants tend to accumulate in the bottom sediments. As a result, ecosystems such as seaports or other industrialized coastal areas that have chronic inputs of metals have highly contaminated sediments. This characteristic has led to concerns over the ecological effects that may be associated with sediment quality. Of particular concern are toxic effects and the potential for bioaccumulation of metals in biota exposed to the sediments. The availability of heavy metals to the biomass of a polluted region is the prime concern both in terms of the prediction of the effects of metal pollution on an ecosystem and in terms of possible human health risks. With growing interest on environmental issues, several intriguing questions related to heavy metals are often raised. This review addresses the basic concepts, sources, speciation, mode of action, levels, analytical measurement, bioavailability, bioaccumulation, biological role and toxicity of heavy metals in the marine environment. Lead, Cadmium, Zinc, Copper, Manganese, Iron, Mercury, Arsenic and Barium are selected because these metals are common and are often at measurable levels in marine samples. An attempt has been made to answer the queries presented by the environmentalists working on various aspects of heavy metal pollution in the marine environment

[Cd, Cu, Zn and Pb contents and forms in soils and rapeseeds around Wuhu Plant].

PubMed

Wang, Xingming; Liu, Dengyi; Tu, Junfang; Li, Zheng; Wang, Youbao

2005-10-01

The study showed that around Wuhu Plant, soil Cd, Zn and Pb mainly existed in Fe-Mn oxide form, and Cu in residual form, with the percentage of 31.81%, 39.83%, 53.79%, and 46.24%, respectively. Soil exchangeable Cd and Pb had a higher proportion (23.47% and 16.32%) than soil exchangeable Cu and Zn (3.14% and 0.54%). The correlations between soil heavy metals and their forms, as well as their transformation to available form were different. Different heavy metals had different accumulation trends in rapeseed and its hull. Cu easily accumulated in hull, while Cd, Zn and Pb had a higher accumulation in seed. The accumulation rate of heavy metals in rapeseed and hull was also different, being the highest for Cd. There was a significantly negative correlation (P < 0.05) between the accumulation rate of heavy metals and their contents in soil. In rapeseed, Cd, Cu and Pb were mainly in sodium hydroxide form, with the percentage of 32.50%, 22.94% and 34.69%, respectively, while Zn was mainly in EDTA form, with a percentage of 45.97. The existed forms of heavy metals in rapeseed probably affected their toxicity, but the toxicity to human food could not be inferred from this research, and needed to be studied further. There was a weak relation between heavy metals contents and their existed forms in rapeseed.

Impact of industrial effluent on growth and yield of rice (Oryza sativa L.) in silty clay loam soil.

PubMed

Anwar Hossain, Mohammad; Rahman, Golum Kibria Muhammad Mustafizur; Rahman, Mohammad Mizanur; Molla, Abul Hossain; Mostafizur Rahman, Mohammad; Khabir Uddin, Mohammad

2015-04-01

Degradation of soil and water from discharge of untreated industrial effluent is alarming in Bangladesh. Therefore, buildup of heavy metals in soil from contaminated effluent, their entry into the food chain and effects on rice yield were quantified in a pot experiment. The treatments were comprised of 0, 25%, 50%, 75% and 100% industrial effluents applied as irrigation water. Effluents, initial soil, different parts of rice plants and post-harvest pot soil were analyzed for various elements, including heavy metals. Application of elevated levels of effluent contributed to increased heavy metals in pot soils and rice roots due to translocation effects, which were transferred to rice straw and grain. The results indicated that heavy metal toxicity may develop in soil because of contaminated effluent application. Heavy metals are not biodegradable, rather they accumulate in soils, and transfer of these metals from effluent to soil and plant cells was found to reduce the growth and development of rice plants and thereby contributed to lower yield. Moreover, a higher concentration of effluent caused heavy metal toxicity as well as reduction of growth and yield of rice, and in the long run a more aggravated situation may threaten human lives, which emphasizes the obligatory adoption of effluent treatment before its release to the environment, and regular monitoring by government agencies needs to be ensured. Copyright © 2015. Published by Elsevier B.V.

Treatment and Reuse of Wastewaters Discharged by Petroleum Industries (HMD/Algeria)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sellami, MH, E-mail: sellami2000dz@gmail.com; Loudiyi, K; Boubaker, MC

Industrial wastewaters discharged by petroleum industries contains: oil, heavy metals and chemicals used in the process of oil separation and treatment. These waters are a source of soil, water and air pollution, and lead a mortal danger to the ecosystem. Our aim in this work has an aspect that can contribute to the collective effort to address the enormous amount of water purges storage bins and reuse them to avoid any environmental damage. This was achieved by chemical treating of these wastewaters discharged from three different locations of Hassi Messaoud (HMD) petroleum field by flocculation with (C-5563) followed by coagulationmore » with (C-2061) using two different acids as sequestering namely: Ascorbic and Citric acid. After experiments, the results showed that the wastewater can be treated without sequestering by adding 40 ppm of activated silicates. The best result was obtained by addition of 160 ppm of Ascorbic acid as sequestering agent and 20 ppm of activated silicates; resulting in removal of 92.81 % of suspended matter and 95.53 % of turbidity. Finally we concluded that this wastewater was satisfactorily treated and we recommend either inject it for enhanced oil recovery in industrial closest field (North field) to maintain the reservoir pressure and the improved rate recovery of oil reserves or reuse it in garden irrigation. In order to see the impact of the treated water on plants, irrigation tests have conducted on two types of plants (date palm and shaft apocalyptic) for one year. The tests showed that the thick layer of 5 cm and 0.08mm of particles diameter of dune sand removes most of remaining oil. The sand layer that fills the basin surrounding the shaft is removed and replaced every 06 months. So, Dune sand plays the role of natural filter. The garden plants appear and grow normally.« less

Cadmium, lead, and zinc mobility and plant uptake in a mine soil amended with sugarcane straw biochar.

PubMed

Puga, A P; Abreu, C A; Melo, L C A; Paz-Ferreiro, J; Beesley, L

2015-11-01

Accumulation of heavy metals in unconsolidated soils can prove toxic to proximal environments, if measures are not taken to stabilize soils. One way to minimize the toxicity of metals in soils is the use of materials capable of immobilizing these contaminants by sorption. Biochar (BC) can retain large amounts of heavy metals due to, among other characteristics, its large surface area. In the current experiment, sugarcane-straw-derived biochar, produced at 700 °C, was applied to a heavy-metal-contaminated mine soil at 1.5, 3.0, and 5.0% (w/w). Jack bean and Mucuna aterrima were grown in pots containing a mine contaminated soil and soil mixed with BC. Pore water was sampled to assess the effects of biochar on zinc solubility, while soils were analyzed by DTPA extraction to confirm available metal concentrations. The application of BC decreased the available concentrations of Cd, Pb, and Zn in the mine contaminated soil leading to a consistent reduction in the concentration of Zn in the pore water. Amendment with BC reduced plant uptake of Cd, Pb, and Zn with the jack bean uptaking higher amounts of Cd and Pb than M. aterrima. This study indicates that biochar application during mine soil remediation could reduce plant concentrations of heavy metals. Coupled with this, symptoms of heavy metal toxicity were absent only in plants growing in pots amended with biochar. The reduction in metal bioavailability and other modifications to the substrate induced by the application of biochar may be beneficial to the establishment of a green cover on top of mine soil to aid remediation and reduce risks.

Monitoring heavy metals, residual agricultural chemicals and sulfites in traditional herbal decoctions.

PubMed

Yu, In-Sil; Lee, Jeong-Sook; Kim, Sung-Dan; Kim, Yun-Hee; Park, Hae-Won; Ryu, Hoe-Jin; Lee, Jib-Ho; Lee, Jeong-Mi; Jung, Kweon; Na, Cheol; Joung, Jin-Yong; Son, Chang-Gue

2017-03-14

Asian traditional herbal preparations are frequently considered for the contamination with undeclared toxic or hazardous substances. The aim of this study was to determine the toxic heavy metals, pesticides and sulfur dioxide in decoctions that is a common form of final utilization in Korea. A total of 155 decoctions composed of multi-ingredient traditional herbs were randomly sampled from Seoul in Korea between 2013 and 2014. For each decoction, the concentrations of four heavy metals (arsenic, cadmium, lead and mercury), 33 pesticides and sulfur dioxide were analyzed using inductively coupled plasma mass spectrometry (ICP-MS), mercury analyzer, gas chromatography/nitrogen phosphorous detector (GC/NPD), gas chromatography/micro electron capture detector (GC/μECD), and Monier-Williams method respectively. One hundred fifty-two of One hundred fifty-five decoctions (98.1%) contained one of three heavy metals (96.1% for As, 97.4% for Cd, and 90.3% for Pb, 0.0% for Hg). Their average concentrations (77.0 ± 79.7 ug/kg for As, 20.4 ± 23.7 ug/kg for Cd, and 68.8 ± 76.5 ug/kg for Pb) were approximately 20% of the maximum allowable limits of vegetable or ginseng beverage described in the Korean Food Standard Codex while their 95th percentile concentrations were below than the guideline for them. None of 33 pesticides was detected in 155 decoction samples, and only one sample showed over limit of detection for residual sulfites. This study support that the contained status of toxic heavy metals, pesticides and sulfur dioxide in herbal decoctions are currently within safe level in Korea, and provide a reference data for the further studies focused on the safety herbal preparations.

Toxic effects of selenium and copper on the planarian, Dugesia dorotocephala

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rauscher, J.D.

1988-01-01

Aquatic toxicologists have become increasingly concerned with the effects of sublethal concentrations of toxicants on aquatic organisms. Sublethal effects of toxicants on freshwater invertebrates were reviewed. Selenium (Se) and copper (Cu) are both essential trace elements and toxicants. Se has been reported to alter the toxicity of heavy metals. Planarians, Dugesia dorotocephala, were used as test animals. The objectives of this study were to determine: (1) acute toxicity of Se on planarians and the effect of the number of planarians per test chamber, (2) interaction of the acute toxicity of Se and Cu on planarians, and (3) sublethal effects ofmore » Se and Cu on planarians.« less

Potentially toxic elements and environmentally-related pollutants recognition using colorimetric and ratiometric fluorescent probes.

PubMed

Rasheed, Tahir; Li, Chuanlong; Bilal, Muhammad; Yu, Chunyang; Iqbal, Hafiz M N

2018-05-30

A safer detection or sensing of toxic pollutants is one among several environmental contamination issues, across the globe. The ever-increasing industrial practices and controlled or uncontrolled release of toxic pollutants from various industrial sectors is a key source of this environmental problem. Significant research efforts have been or being made to tackle this problematic issue to fulfill the growing needs of the modern world. Despite many useful aspects, heavy metals are posing noteworthy toxicological concerns and human-health related issues at various levels of the ecosystem. In this context, notable efforts from various regulatory authorities, the increase in the concentration of these toxic heavy metals in the environment is of serious concern, so real-time monitoring is urgently required. Herein, we reviewed fluorescent sensor based models and their potentialities to address the detection fate of hazardous pollutants including chromium, manganese, cobalt, nickel, copper, and zinc as model elements. The novel aspects of turn-on/off fluorescent sensors have also been discussed from a state of the art viewpoint. In summary, comprehensive literature regarding fluorescent sensor based models and their potentialities to detect various types of toxic pollutants is reviewed. Copyright © 2018 Elsevier B.V. All rights reserved.

Jointed toxicity of TiO2 NPs and Cd to rice seedlings: NPs alleviated Cd toxicity and Cd promoted NPs uptake.

PubMed

Ji, Ye; Zhou, Yun; Ma, Chuanxin; Feng, Yan; Hao, Yi; Rui, Yukui; Wu, Wenhao; Gui, Xin; Le, Van Nhan; Han, Yaning; Wang, Yingcai; Xing, Baoshan; Liu, Liming; Cao, Weidong

2017-01-01

Previous studies have reported that nanoparticles (NPs) and heavy metals are toxic to the environment. However, the jointed toxicity is not yet well understood. This study was aimed to investigate the combined toxicity of TiO 2 NPs and the heavy metal cadmium (Cd) to plants. Rice (Oryzasativa L.) was selected as the target plant. The rice seedlings were randomly separated into 12 groups and treated with CdCl 2 (0, 10 and 20 mg/L) and TiO 2 NPs (0, 10, 100 and 1000 mg/L). The plant height, biomass and root length indicated significant toxicity of Cd to the growth, but TiO 2 NPs exhibited the potential ability to alleviate the Cd toxicity. Transmission electron microscopy (TEM) and energy dispersive spectrometer (EDS) confirmed the existence of TiO 2 NPs in plants. Elemental analysis of Ti and Cd suggested that the presences of Cd significantly decreased the Ti accumulation in the rice roots in the co-exposure treatments. Interestingly, TiO 2 NPs could lower the Cd uptake and distribution in rice roots and leaves. The results of antioxidant enzyme activity, lipid peroxide as well as phytohormones varied in the different treatments. Comparing with the Cd alone treatment, the net photosynthetic rate and chlorophyll content were significantly increased in the co-exposure treatments, suggesting that TiO 2 NPs could tremendously reduce the Cd toxicity. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Effects of an aged copper contamination on distribution of earthworms, reproduction and cocoon hatchability.

PubMed

Mirmonsef, Hassan; Hornum, Hanne D; Jensen, John; Holmstrup, Martin

2017-01-01

Contaminated soil is a problem throughout the industrialized world, and a significant proportion of these sites are polluted with heavy metals such as copper. Ecological risk assessment of contaminated sites requires ecotoxicological studies with spiked soils as well as in-situ ecological observations. Here, we report laboratory and field assessment of copper toxicity for earthworms at a Danish site (Hygum) exclusively contaminated with an increasing gradient in copper from background to highly toxic levels (>1000mgkg -1 dry soil). More specifically, we report effects on field populations, body contents of copper, hatching of earthworm cocoons and reproduction of the common species Aporrectodea tuberculata. Abundance of earthworms and cocoons decreased significantly from about 400-150m -2 along the gradient as the soil copper concentration increased from ca. 50 to ca. 1000mgkg -1 . At lower concentrations, the population was dominated by endogeic species, whereas at high concentrations the population was dominated by epigeic species. At high copper contents the internal concentration of copper was in the range 100-160mgkg -1 dry tissue. Despite the high internal copper contents, hatchability of field collected cocoons was not impaired in any species. The EC50 reproduction value of A. tuberculata was about 220mg copper kg -1 dry soil in the first two exposure periods, but nearly doubled in the third period suggesting that an acclimation response had occurred. Also in the laboratory reproduction test, cocoon hatchability was not reduced, but rather slightly stimulated by copper. Based on these results we discuss the possibility that acute exposure in laboratory experiments is more detrimental than exposure in a field situation, perhaps because increased tolerance may be acquired through natural selection and genetic adaptation through increased use of defense mechanisms such as metallothioneins. Further, we discuss that the rather high tissue copper level of earthworms from the Hygum site may have smaller effects in these free-ranging worms than it would have in acute-exposure laboratory tests because the copper is more efficiently sequestered and detoxified in the field situation where populations have been exposed for many generations. Copyright © 2016 Elsevier Inc. All rights reserved.

Compartmentalization of superoxide dismutase 1 (SOD1G93A) aggregates determines their toxicity

PubMed Central

Weisberg, Sarah J.; Lyakhovetsky, Roman; Werdiger, Ayelet-chen; Gitler, Aaron D.; Soen, Yoav; Kaganovich, Daniel

2012-01-01

Neurodegenerative diseases constitute a class of illnesses marked by pathological protein aggregation in the brains of affected individuals. Although these disorders are invariably characterized by the degeneration of highly specific subpopulations of neurons, protein aggregation occurs in all cells, which indicates that toxicity arises only in particular cell biological contexts. Aggregation-associated disorders are unified by a common cell biological feature: the deposition of the culprit proteins in inclusion bodies. The precise function of these inclusions remains unclear. The starting point for uncovering the origins of disease pathology must therefore be a thorough understanding of the general cell biological function of inclusions and their potential role in modulating the consequences of aggregation. Here, we show that in human cells certain aggregate inclusions are active compartments. We find that toxic aggregates localize to one of these compartments, the juxtanuclear quality control compartment (JUNQ), and interfere with its quality control function. The accumulation of SOD1G93A aggregates sequesters Hsp70, preventing the delivery of misfolded proteins to the proteasome. Preventing the accumulation of SOD1G93A in the JUNQ by enhancing its sequestration in an insoluble inclusion reduces the harmful effects of aggregation on cell viability. PMID:22967507

Redox and fungicidal properties of phthalocyanine metal complexes as related to active oxygen.

PubMed

Vol'pin, M E; Novodarova, G N; Krainova NYu; Lapikova, V P; Aver'yanov, A A

2000-10-01

Some chemical and fungicidal effects of 20 phthalocyanines of Co, Fe, Cu, and Al were studied. Under dark conditions, these complexes reduced nitroblue tetrazolium in the presence of KCN, accelerated the autoxidation of ascorbate or hydroquinone and decomposed hydrogen peroxide. In the later reaction, hydroxyl radical was generated as evidenced with the deoxyribose assay. The inhibition by superoxide dismutase and catalase of catalyzed autoxidation of ascorbate suggests the participation of superoxide anion-radical and hydrogen peroxide in the reaction. Most complexes were toxic to the fungus Magnaporthe grisea which causes blast disease of rice. The toxicity was enhanced by light being diminished by antioxidant reagents sequestering active oxygen species. Some complexes (including nontoxic ones), after 1-day contact with a leaf surface of the disease-susceptible rice cultivar, induced the fungitoxicity of leaf diffusate. This toxicity was also light-activated and sensitive to antioxidant reagents. Several complexes, when added to inocula, decreased 2-3 times the frequency of the compatible symptoms of the blast. It is suggested that in planta, the dark redox activity of phthalocyanines along with their photosensitization promote the generation of active oxygen, which damages the parasite and, therefore, favors disease resistance.

Feeding on toxic prey. The praying mantis (Mantodea) as predator of poisonous butterfly and moth (Lepidoptera) caterpillars.

PubMed

Mebs, Dietrich; Wunder, Cora; Pogoda, Werner; Toennes, Stefan W

2017-06-01

Caterpillars of the monarch butterfly, Danaus plexippus, feed on milkweed plants, Asclepias spp. (Apocynaceae), and sequester their toxic cardenolides aimed at deterring predators. Nevertheless, Chinese praying mantids, Tenodera sinensis, consume these caterpillars after removing the midgut ("gutting") including its plant content. In the present study, monarch caterpillars raised on A. curassavica, and those of the death's-head hawkmoth, Acherontia atropos, raised on Atropa belladonna containing atropine, were fed to mantids, Hierodula membranacea, which removed the gut of both species discarding about 59% of cardenolides and more than 90% of atropine, respectively. The ingestion of these compounds produced no apparent ill effects in the mantids and both were excreted with faeces. On the other hand, when mantids were fed with larvae of two moth species, Amata mogadorensis and Brahmaea certia, raised on non-poisonous host plants, the mantids showed the same gutting behaviour, thereby discarding indigestible plant material. As polar compounds, e.g. cardenolides and atropine, are not absorbed from the mantids midgut and do not pass the gut membrane, this enables the mantids to feed on toxic prey. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigation of Media Effects on Removal of Heavy Metals in Bioretention Cells

NASA Astrophysics Data System (ADS)

Gülbaz, Sezar; Melek Kazezyilmaz-Alhan, Cevza; Copty, Nadim K.

2015-04-01

Heavy metals are the most toxic elements at high concentrations, although some of them such as Cu and Zn are essential to plants, humans, and animals within a limited value. However, some heavy metals, such as Pb, have adverse effects even at low concentrations. Therefore, it is known that the toxic metals such as Zn, Cu and Pb in storm water runoff are serious threat for aquatic organisms. It is very important to control and reduce heavy metal concentration in urban storm water runoff. There are several methods to remove the aforementioned toxic metals such as electrolyte extraction, chemical precipitation, ion-exchange, reverse osmosis, membrane filtration, adsorption, cementation, and electrochemical treatment technologies. However, these methods are highly expensive and hard to implement for treatment of big volumes of water such as storm water. For this purpose, Low Impact Development (LID) Best Management Practices (BMPs) have become popular to collect, infiltrate, and treat toxic metals in storm water runoff in recent years. LID-BMP is a land planning method which is used to manage storm water runoff and improve water quality by reducing contaminant in storm water runoff. Bioretention is an example of LID-BMP application of which usage has recently been started in storm water treatment. Researchers have been investigating the advantages of bioretention systems and this study contributes to these research efforts by seeking for the media effects of bioretention on heavy metal removal. For this purpose, batch sorption experiments were performed to determine the distribution coefficients and retardation factor of copper (Cu), lead (Pb), and zinc (Zn) for bioretention media such as mulch, turf, local or vegetative soil, sand and gravel. Furthermore, sorption reaction kinetics of Cu, Pb and Zn are tested in order to assess the sorption equilibrium time of these metals for 5 bioretention media. The results of sorption test show that turf has higher sorption capacity than mulch and local soil for heavy metals used in the experiment. On the other hand, sand and gravel have relatively lower sorption capacities. Linear equilibrium isotherm represents sorption of these metals for all bioretention media. The highest sorption is observed for Pb followed by Cu and Zn for all bioretention media. The time required for reaching equilibrium conditions for bioretention column media is ranged from 1 to 6 hours for each metal investigated.

The Wireless Sensor Network (WSN) Based Coal Ash Impoundments Safety Monitoring System

NASA Astrophysics Data System (ADS)

Sun, E. J.; Nieto, A.; Zhang, X. K.

2017-01-01

Coal ash impoundments are inevitable production of the coal-fired power plants. All coal ash impoundments in North Carolina USA that tested for groundwater contamination are leaking toxic heavy metals and other pollutants. Coal ash impoundments are toxic sources of dangerous pollutants that pose a danger to human and environmental health if the toxins spread to adjacent surface waters and drinking water wells. Coal ash impoundments failures accidents resulted in serious water contamination along with toxic heavy metals. To improve the design and stability of coal ash impoundments, the Development of a Coal Ash Impoundment Safety Monitoring System (CAISM) was proposed based on the implementation of a wireless sensor network (WSN) with the ability to monitor the stability of coal ash impoundments, water level, and saturation levels on-demand and remotely. The monitoring system based on a robust Ad-hoc network could be adapted to different safety conditions.

Acute toxicity of heavy metals for benthic epiphytic foraminifera Pararotalia spinigera (Le Calvez) and influence of seaweed-derived DOC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bresler, V.; Yanko, V.

1995-10-01

The acute toxicity of cadmium, copper, and mercury to the benthic epiphytic foraminiferan Pararotalia spinigera (Le Calvez) was investigated using seven different vital cytophysiological and cytochemical methods. The ability to enzymatically hydrolyze the fluorogenic substrates fluorescein diacetate or fluorescein dibutyrate was the most sensitive method of LC50 value determination. The LC50 (24-h) values for cadmium, copper, and mercury determined by this assay with fluorescein diacetate was 0.56, 1.4, and 0.07 {micro}M, respectively. The content of seaweed-derived dissolved organic carbon (DOC), measured by absorbance at 436 nm, produced a dramatic increase of LC50 values for the heavy metals in a dose-dependentmore » manner. ``Intact`` epiphytic foraminifera attached to seaweeds are less sensitive to acute toxicity of cadmium, copper, and mercury than are ``detached`` foraminifera.« less

Plant growth promoting rhizobacteria and endophytes accelerate phytoremediation of metalliferous soils.

PubMed

Ma, Y; Prasad, M N V; Rajkumar, M; Freitas, H

2011-01-01

Technogenic activities (industrial-plastic, textiles, microelectronics, wood preservatives; mining-mine refuse, tailings, smelting; agrochemicals-chemical fertilizers, farm yard manure, pesticides; aerosols-pyrometallurgical and automobile exhausts; biosolids-sewage sludge, domestic waste; fly ash-coal combustion products) are the primary sources of heavy metal contamination and pollution in the environment in addition to geogenic sources. During the last two decades, bioremediation has emerged as a potential tool to clean up the metal-contaminated/polluted environment. Exclusively derived processes by plants alone (phytoremediation) are time-consuming. Further, high levels of pollutants pose toxicity to the remediating plants. This situation could be ameliorated and accelerated by exploring the partnership of plant-microbe, which would improve the plant growth by facilitating the sequestration of toxic heavy metals. Plants can bioconcentrate (phytoextraction) as well as bioimmobilize or inactivate (phytostabilization) toxic heavy metals through in situ rhizospheric processes. The mobility and bioavailability of heavy metal in the soil, particularly at the rhizosphere where root uptake or exclusion takes place, are critical factors that affect phytoextraction and phytostabilization. Developing new methods for either enhancing (phytoextraction) or reducing the bioavailability of metal contaminants in the rhizosphere (phytostabilization) as well as improving plant establishment, growth, and health could significantly speed up the process of bioremediation techniques. In this review, we have highlighted the role of plant growth promoting rhizo- and/or endophytic bacteria in accelerating phytoremediation derived benefits in extensive tables and elaborate schematic sketches. Copyright © 2010 Elsevier Inc. All rights reserved.

Heavy metal concentrations in the tissue of Sparus sarba Forskal, 1775 from the United Arab Emirates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Ghais, S.M.

1995-10-01

Pollution of the marine environment by inorganic and organic chemicals has been recognised as one of the major factors posing serious threat to the survival of marine organisms including fish. Heavy metal contamination of the marine environment has been reported to cause toxicity to aquatic organisms. Natural processes such as volcanic eruptions, erosion and wind, industrial activities and mining are the major sources of metal contamination. Exposure to heavy metals through air, water and/or the food chain is known to induce a wide variety of toxic effects in humans and animals. Metals such as zinc manganese and copper are toxicmore » only when present in high enough amounts, but at low levels are considered essential as micronutients. Extensive studies have been carried out in Europe and America to determine toxicity and bio-accumulation of these metals in fish and other marine flora and fauna. However, there is a gap in our knowledge of the kind and extent of marine pollution by heavy metals around the coast of the United Arab Emirates (UAE) and the resultant contamination of the aquatic habitat. This study was designed to investigate the concentrations of cadmium, cobalt, copper, manganese, nickel, lead and zinc in the muscle, liver and heart, and mercury in the muscle tissue of Sparus Sarba, one of the more nutritionally popular fish of the UAE region. 11 refs., 3 figs., 2 tabs.« less

The influence of EDDS and EDTA on the uptake of heavy metals of Cd and Cu from soil with tobacco Nicotiana tabacum.

PubMed

Evangelou, Michael W H; Bauer, Uwe; Ebel, Mathias; Schaeffer, Andreas

2007-06-01

Phytoextraction, the use of plants to extract contaminants from soils and groundwater, is a promising approach for cleaning up soils contaminated with heavy metals. In order to enhance phytoextraction the use of chelating agents has been proposed. This study aims to assess whether ethylene diamine disuccinate (EDDS), a biodegradable chelator, can be used for enhanced phytoextraction purposed, as an alternative to ethylene diamine tetraacetate (EDTA). EDDS revealed a higher toxicity to tobacco (Nicotiana tabacum) in comparison to EDTA, but no toxicity to microorganisms. The uptake of Cu was increased by the addition of EDTA and EDDS, while no increase was observed in the uptake of Cd. Both chelating agents showed a very low root to shoot translocation capability and the translocation factor was lower than the one of the control. Heavy metals where significantly more phytoavailable than in the control, even after harvesting, resulting in a high heavy metal leaching possibility, probably owing to a low biodegradation rate of EDDS. New seedlings which were transplanted into the EDDS treated pots 7d after the phytoextraction experiment, showed signs of necrosis and chlorosis, which resulted in a significantly lower biomass in comparison to the control. The seedlings on the EDTA treated pots showed no toxicity signs. Contrary to previous opinions the results of this study revealed the chelating agents EDTA and EDDS as unsuitable for enhanced phytoextraction using tobacco.

Time-response characteristic and potential biomarker identification of heavy metal induced toxicity in zebrafish.

PubMed

Yin, Jian; Wang, Ai-Ping; Li, Wan-Fang; Shi, Rui; Jin, Hong-Tao; Wei, Jin-Feng

2018-01-01

The present work aims to explore the time-response (from 24 h to 96 h) characteristic and identify early potential sensitive biomarkers of copper (Cu) (as copper chloride dihydrate), cadmium (Cd) (as cadmium acetate), lead (Pb) (as lead nitrate) and chromium (Cr) (as potassium dichromate) exposure in adult zebrafish, focusing on reactive oxygen species (ROS), SOD activity, lipid peroxidation and gene expression related to oxidative stress and inflammatory response. Furthermore, the survival rate decreased apparently by a concentration-dependent manner after Cu, Cr, Cd and Pb exposure, and we selected non-lethal concentrations 0.05 mg/L for Cu, 15 mg/L for Cr, 3 mg/L for Cd and 93.75μg/L for Pb to test the effect on the following biological indicators. Under non-lethal concentration, the four heavy metals have no apparent histological change in adult zebrafish gills. Similar trends in ROS production, MDA level and SOD activity were up-regulated by the four heavy metals, while MDA level responded more sensitive to Pb by time-dependent manner than the other three heavy metals. In addition, mRNA levels related to antioxidant system (SOD1, SOD2 and Nrf2) were up-regulated by non-lethal concentration Cu, Cr, Cd and Pb exposure. MDA level and SOD1 gene have a more delayed response to heavy metals. Genes related to immunotoxicity were increased significantly after heavy metals exposure at non-lethal concentrations. TNF-α and IL-1β gene have similar sensibility to the four heavy metals, while IL-8 gene was more responsive to Cr, Cd and Pb exposure at 48 h groups and IFN-γ gene showed more sensitivity to Cu at 48 h groups than the other heavy metals. In conclusion, the present works have suggested that the IFN-γ gene may applied as early sensitive biomarker to identify Cu-induced toxicity, while MDA content and IL-8 gene may use as early sensitive biomarkers for evaluating the risk of Pb exposure. Moreover, IL-8 and IFN-γ gene were more responsive to heavy metals, which may become early sensitive and potential biomarkers for evaluating inflammatory response induced by heavy metals. This work reinforces the concept of the usefulness of gene expression assays in the evaluation of chemicals effects and helps to establish a background data as well as contributes to evaluate early environmental risk for chemicals, even predicting toxicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessment of streambed sediment contamination by heavy metals: The case of the Gabes Catchment, South-eastern Tunisia

NASA Astrophysics Data System (ADS)

Dahri, Noura; Atoui, Abdelfattah; Ellouze, Manel; Abida, Habib

2018-04-01

This study deals with the assessment of the behaviour of seven heavy metals (Cd, Zn, Cu, Pb, Ni, Cr and As) in streambed sediments within the Gabes Catchment, located in South-eastern Tunisia. To understand the effect of intense human activities in the Gabes Basin on the quality of the environment, 22 sediment samples, spread all over the study basin, were taken and analyzed for heavy metals. Heavy metal concentrations were shown to vary in the following order: Zn > Pb > Cu > Cr > Ni > Cd > As. Sediment quality was assessed based on the evaluation of various indices. A total of 27% of the sampling stations are characterised by sediment Enrichment Factors (EF) exceeding 40, reflecting extremely severe pollution. This result was also confirmed by different indices, including Sediment Pollution Index (SPI), Pollution Load Index (PLI) and Geo-accumulation index. The calculation of Mean Effect Range-Median Quotient (M-ERM-Q) indicated that in stream discharge, all metals have a probability of 21% to be toxic. The ecological toxicity risk of heavy metals increases close to urban (traffic activity) and industrial activities (industrial complex of Gabes). Close to Gabes City, the situation and the degree of contamination that may be transferred into marine ecosystems is worrisome and requires immediate intervention.

