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Sample records for chemical composition toxicity

  1. Metal Oxide Nanoparticles: The Importance of Size, Shape, Chemical Composition, and Valence State in Determining Toxicity

    NASA Astrophysics Data System (ADS)

    Dunnick, Katherine

    Nanoparticles, which are defined as a structure with at least one dimension between 1 and 100 nm, have the potential to be used in a variety of consumer products due to their improved functionality compared to similar particles of larger size. Their small size is associated with increased strength, improved catalytic properties, and increased reactivity; however, their size is also associated with increased toxicity in vitro and in vivo. Numerous toxicological studies have been conducted to determine the properties of nanomaterials that increase their toxicity in order to manufacture new nanomaterials with decreased toxicity. Data indicates that size, shape, chemical composition, and valence state of nanomaterials can dramatically alter their toxicity profile. Therefore, the purpose of this dissertation was to determine how altering the shape, size, and chemical composition of various metal oxide nanoparticles would affect their toxicity. Metal oxides are used in variety of consumer products, from spray-sun screens, to food coloring agents; thus, understanding the toxicity of metal oxides and determining which aspects affect their toxicity may provide safe alternatives nanomaterials for continued use in manufacturing. Tungstate nanoparticles toxicity was assessed in an in vitro model using RAW 264.7 cells. The size, shape, and chemical composition of these nanomaterials were altered and the effect on reactive oxygen species and general cytotoxicity was determined using a variety of techniques. Results demonstrate that shape was important in reactive oxygen species production as wires were able to induce significant reactive oxygen species compared to spheres. Shape, size, and chemical composition did not have much effect on the overall toxicity of these nanoparticles in RAW 264.7 cells over a 72 hour time course, implicating that the base material of the nanoparticles was not toxic in these cells. To further assess how chemical composition can affect toxicity

  2. Software for analysis of chemical mixtures--composition, occurrence, distribution, and possible toxicity

    USGS Publications Warehouse

    Scott, Jonathon C.; Skach, Kenneth A.; Toccalino, Patricia L.

    2013-01-01

    The composition, occurrence, distribution, and possible toxicity of chemical mixtures in the environment are research concerns of the U.S. Geological Survey and others. The presence of specific chemical mixtures may serve as indicators of natural phenomena or human-caused events. Chemical mixtures may also have ecological, industrial, geochemical, or toxicological effects. Chemical-mixture occurrences vary by analyte composition and concentration. Four related computer programs have been developed by the National Water-Quality Assessment Program of the U.S. Geological Survey for research of chemical-mixture compositions, occurrences, distributions, and possible toxicities. The compositions and occurrences are identified for the user-supplied data, and therefore the resultant counts are constrained by the user’s choices for the selection of chemicals, reporting limits for the analytical methods, spatial coverage, and time span for the data supplied. The distribution of chemical mixtures may be spatial, temporal, and (or) related to some other variable, such as chemical usage. Possible toxicities optionally are estimated from user-supplied benchmark data. The software for the analysis of chemical mixtures described in this report is designed to work with chemical-analysis data files retrieved from the U.S. Geological Survey National Water Information System but can also be used with appropriately formatted data from other sources. Installation and usage of the mixture software are documented. This mixture software was designed to function with minimal changes on a variety of computer-operating systems. To obtain the software described herein and other U.S. Geological Survey software, visit http://water.usgs.gov/software/.

  3. Relative toxicity of pyrolysis gases from materials - Effects of chemical composition and test conditions

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Cumming, H. J.

    1978-01-01

    Relative toxicity test data on 270 materials are presented, based on test procedures developed at the University of San Francisco. The effects of chemical composition, using data on 13 types of synthetic polymers and eight types of fabrics, are discussed. Selected materials were evaluated using nine test conditions with the USF method, and using methods developed at the FAA Civil Aeromedical Institute, Douglas Aircraft Company and San Jose State University.

