Recovering heavy rare earth metals from magnet scrap

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

Ott, Ryan T.; McCallum, Ralph W.; Jones, Lawrence L.

A method of treating rare earth metal-bearing permanent magnet scrap, waste or other material in a manner to recover the heavy rare earth metal content separately from the light rare earth metal content. The heavy rare earth metal content can be recovered either as a heavy rare earth metal-enriched iron based alloy or as a heavy rare earth metal based alloy.

Noninvasive evaluation of heavy metal uptake and storage in micoralgae using a fluorescence resonance energy transfer-based heavy metal biosensor.

PubMed

Rajamani, Sathish; Torres, Moacir; Falcao, Vanessa; Ewalt Gray, Jaime; Coury, Daniel A; Colepicolo, Pio; Sayre, Richard

2014-02-01

We have developed a fluorescence resonance energy transfer (FRET)-based heavy metal biosensor for the quantification of bioavailable free heavy metals in the cytoplasm of the microalga Chlamydomonas reinhardtii. The biosensor is composed of an end-to-end fusion of cyan fluorescent protein (CFP), chicken metallothionein II (MT-II), and yellow fluorescent protein (YFP). In vitro measurements of YFP/CFP fluorescence emission ratios indicated that the addition of metals to the purified biosensor enhanced FRET between CFP and YFP, consistent with heavy metal-induced folding of MT-II. A maximum YFP/CFP FRET ratio of 2.8 was observed in the presence of saturating concentrations of heavy metals. The sensitivity of the biosensor was greatest for Hg2+ followed by Cd2+≈Pb2+>Zn2+>Cu2+. The heavy metal biosensor was unresponsive to metals that do not bind to MT-II (Na+ and Mg2+). When expressed in C. reinhardtii, we observed a differential metal-dependent response to saturating external concentrations (1.6 mm) of heavy metals (Pb2+>Cd2+) that was unlike that observed for the isolated biosensor (in vitro). Significantly, analysis of metal uptake kinetics indicated that equilibration of the cytoplasm with externally applied heavy metals occurred within seconds. Our results also indicated that algae have substantial buffering capacity for free heavy metals in their cytosol, even at high external metal concentrations.

Review: Nutritional ecology of heavy metals.

PubMed

Hejna, M; Gottardo, D; Baldi, A; Dell'Orto, V; Cheli, F; Zaninelli, M; Rossi, L

2018-01-08

The aim of this review is to focus the attention on the nutrition ecology of the heavy metals and on the major criticisms related to the heavy metals content in animal feeds, manure, soil and animal-origin products. Heavy metals are metallic elements that have a high density that have progressively accumulated in the food chain with negative effects for human health. Some metals are essential (Fe, I, Co, Zn, Cu, Mn, Mo, Se) to maintain various physiological functions and are usually added as nutritional additives in animal feed. Other metals (As, Cd, F, Pb, Hg) have no established biological functions and are considered as contaminants/undesirable substances. The European Union adopted several measures in order to control their presence in the environment, as a result of human activities such as: farming, industry or food processing and storage contamination. The control of the animal input could be an effective strategy to reduce human health risks related to the consumption of animal-origin products and the environmental pollution by manure. Different management of raw materials and feed, animal species as well as different legal limits can influence the spread of heavy metals. To set up effective strategies against heavy metals the complex interrelationships in rural processes, the widely variability of farming practices, the soil and climatic conditions must be considered. Innovative and sustainable approaches have discussed for the heavy metal nutrition ecology to control the environmental pollution from livestock-related activities.

Selected heavy metals speciation in chemically stabilised sewage sludge

NASA Astrophysics Data System (ADS)

Wiśniowska, Ewa; Włodarczyk-Makuła, Marła

2017-11-01

Selected heavy metals (Pb, Ni, Cd) were analysed in soil, digested sewage sludge as well as in the sludge stabilised with CaO or Fenton's reagent. The dose of Fenton's reagent was as follows: Fe2+ = 1g.L-1, Fe2+/H2O2=1:100; stabilisation lasted for 2 h. Dose of CaO was equal to 1 g CaO.g d.m.-1 Total concentration of all metals in the digested sewage sludge was higher than in the soil. Chemical stabilisation of sludge with Fenton's reagent increased total metal content in the sludge as a result of total solids removal. Opposite effect was stated when the sludge was mixed with CaO. Also chemical fractions of heavy metals were identified (exchangeable, carbonate bound, iron oxides bound, organic and residual). The results indicate that stabilisation of the sludge with Fenton's reagent increased mobility of heavy metals compared to the digested sludge. Amendment of CaO increased percent share of examined metals in residual fraction, thus immobilised them and decreased their bioavailability.

[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.

Analysis of heavy metal sources in soil using kriging interpolation on principal components.

PubMed

Ha, Hoehun; Olson, James R; Bian, Ling; Rogerson, Peter A

2014-05-06

Anniston, Alabama has a long history of operation of foundries and other heavy industry. We assessed the extent of heavy metal contamination in soils by determining the concentrations of 11 heavy metals (Pb, As, Cd, Cr, Co, Cu, Mn, Hg, Ni, V, and Zn) based on 2046 soil samples collected from 595 industrial and residential sites. Principal Component Analysis (PCA) was adopted to characterize the distribution of heavy metals in soil in this region. In addition, a geostatistical technique (kriging) was used to create regional distribution maps for the interpolation of nonpoint sources of heavy metal contamination using geographical information system (GIS) techniques. There were significant differences found between sampling zones in the concentrations of heavy metals, with the exception of the levels of Ni. Three main components explaining the heavy metal variability in soils were identified. The results suggest that Pb, Cd, Cu, and Zn were associated with anthropogenic activities, such as the operations of some foundries and major railroads, which released these heavy metals, whereas the presence of Co, Mn, and V were controlled by natural sources, such as soil texture, pedogenesis, and soil hydrology. In general terms, the soil levels of heavy metals analyzed in this study were higher than those reported in previous studies in other industrial and residential communities.

Heavy Metal Risk Management: Case Analysis

PubMed Central

Kim, Ji Ae; Lee, Seung Ha; Choi, Seung Hyun; Jung, Ki Kyung; Park, Mi Sun; Jeong, Ji Yoon; Hwang, Myung Sil; Yoon, Hae Jung; Choi, Dal Woong

2012-01-01

To prepare measures for practical policy utilization and the control of heavy metals, hazard control related institutions by country, present states of control by country, and present states of control by heavy metals were examined. Hazard control cases by heavy metals in various countries were compared and analyzed. In certain countries (e.g., the U.S., the U.K., and Japan), hazardous substances found in foods (e.g., arsenic, lead, cadmium, and mercury) are controlled. In addition, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) recommends calculating the provisional tolerable weekly intake (PTWI) of individual heavy metals instead of the acceptable daily intake (ADI) to compare their pollution levels considering their toxicity accumulated in the human body. In Korea, exposure assessments have been conducted, and in other countries, hazardous substances are controlled by various governing bodies. As such, in Korea and other countries, diverse food heavy metal monitoring and human body exposure assessments are conducted, and reducing measures are prepared accordingly. To reduce the danger of hazardous substances, many countries provide leaflets and guidelines, develop hazardous heavy metal intake recommendations, and take necessary actions. Hazard control case analyses can assist in securing consumer safety by establishing systematic and reliable hazard control methods. PMID:24278603

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.

Causal inference between bioavailability of heavy metals and environmental factors in a large-scale region.

PubMed

Liu, Yuqiong; Du, Qingyun; Wang, Qi; Yu, Huanyun; Liu, Jianfeng; Tian, Yu; Chang, Chunying; Lei, Jing

2017-07-01

The causation between bioavailability of heavy metals and environmental factors are generally obtained from field experiments at local scales at present, and lack sufficient evidence from large scales. However, inferring causation between bioavailability of heavy metals and environmental factors across large-scale regions is challenging. Because the conventional correlation-based approaches used for causation assessments across large-scale regions, at the expense of actual causation, can result in spurious insights. In this study, a general approach framework, Intervention calculus when the directed acyclic graph (DAG) is absent (IDA) combined with the backdoor criterion (BC), was introduced to identify causation between the bioavailability of heavy metals and the potential environmental factors across large-scale regions. We take the Pearl River Delta (PRD) in China as a case study. The causal structures and effects were identified based on the concentrations of heavy metals (Zn, As, Cu, Hg, Pb, Cr, Ni and Cd) in soil (0-20 cm depth) and vegetable (lettuce) and 40 environmental factors (soil properties, extractable heavy metals and weathering indices) in 94 samples across the PRD. Results show that the bioavailability of heavy metals (Cd, Zn, Cr, Ni and As) was causally influenced by soil properties and soil weathering factors, whereas no causal factor impacted the bioavailability of Cu, Hg and Pb. No latent factor was found between the bioavailability of heavy metals and environmental factors. The causation between the bioavailability of heavy metals and environmental factors at field experiments is consistent with that on a large scale. The IDA combined with the BC provides a powerful tool to identify causation between the bioavailability of heavy metals and environmental factors across large-scale regions. Causal inference in a large system with the dynamic changes has great implications for system-based risk management. Copyright © 2017 Elsevier Ltd. All

[Using sequential indicator simulation method to define risk areas of soil heavy metals in farmland.

PubMed

Yang, Hao; Song, Ying Qiang; Hu, Yue Ming; Chen, Fei Xiang; Zhang, Rui

2018-05-01

The heavy metals in soil have serious impacts on safety, ecological environment and human health due to their toxicity and accumulation. It is necessary to efficiently identify the risk area of heavy metals in farmland soil, which is of important significance for environment protection, pollution warning and farmland risk control. We collected 204 samples and analyzed the contents of seven kinds of heavy metals (Cu, Zn, Pb, Cd, Cr, As, Hg) in Zengcheng District of Guangzhou, China. In order to overcame the problems of the data, including the limitation of abnormal values and skewness distribution and the smooth effect with the traditional kriging methods, we used sequential indicator simulation method (SISIM) to define the spatial distribution of heavy metals, and combined Hakanson index method to identify potential ecological risk area of heavy metals in farmland. The results showed that: (1) Based on the similar accuracy of spatial prediction of soil heavy metals, the SISIM had a better expression of detail rebuild than ordinary kriging in small scale area. Compared to indicator kriging, the SISIM had less error rate (4.9%-17.1%) in uncertainty evaluation of heavy-metal risk identification. The SISIM had less smooth effect and was more applicable to simulate the spatial uncertainty assessment of soil heavy metals and risk identification. (2) There was no pollution in Zengcheng's farmland. Moderate potential ecological risk was found in the southern part of study area due to enterprise production, human activities, and river sediments. This study combined the sequential indicator simulation with Hakanson risk index method, and effectively overcame the outlier information loss and smooth effect of traditional kriging method. It provided a new way to identify the soil heavy metal risk area of farmland in uneven sampling.

Effect of heavy metals on soil fungi

NASA Astrophysics Data System (ADS)

Sosak-Świderska, Bożena

2010-05-01

Fungi constitute a high proportion of the microbial biomass in soil.Being widespread in soil their large surface-to-volume ratio and high metabolic activity, fungi can contribute significantly to heavy metal dynamics in soil. At neutral pH heavy metals in soils tend to be immobilized to precipitation and/or absorption to cation exchange sites of clay minerals. In the acidic soils, metals are more mobile and enter food webs easier. Microbial production of acids and chelating agents can mobilize to toxic metals. Mobilization is often by uptake and intracellular accumulation of the heavy metlas, and in this way, the bioavailability of metals towards other organisms can be more reduced. Fungi were isolated from soils from Upper Silesia in Poland and belonged to widespread genera: Aspergillus, Cladosporium, Penicillium and Trichoderma. Fungi from different taxonomic groups differ greatly in their tolerance to heavy metals. This could be related to their wall structure and chemistry as well as biochemical and physiological characteristics of fungi. Localization of metals in fungal cells was studied using electron microscopy analysis. Metal biosorption in the cell wall can be complex as melanin granules. Fungal vacuoles have an important role in the regulation of the cytosolic concentration of metal ions, and may contribute to heavy metal tolerance.In polluted soils with heavy metals, fungal species composition can be changed and their physiological activity can be changed, too.

Plant rhamnogalacturonan II complexation of heavy metal cations

DOEpatents

O`Neill, M.A.; Pellerin, P.J.M.; Warrenfeltz, D.; Vidal, S.; Darvill, A.G.; Albersheim, P.

1999-03-02

The present invention provides rhamnogalacturonan-II (RG-II) and relates to its ability to complex specific multivalent heavy metal cations. In the presence of boric acid, RG-II monomers form dimers that are cross-linked by a borate ester. The yield of such borate ester cross-linked dimers of RG-II is enhanced in the presence of specific heavy metal cations. The present invention further relates to the utility of RG-II in assays for the detection of specific heavy metal contamination; as a reagent useful in the removal of specific heavy metal cations contaminating foods and liquids, for example, fish, wines, etc.; as a pharmaceutical composition useful as an antidote in specific heavy metal cation poisoning; as a treatment for the detoxification of specific heavy metal cations from blood and/or tissues; and in a method of remediation of waters and soils contaminated with specific heavy metal cations. 15 figs.

Plant rhamnogalacturonan II complexation of heavy metal cations

DOEpatents

O'Neill, Malcolm A.; Pellerin, Patrice J. M.; Warrenfeltz, Dennis; Vidal, Stephane; Darvill, Alan G.; Albersheim, Peter

1999-01-01

The present invention provides rhamnogalacturonan-II (RG-II) and relates to its ability to complex specific multivalent heavy metal cations. In the presence of boric acid, RG-II monomers form dimers that are cross-linked by a borate ester. The yield of such borate ester cross-linked dimers of RG-II is enhanced in the presence of specific heavy metal cations. The present invention further relates to the utility of RG-II in assays for the detection of specific heavy metal contamination; as a reagent useful in the removal of specific heavy metal cations contaminating foods and liquids, for example, fish, wines, etc.; as a pharmaceutical composition useful as an antidote in specific heavy metal cation poisoning; as a treatment for the detoxification of specific heavy metal cations from blood and/or tissues; and in a method of remediation of waters and soils contaminated with specific heavy metal cations.

Heavy Metal Uptake by Novel Miscanthus Seed-Based Hybrids Cultivated in Heavy Metal Contaminated Soil

NASA Astrophysics Data System (ADS)

Krzyżak, Jacek; Pogrzeba, Marta; Rusinowski, Szymon; Clifton-Brown, John; McCalmont, Jon Paul; Kiesel, Andreas; Mangold, Anja; Mos, Michal

2017-09-01

When heavy metal contaminated soils are excluded from food production, biomass crops offer an alternative commercial opportunity. Perennial crops have potential for phytoremediation. Whilst the conditions at heavy metal contaminated sites are challenging, successful phytoremediation would bring significant economic and social benefits. Seed-based Miscanthus hybrids were tested alongside the commercial clone Miscanthus × giganteus on arable land, contaminated with Pb, Cd and Zn near Katowice. Before the randomized experimental plots were established (25m2 plots with plant density 2/m2) `time-zero' soil samples were taken to determine initial levels of total (aqua regia) and bioavailable (CaCl2 extraction) concentration of Pb, Cd and Zn. After the growing season plant material was sampled during autumn (October, green harvest) and winter (March, brown harvest) to determine differences in heavy metal uptake. Results after the first growing season are presented, including the plot establishment success, biomass yield and heavy metal uptake.

An Integrated H-G Scheme Identifying Areas for Soil Remediation and Primary Heavy Metal Contributors: A Risk Perspective.

PubMed

Zou, Bin; Jiang, Xiaolu; Duan, Xiaoli; Zhao, Xiuge; Zhang, Jing; Tang, Jingwen; Sun, Guoqing

2017-03-23

Traditional sampling for soil pollution evaluation is cost intensive and has limited representativeness. Therefore, developing methods that can accurately and rapidly identify at-risk areas and the contributing pollutants is imperative for soil remediation. In this study, we propose an innovative integrated H-G scheme combining human health risk assessment and geographical detector methods that was based on geographical information system technology and validated its feasibility in a renewable resource industrial park in mainland China. With a discrete site investigation of cadmium (Cd), arsenic (As), copper (Cu), mercury (Hg) and zinc (Zn) concentrations, the continuous surfaces of carcinogenic risk and non-carcinogenic risk caused by these heavy metals were estimated and mapped. Source apportionment analysis using geographical detector methods further revealed that these risks were primarily attributed to As, according to the power of the determinant and its associated synergic actions with other heavy metals. Concentrations of critical As and Cd, and the associated exposed CRs are closed to the safe thresholds after remediating the risk areas identified by the integrated H-G scheme. Therefore, the integrated H-G scheme provides an effective approach to support decision-making for regional contaminated soil remediation at fine spatial resolution with limited sampling data over a large geographical extent.

Phytomining of heavy metals from soil by Hibiscus radiatus using phytoremediationtechnology (Part-2)

NASA Astrophysics Data System (ADS)

Panchal, K. J.; Subramanian, R. B.; Gohil, T. P.

2017-12-01

Metal ions are not only valuable intermediates in metal extraction, but also important raw materials fortechnical applications. They possess some unique but, identical physical and chemical properties, whichmake them useful probes of low temperature geochemical reactions. Heavy metals are natural constituentsof the earth's crust, but indiscriminate human activities have drastically altered their geochemical cyclesand biochemical balance. Metal concentration in soil typically ranges from less than one to as high as100,000 mg/kg. Heavy metal contaminations of land resources continue to be the focus of numerousenvironmental studies and attract a great deal of attention worldwide. This is attributed to nobiodegradabilityand persistence of heavy metals in soils. Prolonged exposure to heavy metals such ascadmium, copper, lead, nickel, and zinc can cause deleterious health effects in humans. Complexation,separation, and removal of metal ions have become increasingly attractive areas of research and have ledto new technical developments like phytoremediation that has numerous biotechnological implications ofunderstanding of plant metal accumulation. Hibiscus radiatus is newly identified as a potential heavymetal hypreaccumulator. In this study Hibiscus radiatus was subjected for in vitro heavy metalaccumulation, to explore the accumulation pattern of four heavy metals viz Cadmium, Lead, Nickel andZinc in various parts of Hibiscus radiatus plant parts. Translocation of metals in Hibiscus radiatus plant parts from soil makes this plant an eligible candidate to remove heavy metals from soil.

The Heavy Metal Subculture and Suicide.

ERIC Educational Resources Information Center

Stack, Steven; And Others

1994-01-01

Assessed relationship between heavy metal music and suicide with data on heavy metal magazine subscriptions and youth suicide in 50 states. Found that, controlling for other predictors of suicide, greater strength of metal subculture, higher youth suicide rate, suggests that music perhaps nurtures suicidal tendencies already present in subculture.…

Heavy metals contamination and their risk assessment around the abandoned base metals and Au-Ag mines in Korea

NASA Astrophysics Data System (ADS)

Chon, Hyo-Taek

2017-04-01

Heavy metals contamination in the areas of abandoned Au-Ag and base metal mines in Korea was investigated in order to assess the level of metal pollution, and to draw general summaries about the fate of toxic heavy metals in different environments. Efforts have been made to compare the level of heavy metals, chemical forms, and plant uptake of heavy metals in each mine site. In the base-metals mine areas, significant levels of Cd, Cu, Pb and Zn were found in mine dump soils developed over mine waste materials and tailings. Leafy vegetables tend to accumulate heavy metals(in particular, Cd and Zn) higher than other crop plants, and high metal concentrations in rice crops may affect the local residents' health. In the Au-Ag mining areas, arsenic would be the most characteristic contaminant in the nearby environment. Arsenic and heavy metals were found to be mainly associated with sulfide gangue minerals, and the mobility of these metals would be enhanced by the effect of continuing weathering and oxidation. According to the sequential extraction of metals in soils, most heavy metals were identified as non-residual chemical forms, and those are very susceptible to the change of ambient conditions of a nearby environment. The concept of pollution index(PI) of soils gives important information on the extent and degree of multi-element contamination, and can be applied to the evaluation of mine soils before their agricultural use and remediation. The risk assessment process comprising exposure assessment, dose-response assessment, and risk characterization was discussed, and the results of non-cancer risk of As, Cd, and Zn, and those of cancer risk of As were suggested.

Multivariate statistical and lead isotopic analyses approach to identify heavy metal sources in topsoil from the industrial zone of Beijing Capital Iron and Steel Factory.

PubMed

Zhu, Guangxu; Guo, Qingjun; Xiao, Huayun; Chen, Tongbin; Yang, Jun

2017-06-01

than the natural sources. Our study could not only reveal the overall situation of heavy metal contamination, but also identify the specific pollution sources.

Whole-genome transcriptional analysis of heavy metal stresses inCaulobacter crescentus

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

Hu, Ping; Brodie, Eoin L.; Suzuki, Yohey

2005-09-21

The bacterium Caulobacter crescentus and related stalkbacterial species are known for their distinctive ability to live in lownutrient environments, a characteristic of most heavy metal contaminatedsites. Caulobacter crescentus is a model organism for studying cell cycleregulation with well developed genetics. We have identified the pathwaysresponding to heavy metal toxicity in C. crescentus to provide insightsfor possible application of Caulobacter to environmental restoration. Weexposed C. crescentus cells to four heavy metals (chromium, cadmium,selenium and uranium) and analyzed genome wide transcriptional activitiespost exposure using a Affymetrix GeneChip microarray. C. crescentusshowed surprisingly high tolerance to uranium, a possible mechanism forwhich may be formationmore » of extracellular calcium-uranium-phosphateprecipitates. The principal response to these metals was protectionagainst oxidative stress (up-regulation of manganese-dependent superoxidedismutase, sodA). Glutathione S-transferase, thioredoxin, glutaredoxinsand DNA repair enzymes responded most strongly to cadmium and chromate.The cadmium and chromium stress response also focused on reducing theintracellular metal concentration, with multiple efflux pumps employed toremove cadmium while a sulfate transporter was down-regulated to reducenon-specific uptake of chromium. Membrane proteins were also up-regulatedin response to most of the metals tested. A two-component signaltransduction system involved in the uranium response was identified.Several differentially regulated transcripts from regions previously notknown to encode proteins were identified, demonstrating the advantage ofevaluating the transcriptome using whole genome microarrays.« less

Bioremoval of heavy metals by bacterial biomass.

PubMed

Aryal, Mahendra; Liakopoulou-Kyriakides, Maria

2015-01-01

Heavy metals are among the most common pollutants found in the environment. Health problems due to the heavy metal pollution become a major concern throughout the world, and therefore, various treatment technologies such as reverse osmosis, ion exchange, solvent extraction, chemical precipitation, and adsorption are adopted to reduce or eliminate their concentration in the environment. Biosorption is a cost-effective and environmental friendly technique, and it can be used for detoxification of heavy metals in industrial effluents as an alternative treatment technology. Biosorption characteristics of various bacterial species are reviewed here with respect to the results reported so far. The role of physical, chemical, and biological modification of bacterial cells for heavy metal removal is presented. The paper evaluates the different kinetic, equilibrium, and thermodynamic models used in bacterial sorption of heavy metals. Biomass characterization and sorption mechanisms as well as elution of metal ions and regeneration of biomass are also discussed.

Heavy Metal Content in Terraced Rice Fields at Sruwen Tengaran Semarang - Indonesia

NASA Astrophysics Data System (ADS)

Hindarwati, Yulis; Soeprobowati, Tri Retnaningsih; Sudarno

2018-02-01

The presence of heavy metal on agricultural soils can be caused not only natural factors but also due to human intervention. Differences in management and lack of understanding of farmers in the production input of fertilizers and pesticides ensued in land ravaged. Periodic testing of paddy fields is necessary to minimize the contaminants from being absorbed by plants that will have an impact on health decline. The purpose of the assessment was to identify the heavy metal content in the terraced rice field in Sruwen Village, Tengaran District, Semarang Regency. Survey was conducted in February 2017. Sampling on terraced rice fields of different heights consisted of upper, middle, and upper down. Taken as many as eight single points and composed at a depth of 0-20 cm and 20-40 cm. The identification results showed that heavy metal content of Pb, Cd, and Cu were present at all altitudes. Heavy Metals Pb and Cd at a depth of 0-20 cm were higher from 20-40 cm in the upper and lower rice fields but lower in the middle rice field. Cu heavy metal at a depth of 0-20 cm was higher than 20-40 cm in all altitude land. The heavy metal content of Pb, Cd, and Cu was still below the heavy metal standard set by the European Union and India.

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.

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.

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.

Assessment of Heavy Metal Pollution in Topsoil around Beijing Metropolis

PubMed Central

Sun, Ranhao; Chen, Liding

2016-01-01

The topsoil around Beijing metropolis, China, is experiencing impacts of rapid urbanization, intensive farming, and extensive industrial emissions. We analyzed the concentrations of Cu, Ni, Pb, Zn, Cd, and Cr from 87 topsoil samples in the pre-rainy season and 115 samples in the post-rainy season. These samples were attributed to nine land use types: forest, grass, shrub, orchard, wheat, cotton, spring maize, summer maize, and mixed farmland. The pollution index (PI) of heavy metals was calculated from the measured and background concentrations. The ecological risk index (RI) was assessed based on the PI values and toxic-response parameters. The results showed that the mean PI values of Pb, Cr, and Cd were > 1 while those of Cu, Ni, and Zn were < 1. All the samples had low ecological risk for Cu, Ni, Pb, Zn, and Cr while only 15.35% of samples had low ecological risk for Cd. Atmospheric transport rather than land use factors best explained the seasonal variations in heavy metal concentrations and the impact of atmospheric transport on heavy metal concentrations varied according to the heavy metal types. The concentrations of Cu, Cd, and Cr decreased from the pre- to post-rainy season, while those of Ni, Pb, and Zn increased during this period. Future research should be focused on the underlying atmospheric processes that lead to these spatial and seasonal variations in heavy metals. The policymaking on environmental management should pay close attention to potential ecological risks of Cd as well as identifying the transport pathways of different heavy metals. PMID:27159454

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 �

Stabilization of heavy metals in sludge ceramsite.

PubMed

Xu, G R; Zou, J L; Li, G B

2010-05-01

This paper attempts to investigate the stabilization behaviours of heavy metals in ceramsite made from wastewater treatment sludge (WWTS) and drinking-water treatment sludge (DWTS). Leaching tests were conducted to find out the effects of sintering temperature, (Fe(2)O(3) + CaO + MgO)/(SiO(2) + Al(2)O(3)) (defined as F/SA ratios), pH, and oxidative condition. Results show that sintering exhibits good binding capacity for Cd, Cr, Cu, and Pb in ceramsite and leaching contents of heavy metals will not change above 1000 degrees C. The main crystalline phases in ceramsite sintered at 1000 degrees C are kyanite, quartz, Na-Ca feldspars, sillimanite, and enstatite. The main compounds of heavy metals are crocoite, chrome oxide, cadmium silicate, and copper oxide. Leaching contents of Cd, Cu, and Pb increase as the F/SA ratios increase. Heavy metals in ceramsite with variation of F/SA ratios are also in same steady forms, which prove that stronger chemical bonds are formed between these heavy metals and the components. Leaching contents of heavy metals decrease as pH increases and increase as H(2)O(2) concentration increases. The results indicate that when subjected to rigorous leaching conditions, the crystalline structures still exhibit good chemical binding capacity for heavy metals. In conclusion, it is environmentally safe to use ceramsite in civil and construction fields. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

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

Heavy metal content of combustible municipal solid waste in Denmark.

PubMed

Riber, Christian; Fredriksen, Gry S; Christensen, Thomas H

2005-04-01

Data on the heavy metal composition of outlets from Danish incinerators was used to estimate the concentration of Zn, Cu, Pb, Cr, Ni, Cd, As and Hg in combustible waste (wet as received) at 14 Danish incinerators, representing about 80% of the waste incinerated in Denmark. Zn (1020 mg kg(-1)), Cu (620 mg kg(-1)) and Pb (370 mg kg(-1)) showed the highest concentration, whereas Hg (0.6 mg kg(-1)) showed the lowest concentration. The variation among the incinerators was in most cases within a factor of two to three, except for Cr that in two cases showed unexplained high concentrations. The fact that the data represent many incinerators and, in several cases, observations from a period of 4 to 5 years provides a good statistical basis for evaluating the content of heavy metals in combustible Danish waste. Such data may be used for identifying incinerators receiving waste with high concentrations of heavy metals suggesting the introduction of source control, or, if repeated in time, the data must also be used for monitoring the impacts of national regulation controlling heavy metals. It is recommended that future investigations consider the use of sample digestion methods that ensure complete digestion in order to use the data for determining the total heavy metal content of waste.

In situ distributions and characteristics of heavy metals in full-scale landfill layers.

PubMed

He, Pin-Jing; Xiao, Zheng; Shao, Li-Ming; Yu, Ji-Yu; Lee, Duu-Jong

2006-10-11

The leachate from methanogenic landfill normally contains low concentrations of heavy metals. Little samples had ever been collected from the full-scale landfill piles owing to technical difficulty for well drilling. We drilled two wells in Hangzhou Tianziling landfill, 20 m and 32 m in depth each, and collected solid samples of waste age of 1-4 years from both wells. The total amounts, the sequentially extracted amounts, and the chemical binding forms of heavy metals of the samples collected at different depths were measured. With the correlation between leachate production amount and the yearly rainfall amount, the leached ratio of the heavy metals were estimated only 0.13%, 1.8%, 0.15%, and 0.19% of Cu, Cd, Pb, and Zn, respectively. The heavy metals amounts in the main compositions of MSW, like glass, food waste, paper, coal cinders, were measured using fresh MSW samples. Afterward, the contents of heavy metals initially landfilled were estimated. A positive correlation was noted between the measured and the estimated initial contents of heavy metals, indicating that the low migration of heavy metals in landfill layers. However, among the metals investigated, Zn has shown better mobility inside landfill layers. Acid volatile sulfide (AVS) and the simultaneously extracted metals (SEM) were measured for all collected samples with optimal reaction conditions identified to yield nearly perfect sulfide recovery as follows: 100 g wet samples, 80 mL min(-1) N(2) flow rate, reaction time of 150 min. The SEM/AVS ratios ranged 25-45, indicating that the AVS was insufficient to immobilize the SEM. Sequential extraction using six-fraction scheme revealed that the sum of exchangeable and the avid soluble fractions of heavy metals follow: Zn>Cd>Cu, Ni, Pb>Cr. The insoluble fraction of heavy metals in MSW was high, for instance, over 80% for Cr and Pb high insoluble fractions of heavy metals in the landfilled MSW and the sorption capability of the methanogenic landfill layers

Using biochar for remediation of soils contaminated with heavy metals and organic pollutants.

PubMed

Zhang, Xiaokai; Wang, Hailong; He, Lizhi; Lu, Kouping; Sarmah, Ajit; Li, Jianwu; Bolan, Nanthi S; Pei, Jianchuan; Huang, Huagang

2013-12-01

Soil contamination with heavy metals and organic pollutants has increasingly become a serious global environmental issue in recent years. Considerable efforts have been made to remediate contaminated soils. Biochar has a large surface area, and high capacity to adsorb heavy metals and organic pollutants. Biochar can potentially be used to reduce the bioavailability and leachability of heavy metals and organic pollutants in soils through adsorption and other physicochemical reactions. Biochar is typically an alkaline material which can increase soil pH and contribute to stabilization of heavy metals. Application of biochar for remediation of contaminated soils may provide a new solution to the soil pollution problem. This paper provides an overview on the impact of biochar on the environmental fate and mobility of heavy metals and organic pollutants in contaminated soils and its implication for remediation of contaminated soils. Further research directions are identified to ensure a safe and sustainable use of biochar as a soil amendment for remediation of contaminated soils.

Biosorption of Heavy Metals from Aqueous Solution by Bacteria Isolated from Contaminated Soil.

PubMed

Dhanwal, Pradeep; Kumar, Anil; Dudeja, Shruti; Badgujar, Hemlata; Chauhan, Rohit; Kumar, Abhishek; Dhull, Poonam; Chhokar, Vinod; Beniwal, Vikas

2018-05-01

  This study was carried out to analyze the heavy metals biosorption potential of bacteria isolated from soil contaminated with electroplating industrial effluents. Bacterial isolates were screened for their multi-metal biosorption potential against copper, nickel, lead, and chromium. Bacterial isolate CU4A showed the maximum uptake of copper, nickel, lead, and chromium in aqueous solution, with a biosorption efficiency of 87.16 %, 79.62%, 84.92%, and 68.12%, respectively. The bacterial strain CU4A was identified as Bacillus cereus, following 16S rRNA gene sequence analysis. The surface chemical functional groups of bacterial biomass were identified by Fourier transform infrared (FTIR) spectroscopy as hydroxyl, carboxyl, amine, and halide, which may be involved in the biosorption of heavy metals. Analysis with scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) confirmed the adsorption of metals on the bacterial cell mass. The results of this study are significant and could be further investigated for the removal of heavy metals from contaminated environments.

Effects of heavy metals on soil microbial community

NASA Astrophysics Data System (ADS)

Chu, Dian

2018-02-01

Soil is one of the most important environmental natural resources for human beings living, which is of great significance to the quality of ecological environment and human health. The study of the function of arable soil microbes exposed to heavy metal pollution for a long time has a very important significance for the usage of farmland soil. In this paper, the effects of heavy metals on soil microbial community were reviewed. The main contents were as follows: the effects of soil microbes on soil ecosystems; the effects of heavy metals on soil microbial activity, soil enzyme activities and the composition of soil microbial community. In addition, a brief description of main methods of heavy metal detection for soil pollution is given, and the means of researching soil microbial community composition are introduced as well. Finally, it is concluded that the study of soil microbial community can well reflect the degree of soil heavy metal pollution and the impact of heavy metal pollution on soil ecology.

Effects of Listening to Heavy Metal Music on College Women: A Pilot Study

ERIC Educational Resources Information Center

Becknell, Milton E.; Firmin, Michael W.; Hwang, Chi-en; Fleetwood, David M.; Tate, Kristie L.; Schwab, Gregory D.

2008-01-01

College students are typically very identified with popular music and spend many hours listening to their music of preference. To investigate the effects of heavy metal music, we compared the responses of 18 female undergraduate college students to a baseline silence condition (A) and a heavy metal music condition (B). Dependent measures included:…

Heavy Metal, Religiosity, and Suicide Acceptability.

ERIC Educational Resources Information Center

Stack, Steven

1998-01-01

Reports on data taken from the General Social Survey that found a link between "heavy metal" rock fanship and suicide acceptability. Finds that relationship becomes nonsignificant once level of religiosity is controlled. Heavy metal fans are low in religiosity, which contributes to greater suicide acceptability. (Author/JDM)

Heavy metal contamination from geothermal sources.

PubMed Central

Sabadell, J E; Axtmann, R C

1975-01-01

Liquid-dominated hydrothermal reservoirs, which contain saline fluids at high temperatures and pressures, have a significant potential for contamination of the environment by heavy metals. The design of the power conversion cycle in a liquid-dominated geothermal plant is a key factor in determining the impact of the installation. Reinjection of the fluid into the reservoir minimizes heavy metal effluents but is routinely practiced at few installations. Binary power cycles with reinjection would provide even cleaner systems but are not yet ready for commercial application. Vapor-dominated systems, which contain superheated steam, have less potential for contamination but are relatively uncommon. Field data on heavy metal effluents from geothermal plants are sparse and confounded by contributions from "natural" sources such as geysers and hot springs which often exist nearby. Insofar as geothermal power supplies are destined to multiply, much work is required on their environmental effects including those caused by heavy metals. PMID:1227849

Heavy metal contamination from geothermal sources.

PubMed

Sabadell, J E; Axtmann, R C

1975-12-01

Liquid-dominated hydrothermal reservoirs, which contain saline fluids at high temperatures and pressures, have a significant potential for contamination of the environment by heavy metals. The design of the power conversion cycle in a liquid-dominated geothermal plant is a key factor in determining the impact of the installation. Reinjection of the fluid into the reservoir minimizes heavy metal effluents but is routinely practiced at few installations. Binary power cycles with reinjection would provide even cleaner systems but are not yet ready for commercial application. Vapor-dominated systems, which contain superheated steam, have less potential for contamination but are relatively uncommon. Field data on heavy metal effluents from geothermal plants are sparse and confounded by contributions from "natural" sources such as geysers and hot springs which often exist nearby. Insofar as geothermal power supplies are destined to multiply, much work is required on their environmental effects including those caused by heavy metals.

Heavy metal contamination of soil and water in the vicinity of an abandoned e-waste recycling site: implications for dissemination of heavy metals.

PubMed

Wu, Qihang; Leung, Jonathan Y S; Geng, Xinhua; Chen, Shejun; Huang, Xuexia; Li, Haiyan; Huang, Zhuying; Zhu, Libin; Chen, Jiahao; Lu, Yayin

2015-02-15

Illegal e-waste recycling activity has caused heavy metal pollution in many developing countries, including China. In recent years, the Chinese government has strengthened enforcement to impede such activity; however, the heavy metals remaining in the abandoned e-waste recycling site can still pose ecological risk. The present study aimed to investigate the concentrations of heavy metals in soil and water in the vicinity of an abandoned e-waste recycling site in Longtang, South China. Results showed that the surface soil of the former burning and acid-leaching sites was still heavily contaminated with Cd (>0.39 mg kg(-1)) and Cu (>1981 mg kg(-1)), which exceeded their respective guideline levels. The concentration of heavy metals generally decreased with depth in both burning site and paddy field, which is related to the elevated pH and reduced TOM along the depth gradient. The pond water was seriously acidified and contaminated with heavy metals, while the well water was slightly contaminated since heavy metals were mostly retained in the surface soil. The use of pond water for irrigation resulted in considerable heavy metal contamination in the paddy soil. Compared with previous studies, the reduced heavy metal concentrations in the surface soil imply that heavy metals were transported to the other areas, such as pond. Therefore, immediate remediation of the contaminated soil and water is necessary to prevent dissemination of heavy metals and potential ecological disaster. Copyright © 2014 Elsevier B.V. All rights reserved.

Modeling of Heavy Metal Transformation in Soil Ecosystem

NASA Astrophysics Data System (ADS)

Kalinichenko, Kira; Nikovskaya, Galina N.