Time Series Analysis of Heavy Metal Concentrations along the Watershed Gradient in Cameron Highlands: Geospatial Approaches

NASA Astrophysics Data System (ADS)

Haron, S. H.; Ismail, B. S.; Mispan, M. R.; Abd Rahman, N. F.; Khalid, K.; Rasid, M. Z. Abdul; Sidek, L. M.

2016-03-01

Heavy metal, particularly cadmium, lead, and arsenic, constitute a significant potential threat to human health. Some metals are extremely toxic to humans and the toxic heavy metals of greatest concern include cadmium, lead, and arsenic. The objective of the study conducted was to determine the accumulation and distribution status of heavy metal cadmium (Cd) in the sediment of Bertam River from September 2014 to February 2015 in the agricultural areas of Cameron Highlands, Malaysia. The sediment samples were collected randomly in three replicates from ten sampling points in the agricultural areas of Cameron Highlands. The heavy metals in the sediment were extracted using the wet acid method and the sample concentrations are then tested for metal concentrations by the spectrography method using Inductively Coupled Plasma (ICP) spectrography. Inverse distance weighting (IDW) was used to create a map of metal concentrations for a point on the polygon dataset spatial interpolation. There is an increasing trend of Cd from the upstream to downstream stations along Bertam River during the rainy season. The activity range of Cd is 0.07 to 2.83 µg/g during the rainy season, whereas, during the dry season, Cd activity ranged from 0.26-0.83µg/g.

The Ability of Bacterial Cocaine Esterase to Hydrolyze Cocaine Metabolites and Their Simultaneous Quantification Using High-Performance Liquid Chromatography-Tandem Mass Spectrometry

PubMed Central

Brim, Remy L.; Noon, Kathleen R.; Collins, Gregory T.; Nichols, Joseph; Narasimhan, Diwahar; Sunahara, Roger K.

2011-01-01

Cocaine toxicity is a widespread problem in the United States, responsible for more than 500,000 emergency department visits a year. There is currently no U.S. Food and Drug Administration-approved pharmacotherapy to directly treat cocaine toxicity. To this end, we have developed a mutant bacterial cocaine esterase (DM-CocE), which has been previously shown to rapidly hydrolyze cocaine into inert metabolites, preventing and reversing toxicity with limited immunogenic potential. Herein we describe the ability of DM-CocE to hydrolyze the active cocaine metabolites norcocaine and cocaethylene and its inability to hydrolyze benzoylecgonine. DM-CocE hydrolyzes norcocaine and cocaethylene with 58 and 45% of its catalytic efficiency for cocaine in vitro as measured by a spectrophotometric assay. We have developed a mass spectrometry method to simultaneously detect cocaine, benzoylecgonine, norcocaine, and ecgonine methyl ester to quantify the effect of DM-CocE on normal cocaine metabolism in vivo. DM-CocE administered to rats 10 min after a convulsant dose of cocaine alters the normal metabolism of cocaine, rapidly decreasing circulating levels of cocaine and norcocaine while increasing ecgonine methyl ester formation. Benzoylecgonine was not hydrolyzed in vivo, but circulating concentrations were reduced, suggesting that DM-CocE may bind and sequester this metabolite. These findings suggest that DM-CocE may reduce cocaine toxicity by eliminating active and toxic metabolites along with the parent cocaine molecule. PMID:21885621

Physical Aspects of Photodynamic Corneal Collagen Crosslinking

NASA Astrophysics Data System (ADS)

Kornfield, Julia

2012-02-01

Healthy vision depends on the stability of the shape of the cornea, which provides most of the lens power of the optical system of the eye. Diseases in which the cornea progressively undergoes irregular deformation over time (e.g., keratoconus) can be treated clinically by inducing additional protein-protein crosslinks using a photosensitizing drug and a tailored dose of light. Unfortunately, the treatment moving through clinical trials is toxic to cells in and on the cornea. A path to a safer treatment is offered by the nanostructure of the corneal stroma---reminiscent of a HEX phase in block copolymers with 30nm diameter collagen cylinders spaced 60nm center-to-center in a hydrogel matrix of proteoglycans and water. We show that using a photosensitizing drug that sequesters itself in the collagen fibrils can minimize the toxicity of therapeutic protein-protein cross-linking. Photorheology and transport measurements are used to quantify the parameters of a simple physical model that is useful for optimizing clinical protocols.

Molecular basis for disruption of E-cadherin adhesion by botulinum neurotoxin A complex.

PubMed

Lee, Kwangkook; Zhong, Xiaofen; Gu, Shenyan; Kruel, Anna Magdalena; Dorner, Martin B; Perry, Kay; Rummel, Andreas; Dong, Min; Jin, Rongsheng

2014-06-20

How botulinum neurotoxins (BoNTs) cross the host intestinal epithelial barrier in foodborne botulism is poorly understood. Here, we present the crystal structure of a clostridial hemagglutinin (HA) complex of serotype BoNT/A bound to the cell adhesion protein E-cadherin at 2.4 angstroms. The HA complex recognizes E-cadherin with high specificity involving extensive intermolecular interactions and also binds to carbohydrates on the cell surface. Binding of the HA complex sequesters E-cadherin in the monomeric state, compromising the E-cadherin-mediated intercellular barrier and facilitating paracellular absorption of BoNT/A. We reconstituted the complete 14-subunit BoNT/A complex using recombinantly produced components and demonstrated that abolishing either E-cadherin- or carbohydrate-binding of the HA complex drastically reduces oral toxicity of BoNT/A complex in vivo. Together, these studies establish the molecular mechanism of how HAs contribute to the oral toxicity of BoNT/A. Copyright © 2014, American Association for the Advancement of Science.

Sequestration of arsenic in ombrotrophic peatlands

NASA Astrophysics Data System (ADS)

Rothwell, James; Hudson-Edwards, Karen; Taylor, Kevin; Polya, David; Evans, Martin; Allott, Tim

2014-05-01

Peatlands can be important stores of arsenic but we are lacking spectroscopic evidence of the sequestration pathways of this toxic metalloid in peatland environments. This study reports on the solid-phase speciation of anthropogenically-derived arsenic in atmospherically contaminated peat from the Peak District National Park (UK). Surface and sub-surface peat samples were analysed by synchrotron X-ray absorption spectroscopy on B18 beamline at Diamond Light Source (UK). The results suggest that there are contrasting arsenic sequestration mechanisms in the peat. The bulk arsenic speciation results, in combination with strong arsenic-iron correlations at the surface, suggest that iron (hydr)oxides are key phases for the immobilisation of arsenic at the peat surface. In contrast, the deeper peat samples are dominated by arsenic sulphides (arsenopyrite, realgar and orpiment). Given that these peats receive inputs solely from the atmosphere, the presence of these sulphide phases suggests an in-situ authigenic formation. Redox oscillations in the peat due to a fluctuating water table and an abundant store of legacy sulphur from historic acid rain inputs may favour the precipitation of arsenic sequestering sulphides in sub-surface horizons. Oxidation-induced loss of these arsenic sequestering sulphur species by water table drawdown has important implications for the mobility of arsenic and the quality of waters draining peatlands.

Divergent biology of facultative heavy metal plants.

PubMed

Bothe, Hermann; Słomka, Aneta

2017-12-01

Among heavy metal plants (the metallophytes), facultative species can live both in soils contaminated by an excess of heavy metals and in non-affected sites. In contrast, obligate metallophytes are restricted to polluted areas. Metallophytes offer a fascinating biology, due to the fact that species have developed different strategies to cope with the adverse conditions of heavy metal soils. The literature distinguishes between hyperaccumulating, accumulating, tolerant and excluding metallophytes, but the borderline between these categories is blurred. Due to the fact that heavy metal soils are dry, nutrient limited and are not uniform but have a patchy distribution in many instances, drought-tolerant or low nutrient demanding species are often regarded as metallophytes in the literature. In only a few cases, the concentrations of heavy metals in soils are so toxic that only a few specifically adapted plants, the genuine metallophytes, can cope with these adverse soil conditions. Current molecular biological studies focus on the genetically amenable and hyperaccumulating Arabidopsis halleri and Noccaea (Thlaspi) caerulescens of the Brassicaceae. Armeria maritima ssp. halleri utilizes glands for the excretion of heavy metals and is, therefore, a heavy metal excluder. The two endemic zinc violets of Western Europe, Viola lutea ssp. calaminaria of the Aachen-Liège area and Viola lutea ssp. westfalica of the Pb-Cu-ditch of Blankenrode, Eastern Westphalia, as well as Viola tricolor ecotypes of Eastern Europe, keep their cells free of excess heavy metals by arbuscular mycorrhizal fungi which bind heavy metals. The Caryophyllaceae, Silene vulgaris f. humilis and Minuartia verna, apparently discard leaves when overloaded with heavy metals. All Central European metallophytes have close relatives that grow in areas outside of heavy metal soils, mainly in the Alps, and have, therefore, been considered as relicts of the glacial epoch in the past. However, the current literature favours the idea that hyperaccumulation of heavy metals serves plants as deterrent against attack by feeding animals (termed elemental defense hypothesis). The capability to hyperaccumulate heavy metals in A. halleri and N. caerulescens is achieved by duplications and alterations of the cis-regulatory properties of genes coding for heavy metal transporting/excreting proteins. Several metallophytes have developed ecotypes with a varying content of such heavy metal transporters as an adaption to the specific toxicity of a heavy metal site. Copyright © 2017 Elsevier GmbH. All rights reserved.

Differential contributions of Caenorhabditis elegans histone deacetylases to huntingtin polyglutamine toxicity.

PubMed

Bates, Emily A; Victor, Martin; Jones, Adriana K; Shi, Yang; Hart, Anne C

2006-03-08

Expansion of a polyglutamine tract in the huntingtin protein causes neuronal degeneration and death in Huntington's disease patients, but the molecular mechanisms underlying polyglutamine-mediated cell death remain unclear. Previous studies suggest that expanded polyglutamine tracts alter transcription by sequestering glutamine rich transcriptional regulatory proteins, thereby perturbing their function. We tested this hypothesis in Caenorhabditis elegans neurons expressing a human huntingtin fragment with an expanded polyglutamine tract (Htn-Q150). Loss of function alleles and RNA interference (RNAi) were used to examine contributions of C. elegans cAMP response element-binding protein (CREB), CREB binding protein (CBP), and histone deacetylases (HDACs) to polyglutamine-induced neurodegeneration. Deletion of CREB (crh-1) or loss of one copy of CBP (cbp-1) enhanced polyglutamine toxicity in C. elegans neurons. Loss of function alleles and RNAi were then used to systematically reduce function of each C. elegans HDAC. Generally, knockdown of individual C. elegans HDACs enhanced Htn-Q150 toxicity, but knockdown of C. elegans hda-3 suppressed toxicity. Neuronal expression of hda-3 restored Htn-Q150 toxicity and suggested that C. elegans HDAC3 (HDA-3) acts within neurons to promote degeneration in response to Htn-Q150. Genetic epistasis experiments suggested that HDA-3 and CRH-1 (C. elegans CREB homolog) directly oppose each other in regulating transcription of genes involved in polyglutamine toxicity. hda-3 loss of function failed to suppress increased neurodegeneration in hda-1/+;Htn-Q150 animals, indicating that HDA-1 and HDA-3 have different targets with opposing effects on polyglutamine toxicity. Our results suggest that polyglutamine expansions perturb transcription of CREB/CBP targets and that specific targeting of HDACs will be useful in reducing associated neurodegeneration.

The San Francisco Bay - Delta Wastewater and Residual Solids Management Study. Volume III. Technical Appendix. Wastewater Residual Solids Management Study

DTIC Science & Technology

1972-08-01

of public health hazards and may alter reuse approaches to de -emphasize the fertilizer uses of these sludges because of the heavy metals involved...materials are removed with organic sludges, or lime sludges where that process is used. Toxic solids would typically include phenols and heavy metals , 80...solids would typically include phenols and heavy metals , 80 percent and 40 percent respectively being removable with the organic sludges. - 8

Biochar modulates heavy metal toxicity and improves microbial carbon use efficiency in soil.

PubMed

Xu, Yilu; Seshadri, Balaji; Sarkar, Binoy; Wang, Hailong; Rumpel, Cornelia; Sparks, Donald; Farrell, Mark; Hall, Tony; Yang, Xiaodong; Bolan, Nanthi

2018-04-15

Soil organic carbon is essential to improve soil fertility and ecosystem functioning. Soil microorganisms contribute significantly to the carbon transformation and immobilisation processes. However, microorganisms are sensitive to environmental stresses such as heavy metals. Applying amendments, such as biochar, to contaminated soils can alleviate the metal toxicity and add carbon inputs. In this study, Cd and Pb spiked soils treated with macadamia nutshell biochar (5% w/w) were monitored during a 49days incubation period. Microbial phospholipid fatty acids (PLFAs) were extracted and analysed as biomarkers in order to identify the microbial community composition. Soil properties, metal bioavailability, microbial respiration, and microbial biomass carbon were measured after the incubation period. Microbial carbon use efficiency (CUE) was calculated from the ratio of carbon incorporated into microbial biomass to the carbon mineralised. Total PLFA concentration decreased to a greater extent in metal contaminated soils than uncontaminated soils. Microbial CUE also decreased due to metal toxicity. However, biochar addition alleviated the metal toxicity, and increased total PLFA concentration. Both microbial respiration and biomass carbon increased due to biochar application, and CUE was significantly (p<0.01) higher in biochar treated soils than untreated soils. Heavy metals reduced the microbial carbon sequestration in contaminated soils by negatively influencing the CUE. The improvement of CUE through biochar addition in the contaminated soils could be attributed to the decrease in metal bioavailability, thereby mitigating the biotoxicity to soil microorganisms. Copyright © 2017 Elsevier B.V. All rights reserved.

Influence of temperature and nutrient strength on the susceptibility of Saccharomyces cerevisiae to heavy metals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, T.; Lee, L.W.; Chang, T.H.

1992-09-01

Saccharomyces cerevisiae is not only a key microorganism in brewing or fermentation processes, it has also been employed for monitoring aquatic pollutants. The major advantage of using Saccharomyces cerevisiae as a bioassay system is that this yeast can be easily obtained as dry pellets from commercial sources at low cost. In addition to its economical aspect, Saccharomyces cerevisiae, like other microorganisms, is easy to handle, grows rapidly, and provides a large number of homogeneous individuals for utilization in toxicity tests. Although cell growth, cell viability, electron transport and mitochondrial respiration of Saccharomyces cerevisiaes have all been selected as parameters formore » toxicity assessment, measuring cell growth by absorbance is by farm the most convenient and rapid method when large amounts of water samples are to be tested. Mochida et al. (1988), however, reported that Saccharomyces cerevisiae was five to ten times less sensitive than cell culture systems to cadmium, mercury and nickel, when cell growth of both systems was monitored. This relative insensitivity to heavy metals might handicap the practical use of this yeast strain for bioassays. Since previous studies indicated that the susceptibility of microorganisms to environmental toxicants can be influenced by incubation temperature and nutrient strength, we attempted to examine the effect of incubation temperature and nutrient strength on the susceptibility of Saccharomyces cerevisiae to heavy metals in order to obtain the optimum bioassay sensitivity. In this study, we used cadmium and mercury as model toxicants. 9 refs., 2 figs., 1 tab.« less

Nitric oxide overcomes Cd and Cu toxicity in in vitro-grown tobacco plants through increasing contents and activities of rubisco and rubisco activase.

PubMed

Khairy, Alaaldin Idris H; Oh, Mi Jeong; Lee, Seung Min; Kim, Da Som; Roh, Kwang Soo

2016-06-01

Toxic heavy metals such as cadmium (Cd) and copper (Cu) are global problems that are a growing threat to the environment. Despite some heavy metals are required for plant growth and development, others are considered toxic elements and do not play any known physiological role in plant cells. Elevated doses of Cd or Cu cause toxicity in plants and generate damages due to the stress condition and eventually cause a significant reduction in quantity and quality of crop plants. The nitric oxide (NO) donor sodium nitroprusside (SNP) is reported to alleviate the toxicity of some heavy metals like Cd and Cu. In the current study, the role of NO in alleviating stresses of Cd and Cu was investigated in in vitro -grown tobacco ( Nicotiana tabacum ) Based on plant growth, total chlorophyll contents, contents and activities of rubisco and rubisco activase. According to the results of this study, the growth and total chlorophyll contents of Cd/Cu stressed plants were hugely decreased in the absence of SNP, while the supplementation of SNP resulted in a significant increase of both fresh weight and total chlorophyll contents. Remarkable reductions of Rubisco and rubisco activase contents and activities were observed in Cd and Cu-induced plants. SNP supplementation showed the highest contents and activities of rubisco and rubisco activase compared to the control and Cu/Cd-stressed plants. Taken together, our findings suggest that SNP could play a protective role in regulation of plant responses to abiotic stresses such as Cd and Cu by enhancing Rubisco and Rubisco activase.

Speciation and Toxic Emissions from On road Vehicles, and Particulate Matter Emissions from Light-Duty Gasoline Vehicles in MOVES201X

EPA Science Inventory

Updated methane, non-methane organic gas, and volatile organic compound calculations based on speciation data. Updated speciation and toxic emission rates for new model year 2010 and later heavy-duty diesel engines. Updated particulate matter emission rates for 2004 and later mod...

Porphyrinuria in childhood autistic disorder: Implications for environmental toxicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nataf, Robert; Skorupka, Corinne; Amet, Lorene

To address a possible environmental contribution to autism, we carried out a retrospective study on urinary porphyrin levels, a biomarker of environmental toxicity, in 269 children with neurodevelopmental and related disorders referred to a Paris clinic (2002-2004), including 106 with autistic disorder. Urinary porphyrin levels determined by high-performance liquid chromatography were compared between diagnostic groups including internal and external control groups. Coproporphyrin levels were elevated in children with autistic disorder relative to control groups. Elevation was maintained on normalization for age or to a control heme pathway metabolite (uroporphyrin) in the same samples. The elevation was significant (P < 0.001).more » Porphyrin levels were unchanged in Asperger's disorder, distinguishing it from autistic disorder. The atypical molecule precoproporphyrin, a specific indicator of heavy metal toxicity, was also elevated in autistic disorder (P < 0.001) but not significantly in Asperger's. A subgroup with autistic disorder was treated with oral dimercaptosuccinic acid (DMSA) with a view to heavy metal removal. Following DMSA there was a significant (P = 0.002) drop in urinary porphyrin excretion. These data implicate environmental toxicity in childhood autistic disorder.« less

Porphyrinuria in childhood autistic disorder: implications for environmental toxicity.

PubMed

Nataf, Robert; Skorupka, Corinne; Amet, Lorene; Lam, Alain; Springbett, Anthea; Lathe, Richard

2006-07-15

To address a possible environmental contribution to autism, we carried out a retrospective study on urinary porphyrin levels, a biomarker of environmental toxicity, in 269 children with neurodevelopmental and related disorders referred to a Paris clinic (2002-2004), including 106 with autistic disorder. Urinary porphyrin levels determined by high-performance liquid chromatography were compared between diagnostic groups including internal and external control groups. Coproporphyrin levels were elevated in children with autistic disorder relative to control groups. Elevation was maintained on normalization for age or to a control heme pathway metabolite (uroporphyrin) in the same samples. The elevation was significant (P < 0.001). Porphyrin levels were unchanged in Asperger's disorder, distinguishing it from autistic disorder. The atypical molecule precoproporphyrin, a specific indicator of heavy metal toxicity, was also elevated in autistic disorder (P < 0.001) but not significantly in Asperger's. A subgroup with autistic disorder was treated with oral dimercaptosuccinic acid (DMSA) with a view to heavy metal removal. Following DMSA there was a significant (P = 0.002) drop in urinary porphyrin excretion. These data implicate environmental toxicity in childhood autistic disorder.

Effect of stress at dosing on organophosphate and heavy metal toxicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jortner, Bernard S.

2008-11-15

This paper reviews recent studies assessing the effect of well-defined, severe, transient stress at dosing on two classical models of toxicity. These are the acute (anticholinesterase) toxicity seen following exposure to the organophosphate insecticide chlorpyrifos, and the nephrotoxicity elicited by the heavy metal depleted uranium, in rats. Stress was induced by periods of restraint and forced swimming in days to weeks preceding toxicant exposure. Forced swimming was far more stressful, as measured by marked, if transient, elevation of plasma corticosterone. This form of stress was administered immediately prior to administration of chlorpyrifos or depleted uranium. Chlorpyrifos (single 60 mg/kg subcutaneously)more » elicited marked inhibition of brain acetylcholinesterase 4-day post-dosing. Depleted uranium (single intramuscular doses of 0.1, 0.3 or 1.0 mg/kg uranium) elicited dose-dependent increase in kidney concentration of the metal, with associated injury to proximal tubular epithelium and increases in serum blood urea nitrogen and creatinine during the 30-day post-dosing period. Stress at dosing had no effect on these toxicologic endpoints.« less

Distribution, bioavailability, and leachability of heavy metals in soil particle size fractions of urban soils (northeastern China).

PubMed

Yutong, Zong; Qing, Xiao; Shenggao, Lu

2016-07-01

This study examines the distribution, mobility, and potential environmental risks of heavy metals in various particle size fractions of urban soils. Representative urban topsoils (ten) collected from Anshan, Liaoning (northeastern China), were separated into six particle size fractions and their heavy metal contents (Cr, Cu, Cd, Pb, and Zn) were determined. The bioaccessibility and leachability of heavy metals in particle size fractions were evaluated using the toxicity characteristic leaching procedure (TCLP) and ethylenediaminetetraacetic acid (EDTA) extraction, respectively. The results indicated that the contents of five heavy metals (Cd, Cr, Cu, Pb and Zn) in the size fractions increased with the decrease of particle size. The clay fraction of <2 μm had the highest content of heavy metals, indicating that the clay fraction was polluted by heavy metals more seriously than the other size fractions in urban topsoils. Cr also concentrated in the coarse fraction of 2000-1000 μm, indicating a lithogenic contribution. However, the dominant size fraction responsible for heavy metal accumulation appeared to belong to particle fraction of 50-2 μm. The lowest distribution factors (DFs) of heavy metals were recorded in the 2000- to 1000-μm size fraction, while the highest in the clay fraction. The DFs of heavy metals in the clay fraction followed Zn (3.22) > Cu (2.84) > Pb (2.61) > Cr (2.19) > Cd (2.05). The enrichment factor suggested that the enrichment degree of heavy metal increased with the decrease of the particle size, especially for Cd and Zn. The TCLP- and EDTA-extractable concentrations of heavy metals in the clay fraction were relatively higher than those in coarse particles. Cd bioavailability was higher in the clay fraction than in other fractions or whole soils. In contrast, Cr exhibits similar bioaccessibilities in the six size fractions of soils. The results suggested that fine particles were the main sources of potentially toxic metals in urban soils. The variation of heavy metals in various size fractions should be taken into account in environment assessments.

Hydrometallurgical recovery of heavy metals from low grade automobile shredder residue (ASR): An application of advanced Fenton process (AFP).

PubMed

Singh, Jiwan; Lee, Byeong-Kyu

2015-09-15

To investigate the leaching and recovery of heavy metals from low-grade automobile shredder residue (ASR), the effects of nitric acid (HNO3) and hydrogen peroxide (H2O2) concentrations, liquid/solid (L/S) ratio, leaching temperature and ASR particle size fractions on the heavy metal leaching rate were determined. The heavy metals were recovered by fractional precipitation and advanced Fenton process (AFP) at different pHs. The toxicity characteristic leaching procedure (TCLP) test was also performed in the residue remaining after heavy metal leaching to evaluate the potential toxicity of ASR. The heavy metal leaching efficiency was increased with increasing HNO3 and H2O2 concentrations, L/S ratio and temperature. The heavy metal leaching efficiencies were maximized in the lowest ASR size fraction at 303 K and L/S ratio of 100 mL/g. The kinetic study showed that the metal leaching was best represented by a second-order reaction model, with a value of R(2) > 0.99 for all selected heavy metals. The determined activation energy (kJ/mol) was 21.61, 17.10, 12.15, 34.50, 13.07 and 11.45 for Zn, Fe, Ni, Pb, Cd and Cr, respectively. In the final residue, the concentrations of Cd, Cr and Pb were under their threshold limits in all ASR size fractions. Hydrometallurgical metal recovery was greatly increased by AFP up to 99.96% for Zn, 99.97% for Fe, 95.62% for Ni, 99.62% for Pb, 94.11% for Cd and 96.79% for Cr. AFP is highly recommended for the recovery of leached metals from solution even at low concentrations. Copyright © 2015 Elsevier Ltd. All rights reserved.

Addition of organic amendments contributes to C sequestration in trace element contaminated soils.

NASA Astrophysics Data System (ADS)

del Mar Montiel Rozas, María; Panettier, Marco; Madejón Rodríguez, Paula; Madejón Rodríguez, Engracia

2015-04-01

Nowadays, the study of global C cycle and the different natural sinks of C have become especially important in a climate change context. Fluxes of C have been modified by anthropogenic activities and, presently, the global objective is the decrease of net CO2 emission. For this purpose, many studies are being conducted at local level for evaluate different C sequestration strategies. These techniques must be, in addition to safe in the long term, environmentally friendly. Restoration of contaminated and degraded areas is considered as a strategy for SOC sequestration. Our study has been carried out in the Guadiamar Green Corridor (Seville, Spain) affected by the Aznalcóllar mining accident. This accident occurred 16 years ago, due to the failure of the tailing dam which contained 4-5 million m3 of toxic tailings (slurry and acid water).The affected soils had a layer of toxic sludge containing heavy metals as As, Cd, Cu, Pb and Zn. Restoration techniques began to be applied just after the accident, including the removal of the toxic sludge and a variable layer of topsoil (10-30 cm) from the surface. In a second phase, in a specific area (experimental area) of the Green Corridor the addition of organic amendments (Biosolid compost (BC) and Leonardite (LE), a low grade coal rich in humic acids) was carried out to increase pH, organic matter and fertility in a soil which lost its richest layer during the clean-up operation. In our experimental area, half of the plots (A) received amendments for four years (2002, 2003, 2006 and 2007) whereas the other half (B) received amendments only for two years (2002-2003). To compare, plots without amendments were also established. Net balance of C was carried out using values of Water Soluble Carbon (WSC) and Total Organic Carbon (TOC) for three years (2012, 2013 and 2015). To eliminate artificial changes carried out in the plots, amendment addition and withdrawal of biomass were taken into account to calculate balance of kg TOC ha ¯¹. Thus, results revealed the effect of amendments. Values of net balance show an increase in C sequestered in amended plots. The retention of carbon in soluble and total forms was reflected in the increase in time. According to the results, application of leonardite (a more stabilized amendment) seems to entail a greater retention of carbon in soil than in the case of biosolid compost. Restoration strategies have multiple benefits for the ecosystem. In our case, the use of organic amendments decreased trace element toxicity, improved soil structure and microbial communities, and contribute to retain C in terrestrial ecosystems.

Heavy Metals Induce Iron Deficiency Responses at Different Hierarchic and Regulatory Levels1[OPEN

PubMed Central

2017-01-01

In plants, the excess of several heavy metals mimics iron (Fe) deficiency-induced chlorosis, indicating a disturbance in Fe homeostasis. To examine the level at which heavy metals interfere with Fe deficiency responses, we carried out an in-depth characterization of Fe-related physiological, regulatory, and morphological responses in Arabidopsis (Arabidopsis thaliana) exposed to heavy metals. Enhanced zinc (Zn) uptake closely mimicked Fe deficiency by leading to low chlorophyll but high ferric-chelate reductase activity and coumarin release. These responses were not caused by Zn-inhibited Fe uptake via IRON-REGULATED TRANSPORTER (IRT1). Instead, Zn simulated the transcriptional response of typical Fe-regulated genes, indicating that Zn affects Fe homeostasis at the level of Fe sensing. Excess supplies of cobalt and nickel altered root traits in a different way from Fe deficiency, inducing only transient Fe deficiency responses, which were characterized by a lack of induction of the ethylene pathway. Cadmium showed a rather inconsistent influence on Fe deficiency responses at multiple levels. By contrast, manganese evoked weak Fe deficiency responses in wild-type plants but strongly exacerbated chlorosis in irt1 plants, indicating that manganese antagonized Fe mainly at the level of transport. These results show that the investigated heavy metals modulate Fe deficiency responses at different hierarchic and regulatory levels and that the interaction of metals with physiological and morphological Fe deficiency responses is uncoupled. Thus, this study not only emphasizes the importance of assessing heavy metal toxicities at multiple levels but also provides a new perspective on how Fe deficiency contributes to the toxic action of individual heavy metals. PMID:28500270

[Research advances in heavy metals pollution ecology of diatom].