  4. Chemical composition, protoscolicidal effects and acute toxicity of Pistacia atlantica Desf. fruit extract.

    PubMed

    Mahmoudvand, Hossein; Kheirandish, Farnaz; Ghasemi Kia, Mehdi; Tavakoli Kareshk, Amir; Yarahmadi, Mohammad

    2016-01-01

    The present study was designed to evaluate the chemical composition and scolicidal effects of Pistacia atlantica Desf. extract against protoscoleces of hydatid cysts and its acute toxicity in mice model. Various concentrations of the methanolic extract (5-50 mg/mL) were used for 10-60 min. Viability of protoscoleces was confirmed using eosin exclusion test (0.1%). Acute toxicity was also determined in mice model. The main components were β-myrcene (41.4%), α-pinene (32.48%) and limonene (4.66%). Findings demonstrated that P. atlantica extract at the concentrations of 25 and 50 mg/mL after 20 and 10 min of exposure killed 100% protoscoleces. The LD50 of the intraperitoneal injection of the P. atlantica methanolic extract was 2.43 g/kg and the maximum non-fatal dose was 1.66 g/kg. Obtained results showed the potential of P. atlantica extract as a natural source with no significant toxicity for the production of new scolicidal agent to use in hydatid cyst surgery. PMID:26252652

  5. Aerosols near by a coal fired thermal power plant: chemical composition and toxic evaluation.

    PubMed

    Jayasekher, T

    2009-06-01

    Industrial processes discharge fine particulates containing organic as well as inorganic compounds into the atmosphere which are known to induce damage to cell and DNA, both in vitro and in vivo. Source and area specific studies with respect to the chemical composition, size and shape of the particles, and toxicity evaluations are very much limited. This study aims to investigate the trace elements associated with the aerosol particles distributed near to a coal burning thermal power plant and to evaluate their toxicity through Comet assay. PM(10) (particles determined by mass passing an inlet with a 50% cut-off efficiency having a 10-microm aerodynamic diameter) samples were collected using respirable dust samplers. Twelve elements (Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb, Se, Hg, and As) were analyzed using ICP-AES. Comet assay was done with the extracts of aerosols in phosphate buffered saline (PBS). Results show that Fe and Zn were found to be the predominant elements along with traces of other analyzed elements. Spherical shaped ultrafine particles of <1 microm aerodynamic diameter were detected through scanning electron microscope. PM(10) particles near to the coal burning power plant produced comets indicating their potential to induce DNA damage. DNA damage property is found to be depending upon the chemical characteristics of the components associated with the particles besides the physical properties such as size and shape.

  6. Antinociceptive effects, acute toxicity and chemical composition of Vitex agnus-castus essential oil

    PubMed Central

    Khalilzadeh, Emad; Vafaei Saiah, Gholamreza; Hasannejad, Hamideh; Ghaderi, Adel; Ghaderi, Shahla; Hamidian, Gholamreza; Mahmoudi, Razzagh; Eshgi, Davoud; Zangisheh, Mahsa

    2015-01-01

    Objective: Vitex agnus-castus (VAC) and its essential oil have been traditionally used to treat many conditions and symptoms such as premenstrual problems, mastalgia, inflammation, sexual dysfunction, and pain. In this study, the effects of essential oil extracted from Vitex agnus-castus (EOVAC) leaves were investigated in three behavioral models of nociception in adult male Wistar rats. Materials and methods: Chemical composition of EOVAC was analyzed using gas chromatography – mass spectrometry (GC-MS) and also its possible toxicity was determined in mice. Analgesic effect of EOVAC was determined using tail immersion test, formalin test, and acetic acid-induced visceral pain in rats. Results: EOVAC (s.c.) and morphine (i.p.) significantly (p<0.05) reduced pain responses in both formalin and tail immersion tests. In the study of evolved mechanisms, pretreatment with naloxone or atropine significantly (p <0.05) reversed the essential oil-induced analgesia in both formalin and tail immersion tests. Moreover, EOVAC and Piroxicam produced significant (p<0.05) inhibition in the acetic acid-induced writhing response. EOVAC did not show any mortality even at high dose (5 g/kg, p.o.) of administration in toxicity test. Moreover, according to GC-MS results, major components of the EOVAC were α-pinene (14.83%), limonene (10.29%), β-caryophyllene (6.9%), sabinene (5.27%), and β-farnesene (5.9%). Conclusions: These results suggest that endogenous opioidergic system as well as muscarinergic receptors of cholinergic system may be involve in the antinociceptive activity of Vitex agnus-castus essential oil in these models of pain in rats. PMID:26101755