2017-04-01

The intensification of industrial activity leads to an increase in heavy metals pollution of soils. In our opinion, sludge from biological treatment of municipal waste water, stabilized under aerobic-anaerobic conditions (commonly known as biosolid), may be considered as concentrate of natural soil. In their chemical, physical and chemical and biological properties these systems are similar gel-like nanocomposites. These contain microorganisms, humic substances, clay, clusters of nanoparticles of heavy metal compounds, and so on involved into heteropolysaccharides matrix. It is known that microorganisms play an important role in the transformation of different nature substances in soil and its health maintenance. The regularities of transformation of heavy metal compounds in soil ecosystem were studied at the model of biosolid. At biosolid swelling its structure changing (gel-sol transition, weakening of coagulation contacts between metal containing nanoparticles, microbial cells and metabolites, loosening and even destroying of the nanocomposite structure) can occur [1, 2]. The promotion of the sludge heterotrophic microbial activities leads to solubilization of heavy metal compounds in the system. The microbiological process can be realized in alcaligeneous or acidogeneous regimes in dependence on the type of carbon source and followed by the synthesis of metabolites with the properties of flocculants and heavy metals extragents [3]. In this case the heavy metals solubilization (bioleaching) in the form of nanoparticles of hydroxycarbonate complexes or water soluble complexes with oxycarbonic acids is observed. Under the action of biosolid microorganisms the heavy metals-oxycarbonic acids complexes can be transformed (catabolised) into nano-sizing heavy metals- hydroxycarbonates complexes. These ecologically friendly complexes and microbial heteropolysaccharides are able to interact with soil colloids, stay in the top soil profile, and improve soil structure due

Toenail as a biomarker of heavy metal exposure via drinking water: a systematic review.

PubMed

Ab Razak, Nurul Hafiza; Praveena, Sarva Mangala; Hashim, Zailina

2015-01-01

Toenail is metabolic end product of the skin, which can provide information about heavy metal accumulation in human cells. Slow growth rates of toenail can represent heavy metal exposure from 2 to 12 months before the clipping. The toenail is a non-invasive biomarker that is easy to collect and store and is stable over time. In this systematic review, the suitability of toenail as a long-term biomarker was reviewed, along with the analysis and validation of toenail and confounders to heavy metal. This systematic review has included 30 articles chosen from a total of 132 articles searched from online electronic databases like Pubmed, Proquest, Science Direct, and SCOPUS. Keywords used in the search included "toenail", "biomarker", "heavy metal", and "drinking water". Heavy metal in toenail can be accurately analyzed using an ICP-MS instrument. The validation of toenail heavy metal concentration data is very crucial; however, the Certified Reference Material (CRM) for toenail is still unavailable. Usually, CRM for hair is used in toenail studies. Confounders that have major effects on heavy metal accumulation in toenail are dietary intake of food and supplement, smoking habit, and overall health condition. This review has identified the advantages and limitations of using toenail as a biomarker for long-term exposure, which can help future researchers design a study on heavy metal exposure using toenail.

Functional Expression of a Bacterial Heavy Metal Transporter in Arabidopsis Enhances Resistance to and Decreases Uptake of Heavy Metals1[w

PubMed Central

Lee, Joohyun; Bae, Hyunju; Jeong, Jeeyon; Lee, Jae-Yun; Yang, Young-Yell; Hwang, Inhwan; Martinoia, Enrico; Lee, Youngsook

2003-01-01

Large parts of agricultural soil are contaminated with lead (Pb) and cadmium (Cd). Although most environments are not heavily contaminated, the low levels observed nonetheless pose a high risk of heavy metal accumulation in the food chain. Therefore, approaches to develop plants with reduced heavy metal uptake are important. Recently, many transgenic plants with increased heavy metal resistance and uptake of heavy metals were developed for the purpose of phytoremediation. However, to reduce heavy metal in the food chain, plants that transfer less heavy metals to the shoot are required. We tested whether an Escherichia coli gene, ZntA, which encodes a Pb(II)/Cd(II)/Zn(II) pump, could be useful for developing plants with reduced heavy metal content. Yeast cells transformed with this gene had improved resistance to Pb(II) and Cd(II). In Arabidopsis plants transformed with ZntA, ZntA was localized at the plasma membrane and improved the resistance of the plants to Pb(II) and Cd(II). The shoots of the transgenic plants had decreased Pb and Cd content. Moreover, the transgenic protoplasts showed lower accumulation of Cd and faster release of preloaded Cd than wild-type protoplasts. These results show that a bacterial transporter gene, ZntA, can be functionally expressed in plant cells, and that that it may be useful for the development of crop plants that are safe from heavy metal contamination. PMID:14512517

Partition of heavy metals in a tropical river system impacted by municipal waste.

PubMed

Duc, Trinh Anh; Loi, Vu Duc; Thao, Ta Thi

2013-02-01

A research program was established to identify the governing factors for the partition coefficient (K(D)) of heavy metals between suspended particulate and dissolved phases in the Day River system a tropical, highly alluvial aquatic system, in Vietnam. The targeted river system, draining an urbanized-industrialized catchment where discharged wastewater is mostly untreated, could be separated into the least impacted, pristine area, and the most impacted, polluted area. Organic matter degradation was shown to govern the variation of parameters like total organic carbon, biochemical oxygen demand, chemical oxygen demand, nutrients, conductivity, or redox potential. Heavy metals in both dissolved and particulate phases were enriched in severely polluted area because of wastewater inflow that contains concentrated metals and intensification of metal influx from sediment. Results show log K(D) in the order Mn < As < Zn < Hg < Ni < Cu < Cd < Co < Pb < Cr < Fe and As < Zn < Ni < Mn < Cr < Cu < Co < Fe in the polluted zone and the pristine zone, respectively. A decreasing tendency of partition coefficients of 11 heavy metals considered from the pristine to the impacted zones was observed. Three explanations for the difference are: (1) increase of solubility of most heavy metals in low redox potential, (2) competition for the binding sites with major and minor cations, and (3) complexation with dissolved organic matter concentrated in municipal waste impacted water. Apart from domestic waste impact, statistical analysis has contributed to identify the influence of climate condition and hydrological regime to the partition of heavy metals in the area.

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.

Noninvasive Evaluation of Heavy Metal Uptake and Storage in Micoralgae Using a Fluorescence Resonance Energy Transfer-Based Heavy Metal Biosensor1[C][W][OPEN

PubMed Central

Rajamani, Sathish; Torres, Moacir; Falcao, Vanessa; Ewalt Gray, Jaime; Coury, Daniel A.; Colepicolo, Pio; Sayre, Richard

2014-01-01

We have developed a fluorescence resonance energy transfer (FRET)-based heavy metal biosensor for the quantification of bioavailable free heavy metals in the cytoplasm of the microalga Chlamydomonas reinhardtii. The biosensor is composed of an end-to-end fusion of cyan fluorescent protein (CFP), chicken metallothionein II (MT-II), and yellow fluorescent protein (YFP). In vitro measurements of YFP/CFP fluorescence emission ratios indicated that the addition of metals to the purified biosensor enhanced FRET between CFP and YFP, consistent with heavy metal-induced folding of MT-II. A maximum YFP/CFP FRET ratio of 2.8 was observed in the presence of saturating concentrations of heavy metals. The sensitivity of the biosensor was greatest for Hg2+ followed by Cd2+ ≈ Pb2+ > Zn2+ > Cu2+. The heavy metal biosensor was unresponsive to metals that do not bind to MT-II (Na+ and Mg2+). When expressed in C. reinhardtii, we observed a differential metal-dependent response to saturating external concentrations (1.6 mm) of heavy metals (Pb2+ > Cd2+) that was unlike that observed for the isolated biosensor (in vitro). Significantly, analysis of metal uptake kinetics indicated that equilibration of the cytoplasm with externally applied heavy metals occurred within seconds. Our results also indicated that algae have substantial buffering capacity for free heavy metals in their cytosol, even at high external metal concentrations. PMID:24368336

The respective effects of soil heavy metal fractions by sequential extraction procedure and soil properties on the accumulation of heavy metals in rice grains and brassicas.

PubMed

Xiao, Ling; Guan, Dongsheng; Peart, M R; Chen, Yujuan; Li, Qiqi

2017-01-01

This study was carried out to examine heavy metal accumulation in rice grains and brassicas and to identify the different controls, such as soil properties and soil heavy metal fractions obtained by the Community Bureau of Reference (BCR) sequential extraction, in their accumulation. In Guangdong Province, South China, rice grain and brassica samples, along with their rhizospheric soil, were collected from fields on the basis of distance downstream from electroplating factories, whose wastewater was used for irrigation. The results showed that long-term irrigation using the electroplating effluent has not only enriched the rhizospheric soil with Cd, Cr, Cu, and Zn but has also increased their mobility and bioavailability. The average concentrations of Cd and Cr in rice grains and brassicas from closest to the electroplating factories were significantly higher than those from the control areas. Results from hybrid redundancy analysis (hRDA) and redundancy analysis (RDA) showed that the BCR fractions of soil heavy metals could explain 29.0 and 46.5 % of total eigenvalue for heavy metal concentrations in rice grains and brassicas, respectively, while soil properties could only explain 11.1 and 33.4 %, respectively. This indicated that heavy metal fractions exerted more control upon their concentrations in rice grains and brassicas than soil properties. In terms of metal interaction, an increase of residual Zn in paddy soil or a decrease of acid soluble Cd in the brassica soil could enhance the accumulation of Cd, Cu, Cr, and Pb in both rice grains and brassicas, respectively, while the reducible or oxidizable Cd in soil could enhance the plants' accumulation of Cr and Pb. The RDA showed an inhibition effect of sand content and CFO on the accumulation of heavy metals in rice grains and brassicas. Moreover, multiple stepwise linear regression could offer prediction for Cd, Cu, Cr, and Zn concentrations in the two crops by soil heavy metal fractions and soil properties.

Hydroponics reducing effluent's heavy metals discharge.

PubMed

Rababah, Abdellah; Al-Shuha, Ahmad

2009-01-01

This paper investigates the capacity of Nutrient Film Technique (NFT) to control effluent's heavy metals discharge. A commercial hydroponic system was adapted to irrigate lettuces with primary treated wastewater for studying the potential heavy metals removal. A second commercial hydroponic system was used to irrigate the same type of lettuces with nutrient solution and this system was used as a control. Results showed that lettuces grew well when irrigated with primary treated effluent in the commercial hydroponic system. The NFT-plant system heavy metals removal efficiency varied amongst the different elements, The system's removal efficiency for Cr was more than 92%, Ni more than 85%, in addition to more than 60% reduction of B, Pb, and Zn. Nonetheless, the NFT-plants system removal efficiencies for As, Cd and Cu were lower than 30%. Results show that lettuces accumulated heavy metals in leaves at concentrations higher than the maximum acceptable European and Australian levels. Therefore, non-edible plants such as flowers or pyrethrum are recommended as value added crops for the proposed NFT.

Phytoremediation of heavy metals--concepts and applications.

PubMed

Ali, Hazrat; Khan, Ezzat; Sajad, Muhammad Anwar

2013-05-01

The mobilization of heavy metals by man through extraction from ores and processing for different applications has led to the release of these elements into the environment. Since heavy metals are nonbiodegradable, they accumulate in the environment and subsequently contaminate the food chain. This contamination poses a risk to environmental and human health. Some heavy metals are carcinogenic, mutagenic, teratogenic and endocrine disruptors while others cause neurological and behavioral changes especially in children. Thus remediation of heavy metal pollution deserves due attention. Different physical and chemical methods used for this purpose suffer from serious limitations like high cost, intensive labor, alteration of soil properties and disturbance of soil native microflora. In contrast, phytoremediation is a better solution to the problem. Phytoremediation is the use of plants and associated soil microbes to reduce the concentrations or toxic effects of contaminants in the environments. It is a relatively recent technology and is perceived as cost-effective, efficient, novel, eco-friendly, and solar-driven technology with good public acceptance. Phytoremediation is an area of active current research. New efficient metal hyperaccumulators are being explored for applications in phytoremediation and phytomining. Molecular tools are being used to better understand the mechanisms of metal uptake, translocation, sequestration and tolerance in plants. This review article comprehensively discusses the background, concepts and future trends in phytoremediation of heavy metals. Copyright © 2013 Elsevier Ltd. All rights reserved.

Modelling heavy metals build-up on urban road surfaces for effective stormwater reuse strategy implementation.

PubMed

Hong, Nian; Zhu, Panfeng; Liu, An

2017-12-01

Urban road stormwater is an alternative water resource to mitigate water shortage issues in the worldwide. Heavy metals deposited (build-up) on urban road surface can enter road stormwater runoff, undermining stormwater reuse safety. As heavy metal build-up loads perform high variabilities in terms of spatial distribution and is strongly influenced by surrounding land uses, it is essential to develop an approach to identify hot-spots where stormwater runoff could include high heavy metal concentrations and hence cannot be reused if it is not properly treated. This study developed a robust modelling approach to estimating heavy metal build-up loads on urban roads using land use fractions (representing percentages of land uses within a given area) by an artificial neural network (ANN) model technique. Based on the modelling results, a series of heavy metal load spatial distribution maps and a comprehensive ecological risk map were generated. These maps provided a visualization platform to identify priority areas where the stormwater can be safely reused. Additionally, these maps can be utilized as an urban land use planning tool in the context of effective stormwater reuse strategy implementation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Contamination of Polish national parks with heavy metals.

PubMed

Staszewski, Tomasz; Łukasik, Włodzimierz; Kubiesa, Piotr

2012-07-01

The paper presents results of screening analysis of all Polish national parks (23) contamination with Cd, Cu, Pb and Zn on the basis of a three-level characteristic of heavy metal presence in Norway spruce stands: accumulation on the needle surface, concentration of heavy metals in spruce needles and concentration of bioavailable heavy metals in the soil. Based on the obtained results, the classification of forest ecosystem hazard in national parks with heavy metals was made using synthetic indicators. It was found out that Babiogórski, Magurski, Ojcowski and Gorczański National Parks, located in the southern part of the country, were the most polluted with heavy metals. It is probably due to a higher industrial activity in this part of Poland and the transboundary transport of air pollutants. A little lower level of pollution was observed in Kampinoski National Park located in the middle of the country. The concentration of heavy metals found in needles from national parks does not seem to be harmful for the health status of the trees. Statistically significant correlation between all parameters, which was found for cadmium--the most mobile of the analysed elements--shows that this metal can be proposed as a marker to reflect present effect of industrial emission on forests.

Size distribution, characteristics and sources of heavy metals in haze episode in Beijing.

PubMed

Duan, Jingchun; Tan, Jihua; Hao, Jiming; Chai, Fahe

2014-01-01

Size segragated samples were collected during high polluted winter haze days in 2006 in Beijing, China. Twenty nine elements and 9 water soluble ions were determined. Heavy metals of Zn, Pb, Mn, Cu, As, Cr, Ni, V and Cd were deeply studied considering their toxic effect on human being. Among these heavy metals, the levels of Mn, As and Cd exceeded the reference values of National Ambient Air Quality Standard (GB3095-2012) and guidelines of World Health Organization. By estimation, high percentage of atmospheric heavy metals in PM2.5 indicates it is an effective way to control atmospheric heavy metals by PM2.5 controlling. Pb, Cd, and Zn show mostly in accumulation mode, V, Mn and Cu exist mostly in both coarse and accumulation modes, and Ni and Cr exist in all of the three modes. Considering the health effect, the breakthrough rates of atmospheric heavy metals into pulmonary alveoli are: Pb (62.1%) > As (58.1%) > Cd (57.9%) > Zn (57.7%) > Cu (55.8%) > Ni (53.5%) > Cr (52.2%) > Mn (49.2%) > V (43.5%). Positive matrix factorization method was applied for source apportionment of studied heavy metals combined with some marker elements and ions such as K, As, SO4(2-) etc., and four factors (dust, vehicle, aged and transportation, unknown) are identified and the size distribution contribution of them to atmospheric heavy metals are discussed.

Diversity of heavy metal resistant bacteria from Kalimas Surabaya: A phylogenetic taxonomy approach

NASA Astrophysics Data System (ADS)

Zulaika, Enny; Utomo, Andry Prio; Prima, Adisya; Alami, Nur Hidayatul; Kuswytasari, Nengah Dwianita; Shovitri, Maya; Sembiring, Langkah

2017-06-01

Bacterial resistance to heavy metal is a genetic and physiological adaptation to the environment which contaminated by heavy metal. Kalimas is an important river in Surabaya that is contaminated by some heavy metals and probably as a habitat for heavy metal resistance bacteria. Bacterial resistance to heavy metals are different for each species, and their diversity can be studied by phylogenetic taxonomy approach. Isolates screening was done using nutrient agar which contained 1 mg/L HgCl2, CdCl2 and K2Cr2O7. Bacterial viability were observed by nutrient broth which contained 10 mg/L HgCl2, 30 mg/L CdCl2 and 50 mg/L K2Cr2O7. Isolates that resistant to heavy metal and viable after exposure to heavy metal were identified using 16S rRNA gene marker by Polymerase Chain Reaction (PCR). Phylogenetic tree reconstruction was done by the neighbor-joining algorithm. Genetic assignment showed isolates that resist and viable after exposure of Hg, Cd and Cr are Bacillus S1, SS19 and DA11. Based on BLAST analysis from NCBI gene bank, 16S rRNA sequences, those isolates were similar with the member of Bacillus cereus. Depend on 16S rRNA nucleotide alignment by the neighbor-joining algorithm, Bacillus S1, SS19 and DA11 were belong to Bacillus cereus sensu-lato group.

Remediation of biochar on heavy metal polluted soils

NASA Astrophysics Data System (ADS)

Wang, Shuguang; Xu, Yan; Norbu, Namkha; Wang, Zhan

2018-01-01

Unreasonable mining and smelting of mineral resources, solid waste disposal, sewage irrigation, utilization of pesticides and fertilizers would result in a large number of heavy metal pollutants into the water and soil environment, causing serious damage to public health and ecological safety. In recent years, a majority of scholars tried to use biochar to absorb heavy metal pollutants, which has some advantages of extensive raw material sources, low-cost and high environmental stability. This paper reviewed the definition, properties of biochar, the mechanism of heavy metal sorption by biochar and some related problems and prospects, to provide some technical support for the application of biochar into heavy metal polluted soils.

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 metals in urban soils of East St. Louis, IL, Part I: Total concentration of heavy metals in soils.

PubMed

Kaminski, M D; Landsberger, S

2000-09-01

The city of East St. Louis, IL, has a history of abundant industrial activities including smelters of ferrous and non-ferrous metals, a coal-fired power plant, companies that produce organic and inorganic chemicals, and petroleum refineries. A protocol for soil analysis was developed to produce sufficient information on the extent of heavy metal contamination in East St. Louis soils. Soil cores representing every borough of East St. Louis were analyzed for heavy metals--As, Cd, Cu, Cr, Hg, Ni, Pb, Sb, Sn, and Zn. The topsoil contained heavy metal concentrations as high as 12.5 ppm Cd, 14,400 ppm Cu, ppm quantities of Hg, 1860 ppm Pb, 40 ppm Sb, 1130 ppm Sn, and 10,360 ppm Zn. Concentrations of Sb, Cu, and Cd were well correlated with Zn concentrations, suggesting a similar primary industrial source. In a sandy loam soil from a vacated rail depot near the bank of the Mississippi River, the metals were evenly distributed down to a 38-cm depth. The clay soils within a half-mile downwind of the Zn smelter and Cu products company contained elevated Cd (81 ppm), Cu (340 ppm), Pb (700 ppm), and Zn (6000 ppm) and displayed a systematic drop in concentration of these metals with depth. This study demonstrates the often high concentration of heavy metals heterogeneously distributed in the soil and provides baseline data for continuing studies of heavy metal soil leachability.

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.

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.

New trends in removing heavy metals from wastewater.

PubMed

Zhao, Meihua; Xu, Ying; Zhang, Chaosheng; Rong, Hongwei; Zeng, Guangming

2016-08-01

With the development of researches, the treatments of wastewater have reached a certain level. Whereas, heavy metals in wastewater cause special concern in recent times due to their recalcitrance and persistence in the environment. Therefore, it is important to get rid of the heavy metals in wastewater. The previous studies have provided many alternative processes in removing heavy metals from wastewater. This paper reviews the recent developments and various methods for the removal of heavy metals from wastewater. It also evaluates the advantages and limitations in application of these techniques. A particular focus is given to innovative removal processes including adsorption on abiological adsorbents, biosorption, and photocatalysis. Because these processes have leaded the new trends and attracted more and more researches in removing heavy metals from wastewater due to their high efficency, pluripotency and availability in a copious amount. In general, the applicability, characteristic of wastewater, cost-effectiveness, and plant simplicity are the key factors in selecting the most suitable method for the contaminated wastewater.

The remediation of heavy metals contaminated sediment.

PubMed

Peng, Jian-Feng; Song, Yong-Hui; Yuan, Peng; Cui, Xiao-Yu; Qiu, Guang-Lei

2009-01-30

Heavy metal contamination has become a worldwide problem through disturbing the normal functions of rivers and lakes. Sediment, as the largest storage and resources of heavy metal, plays a rather important role in metal transformations. This paper provides a review on the geochemical forms, affecting factors and remediation technologies of heavy metal in sediment. The in situ remediation of sediment aims at increasing the stabilization of some metals such as the mobile and the exchangeable fractions; whereas, the ex situ remediation mainly aims at removing those potentially mobile metals, such as the Mn-oxides and the organic matter (OM) fraction. The pH and OM can directly change metals distribution in sediment; however oxidation-reduction potential (ORP), mainly through changing the pH values, indirectly alters metals distribution. Mainly ascribed to their simple operation mode, low costs and fast remediation effects, in situ remediation technologies, especially being fit for slight pollution sediment, are applied widely. However, for avoiding metal secondary pollution from sediment release, ex situ remediation should be the hot point in future research.

Heavy metals in the cell nucleus - role in pathogenesis.

PubMed

Sas-Nowosielska, Hanna; Pawlas, Natalia

2015-01-01

People are exposed to heavy metals both in an occupational and natural environment. The most pronounced effects of heavy metals result from their interaction with cellular genetic material packed in form of chromatin. Heavy metals influence chromatin, mimicking and substituting natural microelements in various processes taking place in the cell, or interacting chemically with nuclear components: nucleic acids, proteins and lipids. This paper is a review of current knowledge on the effects of heavy metals on chromatin, exerted at the level of various nuclear components.

Multiple heavy metal removal using an entomopathogenic fungi Beauveria bassiana.

PubMed

Gola, Deepak; Dey, Priyadarshini; Bhattacharya, Arghya; Mishra, Abhishek; Malik, Anushree; Namburath, Maneesh; Ahammad, Shaikh Ziauddin

2016-10-01

Towards the development of a potential remediation technology for multiple heavy metals [Zn(II), Cu(II), Cd(II), Cr(VI) and Ni(II)] from contaminated water, present study examined the growth kinetics and heavy metal removal ability of Beauveria bassiana in individual and multi metals. The specific growth rate of B. bassiana varied from 0.025h(-1) to 0.039h(-1) in presence of individual/multi heavy metals. FTIR analysis indicated the involvement of different surface functional groups in biosorption of different metals, while cellular changes in fungus was reflected by various microscopic (SEM, AFM and TEM) analysis. TEM studies proved removal of heavy metals via sorption and accumulation processes, whereas AFM studies revealed increase in cell surface roughness in fungal cells exposed to heavy metals. Present study delivers first report on the mechanism of bioremediation of heavy metals when present individually as well as multi metal mixture by entomopathogenic fungi. Copyright © 2016 Elsevier Ltd. All rights reserved.

Analysis of heavy metals in road-deposited sediments.

PubMed

Herngren, Lars; Goonetilleke, Ashantha; Ayoko, Godwin A

2006-07-07

Road-deposited sediments were analysed for heavy metal concentrations at three different landuses (residential, industrial, commercial) in Queensland State, Australia. The sediments were collected using a domestic vacuum cleaner which was proven to be highly efficient in collecting sub-micron particles. Five particle sizes were analysed separately for eight heavy metal elements (Zn, Fe, Pb, Cd, Cu, Cr, Al and Mn). At all sites, the maximum concentration of the heavy metals occurred in the 0.45-75 microm particle size range, which conventional street cleaning services do not remove efficiently. Multicriteria decision making methods (MCDM), PROMETHEE and GAIA, were employed in the data analysis. PROMETHEE, a non-parametric ranking analysis procedure, was used to rank the metal contents of the sediments sampled at each site. The most polluted site and particle size range were the industrial site and the 0.45-75 microm range, respectively. Although the industrial site displayed the highest metal concentrations, the highest heavy metal loading coincided with the highest sediment load, which occurred at the commercial site. GAIA, a special form of principal component analysis, was applied to determine correlations between the heavy metals and particle size ranges and also to assess possible correlation with total organic carbon (TOC). The GAIA-planes revealed that irrespective of the site, most of the heavy metals are adsorbed to sediments below 150 microm. A weak correlation was found between Zn, Mn and TOC at the commercial site. This could lead to higher bioavailability of these metals through complexation reactions with the organic species in the sediments.

Multiscale correlations of iron phases and heavy metals in technogenic magnetic particles from contaminated soils.

PubMed

Yu, Xiuling; Lu, Shenggao

2016-12-01

Technogenic magnetic particles (TMPs) are carriers of heavy metals and organic contaminants, which derived from anthropogenic activities. However, little information on the relationship between heavy metals and TMP carrier phases at the micrometer scale is available. This study determined the distribution and association of heavy metals and magnetic phases in TMPs in three contaminated soils at the micrometer scale using micro-X-ray fluorescence (μ-XRF) and micro-X-ray absorption near-edge structure (μ-XANES) spectroscopy. Multiscale correlations of heavy metals in TMPs were elucidated using wavelet transform analysis. μ-XRF mapping showed that Fe was enriched and closely correlated with Co, Cr, and Pb in TMPs from steel industrial areas. Fluorescence mapping and wavelet analysis showed that ferroalloy was a major magnetic signature and heavy metal carrier in TMPs, because most heavy metals were highly associated with ferroalloy at all size scales. Multiscale analysis revealed that heavy metals in the TMPs were from multiple sources. Iron K-edge μ-XANES spectra revealed that metallic iron, ferroalloy, and magnetite were the main iron magnetic phases in the TMPs. The relative percentage of these magnetic phases depended on their emission sources. Heatmap analysis revealed that Co, Pb, Cu, Cr, and Ni were mainly derived from ferroalloy particles, while As was derived from both ferroalloy and metallic iron phases. Our results indicated the scale-dependent correlations of magnetic phases and heavy metals in TMPs. The combination of synchrotron based X-ray microprobe techniques and multiscale analysis provides a powerful tool for identifying the magnetic phases from different sources and quantifying the association of iron phases and heavy metals at micrometer scale. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

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.

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.

[Heavy Metals Accmultio in the Caofeidian Reclamation Soils: Indicated by Soil Magnetic Susceptibility].

PubMed

Xue, Yong; Zhou, Qian; Li, Yuan; Zhang, Hai-bo; Hu, Xue-feng; Luo, Yong-ming

2016-04-15

The environmental magnetism method has been widely applied to identify soil heavy metal pollution, which is characterized by simplicity, efficiency, non-destructivity and sensitivity. The present study used magnetic susceptibility to assess the accumulation of heavy metals in soils of the Caofeidian industrial zone which is a typical reclamation area in northern China. The study area was divided into three sub-zones based on the function, including industrial zone, living zone, natural tidal flat and wetland. A total of 35 topsoil samples (0-10 cm) and 3 soil profiles were collected from the three sub-zones. Magnetic susceptibility (X(lf)), iron oxide (Fe2O3) contents and heavy metals contents (Cr, Ni, Cu, Zn, As, Pb, Mn and V) of the samples were analyzed. The results showed that X(lf) values and heavy metals contents exhibited higher spatial variability in the top soil of the industrial zone, indicating the severe impacts of industrial activities. In the soil profiles of the industrial and living zones, all heavy metals were enriched to different degrees in the upper layer (0-20 cm). However, there was no significant change of heavy metal contents in the soil profiles of tidal flat which was far from the industrial area. The X(lf) value was significantly (P < 0.01) positively correlated with the contents of Fe2O3, Ni, Cu, As and V in the industrial top soil. This indicated that X(lf) could be used as an indicator for heavy metal accumulation in the industrial zone. However, the X(lf) value was not suitable to be an indicator to show the heavy metal accumulation in the soils of living zone and natural tidal flat. This might be associated with the different sources of magnetic materials among the different sub-zones and the special characteristics of the soils in the tidal flat and wetland.

Pathways of heavy metals contamination and associated human health risk in Ajay River basin, India.

PubMed

Singh, Umesh Kumar; Kumar, Balwant

2017-05-01

The sources of heavy metals and their loads in the Ajay River were investigated based on the seasonal and spatial variations. To identify variation and pathways of heavy metals, seventy-six water samples were estimated for 2 years at nineteen sampling sites. The multifaceted data were applied to evaluate statistical relation between variables and arithmetic calculation of the indices. Fickling plot suggested that the acidic pollutants do not affect the water quality because all samples lie within the neutral pH range. Further, OC showed significant relation with Fe, Mn, Ni and Co. Compositional analysis identified weathering of rocks, mobility of soil and sediment, atmospheric deposition and numerous anthropogenic inputs as major sources of heavy metals. The mean values of heavy metal pollution index (HPI) and pollution index (PI) were found above the critical index and strong loadings respectively due to higher values of Cd, Pb and Fe. Similarly, assessment of human risk revealed that the high load of Cd, Pb and Fe in water body could harm the population. Majority of the samples showed high concentration of heavy metals as compared to regulatory standard and background values, which suggests that the water is highly contaminated through numerous geogenic and anthropogenic sources. Copyright © 2017 Elsevier Ltd. 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

Removal of heavy metals from waste streams

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

Spence, M.D.; Kozaruk, J.M.; Melvin, M.

1988-07-19

A method for removing heavy metals from effluent water is described comprising performing sequentially the following steps: (a) adding from 7-333 ppm of an anionic surfactant to the effluent water to provide coagulatable heavy metal ion; (b) adjusting the effluent water pH to within the range of 8 to 10, (c) providing from 10-200 ppm of a cationic coagulant to coagulate the heavy metal ion, (d) providing from 0.3 to 5.0 ppm of a polymeric flocculant whereby a heavy metal containing floc is formed for removal from the effluent water, and, (e) then removing the floc from the effluent water,more » wherein the anionic surfactant is sodium lauryl ether sulfate. The cationic coagulant is selected from the group consisting of diallyl dimethylammonium chloride polymer, epichlorohydrin dimethylamine polymer, ethylene amine polymer, polyaluminum chloride, and alum; and the flocculant is an acrylamide/sodium acrylate copolymer having an RSV greater than 23.« less

Community Heavy Metal Exposure, San Francisco, California

NASA Astrophysics Data System (ADS)

Chavez, A.; Devine, M.; Ho, T.; Zapata, I.; Bissell, M.; Neiss, J.

2008-12-01

Heavy metals are natural elements that generally occur in minute concentrations in the earth's crust. While some of these elements, in small quantities, are vital to life, most are harmful in larger doses. Various industrial and agricultural processes can result in dangerously high concentrations of heavy metals in our environment. Consequently, humans can be exposed to unsafe levels of these elements via the air we breathe, the water and food we consume, and the many products we use. During a two week study we collected numerous samples of sediments, water, food, and household items from around the San Francisco Bay Area that represent industrial, agricultural, and urban/residential settings. We analyzed these samples for Mercury (Hg), Lead (Pb), and Arsenic (As). Our goal was to examine the extent of our exposure to heavy metals in our daily lives. We discovered that many of the common foods and materials in our lives have become contaminated with unhealthy concentrations of these metals. Of our food samples, many exceeded the EPA's Maximum Contaminant Levels (MCL) set for each metal. Meats (fish, chicken, and beef) had higher amounts of each metal than did non-meat items. Heavy metals were also prevalent in varying concentrations in the environment. While many of our samples exceeded the EPA's Sediment Screening Level (SSL) for As, only two other samples surpassed the SSL set for Pb, and zero of our samples exceeded the SSL for Hg. Because of the serious health effects that can result from over-exposure to heavy metals, the information obtained in this study should be used to influence our future dietary and recreational habits.

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.

[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.

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 Metals in the Environment-Historical Trends

NASA Astrophysics Data System (ADS)

Callender, E.

2003-12-01

These six metals, commonly classified as heavy metals, are a subset of a larger group of trace elements that occur in low concentration in the Earth's crust. These heavy metals were mined extensively for use in the twentieth century Industrial Society. Nriagu (1988a) estimated that between 0.5 (Cd) and 310 (Cu) million metric tons of these metals were mined and ultimately deposited in the biosphere. In many instances, the inputs of these metals from anthropogenic sources exceed the contributions from natural sources (weathering, volcanic eruptions, forest fires) by several times ( Adriano, 1986). In this chapter, heavy metals (elements having densities greater than 5) and trace elements (elements present in the lithosphere in concentrations less than 0.1%) are considered synonymous.It has been observed in the past that the rate of emission of these trace metals into the atmosphere is low due to their low volatility. However, with the advent of large-scale metal mining and smelting as well as fossil-fuel combustion in the twentieth century, the emission rate of these metals has increased dramatically. As most of these emissions are released into the atmosphere where the mammals live and breathe, we see a great increase in the occurrence of health problems such as lead (Pb) poisoning, cadmium (Cd) Itai-itai disease, chromium (Cr), and nickel (Ni) carcinogenesis.In this chapter, the author has attempted to present a synopsis of the importance of these metals in the hydrocycle, their natural and anthropogenic emissions into the environment, their prevalent geochemical form incorporated into lacustrine sediments, and their time-trend distributions in watersheds that have been impacted by urbanization, mining and smelting, and other anthropogenic activities. These time trends are reconstructed from major-minor-trace-element distributions in age-dated sediment cores, mainly from reservoirs where the mass sedimentation rates (MSRs) are orders of magnitude greater than

Heavy metals and living systems: An overview

PubMed Central

Singh, Reena; Gautam, Neetu; Mishra, Anurag; Gupta, Rajiv

2011-01-01

Heavy metals are natural constituents of the earth's crust, but indiscriminate human activities have drastically altered their geochemical cycles and biochemical balance. This results in accumulation of metals in plant parts having secondary metabolites, which is responsible for a particular pharmacological activity. Prolonged exposure to heavy metals such as cadmium, copper, lead, nickel, and zinc can cause deleterious health effects in humans. Molecular understanding of plant metal accumulation has numerous biotechnological implications also, the long term effects of which might not be yet known. PMID:21713085

Tracing heavy metals in 'swine manure - maggot - chicken' production chain.

PubMed

Wang, Wanqiang; Zhang, Wenjuan; Wang, Xiaoping; Lei, Chaoliang; Tang, Rui; Zhang, Feng; Yang, Qizhi; Zhu, Fen

2017-08-21

With the development of large-scale livestock farming, manure pollution has drawn much attention. Conversion by insects is a rapid and cost-effective new method for manure management. Swine manure conversion with maggots (Musca domestica larvae) has developed, and the harvested maggots are often used as animal feed. However, the flow of heavy metals from manure to downstream processes cannot be ignored, and therefore, heavy metal content was measured in untreated raw manure, maggot-treated manure, harvested maggots and maggot-eating chickens (chest muscle and liver) to evaluate potential heavy metal risks. The levels of zinc, copper, chromium, selenium, cadmium and lead had significant differences between untreated raw manure and maggot-treated manure. The concentrations of all detected heavy metals, except for cadmium and selenium, in maggots met the limits established by the feed or feed additive standards of many countries. The bioaccumulation factor (BAF) of heavy metals decreased with the increase of the maggot instar, indicating that heavy metals were discharged from the bodies of maggots with the growth of maggots. Also, the contents of overall heavy metals in chickens fed harvested maggots met the standards for food. In conclusion, regarding heavy metals, it is eco-safe to use maggots in manure management.

Heavy Metal Music and Adolescent Suicidal Risk.

ERIC Educational Resources Information Center

Lacourse, Eric; Claes, Michel; Villeneuve, Martine

2001-01-01

Studied differentiating characteristics of youth who prefer heavy metal music, worship music, and use music for vicarious release. Data for 275 secondary school students suggest that heavy metal music preference and worshipping is not related to suicidal risk when controlling for other suicide factors. Discusses findings in the context of…

Evaluation of remediation process with plant-derived biosurfactant for recovery of heavy metals from contaminated soils.

PubMed

Hong, Kyung-Jin; Tokunaga, Shuzo; Kajiuchi, Toshio

2002-10-01

A washing process was studied to evaluate the efficiency of saponin on remediating heavy metal contaminated soils. Three different types of soils (Andosol: soil A, Cambisol: soil B, Regosol: soil C) were washed with saponin in batch experiments. Utilization of saponin was effective for removal of heavy metals from soils, attaining 90-100% of Cd and 85-98% of Zn extractions. The fractionations of heavy metals removed by saponin were identified using the sequential extraction. Saponin was effective in removing the exchangeable and carbonated fractions of heavy metals from soils. In recovery procedures, the pH of soil leachates was increased to about 10.7, leading to separate heavy metals as hydroxide precipitates and saponin solute. In addition recycle of used saponin is considered to be effective for the subsequent utilization. The limits of Japanese leaching test were met for all of the soil residues after saponin treatment. As a whole, this study shows that saponin can be used as a cleaning agent for remediation of heavy metal contaminated soils.

Heavy metal displacement in chelate-irrigated soil during phytoremediation

NASA Astrophysics Data System (ADS)

Madrid, F.; Liphadzi, M. S.; Kirkham, M. B.

2003-03-01

Heavy metals in wastewater sewage sludge (biosolids), applied to land, contaminate soils. 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 and without roots following solubilization with chelates. The objective of this work was to determine the mobility of heavy metals in biosolids applied to the surface of soil columns (76 cm long; 17 cm diam.) with or without plants (barley; Hordeum vulgare L.). Three weeks after barley was planted, all columns were irrigated with the disodium salt of the chelating agent, EDTA (ethylenediamine tetraacetic acid) (0.5 g/kg soil). Drainage water, soil, and plants were analyzed for heavy metals (Cd, Cu, Fe, Mn, Ni, Pb, Zn). Total concentrations of the heavy metals in all columns at the end of the experiment generally were lower in the top 30 cm of soil with EDTA than without EDTA. The chelate increased concentrations of heavy metals in shoots. With or without plants, the EDTA mobilized Cd, Fe, Mn, Ni, Pb, and Zn, which leached to drainage water. Drainage water from columns without EDTA had concentrations of these heavy metals below detection limits. Only Cu did not leach in the presence of EDTA. Even though roots retarded the movement of Cd, Fe, Mn, Ni, Pb, and Zn through the EDTA-treated soil from 1 d (Cd) to 5 d (Fe), the drainage water from columns with EDTA had concentrations of Cd, Fe, Mn, and Pb that exceeded drinking water standards by 1.3, 500, 620, and 8.6 times, respectively. Because the chelate rendered Cd, Fe, Mn, Ni, Pb, and Zn mobile, it is suggested that the theory for leaching of soluble salts, put forward by Nielsen and associates in 1965, could be applied to control movement of the heavy metals for maximum uptake during chelate-assisted phytoremediation.