PubMed

Ding, Teng-Da; Ni, Wan-Min; Zhang, Jian-Ying

2012-03-01

Diatom, due to its high sensitivity to environmental change, is one of the bio-indicators of aquatic ecosystem health, and some typical diatom species have been applied to indicate the heavy metals pollution of water body. With the focus on the surface water heavy metals pollution, this paper reviewed the research advances in the toxic effect of heavy metals pollution on diatom, biosorption and bioaccumulation of heavy metals by diatom, ecological adaptation mechanisms of diatom to heavy metals pollution, and roles of diatom as bio-indicator and in ecological restoration of heavy metals pollution. The growth tendency of diatom and the morphological change of frustule under heavy metals pollution as well as the differences in heavy metals biosorption and bioaccumulation by diatom, the ecological adaptation mechanisms of diatom on heavy metals surface complexation and ion exchange, and the roles of diatom as bio-indicator and in ecological restoration of heavy metals polluted water body were also discussed. This review could provide scientific evidences for the prevention of aquatic ecosystems heavy metals pollution and related early warning techniques.

Toxicity of nanomaterials

PubMed Central

Sharifi, Shahriar; Behzadi, Shahed; Laurent, Sophie; Forrest, M. Laird; Stroeve, Pieter

2015-01-01

Nanoscience has matured significantly during the last decade as it has transitioned from bench top science to applied technology. Presently, nanomaterials are used in a wide variety of commercial products such as electronic components, sports equipment, sun creams and biomedical applications. There are few studies of the long-term consequences of nanoparticles on human health, but governmental agencies, including the United States National Institute for Occupational Safety and Health and Japan’s Ministry of Health, have recently raised the question of whether seemingly innocuous materials such as carbon-based nanotubes should be treated with the same caution afforded known carcinogens such as asbestos. Since nanomaterials are increasing a part of everyday consumer products, manufacturing processes, and medical products, it is imperative that both workers and end-users be protected from inhalation of potentially toxic NPs. It also suggests that NPs may need to be sequestered into products so that the NPs are not released into the atmosphere during the product’s life or during recycling. Further, non-inhalation routes of NP absorption, including dermal and medical injectables, must be studied in order to understand possible toxic effects. Fewer studies to date have addressed whether the body can eventually eliminate nanomaterials to prevent particle build-up in tissues or organs. This critical review discusses the biophysicochemical properties of various nanomaterials with emphasis on currently available toxicology data and methodologies for evaluating nanoparticle toxicity. PMID:22170510

Transfers and transformations of zinc in flow-through wetland microcosms.

PubMed

Gillespie, W B; Hawkins, W B; Rodgers, J H; Cano, M L; Dorn, P B

1999-06-01

Two microcosm-scale wetlands (570-liter containers) were integratively designed and constructed to investigate transfers and transformations of zinc associated with an aqueous matrix, and to provide future design parameters for pilot-scale constructed wetlands. The fundamental design of these wetland microcosms was based on biogeochemical principles regulating fate and transformations of zinc (pH, redox, etc.). Each wetland consisted of a 45-cm hydrosoil depth inundated with 25 cm of water, and planted with Scirpus californicus. Zinc ( approximately 2 mg/liter) as ZnCl2 was amended to each wetland for 62 days. Individual wetland hydraulic retention times (HRT) were approximately 24 h. Total recoverable zinc was measured daily in microcosm inflow and outflows, and zinc concentrations in hydrosoil and S. californicus tissue were measured pre- and post-treatment. Ceriodaphnia dubia and Pimephales promelas7-day aqueous toxicity tests were performed on wetland inflows and outflows, and Hyalella azteca whole sediment toxicity tests (10-day) were performed pre- and post-treatment. Approximately 75% of total recoverable zinc was transferred from the water column. Toxicity decreased from inflow to outflow based on 7-day C. dubia tests, and survival of H. azteca in hydrosoil was >80%. Data illustrate the ability of integratively designed wetlands to transfer and sequester zinc from the water column while concomitantly decreasing associated toxicity. Copyright 1999 Academic Press.

Metal-metal interaction mediates the iron induction of Drosophila MtnB

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiang, Wenjia; Huang, Yunpeng; Wan, Zhihui

Metallothionein (MT) protein families are a class of small and universal proteins rich in cysteine residues. They are synthesized in response to heavy metal stresses to sequester the toxic ions by metal-thiolate bridges. Five MT family members, namely MtnA, MtnB, MtnC, MtnD and MtnE, have been discovered and identified in Drosophila. These five isoforms of MTs are regulated by metal responsive transcription factor dMTF-1 and play differentiated but overlapping roles in detoxification of metal ions. Previous researches have shown that Drosophila MtnB responds to copper (Cu), cadmium (Cd) and zinc (Zn). Interestingly in this study we found that Drosophila MtnBmore » expression also responds to elevated iron levels in the diet. Further investigations revealed that MtnB plays limited roles in iron detoxification, and the direct binding of MtnB to ferrous iron in vitro is also weak. The induction of MtnB by iron turns out to be mediated by iron interference of other metals, because EDTA at even a partial concentration of that of iron can suppress this induction. Indeed, in the presence of iron, zinc homeostasis is altered, as reflected by expression changes of zinc transporters dZIP1 and dZnT1. Thus, iron-mediated MtnB induction appears resulting from interrupted homeostasis of other metals such as zinc, which in turns induced MtnB expression. Metal-metal interaction may more widely exist than we expected. - Highlights: • Metallothionein B expression is regulated by iron in Drosophila melanogaster. • MtnB has limited physiological roles in iron detoxification. • Binding affinity of MtnB to iron is weak in vitro. • Induction of Drosophila MtnB by iron is mediated indirectly through metal-metal interaction.« less

Enhanced cadmium accumulation and tolerance in transgenic tobacco overexpressing rice metal tolerance protein gene OsMTP1 is promising for phytoremediation.

PubMed

Das, Natasha; Bhattacharya, Surajit; Maiti, Mrinal K

2016-08-01

One of the most grievous heavy metal pollutants in the environment is cadmium (Cd), which is not only responsible for the crop yield loss owing to its phytotoxicity, but also for the human health hazards as the toxic elements usually accumulate in the consumable parts of crop plants. In the present study, we aimed to isolate and functionally characterize the OsMTP1 gene from indica rice (Oryza sativa L. cv. IR64) to study its potential application for efficient phytoremediation of Cd. The 1257 bp coding DNA sequence (CDS) of OsMTP1 encodes a ∼46 kDa protein belonging to the cation diffusion facilitator (CDF) or metal tolerance/transport protein (MTP) family. The OsMTP1 transcript in rice plant was found to respond during external Cd stress. Heterologous expression of OsMTP1 in tobacco resulted in the reduction of Cd stress-induced phytotoxic effects, including growth inhibition, lipid peroxidation, and cell death. Compared to untransformed control, the transgenic tobacco plants showed enhanced vacuolar thiol content, indicating vacuolar localization of the sequestered Cd. The transgenic tobacco plants exhibited significantly higher biomass growth (2.2-2.8-folds) and hyperaccumulation of Cd (1.96-2.22-folds) compared to untransformed control under Cd exposure. The transgenic plants also showed moderate tolerance and accumulation of arsenic (As) upon exogenous As stress, signifying broad substrate specificity of OsMTP1. Together, findings of our research suggest that the transgenic tobacco plants overexpressing OsMTP1 with its hyperaccumulating activity and increased growth rate could be useful for future phytoremediation applications to clean up the Cd-contaminated soil. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Sulfur vesicles from Thermococcales: A possible role in sulfur detoxifying mechanisms

PubMed Central

Gorlas, A.; Marguet, E.; Gill, S.; Geslin, C.; Guigner, J.-M.; Guyot, F.; Forterre, P.

2015-01-01

The euryarchaeon Thermococcus prieurii inhabits deep-sea hydrothermal vents, one of the most extreme environments on Earth, which is reduced and enriched with heavy metals. Transmission electron microscopy and cryo-electron microscopy imaging of T. prieurii revealed the production of a plethora of diverse membrane vesicles (MVs) (from 50 nm to 400 nm), as is the case for other Thermococcales. T. prieurii also produces particularly long nanopods/nanotubes, some of them containing more than 35 vesicles encased in a S-layer coat. Notably, cryo-electron microscopy of T. prieurii cells revealed the presence of numerous intracellular dark vesicles that bud from the host cells via interaction with the cytoplasmic membrane. These dark vesicles are exclusively found in conjunction with T. prieurii cells and never observed in the purified membrane vesicles preparations. Energy-Dispersive-X-Ray analyses revealed that these dark vesicles are filled with sulfur. Furthermore, the presence of these sulfur vesicles (SVs) is exclusively observed when elemental sulfur was added into the growth medium. In this report, we suggest that these atypical vesicles sequester the excess sulfur not used for growth, thus preventing the accumulation of toxic levels of sulfur in the host's cytoplasm. These SVs transport elemental sulfur out of the cell where they are rapidly degraded. Intriguingly, closely related archaeal species, Thermococcus nautili and Thermococcus kodakaraensis, show some differences about the production of sulfur vesicles. Whereas T. kodakaraensis produces less sulfur vesicles than T. prieurii, T. nautili does not produce such sulfur vesicles, suggesting that Thermococcales species exhibit significant differences in their sulfur metabolic pathways. PMID:26234734

Identification of compounds in heavy fuel oil that are chronically toxic to rainbow trout embryos by effects-driven chemical fractionation.

PubMed

Adams, Julie; Bornstein, Jason M; Munno, Keenan; Hollebone, Bruce; King, Thomas; Brown, R Stephen; Hodson, Peter V

2014-04-01

The present study isolated and identified compounds in heavy fuel oil 7102 (HFO 7102) that are bioavailable and chronically toxic to rainbow trout embryos (Oncorhynchus mykiss). An effects-driven chemical fractionation combined the chemical separation of oil with toxicity testing and chemical analyses of each fraction to identify the major classes of compounds associated with embryo toxicity. Toxicity was assessed with 2 exposure methods, a high-energy chemical dispersion of oil in water, which included oil droplets in test solutions, and water accommodated fractions which were produced by oiled gravel desorption columns, and which did not contain visible oil droplets. Fractions of HFO with high concentrations of naphthalenes, alkanes, asphaltenes, and resins were nontoxic to embryos over the range of concentrations tested. In contrast, fractions enriched with 3- to 4-ringed alkyl polycyclic aromatic hydrocarbons (PAHs) were embryotoxic, consistent with published studies of crude oils and individual alkyl PAHs. The rank order of fraction toxicity did not vary between the exposure methods and was consistent with their PAH content; fractions with higher-molecular weight alkyl PAHs were the most toxic. Exposure of juvenile trout to most fractions of HFO induced higher activities of cytochrome P450 enzymes, with a rank order of potency that varied with exposure method and differed somewhat from that of embryotoxicity. Induction reflected the bioavailability of PAHs but did not accurately predict embryotoxicity. © 2013 SETAC.

Iron Balance and the Role of Hepcidin in Chronic Kidney Disease

PubMed Central

Ganz, Tomas; Nemeth, Elizabeta

2016-01-01

Summary The hepatic iron-regulatory hormone hepcidin and its receptor, the cellular iron exporter ferroportin, constitute a feedback-regulated mechanism that maintains adequate plasma concentrations of iron-transferrin for erythropoiesis and other functions, ensures sufficient iron stores, and avoids iron toxicity and iron-dependent microbial pathogenesis. In chronic kidney disease, inflammation and impaired renal clearance increase plasma hepcidin, inhibiting duodenal iron absorption and sequestering iron in macrophages. These effects of hepcidin can cause systemic iron deficiency, decreased availability of iron for erythropoiesis, and resistance to endogenous and exogenous erythropoietin. Together with impaired renal production of erythropoietin, hepcidin-mediated iron restriction contributes to anemia of chronic kidney disease. PMID:27236128

Effects of heavy metals on benthic macroinvertebrate communities in New Zealand streams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hickey, C.W.; Clements, W.H.

1998-11-01

The authors performed chemical analyses of heavy metals in water and periphyton, toxicity tests with Daphnia magna and an indigenous mayfly (Deleatidium sp.), and field surveys of benthic macroinvertebrates to estimate the degree of metal pollution in three catchments in the Coromandel Peninsula of New Zealand. Good agreement was found between toxicity tests and measures of benthic community structure, particularly at stations with the highest metal levels. Responses of benthic communities at stations with low or moderate levels of metal contamination were variable and were probably confounded by factors other than heavy metals. Effects of heavy metals on benthic communitiesmore » in New Zealand streams were similar to those reported for metal-polluted streams in North America and Europe, suggesting that responses to metal contamination are predictable. Abundance and species richness of mayflies, number of taxa in the orders Ephemeroptera, Plecoptera, and Trichoptera, and total taxonomic richness were the best indicators of heavy metals in New Zealand streams. In contrast, the quantitative macroinvertebrate community index (QMCI), a biotic index proposed for assessing effects of organic enrichment in New Zealand streams, could not distinguish between reference and metal-polluted streams. The poor performance of the QMCI was primarily due to incorrect tolerance scores for some taxa to heavy metals. Because of concerns regarding the subjective assignment of tolerance values to species, the authors recommend that tolerance values for dominant species in New Zealand streams should be verified experimentally in stream microcosms.« less

Effect of Nano-Al2O3 on the Toxicity and Oxidative Stress of Copper towards Scenedesmus obliquus

PubMed Central

Li, Xiaomin; Zhou, Suyang; Fan, Wenhong

2016-01-01

Nano-Al2O3 has been widely used in various industries; unfortunately, it can be released into the aquatic environment. Although nano-Al2O3 is believed to be of low toxicity, it can interact with other pollutants in water, such as heavy metals. However, the interactions between nano-Al2O3 and heavy metals as well as the effect of nano-Al2O3 on the toxicity of the metals have been rarely investigated. The current study investigated copper toxicity in the presence of nano-Al2O3 towards Scenedesmus obliquus. Superoxide dismutase activity and concentration of glutathione and malondialdehyde in cells were determined in order to quantify oxidative stress in this study. Results showed that the presence of nano-Al2O3 reduced the toxicity of Cu towards S. obliquus. The existence of nano-Al2O3 decreased the growth inhibition of S. obliquus. The accumulation of copper and the level of oxidative stress in algae were reduced in the presence of nano-Al2O3. Furthermore, lower copper accumulation was the main factor that mitigated copper toxicity with the addition of nano-Al2O3. The decreased copper uptake could be attributed to the adsorption of copper onto nanoparticles and the subsequent decrease of available copper in water. PMID:27294942

Influence of complexation with chloride on the responses of a lux-marked bacteria bioassay to cadmium, copper, lead, and mercury

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarin, C.; Hall, J.M.; Cotter-Howells, J.

2000-02-01

The toxicity of a heavy metal in solution to a microorganism depends not only on its concentration but also on pH and the concentrations of any aqueous complexing ligands in the microorganism's environment. This paper reports on the use of different inorganic resuscitation media and effect of the chloride ion, Cl{sup {minus}}, on the bioluminescence response of a bacterial biosensor, Escherichia coli HB101 (pUCD607), to four metals: Cd, Cu, Hg, and Pb. The toxicity tests were conducted at pH 4, using 0.1 M KNO{sub 3} as resuscitation medium and adding KCl to investigate effect of Cl{sup {minus}} concentration. The speciesmore » distributions of metals as a function of Cl{sup {minus}} concentration were calculated using GeoChem-PC. Resuscitation in 0.1 M KCl gave significantly higher light output than that in 0.1 M KNO{sub 3}, demonstrating that Cl{sup {minus}} ions increased the toxicity of Hg, apparently because of the formation of HgCl{sub 3}{sup {minus}}, and increased the toxicity of Pb because of PbCl{sup +} formation. The toxicity of Cu decreased at high Cl{sup {minus}} concentrations as free Cu{sup 2+} decreased, in accordance with the free ion model. Concentrations of Cl{sup {minus}} had no significant effect on the toxicity of Cd. This study clearly demonstrates that the chloro-complexes of some heavy metals can be toxic and, for Pb and Hg, more toxic than the free ion.« less

Recycling used palm oil and used engine oil to produce white bio oil, bio petroleum diesel and heavy fuel

NASA Astrophysics Data System (ADS)

Al-abbas, Mustafa Hamid; Ibrahim, Wan Aini Wan; Sanagi, Mohd. Marsin

2012-09-01

Recycling waste materials produced in our daily life is considered as an additional resource of a wide range of materials and it conserves the environment. Used engine oil and used cooking oil are two oils disposed off in large quantities as a by-product of our daily life. This study aims at providing white bio oil, bio petroleum diesel and heavy fuel from the disposed oils. Toxic organic materials suspected to be present in the used engine oil were separated using vacuum column chromatography to reduce the time needed for the separation process and to avoid solvent usage. The compounds separated were detected by gas chromatography-mass spectrometry (GC-MS) and found to contain toxic aromatic carboxylic acids. Used cooking oils (thermally cracked from usage) were collected and separated by vacuum column chromatography. White bio oil produced was examined by GC-MS. The white bio oil consists of non-toxic hydrocarbons and is found to be a good alternative to white mineral oil which is significantly used in food industry, cosmetics and drugs with the risk of containing polycyclic aromatic compounds which are carcinogenic and toxic. Different portions of the used cooking oil and used engine were mixed to produce several blends for use as heavy oil fuels. White bio oil was used to produce bio petroleum diesel by blending it with petroleum diesel and kerosene. The bio petroleum diesel produced passed the PETRONAS flash point and viscosity specification test. The heat of combustion of the two blends of heavy fuel produced was measured and one of the blends was burned to demonstrate its burning ability. Higher heat of combustion was obtained from the blend containing greater proportion of used engine oil. This study has provided a successful recycled alternative for white bio oil, bio petroleum fuel and diesel which can be an energy source.

SITE-SPECIFIC VALIDATION OF A CHRONIC TOXICITY TEST WITH THE AMPHIPOD HYALELLA AZTECA : AN INTEGRATED STUDY OF HEAVY METAL CONTAMINATED SEDIMENTS IN PEAK CREEK, VIRGINIA

EPA Science Inventory

We will measure the correspondence of endpoints from chronic toxicity tests with the amphipod, Hyalella azteca, to a series of in situ macrobenthic community endpoints, starting with those endpoints most similar to those monitored in the laboratory test, then expanding to include...

Heavy metal concentrations and toxicity in water and sediment from stormwater ponds and sedimentation tanks.

PubMed

Karlsson, Kristin; Viklander, Maria; Scholes, Lian; Revitt, Mike

2010-06-15

Sedimentation is a widely used technique in structural best management practices to remove pollutants from stormwater. However, concerns have been expressed about the environmental impacts that may be exerted by the trapped pollutants. This study has concentrated on stormwater ponds and sedimentation tanks and reports on the accumulated metal concentrations (Cd, Cr, Ni, Pb, and Zn) and the associated toxicity to the bacteria Vibrio fischeri. The metal concentrations are compared with guidelines and the toxicity results are assessed in relation to samples for which metal concentrations either exceed or conform to these values. The water phase metal concentrations were highest in the ponds whereas the sedimentation tanks exhibited a distinct decrease towards the outlet. However, none of the water samples demonstrated toxicity even though the concentrations of Cu, Pb, and Zn exceeded the threshold values for the compared guidelines. The facilities with higher traffic intensities had elevated sediment concentrations of Cr, Cu, Ni, and Zn which increased towards the outlet for the sedimentation tanks in agreement with the highest percentage of fine particles. The sediments in both treatment facilities exhibited the expected toxic responses in line with their affinity for heavy metals but the role of organic carbon content is highlighted. Copyright 2010 Elsevier B.V. All rights reserved.

Heavy metals detection using biosensor cells of a novel marine luminescent bacterium Vibrio sp. MM1 isolated from the Caspian Sea.

PubMed

Mohseni, Mojtaba; Abbaszadeh, Jaber; Maghool, Shima-Sadat; Chaichi, Mohammad-Javad

2018-02-01

Monitoring and assessing toxic materials which are being released into the environment along with wastewater is a growing concern in many industries. The current research describes a highly sensitive and rapid method for the detection of toxic concentrations of heavy metals in aquatic environments. Water samples were collected from southern coasts of the Caspian Sea followed by screening of luminescent bacteria. Phylogenetic analysis, including gene sequence of 16S rRNA, and biochemical tests were performed for identification of the isolate. Luminescence activity was tested and measured after treatment of the isolate with different concentrations of heavy metals and reported as EC 50 value for each metal. A luminous, gram negative bacterium with the shape of a curved rod was isolated from the Caspian Sea. Biochemical tests and 16S rRNA gene sequence analysis indicated that the isolate MM1 had more than 99% similarity to Vibrio campbellii. The novel isolate is able to emit high levels of light. Bioluminescence inhibitory assay showed that the Vibrio sp. MM1 had the highest sensitivity to zinc and the lowest sensitivity to cadmium; EC 50 values were 0.97mgl -1 and 14.54mgl -1 , respectively. The current research shows that even low concentrations of heavy metals can cause a detectable decline in luminescence activity of the novel bacterium Vibrio sp. MM1; hence, it makes a good choice for commercial kits for the purpose of monitoring toxic materials. Copyright © 2017 Elsevier Inc. All rights reserved.

Pollution, toxicity, and ecological risk of heavy metals in surface river sediments of a large basin undergoing rapid economic development.

PubMed

Tang, Wenzhong; Zhang, Chao; Zhao, Yu; Shan, Baoqing; Song, Zhixin

2017-05-01

A comprehensive and detailed investigation of heavy metal pollution, toxicity, and ecological risk assessment was conducted for the surface river sediments of the Haihe Basin in China based on 220 sampling sites selected in 2013. The average concentrations of Cr, Cu, Ni, Pb, and Zn in the sediments were 129 mg/kg, 63.4 mg/kg, 36.6 mg/kg, 50.0 mg/kg, and 202 mg/kg, respectively. As indicated by the geoaccumulation and pollution load indices, most surface river sediments of the Haihe Basin were contaminated with the investigated metals, especially in the junction region of the Zi Ya He and Hei Long Gang watersheds. The 5 heavy metals in the sediments all had anthropogenic sources, and the enrichment degrees followed the order Cu > Pb > Zn > Cr > Ni, with mean enrichment factors of 3.27, 2.77, 2.58, 1.81, and 1.44, respectively. According to the mean index of comprehensive potential ecological risk (38.9), the studied sediments of the Haihe Basin showed low potential ecological risk, but the sediments were potentially biologically toxic based on the mean probable effect concentration quotient (0.547), which may be the result of speciation of the 5 metals in the sediments. The results indicate that heavy metal pollution should be considered during the development of ecological restoration strategies in the Haihe Basin. Environ Toxicol Chem 2017;36:1149-1155. © 2016 SETAC. © 2016 SETAC.

Heavy metal content and potential health risk of geophagic white clay from the Kumasi Metropolis in Ghana.

PubMed

Nkansah, Marian Asantewah; Korankye, Mavis; Darko, Godfred; Dodd, Matt

2016-01-01

Geophagia is the craving for non-food substances and commonly practiced among pregnant women and children. Consumption of geophagic clay samples can have serious implications on the health of the consumers as a result of the presence of toxic metals such as Pb, As, Hg and Cd. This study sought to determine the levels of heavy metals in the studied geophagic clay samples and to determine the potential risks of heavy metals as cumulative carcinogenic and non-carcinogenic risks to the health of the consumers via oral (ingestion) and dermal exposure routes. A total of thirty (30) white clay samples were analysed using Niton Thermo scientific XRF Analyser (Mobile Test S, NDTr-XL3t-86956, com 24). The clay samples were found to contain essential elements such as Ca, Fe, K and Zn as well as toxic metals such as As and Pb. There were isolated cases of the presence of Hg and all samples had Cd levels below detection. Health risk indices such as hazard quotient and cancer risk were calculated and the results indicated that consumers are likely to suffer from cancer through ingestion of geophagic clay. Bioaccessibility studies were done on zinc and it did not indicate any potential toxicity due to zincs essential nature. The levels of heavy metals in some of the geophagic clay consumed by some residents in the Kumasi were high compared to the Permitted Maximum Tolerable Daily Intake (PMTDI) by (WHO/FAO) and may pose potential health threat over time.

Leaching Behavior of Heavy Metals from Cement Pastes Using a Modified Toxicity Characteristic Leaching Procedure (TCLP).

PubMed

Huang, Minrui; Feng, Huajun; Shen, Dongsheng; Li, Na; Chen, Yingqiang; Shentu, Jiali

2016-03-01

As the standard toxicity characteristic leaching procedure (TCLP) can not exhaust the acid neutralizing capacity of the cement rotary kiln co-processing solid wastes products which is particularly important for the assessment of the leaching concentrations of heavy metals. A modified TCLP was proposed. The extent of leaching of heavy metals is low using the TCLP and the leaching performance of the different metals can not be differentiated. Using the modified TCLP, however, Zn leaching was negligible during the first 180 h and then sharply increased (2.86 ± 0.18 to 3.54 ± 0.26 mg/L) as the acidity increased (pH < 6.0). Thus, Zn leaching is enhanced using the modified TCLP. While Pb leached readily during the first 126 h and then leachate concentrations decreased to below the analytical detection limit. To conclude, this modified TCLP is a more suitable method for these cement rotary kiln co-processing products.

Removal of copper from aqueous solution using perlite

NASA Astrophysics Data System (ADS)

Tanaydin, Mehmet Kayra; Tanaydin, Zümra Bakici; Ince, Muharrem; Demırkiran, Nizamettin

2017-04-01

The wastewaters containing organic and inorganic pollutants after many industrial processes such as metal plating, mining, textile, alloy, battery and industrial chemicals, are often discharged to environment. Heavy metals among these pollutants have highly stable, toxic, non-degradable and carcinogenic characters. They affect not only ecological system, but also human health and many life forms. Therefore, these contaminants should be eliminated or reduced to allowable levels before releasing to environment. Most of heavy metals have toxic character even at low concentrations of about 0.1-0.3 ppm. Treatment technologies such as filtration, ion exchange, precipitation, electrodeposition, reverse osmosis, sedimentation, and adsorption have been applied for removal of heavy metals from aqueous solutions. Adsorption is one of the most common and widely applied methods to eliminate the metal ions from waste solutions because of its simplicity and cost effectiveness. Activated carbon, clay minerals, ion exchange resins and various agricultural residues can be used as adsorbent materials in this process [1-3].

Heavy metal bioaccumulation and effects on water hyacinth weevils, Neochetina eichhorniae, feeding on water hyacinth, Eichhornia crassipes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kay, S.H.; Haller, W.T.

1986-08-01

Both aquatic and terrestrial habitats frequently are subject to contamination by toxic heavy metals, yet very little is known about the influence of heavy metals absorbed by plant tissues upon the phytophagous insect fauna feeding upon these plants. The objectives of this study were to determine the influence of plant-absorbed metals upon the feeding, mortality, and body burdens of lead, cadmium, and copper in the water hyacinth weevil, Neochetina eichhorniae, imported for the biological control of water hyacinths (Eichhornia crassipes).

Halophytes--an emerging trend in phytoremediation.

PubMed

Manousaki, Eleni; Kalogerakis, Nicolas

2011-01-01

Halophytic plants are of special interest because these plants are naturally present in environments characterized by an excess of toxic ions, mainly sodium and chloride. Several studies have revealed that these plants may also tolerate other stresses including heavy metals based on the findings that tolerance to salt and to heavy metals may, at least partly, rely on common physiological mechanisms. In addition, it has been shown that salt-tolerant plants may also be able to accumulate metals. Therefore, halophytes have been suggested to be naturally better adapted to cope with environmental stresses, including heavy metals compared to salt-sensitive crop plants commonly chosen for phytoextraction purposes. Thus, potentially halophytes are ideal candidates for phytoextraction orphytostabilization of heavy metal polluted soils and moreover of heavy metal polluted soils affected by salinity. Some halophytes use excretion processes in order to remove the excess of salt ions from their sensitive tissues and in some cases these glandular structures are not always specific to Na+ and Cl- and other toxic elements such as cadmium, zinc, lead, or copper are accumulated and excreted by salt glands or trichomes on the surface of the leaves--a novel phytoremediation process called "phytoexcretion". Finally, the use of halophytes has also been proposed for soil desalination through salt accumulation in the plant tissue or dissolution of soil calcite in the rhizosphere to provide Ca2+ that can be exchanged with Na+ at cation exchange sites.

Zinc oxide nanoparticles (ZnONPs) alleviate heavy metal-induced toxicity in Leucaena leucocephala seedlings: A physiochemical analysis.

PubMed

Venkatachalam, P; Jayaraj, M; Manikandan, R; Geetha, N; Rene, Eldon R; Sharma, N C; Sahi, S V

2017-01-01

The present study describes the role of zinc oxide nanoparticles (ZnONPs) in reversing oxidative stress symptoms induced by heavy metal (Cd and Pb) exposure in Leucaena leucocephala (Lam.) de Wit. Seedling growth was significantly enhanced with the augmentation of ZnONPs following Cd and Pb exposure. Heavy metal accumulations were recorded as 1253.1 mg Cd per kg DW and 1026.8 mg Pb per kg DW for the respective treatments. Results demonstrated that ZnONPs augmentation caused an increase in photosynthetic pigment and total soluble protein contents while a significant decrease in malondialdehyde (MDA-lipid peroxidation) content in leaves. Antioxidative enzymes such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX) were, in turn, elevated in heavy metal-exposed leaves amended with ZnONPs. The ameliorating effect of ZnO nanoparticles on oxidative stress induced toxicity was also confirmed by the reduced MDA content and the elevated level of antioxidative enzyme activities in leaf tissues of L. leucocephala seedlings. Further, addition of ZnONPs in combination with Cd and Pb metals induced distinct genomic alterations such as presence of new DNA bands and/or absence of normal bands in the RAPD pattern of the exposed plants. This study uniquely suggests a potential role of zinc oxide nanoparticles in the remediation of heavy metal contaminated media. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Leaching Properties of Naturally Occurring Heavy Metals from Soils

NASA Astrophysics Data System (ADS)

Zhang, M.; Hoshino, M.; Yoshikawa, M.; Hara, J.; Sugita, H.

2014-12-01

The major threats to human health from heavy metals are associated with exposure to arsenic, lead, cadmium, chromium, mercury, as well as some other elements. The effects of such heavy metals on human health have been extensively studied and reviewed by international organizations such as WHO. Due to their toxicity, heavy metal contaminations have been regulated by national environmental standards in many countries, and/or laws such as the Soil Contamination Countermeasures Act in Japan. Leaching of naturally occurring heavy metals from the soils, especially those around abandoned metal mines into surrounding water systems, either groundwater or surface water systems, is one of the major pathways of exposure. Therefore, understanding the leaching properties of toxic heavy metals from naturally polluted soils is of fundamentally importance for effectively managing abandoned metal mines, excavated rocks discharged from infrastructure constructions such as tunneling, and/or selecting a pertinent countermeasure against pollution when it is necessary. In this study, soil samples taken from the surroundings of abandoned metal mines in different regions in Japan were collected and analyzed. The samples contained multiple heavy metals such as lead, arsenic and chromium. Standard leaching test and sequential leaching test considering different forms of contaminants, such as trivalent and pentavalent arsenics, and trivalent and hexavalent chromiums, together with standard test for evaluating total concentration, X-ray Fluorescence Analysis (XRF), X-ray diffraction analysis (XRD) and Cation Exchange Capacity (CEC) tests were performed. In addition, sequential leaching tests were performed to evaluate long-term leaching properties of lead from representative samples. This presentation introduces the details of the above experimental study, discusses the relationships among leaching properties and chemical and mineral compositions, indicates the difficulties associated with remediation of naturally polluted sites, and emphasizes the importance of risk-based countermeasures against naturally occurring heavy metals. Keywords: Leaching properties, Control Factor, Naturally Occurring Heavy Metals, Lead, Arsenic, Chromium

Chinese proprietary medicine in Singapore: regulatory control of toxic heavy metals and undeclared drugs.

PubMed

Koh, H L; Woo, S O

2000-11-01

Traditional Chinese medicine (TCM) is gaining popularity as a form of complementary and alternative medicine. Reports of efficacy of TCM are increasing in numbers. TCM includes both crude Chinese medicinal materials (plants, animal parts and minerals) and Chinese proprietary medicine (CPM) [final dosage forms]. Despite the belief that CPM and herbal remedies are of natural origin, unlike Western medicine, and are hence safe and without many adverse effects, there have been numerous reports of adverse effects associated with herbal remedies. Factors affecting the safety of herbal medicines include intrinsic toxicity, adulteration, substitution, contamination, misidentification, lack of standardisation, incorrect preparation and/or dosage and inappropriate labelling and/or advertising. Hence, new regulations on the control of CPM were enforced in Singapore with effect from 1 September 1999. These include licensing and labelling requirements, as well as control of microbial contamination. This article also reviews reports of excessive toxic heavy metals and undeclared drugs in CPM in Singapore between 1990 and 1997. The names, uses, toxic heavy metal or drug detected and the year of detection are tabulated. Information on the brand or manufacturer's name are provided whenever available. The public and healthcare professionals should be better informed of the basic concept of TCM and its usefulness, as well as the potential adverse effects associated with its use. Greater control over the safety and quality of CPM could be achieved through good manufacturing practice, regulatory control, research, education, reporting usage of Chinese medicine (as in drug history) as well as reporting of adverse events.

Differences in phytotoxicity and dissipation between ionized and nonionized oil sands naphthenic acids in wetland plants.

PubMed

Armstrong, Sarah A; Headley, John V; Peru, Kerry M; Germida, James J

2009-10-01

Naphthenic acids (NAs) are composed of alkyl-substituted acyclic and cycloaliphatic carboxylic acids and, because they are acutely toxic to fish, are of toxicological concern. During the caustic hot-water extraction of oil from the bitumen in oil sands deposits, NAs become concentrated in the resulting tailings pond water. The present study investigated if dissipation of NAs occurs in the presence of hydroponically grown emergent macrophytes (Typha latifolia, Phragmites australis, and Scirpus acutus) to determine the potential for phytoremediation of these compounds. Plants were grown with oil sands NAs (pKa approximately 5-6) in medium at pH 7.8 (predominantly ionized NAs) and pH 5.0 (predominantly nonionized NAs) to determine if, by altering their chemical form, NAs may be more accessible to plants and, thus, undergo increased dissipation. Whereas the oil sands NA mixture in its nonionized form was more toxic to wetland plants than its ionized form, neither form appeared to be sequestered by wetland plants. The present study demonstrated that plants may selectively enhance the dissipation of individual nonionized NA compounds, which contributes to toxicity reduction but does not translate into detectable total NA dissipation within experimental error and natural variation. Plants were able to reduce the toxicity of a NA system over 30 d, increasing the median lethal concentration (LC50; % of hydroponic solution) of the medium for Daphnia magna by 23.3% +/- 8.1% (mean +/- standard error; nonionized NAs) and 37.0% +/- 2.7% (ionized NAs) as determined by acute toxicity bioassays. This reduction in toxicity was 7.3% +/- 2.6% (nonionized NAs) and 45.0% +/- 6.8% (ionized NAs) greater than that in unplanted systems.

[Analysis of heavy-metal-mediated disease and development of a novel remediation system based on fieldwork and experimental research].

PubMed

Yajima, Ichiro; Zou, Cunchao; Li, Xiang; Nakano, Chizuru; Omata, Yasuhiro; Kumasaka, Mayuko Y

2015-01-01

Heavy-metal pollution occurs in various environments, including water, air and soil, and has serious effects on human health. Since heavy-metal pollution in drinking water causes various diseases including skin cancer, it has become a global problem worldwide. However, there is limited information on the mechanism of development of heavy-metal-mediated disease. We performed both fieldwork and experimental studies to elucidate the levels of heavy-metal pollution and mechanisms of development of heavy-metal-related disease and to develop a novel remediation system. Our fieldwork in Bangladesh, Vietnam and Malaysia demonstrated that drinking well water in these countries was polluted with high concentrations of several heavy metals including arsenic, barium, iron and manganese. Our experimental studies based on the data from our fieldwork demonstrated that these heavy metals caused skin cancer and hearing loss. Further experimental studies resulted in the development of a novel remediation system with which toxic heavy metals were absorbed from polluted drinking water. Implementation of both fieldwork and experimental studies is important for prediction, prevention and therapy of heavy-metal-mediated diseases.

Vertical profile, contamination assessment, and source apportionment of heavy metals in sediment cores of Kaohsiung Harbor, Taiwan.

PubMed

Chen, Chih-Feng; Ju, Yun-Ru; Chen, Chiu-Wen; Dong, Cheng-Di

2016-12-01

Six sediment cores collected at the Kaohsiung Harbor of Taiwan were analyzed to evaluate their vertical profiles, enrichments, accumulations, and source apportionments of heavy metals. This was performed to investigate any potential ecological risks posed by heavy metals. Results indicated that the mean heavy metal content (mg kg -1 ) in the six sediment cores was as follows: Hg (0.4-6.4), Cd (<0.05-2.4), Cr (18-820), Cu (16-760), Pb (31-140), and Zn (76-1900). The patterns of heavy metal content in the sediment cores differed substantially among the four river mouths. However, the vertical profiles of metals were relatively stable, indicating that wastewater has the constant characteristics and has been discharged into the rivers for a long period of time. Results of pollution assessment of enrichment factor, geo-accumulation index, and pollution load index revealed that river mouths experience severe enrichment, strong accumulation, and high contamination from the primary heavy metals. It was not consistent in the assessment results of mean effect range median quotient, potential ecological risk index, and total toxic unit method. Potential ecological risks caused by Hg in the sediments at Canon River and Love River mouths on aquatic organisms were extremely high. The estimates derived from the receptor modeling of multiple linear regression of the absolute principal component scores indicated that the contributions of the composite heavy metals derived from the Canon River and the Love River on the potential toxicity and risks to the water environment of Kaohsiung Harbor were highest, followed by those derived from Salt River and Jen-Gen River. Copyright © 2016 Elsevier Ltd. All rights reserved.

Determination of trace and heavy metals in some commonly used medicinal herbs in Ayurveda.

PubMed

Nema, Neelesh K; Maity, Niladri; Sarkar, Birendra K; Mukherjee, Pulok K

2014-11-01

Traditionally, the herbal drugs are well established for their therapeutic benefits. Depending upon their geographical sources sometimes the trace and heavy metals' content may differ, which may lead to severe toxicity. So, the toxicological and safety assessment of these herbal drugs are one of the major issues in recent days. Eight different plant species including Aloe vera, Centella asiatica, Calendula officinalis, Cucumis sativus, Camellia sinensis, Clitoria ternatea, Piper betel and Tagetes erecta were selected to determine their heavy and trace metals content and thereby to assure their safer therapeutic application. The trace and heavy metals were detected through atomic absorption spectrometry analysis. The selected medicinal plant materials were collected from the local cultivated regions of West Bengal, India, and were digested with nitric acid and hydrochloric acid as specified. Absorbance was measured through atomic absorption spectrometer (AA 303) and the concentration of different trace and heavy metals in the plant samples were calculated. The quantitative determinations were carried out using standard calibration curve obtained by the standard solutions of different metals. The contents of heavy metals were found to be within the prescribed limit. Other trace metals were found to be present in significant amount. Thus, on the basis of experimental outcome, it can be concluded that the plant materials collected from the specific region are safe and may not produce any harmful effect of metal toxicity during their therapeutic application. The investigated medicinal plants contain trace metals such as copper (Cu), chromium (Cr), manganese (Mn), iron (Fe) and nickel (Ni) as well as heavy metals such as arsenic (As), lead (Pb) and mercury (Hg), which were present within the permissible limit. © The Author(s) 2012.

Heavy Metals Induce Iron Deficiency Responses at Different Hierarchic and Regulatory Levels.

PubMed

Lešková, Alexandra; Giehl, Ricardo F H; Hartmann, Anja; Fargašová, Agáta; von Wirén, Nicolaus

2017-07-01

In plants, the excess of several heavy metals mimics iron (Fe) deficiency-induced chlorosis, indicating a disturbance in Fe homeostasis. To examine the level at which heavy metals interfere with Fe deficiency responses, we carried out an in-depth characterization of Fe-related physiological, regulatory, and morphological responses in Arabidopsis ( Arabidopsis thaliana ) exposed to heavy metals. Enhanced zinc (Zn) uptake closely mimicked Fe deficiency by leading to low chlorophyll but high ferric-chelate reductase activity and coumarin release. These responses were not caused by Zn-inhibited Fe uptake via IRON-REGULATED TRANSPORTER (IRT1). Instead, Zn simulated the transcriptional response of typical Fe-regulated genes, indicating that Zn affects Fe homeostasis at the level of Fe sensing. Excess supplies of cobalt and nickel altered root traits in a different way from Fe deficiency, inducing only transient Fe deficiency responses, which were characterized by a lack of induction of the ethylene pathway. Cadmium showed a rather inconsistent influence on Fe deficiency responses at multiple levels. By contrast, manganese evoked weak Fe deficiency responses in wild-type plants but strongly exacerbated chlorosis in irt1 plants, indicating that manganese antagonized Fe mainly at the level of transport. These results show that the investigated heavy metals modulate Fe deficiency responses at different hierarchic and regulatory levels and that the interaction of metals with physiological and morphological Fe deficiency responses is uncoupled. Thus, this study not only emphasizes the importance of assessing heavy metal toxicities at multiple levels but also provides a new perspective on how Fe deficiency contributes to the toxic action of individual heavy metals. © 2017 American Society of Plant Biologists. All Rights Reserved.

Biophotonics of the interaction of low-intensity laser radiation with blood erythrocytes

NASA Astrophysics Data System (ADS)

Asimov, M. M.; Asimov, R. M.; Batyan, A. N.; Trusevich, M. O.; Rubinov, A. N.

2013-06-01

We have studied experimentally how optical radiation affects the neutralization of the toxic action of heavy metals and harmful chemical compounds (ecotoxicants) on the oxygen-transport function of blood erythrocytes. It has been found that the optical radiation has a stabilizing effect and prevents lowering the erythrocyte concentration in the presence of phenol and heavy metals in blood. We have studied the neutralization efficiency of the toxic action of ecotoxicants in relation to the laser irradiation time. The obtained data on the effect of the laser radiation on the thermal denaturation of hemoglobin and erythrocytes yield the scientific substantiation to the development of the optical method for the use in medicine upon drawing and conserving donor blood. We have shown that the obtained data can be used in medicine for improving the reliability of conditions of conservation and storage of donor blood, as well as for preventing the toxic action of harmful chemical compounds in the environment.

Effect of advanced aftertreatment for PM and NOx reduction on heavy-duty diesel engine ultrafine particle emissions.

PubMed

Herner, Jorn Dinh; Hu, Shaohua; Robertson, William H; Huai, Tao; Chang, M-C Oliver; Rieger, Paul; Ayala, Alberto

2011-03-15

Four heavy-duty and medium-duty diesel vehicles were tested in six different aftertreament configurations using a chassis dynamometer to characterize the occurrence of nucleation (the conversion of exhaust gases to particles upon dilution). The aftertreatment included four different diesel particulate filters and two selective catalytic reduction (SCR) devices. All DPFs reduced the emissions of solid particles by several orders of magnitude, but in certain cases the occurrence of a volatile nucleation mode could increase total particle number emissions. The occurrence of a nucleation mode could be predicted based on the level of catalyst in the aftertreatment, the prevailing temperature in the aftertreatment, and the age of the aftertreatment. The particles measured during nucleation had a high fraction of sulfate, up to 62% of reconstructed mass. Additionally the catalyst reduced the toxicity measured in chemical and cellular assays suggesting a pathway for an inverse correlation between particle number and toxicity. The results have implications for exposure to and toxicity of diesel PM.

Adsorption of oils, heavy metals and dyes by recovered carbon powder from spent pot liner of aluminum smelter plant.

PubMed

Mazumder, B; Devi, Sasmita Rani

2008-07-01

Aluminum smelter plants employ Hall-Heroult electrolysis cells for electrolysis of molten cryolite to recover aluminum metal by electrolysis. These cells use carbon cathode blocks as a lining material inside. At the end of service life of the cells, pot lines are discarded and new carbon blocks are laid for fresh charging. These used carbon cathode blocks, known as spent pot liners, are heavily infested with toxic elements such as fluoride, cyanide, alkali, etc. Therefore, their disposal in open field poses great environmental risk. A simple process has been developed for decontamination of these spent pot liners and to recover its carbon value. The experiments indicated that this carbon, in the form of fine powder (around 20 micron in size) can absorb toxic elements like heavy metals, dyes, oils, etc. to a great extent and thus can be used for mitigating environmental pollution occuring due to various toxic wastes.

Heavy Metal Contents of Soils, Durum and Bread Wheats in Harran Plain, Southeast Turkey

NASA Astrophysics Data System (ADS)

Büyükkılıç Yanardaǧ, Asuman

2013-04-01

Soils are vital for regulating the biological effects and mobility of metals in nature. Iron and zinc are some of the essential nutrients for plants and animals, while other metals are potentially toxic such as lead and cadmium. Toxic heavy metals (HMs) can be taken up easily by organisms. HMs inputs to soil via the application of metal-contained fertilizers often exceed outputs in crops and drainage waters, thus toxic HMs content in many agricultural soils tends to be gradually increasing. Thus adverse human health effects due to soil-plant and plant-human transfer of HMs have been enhanced. HMs may cause harmful effects on human health due to the ingestion of food grain grown in soils. The objectives of this study were (1) to understand the chemistry of metals in soils for managing their agricultural and ecological impacts, (2) to identify metal uptakes of different genotypes of wheat. Concentrations of HMs (Cd, Zn, Ni, Mn, Cu, Mo, Pb) in wheat were investigated in different agricultural areas in Southeast, Turkey. The results showed that concentrations of HMs were in following order: Mn>Ni>Zn>Cu>Pb>Mo>Cd in surface and next to surface soil and Mn>Zn>Cu>Pb> Ni>Mo>Cd in wheat, respectively. HMs concentrations of several soil samples exceeded the permissible limits of Europe standard except for Ni and Mn. In addition, concentration of Cd, Zn, Cu, and Pb were higher in bread wheat than in durum wheat; however, concentration of Mn, Ni and Mo were higher in durum wheat than in bread wheat. Unusual amount of heavy metals found in some fertilizers used in the Southeast region of Turkey, it becomes an important subject to determine the amount of metals added to the soil every year. Heavy metals uptake by plants still remains to be an interest for researchers. As the heavy metals contents of plants were below the threshold levels, we conclude that the quality of wheat is high and it should receive attention in national and international markets. Keywords: Heavy Metals (HMs), Soil, Durum and Bread Wheat, Fertilizers.

Heavy Metals Contamination in Coastal Sediments of Karachi, Pakistan

NASA Astrophysics Data System (ADS)

Siddique, A.; Mumtaz, M.; Zaigham, N. A.; Mallick, K. A.; Saied, S.; Khwaja, H. A.

2008-12-01

Toxic compounds such as heavy metals exert chronic and lethal effects in animals, plants, and human health. With the rapid industrialization, urbanization, and economic development in Karachi, heavy metals are continuing to be introduced to estuarine and coastal environment through rivers, runoff and land-based point sources. Pollution in the Karachi coastal region (167 km long) is mainly attributed to Lyari and Malir Rivers flowing through the city of Karachi. Both rivers are served by various channels of domestic and industrial wastes carrying more than 300 million gallons per day untreated effluent of 6000 industries and ultimately drain into the beaches of Arabian Sea. Concentrations of selected heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in surface sediments from eighty-eight sites in Karachi coastal region were studied in order to understand metal contamination due to industrialization, urbanization, and economic development in Karachi. Sediment samples were collected in 2005 and 2006. We have found that heavy metal concentrations in surface sediments varied from 0.006 to 24.3 ug/g for Cd, 5.1 to 95 ug/g for Co, 2.9 to 571 ug/g for Cr, 6.9 to 272 ug/g for Cu, 0.55 to 6.5% for Fe, 1.2 to 318 ug/g for Mn, 7.5 to 75 ug/g for Ni, 6.3 to 121 ug/g for Pb, and 3.3 to 389 ug/g for Zn. Enrichment factors (EFs) were calculated to assess whether the concentrations observed represent background or contaminated levels. The highest levels of metals were found to be at the confluence of the Lyari and Malir River streams at the Arabian Sea, indicating the impact of the effluents of the highly urbanized and industrialized city of Karachi. Furthermore, this study assessed heavy metal toxicity risk with the application of Sediment Quality Guideline (SQG) indices (effect range low/effect range median values, ERL/ERM). Results indicated that the potential toxicity of marine environment can cause adverse biological effects to the biota directly and the human health indirectly through food web chain.

Agroforestry: working trees for sequestering carbon on agricultural lands

Treesearch

M.M. Schoeneberger

2008-01-01

Agroforestry is an appealing option for sequestering carbon on agricultural lands because it can sequester significant amounts of carbon while leaving the bulk of the land in agricultural production. Simultaneously, it can help landowners and society address many other issues facing these lands, such as economic diversification, biodiversity, and water quality....

Agroforestry-working trees for sequestering carbon on ag-lands

Treesearch

Michele M. Schoeneberger

2005-01-01

Agroforestry is an appealing option for sequestering carbon on agricultural lands because it can sequester significant amounts of carbon whle leaving the bulk of the land in agricultural production. Simultaneously, it can help landowners and society address many other issues, such as economic diversification, biodiversity, and water quality, facing these lands....

Annotated Bibliography of Bioassays Related to Sediment Toxicity Testing in Washington State

DTIC Science & Technology

1990-10-01

effects of sediments contaminated with heavy metals, petroleum hydrocarbons , synthetic organic compounds and radionuclides. It also provides an... molluscs (adults only), echinoderm larvae and fish), and bioassay procedures with selected toxicants (metals, petrochemicals, pesticides, contaminated...reference sediment + 15 mm test sediment. Bioaccumulation tests (with same organisms) are a’so discussed. EPA/COE (U.S. Environmental Protection Agency

Heavy metal-immobilizing organoclay facilitates polycyclic aromatic hydrocarbon biodegradation in mixed-contaminated soil.

PubMed

Biswas, Bhabananda; Sarkar, Binoy; Mandal, Asit; Naidu, Ravi

2015-11-15

Soils contaminated with a mixture of heavy metals and polycyclic aromatic hydrocarbons (PAHs) pose toxic metal stress to native PAH-degrading microorganisms. Adsorbents such as clay and modified clay minerals can bind the metal and reduce its toxicity to microorganisms. However, in a mixed-contaminated soil, an adsorption process more specific to the metals without affecting the bioavailability of PAHs is desired for effective degradation. Furthermore, the adsorbent should enhance the viability of PAH-degrading microorganisms. A metal-immobilizing organoclay (Arquad(®) 2HT-75-bentonite treated with palmitic acid) (MIOC) able to reduce metal (cadmium (Cd)) toxicity and enhance PAH (phenanthrene) biodegradation was developed and characterized in this study. The MIOC differed considerably from the parent clay in terms of its ability to reduce metal toxicity (MIOC>unmodified bentonite>Arquad-bentonite). The MIOC variably increased the microbial count (10-43%) as well as activities (respiration 3-44%; enzymatic activities up to 68%), and simultaneously maintained phenanthrene in bioavailable form in a Cd-phenanthrene mixed-contaminated soil over a 21-day incubation period. This study may lead to a new MIOC-assisted bioremediation technique for PAHs in mixed-contaminated soils. Copyright © 2015 Elsevier B.V. All rights reserved.

Cadmium Handling, Toxicity and Molecular Targets Involved during Pregnancy: Lessons from Experimental Models.

PubMed

Jacobo-Estrada, Tania; Santoyo-Sánchez, Mitzi; Thévenod, Frank; Barbier, Olivier

2017-07-22

Even decades after the discovery of Cadmium (Cd) toxicity, research on this heavy metal is still a hot topic in scientific literature: as we wrote this review, more than 1440 scientific articles had been published and listed by the PubMed.gov website during 2017. Cadmium is one of the most common and harmful heavy metals present in our environment. Since pregnancy is a very particular physiological condition that could impact and modify essential pathways involved in the handling of Cd, the prenatal life is a critical stage for exposure to this non-essential element. To give the reader an overview of the possible mechanisms involved in the multiple organ toxic effects in fetuses after the exposure to Cd during pregnancy, we decided to compile some of the most relevant experimental studies performed in experimental models and to summarize the advances in this field such as the Cd distribution and the factors that could alter it (diet, binding-proteins and membrane transporters), the Cd-induced toxicity in dams (preeclampsia, fertility, kidney injury, alteration in essential element homeostasis and bone mineralization), in placenta and in fetus (teratogenicity, central nervous system, liver and kidney).

Cadmium Handling, Toxicity and Molecular Targets Involved during Pregnancy: Lessons from Experimental Models

PubMed Central

Santoyo-Sánchez, Mitzi; Thévenod, Frank; Barbier, Olivier

2017-01-01

Even decades after the discovery of Cadmium (Cd) toxicity, research on this heavy metal is still a hot topic in scientific literature: as we wrote this review, more than 1440 scientific articles had been published and listed by the PubMed.gov website during 2017. Cadmium is one of the most common and harmful heavy metals present in our environment. Since pregnancy is a very particular physiological condition that could impact and modify essential pathways involved in the handling of Cd, the prenatal life is a critical stage for exposure to this non-essential element. To give the reader an overview of the possible mechanisms involved in the multiple organ toxic effects in fetuses after the exposure to Cd during pregnancy, we decided to compile some of the most relevant experimental studies performed in experimental models and to summarize the advances in this field such as the Cd distribution and the factors that could alter it (diet, binding-proteins and membrane transporters), the Cd-induced toxicity in dams (preeclampsia, fertility, kidney injury, alteration in essential element homeostasis and bone mineralization), in placenta and in fetus (teratogenicity, central nervous system, liver and kidney). PMID:28737682

The Effect of Traditional Treatments on Heavy Metal Toxicity of Armenian Bole

PubMed Central

Hosamo, Ammar; Zarshenas, Mohammad Mehdi; Mehdizadeh, Alireza; Zomorodian, Kamiar; Khani, Ayda Hossein

2016-01-01

Background: Clay has been used for its nutrition, cosmetic, and antibacterial properties for thousands of years. Its small particle size, large surface area, and high concentration of ions have made it an interesting subject for pharmaceutical research. There have been studies on scavenging foreign substances and antibacterial properties of clay minerals. The main problem with the medical use of these agents, today, is their heavy metal toxicity. This includes arsenic, cadmium, lead, nickel, zinc, and iron. Iranian traditional medicine (ITM) introduces different clays as medicaments. In this system, there are specific processes for these agents, which might reduce the chance of heavy metal toxicity. Armenian bole is a type of clay that has been used to treat a wound. Before in vivo studies of this clay, its safety should be confirmed. Methods: In this work, we investigated the effect of washing process as mentioned in ITM books regarding the presence of Pb, As, and Cd in 5 samples using atomic absorption spectrometry. We washed each sample (50 g) with 500 cc of distilled water. The samples were filtered and dried at room temperature for 24 hours. Results: In all studied samples, the amount of Pb and Cd was reduced after the ITM washing process. The amount of As was reduced in 3 samples and increased in 2 other samples. Conclusion: In ITM books, there are general considerations for the use of medicinal clay. These agents should not be used before special treatments such as the washing process. In this study, we observed the effect of washing process on reducing the amount of heavy metals in Armenian bole samples. In two samples, washing caused an increase in the amount of As. As these heavy metals sediment according to their density in different layers, the sample layer on which the spectrometry is performed could have an effect on the results. PMID:27840531

The Effect of Traditional Treatments on Heavy Metal Toxicity of Armenian Bole

PubMed Central

Hosamo, Ammar; Zarshenas, Mohammad Mehdi; Mehdizadeh, Alireza; Zomorodian, Kamiar; Khani, Ayda Hossein

2016-01-01

Background: Clay has been used for its nutrition, cosmetic, and antibacterial properties for thousands of years. Its small particle size, large surface area, and high concentration of ions have made it an interesting subject for pharmaceutical research. There have been studies on scavenging foreign substances and antibacterial properties of clay minerals. The main problem with the medical use of these agents, today, is their heavy metal toxicity. This includes arsenic, cadmium, lead, nickel, zinc, and iron. Iranian traditional medicine (ITM) introduces different clays as medicaments. In this system, there are specific processes for these agents, which might reduce the chance of heavy metal toxicity. Armenian bole is a type of clay that has been used to treat a wound. Before in vivo studies of this clay, its safety should be confirmed. Methods: In this work, we investigated the effect of washing process as mentioned in ITM books regarding the presence of Pb, As, and Cd in 5 samples using atomic absorption spectrometry. We washed each sample (50 g) with 500 cc of distilled water. The samples were filtered and dried at room temperature for 24 hours. Results: In all studied samples, the amount of Pb and Cd was reduced after the ITM washing process. The amount of As was reduced in 3 samples and increased in 2 other samples. Conclusion: In ITM books, there are general considerations for the use of medicinal clay. These agents should not be used before special treatments such as the washing process. In this study, we observed the effect of washing process on reducing the amount of heavy metals in Armenian bole samples. In two samples, washing caused an increase in the amount of As. As these heavy metals sediment according to their density in different layers, the sample layer on which the spectrometry is performed could have an effect on the results. PMID:27516695

Acute Toxicity, Respiratory Reaction, and Sensitivity of Three Cyprinid Fish Species Caused by Exposure to Four Heavy Metals

PubMed Central

Wang, Hongjun; Liang, Youguang; Li, Sixin; Chang, Jianbo

2013-01-01

Using 3 cyprinid fish species zebra fish, rare minnow, and juvenile grass carp, we conducted assays of lethal reaction and ventilatory response to analyze sensitivity of the fish to 4 heavy metals. Our results showed that the 96 h LC50 of Hg2+ to zebra fish, juvenile grass carp, and rare minnow were 0.14 mg L−1, 0.23 mg L−1, and 0.10 mg L−1, respectively; of Cu2+0.17 mg L−1, 0.09 mg L−1, and 0.12 mg L−1 respectively; of Cd2+6.5 mg L−1, 18.47 mg L−1, 5.36 mg L−1, respectively; and of Zn2+44.48 mg L−1, 31.37 mg L−1, and 12.74 mg L−1, respectively. Under a 1-h exposure, the ventilatory response to the different heavy metals varied. Ventilatory frequency (Vf) and amplitude (Va) increased in zebra fish, juvenile grass carp, and rare minnows exposed to Hg2+ and Cu2+ (P<0.05), and the Vf and Va of the 3 species rose initially and then declined when exposed to Cd2+. Zn2+ had markedly different toxic effects than the other heavy metals, whose Vf and Va gradually decreased with increasing exposure concentration (P<0.05). The rare minnow was the most highly susceptible of the 3 fish species to the heavy metals, with threshold effect concentrations (TEC) of 0.019 mg L−1, 0.046 mg L−1, 2.142 mg L−1, and 0.633 mg L−1 for Hg2+, Cu2+, Cd2+, and Zn2+, respectively. Therefore, it is feasible to use ventilatory parameters as a biomarker for evaluating the pollution toxicity of metals and to recognize early warning signs by using rare minnows as a sensor. PMID:23755209

The Effect of Traditional Treatments on Heavy Metal Toxicity of Armenian Bole.

PubMed

Hosamo, Ammar; Zarshenas, Mohammad Mehdi; Mehdizadeh, Alireza; Zomorodian, Kamiar; Khani, Ayda Hossein

2016-05-01

Clay has been used for its nutrition, cosmetic, and antibacterial properties for thousands of years. Its small particle size, large surface area, and high concentration of ions have made it an interesting subject for pharmaceutical research. There have been studies on scavenging foreign substances and antibacterial properties of clay minerals. The main problem with the medical use of these agents, today, is their heavy metal toxicity. This includes arsenic, cadmium, lead, nickel, zinc, and iron. Iranian traditional medicine (ITM) introduces different clays as medicaments. In this system, there are specific processes for these agents, which might reduce the chance of heavy metal toxicity. Armenian bole is a type of clay that has been used to treat a wound. Before in vivo studies of this clay, its safety should be confirmed. In this work, we investigated the effect of washing process as mentioned in ITM books regarding the presence of Pb, As, and Cd in 5 samples using atomic absorption spectrometry. We washed each sample (50 g) with 500 cc of distilled water. The samples were filtered and dried at room temperature for 24 hours. In all studied samples, the amount of Pb and Cd was reduced after the ITM washing process. The amount of As was reduced in 3 samples and increased in 2 other samples. In ITM books, there are general considerations for the use of medicinal clay. These agents should not be used before special treatments such as the washing process. In this study, we observed the effect of washing process on reducing the amount of heavy metals in Armenian bole samples. In two samples, washing caused an increase in the amount of As. As these heavy metals sediment according to their density in different layers, the sample layer on which the spectrometry is performed could have an effect on the results.

Rhizobacteria and plant symbiosis in heavy metal uptake and its implications for soil bioremediation.