Bioremediation of heavy metal-contaminated effluent using optimized activated sludge bacteria

NASA Astrophysics Data System (ADS)

Bestawy, Ebtesam El.; Helmy, Shacker; Hussien, Hany; Fahmy, Mohamed; Amer, Ranya

2013-03-01

Removal of heavy metals from contaminated domestic-industrial effluent using eight resistant indigenous bacteria isolated from acclimatized activated sludge was investigated. Molecular identification using 16S rDNA amplification revealed that all strains were Gram-negative among which two were resistant to each of copper, cadmium and cobalt while one was resistant to each of chromium and the heavy metal mixture. They were identified as Enterobacter sp. (Cu1), Enterobacter sp. (Cu2), Stenotrophomonas sp. (Cd1), Providencia sp. (Cd2), Chryseobacterium sp. (Co1), Comamonas sp. (Co2), Ochrobactrum sp. (Cr) and Delftia sp. (M1) according to their resistance pattern. Strains Cu1, Cd1, Co2 and Cr were able to resist 275 mg Cu/l, 320 mg Cd/l, 140 mg Co/l and 29 mg Cr/l respectively. The four resistant strains were used as a mixture to remove heavy metals (elevated concentrations) and reduce the organic load of wastewater effluent. Results revealed that using the proposed activated sludge with the resistant bacterial mixture was more efficient for heavy metal removal compared to the activated sludge alone. It is therefore recommended that the proposed activated sludge system augmented with the acclimatized strains is the best choice to ensure high treatment efficiency and performance under metal stresses especially when industrial effluents are involved.

Assessment of spatial distribution of soil heavy metals using ANN-GA, MSLR and satellite imagery.

PubMed

Naderi, Arman; Delavar, Mohammad Amir; Kaboudin, Babak; Askari, Mohammad Sadegh

2017-05-01

This study aims to assess and compare heavy metal distribution models developed using stepwise multiple linear regression (MSLR) and neural network-genetic algorithm model (ANN-GA) based on satellite imagery. The source identification of heavy metals was also explored using local Moran index. Soil samples (n = 300) were collected based on a grid and pH, organic matter, clay, iron oxide contents cadmium (Cd), lead (Pb) and zinc (Zn) concentrations were determined for each sample. Visible/near-infrared reflectance (VNIR) within the electromagnetic ranges of satellite imagery was applied to estimate heavy metal concentrations in the soil using MSLR and ANN-GA models. The models were evaluated and ANN-GA model demonstrated higher accuracy, and the autocorrelation results showed higher significant clusters of heavy metals around the industrial zone. The higher concentration of Cd, Pb and Zn was noted under industrial lands and irrigation farming in comparison to barren and dryland farming. Accumulation of industrial wastes in roads and streams was identified as main sources of pollution, and the concentration of soil heavy metals was reduced by increasing the distance from these sources. In comparison to MLSR, ANN-GA provided a more accurate indirect assessment of heavy metal concentrations in highly polluted soils. The clustering analysis provided reliable information about the spatial distribution of soil heavy metals and their sources.

Microbes in Heavy Metal Remediation: A Review on Current Trends and Patents.

PubMed

Mishra, Geetesh Kumar

2017-01-01

Heavy metal pollution in the environmental samples like soil, water and runoff water is a worldwide problem. Such contamination of environmental matrices by the heavy metals accumulates due to various activities involving human driven sources and industries, although agriculture and sewage disposal are the largest source for the heavy metal contamination. Disposal of heavy metals or waste products containing heavy metals in the environment postures a trivial threat to public safety and health. Heavy metals are persistence and they can also cause biomagnifications and accumulate in food chain. Microbial bioremediation of heavy metal is emerging as an effective technique. Microbial bioremediation is a highly efficient environmental friendly procedure which also reduces the cost of cleanup process associated with heavy metal contamination. New methods for removal of heavy metals from the environmental samples are under development and most recent advancements have been made in exploring the knowledge of metal-microbes interactions and its use for heavy metal remediation. This review paper will focus on the microbial bioremediation process and highlight some of the newly developed patented methods for microbial bioremediation of the heavy metals from the environmental samples using microbial populations. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Influence of heavy metal stress on antioxidant status and DNA damage in Urtica dioica.

PubMed

Gjorgieva, Darinka; Kadifkova Panovska, Tatjana; Ruskovska, Tatjana; Bačeva, Katerina; Stafilov, Trajče

2013-01-01

Heavy metals have the potential to interact and induce several stress responses in the plants; thus, effects of heavy metal stress on DNA damages and total antioxidants level in Urtica dioica leaves and stems were investigated. The samples are sampled from areas with different metal exposition. Metal content was analyzed by Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), for total antioxidants level assessment the Ferric-Reducing Antioxidant Power (FRAP) assay was used, and genomic DNA isolation from frozen plant samples was performed to obtain DNA fingerprints of investigated plant. It was found that heavy metal contents in stems generally changed synchronously with those in leaves of the plant, and extraneous metals led to imbalance of mineral nutrient elements. DNA damages were investigated by Random Amplified Polymorphic DNA (RAPD) technique, and the results demonstrated that the samples exposed to metals yielded a large number of new fragments (total 12) in comparison with the control sample. This study showed that DNA stability is highly affected by metal pollution which was identified by RAPD markers. Results suggested that heavy metal stress influences antioxidant status and also induces DNA damages in U. dioica which may help to understand the mechanisms of metals genotoxicity.

Influence of Heavy Metal Stress on Antioxidant Status and DNA Damage in Urtica dioica

PubMed Central

Kadifkova Panovska, Tatjana; Bačeva, Katerina; Stafilov, Trajče

2013-01-01

Heavy metals have the potential to interact and induce several stress responses in the plants; thus, effects of heavy metal stress on DNA damages and total antioxidants level in Urtica dioica leaves and stems were investigated. The samples are sampled from areas with different metal exposition. Metal content was analyzed by Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), for total antioxidants level assessment the Ferric-Reducing Antioxidant Power (FRAP) assay was used, and genomic DNA isolation from frozen plant samples was performed to obtain DNA fingerprints of investigated plant. It was found that heavy metal contents in stems generally changed synchronously with those in leaves of the plant, and extraneous metals led to imbalance of mineral nutrient elements. DNA damages were investigated by Random Amplified Polymorphic DNA (RAPD) technique, and the results demonstrated that the samples exposed to metals yielded a large number of new fragments (total 12) in comparison with the control sample. This study showed that DNA stability is highly affected by metal pollution which was identified by RAPD markers. Results suggested that heavy metal stress influences antioxidant status and also induces DNA damages in U. dioica which may help to understand the mechanisms of metals genotoxicity. PMID:23862140

[Beijing common green tree leaves' accumulation capacity for heavy metals].

PubMed

Li, Shao-Ning; Kong, Ling-Wei; Lu, Shao-Wei; Chen, Bo; Gao, Chen; Shi, Yuan

2014-05-01

Seasonal variation of heavy metal contents in leaves and their relationships with soil heavy metal pollution levels were studied through measuring and analyzing the leaves of the common tree species in Beijing and soil heavy metal contents, to detect heavy metal accumulation ability of plant leaves. The results showed that: (1) the contents of Cu, Pb, Zn in plant leaves first decreased and then increased, again declined with changing the seasons (from spring to winter). Cr concentration showed the trend of first increase and then decrease from spring to winter, and the highest in the autumn; the accumulation capacities of Cu for Babylonica and Japonica were higher in the spring, summer and autumn, while Tabuliformis was in winter; the higher accumulation capacities for Cr, Pb were Japonica and Platycladus, and in winter were Platycladus and Bungeana; the higher accumulation capacities for Zn were Babylonica and Bungeana, while Platycladus in winter; (2) the pollution degree of four kinds of heavy metals (Cu, Cr, Pb, Zn) from downtown to suburbs showed that: Jingshan (C =2.48, C is contamination factor) > Olympic (C = 1.27) > Songshan (C = 1.20) > Shuiguan (C = 1. 18); (3) the heavy metals concentration of same plant leaves in the water of the Great Wall changed larger, but those in the other three areas showed that: Jingshan > Olympic > Songshan; the ability of same species leaf to absorb different sorts of heavy metals showed that: Zn >Cu >Pb >Cr; the difference between Zn content and Cr content was significant (P <0.01); (4) the relationship between heavy metal content in plant leaves and soil heavy metal pollution levels presented a quadratic polynomial relation; the significant correlation was found between other three heavy metal contents of plant samples and soil samples, but they were not the case for the Cu, and the correlation coefficients were above 0. 9.

A review of heavy metals in indoor dust and its human health-risk implications.

PubMed

Tan, Sock Yin; Praveena, Sarva Mangala; Abidin, Emilia Zainal; Cheema, Manraj Singh

2016-12-01

Indoor dust acts as a media for heavy metal deposition. Past studies have shown that heavy metal concentration in indoor dust is affected by local human activities and atmospheric transport can have harmful effects on human health. Additionally, children are more sensitive to heavy metals due to their hand-to-mouth behaviour and rapid body development. However, limited information on health risks were found in past dust studies as these studies aimed to identify heavy metal concentrations and sources of indoor dust. The objective of this review is to discuss heavy metal concentration and sources influencing its concentration in indoor dust. Accordingly, high lead (Pb) concentration (639.10 μg/g) has been reported in heavy traffic areas. In addition, this review paper aims to estimate the health risk to children from heavy metals in indoor dust via multiple exposure pathways using the health-risk assessment (HRA). Urban areas and industrial sites have revealed high heavy metal concentration in comparison to rural areas. Hazard index (HI) values found in arsenic (As), chromium (Cr) and Pb were 21.30, 1.10 and 2.40, respectively, indicate that non-carcinogenic elements are found in children. Furthermore, most of the past studies have found that carcinogenic risks for As, cadmium (Cd), Cr and Pb were below the acceptable total lifetime cancer risk (TLCR) range (1×10-6-1×10-4). The results of health risk assessment in this review show that carcinogenic risk exists among children. Hence, this proves that future studies need to focus on children's carcinogenic risk in indoor dust studies in order to find out the sources of heavy metals in indoor dust. This review highlights the importance of having the HRA application using bioavailable heavy metal concentration as it provides more accurate health-risk estimation. Moreover, this review is also useful as a reference for policy decision making in protecting children's health.

Magnetic evidence for heavy metal pollution of topsoil in Shanghai, China

NASA Astrophysics Data System (ADS)

Wang, Guan; Liu, Yuan; Chen, Jiao; Ren, Feifan; Chen, Yuying; Ye, Fangzhou; Zhang, Weiguo

2018-03-01

This study presents the results obtained from magnetic susceptibility and heavy metal (Cu, Zn, Pb, and Cr) concentration measurements of soil profiles collected from arable land and urban parks in Baoshan District, an industrial district of Shanghai, China. The study focuses on the investigation of vertical variations in magnetic susceptibilities and heavy metal concentrations and on correlations between magnetic susceptibilities and heavy metal concentrations in soil profiles. The results demonstrate that magnetic enhancement in the surface layer of the soil profile is associated with increased heavy metal pollution. The enrichment factors (EF) and the Tomlinson Pollution Load Index (PLI-EF) are calculated for estimating the level of heavy metal pollution of soil profiles in the study. The significant positive correlations between heavy metal contents, enrichment factors (EF), Tomlinson pollution load index (PLI-CF), modified Tomlinson pollution load index (PLI-EF), and magnetic susceptibility (c) indicate that much of the heavy metal contamination in the study area is linked to combustion derived particulate emissions. The results confirm that the combined magnetic measurement and heavy metal concentration analysis could provide useful information for soil monitoring in urban environments. However, the use of magnetic technique to locate the heavy metal pollution boundary in the soil profile of this studied area should be confirmed by further geochemical analysis.

Case report: heavy metal burden presenting as Bartter syndrome.

PubMed

Crinnion, Walter J; Tran, Jessica Q

2010-12-01

Maternal transfer of heavy metals during fetal development or lactation possibly contributed to the clinical manifestations of Bartter syndrome and developmental delay in the offspring. An 11-month-old child diagnosed with Bartter syndrome and failure to thrive was treated concurrently for elevated metal burden while he was undergoing standard medical interventions. Treatment with body-weight doses of meso-2,3-dimercaptosuccinic acid (DMSA) reduced the body burden of lead, beryllium, copper, mercury, and cadmium at the three- and sixth-month follow-up tests. During the course of the six-month treatment, the patient gained 2.4 kg (5.2 lb) and grew approximately 9.5 cm (3.75 in). His weight shifted from significantly below the 5th percentile in weight to within the 5th percentile, and from below the 5th to within the 10th percentile for length. The child's acquisition of lead, beryllium, and copper correspond to his mother's history of stained glass assembly and occurred during fetal development or lactation, since there were no other identifiable sources that could have contributed to the heavy metal burden. Tests for known genetic mutations leading to Bartter syndrome were all negative. This case report highlights the potential benefit of DMSA for treatment of heavy metal body burden in infants who present with Bartter syndrome.

Heavy metal-binding proteins from metal-stimulated bacteria as a novel adsorbent for metal removal technology.

PubMed

Sano, D; Myojo, K; Omura, T

2006-01-01

Water pollution with toxic heavy metals is of growing concern because heavy metals could bring about serious problems for not only ecosystems in the water environment but also human health. Some metal removal technologies have been in practical use, but much energy and troublesome treatments for chemical wastes are required to operate these conventional technologies. In this study, heavy metal-binding proteins (HMBPs) were obtained from metal-stimulated activated sludge culture with affinity chromatography using copper ion as a ligand. Two-dimensional electrophoresis revealed that a number of proteins in activated sludge culture were recovered as HMBPs for copper ion. N-termini of five HMBPs were determined, and two of them were found to be newly discovered proteins for which no amino acid sequences in protein databases were retrieved at more than 80% identities. Metal-coordinating amino acids occupied 38% of residues in one of the N-terminal sequences of the newly discovered HMBPs. Since these HMBPs were expected to be stable under conditions of water and wastewater treatments, it would be possible to utilize HMBPs as novel adsorbents for heavy metal removal if mass volume of HMBPs can be obtained with protein cloning techniques.

Investigation of heavy metals release from sediment with bioturbation/bioirrigation.

PubMed

He, Yi; Men, Bin; Yang, Xiaofang; Li, Yaxuan; Xu, Hui; Wang, Dongsheng

2017-10-01

Bioturbation/bioirrigation can affect the remobilization of metals from sediments. In this study, experiments were performed to examine the effect of bioturbation/bioirrigation by different organisms on cadmium (Cd), copper (Cu), zinc (Zn) and lead (Pb) releasing from the spiked sediment. The diffusive gradient in thin films technique (DGT) revealed that at the end of exposure time, the labile heavy metals concentrations in the pore water for all metal and organisms combinations except Cu and chironomid larvae were much lower than that in the control group. However, the concentrations of heavy metals detected by the DGT were virtually indistinguishable among the treatments with tubificid, chironomid larvae and loach. The correlation analysis of heavy metals with iron (Fe) and manganese (Mn) suggested that Cd, Zn and Pb were most likely bound as Fe-Mn oxidation form in the pore water, but Cu was in other forms. After 28 d of exposure, bioturbation/bioirrigation produced a significant release of particulate heavy metals into the overlying water, especially in the treatment with loach. The bioturbation/bioirrigation impact on the Pb remobilization was less than the other three heavy metals. The effects of bioturbaiton/bioirrigation on the heavy metals remobilization in the sediment were complex that with studying the heavy metals remobilization in the sediment and water interface, the biological indicators should be recommended. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pollution assessment and source apportionment of heavy metals in contaminated site soils

NASA Astrophysics Data System (ADS)

Zheng, Hongbo; Ma, Yan

2018-03-01

Pollution characteristics of heavy metals in soil were analyzed with a typical contaminated site as the case area. The pollution degree of the element was evaluated by indexes of geoaccumulation (Igeo). The potential ecological risk of heavy metals was assessed with potential ecological risk index model. Principal component analysis (PCA) model was simultaneously carried out to identify the main sources of heavy metals in topsoils. The results indicated that: 1. Mean values of 11 kinds of metals in topsoils were greater than respective soil background values, following the order: Zn>Pb>V>Cr>Cu>Ni>Co>As>Sb>Cd>Hg. Heavy metals with a certain accumulation in the research area were significantly affected by external factors. 2. Igeo results showed that Cd and Zn reached strongly polluted degree, while Pb with moderately to strongly polluted, Sb and Hg with moderately polluted, Cu, Co, Ni and Cr with unpolluted to moderately polluted, V and As with un-polluted. 3. Potential ecological risk assessment showed the degree of ecological risk with Cd at very high risk, Hg at high risk, Pb at moderate risk and others at low risk. The comprehensive risk of all the metals was very high. 4. PCA got three main sources with contributions, including industrial activities (44.18%), traffic and burning dust (26.68%) and soil parent materials (12.20%).

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.

Heavy metals phytoremediation potential of Hevea brasiliensis in Bentong, Malaysia

NASA Astrophysics Data System (ADS)

Yusof, Muhammad Jefri Mohd; Latif, Mohd Talip; Yusoff, Siti Fairus Mohd

2018-04-01

Biomonitoring uses living organisms to assess environmental quality and being preferred over conventional methods that use fully or semi-automatic gauges for its lower cost and practicality. Recently, higher plants are widely used for biomonitoring purposes by means of their species identification simplicity, larger availability of biological substantial, and easy to sample. In this study, samples of Hevea brasiliensis (i.e leaves, barks, and latex as well as surrounding soils) from outskirts of Pelangai, Bentong were tested for heavy metals by using inductively coupled plasma optical emission spectroscopy (ICP-OES). Enrichment factor of soils indicated that some metals (B, Ca, Cu, Mn, Pb, Zn, As and Na) were anthropogenic which most likely originated from traffic emissions. In addition, leaves trapped the most heavy metals compared to barks and latex. The accumulation of pollutants in those samples has identified biomonitoring abilities of Hevea brasiliensis.

Multivariate statistical analysis of heavy metal concentration in soils of Yelagiri Hills, Tamilnadu, India--spectroscopical approach.

PubMed

Chandrasekaran, A; Ravisankar, R; Harikrishnan, N; Satapathy, K K; Prasad, M V R; Kanagasabapathy, K V

2015-02-25

Anthropogenic activities increase the accumulation of heavy metals in the soil environment. Soil pollution significantly reduces environmental quality and affects the human health. In the present study soil samples were collected at different locations of Yelagiri Hills, Tamilnadu, India for heavy metal analysis. The samples were analyzed for twelve selected heavy metals (Mg, Al, K, Ca, Ti, Fe, V, Cr, Mn, Co, Ni and Zn) using energy dispersive X-ray fluorescence (EDXRF) spectroscopy. Heavy metals concentration in soil were investigated using enrichment factor (EF), geo-accumulation index (Igeo), contamination factor (CF) and pollution load index (PLI) to determine metal accumulation, distribution and its pollution status. Heavy metal toxicity risk was assessed using soil quality guidelines (SQGs) given by target and intervention values of Dutch soil standards. The concentration of Ni, Co, Zn, Cr, Mn, Fe, Ti, K, Al, Mg were mainly controlled by natural sources. Multivariate statistical methods such as correlation matrix, principal component analysis and cluster analysis were applied for the identification of heavy metal sources (anthropogenic/natural origin). Geo-statistical methods such as kirging identified hot spots of metal contamination in road areas influenced mainly by presence of natural rocks. Copyright © 2014 Elsevier B.V. All rights reserved.

Sources, spatial variation, and speciation of heavy metals in sediments of the Tamagawa River in Central Japan.

PubMed

Shikazono, N; Tatewaki, K; Mohiuddin, K M; Nakano, T; Zakir, H M

2012-01-01

Sediments of the Tamagawa River in central Japan were studied to explain the spatial variation, to identify the sources of heavy metals, and to evaluate the anthropogenic influence on these pollutants in the river. Sediment samples were collected from 20 sites along the river (five upstream, four midstream, and 11 downstream). Heavy metal concentrations, viz. chromium, nickel, copper, zinc, lead, cadmium, and molybdenum, in the samples were measured using inductively coupled plasma-mass spectroscopy. The chemical speciations of heavy metals in the sediments were identified by the widely used five-step Hall method. Lead isotopes were analyzed to identify what portion is contributed by anthropogenic sources. The total heavy metal concentrations were compared with global averages for continental crust (shale) and average values for Japanese river sediments. The mean heavy metal concentrations were higher in downstream sediments than in upstream and midstream samples, and the concentrations in the silt samples were higher than those in the sand samples. Speciation results demonstrate that, for chromium and nickel, the residual fractions were dominant. These findings imply that the influence of anthropogenic chromium and nickel contamination is negligible, while copper, zinc, and lead were mostly extracted in the non-residual fraction (metals in adsorbed/exchangeable/carbonate forms or bound to amorphous Fe oxyhydroxides, crystalline Fe oxides, or organic matter), indicating that these elements have high chemical mobility. The proportion of lead (Pb) isotopes in the downstream silt samples indicates that Pb accumulation is primarily derived from anthropogenic sources.

Biosorption of heavy metals and uranium from dilute solutions

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

Schneider, I.A.H.; Misra, M.; Smith, R.W.

1995-08-01

Eichhornia crassipes approaches being a scourge in many parts of the world, choking waterways and hindering transport upon them. At the same time it is known to readily abstract heavy metal ions from water and, thus, aids in the removal of heavy metals found in such waters. This paper considers the possibility of using specific parts of the plant as an inexpensive adsorbent for the removal of heavy metals from contaminated chemical and mining industry waste waters. In particular the root of the plant was found to be an excellent accumulator of heavy metal ions including uranium from solution. Itmore » is also suggested that dried roots of the plant might be placed in simple bags and used in a very low cost metal ion removal system.« less

Role of soil rhizobacteria in phytoremediation of heavy metal contaminated soils*

PubMed Central

Jing, Yan-de; He, Zhen-li; Yang, Xiao-e

2007-01-01

Heavy metal pollution of soil is a significant environmental problem and has its negative impact on human health and agriculture. Rhizosphere, as an important interface of soil and plant, plays a significant role in phytoremediation of contaminated soil by heavy metals, in which, microbial populations are known to affect heavy metal mobility and availability to the plant through release of chelating agents, acidification, phosphate solubilization and redox changes, and therefore, have potential to enhance phytoremediation processes. Phytoremediation strategies with appropriate heavy metal-adapted rhizobacteria have received more and more attention. This article paper reviews some recent advances in effect and significance of rhizobacteria in phytoremediation of heavy metal contaminated soils. There is also a need to improve our understanding of the mechanisms involved in the transfer and mobilization of heavy metals by rhizobacteria and to conduct research on the selection of microbial isolates from rhizosphere of plants growing on heavy metal contaminated soils for specific restoration programmes. PMID:17323432

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…

Assessment of Heavy Metal Contamination in Marine Sediments of East Coast of Tamil Nadu Affected by Different Pollution Sources.

PubMed

Harikrishnan, N; Ravisankar, R; Chandrasekaran, A; Suresh Gandhi, M; Kanagasabapathy, K V; Prasad, M V R; Satapathy, K K

2017-08-15

The aim of this study was to determine the concentration of heavy metals in the sediments of Periyakalapet to Parangipettai coast, east coast of Tamil Nadu, by using energy-dispersive X-ray fluorescence (EDXRF) technique. The average heavy metal concentrations in the sediment samples were found in the order Al>Fe>Ca>Ti>K>Mg>Mn>Ba>V>Cr>Zn>La>Ni>Pb>Co>Cd>Cu. The average heavy metal concentrations were below the world crustal average. The degree of contamination by heavy metals was evaluated using pollution indices. The results of pollution indices revealed that titanium (Ti) and cadmium (Cd) were significantly enriched in sediments. Pearson correlation analysis was performed among heavy metal concentrations to know the existing relationship between them. Multivariate statistical technique was employed to identify the heavy metal pollution sources. Copyright © 2017 Elsevier Ltd. All rights reserved.

Detection of heavy metal by paper-based microfluidics.

PubMed

Lin, Yang; Gritsenko, Dmitry; Feng, Shaolong; Teh, Yi Chen; Lu, Xiaonan; Xu, Jie

2016-09-15

Heavy metal pollution has shown great threat to the environment and public health worldwide. Current methods for the detection of heavy metals require expensive instrumentation and laborious operation, which can only be accomplished in centralized laboratories. Various microfluidic paper-based analytical devices have been developed recently as simple, cheap and disposable alternatives to conventional ones for on-site detection of heavy metals. In this review, we first summarize current development of paper-based analytical devices and discuss the selection of paper substrates, methods of device fabrication, and relevant theories in these devices. We then compare and categorize recent reports on detection of heavy metals using paper-based microfluidic devices on the basis of various detection mechanisms, such as colorimetric, fluorescent, and electrochemical methods. To finalize, the future development and trend in this field are discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

Combining multitracing and 2D-modelling to identify the dynamic of heavy metals during flooding.

NASA Astrophysics Data System (ADS)

Hissler, C.; Hostache, R.; Matgen, P.; Tosheva, Z.; David, E.; Bates, P.; Stille, P.

2012-04-01

Recent years have seen a growing awareness of the wider environmental significance of the sediment loads transported by rivers and streams. This includes the importance of suspended sediment in transporting heavy metals and the potential for these trace elements to be desorbed from the particles to the solution. That threaten the water quality and can cause severe impacts in downstream areas like wetlands and floodplains. Contemporary data on the sediment loads of rivers provide clear evidence of significant recent changes in the sediment fluxes and of several rivers in response to human activities. For instance, Trace elements (including heavy metals) that are currently considered to be undisturbed by human activities and used as tracers of continental crust derived material have become more and more involved in industrial processes. Mathematical models validated by in situ experimentations are the only available tool to predict the consequences of natural as well as man-induced environmental changes and impacts on sediment dynamics. They are approximate representations of complex natural systems and the evaluation of a model with respect to its ability to reproduce multiple criteria and behaviour of a real system is still problematic. Interactions between modellers and experimentalists improve significantly the interpretation of the modelling output and led to formulate more realistic assumptions on the behaviour of natural systems. The geochemical information, which appeared to be non-correlated with the hydrological standard parameters, provides new information and contributes to give an "orthogonal view" on the hydrologic system behaviour. Regarding the recent development in geochemical tracer applications in models, the multi-tracer approach (natural vs anthropogenic; elemental concentration-isotopic signature-radionuclide activity) may be a necessity to decrease significantly the uncertainties in sediment transport modelling. The objective of this study is

Analysis of heavy metal sources in storm water from urban areas

NASA Astrophysics Data System (ADS)

Scherer, U.; Fuchs, S.

2009-04-01

The input of heavy metals into surface waters is a serious impairment of the aquatic environment. The emissions of heavy metals via point and diffuse pathways into the German river basins were thus quantified for the period of 1985 through 2005. The total emission into the German river systems decreased for each metal during the observed period. This reduction is mainly caused by the decline of emissions via point sources. The measures taken by industry and implemented within the scope of a stringently water legislation have decisively contributed to an improvement of environmental conditions. Today's emissions of heavy metals into river basins of Germany are dominated by the input via diffuse pathways. One of the most important diffuse input is the storm water discharged from paved urban areas into the surface waters via storm sewers and combined sewer overflows especially for the metals copper, zinc and lead. The objective of this project was to identify the sources of these three heavy metals washed of from paved urban areas. The use of copper, zinc and lead on the outsides of buildings results in emissions to water and soil via rainwater due to weathering and runoff of soluble and insoluble metallic compounds. Copper and zinc are traditionally used materials in the building sector especially for roofs, gutters and facades. Lead, in contrast, plays only a subordinate role due to its more limited outdoor use. The corrosion rates vary widely. Climatic factors (temperature, humidity etc.), above all the presence of corrosive gases (sulphur dioxide, nitrogen oxide, ozone etc.) influence the corrosion processes. Estimates of industrial associations were referred to in order to determine the corrosion relevant metal surfaces. Heavy metal emissions caused by traffic are complex and depend on many parameters which vary by locality, time and substance. In principle, substances can be emitted by vehicles, the road surface and by maintenance. Emissions of copper, lead and

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

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

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

Can heavy metal pollution defend seed germination against heat stress? Effect of heavy metals (Cu(2+), Cd(2+) and Hg(2+)) on maize seed germination under high temperature.

PubMed

Deng, Benliang; Yang, Kejun; Zhang, Yifei; Li, Zuotong

2016-09-01

Heavy metal pollution, as well as greenhouse effect, has become a serious threat today. Both heavy metal and heat stresses can arrest seed germination. What response can be expected for seed germination under both stress conditions? Here, the effects of heavy metals (Cu(2+), Cd(2+) and Hg(2+)) on maize seed germination were investigated at 20 °C and 40 °C. Compared with 20 °C, heat stress induced thermodormancy. However, this thermodormancy could be significantly alleviated by the addition of a low concentration of heavy metals. Heavy metals, as well as heat stress induced H2O2 accumulation in germinating seeds. Interestingly, this low concentration of heavy metal that promoted seed germination could be partly blocked by DMTU (a specific ROS scavenger), irrespective of temperature. Accordingly, H2O2 addition reinforced this promoting effect on seed germination, which was induced by a low concentration of heavy metal. Furthermore, we found that the NADPH oxidase derived ROS was required for seed germination promoted by the heavy metals. Subsequently, treatment of seeds with fluridone (a specific inhibitor of ABA) or ABA significantly alleviated or aggravated thermodormancy, respectively. However, this alleviation or aggravation could be partly attenuated by a low concentration of heavy metals. In addition, germination that was inhibited by high concentrations of heavy metals was also partly reversed by fluridone. The obtained results support the idea that heavy metal-mediated ROS and hormone interaction can finally affect the thermodormancy release or not. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

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

Heavy metal resistant endophytic fungi isolated from Nypa fruticans in Kuching Wetland National Park

NASA Astrophysics Data System (ADS)

Choo, Jenny; Sabri, Nuraini Binti Mohd; Tan, Daniel; Mujahid, Aazani; Müller, Moritz

2015-06-01

Heavy metal pollution is an environmental issue globally and the aim of this study was to isolate endophytic fungi from mangrove wetlands of Sarawak to assess and test their ability to grow in the presence of various heavy metals (copper (Cu), zinc (Zn), lead (Pb), and chromium (Cr)). Samples of Nypa fruticans were collected from Kuching Wetland National Park (KWNP) for subsequent endophyte isolation. Ninety-three (93) isolates were obtained and assessed and the most resistant isolates (growing at concentrations up to 1000 ppm) were identified using fungal primers ITS 1 and ITS 4. All of the endophytic fungi were identified to be closely related to Pestalotiopsis sp. and this is to our knowledge the first study reporting the ability of Pestalotiopsis sp. to grow at high concentrations of copper, lead, zinc and chromium. Our results highlight the potential of using endophytic fungi for the treatment of heavy metal pollution, for example as biosorbents.

Characterisation of heavy metal discharge into the Ria of Huelva.

PubMed

Sainz, A; Grande, J A; de la Torre, M L

2004-06-01

The Ria of Huelva estuary, in SW Spain, is known to be one of the most heavy metal contaminated estuaries in the world. River contribution to the estuary of dissolved Cu, Zn, Mn, Cr, Ni, Cd, and As were analysed for the period 1988-2001. The obtained mean values show that this contribution, both because of the magnitude of total metals (895.1 kg/h), composition, toxicity (8.7 kg/h of As+Cd+Pb) and persistence, is an incomparable case in heavy metal contamination of estuaries. The amount and typology of heavy metal discharge to the Ria of Huelva are related to freshwater flow (and, consequently, to rainfall); as a result, two different types of heavy metal discharge can be distinguished in the estuary: during low water (50% of the days), with only 19.3 kg/h of heavy metals, and during high water or flood (17% of the days), where daily maximum discharge of 72,475 kg of heavy metals were recorded, from which 1481 kg were of As, 470 kg of Pb, and 170 kg of Cd. In the most frequent situation (77% of the days), the Odiel River discharges from 90% to 100% of the freshwater received by the estuary. Despite this, the high concentration of heavy metals in the Tinto River water causes this river to discharge into the Ria of Huelva 12.5% of fluvial total dissolved metal load received by the estuary.

Concentration and transportation of heavy metals in vegetables and risk assessment of human exposure to bioaccessible heavy metals in soil near a waste-incinerator site, South China.

PubMed

Li, Ning; Kang, Yuan; Pan, Weijian; Zeng, Lixuan; Zhang, Qiuyun; Luo, Jiwen

2015-07-15

There is limited study focusing on the bioaccumulation of heavy metals in vegetables and human exposure to bioaccessible heavy metals in soil. In the present study, heavy metal concentrations (Cr, Ni, Cu, Pb and Cd) were measured in five types of vegetables, soil, root, and settled air particle samples from two sites (at a domestic waste incinerator and at 20km away from the incinerator) in Guangzhou, South China. Heavy metal concentrations in soil were greater than those in aerial parts of vegetables and roots, which indicated that vegetables bioaccumulated low amount of heavy metals from soil. The similar pattern of heavy metal (Cr, Cd) was found in the settled air particle samples and aerial parts of vegetables from two sites, which may suggest that foliar uptake may be an important pathway of heavy metal from the environment to vegetables. The highest levels of heavy metals were found in leaf lettuce (125.52μg/g, dry weight) and bitter lettuce (71.2μg/g) for sites A and B, respectively, followed by bitter lettuce and leaf lettuce for sites A and B, respectively. Swamp morning glory accumulated the lowest amount of heavy metals (81.02μg/g for site A and 53.2μg/g for site B) at both sites. The bioaccessibility of heavy metals in soil ranged from Cr (2%) to Cu (71.78%). Risk assessment showed that Cd and Pb in soil samples resulted in the highest non-cancer risk and Cd would result in unacceptable cancer risk for children and risk. The non-dietary intake of soil was the most important exposure pathway, when the bioaccessibility of heavy metals was taken into account. Copyright © 2015 Elsevier B.V. All rights reserved.

A novel heavy metal ATPase peptide from Prosopis juliflora is involved in metal uptake in yeast and tobacco.

PubMed

Keeran, Nisha S; Ganesan, G; Parida, Ajay K

2017-04-01

Heavy metal pollution of agricultural soils is one of the most severe ecological problems in the world. Prosopis juliflora, a phreatophytic tree species, grows well in heavy metal laden industrial sites and is known to accumulate heavy metals. Heavy Metal ATPases (HMAs) are ATP driven heavy metal pumps that translocate heavy metals across biological membranes thus helping the plant in heavy metal tolerance and phytoremediation. In the present study we have isolated and characterized a novel 28.9 kDa heavy metal ATPase peptide (PjHMT) from P. juliflora which shows high similarity to the C-terminal region of P 1B ATPase HMA1. It also shows the absence of the invariant signature sequence DKTGT, and the metal binding CPX motif but the presence of conserved regions like MVGEGINDAPAL (ATP binding consensus sequence), HEGGTLLVCLNS (metal binding domain) and MLTGD, GEGIND and HEGG motifs which play important roles in metal transport or ATP binding. PjHMT, was found to be upregulated under cadmium and zinc stress. Heterologous expression of PjHMT in yeast showed a higher accumulation and tolerance of heavy metals in yeast. Further, transgenic tobacco plants constitutively expressing PjHMT also showed increased accumulation and tolerance to cadmium. Thus, this study suggests that the transport peptide from P. juliflora may have an important role in Cd uptake and thus in phytoremediation.

Monitoring of heavy metal levels in the major rivers and in residents' blood in Zhenjiang City, China, and assessment of heavy metal elimination via urine and sweat in humans.

PubMed

Sheng, Jianguo; Qiu, Wenhui; Xu, Bentuo; Xu, Hui; Tang, Chong

2016-06-01

The coastal areas of China face great challenges, owing to heavy metal contamination caused by rapid industrialization and urbanization. To our knowledge, this study is the first report of the levels of heavy metals in the major rivers of Zhenjiang, one of the most important cities of the Yangtze River Delta in China. In addition, we measured heavy metal levels in the blood of 76 residents of Zhenjiang. The results suggest that the presence of heavy metals in the blood may threaten human health and the distribution appeared to correspond to most highly populated areas and/or areas with high traffic. We also found that the concentration of heavy metals in human blood showed an accumulation effect with increase in age. Moreover, the levels of most heavy metals were lower in participants who regularly exercised than in those who did not. We studied heavy metal levels in the urine and sweat of another 17 volunteers to monitor the elimination of bioaccumulated heavy metal. Heavy metals were found in the urine and sweat of all the 17 participants and were more concentrated in sweat. Induced micturition and sweating appear to be potential methods for the elimination of heavy metals from the human body.

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

Antimicrobial resistance, heavy metal resistance and integron content in bacteria isolated from a South African tilapia aquaculture system.

PubMed

Chenia, Hafizah Y; Jacobs, Anelet

2017-11-21

Antibacterial compounds and metals co-select for antimicrobial resistance when bacteria harbour resistance genes towards both types of compounds, facilitating the proliferation and evolution of antimicrobial and heavy metal resistance. Antimicrobial and heavy metal resistance indices of 42 Gram-negative bacteria from a tilapia aquaculture system were determined to identify possible correlations between these phenotypes. Agar dilution assays were carried out to determine susceptibility to cadmium, copper, lead, mercury, chromate and zinc, while susceptibility to 21 antimicrobial agents was investigated by disk diffusion assays. Presence of merA, the mercury resistance gene, was determined by dot-blot hybridizations and PCR. Association of mercury resistance with integrons and transposon Tn21 was also investigated by PCR. Isolates displayed a high frequency of antimicrobial (erythromycin: 100%; ampicillin: 85%; trimethoprim: 78%) and heavy metal (Zn2+: 95%; Cd2+: 91%) resistance. No correlation was established between heavy metal and multiple antibiotic resistance indices. Significant positive correlations were observed between heavy metal resistance profiles, indices, Cu2+ and Cr3+ resistance with erythromycin resistance. Significant positive correlations were observed between merA (24%)/Tn21 (24%) presence and heavy metal resistance profiles and indices; however, significant negative correlations were obtained between integron-associated qacE∆1 (43%) and sulI (26%) gene presence and heavy metal resistance indices. Heavy metal and antimicrobial agents co-select for resistance, with fish-associated, resistant bacteria demonstrating simultaneous heavy metal resistance. Thus, care should be taken when using anti-fouling heavy metals as feed additives in aquaculture facilities.

Evaluating Heavy Metal Stress Levels in Rice Based on Remote Sensing Phenology.