PubMed

Sobariu, Dana Luminița; Fertu, Daniela Ionela Tudorache; Diaconu, Mariana; Pavel, Lucian Vasile; Hlihor, Raluca-Maria; Drăgoi, Elena Niculina; Curteanu, Silvia; Lenz, Markus; Corvini, Philippe François-Xavier; Gavrilescu, Maria

2017-10-25

Certain species of plants can benefit from synergistic effects with plant growth-promoting rhizobacteria (PGPR) that improve plant growth and metal accumulation, mitigating toxic effects on plants and increasing their tolerance to heavy metals. The application of PGPR as biofertilizers and atmospheric nitrogen fixators contributes considerably to the intensification of the phytoremediation process. In this paper, we have built a system consisting of rhizospheric Azotobacter microbial populations and Lepidium sativum plants, growing in solutions containing heavy metals in various concentrations. We examined the ability of the organisms to grow in symbiosis so as to stimulate the plant growth and enhance its tolerance to Cr(VI) and Cd(II), to ultimately provide a reliable phytoremediation system. The study was developed at the laboratory level and, at this stage, does not assess the inherent interactions under real conditions occurring in contaminated fields with autochthonous microflora and under different pedoclimatic conditions and environmental stresses. Azotobacter sp. bacteria could indeed stimulate the average germination efficiency of Lepidium sativum by almost 7%, average root length by 22%, average stem length by 34% and dry biomass by 53%. The growth of L. sativum has been affected to a greater extent in Cd(II) solutions due its higher toxicity compared to that of Cr(VI). The reduced tolerance index (TI, %) indicated that plant growth in symbiosis with PGPR was however affected by heavy metal toxicity, while the tolerance of the plant to heavy metals was enhanced in the bacteria-plant system. A methodology based on artificial neural networks (ANNs) and differential evolution (DE), specifically a neuro-evolutionary approach, was applied to model germination rates, dry biomass and root/stem length and proving the robustness of the experimental data. The errors associated with all four variables are small and the correlation coefficients higher than 0.98, which indicate that the selected models can efficiently predict the experimental data. Copyright © 2016. Published by Elsevier B.V.

Distribution and pollution, toxicity and risk assessment of heavy metals in sediments from urban and rural rivers of the Pearl River delta in southern China.

PubMed

Xiao, Rong; Bai, Junhong; Huang, Laibin; Zhang, Honggang; Cui, Baoshan; Liu, Xinhui

2013-12-01

Sediments were collected from the upper, middle and lower reaches of both urban and rural rivers in a typical urbanization zone of the Pearl River delta. Six heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) were analyzed in all sediment samples, and their spatial distribution, pollution levels, toxicity and ecological risk levels were evaluated to compare the characteristics of heavy metal pollution between the two rivers. Our results indicated that the total contents of the six metals in all samples exceeded the soil background value in Guangdong province. Based on the soil quality thresholds of the China SEPA, Cd levels at all sites exceeded class III criteria, and other metals exhibited pollution levels exceeding class II or III criteria at both river sites. According to the sediment quality guidelines of the US EPA, all samples were moderately to heavily polluted by Cr, Cu, Ni, Pb and Zn. Compared to rural river sites, urban river sites exhibited heavier pollution. Almost all sediment samples from both rivers exhibited moderate to serious toxicity to the environment, with higher contributions from Cr and Ni. A "hot area" of heavy metal pollution being observed in the upper and middle reaches of the urban river area, whereas a "hot spot" was identified at a specific site in the middle reach of the rural river. Contrary metal distribution patterns were also observed along typical sediment profiles from urban and rural rivers. However, the potential ecological risk indices of rural river sediments in this study were equal to those of urban river sediments, implying that the ecological health issues of the rivers in the undeveloped rural area should also be addressed. Sediment organic matter and grain size might be important factors influencing the distribution profiles of these heavy metals.

How and why do toxic conformers of aberrant proteins accumulate during ageing?

PubMed

Josefson, Rebecca; Andersson, Rebecca; Nyström, Thomas

2017-07-15

Ageing can be defined as a gradual decline in cellular and physical functions accompanied by an increased sensitivity to the environment and risk of death. The increased risk of mortality is causally connected to a gradual, intracellular accumulation of so-called ageing factors, of which damaged and aggregated proteins are believed to be one. Such aggregated proteins also contribute to several age-related neurodegenerative disorders e.g. Alzheimer's, Parkinson's, and Huntington's diseases, highlighting the importance of protein quality control (PQC) in ageing and its associated diseases. PQC consists of two interrelated systems: the temporal control system aimed at refolding, repairing, and/or removing aberrant proteins and their aggregates and the spatial control system aimed at harnessing the potential toxicity of aberrant proteins by sequestering them at specific cellular locations. The accumulation of toxic conformers of aberrant proteins during ageing is often declared to be a consequence of an incapacitated temporal PQC system-i.e. a gradual decline in the activity of chaperones and proteases. Here, we review the current knowledge on PQC in relation to ageing and highlight that the breakdown of both temporal and spatial PQC may contribute to ageing and thus comprise potential targets for therapeutic interventions of the ageing process. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

The chaperonin CCT promotes the formation of fibrillar aggregates of γ-tubulin.

PubMed

Pouchucq, Luis; Lobos-Ruiz, Pablo; Araya, Gissela; Valpuesta, José María; Monasterio, Octavio

2018-04-01

The type II chaperonin CCT is involved in the prevention of the pathogenesis of numerous human misfolding disorders, as it sequesters misfolded proteins, blocks their aggregation and helps them to achieve their native state. In addition, it has been reported that CCT can prevent the toxicity of non-client amyloidogenic proteins by the induction of non-toxic aggregates, leading to new insight in chaperonin function as an aggregate remodeling factor. Here we add experimental evidence to this alternative mechanism by which CCT actively promotes the formation of conformationally different aggregates of γ-tubulin, a non-amyloidogenic CCT client protein, which are mediated by specific CCT-γ-tubulin interactions. The in vitro-induced aggregates were in some cases long fiber polymers, which compete with the amorphous aggregates. Direct injection of unfolded purified γ-tubulin into single-cell zebra fish embryos allowed us to relate this in vitro activity with the in vivo formation of intracellular aggregates. Injection of a CCT-binding deficient γ-tubulin mutant dramatically diminished the size of the intracellular aggregates, increasing the toxicity of the misfolded protein. These results point to CCT having a role in the remodeling of aggregates, constituting one of its many functions in cellular proteostasis. Copyright © 2018. Published by Elsevier B.V.

Investigation on Leaching Behaviour of Fly Ash and Bottom Ash Replacement in Self-Compacting Concrete

NASA Astrophysics Data System (ADS)

Kadir, Aeslina Abdul; Ikhmal Haqeem Hassan, Mohd; Bakri Abdullah, Mohd Mustafa Al

2016-06-01

Fly ash and bottom ash are some of the waste generated by coal-fired power plants, which contains large quantities of toxic and heavy metals. In recent years, many researchers have been interested in studying on the properties of self-compacting concrete incorporated with fly ash and bottom ash but there was very limited research from the combination of fly ash and bottom ash towards the environmental needs. Therefore, this research was focused on investigating the leachability of heavy metals of SCC incorporated with fly ash and bottom ash by using Toxicity Characteristic Leaching Procedure, Synthetic Precipitation Leaching Procedure and Static Leaching Test. The samples obtained from the coal-fired power plant located at Peninsula, Malaysia. In this study, the potential heavy metals leached out from SCC that is produced with fly ash as a replacement for Ordinary Portland Cement and bottom ash as a substitute for sand with the ratios from 10% to 30% respectively were designated and cast. There are eight heavy metals of concern such as As, Cr, Pb, Zn, Cu, Ni, Mn and Fe. The results indicated that most of the heavy metals leached below the permissible limits from the United States Environmental Protection Agency and World Health Organization limit for drinking water. As a conclusion, the minimum leaching of the heavy metals from the incorporation of fly ash and bottom ash in self-compacting concrete was found in 20% of fly ash and 20% of bottom ash replacement. The results also indicate that this incorporation could minimize the potential of environmental problems.

The SEQUEST Family Tree

NASA Astrophysics Data System (ADS)

Tabb, David L.

2015-11-01

Since its introduction in 1994, SEQUEST has gained many important new capabilities, and a host of successor algorithms have built upon its successes. This Account and Perspective maps the evolution of this important tool and charts the relationships among contributions to the SEQUEST legacy. Many of the changes represented improvements in computing speed by clusters and graphics cards. Mass spectrometry innovations in mass accuracy and activation methods led to shifts in fragment modeling and scoring strategies. These changes, as well as the movement of laboratories and lab members, have led to great diversity among the members of the SEQUEST family.

Pollution status of Pakistan: a retrospective review on heavy metal contamination of water, soil, and vegetables.

PubMed

Waseem, Amir; Arshad, Jahanzaib; Iqbal, Farhat; Sajjad, Ashif; Mehmood, Zahid; Murtaza, Ghulam

2014-01-01

Trace heavy metals, such as arsenic, cadmium, lead, chromium, nickel, and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. In addition to these metals, copper, manganese, iron, and zinc are also important trace micronutrients. The presence of trace heavy metals in the atmosphere, soil, and water can cause serious problems to all organisms, and the ubiquitous bioavailability of these heavy metal can result in bioaccumulation in the food chain which especially can be highly dangerous to human health. This study reviews the heavy metal contamination in several areas of Pakistan over the past few years, particularly to assess the heavy metal contamination in water (ground water, surface water, and waste water), soil, sediments, particulate matter, and vegetables. The listed contaminations affect the drinking water quality, ecological environment, and food chain. Moreover, the toxicity induced by contaminated water, soil, and vegetables poses serious threat to human health.

Impact of Heavy Metal Pollution on Ammonia Oxidizers in Soils in the Vicinity of a Tailings Dam, Baotou, China.

PubMed

Liu, Jumei; Cao, Weiwei; Jiang, Haiming; Cui, Jing; Shi, Chunfang; Qiao, Xiaohui; Zhao, Ji; Si, Wantong

2018-05-09

Soil heavy metal pollution has received increasing attention due to their toxicity to soil microorganisms. We have analyzed the effects of heavy metal pollution on ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in soils in the vicinity of a tailings dam of Baotou region, China. Results showed that AOB were dominated with Nitrosomonas-like clusters, while AOA was dominated by group1.1b (Nitrososphaera cluster). Single Cd and Cr contents, as well as compound heavy metal pollution levels, had a significant negative impact on soil potential nitrification rate and both diversities of AOA and AOB. No clear relationship was found between any single heavy metal and abundance of AOA or AOB. But compound pollution could significantly decrease AOA abundance. The results indicated that heavy metal pollution had an obviously deleterious effect on the abundance, diversity, activity and composition of ammonia oxidizers in natural soils.

New Technique for Speciation of Uranium in Sediments Following Acetate-Stimulated Bioremediation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2011-06-22

Acetate-stimulated bioremediation is a promising new technique for sequestering toxic uranium contamination from groundwater. The speciation of uranium in sediments after such bioremediation attempts remains unknown as a result of low uranium concentration, and is important to analyzing the stability of sequestered uranium. A new technique was developed for investigating the oxidation state and local molecular structure of uranium from field site sediments using X-Ray Absorption Spectroscopy (XAS), and was implemented at the site of a former uranium mill in Rifle, CO. Glass columns filled with bioactive Rifle sediments were deployed in wells in the contaminated Rifle aquifer and amendedmore » with a hexavalent uranium (U(VI)) stock solution to increase uranium concentration while maintaining field conditions. This sediment was harvested and XAS was utilized to analyze the oxidation state and local molecular structure of the uranium in sediment samples. Extended X-Ray Absorption Fine Structure (EXAFS) data was collected and compared to known uranium spectra to determine the local molecular structure of the uranium in the sediment. Fitting was used to determine that the field site sediments did not contain uraninite (UO{sub 2}), indicating that models based on bioreduction using pure bacterial cultures are not accurate for bioremediation in the field. Stability tests on the monomeric tetravalent uranium (U(IV)) produced by bioremediation are needed in order to assess the efficacy of acetate-stimulation bioremediation.« less

Study on nitrification process in two calcareous and non-calcareous contaminated soils

NASA Astrophysics Data System (ADS)

Yazdanpanah, Najme

2010-05-01

Heavy metals are well known to be toxic to most microorganisms when present in high concentration in the soil. They are a serious threat to soil quality due to their persistence after entering the soil. It has been demonstrated repeatedly that heavy metals adversely affect biological functions in soil. While calcareous soils are widespread in Iran, there is lack of information on the behavior of microbial activity in the presence of heavy metals in these soils. Therefore, the aim of this study was to investigate the effect of Cd and Zn as pollutant on nitrification process in two calcareous and non-calcareous soils. After additions of 0, 10 and 100 µg Cd g-1 and 0, 100 and 500 µg Zn g-1 to the soils, nitrification in the presence and absence of ammonium was measured after 45 days incubation. Nitrification results showed that nitrate decreased in both treated soils. Toxic effect of Cd and Zn intensified with increase of metal concentration. The difference of nitrate in samples without ammonium was more pronounced than ammonium treated ones. Nitrification led to decrease in soil pH which was intensified especially in non-calcareous soil. The results of this study indicated that toxic effect of Cd and Zn on measured nitrification was more evident in non- calcareous soil. Keywords: Nitrification, Cadmium, Zinc, Calcareous and non-calcareous soil.

Heavy metals pollution status in surface sediments (rivers and artifical lakes, Serbia)

NASA Astrophysics Data System (ADS)

Sakan, Sanja; Đorđević, Dragana

2017-04-01

Potentially hazardous trace elements, often in literature referred as "heavy metals", are deemed serious pollutants due to their toxicity, persistence and non-degradability in the environment. These elements play an important role in extent of water pollution and threaten the health of populations and ecosystems. As the sink of heavy metals, sediment beds adsorb metals in quantities that are many times higher than those found in the water column in the long-term polluted water environment. It is believed that most of the metal content, as much as 90% in aquatic sediments is bound to sediments. Metal contamination in these sediments could be directly affect the river water quality, resulting in potential consequences to the sensitive lowest levels of the food chain and ultimately to human health. The objective of this research was the evaluation of heavy metal contamination level in sediments of the most important rivers and artificial lakes in Serbia. The heavy metal enrichment in studied sediments was conducted by using: determination of total metal content, sequential extraction procedure for the fractionation of studied elements, quantification of the metal enrichment degree in the sediments by calculating geo-accumulation indices, determination of actual and potential element availability and application of BRAI index for the assessment of heavy metal bioavailability. The sediments were found to be contaminated by heavy metals to various extents, mostly with Cd, Cu, and Zn. The significant variation in heavy metal distribution among samples collected in this large region, encompassing all Serbian watersheds, suggests the selective contamination of sediments by heavy metals. Elevated concentrations of elements in most cases were detected in samples of river sediments, since artificial lake reservoirs are usually built in rural areas, where the less anthropogenic pollution. Rivers often flow through the towns and these water basins less or more loaded micronutrients, toxic substances, organic or inorganic, waste materials, depending on the species and type of industrial processes that are often without the necessary technological and mandatory treatment directly discharged into them. Due to the potential risk of heavy metal pollution in studied sediments, pollution prevention and control measurements seems necessary, especially in areas where we found increased levels of these elements.

Comparative study on the sensitivity of turions and active fronds of giant duckweed (Spirodela polyrhiza (L.) Schleiden) to heavy metal treatments.

PubMed

Oláh, Viktor; Hepp, Anna; Mészáros, Ilona

2015-08-01

Standard ecotoxicological test procedures use only active forms of aquatic plants. The potential effects of toxicants on vegetative propagules, which play an important role in the survival of several aquatic plant species, is not well understood. Because turion-like resting propagules overwinter on the water bottom in temperate regions, they could be exposed to contaminants for longer periods than active plants. Due to its turion producing capability, giant duckweed (Spirodela polyrhiza) is widely used in studying morphogenesis, dormancy, and activation mechanisms in plants. It is also suitable for ecotoxicological purposes. The present work aims to compare the growth inhibition sensitivity of active (normal frond) and overwintering (turion) forms of S. polyrhiza to concentrations of nickel (Ni), cadmium (Cd) and hexavalent chromium (Cr) ranging from 0 to 100mgL(-1). The results indicated that in general, resting turions have higher heavy metal tolerance than active fronds. Cd proved to be the most toxic heavy metal to S. polyrhiza active frond cultures because it induced rapid turion formation. In contrast, the toxicity of Ni and Cr were found to be similar but lower than the effects of Cd. Cr treatments up to 10mgL(-1) did not result in any future negative effects on turion activation. Turions did not survive heavy metal treatments at higher concentrations of Cr. Cd and Ni treatments affected both the floating-up and germination of turions but did not significantly affect the vigor of sprouts. Higher concentrations (of 100mgL(-1)) Cd completely inhibited germination. Copyright © 2015 Elsevier Ltd. All rights reserved.

Contamination by persistent toxic substances in surface sediment of urban rivers in Chaohu City, China.

PubMed

Li, Feipeng; Zhang, Haiping; Meng, Xiangzhou; Chen, Ling; Yin, Daqiang

2012-01-01

The concentration and spatial distribution of persistent toxic substances (PTS) in the river sediment in Chaohu City, China were investigated. A total of nine surface sediments were collected and the selected PTS pollutants including six heavy metals and nineteen polybrominated diphenyl ethers (PBDEs) were analyzed. The mean heavy metal concentrations (in mg/kg, dry weight) ranged within 0.18-1.53 (Hg), 50.08-200.18 (Cu), 118.70-313.65 (Zn), 50.77-310.85 (Cr), 37.12-92.72 (Pb) and 13.29-197.24 (As), and Cu, Zn and As have been regarded as the main metal pollutants. The levels of PBDEs (1.2-12.1 ng/g) and BDE-209 (2.4-30.5 ng/g) were at the middle level of the global range. BDE-209 was the predominant congener (67.0%-85.7%), which agrees with the fact that technical deca-BDE mixtures are the dominant PBDE formulation in China. The relative high level of PTS pollutants in the western part of the city is probably owing to the intensive agricultural activities and lack of sewerage system there. The ecological risk assessment with the sediment quality guidelines (SOGs) indicates that the urban river sediments in the city have been heavily contaminated by heavy metals with probable ecotoxicological impacts on freshwater organisms and the main toxic pollutants are Hg and As. The results of current study imply that the city, and perhaps many other small cities in China as well, requires immediate pollution control measures with emphasis on not only conventional organic pollutants but also on PTS such as heavy metals and PBDEs.

Synthesis of organically templated nanoporous tin (II/IV) phosphate for radionuclide and metal sequestration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wellman, Dawn M.; Mattigod, Shas V.; Parker, Kent E.

2006-03-20

Nanoporous tin (II/IV) phosphate materials, with spherical morphology, have been synthesized using cetyltrimethylammonium chloride (CH3(CH2)15N(CH3)3Cl) as the surfactant. The structure of the material is stable at 500°C; however, partial oxidation of the material occurs with redox conversion of Sn2+ to Sn4+, resulting in a mixed Sn(II)/ Sn(IV) material. Preliminary batch contact studies were conducted to assess the effectiveness of nanoporous tin phosphate, NP-SnPO, in sequestering redox sensitive metals and radionuclides, technetium(VII), neptunium(V), thorium(IV), and a toxic metal, chromium(VI), from aqueous matrices. Results indicate tin (II) phosphate removed > 95% of all contaminants investigated from solution.

Associations of urban environmental pollution with health-related physiological traits in a free-living bird species.

PubMed

Bauerová, Petra; Vinklerová, Jitka; Hraníček, Jakub; Čorba, Vojtěch; Vojtek, Libor; Svobodová, Jana; Vinkler, Michal

2017-12-01

Urban environmental pollution results in contamination of the tissues of synanthropic organisms by toxic trace elements with potential impacts on human health. Passerine birds may serve as convenient indicators of such contamination. In this study we investigated the effect of blood and plumage contamination with heavy metals (lead Pb, cadmium Cd, copper Cu, chromium Cr) and arsenic metalloid (As) on condition, health and ornamental colour in free-living great tit (Parus major) males from 13 cities across the Czech Republic (EU), mist netted during the early breading season (April-May). Our results showed a significant association of heavy metal tissue contamination with immune function, namely leukocyte composition in the avian blood circulation. High heavy metal contamination in bird feathers was linked to a high heterophil/lymphocyte (H/L) ratio, indicating long-term stress in individuals inhabiting heavily polluted environments. In contrast, males with higher concentrations of heavy metals in blood had a lower H/L ratio, assumingly due to the direct toxicity of heavy metals in certain cell types. This is also supported by traits indicative of anaemia-like haemolytic conditions (decreased absolute erythrocyte count) and increased haematopoiesis (a tendency for increased frequencies of immature erythrocytes). We did not find any association of heavy metal contamination with the bacteriolytic activity of plasma complement, feather growth or ornamentation (black breast stripe area and yellow colouration). There was no significant relationship between heavy metal contamination in blood or feathers and PM 10 pollution at the study sites. Our correlational study is the first to show on a large geographic scale that despite strict European air pollution regulations and regular monitoring that have allowed general improvements in atmospheric contamination, non-degradable heavy metals persistently contaminate animal blood and feathers in anthropogenic environments at levels that may have subclinical yet physiological effects with varied influence on health. Copyright © 2017 Elsevier B.V. All rights reserved.

Sodium chloride toxicity and the cellular basis of salt tolerance in halophytes

PubMed Central

Flowers, Timothy J.; Munns, Rana; Colmer, Timothy D.

2015-01-01

Background Halophytes are the flora of saline soils. They adjust osmotically to soil salinity by accumulating ions and sequestering the vast majority of these (generally Na+ and Cl−) in vacuoles, while in the cytoplasm organic solutes are accumulated to prevent adverse effects on metabolism. At high salinities, however, growth is inhibited. Possible causes are: toxicity to metabolism of Na+ and/or Cl− in the cytoplasm; insufficient osmotic adjustment resulting in reduced net photosynthesis because of stomatal closure; reduced turgor for expansion growth; adverse cellular water relations if ions build up in the apoplast (cell walls) of leaves; diversion of energy needed to maintain solute homeostasis; sub-optimal levels of K+ (or other mineral nutrients) required for maintaining enzyme activities; possible damage from reactive oxygen species; or changes in hormonal concentrations. Scope This review discusses the evidence for Na+ and Cl− toxicity and the concept of tissue tolerance in relation to halophytes. Conclusions The data reviewed here suggest that halophytes tolerate cytoplasmic Na+ and Cl− concentrations of 100–200 mm, but whether these ions ever reach toxic concentrations that inhibit metabolism in the cytoplasm or cause death is unknown. Measurements of ion concentrations in the cytosol of various cell types for contrasting species and growth conditions are needed. Future work should also focus on the properties of the tonoplast that enable ion accumulation and prevent ion leakage, such as the special properties of ion transporters and of the lipids that determine membrane permeability. PMID:25466549

Determination of Trace Metals, Moisture, pH and Assessment of Potential Toxicity of Selected Smokeless Tobacco Products

PubMed Central

Prabhakar, V.; Jayakrishnan, G.; Nair, S. V.; Ranganathan, B.

2013-01-01

The characterization and classification of smokeless tobacco products has been a continuously evolving process. This is based on a number of different parameters like nicotine content, moisture content, amount of heavy metals, pH, and in vitro cytotoxicity assays. Their contexts often vary between countries, research institutions, and legal requirements. The categorisation of these products is quite challenging due to the diffused sample sizes, diverse array of branded products on offer, and the absence of a centralized manufacturing facility. This study aims at a systematic classification of 10 smokeless tobacco product samples from the retail market based on their potential toxicity upon long-term use. The estimation of potential toxicity follows a well-established method that employs the concentration of toxic metals in the different samples. The potential toxicity as well as heavy metal concentrations of the smokeless tobacco products analysed was found to be much higher than acceptable limits. For instance, the levels of lead, cadmium, copper and zinc of 2.5, 1, 4 and 23 ppm, respectively, are well above their recommended limits. The results from the study indicate that chronic use of smokeless tobacco products is a significant health risk, especially in the vulnerable population. Further studies of this nature will help establish a toxicological fingerprint on the diverse class of products that floods the market now. PMID:24082341

The Use of Stimulable Bioluminescence from Marine Dinoflagellates as a Means of Detecting Toxicity in the Marine Environment

DTIC Science & Technology

1993-04-01

measure the acute and sublethal effects of heavy metals ( tributyltin , copper, and zinc) and storm drain effluent on the light output from marine...heavy metals ( tributyltin , copper, and zinc) and storm drain effluent on the light output from marine bioluminescent dinoflagellates (Pyrocystis...pentahydrate and zinc sulfate heptahydrate (Aldrich Chemical Co.); tributyltin chloride (Aldrich Chemical Co.); American Society for Testing and Materials

Exploiting the genetic and biochemical capacities of bacteria for the remediation of heavy metal pollution.

PubMed

Valls, Marc; de Lorenzo, Víctor

2002-11-01

The threat of heavy metal pollution to public health and wildlife has led to an increased interest in developing systems that can remove or neutralise its toxic effects in soil, sediments and wastewater. Unlike organic contaminants, which can be degraded to harmless chemical species, heavy metals cannot be destroyed. Remediating the pollution they cause can therefore only be envisioned as their immobilisation in a non-bioavailable form, or their re-speciation into less toxic forms. While these approaches do not solve the problem altogether, they do help to protect afflicted sites from noxious effects and isolate the contaminants as a contained and sometimes recyclable residue. This review outlines the most important bacterial phenotypes and properties that are (or could be) instrumental in heavy metal bioremediation, along with what is known of their genetic and biochemical background. A variety of instances are discussed in which valuable properties already present in certain strains can be combined or improved through state-of-the-art genetic engineering. In other cases, knowledge of metal-related reactions catalysed by some bacteria allows optimisation of the desired process by altering the physicochemical conditions of the contaminated area. The combination of genetic engineering of the bacterial catalysts with judicious eco-engineering of the polluted sites will be of paramount importance in future bioremediation strategies.

Multielemental analysis of Migori (Southwest, Kenya) artisanal gold mine ores and sediments by EDX-ray fluorescence technique: implications of occupational exposure and environmental impact.

PubMed

Odumo, O B; Mustapha, A O; Patel, J P; Angeyo, H K

2011-05-01

The results of heavy element profiling of the gold ores and sediments associated with the artisanal gold mining activities of the Migori gold belt of Southwestern Nyanza, Kenya, were reported in this paper. The analysis was made to assess the occupational exposure of the miners as well as to investigate the environmental impact of toxic heavy metals. Gold ores and sediments from the artisanal gold processing were sampled in four artisanal gold mining areas: Osiri A, Osiri B, Mikei and Macalder (Makalda) and analyzed for heavy elemental content using (109)Cd radioisotope excited EDXRF spectrometry technique. Analysis consisted of direct irradiating of sample pellets. The concentrations of major elements detected were: titanium (711.41-10,766.67 mg/kg); cobalt (82.65-1,010.00 mg/kg); zinc (29.90-63,210 mg/kg); arsenic (29.30-8,246.59 mg/kg); gold (14.07-73.48 mg/kg); lead (16.31-14,999.40 mg/kg) and mercury (16.10-149.93 mg/kg). The average concentration of the heavy toxic metals i.e. arsenic, lead, titanium and zinc were found to be above 50 mg/Kg as recommended by World Health Organization. © Springer Science+Business Media, LLC 2011

Heavy metals analysis and quality assessment in drinking water - Khorramabad city, Iran.

PubMed

Ghaderpoori, Mansour; Kamarehie, Bahram; Jafari, Ali; Ghaderpoury, Afshin; Karami, Mohammadamin

2018-02-01

Continuous monitoring of drinking water quality is essential in terms of heavy metals and toxic substances. The general objective of this study were to determine the concentration of heavy metals in drinking water of Khorramabad city and to determine the water quality indices (The heavy metal pollution index and heavy metal evaluation index). According to the city map, 45 points were selected for drinking water sampling through the city distribution system. The results of this study showed that the average concentration of heavy metals such as Zn, Pb, Cd, Cr, and Cu were 47.01 μg/l, 3.2 μg/l, 0.42 μg/l, 5.08 μg/l, and 6.79 μg/l, respectively. The HPI and HEI (water quality indices) for Zn, Pb, Cd, Cr, and Cu were 46.58, 46.58, respectively. According to the indices, the city drinking water quality is good in terms of heavy metals.

Influence of Heavy Metal Stress On Water Regime of A Model Forest Ecosystem

NASA Astrophysics Data System (ADS)

Menon, M.; Abbaspour, K. C.; Schulin, R.

Among various toxic substances that contaminate the soil, the effects of heavy metals are particularly severe on all aspects of soil-plant system. The Swiss Federal Institute for Forest Snow and Land Research (WSL) is addressing comprehensively the issue of heavy metal toxicity in a forest ecosystem in a project titled Sfrom cell to treeT. As & cedil; part of the above project an investigation is being carried out to evaluate the impact of heavy metal stress on water regime of a young forest ecosystem grown in sixteen open top lysimeters. The factorial treatments of the lysimeters include variations of rainwa- ter acidity (acidic, neutral), subsoil type (acidic, calcareous), and heavy metal con- centration (with and without heavy metals in the top 20 cm). Filling of lysimeters was completed in November 1999. Each model ecosystem was planted in spring 2000 with the same collection of trees and herbaceous plants. Each lysimeters is equipped with tensiometers for monitoring of pressure head, time domain reflectometry for moni- toring of water content, and sprinkler devices for application of controlled irrigation. Drainage water data are measured regularly from the canisters installed at the bot- tom of lysimeters and evapotranspiration is calculated through water balancing. Our preliminary analyses of the data shoed the following results. Weekly data collected from May to October 2001 indicated higher amount of percolating water in acidic soil compared to the neutral soil due to textural difference. At 12 cm depth in both soils, control and acidic rain showed lower water potential than heavy metal and combina- tion of acidic rain with heavy metal treatments. In lower depths, water potential did not show much difference between treatments. Water contents showed differences be- tween treatments in the upper part of the profile where the soil is contaminated with heavy metals. Higher water content was observed in heavy metal treatment at 0-25 cm depth than 25-50 cm depth. This indicates higher root activity at deeper soil profile where heavy metal is not present. The overall results indicated differences in water regime of the heavy metal-treated soils. We expect this difference to be more signifi- cant in the next years as trees grow larger and exert a stronger water demand.