PubMed

Liu, Tianjiao; Liu, Xiangnan; Liu, Meiling; Wu, Ling

2018-03-14

Heavy metal pollution of croplands is a major environmental problem worldwide. Methods for accurately and quickly monitoring heavy metal stress have important practical significance. Many studies have explored heavy metal stress in rice in relation to physiological function or physiological factors, but few studies have considered phenology, which can be sensitive to heavy metal stress. In this study, we used an integrated Normalized Difference Vegetation Index (NDVI) time-series image set to extract remote sensing phenology. A phenological indicator relatively sensitive to heavy metal stress was chosen from the obtained phenological periods and phenological parameters. The Dry Weight of Roots (WRT), which directly affected by heavy metal stress, was simulated by the World Food Study (WOFOST) model; then, a feature space based on the phenological indicator and WRT was established for monitoring heavy metal stress. The results indicated that the feature space can distinguish the heavy metal stress levels in rice, with accuracy greater than 95% for distinguishing the severe stress level. This finding provides scientific evidence for combining rice phenology and physiological characteristics in time and space, and the method is useful to monitor heavy metal stress in rice.

A Study on Characteristics of Atmospheric Heavy Metals in Subway Station

PubMed Central

Kim, Chun-Huem; Yoo, Dong-Chul; Kwon, Young-Min; Han, Woong-Soo; Kim, Gi-Sun; Park, Mi-Jung; Kim, Young Soon

2010-01-01

In this study, we investigated the atmospheric heavy metal concentrations in the particulate matter inside the subway stations of Seoul. In particular, we examined the correlation between the heavy metals and studied the effect of the heavy metals on cell proliferation. In six selected subway stations in Seoul, particulate matter was captured at the platforms and 11 types of heavy metals were analyzed. The results showed that the mean concentration of iron was the highest out of the heavy metals in particulate matter, followed by copper, potassium, calcium, zinc, nickel, sodium, manganese, magnesium, chromium and cadmium in that order. The correlation analysis showed that the correlations between the heavy metals was highest in the following order: (Cu vs Zn) , (Ca vs Na) , (Ca vs Mn) , (Ni vs Cr) , (Na vs Mn) , (Cr vs Cd) , (Zn vs Cd) , (Cu vs Cd) , (Ni vs Cd) , (Cu vs Ni) , (K vs Zn) , (Cu vs K) , (Cu vs Cr) , (K vs Cd) , (Zn vs Cr) , (K vs Ni) , (Zn vs Ni) , (K vs Cr) , and (Fe vs Cu) . The correlation coefficient between zinc and copper was 0.937, indicating the highest correlation. Copper, zinc, nickel, chromium and cadmium, which are generated from artificial sources in general, showed correlations with many of the other metals and the correlation coefficients were also relatively high. The effect of the heavy metals on cell proliferation was also investigated in this study. Cultured cell was exposed to 10 mg/l or 100 mg/l of iron, copper, calcium, zinc, nickel, manganese, magnesium, chromium and cadmium for 24 hours. The cell proliferation in all the heavy metal-treated groups was not inhibited at 10 mg/l of the heavy metal concentration. The only exception to this was with the cadmium-treated group which showed a strong cell proliferation inhibition. This study provides the fundamental data for the understanding of simultaneous heavy metal exposure tendency at the time of particulate matter exposure in subway stations and the identification of heavy metal

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.

Heavy Metal - Exploring a magnetised metallic asteroid

NASA Astrophysics Data System (ADS)

Wahlund, Jan-Erik; Andrews, David; Futaana, Yoshifumi; Masters, Adam; Thomas, Nicolas; De Sanctis, Maria Cristina; Herique, Alain; Retherford, Kurt; Tortora, Paolo; Trigo-Rodriguez, Joseph; Ivchenko, Nickolay; Simon, Sven

2017-04-01

We propose a spacecraft mission (Heavy Metal) to orbit and explore (16) Psyche - the largest M-class metallic asteroid in the main belt. Recent estimates of the shape, 279×232×189 km and mass, 2.7×10(19) kg make it one of the largest and densest of asteroids, and together with the high surface radar reflectivity and the spectral data measured from Earth it is consistent with a bulk composition rich in iron-nickel. The M5 mission Heavy Metal will investigate if (16) Psyche is the exposed metallic core of a planetesimal, formed early enough to melt and differentiate. High-resolution mapping of the surface in optical, IR, UV and radar wavebands, along with the determination of the shape and gravity field will be used to address the formation and subsequent evolution of (16) Psyche, determining the origin of metallic asteroids. It is conceivable that a cataclysmic collision with a second body led to the ejection of all or part of the differentiated core of the parent body. Measurements at (16) Psyche therefore provide a possibility to directly examine an iron-rich planetary core, similar to that expected at the center of all the major planets including Earth. A short-lived dynamo producing a magnetic field early in the life of (16) Psyche could have led to a remnant field (of tens of micro Tesla) being preserved in the body today. (16) Psyche is embedded in the variable flow of the solar wind. Whereas planetary magnetospheres and induced magnetospheres are the result of intense dynamo fields and dense conductive ionospheres presenting obstacles to the solar wind, (16) Psyche may show an entirely new 'class' of interaction as a consequence of its lack of a significant atmosphere, the extremely high bulk electrical conductivity of the asteroid, and the possible presence of intense magnetic fields retained in iron-rich material. The small characteristic scale of (16) Psyche ( 200 km) firmly places any solar wind interaction in the "sub-MHD" scale, in which kinetic

Co-occurrence correlations of heavy metals in sediments revealed using network analysis.

PubMed

Liu, Lili; Wang, Zhiping; Ju, Feng; Zhang, Tong

2015-01-01

In this study, the correlation-based study was used to identify the co-occurrence correlations among metals in marine sediment of Hong Kong, based on the long-term (from 1991 to 2011) temporal and spatial monitoring data. 14 stations out of the total 45 marine sediment monitoring stations were selected from three representative areas, including Deep Bay, Victoria Harbour and Mirs Bay. Firstly, Spearman's rank correlation-based network analysis was conducted as the first step to identify the co-occurrence correlations of metals from raw metadata, and then for further analysis using the normalized metadata. The correlations patterns obtained by network were consistent with those obtained by the other statistic normalization methods, including annual ratios, R-squared coefficient and Pearson correlation coefficient. Both Deep Bay and Victoria Harbour have been polluted by heavy metals, especially for Pb and Cu, which showed strong co-occurrence with other heavy metals (e.g. Cr, Ni, Zn and etc.) and little correlations with the reference parameters (Fe or Al). For Mirs Bay, which has better marine sediment quality compared with Deep Bay and Victoria Harbour, the co-occurrence patterns revealed by network analysis indicated that the metals in sediment dominantly followed the natural geography process. Besides the wide applications in biology, sociology and informatics, it is the first time to apply network analysis in the researches of environment pollutions. This study demonstrated its powerful application for revealing the co-occurrence correlations among heavy metals in marine sediments, which could be further applied for other pollutants in various environment systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Biosorption of heavy metals in fluoritum decoction by fungal mycelium].

PubMed

Cui, Pei-wu; Hu, Wei; Hu, Ya-qiang; Tan, Zhao-yang

2014-09-01

To explore the biosorption technology of heavy metals in Fluoritum decoction by fungal mycelium. Four factors including fungal mycelium amount, adsorption time, pH value and temperature were employed to estimate the fungal biomass adsorption conditions for removing the heavy metals in Fluoritum decoction. Then an orthogonal experimental design was taken to optimize the biosorption process, and the removal efficiency was also evaluated. Under the optimized conditions of 1.0 g/50 mL Fluoritum decoction, 3 hours adsorption time, pH 5.0 and 40 degrees C, a result of 70.12% heavy metals removal rate was accomplished with 35.99% calcium ion loss. The study indicates that removing of heavy metals in Fluoritum decoction through fungal mycelium is feasible, and the experiment results can also provide a basis for further research on biosorption of heavy metals in traditional Chinese medicine

Electrokinetic treatment of an agricultural soil contaminated with heavy metals.

PubMed

Figueroa, Arylein; Cameselle, Claudio; Gouveia, Susana; Hansen, Henrik K

2016-07-28

The high organic matter content in agricultural soils tends to complex and retain contaminants such as heavy metals. Electrokinetic remediation was tested in an agricultural soil contaminated with Co(+2), Zn(+2), Cd(+2), Cu(+2), Cr(VI), Pb(+2) and Hg(+2). The unenhanced electrokinetic treatment was not able to remove heavy metals from the soil due to the formation of precipitates in the alkaline environment in the soil section close to the cathode. Moreover, the interaction between metals and organic matter probably limited metal transportation under the effect of the electric field. Citric acid and ethylenediaminetetraacetic acid (EDTA) were used in the catholyte as complexing agents in order to enhance the extractability and removal of heavy metals from soil. These complexing agents formed negatively charged complexes that migrated towards the anode. The acid front electrogenerated at the anode favored the dissolution of heavy metals that were transported towards the cathode. The combined effect of the soil pH and the complexing agents resulted in the accumulation of heavy metals in the center of the soil specimen.

Space-time quantitative source apportionment of soil heavy metal concentration increments.

PubMed

Yang, Yong; Christakos, George; Guo, Mingwu; Xiao, Lu; Huang, Wei

2017-04-01

Assessing the space-time trends and detecting the sources of heavy metal accumulation in soils have important consequences in the prevention and treatment of soil heavy metal pollution. In this study, we collected soil samples in the eastern part of the Qingshan district, Wuhan city, Hubei Province, China, during the period 2010-2014. The Cd, Cu, Pb and Zn concentrations in soils exhibited a significant accumulation during 2010-2014. The spatiotemporal Kriging technique, based on a quantitative characterization of soil heavy metal concentration variations in terms of non-separable variogram models, was employed to estimate the spatiotemporal soil heavy metal distribution in the study region. Our findings showed that the Cd, Cu, and Zn concentrations have an obvious incremental tendency from the southwestern to the central part of the study region. However, the Pb concentrations exhibited an obvious tendency from the northern part to the central part of the region. Then, spatial overlay analysis was used to obtain absolute and relative concentration increments of adjacent 1- or 5-year periods during 2010-2014. The spatial distribution of soil heavy metal concentration increments showed that the larger increments occurred in the center of the study region. Lastly, the principal component analysis combined with the multiple linear regression method were employed to quantify the source apportionment of the soil heavy metal concentration increments in the region. Our results led to the conclusion that the sources of soil heavy metal concentration increments should be ascribed to industry, agriculture and traffic. In particular, 82.5% of soil heavy metal concentration increment during 2010-2014 was ascribed to industrial/agricultural activities sources. Using STK and SOA to obtain the spatial distribution of heavy metal concentration increments in soils. Using PCA-MLR to quantify the source apportionment of soil heavy metal concentration increments. Copyright © 2017

Heavy Metal Music and Reckless Behavior among Adolescents.

ERIC Educational Resources Information Center

Arnett, Jeffrey

1991-01-01

Fifty-four male and 30 female adolescents who like heavy metal music were compared on various outcome variables to 56 male and 105 female peers who do not like it. Those who like heavy metal report a wider range of reckless behavior than those who do not like it. (SLD)

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

Heavy metals in the volcanic environment and thyroid cancer.

PubMed

Vigneri, R; Malandrino, P; Gianì, F; Russo, M; Vigneri, P

2017-12-05

In the last two decades thyroid cancer incidence has increased worldwide more than any other cancer. Overdiagnosis of subclinical microcarcinomas has certainly contributed to this increase but many evidences indicate that a true increase, possibly due to environmental factors, has also occurred. Thyroid cancer incidence is markedly increased in volcanic areas. Thus, the volcanic environment is a good model to investigate the possible factors favoring thyroid cancer. In the volcanic area of Mt. Etna in Sicily, as well as in other volcanic areas, a non-anthropogenic pollution with heavy metals has been documented, a consequence of gas, ash and lava emission. Soil, water and atmosphere contamination, via the food chain, biocontaminate the residents as documented by high levels in the urines and the scalp hair compared to individuals living in adjacent non-volcanic areas. Trace amounts of metals are essential nutrients but, at higher concentrations, can be toxic for living cells. Metals can behave both as endocrine disruptors, perturbing the hormonal system, and as carcinogens, promoting malignant transformation. Similarly to other carcinogens, the transforming effect of heavy metals is higher in developing organisms as the fetus (contaminated via the mother) and individuals in early childhood. In the last decades environment metal pollution has greatly increased in industrialized countries. Although still within the "normal" limits for each single metal the hormesis effect (heavy metal activity at very low concentration because of biphasic, non linear cell response) and the possible potentiation effect resulting from the mixture of different metals acting synergistically can explain cell damage at very low concentrations. The effect of metals on the human thyroid is poorly studied: for some heavy metals no data are available. The scarce studies that have been performed mainly focus on metal effect as thyroid endocrine disruptors. The metal concentration in tissues has

Ecological risk and pollution history of heavy metals in Nansha mangrove, South China.

PubMed

Wu, Qihang; Tam, Nora F Y; Leung, Jonathan Y S; Zhou, Xizhen; Fu, Jie; Yao, Bo; Huang, Xuexia; Xia, Lihua

2014-06-01

Owing to the Industrial Revolution in the late 1970s, heavy metal pollution has been regarded as a serious threat to mangrove ecosystems in the region of the Pearl River Estuary, potentially affecting human health. The present study attempted to characterize the ecological risk of heavy metals (Cd, Cr, Cu, Mn, Ni, Pb and Zn) in Nansha mangrove, South China, by estimating their concentrations in the surface sediment. In addition, the pollution history of heavy metals was examined by determining the concentrations of heavy metals along the depth gradient. The phytoremediation potential of heavy metals by the dominant plants in Nansha mangrove, namely Sonneratia apetala and Cyperus malaccensis, was also studied. Results found that the surface sediment was severely contaminated with heavy metals, probably due to the discharge of industrial sewage into the Pearl River Estuary. Spatial variation of heavy metals was generally unobvious. The ecological risk of heavy metals was very high, largely due to Cd contamination. All heavy metals, except Mn, decreased with depth, indicating that heavy metal pollution has been deteriorating since 1979. Worse still, the dominant plants in Nansha mangrove had limited capability to remove the heavy metals from sediment. Therefore, we propose that immediate actions, such as regulation of discharge standards of industrial sewage, should be taken by the authorities concerned to mitigate the ecological risk posed by heavy metals. Copyright © 2014 Elsevier Inc. All rights reserved.

Ecological risk assessment on heavy metals in soils: Use of soil diffuse reflectance mid-infrared Fourier-transform spectroscopy

PubMed Central

Wang, Cheng; Li, Wei; Guo, Mingxing; Ji, Junfeng

2017-01-01

The bioavailability of heavy metals in soil is controlled by their concentrations and soil properties. Diffuse reflectance mid-infrared Fourier-transform spectroscopy (DRIFTS) is capable of detecting specific organic and inorganic bonds in metal complexes and minerals and therefore, has been employed to predict soil composition and heavy metal contents. The present study explored the potential of DRIFTS for estimating soil heavy metal bioavailability. Soil and corresponding wheat grain samples from the Yangtze River Delta region were analyzed by DRIFTS and chemical methods. Statistical regression analyses were conducted to correlate the soil spectral information to the concentrations of Cd, Cr, Cu, Zn, Pb, Ni, Hg and Fe in wheat grains. The principal components in the spectra influencing soil heavy metal bioavailability were identified and used in prediction model construction. The established soil DRIFTS-based prediction models were applied to estimate the heavy metal concentrations in wheat grains in the mid-Yangtze River Delta area. The predicted heavy metal concentrations of wheat grain were highly consistent with the measured levels by chemical analysis, showing a significant correlation (r2 > 0.72) with acceptable root mean square error RMSE. In conclusion, DRIFTS is a promising technique for assessing the bioavailability of soil heavy metals and related ecological risk. PMID:28198802

Heavy metal pollution and health risk assessment in the Wei River in China.

PubMed

Yang, Xuefu; Duan, Jinming; Wang, Lei; Li, Wei; Guan, Jianling; Beecham, Simon; Mulcahy, Dennis

2015-03-01

From data collected monthly at 26 monitoring cross sections in the Wei River in the Shaanxi Region of China during the period 2008-2012, the temporal pollution characteristics of heavy metals (Hg, Cd, Cr(VI), Pb, and As) were analyzed based on a heavy metal pollution index (HPI). The monthly HPI values of the five heavy metals in the river fluctuated greatly in 2008 and then declined gradually with time. This general trend of reduction in HPI appears not to have a seasonal variation and most likely resulted from the continued improvement in heavy metal pollution control strategies implemented by local environmental agencies combined with a significant improvement in wastewater treatment capacities. Among the five heavy metals, Cd and Pb were below 0.1 and 3 μg L(-1), respectively, at all the sampling points in the studied areas in the year 2012. The detection rates of As, Hg, and Cr(VI) were in the order of Hg > Cr(VI) > As. Hg, Cr(VI), and As exceeded, in a month of the dry season in 2012, the standard limits for category III surface waters according to the China Environment Quality Standards for Surface Water (CEQSSW). Based on the assessment using the HPI method, the pollution status of these heavy metals in water of the Wei River in the Shaanxi Region was generally at an acceptable level, but exhibited distinctive characteristics between the main stream river and tributaries. Most of the tributaries were more seriously polluted than the main river. A health risk assessment was conducted based on the Human Health Risk Assessment (HHRA) method recommended by the United States Environmental Protection Agency (USEPA). Apart from As, the health risk for the five heavy metals in the region were at acceptable levels for drinking water sources (hazard quotient (HQ) < 1, carcinogenic risk (CR) ranged from 10(-4)-10(-6)) according to the Risk Assessment Guidance for Superfund (RAGS), USEPA. Arsenic was identified as the most important pollutant of concern

Soil heavy metal contamination and health risks associated with artisanal gold mining in Tongguan, Shaanxi, China.

PubMed

Xiao, Ran; Wang, Shuang; Li, Ronghua; Wang, Jim J; Zhang, Zengqiang

2017-07-01

Soil contamination with heavy metals due to mining activities poses risks to ecological safety and human well-being. Limited studies have investigated heavy metal pollution due to artisanal mining. The present study focused on soil contamination and the health risk in villages in China with historical artisanal mining activities. Heavy metal levels in soils, tailings, cereal and vegetable crops were analyzed and health risk assessed. Additionally, a botany investigation was conducted to identify potential plants for further phytoremediation. The results showed that soils were highly contaminated by residual tailings and previous mining activities. Hg and Cd were the main pollutants in soils. The Hg and Pb concentrations in grains and some vegetables exceeded tolerance limits. Moreover, heavy metal contents in wheat grains were higher than those in maize grains, and leafy vegetables had high concentrations of metals. Ingestion of local grain-based food was the main sources of Hg, Cd, and Pb intake. Local residents had high chronic risks due to the intake of Hg and Pb, while their carcinogenic risk associated with Cd through inhalation was low. Three plants (Erigeron canadensis L., Digitaria ciliaris (Retz.) Koel., and Solanum nigrum L.) were identified as suitable species for phytoremediation. Copyright © 2017. Published by Elsevier Inc.

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.

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...

Basis of genetic adaptation to heavy metal stress in the acidophilic green alga Chlamydomonas acidophila.

PubMed

Puente-Sánchez, Fernando; Díaz, Silvia; Penacho, Vanessa; Aguilera, Angeles; Olsson, Sanna

2018-07-01

To better understand heavy metal tolerance in Chlamydomonas acidophila, an extremophilic green alga, we assembled its transcriptome and measured transcriptomic expression before and after Cd exposure in this and the neutrophilic model microalga Chlamydomonas reinhardtii. Genes possibly related to heavy metal tolerance and detoxification were identified and analyzed as potential key innovations that enable this species to live in an extremely acid habitat with high levels of heavy metals. In addition we provide a data set of single orthologous genes from eight green algal species as a valuable resource for comparative studies including eukaryotic extremophiles. Our results based on differential gene expression, detection of unique genes and analyses of codon usage all indicate that there are important genetic differences in C. acidophila compared to C. reinhardtii. Several efflux family proteins were identified as candidate key genes for adaptation to acid environments. This study suggests for the first time that exposure to cadmium strongly increases transposon expression in green algae, and that oil biosynthesis genes are induced in Chlamydomonas under heavy metal stress. Finally, the comparison of the transcriptomes of several acidophilic and non-acidophilic algae showed that the Chlamydomonas genus is polyphyletic and that acidophilic algae have distinctive aminoacid usage patterns. Copyright © 2018 Elsevier B.V. All rights reserved.

Responses of Plant Proteins to Heavy Metal Stress—A Review

PubMed Central

Hasan, Md. Kamrul; Cheng, Yuan; Kanwar, Mukesh K.; Chu, Xian-Yao; Ahammed, Golam J.; Qi, Zhen-Yu

2017-01-01

Plants respond to environmental pollutants such as heavy metal(s) by triggering the expression of genes that encode proteins involved in stress response. Toxic metal ions profoundly affect the cellular protein homeostasis by interfering with the folding process and aggregation of nascent or non-native proteins leading to decreased cell viability. However, plants possess a range of ubiquitous cellular surveillance systems that enable them to efficiently detoxify heavy metals toward enhanced tolerance to metal stress. As proteins constitute the major workhorses of living cells, the chelation of metal ions in cytosol with phytochelatins and metallothioneins followed by compartmentalization of metals in the vacuoles as well as the repair of stress-damaged proteins or removal and degradation of proteins that fail to achieve their native conformations are critical for plant tolerance to heavy metal stress. In this review, we provide a broad overview of recent advances in cellular protein research with regards to heavy metal tolerance in plants. We also discuss how plants maintain functional and healthy proteomes for survival under such capricious surroundings. PMID:28928754

Heavy Metal Blood Test: MedlinePlus Lab Test Information

MedlinePlus

... Internet]. Washington D.C.: American Association for Clinical Chemistry; c2001–2017. Heavy Metals: Common Questions [updated 2016 ... Internet]. Washington D.C.: American Association for Clinical Chemistry; c2001–2017. Heavy Metals: The Test [updated 2016 ...

[Heavy metal pollution ecology of macro-fungi: research advances and expectation].

PubMed

Zhou, Qi-xing; An, Xin-long; Wei, Shu-he

2008-08-01

Macro-fungi are the main component of biosphere and one of the ecological resources, and play very important roles in matter cycling and in maintaining ecological balances. This paper summarized and reviewed the research advances in the eco-toxicological effects of heavy metals on macro-fungi, the bioaccumulation function of macro-fungi on heavy metals, the ecological adaptation mechanisms of macro-fungi to heavy metal pollution, the role of macro-fungi as a bio-indicator of heavy metal pollution, and the potential of macro-fungi in the ecological remediation of contaminated environment. To strengthen the researches on the heavy metal pollution ecology of macro-fungi would be of practical significance in the reasonable utilization of macro-fungi resources and in the ecological remediation of contaminated environment.

[Temporal-spatial difference of ecotoxicity and heavy metals pollution in Shima catchment, Dongguan].

PubMed

Gao, Lei; Chen, Jian-Yao; Ke, Zhi-Ting; Wang, Jiang; Yang, Xue-Yun; Shimizu, Yuta

2013-08-01

Shima River, a tributary of Dongjiang River, located in Dongguan City of Guangdong Province, has been seriously polluted in the last 30 years. Water samples were collected from the river and the aquifer and the soil samples were collected as well in the wet (June) and dry (February) season to investigate the temporal and spatial variations of water quality in terms of heavy metal concentrations and inhibition rate of the luminescent bacterium (Vibrio fischeri, LUMIStox 300). Heavy metal concentrations and inhibition rate in river water were found decreasing from the upstream to the downstream, with metal concentrations exceeding the national surface water quality standard (Class I) for all samples and a highest inhibition of 38.34% (equivalent to moderate toxic) at R1 in the dry season. Significant difference (P < 0.01 or P < 0.001) in the wet and dry season was identified in both metal concentrations and inhibition rate, except at R11, which showed a inhibition rate of 15.56%, higher than those in all other samples in the wet season. Inhibition rate at GW4, GW5 and GW6 showed significant difference (P < 0.01 or P < 0.001) in the two periods, and the highest inhibition rate (15.88%) at GW6 in the dry season was considered as low in toxicity. The positive correlations (P < 0.05 or P < 0.01) between heavy metals (Zn, Fe, Mn and Ni) and inhibition rate were identified with correlation coefficients of 0.452, 0.567, 0.726 and 0.475, respectively. Heavy metal pollution of soil (Cu, Ni and Zn) near the river was due to the interaction between the river and the groundwater. Cd was heavily accumulated in the soil, while elevated concentrations of Fe and Mn were found in the river and the groundwater was heavily polluted by Ni.

Comparison of heavy metals and uranium removal using adsorbent in soil

NASA Astrophysics Data System (ADS)

Choi, Jaeyoung; Yun, Hunsik

2017-04-01

This study investigates heavy metals (As, Ni, Zn, Cd, and Pb) and uranium removal onto geomaterials (limestone, black shale, and concrete) and biosorbents (Pseudomonas putida and starfish) from waste in soil. Geomaterials or biosorbents with a high capacity for heavy metals and uranium can be obtained and employed of with little cost. For investigating the neutralization capacity, the change in pH, Eh, and EC as a function of time was quantified. The adsorption of heavy metals and uranium by the samples was influenced by pH, and increased with increasing heavy metals and uranium concentrations. Dead cells adsorbed the largest quantity of all heavy metals than lother sorbents. The adsorption capacity followed the order: U(VI) > Pb > Cd > Ni. The results also suggest that bacterial membrane cells can be used successfully in the treatment of high strength metal-contaminated soil.

Human health risk assessment of heavy metals in urban stormwater.

PubMed

Ma, Yukun; Egodawatta, Prasanna; McGree, James; Liu, An; Goonetilleke, Ashantha

2016-07-01

Toxic chemical pollutants such as heavy metals (HMs) are commonly present in urban stormwater. These pollutants can pose a significant risk to human health and hence a significant barrier for urban stormwater reuse. The primary aim of this study was to develop an approach for quantitatively assessing the risk to human health due to the presence of HMs in stormwater. This approach will lead to informed decision making in relation to risk management of urban stormwater reuse, enabling efficient implementation of appropriate treatment strategies. In this study, risks to human health from heavy metals were assessed as hazard index (HI) and quantified as a function of traffic and land use related parameters. Traffic and land use are the primary factors influencing heavy metal loads in the urban environment. The risks posed by heavy metals associated with total solids and fine solids (<150μm) were considered to represent the maximum and minimum risk levels, respectively. The study outcomes confirmed that Cr, Mn and Pb pose the highest risks, although these elements are generally present in low concentrations. The study also found that even though the presence of a single heavy metal does not pose a significant risk, the presence of multiple heavy metals could be detrimental to human health. These findings suggest that stormwater guidelines should consider the combined risk from multiple heavy metals rather than the threshold concentration of an individual species. Furthermore, it was found that risk to human health from heavy metals in stormwater is significantly influenced by traffic volume and the risk associated with stormwater from industrial areas is generally higher than that from commercial and residential areas. Copyright © 2016 Elsevier B.V. All rights reserved.

Improving crop tolerance to heavy metal stress by polyamine application.

PubMed

Soudek, Petr; Ursu, Marina; Petrová, Šárka; Vaněk, Tomáš

2016-12-15

Many areas have been heavily contaminated by heavy metals from industry and are not suitable for food production. The consumption of contaminated foods represents a health risk in humans, although some heavy metals are essential at low concentrations. Increasing the concentrations of essential elements in foods is one goal to improve nutrition. The aim of this study was to increase the accumulation of heavy metals in plant foods by the external application of putrescine. The levels of cadmium, zinc and iron were measured in different vegetables grown in hydroponic medium supplemented with heavy metals and compared with those grown in a reference medium. The estimated daily intake, based on the average daily consumption for various vegetable types, and the influence of polyamines on metal uptake were calculated. Copyright © 2016 Elsevier Ltd. All rights reserved.

Heavy metals in locus ceruleus and motor neurons in motor neuron disease.

PubMed

Pamphlett, Roger; Kum Jew, Stephen

2013-12-12

The causes of sporadic amyotrophic lateral sclerosis (SALS) and other types of motor neuron disease (MND) remain largely unknown. Heavy metals have long been implicated in MND, and it has recently been shown that inorganic mercury selectively enters human locus ceruleus (LC) and motor neurons. We therefore used silver nitrate autometallography (AMG) to look for AMG-stainable heavy metals (inorganic mercury and bismuth) in LC and motor neurons of 24 patients with MND (18 with SALS and 6 with familial MND) and in the LC of 24 controls. Heavy metals in neurons were found in significantly more MND patients than in controls when comparing: (1) the presence of any versus no heavy metal-containing LC neurons (MND 88%, controls 42%), (2) the median percentage of heavy metal-containing LC neurons (MND 9.5%, control 0.0%), and (3) numbers of individuals with heavy metal-containing LC neurons in the upper half of the percentage range (MND 75%, controls 25%). In MND patients, 67% of remaining spinal motor neurons contained heavy metals; smaller percentages were found in hypoglossal, nucleus ambiguus and oculomotor neurons, but none in cortical motor neurons. The majority of MND patients had heavy metals in both LC and spinal motor neurons. No glia or other neurons, including neuromelanin-containing neurons of the substantia nigra, contained stainable heavy metals. Uptake of heavy metals by LC and lower motor neurons appears to be fairly common in humans, though heavy metal staining in the LC, most likely due to inorganic mercury, was seen significantly more often in MND patients than in controls. The LC innervates many cell types that are affected in MND, and it is possible that MND is triggered by toxicant-induced interactions between LC and motor neurons.

Heavy metals in locus ceruleus and motor neurons in motor neuron disease

PubMed Central

2013-01-01

Background The causes of sporadic amyotrophic lateral sclerosis (SALS) and other types of motor neuron disease (MND) remain largely unknown. Heavy metals have long been implicated in MND, and it has recently been shown that inorganic mercury selectively enters human locus ceruleus (LC) and motor neurons. We therefore used silver nitrate autometallography (AMG) to look for AMG-stainable heavy metals (inorganic mercury and bismuth) in LC and motor neurons of 24 patients with MND (18 with SALS and 6 with familial MND) and in the LC of 24 controls. Results Heavy metals in neurons were found in significantly more MND patients than in controls when comparing: (1) the presence of any versus no heavy metal-containing LC neurons (MND 88%, controls 42%), (2) the median percentage of heavy metal-containing LC neurons (MND 9.5%, control 0.0%), and (3) numbers of individuals with heavy metal-containing LC neurons in the upper half of the percentage range (MND 75%, controls 25%). In MND patients, 67% of remaining spinal motor neurons contained heavy metals; smaller percentages were found in hypoglossal, nucleus ambiguus and oculomotor neurons, but none in cortical motor neurons. The majority of MND patients had heavy metals in both LC and spinal motor neurons. No glia or other neurons, including neuromelanin-containing neurons of the substantia nigra, contained stainable heavy metals. Conclusions Uptake of heavy metals by LC and lower motor neurons appears to be fairly common in humans, though heavy metal staining in the LC, most likely due to inorganic mercury, was seen significantly more often in MND patients than in controls. The LC innervates many cell types that are affected in MND, and it is possible that MND is triggered by toxicant-induced interactions between LC and motor neurons. PMID:24330485

[Investigation and analysis of heavy metal pollution related to soil-Panax notoginseng system].

PubMed

Chen, Lu; Mi, Yan-Hua; Lin, Xin; Liu, Da-Hui; Zeng, Min; Chen, Xiao-Yan

2014-07-01

In this study, five heavy metals contamination of soil and different parts of Panax notoginseng in the plantation area was investigated. Analysis of heavy metals correlation between the planting soil and P. notoginseng; and the absorption and accumulation characteristics and translocation of soil heavy metals by P. notoginseng plants was revealed. Through field investigation and laboratory analytical methods, analysis of China's 30 different soil P. notoginseng origin and content of heavy metals in five different parts of the P. notoginseng plant content of heavy metals. The results revealed that the soil heavy metals should not be neglected in the plantation area Referring to the national soil quality standards (GB15608-1995), the excessive degree of soil heavy metals pollution showed Hg > As > Cd > Cr in the plantation area, and Pb content of soil was in the scope of the standard. Refer to 'Green Industry Standards for Import and Export of Medical Plants and Preparations', the excessive degree of heavy metals content of P. notoginseng plants showed As > Pb > Cr > Cd, and Hg content of plants was in the scope of the standard. Concentrations of five heavy metals of underground parts of P. notoginseng plants are higher than aboveground, and heavy metals elements are more concentrated in the root, followed by the rhizome of P. notoginseng plants. Heavy metal accumulation characteristics of the different parts of the P. notoginseng of the overall performance is the root > the rhizome > the root tuber > leaves > stems. From the point of view BCF value analysis of various parts of the P. notoginseng plants to absorb heavy metals in soil, BCF values of all samples were less than 1, description P. notoginseng not belong Hyperaccumulator. From the view of transportation and related analysis of the soil-P. notoginseng systems, the rhizome of P. notoginseng and the content of As and Cr in soil was significantly correlated, the root of P. notoginseng and the content of Cd in

Hubble Friday - Heavy Metal Stars

NASA Image and Video Library

2017-12-08

Hubble rocks out with heavy metal stars! This 10.5-billion-year-old globular cluster, NGC 6496, is home to heavy-metal stars of a celestial kind! The stars comprising this spectacular spherical cluster are enriched with much higher proportions of metals — elements heavier than hydrogen and helium are curiously known as metals in astronomy — than stars found in similar clusters. A handful of these high-metallicity stars are also variable stars, meaning that their brightness fluctuates over time. NGC 6496 hosts a selection of long-period variables — giant pulsating stars whose brightness can take up to, and even over, a thousand days to change — and short-period eclipsing binaries, which dim when eclipsed by a stellar companion. The nature of the variability of these stars can reveal important information about their mass, radius, luminosity, temperature, composition, and evolution, providing astronomers with measurements that would be difficult or even impossible to obtain through other methods. NGC 6496 was discovered in 1826 by Scottish astronomer James Dunlop. The cluster resides at about 35,000 light-years away in the southern constellation of Scorpius (The Scorpion). Image credit: ESA/Hubble & NASA, Acknowledgement: Judy Schmidt Text credit: European Space Agency Read more: go.nasa.gov/1U2wqGW

[Progress in research of relationship between heavy metal exposure and cardiovascular disease].

PubMed

Lu, F; Zhao, F; Cai, J Y; Liu, L; Shi, X M

2018-01-10

Heavy metal is one of pollutants existed widely in the environment, its relationship with cardiovascular disease has attracted more and more attention. In this review, the concentrations of heavy metals, including lead, cadium and asenic, in the body from several national surveillance networks and the epidemiological studies on the effects of the exposure of three heavy metals on cardiovascular system were summarized. It is suggested to strengthen nationwide surveillance for body concentrations of heavy metals in general population in order to provide baseline data for quantitative evaluation of the risk of heavy metal exposure on cardiovascular disease.

Distribution and risk assessment of heavy metals in sewage sludge after ozonation.

PubMed

Zhang, Jian; Tian, Yu; Zhang, Jun; Li, Ning; Kong, Lingchao; Yu, Ming; Zuo, Wei

2017-02-01

In this paper, transformation of chemical forms of heavy metals (Cu, Zn, Ni, Pb, Cr, Cd, Mn, and Mg) in sewage sludge (SS) during ozonation was investigated. Meanwhile, the risk of heavy metals to environment in ozonated sludge (OS) and SS was estimated according to risk assessment code (RAC). The residual rates of heavy metals were over 72.8 %, which demonstrated that the heavy metals in SS were mainly existed in the OS after ozonation. The results indicated that the ozonation had an effect on the redistribution of heavy metals. The comparisons of the RAC between OS and SS indicated that the environmental risk of heavy metals in OS was aggravated compared to SS, except for Mg. Consequently, it was suggested that the OS should be pretreated before application.

Heavy metal accumulation and source analysis in greenhouse soils of Wuwei District, Gansu Province, China.

PubMed

Bai, L Y; Zeng, X B; Su, S M; Duan, R; Wang, Y N; Gao, X

2015-04-01

Greenhouse soils and arable (wheat field) soil samples were collected to identify the effects of greenhouse cultivation on the accumulation of six heavy metals (Cd, Cu, Zn, Pb, Cr, and Ni) and to evaluate the likely sources responsible for heavy metal accumulation in the irrigated desert soils of Wuwei District, China. The results indicated that the mean concentrations of Cd, Cu, Zn, Pb, Cr, and Ni were 0.421, 33.85, 85.31, 20.76, 53.12, and 28.59 mg kg(-1), respectively. The concentrations of Cd, Cu, and Zn in greenhouse soils were 60, 23, and 14% higher than those in arable soils and 263, 40, and 25% higher than background concentrations of natural soils in the study area, respectively. These results indicated that Cd, Cu, and Zn accumulation occurred in the greenhouse soils, and Cd was the most problematically accumulated heavy metal, followed by Cu and Zn. There was a significant positive correlation between the concentrations of Cd, Cu, and Zn in greenhouse soils and the number of years under cultivation (P < 0.05). Greenhouse cultivation had little impact on the accumulation of Cr, Ni, or Pb. Correlation analysis and principal component analysis suggested that the accumulation of Cd, Cu, and Zn in greenhouse soils resulted mainly from fertilizer applications. Our results indicated that the excessive and long-term use of fertilizers and livestock manures with high heavy metal levels leads to the accumulation of heavy metals in soils. Therefore, rational fertilization programs and reductions in the concentrations of heavy metals in both fertilizers and manure must be recommended to maintain a safe concentration of heavy metals in greenhouse soils.

Magnetic susceptibility as an indicator of heavy metal contamination in compost.

PubMed

Paradelo, Remigio; Moldes, Ana Belén; Barral, María Teresa

2009-02-01

One of the main restrictions to the agronomic use of compost is the excess of heavy metals, which are often present due to inadequate separation of biodegradable fractions from non-degradable or inert materials. Magnetic susceptibility (MS) measurements are a simple technique that has been reported as a useful tool for assessing anthropogenic pollution, especially heavy metal pollution on soil and sediment samples. The close relationship of MS with heavy metal contamination has been proved by combined analyses of chemical and magnetic data. In this study, the MS and total heavy metal concentrations of eight composts from different origins were determined; all composts were passed under a magnet to remove the magnetic material, and total heavy metals were determined again. In our work, high correlations were found between magnetic susceptibility and total Cd, Zn, Pb, Cr and Ni, thus confirming the applicability of MS measurement as a proxy for heavy metal contamination in compost quality assessments. The application of a magnet over the composts reduced the MS as well as the heavy metal content, the reduction of Fe and MS being the most significantly correlated. Thus, the inclusion of an additional magnetic separation step in the post-process compost finishing could be envisaged.

Comparison of the multifractal characteristics of heavy metals in soils within two areas of contrasting economic activities in China

NASA Astrophysics Data System (ADS)

Li, Xiaohui; Li, Xiangling; Yuan, Feng; Jowitt, Simon M.; Zhou, Taofa; Yang, Kui; Zhou, Jie; Hu, Xunyu; Li, Yang

2016-09-01

Industrial and agricultural activities can generate heavy metal pollution that can cause a number of negative environmental and health impacts. This means that evaluating heavy metal pollution and identifying the sources of these pollutants, especially in urban or developed areas, is an important first step in mitigating the effects of these contaminating but necessary economic activities. Here, we present the results of a heavy metal (Cu, Pb, Zn, Cd, As, and Hg) soil geochemical survey in Hefei city. We used a multifractal spectral technique to identify and compare the multifractality of heavy metal concentrations of soils within the industrial Daxing and agricultural Yicheng areas. This paper uses three multifractal parameters (Δα, Δf(α), and τ''(1)) to indicate the overall amount of multifractality within the soil geochemical data. The results show all of the elements barring Hg have larger Δα, Δf(α), and τ''(1) values in the Daxing area compared to the Yicheng area. The degree of multifractality suggests that the differing economic activities in Daxing and Yicheng generate very different heavy metal pollution loads. In addition, the industrial Daxing area contains significant Pb and Cd soil contamination, whereas Hg is the main heavy metal present in soils within the Yicheng area, indicating that differing clean-up procedures and approaches to remediating these polluted areas are needed. The results also indicate that multifractal modelling and the associated generation of multifractal parameters can be a useful approach in the evaluation of heavy metal pollution in soils.

Oil palm biomass as an adsorbent for heavy metals.

PubMed

Vakili, Mohammadtaghi; Rafatullah, Mohd; Ibrahim, Mahamad Hakimi; Abdullah, Ahmad Zuhairi; Salamatinia, Babak; Gholami, Zahra

2014-01-01

Many industries discharge untreated wastewater into the environment. Heavy metals from many industrial processes end up as hazardous pollutants of wastewaters.Heavy metal pollution has increased in recent decades and there is a growing concern for the public health risk they may pose. To remove heavy metal ions from polluted waste streams, adsorption processes are among the most common and effective treatment methods. The adsorbents that are used to remove heavy metal ions from aqueous media have both advantages and disadvantages. Cost and effectiveness are two of the most prominent criteria for choosing adsorbents. Because cost is so important, great effort has been extended to study and find effective lower cost adsorbents.One class of adsorbents that is gaining considerable attention is agricultural wastes. Among many alternatives, palm oil biomasses have shown promise as effective adsorbents for removing heavy metals from wastewater. The palm oil industry has rapidly expanded in recent years, and a large amount of palm oil biomass is available. This biomass is a low-cost agricultural waste that exhibits, either in its raw form or after being processed, the potential for eliminating heavy metal ions from wastewater. In this article, we provide background information on oil palm biomass and describe studies that indicate its potential as an alternative adsorbent for removing heavy metal ions from wastewater. From having reviewed the cogent literature on this topic we are encouraged that low-cost oil-palm-related adsorbents have already demonstrated outstanding removal capabilities for various pollutants.Because cost is so important to those who choose to clean waste streams by using adsorbents, the use of cheap sources of unconventional adsorbents is increasingly being investigated. An adsorbent is considered to be inexpensive when it is readily available, is environmentally friendly, is cost-effective and be effectively used in economical processes. The

Characteristics of heavy metal pollution on roadside soil along highway

NASA Astrophysics Data System (ADS)

Zheng, Chaocheng

2017-10-01

Highway traffic is the main source of heavy metal pollution. Due to limited cropland, it is very common to plant crops along the highways. So, in view of agricultural products safety, heavy metal pollution by highway traffic to soils along highway is widely concerned. Therefore, to study distribution traits, accumulative laws and influence factors of heavy metals in agricultural soils could provide scientific evidence and theoretical basis for environmental protection along express way.

Biosorption of heavy metals by obligate halophilic fungi.

PubMed

Bano, Amna; Hussain, Javaid; Akbar, Ali; Mehmood, Khalid; Anwar, Muhammad; Hasni, Muhammad Sharif; Ullah, Sami; Sajid, Sumbal; Ali, Imran

2018-05-01

The presence of heavy metals in the environment poses a serious threat to human health. Remediation of this problem using microorganisms has been widely researched to find a sustainable solution. Obligate halophilic fungi comprising Aspergillus flavus, Aspergillus gracilis, Aspergillus penicillioides (sp. 1), Aspergillus penicillioides (sp. 2), Aspergillus restrictus and Sterigmatomyces halophilus were used for the biosorption of cadmium, copper, ferrous, manganese, lead and zinc. The metals were supplemented as salts in potato dextrose broth for the growth of obligate halophilic fungi and incubated for 14 days. The supernatant and biomass were obtained by the acid digestion method. The biosorption was screened by atomic absorption spectroscopy. All tested fungi showed moderate to high adsorption of heavy metals, amongst which A. flavus and S. halophilus showed the best average adsorption of all heavy metals studied, with an average of 86 and 83%, respectively. On average, Fe and Zn are best removed from the liquid media of obligate halophilic fungi, with an average of 85 and 84%, respectively. This pioneering study of biosorption by obligate halophilic fungi using inexpensive media in stagnant conditions provides a cost-effective environmental solution for the removal of heavy metals. Copyright © 2018 Elsevier Ltd. All rights reserved.

Heavy metals from Kueishantao shallow-sea hydrothermal vents, offshore northeast Taiwan

NASA Astrophysics Data System (ADS)

Chen, Xue-Gang; Lyu, Shuang-Shuang; Garbe-Schönberg, Dieter; Lebrato, Mario; Li, Xiaohu; Zhang, Hai-Yan; Zhang, Ping-Ping; Chen, Chen-Tung Arthur; Ye, Ying

2018-04-01

Shallow water hydrothermal vents are a source of heavy metals leading to their accumulation in marine organisms that manage to live under extreme environmental conditions. This is the case at Kueishantao (KST) shallow-sea vents system offshore northeast Taiwan, where the heavy metal distribution in vent fluids and ambient seawater is poorly understood. This shallow vent is an excellent natural laboratory to understand how heavy and volatile metals behave in the nearby water column and ecosystem. Here, we investigated the submarine venting of heavy metals from KST field and its impact on ambient surface seawater. The total heavy metal concentrations in the vent fluids and vertical plumes were 1-3 orders of magnitude higher than the overlying seawater values. When compared with deep-sea hydrothermal systems, the estimated KST end-member fluids exhibited much lower concentrations of transition metals (e.g., Fe and Mn) but comparable concentrations of toxic metals such as Pb and As. This may be attributed to the lower temperature of the KST reaction zone and transporting fluids. Most of the heavy metals (Fe, Mn, As, Y, and Ba) in the plumes and seawater mainly originated from hydrothermal venting, while Cd and Pb were largely contributed by external sources such as contaminated waters (anthropogenic origin). The spatial distribution of heavy metals in the surface seawater indicated that seafloor venting impacts ambient seawater. The measurable influence of KST hydrothermal activity, however, was quite localized and limited to an area of < 1 km2. The estimated annual fluxes of heavy metals emanating from the yellow KST hydrothermal vent were: 430-2600 kg Fe, 24-145 kg Mn, 5-32 kg Ba, 10-60 kg As, 0.3-1.9 kg Cd, and 2-10 kg Pb. This study provides important data on heavy metals from a shallow-sea hydrothermal field, and it helps to better understand the environmental impact of submarine shallow hydrothermal venting.

Heavy metals accumulation affects bone microarchitecture in osteoporotic patients.

PubMed

Scimeca, Manuel; Feola, Maurizio; Romano, Lorenzo; Rao, Cecilia; Gasbarra, Elena; Bonanno, Elena; Brandi, Maria Luisa; Tarantino, Umberto

2017-04-01

Bone metabolism is affected by mechanical, genetic, and environmental factors and plays a major role in osteoporosis. Nevertheless, the influence of environmental pollution on the occurrence of osteoporosis is still unclear and controversial. In this context, heavy metals are the most important pollutants capable to affect bone mass. The aim of this study was to investigate whether heavy metals accumulation in bone tissues could be related to the altered bone metabolism and architecture of osteoporotic patients. To this end, we analyzed 25 bone head biopsies osteoporotic patients and 25 bone head biopsies of osteoarthritic patients. Moreover we enrolled 15 patients underwent hip arthroplasty for high-energy hip fracture or osteonecrosis of the femoral head as a control group. Bone head biopsies were studied by BioQuant-osteo software, scanning electron microscopy and Energy Dispersive X-ray microanalysis. We found a prevalence of lead, cadmium and chromium accumulation in osteoporotic patients. Noteworthy, high levels of sclerostin, detected by immunohistochemistry, correlate with the accumulation of heavy metal found in the bone of osteoporotic patients, suggesting a molecular link between heavy metal accumulation and bone metabolism impairment. In conclusion, the presence of heavy metals into bone shed new light on the comprehension of the pathogenesis of osteoporosis since these elements could play a non redundant role in the development of osteoporosis at cellular/molecular and epigenetic level. Nevertheless, in vivo and in vitro studies need to better elucidate the molecular mechanism in which heavy metals can participate to osteoporosis. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1333-1342, 2017. © 2016 Wiley Periodicals, Inc.

Inputs of heavy metals due to agrochemical use in tobacco fields in Brazil's Southern Region.

PubMed

Zoffoli, Hugo José Oliveira; do Amaral-Sobrinho, Nelson Moura Brasil; Zonta, Everaldo; Luisi, Marcus Vinícius; Marcon, Gracioso; Tolón-Becerra, Alfredo

2013-03-01

Only a few studies have assessed the joint incorporation of heavy metals into agricultural systems based on the range of agrochemicals used on a specific agricultural crop. This study was conducted to assess the heavy metals input through application of the main agrochemicals used in Brazilian tobacco fields. A total of 56 samples of different batches of 5 fertilizers, 3 substrates, 8 insecticides, 3 fungicides, 2 herbicides, and 1 growth regulator commonly used in the cultivation of tobacco in Brazil's Southern Region were collected from 3 warehouses located in the States of Rio Grande do Sul, Santa Catarina, and Paraná. The total As, Cd, Co, Cr, Cu, Hg, Fe, Mn, Ni, Pb, and Zn content of the samples was then determined and compared with the regulations of different countries and information found in the available literature. The fertilizers were identified as the primary source of heavy metals among the agrochemicals used. Application of pesticides directly to the shoots of tobacco plants contributed very little to the supply of heavy metals. The agrochemicals used in Brazilian tobacco fields provide lower inputs of the main heavy metals that are nonessential for plants than those registered in the international literature for the majority of crop fields in different regions of the world.

Atmospheric heavy metals and Arsenic in China: Situation, sources and control policies

NASA Astrophysics Data System (ADS)

Duan, Jingchun; Tan, Jihua

2013-08-01

In recent years, heavy metal pollution accidents were reported frequently in China. The atmospheric heavy metal pollution is drawing all aspects of attention. This paper summarizes the recent research results from our studies and previous studies in recent years in China. The level, temporal variation, seasonal variation and size distribution of the heavy metals of atmospheric Lead(Pb), Vanadium(V), Manganese(Mn), Nickel(Ni), Chromium(Cr), Cadmium(Cd), Copper(Cu), Zinc(Zn) and Arsenic(As) were characterized in China. The emission characteristics and sources of atmospheric heavy metals and As in China were reviewed. Coal burning, iron and steel industry and vehicle emission are important sources in China. Control policies and effects in China were reviewed including emission standards, ambient air quality standards, phase out of leaded gasoline and so on, and further works for atmospheric heavy metals control were suggested. The comprehensive heavy metals pollution control measures and suggestions were put forward based on the summarization of the development and experience of the atmospheric heavy metal pollution control abroad.

Multivariate-Statistical Assessment of Heavy Metals for Agricultural Soils in Northern China

PubMed Central

Yang, Pingguo; Yang, Miao; Mao, Renzhao; Shao, Hongbo

2014-01-01

The study evaluated eight heavy metals content and soil pollution from agricultural soils in northern China. Multivariate and geostatistical analysis approaches were used to determine the anthropogenic and natural contribution of soil heavy metal concentrations. Single pollution index and integrated pollution index could be used to evaluate soil heavy metal risk. The results show that the first factor explains 27.3% of the eight soil heavy metals with strong positive loadings on Cu, Zn, and Cd, which indicates that Cu, Zn, and Cd are associated with and controlled by anthropic activities. The average value of heavy metal is lower than the second grade standard values of soil environmental quality standards in China. Single pollution index is lower than 1, and the Nemerow integrated pollution index is 0.305, which means that study area has not been polluted. The semivariograms of soil heavy metal single pollution index fitted spherical and exponential models. The variable ratio of single pollution index showed moderately spatial dependence. Heavy metal contents showed relative safety in the study area. PMID:24892058

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.

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.

Heavy metal partitioning of suspended particulate matter-water and sediment-water in the Yangtze Estuary.

PubMed

Feng, Chenghong; Guo, Xiaoyu; Yin, Su; Tian, Chenhao; Li, Yangyang; Shen, Zhenyao

2017-10-01

The partitioning of ten heavy metals (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, and Zn) between the water, suspended particulate matter (SPM), and sediments in seven channel sections during three hydrologic seasons in the Yangtze Estuary was comprehensively investigated. Special attention was paid to the role of tides, influential factors (concentrations of SPM and dissolved organic carbon, and particle size), and heavy metal speciation. The SPM-water and sediment-water partition coefficients (K p ) of the heavy metals exhibited similar changes along the channel sections, though the former were larger throughout the estuary. Because of the higher salinity, the K p values of most of the metals were higher in the north branch than in the south branch. The K p values of Cd, Co, and As generally decreased from the wet season to the dry season. Both the diagonal line method and paired samples t-test showed that no specific phase transfer of heavy metals existed during the flood and ebb tides, but the sediment-water K p was more concentrated for the diagonal line method, owing to the relatively smaller tidal influences on the sediment. The partition coefficients (especially the K p for SPM-water) had negative correlations with the dissolved organic carbon (DOC) but positive correlations were noted with the particle size for most of the heavy metals in sediment. Two types of significant correlations were observed between K p and metal speciation (i.e., exchangeable, carbonate, reducible, organic, and residual fractions), which can be used to identify the dominant phase-partition mechanisms (e.g., adsorption or desorption) of heavy metals. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bacterial mediated alleviation of heavy metal stress and decreased accumulation of metals in plant tissues: Mechanisms and future prospects.

PubMed

Etesami, Hassan

2018-01-01

Heavy metal pollution of agricultural soils is one of main concerns causing some of the different ecological and environmental problems. Excess accumulation of these metals in soil has changed microbial community (e.g., structure, function, and diversity), deteriorated soil, decreased the growth and yield of plant, and entered into the food chain. Plants' tolerance to heavy metal stress needs to be improved in order to allow growth of crops with minimum or no accumulation of heavy metals in edible parts of plant that satisfy safe food demands for the world's rapidly increasing population. It is well known that PGPRs (plant growth-promoting rhizobacteria) enhance crop productivity and plant resistance to heavy metal stress. Many recent reports describe the application of heavy metal resistant-PGPRs to enhance agricultural yields without accumulation of metal in plant tissues. This review provides information about the mechanisms possessed by heavy metal resistant-PGPRs that ameliorate heavy metal stress to plants and decrease the accumulation of these metals in plant, and finally gives some perspectives for research on these bacteria in agriculture in the future. Copyright © 2017 Elsevier Inc. All rights reserved.

Abundance and diversity of Archaea in heavy-metal-contaminated soils.

PubMed

Sandaa, R A; Enger, O; Torsvik, V

1999-08-01

The impact of heavy-metal contamination on archaean communities was studied in soils amended with sewage sludge contaminated with heavy metals to varying extents. Fluorescent in situ hybridization showed a decrease in the percentage of Archaea from 1.3% +/- 0.3% of 4', 6-diamidino-2-phenylindole-stained cells in untreated soil to below the detection limit in soils amended with heavy metals. A comparison of the archaean communities of the different plots by denaturing gradient gel electrophoresis revealed differences in the structure of the archaean communities in soils with increasing heavy-metal contamination. Analysis of cloned 16S ribosomal DNA showed close similarities to a unique and globally distributed lineage of the kingdom Crenarchaeota that is phylogenetically distinct from currently characterized crenarchaeotal species.

Heavy Metal Pollution, Fractionation, and Potential Ecological Risks in Sediments from Lake Chaohu (Eastern China) and the Surrounding Rivers

PubMed Central

Zhang, Lei; Liao, Qianjiahua; Shao, Shiguang; Zhang, Nan; Shen, Qiushi; Liu, Cheng

2015-01-01

Heavy metal (Cr, Ni, Cu, Zn, Cd, and Pb) pollution, fractionation, and ecological risks in the sediments of Lake Chaohu (Eastern China), its eleven inflowing rivers and its only outflowing river were studied. An improved BCR (proposed by the European Community Bureau of Reference) sequential extraction procedure was applied to fractionate heavy metals within sediments, a geoaccumulation index was used to assess the extent of heavy metal pollution, and a risk assessment code was applied to evaluate potential ecological risks. Heavy metals in the Shuangqiao and Nanfei Rivers were generally higher than the other studied sites. Of the three Lake Chaohu sites, the highest concentrations were identified in western Chaohu. Heavy metal pollution and ecological risks in the lake’s only outflowing river were similar to those in the eastern region of the lake, to which the river is connected. Heavy metal concentrations occurred in the following order: Cd > Zn > Cu > Pb ≈ Ni ≈ Cr. Cr, Ni, and Cu made up the largest proportion of the residual fraction, while Cd was the most prominent metal in the exchangeable and carbonate-included fraction. Cd posed the greatest potential ecological risk; the heavy metals generally posed risks in the following order: Cd > Zn > Cu > Ni > Pb > Cr. PMID:26561822

Feasibility analysis of EDXRF method to detect heavy metal pollution in ecological environment

NASA Astrophysics Data System (ADS)

Hao, Zhixu; Qin, Xulei

2018-02-01

The change of heavy metal content in water environment, soil and plant can reflect the change of heavy metal pollution in ecological environment, and it is important to monitor the trend of heavy metal pollution in eco-environment by using water environment, soil and heavy metal content in plant. However, the content of heavy metals in nature is very low, the background elements of water environment, soil and plant samples are complex, and there are many interfering factors in the EDXRF system that will affect the spectral analysis results and reduce the detection accuracy. Through the contrastive analysis of several heavy metal elements detection methods, it is concluded that the EDXRF method is superior to other chemical methods in testing accuracy and method feasibility when the heavy metal pollution in soil is tested in ecological environment.

[History of heavy metal pollution from tidal flat in Haizhou Bay].

PubMed

Zhang, Rui; Zhang, Fan; Liu, Fu-Cheng; Yin, Fu-Jun; Ding, Ying-Jun; Gao, Jin-Rong; Chen, Jing; Shao, Wei

2013-03-01

Coastal zone could be considered as an important sink of regional source to sink and preserve historical records of environmental evolution. Four sediment cores, collected from tidal flat at Haizhou Bay near Lianyungang City, were examined for concentrations of heavy metals including Cd, Cr, Cu, Mn, Pb and Zn in core sediments to investigate the historical input of trace metals. In addition, sediment rates of cores LH3 and LH4 were determined based on radionuclide 210Pb. The results showed that grain size control effect was not the main factor that influenced the distribution of heavy metals. Heavy metals concentrations in the surface sediments were higher than these regional background values. Furthermore, Al element as a proxy of grain size was selected for normalization and calculation of metal enrichment factor (EF) and anthropogenic heavy metal fluxes. The results revealed that heavy metals in tidal flats were continuously enriched in the past decades, meanwhile, tidal flats have been significantly subjected to contaminations due to anthropogenic activities. Moreover, the depth profiles of heavy metals fluxes correspond to scenario of social-economy development of Lianyungang, which is an important urban area near Haizhou Bay. From 1950s to 2005, anthropogenic fluxes of metals increased with fluctuations, whereas, since 2005 anthropogenic fluxes declined, which may be correlated to the adjustment of industrial structure as well as the strengthened environmental regulation.

Particle size distribution and characteristics of heavy metals in road-deposited sediments from Beijing Olympic Park.

PubMed

Li, Haiyan; Shi, Anbang; Zhang, Xiaoran

2015-06-01

Due to rapid urbanization and industrialization, heavy metals in road-deposited sediments (RDSs) of parks are emitted into the terrestrial, atmospheric, and water environment, and have a severe impact on residents' and tourists' health. To identify the distribution and characteristic of heavy metals in RDS and to assess the road environmental quality in Chinese parks, samples were collected from Beijing Olympic Park in the present study. The results indicated that particles with small grain size (<150 μm) were the dominant fraction. The length of dry period was one of the main factors affecting the particle size distribution, as indicated by the variation of size fraction with the increase of dry days. The amount of heavy metal (i.e., Cu, Zn, Pb and Cd) content was the largest in particles with small size (<150 μm) among all samples. Specifically, the percentage of Cu, Zn, Pb and Cd in these particles was 74.7%, 55.5%, 56.6% and 71.3%, respectively. Heavy metals adsorbed in sediments may mainly be contributed by road traffic emissions. The contamination levels of Pb and Cd were higher than Cu and Zn on the basis of the mean heavy metal contents. Specifically, the geoaccumulation index (Igeo) decreased in the order: Cd>Pb>Cu>Zn. This study analyzed the mobility of heavy metals in sediments using partial sequential extraction with the Tessier procedure. The results revealed that the apparent mobility and potential metal bioavailability of heavy metals in the sediments, based on the exchangeable and carbonate fractions, decreased in the order: Cd>Zn≈Pb>Cu. Copyright © 2015. Published by Elsevier B.V.

The effects of the Qinghai-Tibet railway on heavy metals enrichment in soils.

PubMed

Zhang, Hua; Wang, Zhaofeng; Zhang, Yili; Hu, Zhongjun

2012-11-15

The impact of land transportation on local soil environments is an important topic in environmental and ecological sciences. The rapid development of transportation infrastructure lends increasing importance to studies that identify and evaluate related heavy metal pollution. This paper discusses the effects of railways on soil heavy metal enrichments in the Tibetan plateau. At a representative area along the Haergai-Delingha railway, lead, cadmium, copper, zinc, chromium, nickel, cobalt, and vanadium were measured in 127 topsoil samples (0-10 cm depth). The results indicate that railway transport has a significant effect on the concentration of Zn, Cd and Pb in the soil, with levels of enrichment ranging from no pollution to significant pollution. The affected area was within 20 m of the railway. The soil at Delingha was the most contaminated soil with heavy metals, and the enrichment level of Cd in the soil was the highest along the Qinghai-Tibet railway. The horizontal distributions of the three heavy metals present different characteristics at different sampling sites, which may be due to discrepancies in terrain and vegetation types. Alkaline soils and guardrails along the railway might reduce the effect of soil pollution on local people and animals. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

Soil heavy metal pollution and risk assessment in Shenyang industrial district, Northeast China.

PubMed

Jiao, Xudong; Teng, Yanguo; Zhan, Yanhong; Wu, Jin; Lin, Xueyu

2015-01-01

To investigate the soil heavy metal pollution characteristics and ecological risk factors, 42 samples and six typical soil profiles were collected from the Shenyang industrial district in northeast China and were analyzed for contents of titanium (Ti), copper (Cu), lead (Pb), zinc (Zn), cobalt (Co), nickel (Ni), chromium (Cr) and arsenic (As). Through statistical analysis, it was found that the mean concentrations were higher than their background values (Ti = 4.77>3.8g/kg, Cu = 33.75>22.6 mg/kg, Pb = 45.95>26 mg/kg, Zn = 81.54>74.2 mg/kg, Co = 12.91>12.7 mg/kg, Ni = 32.26>26.9 mg/kg, Cr = 83.36>61 mg/kg and As = 13.69>11.2 mg/kg) but did not exceed their corresponding pollution limits for the Chinese Environmental Quality Standard for Soils (State Environmental Protection Administration of China, 1995). There were contamination hotspots that may be caused by human activities such as smelting plants and sewage irrigation. The Enrichment Factor and Ecological Risk Index were used to identify the anthropogenic contamination and ecological risks of heavy metals. Soil in the study area could be considered lightly or partially polluted by heavy metals. According to clustering analysis, distinct groups of heavy metals were discriminated between natural or anthropogenic sources.

The influence of bioavailable heavy metals and microbial parameters of soil on the metal accumulation in rice grain.

PubMed

Xiao, Ling; Guan, Dongsheng; Peart, M R; Chen, Yujuan; Li, Qiqi; Dai, Jun

2017-10-01

A field-based study was undertaken to analyze the effects of soil bioavailable heavy metals determined by a sequential extraction procedure, and soil microbial parameters on the heavy metal accumulation in rice grain. The results showed that Cd, Cr, Cu, Ni, Pb and Zn concentrations in rice grain decreases by 65.9%, 78.9%, 32.6%, 80.5%, 61.0% and 15.7%, respectively in the sites 3 (far-away), compared with those in sites 1 (close-to). Redundancy analysis (RDA) indicated that soil catalase activity, the MBC/MBN ratio, along with bioavailable Cd, Cr and Ni could explain 68.9% of the total eigenvalue, indicating that these parameters have a great impact on the heavy metal accumulation in rice grain. The soil bioavailable heavy metals have a dominant impact on their accumulation in rice grain, with a variance contribution of 60.1%, while the MBC/MBN has a regulatory effect, with a variance contribution of 4.1%. Stepwise regression analysis showed that the MBC/MBN, urease and catalase activities are the key microbial parameters that affect the heavy metal accumulation in rice by influencing the soil bioavailable heavy metals or the translocation of heavy metals in rice. RDA showed an interactive effect between Cu, Pb and Zn in rice grain and the soil bioavailable Cd, Cr and Ni. The heavy metals in rice grain, with the exception of Pb, could be predicted by their respective soil bioavailable heavy metals. The results suggested that Pb accumulation in rice grain was mainly influenced by the multi-metal interactive effects, and less affected by soil bioavailable Pb. Copyright © 2017 Elsevier Ltd. All rights reserved.

Distribution and source analysis of heavy metal pollutants in sediments of a rapid developing urban river system.

PubMed

Xia, Fang; Qu, Liyin; Wang, Ting; Luo, Lili; Chen, Han; Dahlgren, Randy A; Zhang, Minghua; Mei, Kun; Huang, Hong

2018-09-01

Heavy metal pollution of aquatic environments in rapidly developing industrial regions is of considerable global concern due to its potential to cause serious harm to aquatic ecosystems and human health. This study assessed heavy metal contamination of sediments in a highly industrialized urban watershed of eastern China containing several historically unregulated manufacturing enterprises. Total concentrations and solid-phase fractionation of Cu, Zn, Pb, Cr and Cd were investigated for 39 river sediments using multivariate statistical analysis and geographically weighted regression (GWR) methods to quantitatively examine the relationship between land use and heavy metal pollution at the watershed scale. Results showed distinct spatial patterns of heavy metal contamination within the watershed, such as higher concentrations of Zn, Pb and Cd in the southwest and higher Cu concentration in the east, indicating links to specific pollution sources within the watershed. Correlation and PCA analyses revealed that Zn, Pb and Cd were dominantly contributed by anthropogenic activities; Cu originated from both industrial and agricultural sources; and Cr has been altered by recent pollution control strategies. The GWR model indicated that several heavy metal fractions were strongly correlated with industrial land proportion and this correlation varied with the level of industrialization as demonstrated by variations in local GWR R 2 values. This study provides important information for assessing heavy metal contaminated areas, identifying heavy metal pollutant sources, and developing regional-scale remediation strategies. Copyright © 2018 Elsevier Ltd. All rights reserved.

Two-stage anaerobic digestion enables heavy metal removal.

PubMed

Selling, Robert; Håkansson, Torbjörn; Björnsson, Lovisa

2008-01-01

To fully exploit the environmental benefits of the biogas process, the digestate should be recycled as biofertiliser to agriculture. This practice can however be jeopardized by the presence of unwanted compounds such as heavy metals in the digestate. By using two-stage digestion, where the first stage includes hydrolysis/acidification and liquefaction of the substrate, heavy metals can be transferred to the leachate. From the leachate, metals can then be removed by adsorption. In this study, up to 70% of the Ni, 40% of the Zn and 25% of the Cd present in maize was removed when the leachate from hydrolysis was circulated over a macroporous polyacrylamide column for 6 days. For Cu and Pb, the mobilization in the hydrolytic stage was lower which resulted in a low removal. A more efficient two-stage process with improved substrate hydrolysis would give lower pH and/or longer periods with low pH in the hydrolytic stage. This is likely to increase metal mobilisation, and would open up for an excellent opportunity of heavy metal removal.

Adsorption of heavy metals by road deposited solids.

PubMed

Gunawardana, Chandima; Goonetilleke, Ashantha; Egodawatta, Prasanna

2013-01-01

The research study discussed in the paper investigated the adsorption/desorption behaviour of heavy metals commonly deposited on urban road surfaces, namely, Zn, Cu, Cr and Pb, for different particle size ranges of solids. The study outcomes, based on field studies and batch experiments, confirmed that road deposited solids particles contain a significantly high amount of vacant charge sites with the potential to adsorb additional heavy metals. Kinetic studies and adsorption experiments indicated that Cr is the most preferred metal element to associate with solids due to the relatively high electronegativity and high charge density of trivalent cation (Cr(3+)). However, the relatively low availability of Cr in the urban road environment could influence this behaviour. Comparing total adsorbed metals present in solids particles, it was found that Zn has the highest capacity for adsorption to solids. Desorption experiments confirmed that a low concentration of Cu, Cr and Pb in solids was present in water-soluble and exchangeable form, whilst a significant fraction of adsorbed Zn has a high likelihood of being released back into solution. Among heavy metals, Zn is considered to be the most commonly available metal among road surface pollutants.

Identification of Heavy Metal Pollution Derived From Traffic in Roadside Soil Using Magnetic Susceptibility.

PubMed

Yang, Pingguo; Ge, Jing; Yang, Miao

2017-06-01

The study integrates surface and vertical distribution of magnetic susceptibility and heavy metal contents (Pb, Cu, Zn and Fe) to characterize the signature of vehicle pollutants in roadside soils at Linfen city, China. Sites with reforestation and without vegetation cover were investigated. The results showed that magnetic susceptibility and heavy metal contents were higher at the roadside without trees than in the reforest belt. The variations of magnetic susceptibility and heavy metal contents decreased both with distance and with depth. The maximum value was observed at 5-10 m away from the roadside edge. The vertical distribution in soil revealed accumulation of pollutants in 0-5 cm topsoils. The average contents were higher than the background values and in the order Fe (107.21 g kg -1 ), Zn (99.72 mg kg -1 ), Pb (90.99 mg kg -1 ), Cu (36.14 mg kg -1 ). Coarse multi domain grains were identified as the dominating magnetic particles. Multivariate statistical and SEM/EDX analyses suggested that the heavy metals derived from traffic sources. Trees act as efficient receptors and green barrier, which can reduce vehicle derived pollution.

Simultaneous hyperaccumulation of multiple heavy metals by Helianthus annuus grown in a contaminated sandy-loam soil.

PubMed

Cutright, Teresa; Gunda, Nagaraju; Kurt, Firat

2010-08-01

Phytoremediation is a promising means for the treatment of contamination arising from heavy metal spills. Although several species have been identified as hyperaccumulators, most of the studies were performed with only one heavy metal. Experiments were conducted with two cultivars of H. annuus exposed to different combinations of metal contamination (30 mg/kg Cd, Cr, Ni, As, and/or Fe). Cultivar efficiency was based on total metal uptake, as well as translocation and selectivity of each metal. The results for each cultivar were also compared after 0.1 g/kg or 0.3 g/kg EDTA was added to enhance metal bioavailability. The key finding was that H. annuus achieved hyperaccumulator status for multiple metals simultaneously: Cd, Cr, and As.

Distribution of heavy metals from flue gas in algal bioreactor

NASA Astrophysics Data System (ADS)

Napan, Katerine

Flue gas from coal-fired power plants is a major source of CO2 to the atmosphere. Microalgae can use this enriched form of CO2 as carbon source and in turn the biomass can be used to produce food, feed, fertilizer and biofuels. However, along with CO2, coal-based flue gas will inevitably introduce heavy metals, which have a high affinity to bind algal cells, could be toxic to the organisms and if transferred to the products could limit their uses. This study seeks to address the distribution and impact of heavy metals present in flue gas on microalgae production systems. To comprehend its effects, algae Scenedesmus obliquus was grown in batch reactors in a multimetal system. Ten heavy metals (Cu, Co, Zn, Pb, As, Se, Cr, Hg, Ni and Cd) were selected and were evaluated at four concentrations (1X, 2X, 5X and 10X). Results show that most heavy metals accumulated mainly in biomass and were found in very low concentrations in media. Hg was shown to be lost from the culture, with low amounts present in the biomass. An upper limit for As uptake was observed, suggesting its likelihood to build-up in the system during medium recycle. The As limited bioaccumulation was overcome by addition of sulfur to the algal medium. Heavy metal at 2X, 5X and 10X inhibited both growth and lipid production, while at the reference concentration both biomass and lipids yields were increased. Heavy metal concentrations in the medium and biomass were time dependent, and at the end of the cultivation most heavy metals in the supernatant solution complied with the recommendations for irrigation water, while biomass was below limits for cattle and poultry feed, fertilizer, plastic and paper. This research shows that bioremediation of CO2 and heavy metals in combination with energy production can be integrated, which is an environmentally friendly form of biotechnology.

Effect of Drying on Heavy Metal Fraction Distribution in Rice Paddy Soil

PubMed Central

Qi, Yanbing; Huang, Biao; Darilek, Jeremy Landon

2014-01-01

An understanding of how redox conditions affect soil heavy metal fractions in rice paddies is important due to its implications for heavy metal mobility and plant uptake. Rice paddy soil samples routinely undergo oxidation prior to heavy metal analysis. Fraction distribution of Cu, Pb, Ni, and Cd from paddy soil with a wide pH range was investigated. Samples were both dried according to standard protocols and also preserved under anaerobic conditions through the sampling and analysis process and heavy metals were then sequentially extracted for the exchangeable and carbonate bound fraction (acid soluble fraction), iron and manganese oxide bound fraction (reducible fraction), organic bound fraction (oxidizable fraction), and residual fraction. Fractions were affected by redox conditions across all pH ranges. Drying decreased reducible fraction of all heavy metals. Curesidual fraction, Pboxidizable fraction, Cdresidual fraction, and Niresidual fraction increased by 25%, 33%, 35%, and >60%, respectively. Pbresidual fraction, Niacid soluble fraction, and Cdoxidizable fraction decreased 33%, 25%, and 15%, respectively. Drying paddy soil prior to heavy metal analysis overestimated Pb and underestimated Cu, Ni, and Cd. In future studies, samples should be stored after injecting N2 gas to maintain the redox potential of soil prior to heavy metal analysis, and investigate the correlation between heavy metal fraction distribution under field conditions and air-dried samples. PMID:24823670

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

Human exposure risk to heavy metals through groundwater used for drinking in an intensively irrigated river delta

NASA Astrophysics Data System (ADS)

Vetrimurugan, E.; Brindha, K.; Elango, L.; Ndwandwe, Osman Muzi

2017-10-01

Drinking water containing heavy metals above the maximum permissible limits cause potential risk to human health. The aim of this study was to determine the groundwater suitability for drinking use based on heavy metal concentration and the associated human exposure risk in an intensively irrigated part of the Cauvery river basin, Tamil Nadu, India. Sixteen heavy metals analysed were in the order of dominance of chromium < zinc < copper < cadmium < cobalt < iron < aluminium < nickel < titanium < zirconium < boron < silver < manganese < lead < lithium < silicon in groundwater. Chromium and zinc were within permissible limits of the Bureau of Indian Standards for drinking water quality, and silver, lead and nickel were above limits in all the groundwater samples. In less than 50 % of the groundwater samples, aluminium, boron, cadmium, copper, iron and manganese exceeded their individual permissible limits. Heavy metal pollution index based on 11 heavy metals indicated that groundwater quality of this area is poor-to-unsuitable. Non-carcinogenic risk for humans due to ingestion of groundwater through drinking water pathway was very high for infants, children and adults. Silver, lead, nickel, cadmium and manganese largely contributed to the health hazard. Sources of heavy metals were identified to be geological and from human activities, i.e., application of fertilizers in agricultural fields, seawater intrusion due to intensive pumping for agriculture and wastewater from industries. Groundwater and surface water in this area pose large threat due to high levels of heavy metals, and it is necessary to avoid this water for drinking due to potential risk of health hazard. This study also demonstrated the application of HPI and human exposure hazard index to study the groundwater quality based on heavy metals' concentration.

What influences heavy metals accumulation in arctic lichen Cetrariella delisei in Svalbard?

NASA Astrophysics Data System (ADS)

Węgrzyn, Michał; Wietrzyk, Paulina; Lisowska, Maja; Klimek, Beata; Nicia, Paweł

2016-12-01

The main aim of this study was to identify variations in heavy metal concentrations in Cetrariella delisei along a transect from a High Arctic glacier forehead to the shoreline as well as determine the main environmental factors influencing the deposition of heavy metals in arctic lichens. The macrolichen Cetrariella delisei appears to be an interesting alternative to those lichen species used in the past (e.g. Flavocetraria nivalis, Cladonia sp.) for heavy metal biomonitoring purposes in the Arctic: it is widely distributed, easy to identify and reluctantly grazed by reindeer. Fieldwork was conducted in the summer of 2012 in the Kaffiøyra Plain, Oskar II Land, NW Spitsbergen. C. delisei and soil samples were collected from 5 localities. Concentrations of Cr, Mn, Ni, Cu, Zn, Pb, and Cd were measured in each sample. A bioaccumulation factor (BAF) was calculated for all the analyzed elements. The BAFs for Cu, Mn, and Ni showed a relatively low accumulation level in lichen thalli. On the other hand, the BAFs for Cr, Pb, and Zn, revealed an increased accumulation level in C. delisei. The Cd content in lichen is almost equal to its level in the soil. The statistical analyses covered three environmental factors: soil pH, substrate type and distance from the shoreline. The data were examined using the Kruskal-Wallis test, canonical correspondence analysis and a permutation test. The results show that distance from the shoreline had the greatest influence on the majority of the heavy metal concentrations in the lichen thalli and the soil. However, the level of Mn accumulated in the soil is determined by its source in the glacier. Moreover, the soil pH had the greatest effect on the Cd accumulated in the soil and the Mn accumulated in the lichen thalli.

[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.

Progress in the biosensing techniques for trace-level heavy metals.