Control of Toxic Chemicals in Puget Sound, Phase 3: Study Of Atmospheric Deposition of Air Toxics to the Surface of Puget Sound

DTIC Science & Technology

2007-01-01

deposition directly to Puget Sound was an important source of PAHs, polybrominated diphenyl ethers (PBDEs), and heavy metals . In most cases, atmospheric...versus Atmospheric Fluxes ........................................................................66  PAH Source Apportionment ...temperature inversions) on air quality during the wet season. A semi-quantitative apportionment study permitted a first-order characterization of source

Chronic Manganese Toxicity Associated with Voltage-Gated Potassium Channel Complex Antibodies in a Relapsing Neuropsychiatric Disorder

PubMed Central

Ho, Cyrus S.H.; Quek, Amy M.L.

2018-01-01

Heavy metal poisoning is a rare but important cause of encephalopathy. Manganese (Mn) toxicity is especially rare in the modern world, and clinicians’ lack of recognition of its neuropsychiatric manifestations can lead to misdiagnosis and mismanagement. We describe the case of a man who presented with recurrent episodes of confusion, psychosis, dystonic limb movement and cognitive impairment and was initially diagnosed with anti-voltage-gated potassium channel (VGKC) complex limbic encephalitis in view of previous positive autoantibodies. His failure to respond to immunotherapy prompted testing for heavy metal poisoning, which was positive for Mn. This is the first report to examine an association between Mn and VGKC antibodies and the effects of Mn on functional brain activity using functional near-infrared spectroscopy (fNIRS). PMID:29669989

Chronic Manganese Toxicity Associated with Voltage-Gated Potassium Channel Complex Antibodies in a Relapsing Neuropsychiatric Disorder.

PubMed

Ho, Cyrus S H; Ho, Roger C M; Quek, Amy M L

2018-04-18

Heavy metal poisoning is a rare but important cause of encephalopathy. Manganese (Mn) toxicity is especially rare in the modern world, and clinicians’ lack of recognition of its neuropsychiatric manifestations can lead to misdiagnosis and mismanagement. We describe the case of a man who presented with recurrent episodes of confusion, psychosis, dystonic limb movement and cognitive impairment and was initially diagnosed with anti-voltage-gated potassium channel (VGKC) complex limbic encephalitis in view of previous positive autoantibodies. His failure to respond to immunotherapy prompted testing for heavy metal poisoning, which was positive for Mn. This is the first report to examine an association between Mn and VGKC antibodies and the effects of Mn on functional brain activity using functional near-infrared spectroscopy (fNIRS).

Ultrapure laser-synthesized Si-based nanomaterials for biomedical applications: in vivo assessment of safety and biodistribution

PubMed Central

Baati, Tarek; Al-Kattan, Ahmed; Esteve, Marie-Anne; Njim, Leila; Ryabchikov, Yury; Chaspoul, Florence; Hammami, Mohamed; Sentis, Marc; Kabashin, Andrei V.; Braguer, Diane

2016-01-01

Si/SiOx nanoparticles (NPs) produced by laser ablation in deionized water or aqueous biocompatible solutions present a novel extremely promising object for biomedical applications, but the interaction of these NPs with biological systems has not yet been systematically examined. Here, we present the first comprehensive study of biodistribution, biodegradability and toxicity of laser-synthesized Si-SiOx nanoparticles using a small animal model. Despite a relatively high dose of Si-NPs (20 mg/kg) administered intravenously in mice, all controlled parameters (serum, enzymatic, histological etc.) were found to be within safe limits 3 h, 24 h, 48 h and 7 days after the administration. We also determined that the nanoparticles are rapidly sequestered by the liver and spleen, then further biodegraded and directly eliminated in urine without any toxicity effects. Finally, we found that intracellular accumulation of Si-NPs does not induce any oxidative stress damage. Our results evidence a huge potential in using these safe and biodegradable NPs in biomedical applications, in particular as vectors, contrast agents and sensitizers in cancer therapy and diagnostics (theranostics). PMID:27151839

Ultrapure laser-synthesized Si-based nanomaterials for biomedical applications: in vivo assessment of safety and biodistribution

NASA Astrophysics Data System (ADS)

Baati, Tarek; Al-Kattan, Ahmed; Esteve, Marie-Anne; Njim, Leila; Ryabchikov, Yury; Chaspoul, Florence; Hammami, Mohamed; Sentis, Marc; Kabashin, Andrei V.; Braguer, Diane

2016-05-01

Si/SiOx nanoparticles (NPs) produced by laser ablation in deionized water or aqueous biocompatible solutions present a novel extremely promising object for biomedical applications, but the interaction of these NPs with biological systems has not yet been systematically examined. Here, we present the first comprehensive study of biodistribution, biodegradability and toxicity of laser-synthesized Si-SiOx nanoparticles using a small animal model. Despite a relatively high dose of Si-NPs (20 mg/kg) administered intravenously in mice, all controlled parameters (serum, enzymatic, histological etc.) were found to be within safe limits 3 h, 24 h, 48 h and 7 days after the administration. We also determined that the nanoparticles are rapidly sequestered by the liver and spleen, then further biodegraded and directly eliminated in urine without any toxicity effects. Finally, we found that intracellular accumulation of Si-NPs does not induce any oxidative stress damage. Our results evidence a huge potential in using these safe and biodegradable NPs in biomedical applications, in particular as vectors, contrast agents and sensitizers in cancer therapy and diagnostics (theranostics).

Silicon mitigates heavy metal stress by regulating P-type heavy metal ATPases, Oryza sativa low silicon genes, and endogenous phytohormones

PubMed Central

2014-01-01

Background Silicon (Si) application has been known to enhance the tolerance of plants against abiotic stresses. However, the protective mechanism of Si under heavy metals contamination is poorly understood. The aim of this study was to assess the role of Si in counteracting toxicity due to cadmium (Cd) and copper (Cu) in rice plants (Oryza sativa). Results Si significantly improved the growth and biomass of rice plants and reduced the toxic effects of Cd/Cu after different stress periods. Si treatment ameliorated root function and structure compared with non-treated rice plants, which suffered severe root damage. In the presence of Si, the Cd/Cu concentration was significantly lower in rice plants, and there was also a reduction in lipid peroxidation and fatty acid desaturation in plant tissues. The reduced uptake of metals in the roots modulated the signaling of phytohormones involved in responses to stress and host defense, such as abscisic acid, jasmonic acid, and salicylic acid. Furthermore, the low concentration of metals significantly down regulated the mRNA expression of enzymes encoding heavy metal transporters (OsHMA2 and OsHMA3) in Si-metal-treated rice plants. Genes responsible for Si transport (OsLSi1 and OsLSi2), showed a significant up-regulation of mRNA expression with Si treatment in rice plants. Conclusion The present study supports the active role of Si in the regulation of stresses from heavy metal exposure through changes in root morphology. PMID:24405887

Conditions for the formation and atmospheric dispersion of a toxic, heavy gas layer during thermal metamorphism of coal and evaporite deposits by sill intrusion

NASA Astrophysics Data System (ADS)

Storey, Michael; Hankin, Robin K. S.

2010-05-01

There is compelling evidence for massive discharge of volatiles, including toxic species, into the atmosphere at the end of the Permian. It has been argued that most of the gases were produced during thermal metamorphism of coal and evaporite deposits in the East Siberia Tunguska basin following sill intrusion (Retallack and Jahren, 2008; Svensen et al., 2009). The release of the volatiles has been proposed as a major cause of environmental and extinction events at the end of the Permian, with venting of carbon gases and halocarbons to the atmosphere leading to global warming and atmospheric ozone depletion (Svensen et al., 2009) Here we consider the conditions required for the formation and dispersion of toxic, heavier than air, gas plumes, made up of a mixture of CO2, CH4, H2S and SO2 and formed during the thermal metamorphism of C- and S- rich sediments. Dispersion models and density considerations within a range of CO2/CH4 ratios and volatile fluxes and temperatures, for gas discharge by both seepage and from vents, allow the possibility that following sill emplacement much of the vast East Siberia Tunguska basin was - at least intermittently - covered by a heavy, toxic gas layer that was unfavorable for life. Dispersion scenarios for a heavy gas layer beyond the Siberian region during end-Permian times will be presented. REFERENCES G. J. Retallack and A. H. Jahren, Methane release from igneous intrusion of coal during Late Permian extinction events, Journal of Geology, volume 116, 1-20, 2008 H. Svensen et al., Siberian gas venting and the end-Permian environmental crisis, Earth and Planetary Science Letters, volume 277, 490-500, 2009

[Monitoring early toxicity of heavy metals including Hg using a HSE-SEAP reporter gene].

PubMed

Yu, Zhan-Jiang; Yang, Qin; Yang, Xiao-Da; Wang, Kui

2006-08-01

To develop a cellular assay based on heat shock signal pathway and secreted alkaline phosphatase (SEAP) reporter gene for investigating/predicting the early toxicity of heavy metals on HeLa cells in Chinese traditional medicine (TCM). The pHSE-SEAP plasmid was transfected into HeLa cells to build a HSE-SEAP-HeLa cell model. For validation of the model, the transfected cells were treated by either heating at 42 degrees C for 1 h or incubated with 5 mol x L(-1) CdCl2 for 4 h. Then the cells were covered in complete DMEM culture medium for 48 h and the activity of SEAP (reflecting the cellular level of heat shock protein) in cultural supernatants was measured; meanwhile, cell viability was determined by MTT assays. In addition, the cells were treated by four mercury compounds, HgCl2, merthilate sodium, HgS and cinnabar at the sub-lethal concentrations (determined by MTT assays). Then the heat shock response was detected likewise. Significant level of secreted alkaline phosphatase (SEAP) was found in pHSE-SEAP transfected HeLa cells treated either by heating (42 degrees C) or incubating with CdCl2. The heat shock protein was induced by CdCl2 before decrease of cell viability was observed. All four mercury compounds induced heat shock response in both time and concentration-dependant manner. However, there were big differences among the mercury compounds, suggesting potential differences for early-stage toxicity in vivo. The pHSE-SEAP transfected HeLa cells respond effectively to heat shock and metal stresses, and therefore provide a practical and repeatable assay for investigating/predicting the early toxicity of heavy metals and mineral-containing drugs in TCM.

Cell surface engineering of microorganisms towards adsorption of heavy metals.

PubMed

Li, Peng-Song; Tao, Hu-Chun

2015-06-01

Heavy metal contamination has become a worldwide environmental concern due to its toxicity, non-degradability and food-chain bioaccumulation. Conventional physical and chemical treatment methods for heavy metal removal have disadvantages such as cost-intensiveness, incomplete removal, secondary pollution and the lack of metal specificity. Microbial biomass-based biosorption is one of the approaches gaining increasing attention because it is effective, cheap, and environmental friendly and can work well at low concentrations. To enhance the adsorption properties of microbial cells to heavy metal ions, the cell surface display of various metal-binding proteins/peptides have been performed using a cell surface engineering approach. The surface engineering of Gram-negative bacteria, Gram-positive bacteria and yeast towards the adsorption of heavy metals are reviewed in this article. The problems and future perspectives of this technology are discussed.

Biodegradation of asphalt by Garciaella petrolearia TERIG02 for viscosity reduction of heavy oil.

PubMed

Lavania, Meeta; Cheema, Simrita; Sarma, Priyangshu Manab; Mandal, Ajoy Kumar; Lal, Banwari

2012-02-01

Petroleum hydrocarbon is an important energy resource, but it is difficult to exploit due to the presence of dominated heavy constituents such as asphaltenes. In this study, viscosity reduction of Jodhpur heavy oil (2,637 cP at 50°C) has been carried out by the biodegradation of asphalt using a bacterial strain TERIG02. TERIG02 was isolated from sea buried oil pipeline known as Mumbai Uran trunk line (MUT) located on western coast of India and identified as Garciaella petrolearia by 16S rRNA full gene sequencing. TERIG02 showed 42% viscosity reduction when asphalt along with molasses was used as a sole carbon source compared to only asphalt (37%). The viscosity reduction by asphaltene degradation has been structurally characterized by Fourier transform infrared spectroscopy (FTIR). This strain also shows an additional preference to degrade toxic asphalt and aromatics compounds first unlike the other known strains. All these characteristics makes TERIG02 a potential candidate for enhanced oil recovery and a solution to degrading toxic aromatic compounds.

Effects of heavy metals on sea urchin embryo development. 1. Tracing the cause by the effects.

PubMed

Kobayashi, Naomasa; Okamura, Hideo

2004-06-01

The toxicity of the polluted waters originating from a disused lead mine was evaluated using both sea urchin bioassays and heavy metal analysis. Samples from three polluted waters (a seawater and two freshwaters) were collected from the mine area and one seawater sample was taken from a non-contaminated reference site. The test waters contained higher concentrations of heavy metals such as manganese, lead, cadmium, zinc, chromium, nickel, iron, and copper than did ambient seawater. The three test waters had inhibitory effects, in a dose-dependent manner, on the first cleavage of sea urchin embryos and on pluteus formation during the development. Some malformations, such as a radialized pluteus, exo-gastrula, and spaceship Apollo-like embryos were induced by the test waters without dilution. Zinc alone also induced the same anomaly. Zinc in the test seawater was ascertained as one of the metals that caused the anomalies, but not all of the toxicity was caused by zinc. It was speculated that interactive effects, involving zinc and possibly manganese and nickel, were occurring.

Laser-Induced Breakdown Spectroscopy for Rapid Discrimination of Heavy-Metal-Contaminated Seafood Tegillarca granosa

PubMed Central

Ji, Guoli; Ye, Pengchao; Shi, Yijian; Yuan, Leiming; Chen, Xiaojing; Yuan, Mingshun; Zhu, Dehua; Chen, Xi; Hu, Xinyu; Jiang, Jing

2017-01-01

Tegillarca granosa samples contaminated artificially by three kinds of toxic heavy metals including zinc (Zn), cadmium (Cd), and lead (Pb) were attempted to be distinguished using laser-induced breakdown spectroscopy (LIBS) technology and pattern recognition methods in this study. The measured spectra were firstly processed by a wavelet transform algorithm (WTA), then the generated characteristic information was subsequently expressed by an information gain algorithm (IGA). As a result, 30 variables obtained were used as input variables for three classifiers: partial least square discriminant analysis (PLS-DA), support vector machine (SVM), and random forest (RF), among which the RF model exhibited the best performance, with 93.3% discrimination accuracy among those classifiers. Besides, the extracted characteristic information was used to reconstruct the original spectra by inverse WTA, and the corresponding attribution of the reconstructed spectra was then discussed. This work indicates that the healthy shellfish samples of Tegillarca granosa could be distinguished from the toxic heavy-metal-contaminated ones by pattern recognition analysis combined with LIBS technology, which only requires minimal pretreatments. PMID:29149053

Chelate-assisted phytoextraction of heavy metals in a soil contaminated with a pyritic sludge.

PubMed

Peñalosa, Jesus Manuel; Carpena, Ramón O; Vázquez, Saúl; Agha, Ramsy; Granado, Ana; Sarro, María José; Esteban, Elvira

2007-05-25

The occurrence of many polluted areas as that affected by the accident of the Aznalcóllar pyrite mine has promoted phytoremediation as a technology able to reduce the risk of heavy metal contamination at low cost. White lupin plant has been considered a good candidate for phytoremediation. We studied the capacity of several complexing agents to improve the ability of white lupin for heavy metal phytoremediation in soils with multi-elemental pollution from acid pyritic sludge. Solution-soil interaction was studied and pot experiments with sludge-affected soil were carried out to this end. The interaction experiments indicated that EDTA and NTA were more efficient than malate and citrate in solubilizing metals (Fe, Mn, Cu, Zn, Cd), with minimum differences between EDTA and NTA. The pot trial showed that NTA was able to mobilize toxic elements from sludge-polluted soil and hence increasing their concentrations in plant (Mn, Cu, Zn, As, Cd). However, the NTA treatment promoted an increase of toxic elements concentrations, especially for As, Cd, Pb, in the lixiviates exceeding the maximum permissible levels, so a careful management of chelate is necessary.

The Heavy Metals in Agrosystems and Impact on Health and Quality of Life.

PubMed

Tutic, Adnan; Novakovic, Srecko; Lutovac, Mitar; Biocanin, Rade; Ketin, Sonja; Omerovic, Nusret

2015-06-15

The metal is a chemical element that conducts electricity well and heat, and the nonferrous metals builds cations and ionic bonds. Heavy metals include metals whose density is higher than 5 g/cm(3). The whole range of the metal is in the form of essential trace elements, essential for a number of functions in the human body, and its deficiency results in a lack of occurrence of a serious symptom. The best examples are anemia lack of iron, lack of chromium in diabetes, growth problems in lack of nickel. Other elements such as lead, cadmium, mercury, arsenic and molybdenum have been shown to exhibit large quantities of toxic effects. The paper examines the problem of heavy metals originating from agriculture on agroecosystems. This group of pollutants is considered the most important cause of degradation of soil quality, surface and groundwater and direct causal adverse effects on human and animal health. In order to complete the environmental monitoring of pollutants, these main categories, origins, and possible negative impacts of the basic principles of preventing their toxic effects were examined.

The Heavy Metals in Agrosystems and Impact on Health and Quality of Life

PubMed Central

Tutic, Adnan; Novakovic, Srecko; Lutovac, Mitar; Biocanin, Rade; Ketin, Sonja; Omerovic, Nusret

2015-01-01

The metal is a chemical element that conducts electricity well and heat, and the nonferrous metals builds cations and ionic bonds. Heavy metals include metals whose density is higher than 5 g/cm3. The whole range of the metal is in the form of essential trace elements, essential for a number of functions in the human body, and its deficiency results in a lack of occurrence of a serious symptom. The best examples are anemia lack of iron, lack of chromium in diabetes, growth problems in lack of nickel. Other elements such as lead, cadmium, mercury, arsenic and molybdenum have been shown to exhibit large quantities of toxic effects. The paper examines the problem of heavy metals originating from agriculture on agroecosystems. This group of pollutants is considered the most important cause of degradation of soil quality, surface and groundwater and direct causal adverse effects on human and animal health. In order to complete the environmental monitoring of pollutants, these main categories, origins, and possible negative impacts of the basic principles of preventing their toxic effects were examined. PMID:27275249

Leachability of Arsenic and Heavy Metals from Mine Tailings of Abandoned Metal Mines

PubMed Central

Lim, Mihee; Han, Gi-Chun; Ahn, Ji-Whan; You, Kwang-Suk; Kim, Hyung-Seok

2009-01-01

Mine tailings from an abandoned metal mine in Korea contained high concentrations of arsenic (As) and heavy metals [e.g., As: 67,336, Fe: 137,180, Cu: 764, Pb: 3,572, and Zn: 12,420 (mg/kg)]. US EPA method 6010 was an effective method for analyzing total arsenic and heavy metals concentrations. Arsenic in the mine tailings showed a high residual fraction of 89% by a sequential extraction. In Toxicity Characteristic Leaching Procedure (TCLP) and Korean Standard Leaching Test (KSLT), leaching concentrations of arsenic and heavy metals were very low [e.g., As (mg/L): 0.4 for TCLP and 0.2 for KSLT; cf. As criteria (mg/L): 5.0 for TCLP and 1.5 for KSLT]. PMID:20049231

Head and neck cancer due to heavy metal exposure via tobacco smoking and professional exposure: A review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khlifi, Rim, E-mail: rimkhlifi@yahoo.fr; Hamza-Chaffai, Amel

Chronic exposures to heavy metals via tobacco smoking and professional exposure may increase the risk of head and neck cancer, although the epidemiologic evidence is limited by problems of low study power and inadequate adjustment for tobacco and professional exposure use. Numerous scientific reviews have examined the association of various heavy metals exposure with respiratory cancer as well as other cancer types, but few have been published on head and neck cancer. The purpose of this paper, therefore, is to review the head and neck tract cancer-related data on exposure to heavy metals via smoking and working exposure and tomore » study the major mechanisms underlying some toxic metals carcinogenesis.« less

Toxicity of formulants and heavy metals in glyphosate-based herbicides and other pesticides.

PubMed

Defarge, N; Spiroux de Vendômois, J; Séralini, G E

2018-01-01

The major pesticides of the world are glyphosate-based herbicides (GBH), and their toxicity is highly debated. To understand their mode of action, the comparative herbicidal and toxicological effects of glyphosate (G) alone and 14 of its formulations were studied in this work, as a model for pesticides. GBH are mixtures of water, with commonly 36-48% G claimed as the active principle. As with other pesticides, 10-20% of GBH consist of chemical formulants. We previously identified these by mass spectrometry and found them to be mainly families of petroleum-based oxidized molecules, such as POEA, and other contaminants. We exposed plants and human cells to the components of formulations, both mixed and separately, and measured toxicity and human cellular endocrine disruption below the direct toxicity experimentally measured threshold. G was only slightly toxic on plants at the recommended dilutions in agriculture, in contrast with the general belief. In the short term, the strong herbicidal and toxic properties of its formulations were exerted by the POEA formulant family alone. The toxic effects and endocrine disrupting properties of the formulations were mostly due to the formulants and not to G. In this work, we also identified by mass spectrometry the heavy metals arsenic, chromium, cobalt, lead and nickel, which are known to be toxic and endocrine disruptors, as contaminants in 22 pesticides, including 11 G-based ones. This could also explain some of the adverse effects of the pesticides. In in vivo chronic regulatory experiments that are used to establish the acceptable daily intakes of pesticides, G or other declared active ingredients in pesticides are assessed alone, without the formulants. Considering these new data, this assessment method appears insufficient to ensure safety. These results, taken together, shed a new light on the toxicity of these major herbicides and of pesticides in general.

38 CFR 4.115b - Ratings of the genitourinary system-diagnoses.

Code of Federal Regulations, 2011 CFR

2011-07-01

... neoplasms of the genitourinary system 100 Note—Following the cessation of surgical, X-ray, antineoplastic.... 7535Toxic nephropathy (antibotics, radiocontrast agents, nonsteroidal anti-inflammatory agents, heavy metals...

38 CFR 4.115b - Ratings of the genitourinary system-diagnoses.

Code of Federal Regulations, 2010 CFR

2010-07-01

... neoplasms of the genitourinary system 100 Note—Following the cessation of surgical, X-ray, antineoplastic.... 7535Toxic nephropathy (antibotics, radiocontrast agents, nonsteroidal anti-inflammatory agents, heavy metals...

Fractionation and leachability of heavy metals from aged and recent Zn metallurgical leach residues from the Três Marias zinc plant (Minas Gerais, Brazil).

PubMed

Sethurajan, Manivannan; Huguenot, David; Lens, Piet N L; Horn, Heinrich A; Figueiredo, Luiz H A; van Hullebusch, Eric D

2016-04-01

Various mineral processing operations to produce pure metals from mineral ores generate sludges, residues, and other unwanted by-products/wastes. As a general practice, these wastes are either stored in a reservoir or disposed in the surrounding of mining/smelting areas, which might cause adverse environmental impacts. Therefore, it is important to understand the various characteristics like heavy metal leaching features and potential toxicity of these metallurgical wastes. In this study, zinc plant leach residues (ZLRs) were collected from a currently operating Zn metallurgical industry located in Minas Gerais (Brazil) and investigated for their potential toxicity, fractionation, and leachability. Three different ZLR samples (ZLR1, ZLR2, and ZLR3) were collected, based on their age of production and deposition. They mainly consisted of Fe (6-11.5 %), Zn (2.5 to 5.0 %), and Pb (1.5 to 2.5 %) and minor concentrations of Al, Cd, Cu, and Mn, depending on the sample age. Toxicity Characteristic Leaching Procedure (TCLP) results revealed that these wastes are hazardous for the environment. Accelerated Community Bureau of Reference (BCR) sequential extraction clearly showed that potentially toxic heavy metals such as Cd, Cu, Pb, and Zn can be released into the environment in high quantities under mild acidic conditions. The results of the liquid-solid partitioning as a function of pH showed that pH plays an important role in the leachability of metals from these residues. At low pH (pH 2.5), high concentrations of metals can be leached: 67, 25, and 7 % of Zn can be leached from leach residues ZLR1, ZLR2, and ZLR3, respectively. The release of metals decreased with increasing pH. Geochemical modeling of the pH-dependent leaching was also performed to determine which geochemical process controls the leachability/solubility of the heavy metals. This study showed that the studied ZLRs contain significant concentrations of non-residual extractable fractions of Zn and can be seen as a potential secondary resource for Zn.

Development of an accelerated leaching method for incineration bottom ash correlated to toxicity characteristic leaching protocol.

PubMed

Lin, Shengxuan; Zhou, Xuedong; Ge, Liya; Ng, Sum Huan; Zhou, Xiaodong; Chang, Victor Wei-Chung

2016-10-01

Heavy metals and some metalloids are the most significant inorganic contaminants specified in toxicity characteristic leaching procedure (TCLP) in determining the safety of landfills or further utilization. As a consequence, a great deal of efforts had been made on the development of miniaturized analytical devices, such as Microchip Electrophoresis (ME) and μTAS for on-site testing of heavy metals and metalloids to prevent spreading of those pollutants or decrease the reutilization period of waste materials such as incineration bottom ash. However, the bottleneck lied in the long and tedious conventional TCLP that requires 18 h of leaching. Without accelerating the TCLP process, the on-site testing of the waste material leachates was impossible. In this study, therefore, a new accelerated leaching method (ALM) combining ultrasonic assisted leaching with tumbling was developed to reduce the total leaching time from 18 h to 30 min. After leaching, the concentrations of heavy metals and metalloids were determined with ICP-MS or ICP-optical emission spectroscopy. No statistical significance between ALM and TCLP was observed for most heavy metals (i.e., cobalt, manganese, mercury, molybdenum, nickel, silver, strontium, and tin) and metalloids (i.e., arsenic and selenium). For the heavy metals with statistical significance, correlation factors derived between ALM and TCLP were 0.56, 0.20, 0.037, and 0.019 for barium, cadmium, chromium, and lead, respectively. Combined with appropriate analytical techniques (e.g., ME), the ALM can be applied to rapidly prepare the incineration bottom ash samples as well as other environmental samples for on-site determination of heavy metals and metalloids. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Increased Tolerance to Heavy Metals Exhibited by Swarming Bacteria

NASA Astrophysics Data System (ADS)

Anyan, M.; Shrout, J. D.

2014-12-01

Pseudomonas aeruginosa is a ubiquitous, Gram-negative bacterium that utilizes several different modes of motility to colonize surfaces, including swarming, which is the coordinated movement of cells over surfaces in groups. Swarming facilitates surface colonization and biofilm development for P. aeruginosa, and it is known that swarming behavior is influenced by changes in nutrient composition and surface moisture. To understand the fate and cycling of heavy metals in the environment, it is important to understand the interaction and toxicity of these metals upon bacteria. While previous studies have shown surface-attached bacterial biofilms to be highly resistant to heavy metal toxicity, little is known about the influence of heavy metals upon surface motile bacteria and developing biofilms. Using a combination of laboratory assays we examined differences in bacterial behavior in response to two metals, Cd and Ni. We find that surface swarming bacteria are able to grow on 4x and 2.5x more Cd and Ni, respectively, than planktonic cells (i.e., test tube cultures). P. aeruginosa was able to swarm in the presence ≤0.051mM Ni and ≤0.045mM Cd. To investigate the bioavailability of metals to bacteria growing under our examined conditions, we separated cell and supernatant fractions of P. aeruginosa cultures, and used ICP-MS techniques to measure Cd and Ni sorption. A greater percentage of Cd than Ni was sorbed by both cells and supernatant (which contains rhamnolipid, a surfactant known to sorb some metals and improve swarming). While we show that cell products such as rhamnolipid bind heavy metals (as expected) and should limit metal bioavailability, our results suggest at least one additional mechanism (as yet undetermined) that promotes cell survival during swarming in the presence of these heavy metals.

Influence of taxa, trophic level, and location on bioaccumulation of toxic metals in bird's feathers: a preliminary biomonitoring study using multiple bird species from Pakistan.

PubMed

Abbasi, Naeem Akhtar; Jaspers, Veerle Leontina Bernard; Chaudhry, Muhammad Jamshed Iqbal; Ali, Sakhawat; Malik, Riffat Naseem

2015-02-01

Increasing concentrations of heavy metals in the environment and their effects on ecosystems and biota is still an imminent threat, particularly in developing parts of the globe. The aim of the present study was to screen the heavy metal concentrations in multiple bird species across Pakistan and to preliminary evaluate the influence of taxa, trophic level, and geographical location on heavy metal accumulation in various bird species. For this purpose, we measured the concentration of 9 heavy metals (Pb, Cd, Cr, Ni, Co, Cu, Fe, Zn and Mn) in feathers of 48 bird species from different localities in Pakistan. Species exhibited heterogeneous levels of heavy metals in feathers with marked inter and intra specific variations. Mean concentrations of studied metals in feathers followed the trend Fe>Zn>Cu>Pb>Mn>Cr>Ni>Co>Cd. Species belonging to closely related taxa (families) showed comparable metal concentrations in their feathers, inferring potential phylogenetic similarities in metal exposure or accumulation. In general, concentrations of metals were greatest in carnivorous species followed by omnivorous and insectivorous birds, and granivores showing minimal levels (p<0.000). Furthermore, concentrations of metals varied significantly between locations (p<0.000) exhibiting highest concentrations in Punjab province and Baluchistan, probably due to higher industrial and agricultural activity and runoff, respectively. With certain limitation, influence of trophic level, taxonomic affiliation and sampling location of birds on toxic metal accumulation was also statistically corroborated through principal component analysis (PCA). This study highlights that despite restricted emissions, heavy metals persist in the local environment and may pose elevated risks for the studied bird species in Pakistan. Copyright © 2014 Elsevier Ltd. All rights reserved.

Examination of Heavy Metals and Particulate Matter Exposures and Effects in Susceptible Wards in the Washington, D.C. Region

NASA Astrophysics Data System (ADS)

Greene, N. A.; Morris, D. R.