PubMed

Mehta, Jyotsana; Bhardwaj, Sanjeev K; Bhardwaj, Neha; Paul, A K; Kumar, Pawan; Kim, Ki-Hyun; Deep, Akash

2016-01-01

Diverse classes of sensors have been developed over the past few decades for on-site detections of heavy metals. Most of these sensor systems have exploited optical, electrochemical, piezoelectric, ion-selective (electrode), and electrochemical measurement techniques. As such, numerous efforts have been made to explore the role of biosensors in the detection of heavy metals based on well-known interactions between heavy metals and biomolecules (e.g. proteins, peptides, enzymes, antibodies, whole cells, and nucleic acids). In this review, we cover the recent progress made on different types of biosensors for the detection of heavy metals. Our major focus was examining the use of biomolecules for constructing these biosensors. The discussion is extended further to cover the biosensors' performance along with challenges and opportunities for practical utilization. Copyright © 2015 Elsevier Inc. All rights reserved.

Detection of heavy metal resistance bioluminescence bacteria using microplate bioassay method.

PubMed

Ranjitha, P; Karthy, E S

2012-01-01

Effects of different heavy metals on Vibrio harveyi, V. fischeri, Photobacterium phosphoreum and P. leiognathi were examined. Checkerboard assay was used for the detection of the natural metal tolerance levels of a large number of marine luminous eubacteria. 57 strains of luminous bacteria were investigated for their natural patterns of heavy metal tolerance. The behaviors of these strains were not homogeneous with respect to all metals tested, even within the strains belonging to the same genus. At least 1 to 4 different MICs were detected for every metal except barium and cobalt. Isolated bacteria were tested for the presence of plasmids using the modified alkaline lysis method, was effective for identification of plasmids of different sizes. This study revealed the frequency of the occurrence of plasmids in heavy metal resistance bacteria and inferred that plasmids are highly ubiquitous and predominant in most heavy metal resistant bacteria.

Oxidative stress, glutathione level and antioxidant response to heavy metals in multi-resistant pathogen, Candida tropicalis.

PubMed

Ilyas, Sidra; Rehman, Abdul

2015-01-01

In this study, we explored the multiple heavy metal-resistant yeast isolated from heavy metal-polluted environment. The isolated yeast showed maximum growth at 30 °C, pH 7.0, and the strain was identified as Candida tropicalis through 18S ribosomal RNA (rRNA) gene sequence analysis. Yeast cells grew well in medium containing different concentrations of heavy metal ions [CdCl₂, Pb(NO₃)₂, NaAsO₂, CuSO₄ and K₂Cr₂O₇]. Minimum inhibitory concentration (MIC) against different metal ions was ranged from 5 to 19 mM, and the metal resistance value against each metal observed by yeast cells was 5 mM (Cr), 10 mM (Cd), 15 mM (As), 14 mM (Cu) and 19 mM (Pb) and increased in the following order: Pb > Cu > As ≥ Cd > Cr. The total cellular glutathione, GSH/GSSG redox couple and metallothioneins like protein (MT) were assayed by growing cultures for 24 h and exposed to 100 mg/L of each heavy metal ion. Remarkable increase in γ-glutamylcysteinylglycine (GSH) level was determined in arsenic and cadmium treatment followed by chromium, lead and copper. Stressed cells had much more oxidized GSH than unstressed cells. GSH/GSSG ratio was significantly increased in cadmium and copper treatment in contrast to chromium, arsenic and lead. Statistical analysis revealed significantly higher cysteine level in all metal-treated samples as compared to control. Antioxidant glutathione transferase activity was not detected in metal-treated and untreated yeast samples. One-dimensional electrophoresis of proteins revealed marked differences in banding pattern of heavy metal-exposed yeast samples. A prominent 20 kDa band was observed in all treated samples suggesting that some differential proteins could be over-expressed during heavy metal treatment and might be involved in cell resistance mechanisms.

Heavy Metal Music and Adolescent Suicidality: An Empirical Investigation.

ERIC Educational Resources Information Center

Scheel, Karen R.; Westefeld, John S.

1999-01-01

Investigates the relationship between preference for heavy metal music and vulnerability to suicide among high school students. Results indicate that preference for heavy metal music among adolescents may be sign of increased suicidal vulnerability, but also suggests that the source of the problem may lie more in personal and familial…

Traversing the Links between Heavy Metal Stress and Plant Signaling

PubMed Central

Jalmi, Siddhi K.; Bhagat, Prakash K.; Verma, Deepanjali; Noryang, Stanzin; Tayyeba, Sumaira; Singh, Kirti; Sharma, Deepika; Sinha, Alok K.

2018-01-01

Plants confront multifarious environmental stresses widely divided into abiotic and biotic stresses, of which heavy metal stress represents one of the most damaging abiotic stresses. Heavy metals cause toxicity by targeting crucial molecules and vital processes in the plant cell. One of the approaches by which heavy metals act in plants is by over production of reactive oxygen species (ROS) either directly or indirectly. Plants act against such overdose of metal in the environment by boosting the defense responses like metal chelation, sequestration into vacuole, regulation of metal intake by transporters, and intensification of antioxidative mechanisms. This response shown by plants is the result of intricate signaling networks functioning in the cell in order to transmit the extracellular stimuli into an intracellular response. The crucial signaling components involved are calcium signaling, hormone signaling, and mitogen activated protein kinase (MAPK) signaling that are discussed in this review. Apart from signaling components other regulators like microRNAs and transcription factors also have a major contribution in regulating heavy metal stress. This review demonstrates the key role of MAPKs in synchronously controlling the other signaling components and regulators in metal stress. Further, attempts have been made to focus on metal transporters and chelators that are regulated by MAPK signaling. PMID:29459874

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.

Temporal trends and bioavailability assessment of heavy metals in the sediments of Deception Bay, Queensland, Australia.

PubMed

Brady, James P; Ayoko, Godwin A; Martens, Wayde N; Goonetilleke, Ashantha

2014-12-15

Thirteen sites in Deception Bay, Queensland, Australia were sampled three times over a period of 7 months and assessed for contamination by a range of heavy metals, primarily As, Cd, Cr, Cu, Pb and Hg. Fraction analysis, enrichment factors and Principal Components Analysis-Absolute Principal Component Scores (PCA-APCS) analysis were conducted in order to identify the potential bioavailability of these elements of concern and their sources. Hg and Te were identified as the elements of highest enrichment in Deception Bay while marine sediments, shipping and antifouling agents were identified as the sources of the Weak Acid Extractable Metals (WE-M), with antifouling agents showing long residence time for mercury contamination. This has significant implications for the future of monitoring and regulation of heavy metal contamination within Deception Bay. Copyright © 2014 Elsevier Ltd. All rights reserved.

Heavy Metal Distribution in Street Dust from Traditional Markets and the Human Health Implications.

PubMed

Kim, Jin Ah; Park, Jin Hee; Hwang, Won Ju

2016-08-13

Street dust is a hazard for workers in traditional markets. Exposure time is longer than for other people, making them vulnerable to heavy metals in street dust. This study investigated heavy metal concentrations in street dust samples collected from different types of markets. It compared the results with heavy metal concentrations in heavy traffic and rural areas. Street dust was significantly enriched with most heavy metals in a heavy traffic area while street dust from a fish market was contaminated with cupper (Cu), lead (Pb) and zinc (Zn). Street dust from medicinal herb and fruit markets, and rural areas were not contaminated. Principal component and cluster analyses indicated heavy metals in heavy traffic road and fish market dust had different sources. Relatively high heavy metal concentration in street dust from the fish market may negatively affect worker's mental health, as depression levels were higher compared with workers in other markets. Therefore, intensive investigation of the relationship between heavy metal concentrations in street dust and worker's health in traditional marketplaces should be conducted to elucidate the effect of heavy metals on psychological health in humans.

Heavy Metal Distribution in Street Dust from Traditional Markets and the Human Health Implications

PubMed Central

Kim, Jin Ah; Park, Jin Hee; Hwang, Won Ju

2016-01-01

Street dust is a hazard for workers in traditional markets. Exposure time is longer than for other people, making them vulnerable to heavy metals in street dust. This study investigated heavy metal concentrations in street dust samples collected from different types of markets. It compared the results with heavy metal concentrations in heavy traffic and rural areas. Street dust was significantly enriched with most heavy metals in a heavy traffic area while street dust from a fish market was contaminated with cupper (Cu), lead (Pb) and zinc (Zn). Street dust from medicinal herb and fruit markets, and rural areas were not contaminated. Principal component and cluster analyses indicated heavy metals in heavy traffic road and fish market dust had different sources. Relatively high heavy metal concentration in street dust from the fish market may negatively affect worker’s mental health, as depression levels were higher compared with workers in other markets. Therefore, intensive investigation of the relationship between heavy metal concentrations in street dust and worker’s health in traditional marketplaces should be conducted to elucidate the effect of heavy metals on psychological health in humans. PMID:27529268

Selection of ectomycorrhizal willow genotype in phytoextraction of heavy metals.

PubMed

Hrynkiewicz, Katarzyna; Baum, Christel

2013-01-01

Willow clones are used for the phytoextraction of heavy metals from contaminated soils and are usually mycorrhizal. The receptiveness of willow clones for mycorrhizal inoculum varies specific to genotype; however, it is unknown if this might have a significant impact on their efficiency in phytoextraction of heavy metals. Therefore, a model system with mycorrhizal and non-mycorrhizal willows of two different genotypes--one with usually stronger natural mycorrhizal colonization (Salix dasyclados), and one with lower natural mycorrhizal colonization (S. viminalis)--was investigated for its efficiency of phytoextraction of heavy metals (Cd, Pb, Cu, Zn) from contaminated soil. Inoculation with the ectomycorrhizal fungus Amanita muscaria significantly decreased the biomass of leaves of both inoculated willow clones, and increased or had no effect on the biomass of trunks and roots of S. dasyclados and S. viminalis, respectively. The concentrations of heavy metals in the biomass of S. dasyclados were in general higher than in S. viminalis irrespective of inoculation with the ectomycorrhizal fungus. Inoculation with A. muscaria significantly decreased the concentration of Cu in the trunks of both Salix taxa, but did not affected the concentrations of other heavy metals in the biomass. In conclusion, stronger receptiveness of willow clones for mycorrhizal inoculum was correlated with an increased total extraction of heavy metals from contaminated soils. Therefore, this seems to be a suitable criterion for effective willow clone selection for phytoremediation. Increased biomass production with relatively constant metal concentrations seems to be a major advantage of mycorrhizal formation of willows in phytoremediation of contaminated soils.

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.

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.

Assessment of bioavailability of heavy metal pollutants using soil isolates of Chlorella sp.

PubMed

Krishnamurti, Gummuluru S R; Subashchandrabose, Suresh R; Megharaj, Mallavarapu; Naidu, Ravi

2015-06-01

Biotests conducted with plants are presently used to estimate metal bioavailability in contaminated soils. But when plants are grown in soils, especially the plants with fine roots, root collection is easily biased and tedious. Indeed, at harvest, small amounts of soil can adhere to roots, resulting in overestimation of root metal content, and the finest roots are often discarded from the analysis because of their difficult and almost impossible recovery. This report presents a novel method for assessing the bioavailability of heavy metals in soils using microalgae. Two species of green unicellular microalgae were isolated from two highly contaminated soils and identified by phylogenetic and molecular evolutionary analyses as Chlorella sp. RBM and Chlorella sp. RHM. These two cultures were used to determine the metal uptake from metal-contaminated soils of South Australia as a novel, cost-effective, simple and rapid method for assessing the bioavailability of heavy metals in soils. The suggested method is an attempt to achieve a realistic estimate of bioavailability which overcomes the inherent drawback of root metal contamination in the bioavailability indices so far reported.

Characterization of heavy metal desorption from road-deposited sediment under acid rain scenarios.

PubMed

Zhao, Bo; Liu, An; Wu, Guangxue; Li, Dunzhu; Guan, Yuntao

2017-01-01

Road-deposited sediments (RDS) on urban impervious surfaces are important carriers of heavy metals. Dissolved heavy metals that come from RDS influenced by acid rain, are more harmful to urban receiving water than particulate parts. RDS and its associated heavy metals were investigated at typical functional areas, including industrial, commercial and residential sites, in Guangdong, Southern China, which was an acid rain sensitive area. Total and dissolved heavy metals in five particle size fractions were analyzed using a shaking method under acid rain scenarios. Investigated heavy metals showed no difference in the proportion of dissolved fraction in the solution under different acid rain pHs above 3.0, regardless of land use. Dissolved loading of heavy metals related to organic carbon content were different in runoff from main traffic roads of three land use types. Coarse particles (>150μm) that could be efficiently removed by conventional street sweepers, accounted for 55.1%-47.1% of the total dissolved metal loading in runoff with pH3.0-5.6. The obtained findings provided a significant scientific basis to understand heavy metal release and influence of RDS grain-size distribution and land use in dissolved heavy metal pollution affected by acid rain. Copyright © 2016. Published by Elsevier B.V.

A review of soil heavy metal pollution from mines in China: pollution and health risk assessment.

PubMed

Li, Zhiyuan; Ma, Zongwei; van der Kuijp, Tsering Jan; Yuan, Zengwei; Huang, Lei

2014-01-15

Heavy metal pollution has pervaded many parts of the world, especially developing countries such as China. This review summarizes available data in the literature (2005-2012) on heavy metal polluted soils originating from mining areas in China. Based on these obtained data, this paper then evaluates the soil pollution levels of these collected mines and quantifies the risks these pollutants pose to human health. To assess these potential threat levels, the geoaccumulation index was applied, along with the US Environmental Protection Agency (USEPA) recommended method for health risk assessment. The results demonstrate not only the severity of heavy metal pollution from the examined mines, but also the high carcinogenic and non-carcinogenic risks that soil heavy metal pollution poses to the public, especially to children and those living in the vicinity of heavily polluted mining areas. In order to provide key management targets for relevant government agencies, based on the results of the pollution and health risk assessments, Cd, Pb, Cu, Zn, Hg, As, and Ni are selected as the priority control heavy metals; tungsten, manganese, lead-zinc, and antimony mines are selected as the priority control mine categories; and southern provinces and Liaoning province are selected as the priority control provinces. This review, therefore, provides a comprehensive assessment of soil heavy metal pollution derived from mines in China, while identifying policy recommendations for pollution mitigation and environmental management of these mines. © 2013.

A versatile MOF-based trap for heavy metal ion capture and dispersion.

PubMed

Peng, Yaguang; Huang, Hongliang; Zhang, Yuxi; Kang, Chufan; Chen, Shuangming; Song, Li; Liu, Dahuan; Zhong, Chongli

2018-01-15

Current technologies for removing heavy metal ions are typically metal ion specific. Herein we report the development of a broad-spectrum heavy metal ion trap by incorporation of ethylenediaminetetraacetic acid into a robust metal-organic framework. The capture experiments for a total of 22 heavy metal ions, covering hard, soft, and borderline Lewis metal ions, show that the trap is very effective, with removal efficiencies of >99% for single-component adsorption, multi-component adsorption, or in breakthrough processes. The material can also serve as a host for metal ion loading with arbitrary selections of metal ion amounts/types with a controllable uptake ratio to prepare well-dispersed single or multiple metal catalysts. This is supported by the excellent performance of the prepared Pd 2+ -loaded composite toward the Suzuki coupling reaction. This work proposes a versatile heavy metal ion trap that may find applications in the fields of separation and catalysis.

Characterization of landfill leachates and studies on heavy metal removal.

PubMed

Ceçen, F; Gürsoy, G

2000-10-01

This study covers a thorough characterisation of landfill leachates emerging from a sanitary landfill area. The landfill leachates were obtained in the acidic stage of landfill stabilisation. Their organic content was high as reflected by the high BOD5 (5 day biological oxygen demand) and COD (chemical oxygen demand) values. They were also highly polluted in terms of the parameters TKN (total Kjeldahl nitrogen), NH4-N, alkalinity, hardness and heavy metals. Nickel was present in these wastewaters at a significant concentration. With regard to the high heavy metal content of these wastewaters, several physicochemical removal alternatives for the heavy metals Cu, Pb, Zn, Ni, Cd, Cr, Mn and Fe were tested using coagulation, flocculation, precipitation, base addition and aeration. Additionally, COD removal and ammonia stripping were examined. Co-precipitation with either alum or iron salts did not usually lead to significantly higher heavy metal removal than lime alone. The major methods leading to an effective heavy metal removal were aeration and lime addition. Nickel and cadmium seemed to be strongly complexed and were not removed by any method. Also lead removal proved to be difficult. The results are also discussed in terms of compliance with standards.

Implications of soil pollution with heavy metals for public health

NASA Astrophysics Data System (ADS)

Juozulynas, Algirdas; Jurgelėnas, Antanas; Butkienė, Birutė; Greičiūtė, Kristina; Savičiūtė, Rasa

2008-01-01

Soil of military grounds is often polluted with heavy metals. Their concentrations may be dosens of times higher in polluted regions. The affected soils are permeable, so the pollutions can get into water and spread to the environment. Into human and animal organisms they can get with food and water. Heavy metals are very dangerous for people's health, and we must know their accumulation places, intensity of scatter and integral risk for health. The purpose of this work was to establish links between zones polluted with heavy metals and morbidity caused by pollution with heavy metals. The morbidity caused by heavy metals (Pb, Cu, Zn, Ca and other) in the polluted regions is 1.4-1.5 times higher for adults and teenagers and 1.5-3.9 times higher for children aged under 14 years than the mean morbidity of the same diseases in Lithuania. Hypothetically, it is possible to prognosticate that this problem will grow in future because the ratio of the newly registered and the existing cases of morbidity for children aged under 14 years is 1.3-1.5 times higher than for adults.

Heavy Metal Pollution from Gold Mines: Environmental Effects and Bacterial Strategies for Resistance.

PubMed

Fashola, Muibat Omotola; Ngole-Jeme, Veronica Mpode; Babalola, Olubukola Oluranti

2016-10-26

Mining activities can lead to the generation of large quantities of heavy metal laden wastes which are released in an uncontrolled manner, causing widespread contamination of the ecosystem. Though some heavy metals classified as essential are important for normal life physiological processes, higher concentrations above stipulated levels have deleterious effects on human health and biota. Bacteria able to withstand high concentrations of these heavy metals are found in the environment as a result of various inherent biochemical, physiological, and/or genetic mechanisms. These mechanisms can serve as potential tools for bioremediation of heavy metal polluted sites. This review focuses on the effects of heavy metal wastes generated from gold mining activities on the environment and the various mechanisms used by bacteria to counteract the effect of these heavy metals in their immediate environment.

Heavy Metal Pollution from Gold Mines: Environmental Effects and Bacterial Strategies for Resistance

PubMed Central

Fashola, Muibat Omotola; Ngole-Jeme, Veronica Mpode; Babalola, Olubukola Oluranti

2016-01-01

Mining activities can lead to the generation of large quantities of heavy metal laden wastes which are released in an uncontrolled manner, causing widespread contamination of the ecosystem. Though some heavy metals classified as essential are important for normal life physiological processes, higher concentrations above stipulated levels have deleterious effects on human health and biota. Bacteria able to withstand high concentrations of these heavy metals are found in the environment as a result of various inherent biochemical, physiological, and/or genetic mechanisms. These mechanisms can serve as potential tools for bioremediation of heavy metal polluted sites. This review focuses on the effects of heavy metal wastes generated from gold mining activities on the environment and the various mechanisms used by bacteria to counteract the effect of these heavy metals in their immediate environment. PMID:27792205

Speciation and transformation of heavy metals during vermicomposting of animal manure.

PubMed

Lv, Baoyi; Xing, Meiyan; Yang, Jian

2016-06-01

This work was conducted to evaluate the effects of vermicomposting on the speciation and mobility of heavy metals (Zn, Pb, Cr, and Cu) in cattle dung (CD) and pig manure (PM) using tessier sequential extraction method. Results showed that the pH, total organic carbon and C/N ratio were reduced, while the electric conductivity and humic acid increased after 90days vermicomposting. Moreover, the addition of earthworm could accelerate organic stabilization in vermicomposting. The total heavy metals in final vermicompost from CD and PM were higher than the initial values and the control without worms. Sequential extraction indicated that vermicomposting decreased the migration and availability of heavy metals, and the earthworm could reduce the mobile fraction, while increase the stable fraction of heavy metals. Furthermore, these results indicated that vermicomposting played a positive role in stabilizing heavy metals in the treatment of animal manure. Copyright © 2016 Elsevier Ltd. All rights reserved.

Heavy metal ion removal by thiol functionalized aluminum oxide hydroxide nanowhiskers

NASA Astrophysics Data System (ADS)

Xia, Zhiyong; Baird, Lance; Zimmerman, Natasha; Yeager, Matthew

2017-09-01

In this study, we developed a cost effective method of using thiol functionalized γ-aluminum oxide hydroxide (γ-AlOOH) filters for removing three key heavy metals from water: mercury, lead, and cadmium under non-concomitant conditions. Compared to non-thiol treated γ-AlOOH filters, the introduction of thiol functional groups greatly improved the heavy metal removal efficiency under both static and dynamic filtration conditions. The adsorption kinetics of thiol functionalized γ-AlOOH were investigated using the Lagergren first order and pseudo-second order kinetics models; whereas the isothermal adsorption behavior of these membranes was revealed through the Langmuir and Freundlich models. Heavy metal concentration was quantified by Inductively Coupled Plasma-Mass Spectroscopy, and the thiol level on γ-AlOOH surface was measured by a colorimetric assay using Ellman's reagent. X-ray photoelectron spectroscopy was used to further address the surface sulfur state on the membranes after heavy metal exposure. Mechanisms for heavy metal adsorption were also discussed.

Supercritical water treatment of heavy metal and arsenic metalloid-bioaccumulating-biomass.

PubMed

Li, Jianxin; Chen, Jinbo; Chen, Shan

2018-08-15

Hyperaccumulator biomass, as a promising resource for renewable energy that can be converted into valuable fuel productions with high conversion efficiency, must be considered as hazardous materials and be carefully treated before further reuse due to the high contents of heavy metals. In this study, Pteris vittata L., an As-hyperaccumulator biomass was treated by an effective and environmental friendly method-supercritical water gasification (SCWG) using a bench-scale batch reactor. The contents of heavy metals (Cd, Pb and Zn) and arsenic metalloid in solid, liquid and gaseous products during SCWG process were thoroughly investigated. The speciation fractions including exchangeable, reducible, oxidizable and residual fractions of each heavy metal as the proportion of the total contents in solid residue were presented and the transformations trend of these heavy metals during the SCWG process was especially demonstrated. The significant operating parameters, including reaction temperature (395-445 °C), pressure (21-27 MPa) and residence time (0-40 min) were varied to explore their effects on the contents and forms. Moreover, the environmental risks of heavy metals in solid residues were evaluated based on risk assessment code, taking into consideration the speciation fractions and bioavailability. It was highlighted that although heavy metals particularly Pb and Zn tended to accumulate in solid residues with a maximum increment of about 50% in the total content, they were mostly converted to more stable oxidizable and residual fractions, and thus the ecotoxicity and bioavailability were greatly mitigated with no obvious increase in direct toxicity fractions. Each tested heavy metal presented no or low risk to the environments after SCWG treatments, meaning that the environmental pollution levels were markedly reduced with no or low risk to the environment. This study highlights the remarkable ability of SCWG for the heavy metal stabilization. Copyright �

Spatial distribution and sources of heavy metals in natural pasture soil around copper-molybdenum mine in Northeast China.

PubMed

Wang, Zhiqiang; Hong, Chen; Xing, Yi; Wang, Kang; Li, Yifei; Feng, Lihui; Ma, Silu

2018-06-15

The characterization of the content and source of heavy metals are essential to assess the potential threat of metals to human health. The present study collected 140 topsoil samples around a Cu-Mo mine (Wunugetushan, China) and investigated the concentrations and spatial distribution pattern of Cr, Ni, Zn, Cu, Mo and Cd in soil using multivariate and geostatistical analytical methods. Results indicated that the average concentrations of six heavy metals, especially Cu and Mo, were obviously higher than the local background values. Correlation analysis and principal component analysis divided these metals into three groups, including Cr and Ni, Cu and Mo, Zn and Cd. Meanwhile, the spatial distribution maps of heavy metals indicated that Cr and Ni in soil were no notable anthropogenic inputs and mainly controlled by natural factors because their spatial maps exhibited non-point source contamination. The concentrations of Cu and Mo gradually decreased with distance away from the mine area, suggesting that human mining activities may be crucial in the spreading of contaminants. Soil contamination of Zn were associated with livestock manure produced from grazing. In addition, the environmental risk of heavy metal pollution was assessed by geo-accumulation index. All the results revealed that the spatial distribution of heavy metals in soil were in agreement with the local human activities. Investigating and identifying the origin of heavy metals in pasture soil will lay the foundation for taking effective measures to preserve soil from the long-term accumulation of heavy metals. Copyright © 2018 Elsevier Inc. All rights reserved.

Heavy-metal detectors based on modified ferrite nanoparticles

PubMed Central

Klekotka, Urszula; Wińska, Ewelina; Zambrzycka-Szelewa, Elżbieta; Satuła, Dariusz

2018-01-01

In this work, we analyze artificial heavy-metal solutions with ferrite nanoparticles. Measurements of adsorption effectiveness of different kinds of particles, pure magnetite or magnetite doped with calcium, cobalt, manganese, or nickel ions, were carried out. A dependence of the adsorption efficiency on the composition of the inorganic core has been observed. Ferrites surfaces were modified by phthalic anhydride (PA), succinic anhydride (SA), acetic anhydride (AA), 3-phosphonopropionic acid (3-PPA), or 16-phosphohexadecanoic acid (16-PHDA) to compare the adsorption capability of the heavy metals Cd, Cu and Pb. The obtained nanoparticles were structurally characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Mössbauer spectroscopy. The amounts of Cd, Cu and Pb were measured out by atomic absorption spectroscopy (AAS) and energy dispersive X-ray (EDX) as comparative techniques. The performed study shows that SA linker appears to be the most effective in the adsorption of heavy metals. Moreover, regarding the influence of the composition of the inorganic core on the detection ability, the most effective ferrite Mn0.5Fe2.5O4 was selected for discussion. The highest heavy-metal adsorption capability and universality was observed for SA as a surface modifier. PMID:29600137

Heavy-metal detectors based on modified ferrite nanoparticles.

PubMed

Klekotka, Urszula; Wińska, Ewelina; Zambrzycka-Szelewa, Elżbieta; Satuła, Dariusz; Kalska-Szostko, Beata

2018-01-01

In this work, we analyze artificial heavy-metal solutions with ferrite nanoparticles. Measurements of adsorption effectiveness of different kinds of particles, pure magnetite or magnetite doped with calcium, cobalt, manganese, or nickel ions, were carried out. A dependence of the adsorption efficiency on the composition of the inorganic core has been observed. Ferrites surfaces were modified by phthalic anhydride (PA), succinic anhydride (SA), acetic anhydride (AA), 3-phosphonopropionic acid (3-PPA), or 16-phosphohexadecanoic acid (16-PHDA) to compare the adsorption capability of the heavy metals Cd, Cu and Pb. The obtained nanoparticles were structurally characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Mössbauer spectroscopy. The amounts of Cd, Cu and Pb were measured out by atomic absorption spectroscopy (AAS) and energy dispersive X-ray (EDX) as comparative techniques. The performed study shows that SA linker appears to be the most effective in the adsorption of heavy metals. Moreover, regarding the influence of the composition of the inorganic core on the detection ability, the most effective ferrite Mn 0.5 Fe 2.5 O 4 was selected for discussion. The highest heavy-metal adsorption capability and universality was observed for SA as a surface modifier.

Heavy metals hazards from Nigerian spices.

PubMed

Asomugha, Rose Ngozi; Udowelle, Nnaemeka Arinze; Offor, Samuel James; Njoku, Chinonso Judith; Ofoma, Ifeoma Victoria; Chukwuogor, Chiaku Chinwe; Orisakwe, Orish Ebere

Natural spices are commonly used by the people in Nigeria. They may be easily contaminated with heavy metals when they are dried and then pose a health risk for the consumers. The aim of this study was to determine the levels of heavy metals in some commonly consumed natural spices namely Prosopis Africana, Xylopia aethiopica, Piper gineense, Monodora myristica, Monodora tenuifolia and Capsicum frutescens sold in the local markets of Awka, Anambra state, South East Nigeria to estimate the potential health risk. The range of heavy metal concentration was in the order: Zn (14.09 - 161.04) > Fe (28.15 - 134.59) > Pb (2.61 - 8.97) > Cr (0.001 - 3.81) > Co (0.28 - 3.07) > Ni (0.34 - 2.89). Pb, Fe and Zn exceeded the maximum allowable concentrations for spices. The Target Hazard Quotient (THQ) of the spices varied from 0.06-0.5. Estimated daily intakes (EDI) were all below the tolerable daily intake (TDI). The lead levels in Prosopis africana, Xylopia aethiopica, Piper gineense, Monodora myristica and Capsicum frutescens which are 8-30 times higher than the WHO/FAO permissible limit of 0.3 mg/kg. Lead contamination of spices sold in Awka (south east Nigeria) may add to the body burden of lead. A good quality control for herbal food is important in order to protect consumers from contamination. food products, spices, potential toxic metals, risk assessment, public health.

Interactions between plant hormones and heavy metals responses.

PubMed

Bücker-Neto, Lauro; Paiva, Ana Luiza Sobral; Machado, Ronei Dorneles; Arenhart, Rafael Augusto; Margis-Pinheiro, Marcia

2017-01-01

Heavy metals are natural non-biodegradable constituents of the Earth's crust that accumulate and persist indefinitely in the ecosystem as a result of human activities. Since the industrial revolution, the concentration of cadmium, arsenic, lead, mercury and zinc, amongst others, have increasingly contaminated soil and water resources, leading to significant yield losses in plants. These issues have become an important concern of scientific interest. Understanding the molecular and physiological responses of plants to heavy metal stress is critical in order to maximize their productivity. Recent research has extended our view of how plant hormones can regulate and integrate growth responses to various environmental cues in order to sustain life. In the present review we discuss current knowledge about the role of the plant growth hormones abscisic acid, auxin, brassinosteroid and ethylene in signaling pathways, defense mechanisms and alleviation of heavy metal toxicity.

Native herbaceous plant species with potential use in phytoremediation of heavy metals, spotlight on wetlands - A review.

PubMed

Oyuela Leguizamo, Mayerly Alexandra; Fernández Gómez, Wilmar Darío; Sarmiento, Martha Cecilia Gutiérrez

2017-02-01

Soil, air and water pollution caused by the mobility and solubility of heavy metals significantly damages the environment, human health, plants and animals. One common in situ method used for the decontamination of heavy metals is phytoremediation. This usually involves the use of exotic species. However, these species may exhibit invasive behavior, thereby, affect the environmental and ecological dynamics of the ecosystem into which they are introduced. This paper focuses on some native herbaceous plant species reported on the wetlands of Bogota, Colombia, with potential use in phytoremediation of heavy metals. To do that, the authors identified and searched a bibliography based on key words related to heavy metal decontamination. In addition, authors gathered and analyzed relevant information that allowed the comprehension of the phytoremediation process. This paper suggests the study of 41 native or endemic species regarding their behavior towards heavy metal contamination. From a survey of herbaceous plants reported in Bogota, native and endemic species that belong to predominant families in heavy metal accumulation processes were selected. Although found in Colombian's wetlands, these can also be found worldwide. Therefore, they are of great interest due to their global presence and their potential for use in phytoremediation. The current research about the development of phytoremediation focuses on the identification of new herbaceous species able to decontaminate substratum polluted with heavy metals to contribute with the investigation of the ecology and environment of the nature's remnants in urban wetland ecosystems. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Characteristics of heavy metals enrichment in algae ano its application prospects].

PubMed

Lu, Kaixing; Tang, Jian-jun; Jiang, De'an

2006-01-01

Using algae to bio-remedy heavy metals-contaminated waters has become an available and practical approach for environmental restoration. Because of its special cell wall structure, high capacity of heavy metal-enrichment, and easy to desorption, algae has been considered as an ideal biological adsorbent. This paper briefly introduced the structural and metabolic characteristics adapted for heavy metals enrichment of algae, including functional groups on cell wall, extracellular products, and intracellular heavy metals-chelating proteins, discussed the enrichment capability of living, dead and immobilized algae as well as the simple and convenient ways for desorption, and analyzed the advantages and disadvantages of using algae for bioremediation of polluted water, and its application prospects.

MRP proteins as potential mediators of heavy metal resistance in zebrafish cells.

PubMed

Long, Yong; Li, Qing; Wang, Youhui; Cui, Zongbin

2011-04-01

Acquired resistance of mammalian cells to heavy metals is closely relevant to enhanced expression of several multidrug resistance-associated proteins (MRP), but it remains unclear whether MRP proteins confer resistance to heavy metals in zebrafish. In this study, we obtained zebrafish (Danio rerio) fibroblast-like ZF4 cells with resistance to toxic heavy metals after chronic cadmium exposure and selection for 6months. These cadmium-resistant cells (ZF4-Cd) were maintained in 5μM cadmium and displayed cross-resistance to cadmium, mercury, arsenite and arsenate. ZF4-Cd cells remained the resistance to heavy metals after protracted culture in cadmium-free medium. In comparison with ZF4-WT cells, ZF4-Cd cells exhibited accelerated rate of cadmium excretion, enhanced activity of MRP-like transport, elevated expression of abcc2, abcc4 and mt2 genes, and increased content of cellular GSH. Inhibition of MRP-like transport activity, GSH biosynthesis and GST activity significantly attenuated the resistance of ZF4-Cd cells to heavy metals. The results indicate that some of MRP transporters are involved in the efflux of heavy metals conjugated with cellular GSH and thus play crucial roles in heavy metal detoxification of zebrafish cells. Copyright © 2010 Elsevier Inc. All rights reserved.

Radionuclides and heavy metals in Borovac, Southern Serbia.

PubMed

Popovic, Dragana; Todorovic, Dragana; Frontasyeva, Marina; Ajtic, Jelena; Tasic, Mirjana; Rajsic, Slavica

2008-09-01

, honey, and water in Southern Serbia (Bujanovac) gave no evidence of the DU contamination of the environment 5 years after the military actions in 1999. Activities of radionuclides in soils were within the range of the values obtained in the other parts of the country and within the global average. The ratio of uranium isotopes confirmed the natural origin of uranium. In general, concentrations of heavy metals in the samples of soils, plant leaves, mosses, and lichen are found to be less or in the lower range of values found in other parts of the country, in spite of the differences in plant and moss species or soil characteristics. Possible sources of heavy metal contamination were identified as a power coal plant in the vicinity of the sampling sites and wood and waste burning processes. The collected data should provide a base for the health risk assessments on animals and humans in the near future. It should be emphasized that the sampling was carried out 5 years after the military action and that the number of samples was limited; therefore, the conclusions should be accepted only as observed tendencies and a detailed study should be recommended in the future.

Black water sludge reuse in agriculture: are heavy metals a problem?

PubMed

Tervahauta, Taina; Rani, Sonia; Hernández Leal, Lucía; Buisman, Cees J N; Zeeman, Grietje

2014-06-15

Heavy metal content of sewage sludge is currently the most significant factor limiting its reuse in agriculture within the European Union. In the Netherlands most of the produced sewage sludge is incinerated, mineralizing the organic carbon into the atmosphere rather than returning it back to the soil. Source-separation of black water (toilet water) excludes external heavy metal inputs, such as industrial effluents and surface run-offs, producing sludge with reduced heavy metal content that is a more favorable source for resource recovery. The results presented in this paper show that feces is the main contributor to the heavy metal loading of vacuum collected black water (52-84%), while in sewage the contribution of feces is less than 10%. To distinguish black water from sewage in the sludge reuse regulation, a control parameter should be implemented, such as the Hg and Pb content that is significantly higher in sewage sludge compared to black water sludge (from 50- to 200-fold). The heavy metals in feces and urine are primarily from dietary sources, and promotion of the soil application of black water sludge over livestock manure and artificial fertilizers could further reduce the heavy metal content in the soil/food cycle. Copyright © 2014 Elsevier B.V. All rights reserved.

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

Soil Heavy Metal Pollution and Risk Assessment in Shenyang Industrial District, Northeast China

PubMed Central

Jiao, Xudong; Teng, Yanguo; Zhan, Yanhong; Wu, Jin; Lin, Xueyu

2015-01-01

To investigate the soil heavy metal pollution characteristics and ecological risk factors, 42 samples and six typical soil profiles were collected from the Shenyang industrial district in northeast China and were analyzed for contents of titanium (Ti), copper (Cu), lead (Pb), zinc (Zn), cobalt (Co), nickel (Ni), chromium (Cr) and arsenic (As). Through statistical analysis, it was found that the mean concentrations were higher than their background values (Ti = 4.77>3.8g/kg, Cu = 33.75>22.6 mg/kg, Pb = 45.95>26 mg/kg, Zn = 81.54>74.2 mg/kg, Co = 12.91>12.7 mg/kg, Ni = 32.26>26.9 mg/kg, Cr = 83.36>61 mg/kg and As = 13.69>11.2 mg/kg) but did not exceed their corresponding pollution limits for the Chinese Environmental Quality Standard for Soils (State Environmental Protection Administration of China, 1995). There were contamination hotspots that may be caused by human activities such as smelting plants and sewage irrigation. The Enrichment Factor and Ecological Risk Index were used to identify the anthropogenic contamination and ecological risks of heavy metals. Soil in the study area could be considered lightly or partially polluted by heavy metals. According to clustering analysis, distinct groups of heavy metals were discriminated between natural or anthropogenic sources. PMID:25997173

Bioethanol production from recovered napier grass with heavy metals.

PubMed

Ko, Chun-Han; Yu, Fan-Chun; Chang, Fang-Chih; Yang, Bing-Yuan; Chen, Wen-Hua; Hwang, Wen-Song; Tu, Ta-Chih

2017-12-01

Using plants to absorb and accumulate heavy metals from polluted soil, followed by the recycling of explants containing heavy metals, can help achieve the goal of reverting contaminated soil to low heavy-metal content soil. However, the re-use of recovered explants can also be problematic. Meanwhile, bioethanol has become a popular energy source. In this study, napier grass was used for the remediation of soil contaminated with heavy metals (artificially contaminated soil). The influence of bioethanol production from napier grass after phytoremediation was also investigated. The concentration of Zn, Cd, and Cr in the contaminated soil was 1000, 100, and 250 mg/kg, respectively. After napier grass phytoremediation, the concentration (dry biomass) of Zn, Cd, and Cr in the explants was 2701.97 ± 173.49, 6.1 ± 2.3, and 74.24 ± 1.42 mg/kg, respectively. Biomass production in the unpolluted soil was 861.13 ± 4.23 g. The biomass production ratio in high Zn-polluted soil was only 3.89%, while it was 4.68% for Cd and 21.4% for Cr. The biomass obtained after napier grass phytoremediation was pretreated using the steam explosion conditions of 180 °C, for 10 min, with 1.5% H 2 SO 2 , followed by enzymatic hydrolysis. The efficiency of enzymatic hydrolysis for Zn-polluted biomass was 90% of the unpolluted biomass, while it was 77% for Cd, and approximately the same for Cr. The fermentation efficiency of the heavy-metal-containing biomass was higher than the control biomass. The fermentation ethanol concentration obtained was 8.69-12.68, 13.03-15.50, and 18.48-19.31 g/L in Zn, Cd, and Cr environments, respectively. Results show that the heavy metals had a positive effect on bacteria fermentation. However, the fermentation efficiency was lower for biomass with severe heavy metal pollution. Thus, the utilization of napier grass phytoremediation for bioethanol production has a positive effect on the sustainability of environmental resources. Copyright © 2017

Some heavy metals in Luciobarbus esocinus for public consumption and consumer protection.