2004-05-01

The District of Columbia has one of the greatest health disparities of cancer in the nation and ranks seventh highest as one of the unhealthiest places to live due to poor air quality (EPA Report, 1999). Also, a 1999 report from the Centers for Disease Control stated that the District had the highest overall rate of cancer incidence in the nation. Particulate matter is one of the major contributors to pollution in the environment. Quite often particulate matter is composed of toxic materials including heavy metals, pesticides, and spores. In some cases, the heavy metal particulates are considered carcinogenic. They are typically characterized as particles with diameters smaller than 1 m and are easily deposited into the alveolar regions of the human lungs, which can impose threatening health risks. In this study, I will design and execute an environmental exposure assessment for PM2.5, PM10, and heavy metals like chromium, as well as lead, cadmium and arsenic, in four observed wards of Washington, DC. Most interestingly, spatial distributions of both aerosols and heavy metals will be characterized as a function of size and mass properties. This will formulate a limited climatology of both types of particulate matter and selected heavy metals for specific regions within the District of Columbia. This dataset will further be related to epidemiological data and health outcomes for the observed areas of study. The essence of this study lies in its notoriety as the first to generate a dataset that focuses on toxic air pollutants in particular wards and may be utilized in various aspects of public health.

Correlation of Lethal Concentrations of Heavy Metals with Tissue Levels of Earthworms

DTIC Science & Technology

1988-08-01

mentioned in the contract i.e. mercury , arsenic, ’cadmium and copper. We will find out the 50 % lethal concentrations (LC50) and the smallest...concentrations, blanks, and background worm stock has been limited to copper and cadmium. In fact, mercury and arsenic request special analytical device...the other boxes but without toxic components. Contaminants to study are heavy metals : cadmium, copper and mercury , and arsenic. We chose following

Chemical and toxicological evaluation of underground coal gasification (UCG) effluents. The coal rank effect.

PubMed

Kapusta, Krzysztof; Stańczyk, Krzysztof

2015-02-01

The effect of coal rank on the composition and toxicity of water effluents resulting from two underground coal gasification experiments with distinct coal samples (lignite and hard coal) was investigated. A broad range of organic and inorganic parameters was determined in the sampled condensates. The physicochemical tests were supplemented by toxicity bioassays based on the luminescent bacteria Vibrio fischeri as the test organism. The principal component analysis and Pearson correlation analysis were adopted to assist in the interpretation of the raw experimental data, and the multiple regression statistical method was subsequently employed to enable predictions of the toxicity based on the values of the selected parameters. Significant differences in the qualitative and quantitative description of the contamination profiles were identified for both types of coal under study. Independent of the coal rank, the most characteristic organic components of the studied condensates were phenols, naphthalene and benzene. In the inorganic array, ammonia, sulphates and selected heavy metals and metalloids were identified as the dominant constituents. Except for benzene with its alkyl homologues (BTEX), selected polycyclic aromatic hydrocarbons (PAHs), zinc and selenium, the values of the remaining parameters were considerably greater for the hard coal condensates. The studies revealed that all of the tested UCG condensates were extremely toxic to V. fischeri; however, the average toxicity level for the hard coal condensates was approximately 56% higher than that obtained for the lignite. The statistical analysis provided results supporting that the toxicity of the condensates was most positively correlated with the concentrations of free ammonia, phenols and certain heavy metals. Copyright © 2014 Elsevier Inc. All rights reserved.

Toxicity of irradiated advanced heavy water reactor fuels.

PubMed

Priest, N D; Richardson, R B; Edwards, G W R

2013-02-01

The good neutron economy and online refueling capability of the CANDU® heavy water moderated reactor (HWR) enable it to use many different fuels such as low enriched uranium (LEU), plutonium, or thorium, in addition to its traditional natural uranium (NU) fuel. The toxicity and radiological protection methods for these proposed fuels, unlike those for NU, are not well established. This study uses software to compare the fuel composition and toxicity of irradiated NU fuel against those of two irradiated advanced HWR fuel bundles as a function of post-irradiation time. The first bundle investigated is a CANFLEX® low void reactor fuel (LVRF), of which only the dysprosium-poisoned central element, and not the outer 42 LEU elements, is specifically analyzed. The second bundle investigated is a heterogeneous high-burnup (LEU,Th)O(2) fuelled bundle, whose two components (LEU in the outer 35 elements and thorium in the central eight elements) are analyzed separately. The LVRF central element was estimated to have a much lower toxicity than that of NU at all times after shutdown. Both the high burnup LEU and the thorium fuel had similar toxicity to NU at shutdown, but due to the creation of such inhalation hazards as (238)Pu, (240)Pu, (242)Am, (242)Cm, and (244)Cm (in high burnup LEU), and (232)U and (228)Th (in irradiated thorium), the toxicity of these fuels was almost double that of irradiated NU after 2,700 d of cooling. New urine bioassay methods for higher actinoids and the analysis of thorium in fecal samples are recommended to assess the internal dose from these two fuels.

Evaluation of the Biotoxicity of Tree Wood Ashes in Zebrafish Embryos.

PubMed

Consigli, Veronica; Guarienti, Michela; Bilo, Fabjola; Benassi, Laura; Depero, Laura E; Bontempi, Elza; Presta, Marco

2016-10-01

Ashes derived from biomass combustion and used as soil fertilizers can generate negative environmental and human health risks, related to leaching of heavy metals and other putative toxic elements. Tree wood ash composition may vary depending on geographical location and surrounding industrial processes. In this study, we evaluated the biotoxicity of lixiviated tree wood ash samples from trees of the Ash (Fraxinus), Cherry (Pronus), Hazel (Corylus), and Black locust (Robinia) genus collected in an industrialized region in Northern Italy. Elemental chemical analysis of the samples was performed by total reflection X-ray fluorescence technique and their biotoxicity was assessed in zebrafish (Danio rerio) embryos. Ashes from Ash, Cherry, and Hazel trees, but not Black locust trees, had a high concentration of heavy metals and other putative toxic elements. Accordingly, a dose-dependent increase in mortality rate and morphological and teratogenic defects was observed in zebrafish embryos treated with lixiviated Ash, Cherry, and Hazel tree wood samples, whereas the toxicity of Black locust tree wood ashes was negligible. In conclusion, lixiviated wood ashes from different plants show a different content of toxic elements that correlate with their biotoxic effects on zebrafish embryos. Tree wood ashes derived from biomass combustion may represent a potential risk for the environment and human health.

Microbial Diffraction Gratings as Optical Detectors for Heavy Metal Pollutants

NASA Technical Reports Server (NTRS)

Noever, David; Matsos, Helen; Brittain, Andrew; Obenhuber, Don; Cronise, Raymond; Armstrong, Shannon

1996-01-01

As a significant industrial pollutant, cadmium is implicated as the cause of itai-itai disease. For biological detection of cadmium toxicity, an assay device has been developed using the motile response of the protozoa species, Tetrahymena pyriformis. This mobile protozoa measures 50 microns in diameter, swims at 10 body lengths per second, and aggregates into macroscopically visible patterns at high organism concentrations. The assay demonstrates a Cd(+2) sensitivity better than 1 micro-M and a toxicity threshold to 5 micro-M, thus encouraging the study of these microbial cultures as viable pollution detectors. Using two-dimensional diffraction patterns within a Tetrahymena culture, the scattered light intensity varies with different organism densities (population counts). The resulting density profile correlates strongly with the toxic effects at very low dosages for cadmium (less than 5 ppm) and then for poison protection directly (with nickel and copper antagonists competing with cadmium absorption). In particular, copper dosages as low as 0.1-0.5 mM Cu have shown protective antagonism against cadmium, have enhanced density variability for cultures containing 1 mM Cd(+2) and therefore have demonstrated the sensitivity of the optical detection system. In this way, such microbial diffraction patterns give a responsive optical measure of biological culture changes and toxicity determination in aqueous samples of heavy metals and industrial pollutants.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Preez-Coll, C.S.; Herkovits, J.

Over the last several years, environmental contamination with cadmium has significantly increased because of its extensive use In anthropogenic activities. This heavy metal is a very toxic xenobiotic producing reproductive and developmental impairments in a wide spectrum of organisms. Within the life cycle of organisms, the embryo is the most sensitive period to adverse conditions. Moreover, stage-dependent susceptibilities to toxic agents in amphibian embryos treated with lead, cadmium and aluminium were described. In the case of cadmium, this differential sensitivity could be related to changes in the metal accumulation through development or in the induction of defense mechanisms against cadmiummore » toxicity, such as metallothionein (Mt) synthesis, which seems to be developmentally regulated. In the case of the toad Bufo arenarum, susceptibility to cadmium seems to follow a biphasic pattern during embryonic development. From the two-cell stage to the neurula stage an increase in susceptibility occurs, whereas from the last stage onwards a gradual increase in the resistance against this heavy metal seems to be achieved. This stage reports the uptake profile of cadmium at different post-hatching stages. 20 refs., 3 figs.« less

A pilot study in non-human primates shows no adverse response to intravenous injection of quantum dots.

PubMed

Ye, Ling; Yong, Ken-Tye; Liu, Liwei; Roy, Indrajit; Hu, Rui; Zhu, Jing; Cai, Hongxing; Law, Wing-Cheung; Liu, Jianwei; Wang, Kai; Liu, Jing; Liu, Yaqian; Hu, Yazhuo; Zhang, Xihe; Swihart, Mark T; Prasad, Paras N

2012-05-20

Quantum dots have been used in biomedical research for imaging, diagnostics and sensing purposes. However, concerns over the cytotoxicity of their heavy metal constituents and conflicting results from in vitro and small animal toxicity studies have limited their translation towards clinical applications. Here, we show in a pilot study that rhesus macaques injected with phospholipid micelle-encapsulated CdSe/CdS/ZnS quantum dots do not exhibit evidence of toxicity. Blood and biochemical markers remained within normal ranges following treatment, and histology of major organs after 90 days showed no abnormalities. Our results show that acute toxicity of these quantum dots in vivo can be minimal. However, chemical analysis revealed that most of the initial dose of cadmium remained in the liver, spleen and kidneys after 90 days. This means that the breakdown and clearance of quantum dots is quite slow, suggesting that longer-term studies will be required to determine the ultimate fate of these heavy metals and the impact of their persistence in primates.

In vivo effects of cadmium chloride on certain aspects of carbohydrate metabolism in the tissues of a freshwater field crab Barytelphusa guerini

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reddy, S.L.N.; Venugopal, N.B.R.K.; Ramana Rao, J.V.

1989-06-01

Cadmium is a toxic, non-essential heavy metal inhibiting numerous enzymes with functional sulfhydryl groups. Among the animals, aquatic organisms are most sensitive to heavy metals. Various aspects of toxic effects of cadmium pollution on fishes have been extensively reviewed. Survey of literature reveals that relatively few attempts have been made on the various aspects of cadmium toxicity in crustaceans and these studies were mainly devoted to marine forms. The freshwater crustaceans, particularly the freshwater field crab, Barytelphusa guerini, received less attention. This crab forms one of the major components of the paddy field ecosystem and has an edible importance amongmore » local populations. Apart from this, these crabs are easily available, maintainable in the laboratory and data obtained in this study can be extrapolated to other crustaceans. The present study reports the influence of cadmium on certain aspects of carbohydrate metabolism in the tissues of the freshwater field crab, Barytelphusa guerini, exposed to sublethal concentration of cadmium chloride.« less

Potential Biotechnological Strategies for the Cleanup of Heavy Metals and Metalloids

PubMed Central

Mosa, Kareem A.; Saadoun, Ismail; Kumar, Kundan; Helmy, Mohamed; Dhankher, Om Parkash

2016-01-01

Global mechanization, urbanization, and various natural processes have led to the increased release of toxic compounds into the biosphere. These hazardous toxic pollutants include a variety of organic and inorganic compounds, which pose a serious threat to the ecosystem. The contamination of soil and water are the major environmental concerns in the present scenario. This leads to a greater need for remediation of contaminated soils and water with suitable approaches and mechanisms. The conventional remediation of contaminated sites commonly involves the physical removal of contaminants, and their disposition. Physical remediation strategies are expensive, non-specific and often make the soil unsuitable for agriculture and other uses by disturbing the microenvironment. Owing to these concerns, there has been increased interest in eco-friendly and sustainable approaches such as bioremediation, phytoremediation and rhizoremediation for the cleanup of contaminated sites. This review lays particular emphasis on biotechnological approaches and strategies for heavy metal and metalloid containment removal from the environment, highlighting the advances and implications of bioremediation and phytoremediation as well as their utilization in cleaning-up toxic pollutants from contaminated environments. PMID:27014323

Migration and speciation of heavy metal in salinized mine tailings affected by iron mining.

PubMed

Zhang, Xu; Yang, Huanhuan; Cui, Zhaojie

2017-10-01

The negative effects of heavy metals have aroused much attention due to their high toxicity to human beings. Migration and transformation trend of heavy metals have a close relationship with soil safety. Researching on migration and transformation of heavy metals in tailings can provide a reliable basis for pollution management and ecosystem restoration. Heavy metal speciation plays an important role in risk assessment. We chose Anshan tailings for our study, including field investigations and laboratory research. Four typical heavy metal elements of mine tailings {Fe (373.89 g/kg), Mn (2,303.80 mg/kg), Pb (40.99 mg/kg) and Cr (199.92 mg/kg)} were studied via Tessier test in vertical and horizontal direction. The main speciation of heavy metals in Anshan tailings was the residual. However, heavy metals have a strong ability for migration and transformation in vertical and horizontal directions. Its tendency to change from stable to unstable speciation results in increasing bioavailability and potential bioavailability. Fe, Mn, Pb and Cr showed different ability in the migration and transformation process (Mn > Pb > Fe > Cr) depending on the characteristics of heavy metals and physicochemical properties of the environment.

Synergistic Effects of Heavy Metals and Pesticides in Living Systems.

PubMed

Singh, Nitika; Gupta, Vivek Kumar; Kumar, Abhishek; Sharma, Bechan

2017-01-01

There is a widespread repeated exposure of the population to the pesticides and heavy metals of occupational and environmental origin. Such population is forced to undergo continuous stress imposed by combined exposure of the heavy metals and different classes of the pesticides used in agricultural as well as health practices. The existing reports from several workers have indicated that heavy metals and pesticides in combination may lead more severe impact on the human health when compared to their individual effects. Such a combination of pesticides and heavy metals may also change or influence the detection of exposure. Several studies in past have shown the synergistic toxic effects of heavy metals and pesticides. Such evaluations have revealed the synergistic interactions of various heavy metals and pesticides in animals as well as humans. The aim of the present article is to provide a synthesis of existing knowledge on the synergistic effects of heavy metal and pesticides in living systems. The information included in this article may be useful for different environment protection agencies and policy makers to consider the combined effects of heavy metals and pesticides on humans while designing strategies toward environmental protection and safety regulations about human health.

Transfer of heavy metals through terrestrial food webs: a review.

PubMed

Gall, Jillian E; Boyd, Robert S; Rajakaruna, Nishanta

2015-04-01

Heavy metals are released into the environment by both anthropogenic and natural sources. Highly reactive and often toxic at low concentrations, they may enter soils and groundwater, bioaccumulate in food webs, and adversely affect biota. Heavy metals also may remain in the environment for years, posing long-term risks to life well after point sources of heavy metal pollution have been removed. In this review, we compile studies of the community-level effects of heavy metal pollution, including heavy metal transfer from soils to plants, microbes, invertebrates, and to both small and large mammals (including humans). Many factors contribute to heavy metal accumulation in animals including behavior, physiology, and diet. Biotic effects of heavy metals are often quite different for essential and non-essential heavy metals, and vary depending on the specific metal involved. They also differ for adapted organisms, including metallophyte plants and heavy metal-tolerant insects, which occur in naturally high-metal habitats (such as serpentine soils) and have adaptations that allow them to tolerate exposure to relatively high concentrations of some heavy metals. Some metallophyte plants are hyperaccumulators of certain heavy metals and new technologies using them to clean metal-contaminated soil (phytoextraction) may offer economically attractive solutions to some metal pollution challenges. These new technologies provide incentive to catalog and protect the unique biodiversity of habitats that have naturally high levels of heavy metals.

Exposure, metabolism, and toxicity of rare earths and related compounds.

PubMed

Hirano, S; Suzuki, K T

1996-03-01

For the past three decades, most attention in heavy metal toxicology has been paid to cadmium, mercury, lead, chromium, nickel, vanadium, and tin because these metals widely polluted the environment. However, with the development of new materials in the last decade, the need for toxicological studies on those new materials has been increasing. A group of rare earths (RE) is a good example. Although some RE have been used for superconductors, plastic magnets, and ceramics, few toxicological data are available compared to other heavy metals described above. Because chemical properties of RE are very similar, it is plausible that their binding affinities to biomolecules, metabolism, and toxicity in the living system are also very similar. In this report, we present an overview of the metabolism and health hazards of RE and related compounds, including our recent studies.

Approaches for enhanced phytoextraction of heavy metals.

PubMed

Bhargava, Atul; Carmona, Francisco F; Bhargava, Meenakshi; Srivastava, Shilpi

2012-08-30

The contamination of the environment with toxic metals has become a worldwide problem. Metal toxicity affects crop yields, soil biomass and fertility. Soils polluted with heavy metals pose a serious health hazard to humans as well as plants and animals, and often requires soil remediation practices. Phytoextraction refers to the uptake of contaminants from soil or water by plant roots and their translocation to any harvestable plant part. Phytoextraction has the potential to remove contaminants and promote long-term cleanup of soil or wastewater. The success of phytoextraction as a potential environmental cleanup technology depends on factors like metal availability for uptake, as well as plants ability to absorb and accumulate metals in aerial parts. Efforts are ongoing to understand the genetics and biochemistry of metal uptake, transport and storage in hyperaccumulator plants so as to be able to develop transgenic plants with improved phytoremediation capability. Many plant species are being investigated to determine their usefulness for phytoextraction, especially high biomass crops. The present review aims to give an updated version of information available with respect to metal tolerance and accumulation mechanisms in plants, as well as on the environmental and genetic factors affecting heavy metal uptake. The genetic tools of classical breeding and genetic engineering have opened the door to creation of 'remediation' cultivars. An overview is presented on the possible strategies for developing novel genotypes with increased metal accumulation and tolerance to toxicity. Copyright © 2012 Elsevier Ltd. All rights reserved.

Nanoparticles: their potential toxicity, waste and environmental management.

PubMed

Bystrzejewska-Piotrowska, Grazyna; Golimowski, Jerzy; Urban, Pawel L

2009-09-01

This literature review discusses specific issues related to handling of waste containing nanomaterials. The aims are (1) to highlight problems related to uncontrolled release of nanoparticles to the environment through waste disposal, and (2) to introduce the topics of nanowaste and nanotoxicology to the waste management community. Many nanoparticles used by industry contain heavy metals, thus toxicity and bioaccumulation of heavy metals contained in nanoparticles may become important environmental issues. Although bioavailability of heavy metals contained in nanoparticles can be lower than those present in soluble form, the toxicity resulting from their intrinsic nature (e.g. their size, shape or density) may be significant. An approach to the treatment of nanowaste requires understanding of all its properties--not only chemical, but also physical and biological. Progress in nanowaste management also requires studies of the environmental impact of the new materials. The authors believe Amara's law is applicable to the impact of nanotechnologies, and society might overestimate the short-term effects of these technologies, while underestimating the long-term effects. It is necessary to have basic information from companies about the level and nature of nanomaterials produced or emitted and about the expectation of the life cycle time of nanoproducts as a basis to estimate the level of nanowaste in the future. Without knowing how companies plan to use and store recycled and nonrecycled nanomaterials, development of regulations is difficult. Tagging of nanoproducts is proposed as a means to facilitate separation and recovery of nanomaterials.

Toxicity potentials from waste cellular phones, and a waste management policy integrating consumer, corporate, and government responsibilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, Seong-Rin; Schoenung, Julie M., E-mail: jmschoenung@ucdavis.ed

Cellular phones have high environmental impact potentials because of their heavy metal content and current consumer attitudes toward purchasing new phones with higher functionality and neglecting to return waste phones into proper take-back systems. This study evaluates human health and ecological toxicity potentials from waste cellular phones; highlights consumer, corporate, and government responsibilities for effective waste management; and identifies key elements needed for an effective waste management strategy. The toxicity potentials are evaluated by using heavy metal content, respective characterization factors, and a pathway and impact model for heavy metals that considers end-of-life disposal in landfills or by incineration. Cancermore » potentials derive primarily from Pb and As; non-cancer potentials primarily from Cu and Pb; and ecotoxicity potentials primarily from Cu and Hg. These results are not completely in agreement with previous work in which leachability thresholds were the metric used to establish priority, thereby indicating the need for multiple or revised metrics. The triple bottom line of consumer, corporate, and government responsibilities is emphasized in terms of consumer attitudes, design for environment (DfE), and establishment and implementation of waste management systems including recycling streams, respectively. The key strategic elements for effective waste management include environmental taxation and a deposit-refund system to motivate consumer responsibility, which is linked and integrated with corporate and government responsibilities. The results of this study can contribute to DfE and waste management policy for cellular phones.« less

Toxicity potentials from waste cellular phones, and a waste management policy integrating consumer, corporate, and government responsibilities.

PubMed

Lim, Seong-Rin; Schoenung, Julie M

2010-01-01

Cellular phones have high environmental impact potentials because of their heavy metal content and current consumer attitudes toward purchasing new phones with higher functionality and neglecting to return waste phones into proper take-back systems. This study evaluates human health and ecological toxicity potentials from waste cellular phones; highlights consumer, corporate, and government responsibilities for effective waste management; and identifies key elements needed for an effective waste management strategy. The toxicity potentials are evaluated by using heavy metal content, respective characterization factors, and a pathway and impact model for heavy metals that considers end-of-life disposal in landfills or by incineration. Cancer potentials derive primarily from Pb and As; non-cancer potentials primarily from Cu and Pb; and ecotoxicity potentials primarily from Cu and Hg. These results are not completely in agreement with previous work in which leachability thresholds were the metric used to establish priority, thereby indicating the need for multiple or revised metrics. The triple bottom line of consumer, corporate, and government responsibilities is emphasized in terms of consumer attitudes, design for environment (DfE), and establishment and implementation of waste management systems including recycling streams, respectively. The key strategic elements for effective waste management include environmental taxation and a deposit-refund system to motivate consumer responsibility, which is linked and integrated with corporate and government responsibilities. The results of this study can contribute to DfE and waste management policy for cellular phones. 2010 Elsevier Ltd. All rights reserved.

Heavy-metal pollution and potential ecological risk assessment of sediments from Baihua Lake, Guizhou, P.R. China.

PubMed

Huang, Xianfei; Hu, Jiwei; Li, Cunxiong; Deng, Jiajun; Long, Jian; Qin, Fanxin

2009-12-01

Baihua Lake, a man-made reservoir, is one of the five drinking water sources for Guiyang City in China's southwestern province of Guizhou. In the present research, the distribution and accumulation characteristics of heavy metals (Pb, Cd, As, Cu and Zn) for the sediment of this lake were analyzed by examination of 10 recently collected samples. A method based on toxic-response factor was applied to assess the potential ecological risk of these heavy metals to the water body. For comparison, the two sets of reference data representing the pre-industrial and the local baseline pollution levels were employed to derive the accumulating coefficients for the heavy metals under study. The calculated potential ecological risk indices show that the lake was polluted by heavy metals and both cadmium and arsenic loadings were critical factors responsible for the ecological hazards posed to Baihua Lake by the five elements.

Cytoplasmic inorganic polyphosphate participates in the heavy metal tolerance of Cryptococcus humicola.

PubMed

Andreeva, Nadezhda; Ryazanova, Lubov; Dmitriev, Vladimir; Kulakovskaya, Tatiana; Kulaev, Igor

2014-09-01

The basidiomycetous yeast Cryptococcus humicola was shown to be tolerant to manganese, cobalt, nickel, zinc, lanthanum, and cadmium cations at a concentration of 2.5 mmol/L, which is toxic for many yeasts. The basidiomycetous yeast Cryptococcus terreus was sensitive to all these ions and did not grow at the above concentration. In the presence of heavy metal cations, С. humicola, as opposed to C. terreus, was characterized by the higher content of acid-soluble inorganic polyphosphates. In vivo 4',6'-diamino-2-phenylindole dihydrochloride staining revealed polyphosphate accumulation in the cell wall and cytoplasmic inclusions of С. humicola in the presence of heavy metals. In C. terreus, polyphosphates in the presence of heavy metals accumulate mainly in vacuoles, which results in morphological changes in these organelles and, probably, disturbance of their function. The role of polyphosphate accumulation and cellular localization as factors of heavy metal tolerance of Cryptococcus humicola is discussed.

Impact of toxic chemicals on local wastewater treatment plant and the environment

NASA Astrophysics Data System (ADS)

Bennett, Gary F.

1989-05-01

Because toxic chemicals being discharged to sewers were simultaneously interfering with wastewater treatment processes of municipal, biological treatment plants and were passing through these plants to negatively impact the bodies of water to which these plants were discharging, the U.S. Environmental Protection Agency issued regulations governing industrial discharges to municipal sewers. These “Pretreatment Regulations” limit industrial discharges to municipal sewers of heavy metals, oil and grease, acids and bases, and toxic organic chemicals. This paper discusses the evolution of these regulations, the basis for them, the types of regulations (categorical and local), and the rationale for their promulgation based on the impacts of toxics chemicals on the treatment plant and receiving system. Finally, the expected results of these regulations in reducing industrial discharges of toxic chemicals is discussed.

Biological approaches to tackle heavy metal pollution: A survey of literature.

PubMed

Jacob, Jaya Mary; Karthik, Chinnannan; Saratale, Rijuta Ganesh; Kumar, Smita S; Prabakar, Desika; Kadirvelu, K; Pugazhendhi, Arivalagan

2018-07-01

Pollution by heavy metals has been identified as a global threat since the inception of industrial revolution. Heavy metal contamination induces serious health and environmental hazards due to its toxic nature. Remediation of heavy metals by conventional methods is uneconomical and generates a large quantity of secondary wastes. On the other hand, biological agents such as plants, microorganisms etc. offer easy and eco-friendly ways for metal removal; hence, considered as efficient and alternative tools for metal removal. Bioremediation involves adsorption, reduction or removal of contaminants from the environment through biological resources (both microorganisms and plants). The heavy metal remediation properties of microorganisms stem from their self defense mechanisms such as enzyme secretion, cellular morphological changes etc. These defence mechanisms comprise the active involvement of microbial enzymes such as oxidoreductases, oxygenases etc, which influence the rates of bioremediation. Further, immobilization techniques are improving the practice at industrial scales. This article summarizes the various strategies inherent in the biological sorption and remediation of heavy metals. Copyright © 2018 Elsevier Ltd. All rights reserved.

Pollution Status of Pakistan: A Retrospective Review on Heavy Metal Contamination of Water, Soil, and Vegetables

PubMed Central

Arshad, Jahanzaib; Iqbal, Farhat; Sajjad, Ashif; Mehmood, Zahid

2014-01-01

Trace heavy metals, such as arsenic, cadmium, lead, chromium, nickel, and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. In addition to these metals, copper, manganese, iron, and zinc are also important trace micronutrients. The presence of trace heavy metals in the atmosphere, soil, and water can cause serious problems to all organisms, and the ubiquitous bioavailability of these heavy metal can result in bioaccumulation in the food chain which especially can be highly dangerous to human health. This study reviews the heavy metal contamination in several areas of Pakistan over the past few years, particularly to assess the heavy metal contamination in water (ground water, surface water, and waste water), soil, sediments, particulate matter, and vegetables. The listed contaminations affect the drinking water quality, ecological environment, and food chain. Moreover, the toxicity induced by contaminated water, soil, and vegetables poses serious threat to human health. PMID:25276818

An artificial tongue fluorescent sensor array for identification and quantitation of various heavy metal ions.

PubMed

Xu, Wang; Ren, Changliang; Teoh, Chai Lean; Peng, Juanjuan; Gadre, Shubhankar Haribhau; Rhee, Hyun-Woo; Lee, Chi-Lik Ken; Chang, Young-Tae

2014-09-02

Herein, a small-molecule fluorescent sensor array for rapid identification of seven heavy metal ions was designed and synthesized, with its sensing mechanism mimicking that of a tongue. The photoinduced electron transfer and intramolecular charge transfer mechanism result in combinatorial interactions between sensor array and heavy metal ions, which lead to diversified fluorescence wavelength shifts and emission intensity changes. Upon principle component analysis (PCA), this result renders clear identification of each heavy metal ion on a 3D spatial dispersion graph. Further exploration provides a concentration-dependent pattern, allowing both qualitative and quantitative measurements of heavy metal ions. On the basis of this information, a "safe-zone" concept was proposed, which provides rapid exclusion of versatile hazardous species from clean water samples based on toxicity characteristic leaching procedure standards. This type of small-molecule fluorescent sensor array could open a new avenue for multiple heavy metal ion detection and simplified water quality analysis.

Recovery of Trace and Heavy Metals from Coal Combustion Residues for Reuse and Safe Disposal: A Review

NASA Astrophysics Data System (ADS)

Kumar, Ashvani; Samadder, Sukha Ranjan; Elumalai, Suresh Pandian

2016-09-01

The safe disposal of coal combustion residues (CCRs) will remain a major public issue as long as coal is used as a fuel for energy production. Both dry and wet disposal methods of CCRs create serious environmental problems. The dry disposal method creates air pollution initially, and the wet disposal method creates water pollution as a result of the presence of trace and heavy metals. These leached heavy metals from fly ash may become more hazardous when they form toxic compounds such as arsenic sulfite (As2S3) and lead nitrate (N2O6Pb). The available studies on trace and heavy metals present in CCRs cannot ensure environmentally safe utilization. In this work, a novel approach has been offered for the retrieval of trace and heavy metals from CCRs. If the proposed method becomes successful, then the recovered trace and heavy metals may become a resource and environmentally safe use of CCRs may be possible.

Determination of toxic metals, trace and essentials, and macronutrients in Sarpa salpa and Chelon labrosus: risk assessment for the consumers.

PubMed

Afonso, Aridani; Gutiérrez, Angel J; Lozano, Gonzalo; González-Weller, Dailos; Rubio, Carmen; Caballero, José M; Hardisson, Arturo; Revert, Consuelo

2017-04-01

Due to increased environmental pollution, monitoring of contaminants in the environment and marine organisms is a fundamental tool for assessing the existence of risk from their consumption to human health. The levels of toxic heavy metals (Cd, Pb, and Al), trace and essential metals (B, Ba, Co, Cu, Cr, Fe, Li, Mn, Mo, Ni, Sr, V, and Zn), and macronutrients (Ca, K, Mg, Na) in two species of fish for human consumption were quantified in the present study. Eighty samples of muscle tissue and 80 samples of liver tissue belonging to two species of Osteichthyes fish; Sarpa salpa and Chelon labrosus were analyzed. The studied specimens were caught on the northern coast of Gran Canaria (Canary Islands) with fishing rods. As they caught from the shore, they are suitable samples for assessing the toxic levels of representative species caught by local amateur fishermen. The results show that both species are fit for human consumption since they have toxic levels of heavy metals (Cd, Pb, and Al) which are below the maximum established levels; however, the toxic levels of the liver samples are several orders of magnitude higher than the muscle samples, so we discourage their regular consumption. The risk assessment indicated that the two species of fish are safe for the average consumer; however, if the livers of these species are consumed, there could be risks because they exceed the PTWI for Pb and the TWI for Cd.

Isolation of lead-resistant Arthrobactor strain GQ-9 and its biosorption mechanism.

PubMed

Wang, Tianqi; Yao, Jun; Yuan, Zhimin; Zhao, Yue; Wang, Fei; Chen, Huilun

2018-02-01

In this study, lead-resistant bacterium Arthrobacter sp. GQ-9 with a resistant capability to cadmium, zinc, and copper was isolated from a heavy metal polluted soil. Microcalorimetry analysis was applied to assess the strain's microbial activity under Pb(II) stress and suggested that GQ-9's microbial activities under Pb(II) stress were stronger than a non-resistant strain. Biosorption batch experiments revealed that the optimal condition for adsorption of Pb(II) by GQ-9 was pH 5.5, a biomass dosage of 1.2 g L -1 , and an initial Pb(II) concentration of 100 mg L -1 with a maximum biosorption capacity of 17.56 mg g -1 .Adsorption-desorption experiments and Fourier transform infrared spectroscopy (FTIR) analysis were applied to elucidate the biosorption mechanisms. Adsorption-desorption analysis showed that GQ-9 cells could sequester 56.60% of the adsorbed Pb(II) ions on the cell wall. FTIR analysis suggested that hydroxyl, carboxyl, amino, nitrile, and sulfhydryl groups and amide I, amide II bands on the GQ-9 cell wall participated in the complexation of Pb(II) ions. The present study illustrates that the lead-resistant bacteria GQ-9 has the potential for further development of an effective and ecofriendly adsorbent for heavy metal bioremediation.

A preliminary survey of marine contamination from mining-related activities on Marinduque Island, Philippines: porewater toxicity and chemistry results from a field trip, October 14-19, 2000

USGS Publications Warehouse

Carr, R. Scott; Nipper, Marion; Plumlee, Geoffrey S.

2001-01-01

As a follow-up of an initial overview of environmental problems caused by mining activities on Marinduque Island, Philippines, USGS and TAMU-CC scientists went to Marinduque in October 2000 to do a preliminary assessment of potential impacts of mining-related activities on the marine environment. Like the previous visit in May 2000, the marine assessment was conducted at the invitation of Philippine Congressman Edmund O. Reyes. In this report we present the results of sediment porewater toxicity tests and chemical analyses. Toxicity tests consist of laboratory analyses for the assessment of adverse effects caused by environmental contaminants to animals or plants. Sediments (sand or mud) are known to accumulate contaminants (e.g., copper and other heavy metals). Therefore, it is common to perform toxicity tests using different phases of the sedimentary environment in order to analyze adverse effects of contaminants accumulated in the sediment. Sediment pore water (or interstitial water, i.e., the water distributed among the sediment grains) is a sedimentary phase which controls the bioavailability of contaminants to bottom dwelling aquatic organisms (both plants and animals). There are several different kinds of organisms with which toxicity tests can be performed. Among those, tests with sea urchin early life stages (gametes and embryos) are very common due to their high sensitivity to contaminants, ease of maintenance under laboratory conditions, and ecological importance, particularly in coral reefs. The basis of these tests is the exposure of gametes or embryos to the pore water to be analyzed for toxicity. If the pore water contains contaminants in levels that can adversely affect a number of marine species, fertilization and/or embryological development of sea urchins is inhibited. Chemical analyses provide additional information and aid in the interpretation of the toxicity test results. For the current study, chemical analyses were performed for the measurement of porewater concentrations of several heavy metals associated with copper mining activities. Pore waters for toxicological and chemical analyses were collected at several stations on the coast of Marinduque, near the mouths of the Boac and Mogpog rivers, and near the causeways formed by mine tailings disposal. Porewater samples were also collected at the Tres Reyes Marine Reserve, so that these non-contaminated samples could serve as a reference for test performance. Sea urchin embryological development and fertilization were only significantly impaired by two porewater samples, suggesting the presence of contaminants in toxic amounts at those stations. The toxic samples were collected near the up current side of the Calancan (Marcopper) mine tailings causeway (stations 2 and 3 – see figure 10). The pore water from station 2 also had the highest levels of heavy metals, particularly cadmium, cobalt, copper, nickel, lead and zinc (Table 5). The concentrations of cobalt, nickel and zinc were also elevated 2 at station 3. Copper concentrations were also elevated at the two river mouth stations (8 and 9) and near the CMI tailings causeway (station 7). Visual observations also indicated biological degradation due to heavy siltation and smothered coral at a gradient off the Calancan causeway, suggesting that siltation might also be causing a physical impact. This preliminary survey suggests that effects related to past mining activities are still evident and warrant a more comprehensive study to assess their severity and areal extent.

Effect of Heavy Metals in Plants of the Genus Brassica

PubMed Central

Mourato, Miguel P.; Moreira, Inês N.; Leitão, Inês; Pinto, Filipa R.; Sales, Joana R.; Louro Martins, Luisa

2015-01-01

Several species from the Brassica genus are very important agricultural crops in different parts of the world and are also known to be heavy metal accumulators. There have been a large number of studies regarding the tolerance, uptake and defense mechanism in several of these species, notably Brassica juncea and B. napus, against the stress induced by heavy metals. Numerous studies have also been published about the capacity of these species to be used for phytoremediation purposes but with mixed results. This review will focus on the latest developments in the study of the uptake capacity, oxidative damage and biochemical and physiological tolerance and defense mechanisms to heavy metal toxicity on six economically important species: B. juncea, B. napus, B. oleracea, B. carinata, B. rapa and B. nigra. PMID:26247945

Pyrosequencing analysis of bacterial diversity in soils contaminated long-term with PAHs and heavy metals: Implications to bioremediation.

PubMed

Kuppusamy, Saranya; Thavamani, Palanisami; Megharaj, Mallavarapu; Venkateswarlu, Kadiyala; Lee, Yong Bok; Naidu, Ravi

2016-11-05

Diversity, distribution and composition of bacterial community of soils contaminated long-term with both polycyclic aromatic hydrocarbons (PAHs) and heavy metals were explored for the first time following 454 pyrosequencing. Strikingly, the complete picture of the Gram positive (+ve) and Gram negative (-ve) bacterial profile obtained in our study illustrates novel postulates that include: (1) Metal-tolerant and PAH-degrading Gram -ves belonging to the class Alphaproteobacteria persist relatively more in the real contaminated sites compared to Gram +ves, (2) Gram +ves are not always resistant to heavy metal toxicity, (3) Stenotrophomonas followed by Burkholderia and Pseudomonas are the dominant genera of PAH degraders with high metabolic activity in long-term contaminated soils, (4) Actinobacteria is the predominant group among the Gram +ves in soils contaminated with high molecular weight PAHs that co-exist with toxic heavy metals like Pb, Cu and Zn, (5) Microbial communities are nutrient-driven in natural environments and (6) Catabolically potential Gram +/-ves with diverse applicability to remediate the real contaminated sites evolve eventually in the historically-polluted soils. Thus, the most promising indigenous Gram +/-ve strains from the long-term contaminated sites with increased catabolic potential, enzymatic activity and metal tolerance need to be harnessed for mixed contaminant cleanups. Copyright © 2016 Elsevier B.V. All rights reserved.

Speciation and distribution characteristics of heavy metals and pollution assessments in the sediments of Nashina Lake, Heilongjiang, China.

PubMed

Li, Miao; Zang, Shuying; Xiao, Haifeng; Wu, Changshan

2014-05-01

Sediment core samples from Nashina Lake, Heilongjiang, China were collected using a gravity sampler. The cores were sliced horizontally at 1 cm each to determine the particle size, total concentrations and speciation of Cd, Cr, Cu, Mn, Ni, Pb, and Zn. Total concentrations of heavy metals were extracted using an acid mixture (containing hydro fluoric acid, nitric acid, and sulphuric acid) and analyzed using an inductively coupled plasma spectrometry. A sequential extraction procedure was employed to separate chemical species. Analysis of results indicate that the concentrations of heavy metals in the sediments of Nashina Lake in descending order are Mn, Cr, Zn, Pb, Ni, Cu, and Cd. The ratios of the average concentrations of four heavy metals (e.g.Cr, Cu, Ni, Zn) to their background values were >1; and those of Mn, Cd, and Pb were >1. Moreover, some toxic metals were mainly distributed in bioavailable fractions. For instance, both Cd and Mn were typically found in Acid-extractable species or Fe-Mn oxide species, and thus can be easily remobilized and enter the food chain. Finally, the analysis of geo-accumulation index showed that anthropogenic pollution levels of Cr, Cu, Mn, Ni, Zn were low, but those of Pb and Cd were at the moderate level. As both Pb and Cd are toxic metals, it is highly necessary to prohibit their transformation and accumulation in the sediments.

The effect of low-temperature transformation of mixtures of sewage sludge and plant materials on content, leachability and toxicity of heavy metals.

PubMed

Gondek, Krzysztof; Baran, Agnieszka; Kopeć, Michał

2014-12-01

The aim of the study was to determine the influence of the process of low-temperature transformation and the addition of plant material to sewage sludge diversifying the content of mobile forms of heavy metals and their ecotoxicity. The experimental design included: sewage sludge+rape straw, sewage sludge+wheat straw, sewage sludge+sawdust, sewage sludge+bark and sewage sludge with no addition. The mixtures were subjected to thermal transformation in a chamber furnace, under conditions without air. The procedure consisted of two stages: the first stage (130°C for 40 min) focused on drying the material, whereas in the second stage (200°C for 30 min) proper thermal transformation of materials took place. Thermal transformation of the materials, caused an increase in total contents of heavy metals in comparison to the material before transformation. From among elements, the cadmium content changed the most in materials after thermal transformation. As a result of thermal transformation, the content of water soluble form of the heavy metals decreased significantly in all the prepared mixtures. Low toxicity of the extracts from materials for Vibrio fischeri and Lepidium sativum was found in the research, regardless of transformation process. L. sativum showed higher sensitivity to heavy metals occurring in the studied extracts from materials than V. fischeri, evidence of which are the positive significant correlations between the content of metals and the inhibition of root growth of L. sativum. Copyright © 2014 Elsevier Ltd. All rights reserved.

Small Molecule Recognition and Tools to Study Modulation of r(CGG)(exp) in Fragile X-Associated Tremor Ataxia Syndrome.

PubMed

Yang, Wang-Yong; He, Fang; Strack, Rita L; Oh, Seok Yoon; Frazer, Michelle; Jaffrey, Samie R; Todd, Peter K; Disney, Matthew D

2016-09-16

RNA transcripts containing expanded nucleotide repeats cause many incurable diseases via various mechanisms. One such disorder, fragile X-associated tremor ataxia syndrome (FXTAS), is caused by a noncoding r(CGG) repeat expansion (r(CGG)(exp)) that (i) sequesters proteins involved in RNA metabolism in nuclear foci, causing dysregulation of alternative pre-mRNA splicing, and (ii) undergoes repeat associated non-ATG translation (RANT), which produces toxic homopolymeric proteins without using a start codon. Here, we describe the design of two small molecules that inhibit both modes of toxicity and the implementation of various tools to study perturbation of these cellular events. Competitive Chemical Cross Linking and Isolation by Pull Down (C-Chem-CLIP) established that compounds bind r(CGG)(exp) and defined small molecule occupancy of r(CGG)(exp) in cells, the first approach to do so. Using an RNA GFP mimic, r(CGG)(exp)-Spinach2, we observe that our optimal designed compound binds r(CGG)(exp) and affects RNA localization by disrupting preformed RNA foci. These events correlate with an improvement of pre-mRNA splicing defects caused by RNA gain of function. In addition, the compounds reduced levels of toxic homopolymeric proteins formed via RANT. Polysome profiling studies showed that small molecules decreased loading of polysomes onto r(CGG)(exp), explaining decreased translation.

Exploring the erodibility of sediments and harmful algal blooms in the Gulf of Maine

USGS Publications Warehouse

Butman, Bradford; Dickhudt, Patrick J.; Keafer, Bruce A.

2012-01-01

Investigators at the U.S. Geological Survey (USGS) are cooperating with scientists at Woods Hole Oceanographic Institution (WHOI) to investigate harmful algal blooms along the New England coast in the Gulf of Maine. These blooms are caused by cysts of the dinoflagellate Alexandrium fundyense that overwinter in the bottom sediments and germinate in spring. Depending on conditions such as temperature, light, nutrient levels, and currents, these single-celled organismscan create a bloom along the coast, called ‘red tides.’Shellfish that have ingested these cells in sufficient concentration can become toxic to humans and require that the shellfisheries be closed. After the spring bloom, the organisms form cysts that sink to the sea floor and are sequestered in the bottom sediments over the winter.

Heavy metal contamination of agricultural soils affected by mining activities around the Ganxi River in Chenzhou, Southern China.

PubMed

Ma, Li; Sun, Jing; Yang, Zhaoguang; Wang, Lin

2015-12-01

Heavy metal contamination attracted a wide spread attention due to their strong toxicity and persistence. The Ganxi River, located in Chenzhou City, Southern China, has been severely polluted by lead/zinc ore mining activities. This work investigated the heavy metal pollution in agricultural soils around the Ganxi River. The total concentrations of heavy metals were determined by inductively coupled plasma-mass spectrometry. The potential risk associated with the heavy metals in soil was assessed by Nemerow comprehensive index and potential ecological risk index. In both methods, the study area was rated as very high risk. Multivariate statistical methods including Pearson's correlation analysis, hierarchical cluster analysis, and principal component analysis were employed to evaluate the relationships between heavy metals, as well as the correlation between heavy metals and pH, to identify the metal sources. Three distinct clusters have been observed by hierarchical cluster analysis. In principal component analysis, a total of two components were extracted to explain over 90% of the total variance, both of which were associated with anthropogenic sources.

A review on various electrochemical techniques for heavy metal ions detection with different sensing platforms.

PubMed

Bansod, BabanKumar; Kumar, Tejinder; Thakur, Ritula; Rana, Shakshi; Singh, Inderbir

2017-08-15

Heavy metal ions are non-biodegradable and contaminate most of the natural resources occurring in the environment including water. Some of the heavy metals including Lead (Pb), Mercury (Hg), Arsenic (As), Chromium (Cr) and Cadmium (Cd) are considered to be highly toxic and hazardous to human health even at trace levels. This leads to the requirement of fast, accurate and reliable techniques for the detection of heavy metal ions. This review presents various electrochemical detection techniques for heavy metal ions those are user friendly, low cost, provides on-site and real time monitoring as compared to other spectroscopic and optical techniques. The categorization of different electrochemical techniques is done on the basis of different types of detection signals generated due to presence of heavy metal ions in the solution matrix like current, potential, conductivity, electrochemical impedance, and electrochemiluminescence. Also, the recent trends in electrochemical detection of heavy metal ions with various types of sensing platforms including metals, metal films, metal oxides, nanomaterials, carbon nano tubes, polymers, microspheres and biomaterials have been evoked. Copyright © 2017 Elsevier B.V. All rights reserved.

Heavy Metal Displacement in Chelate-Assisted Phytoremediation of Biosolids Soil

NASA Astrophysics Data System (ADS)

Kirkham, M. B.; Liphadzi, M. S.

2005-05-01

Heavy metals in biosolids (sewage sludge) applied to land contaminate the soil. Phytoremediation, the use of plants to clean up toxic heavy metals, might remove them. Chelating agents are added to soil to solubilize the metals for enhanced phytoextraction. Yet no studies follow the displacement and leaching of heavy metals in soil with biosolids following solubilization with chelates. The objective of this work was to determine the mobility of heavy metals, as affected by a chelate, in soil (Haynie very fine sandy loam) from a 25-year old sludge farm. Soil columns (105 cm long; 39 cm in diameter) either had a plant (hybrid poplar; Populus deltoides Marsh. x P. nigra L.) or no plant. When the poplars were 144 days old, the tetrasodium salt of the chelating agent EDTA (ethylenediamine-tetraacetic acid) was irrigated onto the soil at a rate of 1 g per kg of soil. Drainage water, soil, and plants were analyzed for three toxic heavy metals (Cd, Ni, Pb) and four essential heavy metals (Cu, Fe, Mn, Zn). Without EDTA, concentrations of the seven heavy metals in the leachate from columns with or without plants were low or below detection limits. With or without plants, the EDTA mobilized all heavy metals and increased their concentration in drainage water. Without plants, the concentrations of Cd, Cu, Fe, Pb, and Zn in the leachate from columns with EDTA were above drinking-water standards. (There is no drinking-water standard for Ni.) The presence of poplar plants in the soil reduced the concentrations of Cu, Fe, and Zn in the leachate so it fell within drinking-water standards. Concentrations of Cd and Pb in the leachate remained above drinking-water standards with or without plants. At harvest (124 days after the EDTA application), total concentration of each heavy metal in the soil at different depths in the columns with EDTA was similar to that in the columns without EDTA. The chelate did not affect the concentration of heavy metals in the roots, stems, or leaves. However, the wood, which contains the xylem, from plants grown with EDTA had a higher concentration of Ni and Pb than did wood from plants grown with no EDTA. The results showed that heavy metals in soil with sludge treated with EDTA could contaminate ground water, even in the presence of plant roots. (This research is part of the dissertation of M.S. Liphadzi, who was supported by a Fulbright Fellowship.)

Indicators: Soil Chemistry

EPA Pesticide Factsheets

The chemical makeup of the soil can provide information on wetland condition, wetland water quality and services being provided by the wetland ecosystem. Analyzing soil chemistry reveals if the soil is contaminated with a toxic chemical or heavy metal.

41 CFR 101-42.1102-7 - Lead-containing paint and items bearing lead-containing paint.

Code of Federal Regulations, 2012 CFR

2012-07-01

... toxic heavy metal which, in humans, exerts its effects on the renal, hematopoietic, and nervous systems... Property Management Federal Property Management Regulations System FEDERAL PROPERTY MANAGEMENT REGULATIONS...

41 CFR 101-42.1102-7 - Lead-containing paint and items bearing lead-containing paint.

Code of Federal Regulations, 2014 CFR

2014-07-01

... toxic heavy metal which, in humans, exerts its effects on the renal, hematopoietic, and nervous systems... Management Federal Property Management Regulations System FEDERAL PROPERTY MANAGEMENT REGULATIONS UTILIZATION...

41 CFR 101-42.1102-7 - Lead-containing paint and items bearing lead-containing paint.

Code of Federal Regulations, 2013 CFR

2013-07-01

... toxic heavy metal which, in humans, exerts its effects on the renal, hematopoietic, and nervous systems... Management Federal Property Management Regulations System FEDERAL PROPERTY MANAGEMENT REGULATIONS UTILIZATION...

41 CFR 101-42.1102-7 - Lead-containing paint and items bearing lead-containing paint.

Code of Federal Regulations, 2010 CFR

2010-07-01

... toxic heavy metal which, in humans, exerts its effects on the renal, hematopoietic, and nervous systems... Management Federal Property Management Regulations System FEDERAL PROPERTY MANAGEMENT REGULATIONS UTILIZATION...

41 CFR 101-42.1102-7 - Lead-containing paint and items bearing lead-containing paint.

Code of Federal Regulations, 2011 CFR

2011-07-01

... toxic heavy metal which, in humans, exerts its effects on the renal, hematopoietic, and nervous systems... Management Federal Property Management Regulations System FEDERAL PROPERTY MANAGEMENT REGULATIONS UTILIZATION...

Emerging Contaminants.

EPA Science Inventory

Recent temporal trends of contaminants from Narragansett Bay show the appearance of CECs resulting from the use of personal care products, pharmaceuticals and industrial products over time. In contrast, legacy contaminants such as PCBs and toxic heavy metals generally show susta...

Anti-Ig autoantibody and complement-mediated destruction of neoplastic cells

NASA Technical Reports Server (NTRS)

Towmey, J. J.

1976-01-01

Some immune response are effected through immunoglobulins (Ig), of which five classes have been recognized, namely, IgA, IgD, IgE, IgG, and IgM. Auto-antibodies associated with rheumatoid arthritis, termed rheumatoid factors (RF) react with antigenic determinants on IgG heavy chains. RF has predominant but not complete IgM specificity. This auto-antibody response was not detected in treated patients with primary brain tumors (where tissue is sequestered from the immune system by an intact bloodbrain barrier) or with multiple myeloma where humoral immunity is usually impaired. In addition, the prevalence of RF is not increased with solid tumors prior to initiation of chemotherapy or radiotherapy. It is proposed that RF is related to prior chemotherapy or radiotherapy of tumors anatomically accessible to immunologic tissues capable of antibody responses. A primary IgG response occurs, antigen-antibody complexes form, complexed IgG becomes immunologic, and an RF response results.

Selenium-tolerant diamondback moth disarms hyperaccumulator plantdefense

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freeman, J.L.; Quinn, C.F.; Marcus, M.A.

2006-11-20

Background Some plants hyperaccumulate the toxic element selenium (Se) to extreme levels, up to 1% of dry weight. The function of this intriguing phenomenon is obscure. Results Here, we show that the Se in the hyperaccumulator prince's plume (Stanleya pinnata) protects it from caterpillar herbivory because of deterrence and toxicity. In its natural habitat, however, a newly discovered variety of the invasive diamondback moth (Plutella xylostella) has disarmed this elemental defense. It thrives on plants containing highly toxic Se levels and shows no oviposition or feeding deterrence, in contrast to related varieties. Interestingly, a Se-tolerant wasp (Diadegma insulare) was foundmore » to parasitize the tolerant moth. The insect's Se tolerance mechanism was revealed by X-ray absorption spectroscopy and liquid chromatography--mass spectroscopy, which showed that the Se-tolerant moth and its parasite both accumulate methylselenocysteine, the same form found in the hyperaccumulator plant, whereas related sensitive moths accumulate selenocysteine. The latter is toxic because of its nonspecific incorporation into proteins. Indeed, the Se-tolerant diamondback moth incorporated less Se into protein. Additionally, the tolerant variety sequestered Se in distinct abdominal areas, potentially involved in detoxification and larval defense to predators. Conclusions Although Se hyperaccumulation protects plants from herbivory by some invertebrates, it can give rise to the evolution of unique Se-tolerant herbivores and thus provide a portal for Se into the local ecosystem. In a broader context, this study provides insight into the possible ecological implications of using Se-enriched crops as a source of anti-carcinogenic selenocompounds and for the remediation of Se-polluted environments.« less

Acute toxicity of heavy metals to acetate-utilizing mixed cultures of sulfate-reducing bacteria: EC100 and EC50.

PubMed

Utgikar, V P; Chen, B Y; Chaudhary, N; Tabak, H H; Haines, J R; Govind, R

2001-12-01

Acid mine drainage from abandoned mines and acid mine pit lakes is an important environmental concern and usually contains appreciable concentrations of heavy metals. Because sulfate-reducing bacteria (SRB) are involved in the treatment of acid mine drainage, knowledge of acute metal toxicity levels for SRB is essential for the proper functioning of the treatment system for acid mine drainage. Quantification of heavy metal toxicity to mixed cultures of SRB is complicated by the confounding effects of metal hydroxide and sulfide precipitation, biosorption, and complexation with the constituents of the reaction matrix. The objective of this paper was to demonstrate that measurements of dissolved metal concentrations could be used to determine the toxicity parameters for mixed cultures of sulfate-reducing bacteria. The effective concentration, 100% (EC100), the lowest initial dissolved metal concentrations at which no sulfate reduction is observed, and the effective concentration, 50% (EC50), the initial dissolved metal concentrations resulting in a 50% decrease in sulfate reduction, for copper and zinc were determined in the present study by means of nondestructive, rapid physical and chemical analytical techniques. The reaction medium used in the experiments was designed specifically (in terms of pH and chemical composition) to provide the nutrients necessary for the sulfidogenic activity of the SRB and to preclude chemical precipitation of the metals under investigation. The toxicity-mitigating effects of biosorption of dissolved metals were also quantified. Anaerobic Hungate tubes were set up (at least in triplicate) and monitored for sulfate-reduction activity. The onset of SRB activity was detected by the blackening of the reaction mixture because of formation of insoluble ferrous sulfide. The EC100 values were found to be 12 mg/L for copper and 20 mg/L for zinc. The dissolved metal concentration measurements were effective as the indicators of the effect of the heavy metals at concentrations below EC100. The 7-d EC50 values obtained from the difference between the dissolved metal concentrations for the control tubes (tubes not containing copper or zinc) and tubes containing metals were found to be 10.5 mg/L for copper and 16.5 mg/L for zinc. Measurements of the turbidity and pH, bacterial population estimations by means of a most-probable number technique, and metal recovery in the sulfide precipitate were found to have only a limited applicability in these determinations.

INNOVATIVE IN-SITU REMEDIATION OF CONTAMINATED SEDIMENTS FOR SIMULTANEOUS CONTROL OF CONTAMINATION AND EROSION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knox, A; Michael Paller, M; Danny D. Reible, D

2007-11-28

New technologies are needed that neutralize contaminant toxicity and control physical transport mechanisms that mobilize sediment contaminants. The last 12 months of this comprehensive project investigated the use of combinations of sequestering agents to develop in situ active sediment caps that stabilize mixtures of contaminants and act as a barrier to mechanical disturbance under a broad range of environmental conditions. Efforts focused on the selection of effective sequestering agents for use in active caps, the composition of active caps, and the effects of active cap components on contaminant bioavailability and retention. Results from this project showed that phosphate amendments, somemore » organoclays, and the biopolymer, chitosan, were very effective at removing metals from both fresh and salt water. These amendments also exhibited high retention (80% or more) of most metals indicating reduced potential for remobilization to the water column. Experiments on metal speciation and retention in contaminated sediment showed that apatite and organoclay can immobilize a broad range of metals under both reduced and oxidized conditions. These studies were followed by sequential extractions to evaluate the bioavailability and retention of metals in treated sediments. Metal fractions recovered in early extraction steps are more likely to be bioavailable and were termed the Potentially Mobile Fraction (PMF). Less bioavailable fractions collected in later extraction steps were termed the Recalcitrant Factor (RF). Apatite and organoclay reduced the PMF and increased the RF for several elements, especially Pb, Zn, Ni, Cr, and Cd. Empirically determined partitioning coefficients and modeling studies were used to assess the retention of organic contaminants on selected sequestering agents. Organoclays exhibited exceptionally high sorption of polycyclic aromatic hydrocarbons as indicated by a comparison of K{sub d} values among 12 amendments. These results suggested that organoclays have high potential for controlling organic contaminants. Measured partitioning coefficients were used to model the time required for a contaminant to penetrate sediment caps composed of organoclay. The results showed that a thin layer of highly sorptive organoclay can lead to very long migration times, perhaps longer than the expected lifetime of the contaminant in the sediment environment. A one-dimensional numerical model was used to examine the diffusion of metals through several cap material based on measured and assumed material and transport properties. These studies showed that active caps composed of apatite or organoclay have the potential to delay contaminant breakthrough due to diffusion by hundreds of years or more compared with passive caps composed of sand. Advectively dominated column experiments are currently underway to define effective sorption related retardation factors in promising amendments for various hydrophobic organic compounds. Upon completion of these experiments, advection transient models will be used to estimate the time required for the breakthrough of various contaminants in caps composed of different experimental materials. Biopolymer products for inclusion in active caps were evaluated on the basis of resistance to biodegradation, sorption capacity for organic and inorganic contaminants, and potential for erosion control. More than 20 biopolymer products were evaluated resulting in the selection of chitosan/guar gum cross-linked with borax and xanthan/chitosan cross-linked with calcium chloride for inclusion in active caps to produce a barrier that resists mechanical disturbance. A process was developed for coating sand with cross-linked biopolymers to provide a means for delivery to the sediment surface. Properties of biopolymer coated sand such as carbon fraction (indicating biopolymer coverage), porosity, bulk density, and biodegradability have been evaluated, and experiments are currently underway to assess the resistance of biopolymer coated sand to erosion. Although the ability of active cap materials to remediate contaminants has been emphasized in this study, it is also important to ensure that these materials do not have deleterious effects on the environment. Therefore, promising amendments were evaluated for toxicity using 10 day sediment toxicity tests, the standardized Toxicity Characteristic Leaching Procedure (TCLP), and measurement of metal concentrations in aqueous extracts from the amendments. Metal concentrations were below TCLP limits, EPA ambient water quality criteria, and other ecological screening values These results showed that apatite, organoclay, and biopolymer coated sand do not release metals. The sediment toxicity tests indicated that apatite and biopolymer coated sand are unlikely to adversely affect benthic organisms, even when used in high concentrations.« less

Impact of heavy metals on the female reproductive system.

PubMed

Rzymski, Piotr; Tomczyk, Katarzyna; Rzymski, Pawel; Poniedziałek, Barbara; Opala, Tomasz; Wilczak, Maciej

2015-01-01

It has been recognized that environmental pollution can affect the quality of health of the human population. Heavy metals are among the group of highly emitted contaminants and their adverse effect of living organisms has been widely studied in recent decades. Lifestyle and quality of the ambient environment are among these factors which can mainly contribute to the heavy metals exposure in humans. A review of literature linking heavy metals and the female reproductive system and description of the possible associations with emission and exposure of heavy metals and impairments of female reproductive system according to current knowledge. The potential health disorders caused by chronic or acute heavy metals toxicity include immunodeficiency, osteoporosis, neurodegeneration and organ failures. Potential linkages of heavy metals concentration found in different human organs and blood with oestrogen-dependent diseases such as breast cancer, endometrial cancer, endometriosis and spontaneous abortions, as well as pre-term deliveries, stillbirths and hypotrophy, have also been reported. Environmental deterioration can lead to the elevated risk of human exposure to heavy metals, and consequently, health implications including disturbances in reproduction. It is therefore important to continue the investigations on metal-induced mechanisms of fertility impairment on the genetic, epigenetic and biochemical level.