PubMed

Düşükcan, M; Canpolat, Ö; Eroğlu, M

2017-09-30

In this study, the concentrations of some heavy metals were determined in the muscle of Luciobarbus esocinus Heckel, 1843 and in water where they live. The results were evaluated in term of potential human risk of consumption of this fish and the relationship between the heavy metal load of fish and some of their biological aspects (weight, length and sex). In addition, the accumulation factor of heavy metals in the muscle of L. esocinus were also determined. The Cr, Pb and Ni were not found in detectable levels according to results obtained by ICP. Only Cu, Zn and Fe were detected. It was found that heavy metals concentrations in the muscle of L. esocinus were higher than that in the water. The concentration of heavy metals showed differences according to weight, length and sex of fish. The results were discussed and compared with tolerable values for heavy metals provided from the EPA, FAO and WHO in order to determine whether this fish species has any risk for human consumption.

Phytoremediation strategies for soils contaminated with heavy metals: Modifications and future perspectives.

PubMed

Sarwar, Nadeem; Imran, Muhammad; Shaheen, Muhammad Rashid; Ishaque, Wajid; Kamran, Muhammad Asif; Matloob, Amar; Rehim, Abdur; Hussain, Saddam

2017-03-01

Presence of heavy metals in agricultural soils is of major environmental concern and a great threat to life on the earth. A number of human health risks are associated with heavy metals regarding their entry into food chain. Various physical, chemical and biological techniques are being used to remove heavy metals and metalloids from soils. Among them, phytoremediation is a good strategy to harvest heavy metals from soils and have been proven as an effective and economical technique. In present review, we discussed various sources and harmful effects of some important heavy metals and metalloids, traditional phytoremediation strategies, mechanisms involved in phytoremediation of these metals, limitations and some recent advances in phytoremediation approaches. Since traditional phytoremediation approach poses some limitations regarding their applications at large scale, so there is a dire need to modify this strategy using modern chemical, biological and genetic engineering tools. In view of above, the present manuscript brings both traditional and advanced phytoremediation techniques together in order to compare, understand and apply these strategies effectively to exclude heavy metals from soil keeping in view the economics and effectiveness of phytoremediation strategies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Research Progress of Artificial Forest in the Remediation of Heavy Metal Contaminated Soils

NASA Astrophysics Data System (ADS)

Jiafang, MA; Guangtao, MENG; Liping, HE; Guixiang, LI

2017-01-01

(1) Remediation of soil contaminated by heavy metals has become a hot topic in the world, and phytoremediation technology is the most widely used. (2) In addition to traditional economic benefits, ecological benefits of artificial forest have been more and more important, which are very helpful to soil polluted with heavy metals in the environment. (3) The characteristics of heavy metal pollution of soil and plantations of repair mechanism have been reviewed, and the current mining areas, wetlands, urban plantations on heavy metal elements have enriched the research results. The purpose is to find a new path for governance of heavy metal soil pollution.

Microplastics as vector for heavy metal contamination from the marine environment

NASA Astrophysics Data System (ADS)

Brennecke, Dennis; Duarte, Bernardo; Paiva, Filipa; Caçador, Isabel; Canning-Clode, João

2016-09-01

The permanent presence of microplastics in the marine environment is considered a global threat to several marine animals. Heavy metals and microplastics are typically included in two different classes of pollutants but the interaction between these two stressors is poorly understood. During 14 days of experimental manipulation, we examined the adsorption of two heavy metals, copper (Cu) and zinc (Zn), leached from an antifouling paint to virgin polystyrene (PS) beads and aged polyvinyl chloride (PVC) fragments in seawater. We demonstrated that heavy metals were released from the antifouling paint to the water and both microplastic types adsorbed the two heavy metals. This adsorption kinetics was described using partition coefficients and mathematical models. Partition coefficients between pellets and water ranged between 650 and 850 for Cu on PS and PVC, respectively. The adsorption of Cu was significantly greater in PVC fragments than in PS, probably due to higher surface area and polarity of PVC. Concentrations of Cu and Zn increased significantly on PVC and PS over the course of the experiment with the exception of Zn on PS. As a result, we show a significant interaction between these types of microplastics and heavy metals, which can have implications for marine life and the environment. These results strongly support recent findings where plastics can play a key role as vectors for heavy metal ions in the marine system. Finally, our findings highlight the importance of monitoring marine litter and heavy metals, mainly associated with antifouling paints, particularly in the framework of the Marine Strategy Framework Directive (MSFD).

Application of carbon nanotubes to immobilize heavy metals in contaminated soils

NASA Astrophysics Data System (ADS)

Matos, Martim P. S. R.; Correia, António Alberto S.; Rasteiro, Maria G.

2017-04-01

The contamination of soils with heavy metals is a growing concern in modern societies. To avoid the spread of contamination, soil stabilization techniques can be applied mixing materials with the soil in order to partially immobilize heavy metals. Carbon nanotubes (CNTs) are nanomaterials known for its exceptional properties, like high surface area and adsorption capacity. Due to these unique properties, the potential use of CNTs in heavy metal contaminated water has been studied, with very satisfactory results; however, their application in contaminated soils is practically unexplored. This experimental work is focused on studying the potential of using CNTs in soil remediation, especially to immobilize the heavy metals ions: lead (Pb2+), copper (Cu2+), nickel (Ni2+), and zinc (Zn2+), commonly present in contaminated soils. In order to avoid CNT agglomeration, which originates the loss of their beneficial properties, an aqueous suspension of CNTs was prepared using a non-ionic surfactant combined with ultrasonic energy to promote CNTs dispersion. Then, the soil, with and without the addition of CNTs, was subjected to adsorption tests to evaluate the CNT capacity to improve heavy metal immobilization. To validate the adsorption test results, permeability tests were executed, simulating the conditions of a real-case scenario. The results obtained led to the conclusion that the addition of a small amount of dispersed CNTs can successfully increase the adsorption capacity of the soil and consequently improve the immobilization of heavy metals in the soil matrix. The immobilization percentage varies with the different heavy metals under study.

Magnetic process for removing heavy metals from water employing magnetites

DOEpatents

Prenger, F. Coyne; Hill, Dallas D.; Padilla, Dennis D.; Wingo, Robert M.; Worl, Laura A.; Johnson, Michael D.

2003-07-22

A process for removing heavy metals from water is provided. The process includes the steps of introducing magnetite to a quantity of water containing heavy metal. The magnetite is mixed with the water such that at least a portion of, and preferably the majority of, the heavy metal in the water is bound to the magnetite. Once this occurs the magnetite and absorbed metal is removed from the water by application of a magnetic field. In most applications the process is achieved by flowing the water through a solid magnetized matrix, such as steel wool, such that the magnetite magnetically binds to the solid matrix. The magnetized matrix preferably has remnant magnetism, but may also be subject to an externally applied magnetic field. Once the magnetite and associated heavy metal is bound to the matrix, it can be removed and disposed of, such as by reverse water or air and water flow through the matrix. The magnetite may be formed in-situ by the addition of the necessary quantities of Fe(II) and Fe(III) ions, or pre-formed magnetite may be added, or a combination of seed and in-situ formation may be used. The invention also relates to an apparatus for performing the removal of heavy metals from water using the process outlined above.

Magnetic process for removing heavy metals from water employing magnetites

DOEpatents

Prenger, F. Coyne; Hill, Dallas D.

2006-12-26

A process for removing heavy metals from water is provided. The process includes the steps of introducing magnetite to a quantity of water containing heavy metal. The magnetite is mixed with the water such that at least a portion of, and preferably the majority of, the heavy metal in the water is bound to the magnetite. Once this occurs the magnetite and absorbed metal is removed from the water by application of a magnetic field. In most applications the process is achieved by flowing the water through a solid magnetized matrix, such as steel wool, such that the magnetite magnetically binds to the solid matrix. The magnetized matrix preferably has remnant magnetism, but may also be subject to an externally applied magnetic field. Once the magnetite and associated heavy metal is bound to the matrix, it can be removed and disposed of, such as by reverse water or air and water flow through the matrix. The magnetite may be formed in-situ by the addition of the necessary quantities of Fe(II) and Fe(III) ions, or pre-formed magnetite may be added, or a combination of seed and in-situ formation may be used. The invention also relates to an apparatus for performing the removal of heavy metals from water using the process outlined above.

Nematodes as bioindicators of soil degradation due to heavy metals.

PubMed

Šalamún, Peter; Renčo, Marek; Kucanová, Eva; Brázová, Tímea; Papajová, Ingrid; Miklisová, Dana; Hanzelová, Vladimíra

2012-11-01

The effect of distance from a heavy metal pollution source on the soil nematode community was investigated on four sampling sites along an 4 km transect originating at the Kovohuty a.s. Krompachy (pollution source). The soil nematode communities were exposed to heavy metal influence directly and through soil properties changes. We quantified the relative effects of total and mobile fraction of metals (As, Cd, Cr, Cu, Pb, and Zn) on soil ecosystem using the nematode community structure (trophic and c-p groups,) and ecological indices (Richness of genera, H', MI2-5, etc.). Pollution effects on the community structure of soil free living nematodes was found to be the highest near the pollution source, with relatively low population density and domination of insensitive taxa. A decrease in heavy metals contents along the transect was linked with an increase in complexity of nematode community. The majority of used indices (MI2-5, SI, H') negatively correlated (P < 0.05 or P < 0.01) with heavy metals content and were sensitive to soil ecosystem disturbance. Contamination by heavy metals has negatively affected the soil environment, which resulted in nematode community structure and ecological indices changes. Results showed that the free-living nematodes are useful tools for bioindication of contamination and could be used as an alternative to the common approaches based on chemical methods.

Assessment of heavy metals in loose deposits in drinking water distribution system.

PubMed

Liu, Quanli; Han, Weiqiang; Han, Bingjun; Shu, Min; Shi, Baoyou

2018-06-09

Heavy metal accumulation and potential releases from loose deposits in drinking water distribution system (DWDS) can have critical impacts on drinking water safety, but the associated risks have not been sufficiently evaluated. In this work, the potential biological toxicity of heavy metals in loose deposits was calculated based on consensus-based sediment quality guidelines, and the effects of some of the main water quality parameters, such as the pH and bicarbonate and phosphate content, on the release behaviors of pre-accumulated heavy metals were investigated. The results showed that heavy metals (Cu, As, Cr, Pb, and Cd) significantly accumulated in all the samples, but the contents of the heavy metals were multiple magnitudes lower than the Fe and Mn contents. The potential biotoxicity of As and Cu was relatively high, but the biotoxicity of Cd was negligible. The water quality can significantly influence the release of heavy metals from loose deposits. As the pH increased from 7.0 to 9.0, the release of As and Cr obviously increased. The release of As, Cu, Pb, and Cr also accelerated with the addition of phosphate (from 1 to 5 mg/L). In contrast to the trends for the pH and phosphate, variations in the bicarbonate content did not have a significant influence on the release of As and Cr. The release ratios of heavy metals in the samples were very low, and there was not a correlation between the release rate of the heavy metals in the loose deposits and their potential biotoxicity.

"Periodic-table-style" paper device for monitoring heavy metals in water.

PubMed

Li, Miaosi; Cao, Rong; Nilghaz, Azadeh; Guan, Liyun; Zhang, Xiwang; Shen, Wei

2015-03-03

If a paper-based analytical device (μ-PAD) could be made by printing indicators for detection of heavy metals in chemical symbols of the metals in a style of the periodic table of elements, it could be possible for such μ-PAD to report the presence and the safety level of heavy metal ions in water simultaneously and by text message. This device would be able to provide easy solutions to field-based monitoring of heavy metals in industrial wastewater discharges and in irrigating and drinking water. Text-reporting could promptly inform even nonprofessional users of the water quality. This work presents a proof of concept study of this idea. Cu(II), Ni(II), and Cr(VI) were chosen to demonstrate the feasibility, specificity, and reliability of paper-based text-reporting devices for monitoring heavy metals in water.

Body burdens of heavy metals in Lake Michigan wetland turtles.

PubMed

Smith, Dayna L; Cooper, Matthew J; Kosiara, Jessica M; Lamberti, Gary A

2016-02-01

Tissue heavy metal concentrations in painted (Chrysemys picta) and snapping (Chelydra serpentina) turtles from Lake Michigan coastal wetlands were analyzed to determine (1) whether turtles accumulated heavy metals, (2) if tissue metal concentrations were related to environmental metal concentrations, and (3) the potential for non-lethal sampling techniques to be used for monitoring heavy metal body burdens in freshwater turtles. Muscle, liver, shell, and claw samples were collected from painted and snapping turtles and analyzed for cadmium, chromium, copper, iron, lead, magnesium, manganese, and zinc. Turtle tissues had measurable quantities of all eight metals analyzed. Statistically significant correlations between tissue metal concentrations and sediment metal concentrations were found for a subset of metals. Metals were generally found in higher concentrations in the larger snapping turtles than in painted turtles. In addition, non-lethal samples of shell and claw were found to be possible alternatives to lethal liver and muscle samples for some metals. Human consumption of snapping turtles presents potential health risks if turtles are harvested from contaminated areas. Overall, our results suggest that turtles could be a valuable component of contaminant monitoring programs for wetland ecosystems.

[Heavy metals in environmental media around drinking water conservation area of Shanghai].

PubMed

Shi, Gui-Tao; Chen, Zhen-Lou; Zhang, Cui; Bi, Chun-Juan; Cheng, Chen; Teng, Ji-Yan; Shen, Jun; Wang, Dong-Qi; Xu, Shi-Yuan

2008-07-01

The levels of heavy metals in Shanghai drinking water conservation area were determined, and the spatial distributions and main sources of heavy metals were investigated. Moreover, the ecological risk assessment of heavy metals was conducted. Some conclusions can be drawn as follows: (1) The average concentrations of Cd, Hg, Pb, Cu, Zn, Ni, Cr and As in road dust were 0.80, 0.23, 148.45, 127.52, 380.57, 63.17, 250.38 and 10.37 mg x kg(-1) respectively. In terms of the pollution level, the values of soils were relatively lower, with the mean contents of 0.16 (Cd), 0.33 (Hg), 30.14 (Pb), 30.66 (Cu), 103.79 (Zn), 24.04 (Ni), 65.75 (Cr) and 6.31 mg x kg(-1) (As) severally; meanwhile the average levels of heavy metals in vegetables were 0.010 (Cd), 0.016 (Hg), 0.36 (Pb), 12.80 (Cu), 61.69 (Zn), 2.04 (Ni), 2.41 (Cr) and 0.039 mg x kg(-1) (As) respectively. (2) Semivariogram and multivariate analysis indicated that heavy metals pollution of soils was induced by anthropogenic activities mostly, and the pollutants produced by traffic were the major source of heavy metals in road dust. (3) The order for heavy metal enrichment coefficients of vegetables was as following: Zn (0.589) > Cu (0.412) > 0.102 (Ni) > Cd (0.059) > Cr (0.061) > Hg (0.056) > Pb (0.012) > As (0.007), and the results indicated that Cd and Zn in vegetables were mainly from the soils, and the other metals were probably from the pollutants in the atmosphere. (4) Sediments in drinking water conservation area were probably derived from soils around; however, there was no significant relationship between heavy metals contents of them. (5) The results of ecological risk assessment of heavy metals showed that heavy metals in soils were in no-warning to warning situation, and warning to light-warning situation for road dust and vegetables. The fuzzy synthesis judgment for all the environmental media around drinking water conservation area was warning to light-warning.

Neuromast hair cells retain the capacity of regeneration during heavy metal exposure.

PubMed

Montalbano, G; Capillo, G; Laurà, R; Abbate, F; Levanti, M; Guerrera, M C; Ciriaco, E; Germanà, A

2018-07-01

The neuromast is the morphological unit of the lateral line of fishes and is composed of a cluster of central sensory cells (hair cells) surrounded by support and mantle cells. Heavy metals exposure leads to disruption of hair cells within the neuromast. It is well known that the zebrafish has the ability to regenerate the hair cells after damage caused by toxicants. The process of regeneration depends on proliferation, differentiation and cellular migration of sensory and non-sensory progenitor cells. Therefore, our study was made in order to identify which cellular types are involved in the complex process of regeneration during heavy metals exposure. For this purpose, adult zebrafish were exposed to various heavy metals (Arsenic, cadmium and zinc) for 72h. After acute (24h) exposure, immunohistochemical localization of S100 (a specific marker for hair cells) in the neuromasts highlighted the hair cells loss. The immunoreaction for Sox2 (a specific marker for stem cells), at the same time, was observed in the support and mantle cells, after exposure to arsenic and cadmium, while only in the support cells after exposure to zinc. After chronic (72h) exposure the hair cells were regenerated, showing an immunoreaction for S100 protein. At the same exposure time to the three metals, a Sox2 immunoreaction was expressed in support and mantle cells. Our results showed for the first time the regenerative capacity of hair cells, not only after, but also during exposure to heavy metals, demonstrated by the presence of different stem cells that can diversify in hair cells. Copyright © 2018 Elsevier GmbH. All rights reserved.

Normal concentrations of heavy metals in autistic spectrum disorders.

PubMed

Albizzati, A; Morè, L; Di Candia, D; Saccani, M; Lenti, C

2012-02-01

Autism is a neurological-psychiatric disease. In the last 20 years we witnessed a strong increase of autism diagnoses. To explain this increase, some scientists put forward the hypothesis that heavy metal intoxication may be one of the causes of autism. The origin of such an intoxication was hypothesised to be vaccines containing thimerosal as antimicrobic preservative. This preservative is mainly made up of mercury. The aim of our research was to investigate the correlation between autism and high biological concentrations of heavy metals. Seventeen autistic patients, between 6 and 16 years old (average: 11.52 DS: 3.20) (15 males and 2 females), were investigated, as well as 20 non autistic subjects from neuropsychiatric service between 6 and 16 years (average: 10.41 DS: 3.20) (15 males and 2 females). In both groups blood, urine and hair samples were analysed trough means of a semiquantitative analysis of heavy metal dosing. The metals analysed were Lead, mercury, cadmium and aluminium, since their build-up may give both neurological and psychiatric symptoms. The comparison of the mean values of the concentrations between the groups, performed with ANOVA test, has shown no statistically relevant differences. There wasn't correlation between autism and heavy metal concentration.

[Transfer characteristic and source identification of soil heavy metals from water-level-fluctuating zone along Xiangxi River, three-Gorges Reservoir area].

PubMed

Xu, Tao; Wang, Fei; Guo, Qiang; Nie, Xiao-Qian; Huang, Ying-Ping; Chen, Jun

2014-04-01

Transfer characteristics of heavy metals and their evaluation of potential risk were studied based on determining concentration of heavy metal in soils from water-level-fluctuating zone (altitude:145-175 m) and bank (altitude: 175-185 m) along Xiangxi River, Three Gorges Reservoir area. Factor analysis-multiple linear regression (FA-MLR) was employed for heavy metal source identification and source apportionment. Results demonstrate that, during exposing season, the concentration of soil heavy metals in water-level-fluctuation zone and bank showed the variation, and the concentration of soil heavy metals reduced in shallow soil, but increased in deep soil at water-level-fluctuation zone. However, the concentration of soil heavy metals reduced in both shallow and deep soil at bank during the same period. According to the geoaccumulation index,the pollution extent of heavy metals followed the order: Cd > Pb > Cu > Cr, Cd is the primary pollutant. FA and FA-MLR reveal that in soils from water-level-fluctuation zone, 75.60% of Pb originates from traffic, 62.03% of Cd is from agriculture, 64.71% of Cu and 75.36% of Cr are from natural rock. In soils from bank, 82.26% of Pb originates from traffic, 68.63% of Cd is from agriculture, 65.72% of Cu and 69.33% of Cr are from natural rock. In conclusion, FA-MLR can successfully identify source of heavy metal and compute source apportionment of heavy metals, meanwhile the transfer characteristic is revealed. All these information can be a reference for heavy metal pollution control.

Transformation of heavy metal speciation during sludge drying: mechanistic insights

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

Weng, Huanxin; Ma, Xue-Wen; Fu, Feng-Xia

2014-01-30

Speciation can fundamentally affect on the stability and toxicity of heavy metals in sludge from wastewater treatment plants. This research investigated the speciation of heavy metals in sludge from both municipal and industrial sources, and metal speciation change as a result of drying process to reduce sludge volume. The changes in sludge properties including sludge moisture content, temperature, density, and electrical conductivity were also monitored to provide insights into the mechanisms causing the change in heavy metal speciation. The results show that the drying process generally stabilized the Cr, Cu, Cd and Pb in sludge by transforming acid-soluble, reducible andmore » oxidizable species into structurally stable forms. Such transformation and stabilization occurred regardless of the sludge source and type, and were primarily caused by the changes in sludge properties associated with decomposition of organic matter and sulfide. The results enhanced our understanding of the geochemical behavior of heavy metals in municipal sludge, and are useful for designing a treatment system for environment-friendly disposal of sludge.« less

Transformation of heavy metal speciation during sludge drying: mechanistic insights.

PubMed

Weng, Huan-Xin; Ma, Xue-Wen; Fu, Feng-Xia; Zhang, Jin-Jun; Liu, Zan; Tian, Li-Xun; Liu, Chongxuan

2014-01-30

Speciation can fundamentally affect on the stability and toxicity of heavy metals in sludge from wastewater treatment plants. This research investigated the speciation of heavy metals in sludge from both municipal and industrial sources, and metal speciation change as a result of drying process to reduce sludge volume. The changes in sludge properties including sludge moisture content, temperature, density, and electrical conductivity were also monitored to provide insights into the mechanisms causing the change in heavy metal speciation. The results show that the drying process generally stabilized Cr, Cu, Cd, and Pb in sludge by transforming acid-soluble, reducible, and oxidizable species into structurally stable forms. Such transformation and stabilization occurred regardless of the sludge source and type, and were primarily caused by the changes in sludge properties associated with decomposition of organic matter and sulfide. The results enhanced our understanding of the geochemical behavior of heavy metals in municipal sludge, and are useful for designing a treatment system for environment-friendly disposal of sludge. Copyright © 2013 Elsevier B.V. All rights reserved.

[Spatial variations of heavy metals in precipitation at Mount Taishan region].

PubMed

Wang, Yan; Liu, Xiao-Huan; Jin, Ling-Ren; Yue, Tai-Xing; Wang, De-Zhong; Wang, Wen-Xing

2007-11-01

Zn, Al, Mn, Fe, Pb, Cu, Ni, Cr, As, Cd in rain samples collected from two sites at Mount Taishan region were determined by ICP-MS, to evaluate the spatial variation characteristics of heavy metals in precipitation. Individual rain events were sampled for one whole year from Jan. to Dec. 2006. High concentrations of heavy metals were found at both sites, indicating serious heavy metal pollution. Zn was the most abundant element, accounting for 54% - 57% of the total metals concentrations. Its volume-weighted mean concentrations of precipitation at Mt-top and Mt-foot sites were 92.94 microg/L and 70.41 microg/L respectively. The following elements were Fe, Al and Mn and their concentrations were much higher than toxic heavy metals (As, Cd and Cd) except Pb (8.04 microg/L and 7.79 microg/L at two sites respectively). Comparison results between two sites suggested that heavy metal characteristics of precipitation at two sites were different, due to the influences of different ambient air conditions. Correlation analysis between two sites showed that Al, Mn, Fe, As, Cd, Pb influenced by air mass origin greatly, while Ni, Cu, Zn affected by other different factors.

Interactions between plant hormones and heavy metals responses

PubMed Central

Bücker-Neto, Lauro; Paiva, Ana Luiza Sobral; Machado, Ronei Dorneles; Arenhart, Rafael Augusto; Margis-Pinheiro, Marcia

2017-01-01

Abstract Heavy metals are natural non-biodegradable constituents of the Earth's crust that accumulate and persist indefinitely in the ecosystem as a result of human activities. Since the industrial revolution, the concentration of cadmium, arsenic, lead, mercury and zinc, amongst others, have increasingly contaminated soil and water resources, leading to significant yield losses in plants. These issues have become an important concern of scientific interest. Understanding the molecular and physiological responses of plants to heavy metal stress is critical in order to maximize their productivity. Recent research has extended our view of how plant hormones can regulate and integrate growth responses to various environmental cues in order to sustain life. In the present review we discuss current knowledge about the role of the plant growth hormones abscisic acid, auxin, brassinosteroid and ethylene in signaling pathways, defense mechanisms and alleviation of heavy metal toxicity. PMID:28399194

One-century sedimentary record of heavy metal pollution in western Taihu Lake, China.

PubMed

Li, Yan; Zhou, Shenglu; Zhu, Qing; Li, Baojie; Wang, Junxiao; Wang, Chunhui; Chen, Lian; Wu, Shaohua

2018-05-16

Long-term trends of sediment compositions are important for assessing the impact of human activities on the sediment and protecting the sediment environment. In this study, based on the contents of heavy metals and the Pb isotope ratios in lake sediments, atmospheric dustfall and soil in Yixing, China, the representative heavy metals (Zn, Pb, Cr and Cd) in lake sediments from western Taihu Lake were studied. The evolution history of heavy metals in the local environment was constructed for the past 100 years. From 1892 to the 1990s, the anthropogenic fluxes of the representative heavy metals were negligible, indicating minimal anthropogenic emissions of heavy metals. Since the 1990s, anthropogenic fluxes of the representative heavy metals began to increase, concurrent with the economic growth and development in the western Taihu Lake Basin after the Chinese economic reform. The maximum flux percentage of the heavy metals in the sediments, caused by human activities, is 23.0% for Zn, 31.6% for Pb, 39.5% for Cr and 85.3% for Cd, indicating that most of the Cd comes from human activities. The Cd content in the western Taihu Lake Basin was significantly higher than that in the other areas, and the rapid development of the industry in the western Taihu Lake Basin and ceramics in Yixing led to the enrichment of heavy metals in local sediments. Since the 21st century, measures have been taken to control the pollution of heavy metals, including the increase in local government attention and the deployment of environmental monitoring technology. However, heavy metal content remains high, and the Pb content is still increasing. The ratios of Pb isotopes show that the main sources of heavy metals in the western Taihu Lake sediments, the local soil of Yixing and the atmospheric dustfall are coal combustion, leaded gasoline combustion, industrial wastewater and domestic sewage. Copyright © 2018 Elsevier Ltd. All rights reserved.

Preparation of high density heavy metal fluoride glasses with extended ultraviolet and infra red ranges, and such high density heavy metal fluoride glasses

NASA Technical Reports Server (NTRS)

Martin, Steven W. (Inventor); Huebsch, Jesse (Inventor)

2001-01-01

A heavy metal fluoride glass composition range (in mol percent) consisting essentially of: (16-30)BaF.sub.2.(8-26)HfF.sub.4.(6-24)InF.sub.3 or GaF.sub.3.(4-16)CdF.sub.2.(6-24)YbF.sub.3.(4-22)ZnF.sub.2. In an alternative embodiment, a heavy metal fluoride glass composition range (in mol percent) comprises (16-30)BaF.sub.2.(8-26)HfF.sub.4.(6-24) of (0-24)InF.sub.3, (0-24)GaF.sub.3 and (0-19)AlF.sub.3.(1-16)CdF.sub.2.(6-24)YbF.sub.3.(4-26)ZnF.sub.2. A preferred heavy metal fluoride glass produced in accordance with the present invention comprises a composition (in mol %) and comprises about 26BaF.sub.2.18HfF.sub.4.7InF.sub.3.5GaF.sub.3.10CdF.sub.2.18YbF.sub.3. 16ZnF.sub.2. A preferred heavy metal fluoride glass has maximum thickness of most preferably about 3 mm. Another preferred heavy metal fluoride glass comprises a composition (in mol %) and comprises about 26BaF.sub.2.18HfF.sub.4.12AlF.sub.3.10CdF.sub.2.18YbF.sub.3.16ZnF.sub.2.

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.

[Immobilization impact of different fixatives on heavy metals contaminated soil].

PubMed

Wu, Lie-shan; Zeng, Dong-mei; Mo, Xiao-rong; Lu, Hong-hong; Su, Cui-cui; Kong, De-chao

2015-01-01

Four kinds of amendments including humus, ammonium sulfate, lime, superphosphate and their complex combination were added to rapid immobilize the heavy metals in contaminated soils. The best material was chosen according to the heavy metals' immobilization efficiency and the Capacity Values of the fixative in stabilizing soil heavy metals. The redistributions of heavy metals were determined by the European Communities Bureau of Referent(BCR) fraction distribution experiment before and after treatment. The results were as follows: (1) In the single material treatment, lime worked best with the dosage of 2% compared to the control group. In the compound amendment treatments, 2% humus combined with 2% lime worked best, and the immobilization efficiency of Pb, Cu, Cd, Zn reached 98.49%, 99.40%, 95.86%, 99.21%, respectively. (2) The order of Capacity Values was lime > humus + lime > ammonium sulfate + lime > superphosphate > ammonium sulfate + superphosphate > humus + superphosphate > humus > superphosphate. (3) BCR sequential extraction procedure results indicated that 2% humus combined with 2% lime treatment were very effective in immobilizing heavy metals, better than 2% lime treatment alone. Besides, Cd was activated firstly by 2% humus treatment then it could be easily changed into the organic fraction and residual fraction after the subsequent addition of 2% lime.

Heavy metal contamination in the Western Indian Ocean (a review)

NASA Astrophysics Data System (ADS)

Mamboya, F. A.; Pratap, H. B.; Björk, M.

2003-05-01

Western Indian Ocean Coast has many potential marine ecosystems such as mangrove, seagrass meadows, macroalgae, and coral reefs. It is largely unspoiled environment however, tourism and population growth in coastal urban centres, industrialization, are presenting a risk of pollutants input to the marine environment of the Western Indian Ocean. Mining, shipping and agricultural activities also input contaminants into the marine environment via runoff, vessel operations and accidental spillage. Heavy metals are among the pollutants that are expected to increase in the marine environment of the Western Indian Ocean. The increase in heavy metal pollution can pose a serious health problem to marine organism and human through food chain. This paper reviews studies on heavy metal contamination in the Western Indian Ocean. It covers heavy metal studies in the sediments, biota, particulates and seawater collected in different sites. In comparison to other regions, only few studies have been conducted in the Western Indian Ocean and are localized in some certain areas. Most of these studies were conducted in Kenyan and Tanzanian coasts while few of them were conducted in Mauritius, Somalia and Reunion. No standard or common method has been reported for the analysis or monitoring of heavy metals in the Western Indian Ocean.

Kinetics of heavy metal inhibition of 1,2-dichloroethane biodegradation in co-contaminated water.

PubMed

Arjoon, Ashmita; Olaniran, Ademola Olufolahan; Pillay, Balakrishna

2015-03-01

Sites co-contaminated with heavy metals and 1,2-DCA may pose a greater challenge for bioremediation, as the heavy metals could inhibit the activities of microbes involved in biodegradation. Therefore, this study was undertaken to quantitatively assess the effects of heavy metals (arsenic, cadmium, mercury, and lead) on 1,2-DCA biodegradation in co-contaminated water. The minimum inhibitory concentrations (MICs) and concentrations of the heavy metals that caused half-life doubling (HLDs) of 1,2-DCA as well as the degradation rate coefficient (k(1)) and half-life (t(½)) of 1,2-DCA were measured and used to predict the toxicity of the heavy metals in the water microcosms. An increase in heavy metal concentration resulted in a progressive increase in the t(½) and relative t(½) and a decrease in k(1). The MICs and HLDs of the heavy metals were found to vary, depending on the heavy metals type. In addition, the presence of heavy metals was shown to inhibit 1,2-DCA biodegradation in a dose-dependent manner, with the following order of decreasing inhibitory effect: Hg(2+)  > As(3+)  > Cd(2+)  > Pb(2+). Findings from this study have significant implications for the development of bioremediation strategies for effective degradation of 1,2-DCA and other related compounds in wastewater co-contaminated with heavy metals. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Soil heavy metal pollution and risk assessment associated with the Zn-Pb mining region in Yunnan, Southwest China.

PubMed

Cheng, Xianfeng; Danek, Tomas; Drozdova, Jarmila; Huang, Qianrui; Qi, Wufu; Zou, Liling; Yang, Shuran; Zhao, Xinliang; Xiang, Yungang

2018-03-07

The environmental assessment and identification of sources of heavy metals in Zn-Pb ore deposits are important steps for the effective prevention of subsequent contamination and for the development of corrective measures. The concentrations of eight heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in soils from 40 sampling points around the Jinding Zn-Pb mine in Yunnan, China, were analyzed. An environmental quality assessment of the obtained data was performed using five different contamination and pollution indexes. Statistical analyses were performed to identify the relations among the heavy metals and the pH in soils and possible sources of pollution. The concentrations of As, Cd, Pb, and Zn were extremely high, and 23, 95, 25, and 35% of the samples, respectively, exceeded the heavy metal limits set in the Chinese Environmental Quality Standard for Soils (GB15618-1995, grade III). According to the contamination and pollution indexes, environmental risks in the area are high or extremely high. The highest risk is represented by Cd contamination, the median concentration of which exceeds the GB15618-1995 limit. Based on the combination of statistical analyses and geostatistical mapping, we identified three groups of heavy metals that originate from different sources. The main sources of As, Cd, Pb, Zn, and Cu are mining activities, airborne particulates from smelters, and the weathering of tailings. The main sources of Hg are dust fallout and gaseous emissions from smelters and tailing dams. Cr and Ni originate from lithogenic sources.

In vitro susceptibility of spiroplasmas to heavy-metal salts.

PubMed

Whitmore, S C; Rissler, J F; Davis, R E

1983-01-01

The susceptibility of six spiroplasma strains to heavy-metal salt was characterized in terms of minimal inhibitory concentrations and minimal biocidal concentrations in broth tube dilution tests. The strains were most susceptible to mercuric chloride and silver nitrate; less susceptible to copper sulfate, cobalt chloride, lead nitrate, and cadmium sulfate; and least susceptible to nickel chloride and zinc sulfate. Spiroplasma citri strains Maroc R8A2 and C189 were the most susceptible to five of eight heavy-metal salts, and honeybee spiroplasma strain AS576 and Spiroplasma floricola strain 23-6 were generally the least susceptible. The difference between the minimal biocidal concentrations and the minimal inhibitory concentrations was greater for certain heavy-metal salts than for others.

Effects of sulfate on heavy metal release from iron corrosion scales in drinking water distribution system.

PubMed

Sun, Huifang; Shi, Baoyou; Yang, Fan; Wang, Dongsheng

2017-05-01

Trace heavy metals accumulated in iron corrosion scales within a drinking water distribution system (DWDS) could potentially be released to bulk water and consequently deteriorate the tap water quality. The objective of this study was to identify and evaluate the release of trace heavy metals in DWDS under changing source water conditions. Experimental pipe loops with different iron corrosion scales were set up to simulate the actual DWDS. The effects of sulfate levels on heavy metal release were systemically investigated. Heavy metal releases of Mn, Ni, Cu, Pb, Cr and As could be rapidly triggered by sulfate addition but the releases slowly decreased over time. Heavy metal release was more severe in pipes transporting groundwater (GW) than in pipes transporting surface water (SW). There were strong positive correlations (R 2  > 0.8) between the releases of Fe and Mn, Fe and Ni, Fe and Cu, and Fe and Pb. When switching to higher sulfate water, iron corrosion scales in all pipe loops tended to be more stable (especially in pipes transporting GW), with a larger proportion of stable constituents (mainly Fe 3 O 4 ) and fewer unstable compounds (β-FeOOH, γ-FeOOH, FeCO 3 and amorphous iron oxides). The main functional iron reducing bacteria (IRB) communities were favorable for the formation of Fe 3 O 4 . The transformation of corrosion scales and the growth of sulfate reducing bacteria (SRB) accounted for the gradually reduced heavy metal release with time. The higher metal release in pipes transporting GW could be due to increased Fe 6 (OH) 12 CO 3 content under higher sulfate concentrations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Heavy metal stabilization in contaminated road-derived sediments.

PubMed

Rijkenberg, Micha J A; Depree, Craig V

2010-02-01

There is increasing interest in the stabilization of heavy metals in road-derived sediments (RDS), to enable environmentally responsible reuse applications and circumvent the need for costly landfill disposal. To reduce the mobility of heavy metals (i.e. Cu, Pb and Zn) the effectiveness of amendments using phosphate, compost and fly ash addition were investigated using batch leaching experiments. In general, phosphate amendments of RDS were found to be ineffective at stabilizing heavy metals, despite being used successfully in soils. Phosphate amendment resulted in enhanced concentrations of dissolved organic carbon (DOC), which increased the solubilisation of heavy metals via complexation. Amendment with humified organic matter (compost) successfully stabilized Cu and Pb in high DOC leaching RDS with an optimum loading of 15-20% (w/w). Compost, however, was ineffective at stabilizing Zn. Increasing the pH by amending RDS/compost blends with 2.5-15% (w/w) coal fly ash resulted in the stabilization of Zn, Cu and Pb. However, above a pH of approximately 7.5 and 8 enhanced leaching of organic matter resulted in an increase in leached Cu and Pb, respectively. Accordingly, the optimum level of fly ash amendment for the RDS/compost blends was estimated to be ca. 10%. Boosted regression trees analysis (BRT) of the data revealed that DOC accounted for 56% and 65% of the Cu and Pb leaching, respectively, whereas pH only accounted for ca. 18% of Cu and Pb leaching. RDS sample characteristics (i.e. metal concentrations, size fractionation and organic matter content) were more important at reconciling the leaching concentrations of copper Cu (27%) than Pb (16%). The most important parameter explaining Zn leaching was pH. Overall, the choice of a suitable stabilization agent/s depends on the composition of RDS with respect to the amount of organic matter present, and the sorption chemistry of the heavy metal of interest. Copyright 2009 Elsevier B.V. All rights reserved.

Multivariate analysis of mixed contaminants (PAHs and heavy metals) at manufactured gas plant site soils.

PubMed

Thavamani, Palanisami; Megharaj, Mallavarapu; Naidu, Ravi

2012-06-01

Principal component analysis (PCA) was used to provide an overview of the distribution pattern of polycyclic aromatic hydrocarbons (PAHs) and heavy metals in former manufactured gas plant (MGP) site soils. PCA is the powerful multivariate method to identify the patterns in data and expressing their similarities and differences. Ten PAHs (naphthalene, acenapthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, benzo[a]pyrene) and four toxic heavy metals - lead (Pb), cadmium (Cd), chromium (Cr) and zinc (Zn) - were detected in the site soils. PAH contamination was contributed equally by both low and high molecular weight PAHs. PCA was performed using the varimax rotation method in SPSS, 17.0. Two principal components accounting for 91.7% of the total variance was retained using scree test. Principle component 1 (PC1) substantially explained the dominance of PAH contamination in the MGP site soils. All PAHs, except anthracene, were positively correlated in PC1. There was a common thread in high molecular weight PAHs loadings, where the loadings were inversely proportional to the hydrophobicity and molecular weight of individual PAHs. Anthracene, which was less correlated with other individual PAHs, deviated well from the origin which can be ascribed to its lower toxicity and different origin than its isomer phenanthrene. Among the four major heavy metals studied in MGP sites, Pb, Cd and Cr were negatively correlated in PC1 but showed strong positive correlation in principle component 2 (PC2). Although metals may not have originated directly from gaswork processes, the correlation between PAHs and metals suggests that the materials used in these sites may have contributed to high concentrations of Pb, Cd, Cr and Zn. Thus, multivariate analysis helped to identify the sources of PAHs, heavy metals and their association in MGP site, and thereby better characterise the site risk, which would not be possible if one uses chemical analysis

Interactions between heavy metals and photosynthetic materials studied by optical techniques.

PubMed

Ventrella, Andrea; Catucci, Lucia; Piletska, Elena; Piletsky, Sergey; Agostiano, Angela

2009-11-01

In this work studies on rapid inhibitory interactions between heavy metals and photosynthetic materials at different organization levels were carried out by optical assay techniques, investigating the possibility of applications in the heavy metal detection field. Spinach chloroplasts, thylakoids and Photosystem II proteins were employed as biotools in combination with colorimetric assays based on dichlorophenol indophenole (DCIP) photoreduction and on fluorescence emission techniques. It was found that copper and mercury demonstrated a strong and rapid photosynthetic activity inhibition, that varied from proteins to membranes, while other metals like nickel, cobalt and manganese produced only slight inhibition effects on all tested photosynthetic materials. By emission measurements, only copper was found to rapidly influence the photosynthetic material signals. These findings give interesting information about the rapid effects of heavy metals on isolated photosynthetic samples, and are in addition to the literature data concerning the effects of growth in heavy metal enriched media.

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

Mannosomes: a molluscan intracellular tubular membrane system related to heavy metal stress?

PubMed

Knigge, Thomas; Mann, Neelam; Parveen, Zahida; Perry, Christopher; Gernhöfer, Maike; Triebskorn, Rita; Köhler, Heinz R; Connock, Martin

2002-03-01

Amongst animals, several hydrogen peroxide-generating oxidases are apparently restricted to molluscs. One of these, D-mannitol oxidase, is concentrated in the alimentary system, where it is associated with its own subcellular membrane system of unique tubular morphology, most likely representing a structural modification of the ER. These structures can be purified by subcellular fractionation and have been termed 'mannosomes'. Little is known about the functions of mannitol oxidase or of mannosomes, but the previously reported molluscicide-induced increase in mannosomes implies their involvement in a general stress reaction. In this study, we examined the effects of heavy metal stress in the terrestrial gastropod Arion lusitanicus. The activity of mannitol oxidase and mannosome abundance were monitored, together with metal effects on heat-shock protein level, and these parameters were compared to heavy metal accumulation in the digestive gland. We found that mannitol oxidase is inhibited by heavy metals more than other oxidases. On the other hand, hsp70 levels and mannosomal protein were increased with enhanced heavy metal stress, the latter indicating a probable increase in the number of mannosome organelles. Thus, stress protein (hsp70) and mannosomal protein were positively correlated with heavy metal accumulation, whereas the enzyme activity showed a negative correlation with increasing heavy metal content of the slugs.

Heavy metals in the finest size fractions of road-deposited sediments.

PubMed

Lanzerstorfer, Christof

2018-08-01

The concentration of heavy metals in urban road-deposited sediments (RDS) can be used as an indicator for environmental pollution. Thus, their occurrence has been studied in whole road dust samples as well as in size fractions obtained by sieving. Because of the limitations of size separation by sieving little information is available about heavy metal concentrations in the road dust size fractions <20 μm. In this study air classification was applied for separation of dust size fractions smaller than 20 μm from RDS collected at different times during the year. The results showed only small seasonal variations in the heavy metals concentrations and size distribution. According to the Geoaccumulation Index the pollution of the road dust samples deceased in the following order: Sb » As > Cu ≈ Zn > Cr > Cd ≈ Pb ≈ Mn > Ni > Co ≈ V. For all heavy metals the concentration was higher in the fine size fractions compared to the coarse size fractions, while the concentration of Sr was size-independent. The enrichment of the heavy metals in the finest size fraction compared to the whole RDS <200 μm was up to 4.5-fold. The size dependence of the concentration decreased in the following order: Co ≈ Cd > Sb > (Cu) ≈ Zn ≈ Pb > As ≈ V » Mn. The approximation of the size dependence of the concentration as a function of the particle size by power functions worked very well. The correlation between particle size and concentration was high for all heavy metals. The increased heavy metals concentrations in the finest size fractions should be considered in the evaluation of the contribution of road dust re-suspension to the heavy metal contamination of atmospheric dust. Thereby, power functions can be used to describe the size dependence of the concentration. Copyright © 2018 Elsevier Ltd. All rights reserved.

[Evaluation of soil heavy metals accumulation in the fast economy development region].

PubMed

Zhong, Xian-Lan; Zhou, Sheng-Lu; Li, Jiang-Tao; Zhao, Qi-Guo

2010-06-01

Evaluation of soil heavy metals accumulation was studied in Kunshan City, a typical region of the fast economy development region in China. 126 soil samples were collected and analyzed, and evaluation indexes of soil heavy metal accumulation, which including total concentration of soil heavy metal index (THMI), soil available heavy metal index (AHMI) and fractionation of soil heavy metal index (FHMI), were established, and the heavy metal accumulation conditions of soil in this region were also discussed. Results showed as follows: the spatial variability of THMI was relative lower, with a mean value of 42.57%, whereas strong variability was found in AHMI and FHMI (especially active fraction of soil heavy metals), with the average value of 82.75% and 77.83%, respectively. Judging by each index reference standard of C Horizon, THMI was low-grade with a mean value of 1.01, while the AHMI and FHMI reached to medium accumulation and serious accumulation, with the average values of 2.46 and 4.32, respectively. The synthetic accumulation index of soil heavy metals (SHMI) was 2.56, reaching to medium grade level and with strong variability. 21.54% land area was in low-grade accumulation and 54.70% land area was in medium grade accumulation, while 23.76% land area was in serious accumulation under SHMI evaluation system. All the accumulation evaluation indexes in livestock breeding zone were the lowest, while the indexes in the smelting and plating zone were the highest, but the indexes difference between two zones were unobvious. There were markedly differences in soil types, which the accumulation indexes in Wushan soil were significantly higher than those in Huangni soil and Qingni soil.

Heavy metal resistant strains are widespread along Streptomyces phylogeny.

PubMed

Alvarez, Analía; Catalano, Santiago A; Amoroso, María Julia

2013-03-01

The genus Streptomyces comprises a group of bacteria species with high economic importance. Several of these species are employed at industrial scale for the production of useful compounds. Other characteristic found in different strains within this genus is their capability to tolerate high level of substances toxic for humans, heavy metals among them. Although several studies have been conducted in different species of the genus in order to disentangle the mechanisms associated to heavy metal resistance, little is known about how they have evolved along Streptomyces phylogeny. In this study we built the largest Streptomyces phylogeny generated up to date comprising six genes, 113 species of Streptomyces and 27 outgroups. The parsimony-based phylogenetic analysis indicated that (i) Streptomyces is monophyletic and (ii) it appears as sister clade of a group formed by Kitasatospora and Streptacidiphilus species, both genera also monophyletic. Streptomyces strains resistant to heavy metals are not confined to a single lineage but widespread along Streptomyces phylogeny. Our result in combination with genomic, physiological and biochemical data suggest that the resistance to heavy metals originated several times and by different mechanisms in Streptomyces history. Copyright © 2012 Elsevier Inc. All rights reserved.

Environmental monitoring and assessment of heavy metals in surface sediments at Coleroon River Estuary in Tamil Nadu, India.

PubMed

Venkatramanan, S; Chung, S Y; Ramkumar, T; Selvam, S

2015-08-01

The combined studies on grain size distribution, organic matter contents of sediments, sequential extraction and bulk concentration of heavy metals, statistical analysis, and ecological risk assessments were carried out to investigate the contamination sources and ecological risks of surface sediments at Coleroon River Estuary in Tamil Nadu, India. The sequential extraction of metals showed that a larger portion of the metals was associated with the residual phase and also in other fractions. The low concentrations of heavy metals were found in exchangeable and carbonate bounds (bioavailable phases). It revealed that sediments of Coleroon River Estuary were relatively unpolluted and were influenced mainly by natural sources. The observed order of bulk concentrations of heavy metals in the sediments was as follows: Fe > Mn > Zn > Cu > Pb > Cr > Ni > Co. Factor analyses represented that the enrichment of heavy metals was mostly resulted from lithogenic origins associated with anthropogenic sources. These sources were reconfirmed by cluster analysis. Risk assessment code (RAC) suggested that all metals were not harmful in monsoon season. However, Fe was in medium risk, and Mn and Cu were in low risk in summer. According to pollution load index (PLI) of sediments, all heavy metals were toxic. Cu might be related with adverse biological effects on the basis of sediment quality guidelines (SQG) in both seasons. These integrated approaches were very useful to identify the contamination sources and ecological risks of sediments in estuarine environment. It is expected that this research can give a useful information for the remediation of heavy metals in sediments.

Transcriptome Response to Heavy Metals in Sinorhizobium meliloti CCNWSX0020 Reveals New Metal Resistance Determinants That Also Promote Bioremediation by Medicago lupulina in Metal-Contaminated Soil.

PubMed

Lu, Mingmei; Jiao, Shuo; Gao, Enting; Song, Xiuyong; Li, Zhefei; Hao, Xiuli; Rensing, Christopher; Wei, Gehong

2017-10-15

The symbiosis of the highly metal-resistant Sinorhizobium meliloti CCNWSX0020 and Medicago lupulina has been considered an efficient tool for bioremediation of heavy metal-polluted soils. However, the metal resistance mechanisms of S. meliloti CCNWSX00200 have not been elucidated in detail. Here we employed a comparative transcriptome approach to analyze the defense mechanisms of S. meliloti CCNWSX00200 against Cu or Zn exposure. Six highly upregulated transcripts involved in Cu and Zn resistance were identified through deletion mutagenesis, including genes encoding a multicopper oxidase (CueO), an outer membrane protein (Omp), sulfite oxidoreductases (YedYZ), and three hypothetical proteins (a CusA-like protein, a FixH-like protein, and an unknown protein), and the corresponding mutant strains showed various degrees of sensitivity to multiple metals. The Cu-sensitive mutant (Δ cueO ) and three mutants that were both Cu and Zn sensitive (Δ yedYZ , Δ cusA -like, and Δ fixH -like) were selected for further study of the effects of these metal resistance determinants on bioremediation. The results showed that inoculation with the Δ cueO mutant severely inhibited infection establishment and nodulation of M. lupulina under Cu stress, while inoculation with the Δ yedYZ and Δ fixH -like mutants decreased just the early infection frequency and nodulation under Cu and Zn stresses. In contrast, inoculation with the Δ cusA -like mutant almost led to loss of the symbiotic capacity of M. lupulina to even grow in uncontaminated soil. Moreover, the antioxidant enzyme activity and metal accumulation in roots of M. lupulina inoculated with all mutants were lower than those with the wild-type strain. These results suggest that heavy metal resistance determinants may promote bioremediation by directly or indirectly influencing formation of the rhizobium-legume symbiosis. IMPORTANCE Rhizobium-legume symbiosis has been promoted as an appropriate tool for bioremediation of heavy

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

Mechanism of a strange metal state near a heavy-fermion quantum critical point

NASA Astrophysics Data System (ADS)

Chang, Yung-Yeh; Paschen, Silke; Chung, Chung-Hou

2018-01-01

Unconventional metallic or strange metal (SM) behavior with non-Fermi liquid (NFL) properties, generic features of heavy-fermion systems near quantum phase transitions, are yet to be understood microscopically. A paradigmatic example is the magnetic field-tuned quantum critical heavy-fermion metal YbRh2Si2 , revealing a possible SM state over a finite range of fields at low temperatures when substituted with Ge. Above a critical field, the SM state gives way to a heavy Fermi liquid with Kondo correlation. The NFL behavior, most notably a linear-in-temperature electrical resistivity and a logarithmic-in-temperature followed by a power-law singularity in the specific heat coefficient at low temperatures, still lacks a definite understanding. We propose the following mechanism as origin of the experimentally observed behavior: a quasi-2 d fluctuating short-ranged resonating-valence-bond spin liquid competing with the Kondo correlation. Applying a field-theoretical renormalization group analysis on an effective field theory beyond a large-N approach to an antiferromagnetic Kondo-Heisenberg model, we identify the critical point and explain remarkably well the SM behavior. Our theory goes beyond the well-established framework of quantum phase transitions and serves as a basis to address open issues in quantum critical heavy-fermion systems.

Comparative characterization of sewage sludge compost and soil: Heavy metal leaching characteristics.

PubMed

Fang, Wen; Wei, Yonghong; Liu, Jianguo

2016-06-05

The leaching and accumulation of heavy metals are major concerns following the land application of sewage sludge compost (SSC). We comparatively characterized SSC, the reference soil, and the SSC amended soil to investigate their similarities and differences regarding heavy metal leaching behavior and then to evaluate the effect of SSC land application on the leaching behavior of soil. Results showed that organic matter, including both of particulate organic matter (POM) and dissolved organic matter (DOM), were critical factors influencing heavy metal leaching from both of SSC and the soil. When SSC was applied to soil at the application rate of 48t/ha, the increase of DOM content slightly enhanced heavy metal leaching from the amended soil over the applicable pH domain (6heavy metals. The geochemical speciation modeling revealed that heavy metal speciation in the solid phase were similar between the reference soil and the amended soil. Copyright © 2016 Elsevier B.V. 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.

Extraction of Rice Phenological Differences under Heavy Metal Stress Using EVI Time-Series from HJ-1A/B Data.

PubMed

Liu, Shuyuan; Liu, Xiangnan; Liu, Meiling; Wu, Ling; Ding, Chao; Huang, Zhi

2017-05-30

An effective method to monitor heavy metal stress in crops is of critical importance to assure agricultural production and food security. Phenology, as a sensitive indicator of environmental change, can respond to heavy metal stress in crops and remote sensing is an effective method to detect plant phenological changes. This study focused on identifying the rice phenological differences under varied heavy metal stress using EVI (enhanced vegetation index) time-series, which was obtained from HJ-1A/B CCD images and fitted with asymmetric Gaussian model functions. We extracted three phenological periods using first derivative analysis: the tillering period, heading period, and maturation period; and constructed two kinds of metrics with phenological characteristics: date-intervals and time-integrated EVI, to explore the rice phenological differences under mild and severe stress levels. Results indicated that under severe stress the values of the metrics for presenting rice phenological differences in the experimental areas of heavy metal stress were smaller than the ones under mild stress. This finding represents a new method for monitoring heavy metal contamination through rice phenology.

A modified receptor model for source apportionment of heavy metal pollution in soil.

PubMed

Huang, Ying; Deng, Meihua; Wu, Shaofu; Japenga, Jan; Li, Tingqiang; Yang, Xiaoe; He, Zhenli

2018-07-15

Source apportionment is a crucial step toward reduction of heavy metal pollution in soil. Existing methods are generally based on receptor models. However, overestimation or underestimation occurs when they are applied to heavy metal source apportionment in soil. Therefore, a modified model (PCA-MLRD) was developed, which is based on principal component analysis (PCA) and multiple linear regression with distance (MLRD). This model was applied to a case study conducted in a peri-urban area in southeast China where soils were contaminated by arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb). Compared with existing models, PCA-MLRD is able to identify specific sources and quantify the extent of influence for each emission. The zinc (Zn)-Pb mine was identified as the most important anthropogenic emission, which affected approximately half area for Pb and As accumulation, and approximately one third for Cd. Overall, the influence extent of the anthropogenic emissions decreased in the order of mine (3 km) > dyeing mill (2 km) ≈ industrial hub (2 km) > fluorescent factory (1.5 km) > road (0.5 km). Although algorithm still needs to improved, the PCA-MLRD model has the potential to become a useful tool for heavy metal source apportionment in soil. Copyright © 2018 Elsevier B.V. All rights reserved.

Heavy metals in livers and kidneys of goats in Alabama

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

Khan, A.T.; Diffay, B.C.; Datiri, B.C.

1995-10-01

The popularity of goat farming is increasing in the southeastern region of the United States. Baseline values of Hg, Pb, and Cd are not available in goat tissues in the United States. These values are needed when monitoring food for heavy metal contamination which may be associated with urbanization and industrialization. Due to human activities or anthropogenic sources of metals in the environment, high concentrations of these metals have been observed in herbage and animal tissues. It has also been reported that toxic heavy metals are concentrated mostly in kidneys and livers of animals. The risk of exposure of humansmore » to heavy metals contained in edible organs of animals has received widespread concern. The objectives of this study were to (i) measure the levels of Hg,Pb, and Cd in livers and kidneys of goats; and (ii) determine whether accumulation of these metals is related to age and/or sex. 20 refs., 3 tabs.« less

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.

Pyrolysis and reutilization of plant residues after phytoremediation of heavy metals contaminated sediments: For heavy metals stabilization and dye adsorption.

PubMed

Gong, Xiaomin; Huang, Danlian; Liu, Yunguo; Zeng, Guangming; Wang, Rongzhong; Wei, Jingjing; Huang, Chao; Xu, Piao; Wan, Jia; Zhang, Chen

2018-04-01

This study aimed to investigate the effect of pyrolysis on the stabilization of heavy metals in plant residues obtained after phytoremediation. Ramie residues, being collected after phytoremediation of metal contaminated sediments, were pyrolyzed at different temperatures (300-700 °C). Results indicated that pyrolysis was effective in the stabilization of Cd, Cr, Zn, Cu, and Pb in ramie residues by converting the acid-soluble fraction of metals into residual form and decreasing the TCLP-leachable metal contents. Meanwhile, the reutilization potential of using the pyrolysis products generated from ramie residues obtained after phytoremediation as sorbents was investigated. Adsorption experiments results revealed that the pyrolysis products presented excellent ability to adsorb methylene blue (MB) with a maximum adsorption capacity of 259.27 mg/g. This study demonstrated that pyrolysis could be used as an efficient alternative method for stabilizing heavy metals in plant residues obtained after phytoremediation, and their pyrolysis products could be reutilized for dye adsorption. Copyright © 2018 Elsevier Ltd. All rights reserved.

Mussel Shell Evaluation as Bioindicator For Heavy Metals

NASA Astrophysics Data System (ADS)

Andrello, Avacir Casanova; Lopes, Fábio; Galvão, Tiago Dutra

2010-05-01

Recently, in Brazil, it has appeared a new and unusual "plague" in lazer and commercial fishing. It is caused by the parasitic larval phase of certain native bivalve mollusks of fresh water known as "Naiades" and its involves the presence of big bivalve of fresh water, mainly Anodontites trapesialis, in the tanks and dams of the fish creation. These bivalve mollusks belong to the Unionoida Order, Mycetopodidae Family. The objective of the present work was to analyze the shells of these mollusks to verify the possibility of use as bioindicators for heavy metals in freshwater. The mollusks shells were collected in a commercial fishing at Londrina-PR. A qualitative analysis was made to determine the chemical composition of the shells and verify a possible correlation with existent heavy metals in the aquatic environment. In the inner part of the shells were identified the elements Ca, P, Fe, Mn and Sr and in the outer part were identified Ca, P, Fe, Mn, Sr and Cu. The Ca ratio of the outer part by inner part of the analyzed shells is around of 1, as expected, because Ca is the main compound of mollusks shells. The ratio of P, Fe, Mn, and Sr to the Ca were constant in all analyzed shells, being close to 0.015. The ratio Cu/Ca varied among the shells, showing that this mollusk is sensitive to concentration of this element in the aquatic environment.

Thermodynamics of binding interactions between extracellular polymeric substances and heavy metals by isothermal titration microcalorimetry.

PubMed

Yan, Peng; Xia, Jia-Shuai; Chen, You-Peng; Liu, Zhi-Ping; Guo, Jin-Song; Shen, Yu; Zhang, Cheng-Cheng; Wang, Jing

2017-05-01

Extracellular polymeric substances (EPS) play a crucial role in heavy metal bio-adsorption using activated sludge, but the interaction mechanism between heavy metals and EPS remains unclear. Isothermal titration calorimetry was employed to illuminate the mechanism in this study. The results indicate that binding between heavy metals and EPS is spontaneous and driven mainly by enthalpy change. Extracellular proteins in EPS are major participants in the binding process. Environmental conditions have significant impact on the adsorption performance. Divalent and trivalent cations severely impeded the binding of heavy metal ions to EPS. Electrostatic interaction mainly attributed to competition between divalent cations and heavy metal ions; trivalent cations directly competed with heavy metal ions for EPS binding sites. Trivalent cations were more competitive than divalent cations for heavy metal ion binding because they formed complexing bonds. This study facilitates a better understanding about the interaction between heavy metals and EPS in wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of heavy metal pollution on enzyme activities in railway cut slope soils.

PubMed

Meng, Xiaoyi; Ai, Yingwei; Li, Ruirui; Zhang, Wenjuan

2018-03-07

Railway transportation is an important transportation mode. However, railway transportation causes heavy metal pollution in surrounding soils. Heavy metal pollution has a serious negative impact on the natural environment, including a decrease of enzyme activities in soil and degradation of sensitive ecosystems. Some studies investigated the heavy metal pollution at railway stations or certain transportation hubs. However, the pollution accumulated in artificial cut slope soil all along the rails is still questioned. The interest on non-point source pollution from railways is increasing in an effort to protect the soil quality along the line. In this study, we studied spatial distributions of heavy metals and five enzyme activities, i.e., urease (UA), saccharase (SAC), protease (PRO), catalase (CAT), and polyphenol oxidase (POA) in the soil, and the correlation among them beside three different railways in Sichuan Province, China, as well. Soil samples were respectively collected from 5, 10, 25, 50, 100, and 150 m away from the rails (depth of 0-8 cm). Results showed that Mn, Cd, Cu, and Zn were influenced by railway transportation in different degrees while Pb was not. Heavy metal pollution was due to the abrasion of the gravel bed as well as the tracks and freight transportation which caused more heavy metal pollution than passenger transportation. Enzymatic activities were significantly negatively correlated with heavy metals in soils, especially Zn and Cu. Finally, it is proposed that combined use of PRO and POA activities could be an indicator of the heavy metal pollution in cut slope soils. The protective measures aimed at heavy metal pollution caused by railway transportation in cut slope soils are urgent.

Quantum dot impregnated-chitosan film for heavy metal ion sensing and removal.

PubMed

Jaiswal, Amit; Ghsoh, Siddhartha Sankar; Chattopadhyay, Arun

2012-11-06

We report the use of biopolymer-stabilized ZnS quantum dots (Q-dots) for cation exchange reaction-based easy sensing and removal of heavy metal ions such as Hg(2+), Ag(+), and Pb(2+) in water. Chitosan-stabilized ZnS Q-dots were synthesized in aqueous medium and were observed to have been converted to HgS, Ag(2)S, and PbS Q-dots in the presence of corresponding ions. The transformed Q-dots showed characteristic color development, with Hg(2+) being exceptionally identifiable due to the visible bright yellow color formation, while brown coloration was observed in other metal ions. The cation exchange was driven by the difference in the solubility product of the reactant and the product Q-dots. The cation exchanged Q-dots preserved the morphology of the reactant Q-dots and displayed volume increase based on the bulk crystal lattice parameters. The band gap of the transformed Q-dots showed a major increase from the corresponding bulk band gap of the material, demonstrating the role of quantum confinement. Next, we fabricated ZnS Q-dot impregnated chitosan film which was used to remove heavy metal ions from contaminated water as measured using atomic absorption spectroscopy (AAS). The present system could suitably be used as a simple dipstick for elimination of heavy metal ion contamination in water.

Estimation of Heavy Metal Contamination in Groundwater and Development of a Heavy Metal Pollution Index by Using GIS Technique.

PubMed

Tiwari, Ashwani Kumar; Singh, Prasoon Kumar; Singh, Abhay Kumar; De Maio, Marina

2016-04-01

Heavy metal (Al, As, Ba, Cr, Cu, Fe, Mn, Ni, Se and Zn) concentration in sixty-six groundwater samples of the West Bokaro coalfield were analyzed using inductively coupled plasma-mass spectroscopy for determination of seasonal fluctuation, source apportionment and heavy metal pollution index (HPI). Metal concentrations were found higher in the pre-monsoon season as compared to the post-monsoon season. Geographic information system (GIS) tool was attributed to study the metals risk in groundwater of the West Bokaro coalfield. The results show that 94 % of water samples were found as low class and 6 % of water samples were in medium class in the post-monsoon season. However, 79 % of water samples were found in low class, 18 % in medium class and 3 % in high class in the pre-monsoon season. The HPI values were below the critical pollution index value of 100. The concentrations of Al, Fe, Mn, and Ni are exceeding the desirable limits in many groundwater samples in both seasons.

Heavy metal speciation and risk assessment in dry land and paddy soils near mining areas at Southern China.

PubMed

Liu, Guannan; Wang, Juan; Zhang, Erxi; Hou, Jing; Liu, Xinhui

2016-05-01

Heavy metal contamination of soils has been a long-standing environmental problem in many parts of the world, and poses enormous threats to ecosystem and human health. Speciation of heavy metals in soils is crucial to assessing environmental risks from contaminated soils. In this study, total concentrations and speciation of As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn were measured for agricultural soils near mines along the Diaojiang River in Guangxi Zhuang Autonomy Region, China. The sources of heavy metals in soils also were identified to assess their effect on speciation distribution of soil heavy metals. Furthermore, the speciation distribution of Cd and Zn, main soil heavy metal pollutants, in dry land and paddy soils were compared. Results showed that there were two severely polluted regions near mine area reaching alarming pollution level. As, Cd, Pb, and Zn were more affected by mining activities, showing very strong pollution level in soils. The mean percentage of exchangeable and carbonate fraction was highest and up to 46.8 % for Cd, indicating a high environmental risk. Greater bioavailable fractions of As, Cd, Cu, Mn, Pb, and Zn were found in soils heavily polluted by mining activities, whereas Cr and Ni as geogenic elements in the stable residual fraction. In addition, in the dry land soils, reducible fraction proportion of Cd was higher than that in the paddy soils, whereas exchangeable and carbonate fraction of Cd was lower than that in the paddy soils. Oxidizable fraction of Zn was higher in the paddy soils than that in the dry land soils. The results indicate that the sources of soil heavy metals and land types affect heavy metal speciation in the soil and are significant for environmental risk assessment of soil heavy metal pollutions.

The impact of seasonal varied human activity on characteristics and sources of heavy metals in metropolitan road dusts.

PubMed

Men, Cong; Liu, Ruimin; Wang, Qingrui; Guo, Lijia; Shen, Zhenyao

2018-10-01

Due to significant human activity, road dust is becoming contaminated by heavy metals in many cities. To comprehensively investigate the variation of contamination level and sources of heavy metals in road dust, 10 heavy metals in road dust samples from Beijing, China, in both summer and winter, were evaluated by spatial analysis using geographic information system (GIS) mapping technology and the positive matrix factorization (PMF) Model. Although the concentrations of some heavy metals between summer and winter had similarities, the differences of others and spatial distributions of heavy metals between summer and winter were considerable. The mean concentrations of As, Cd, Cr, Cu, and Fe were lower in winter, while those of Hg, Mn, Ni, Pb, and Zn were higher. According to the values of the Pollution Index (PI) and Nemerow Integrated Pollution Index (NIPI), there were no obvious differences between summer and winter, but the range between different sites in winter was nearly twice that of summer. Based on the PMF model, four sources of heavy metals in the dust samples were identified. Although the types of sources were consistent, the relative contributions of each source differed between summer and winter. Non-exhaust vehicle emissions was the most important source in summer (34.47 wt%), while fuel combustion contributed the largest proportion to the total heavy metals in winter (32.40 wt%). The impact of each source also showed spatial variation different trends in summer and winter. With the alteration of seasons, intensity of human activities also changed, such as the number of tourists, energy needs for building temperature regulation, construction, and the amount of pesticides and fertilizer. That might be the reason for the variation of heavy metal concentrations and relative contribution of their sources between summer and winter. Copyright © 2018 Elsevier B.V. All rights reserved.

Assessment of heavy metal pollution in surface soils of urban parks in Beijing, China.

PubMed

Chen, Tong-Bin; Zheng, Yuan-Ming; Lei, Mei; Huang, Ze-Chun; Wu, Hong-Tao; Chen, Huang; Fan, Ke-Ke; Yu, Ke; Wu, Xiao; Tian, Qin-Zheng

2005-07-01

Assessing the concentration of potentially harmful heavy metals in the soil of urban parks is imperative in order to evaluate the potential risks to residents and tourists. To date, little research on soil pollution in China's urban parks has been conducted. To identify the concentrations and sources of heavy metals, and to assess the soil environmental quality, samples were collected from 30 urban parks located in the city of Beijing. Subsequently, the concentrations of Cu, Ni, Pb and Zn in the samples were analyzed. The investigation revealed that the accumulations of Cu and Pb were readily apparent in the soils. The integrated pollution index (IPI) of these four metals ranged from 0.97 to 9.21, with the highest IPI in the densely populated historic center district (HCD). Using multivariate statistic approaches (principal components analysis and hierarchical cluster analysis), two factors controlling the heavy metal variability were obtained, which accounted for nearly 80% of the total variance. Nickel and Zn levels were controlled by parent material in the soils, whereas Cu, Pb and, in part, Zn were accounted for mainly by anthropogenic activities. The findings presented here indicate that the location and the age of the park are important factors in determining the extent of heavy metal, particularly Cu and Pb, pollution. In addition, the accumulation of Zn did not appear to reach pollution levels, and no obvious pollution by Ni was observed in the soils of the parks in Beijing.

Physiological and Metagenomic Analyses of Microbial Mats Involved in Self-Purification of Mine Waters Contaminated with Heavy Metals

PubMed Central

Drewniak, Lukasz; Krawczyk, Pawel S.; Mielnicki, Sebastian; Adamska, Dorota; Sobczak, Adam; Lipinski, Leszek; Burec-Drewniak, Weronika; Sklodowska, Aleksandra

2016-01-01

Two microbial mats found inside two old (gold and uranium) mines in Zloty Stok and Kowary located in SW Poland seem to form a natural barrier that traps heavy metals leaking from dewatering systems. We performed complex physiological and metagenomic analyses to determine which microorganisms are the main driving agents responsible for self-purification of the mine waters and identify metabolic processes responsible for the observed features. SEM and energy dispersive X-ray microanalysis showed accumulation of heavy metals on the mat surface, whereas, sorption experiments showed that neither microbial mats were completely saturated with heavy metals present in the mine waters, indicating that they have a large potential to absorb significant quantities of metal. The metagenomic analysis revealed that Methylococcaceae and Methylophilaceae families were the most abundant in both communities, moreover, it strongly suggest that backbones of both mats were formed by filamentous bacteria, such as Leptothrix, Thiothrix, and Beggiatoa. The Kowary bacterial community was enriched with the Helicobacteraceae family, whereas the Zloty Stok community consist mainly of Sphingomonadaceae, Rhodobacteraceae, and Caulobacteraceae families. Functional (culture-based) and metagenome (sequence-based) analyses showed that bacteria involved in immobilization of heavy metals, rather than those engaged in mobilization, were the main driving force within the analyzed communities. In turn, a comparison of functional genes revealed that the biofilm formation and heavy metal resistance (HMR) functions are more desirable in microorganisms engaged in water purification than the ability to utilize heavy metals in the respiratory process (oxidation-reduction). These findings provide insight on the activity of bacteria leading, from biofilm formation to self-purification, of mine waters contaminated with heavy metals. PMID:27559332

Heavy Metal Concentrations in Soils and Factors Affecting Metal Uptake by Plants in the Vicinity of a Korean Cu-W Mine.

PubMed

Jung, Myung Chae

2008-04-04

Heavy metal concentrations were measured in soils and plants in and around a copper-tungsten mine in southeast Korea to investigate the influence of past base metal mining on the surface environment. The results of chemical analysis indicate that the heavy metals in soils decreased with distance from the source, controlled mainly by water movement and topography. The metal concentrations measured in plant species generally decreased in the order; spring onions > soybean leaves > perilla leaves » red pepper > corn grains » jujube grains, although this pattern varied moderately between different elements. The results agree with other reports that metal concentrations in leaves are usually much higher than those in grain. Factors influencing the bioavailability of metals and their occurrences in crops were found as soil pH, cation exchange capacity, organic matter content, soil texture, and interaction among the target elements. It is concluded that total metal concentrations in soils are the main controls on their contents in plants. Soil pH was also an important factor. A stepwise linear multiple regression analysis was also conducted to identify the dominant factors influencing metal uptake by plants. Metal concentrations in plants were also estimated by computer-aided statistical methods.

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

Deriving the Characteristic Scale for Effectively Monitoring Heavy Metal Stress in Rice by Assimilation of GF-1 Data with the WOFOST Model

PubMed Central

Huang, Zhi; Liu, Xiangnan; Jin, Ming; Ding, Chao; Jiang, Jiale; Wu, Ling

2016-01-01

Accurate monitoring of heavy metal stress in crops is of great importance to assure agricultural productivity and food security, and remote sensing is an effective tool to address this problem. However, given that Earth observation instruments provide data at multiple scales, the choice of scale for use in such monitoring is challenging. This study focused on identifying the characteristic scale for effectively monitoring heavy metal stress in rice using the dry weight of roots (WRT) as the representative characteristic, which was obtained by assimilation of GF-1 data with the World Food Studies (WOFOST) model. We explored and quantified the effect of the important state variable LAI (leaf area index) at various spatial scales on the simulated rice WRT to find the critical scale for heavy metal stress monitoring using the statistical characteristics. Furthermore, a ratio analysis based on the varied heavy metal stress levels was conducted to identify the characteristic scale. Results indicated that the critical threshold for investigating the rice WRT in monitoring studies of heavy metal stress was larger than 64 m but smaller than 256 m. This finding represents a useful guideline for choosing the most appropriate imagery. PMID:26959033

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

Regional probabilistic risk assessment of heavy metals in different environmental media and land uses: An urbanization-affected drinking water supply area

NASA Astrophysics Data System (ADS)

Peng, Chi; Cai, Yimin; Wang, Tieyu; Xiao, Rongbo; Chen, Weiping

2016-11-01

In this study, we proposed a Regional Probabilistic Risk Assessment (RPRA) to estimate the health risks of exposing residents to heavy metals in different environmental media and land uses. The mean and ranges of heavy metal concentrations were measured in water, sediments, soil profiles and surface soils under four land uses along the Shunde Waterway, a drinking water supply area in China. Hazard quotients (HQs) were estimated for various exposure routes and heavy metal species. Riverbank vegetable plots and private vegetable plots had 95th percentiles of total HQs greater than 3 and 1, respectively, indicating high risks of cultivation on the flooded riverbank. Vegetable uptake and leaching to groundwater were the two transfer routes of soil metals causing high health risks. Exposure risks during outdoor recreation, farming and swimming along the Shunde Waterway are theoretically safe. Arsenic and cadmium were identified as the priority pollutants that contribute the most risk among the heavy metals. Sensitivity analysis showed that the exposure route, variations in exposure parameters, mobility of heavy metals in soil, and metal concentrations all influenced the risk estimates.

Attrition resistant catalysts and sorbents based on heavy metal poisoned FCC catalysts

DOEpatents

Gangwal, S.; Jothimurugesan, K.

1999-07-27

A heavy metal poisoned, spent FCC catalyst is treated by chemically impregnating the poisoned catalyst with a new catalytic metal or metal salt to provide an attrition resistant catalyst or sorbent for a different catalytic or absorption process, such as catalysts for Fischer-Tropsh Synthesis, and sorbents for removal of sulfur gases from fuel gases and flue-gases. The heavy metal contaminated FCC catalyst is directly used as a support for preparing catalysts having new catalytic properties and sorbents having new sorbent properties, without removing or passivating the heavy metals on the spent FCC catalyst as an intermediate step.

Attrition resistant catalysts and sorbents based on heavy metal poisoned FCC catalysts

DOEpatents

Gangwal, Santosh; Jothimurugesan, Kandaswamy

1999-01-01

A heavy metal poisoned, spent FCC catalyst is treated by chemically impregnating the poisoned catalyst with a new catalytic metal or metal salt to provide an attrition resistant catalyst or sorbent for a different catalytic or absorption processes, such as catalysts for Fischer-Tropsh Synthesis, and sorbents for removal of sulfur gasses from fuel gases and flue-gases. The heavy metal contaminated FCC catalyst is directly used as a support for preparing catalysts having new catalytic properties and sorbents having new sorbent properties, without removing or "passivating" the heavy metals on the spent FCC catalyst as an intermediate step.

Potential of siderophore-producing bacteria for improving heavy metal phytoextraction.

PubMed

Rajkumar, Mani; Ae, Noriharu; Prasad, Majeti Narasimha Vara; Freitas, Helena

2010-03-01

Phytoremediation holds promise for in situ treatment of heavy metal contaminated soils. Recently, the benefits of combining siderophore-producing bacteria (SPB) with plants for metal removal from contaminated soils have been demonstrated. Metal-resistant SPB play an important role in the successful survival and growth of plants in contaminated soils by alleviating the metal toxicity and supplying the plant with nutrients, particularly iron. Furthermore, bacterial siderophores are able to bind metals other than iron and thus enhance their bioavailability in the rhizosphere of plants. Overall, an increase in plant growth and metal uptake will further enhance the effectiveness of phytoremediation processes. Here, we highlight the diversity and ecology of metal resistant SPB and discuss their potential role in phytoremediation 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

Comparative Analysis of GF-1 and HJ-1 Data to Derive the Optimal Scale for Monitoring Heavy Metal Stress in Rice.