  7. Antifungal activity, toxicity and chemical composition of the essential oil of Coriandrum sativum L. fruits.

    PubMed

    Soares, Bruna V; Morais, Selene M; dos Santos Fontenelle, Raquel Oliveira; Queiroz, Vanessa A; Vila-Nova, Nadja S; Pereira, Christiana M C; Brito, Edy S; Neto, Manoel A S; Brito, Erika H S; Cavalcante, Carolina S P; Castelo-Branco, Débora S C M; Rocha, Marcos F G

    2012-01-01

    The aims of this study were to test the antifungal activity, toxicity and chemical composition of essential oil from C. sativum L. fruits. The essential oil, obtained by hydro-distillation, was analyzed by gas chromatography/mass spectroscopy. Linalool was the main constituent (58.22%). The oil was considered bioactive, showing an LC₅₀ value of 23 μg/mL in the Artemia salina lethality test. The antifungal activity was evaluated against Microsporum canis and Candida spp. by the agar-well diffusion method and the minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) were established by the broth microdilution method. The essential oil induced growth inhibition zones of 28 ± 5.42 and 9.25 ± 0.5 for M. canis and Candida spp. respectively. The MICs and MFCs for M. canis strains ranged from 78 to 620 and 150 to 1,250 μg/mL, and the MICs and MFCs for Candida spp strains ranged from 310 to 620 and 620 to 1,250 μg/mL, respectively. C. sativum essential oil is active in vitro against M. canis and Candida spp. demonstrating good antifungal activity.

  8. Chemical mixtures in untreated water from public-supply wells in the U.S.--occurrence, composition, and potential toxicity.

    PubMed

    Toccalino, Patricia L; Norman, Julia E; Scott, Jonathon C

    2012-08-01

    Chemical mixtures are prevalent in groundwater used for public water supply, but little is known about their potential health effects. As part of a large-scale ambient groundwater study, we evaluated chemical mixtures across multiple chemical classes, and included more chemical contaminants than in previous studies of mixtures in public-supply wells. We (1) assessed the occurrence of chemical mixtures in untreated source-water samples from public-supply wells, (2) determined the composition of the most frequently occurring mixtures, and (3) characterized the potential toxicity of mixtures using a new screening approach. The U.S. Geological Survey collected one untreated water sample from each of 383 public wells distributed across 35 states, and analyzed the samples for as many as 91 chemical contaminants. Concentrations of mixture components were compared to individual human-health benchmarks; the potential toxicity of mixtures was characterized by addition of benchmark-normalized component concentrations. Most samples (84%) contained mixtures of two or more contaminants, each at concentrations greater than one-tenth of individual benchmarks. The chemical mixtures that most frequently occurred and had the greatest potential toxicity primarily were composed of trace elements (including arsenic, strontium, or uranium), radon, or nitrate. Herbicides, disinfection by-products, and solvents were the most common organic contaminants in mixtures. The sum of benchmark-normalized concentrations was greater than 1 for 58% of samples, suggesting that there could be potential for mixtures toxicity in more than half of the public-well samples. Our findings can be used to help set priorities for groundwater monitoring and suggest future research directions for drinking-water treatment studies and for toxicity assessments of chemical mixtures in water resources.

  9. Toxic Chemical System (TCS)

    SciTech Connect

    Del Gandio, P.

    1994-09-01

    The Toxic Chemical System (TCS) will have the capacity to process chemical data, calculate chemical formulas, and format the data into the United States (US) Environmental Protection Agency (EPA) Toxic Chemical Release Inventory Reporting Form R of Section 313 of the Emergency Planning and Community Right-to-Know Act (EPCRA), hereafter be referred to as ``Form R.`` The filing of this form is required of all industries which manufacture, process or otherwise use any EPA listed chemicals in quantities in excess of their threshold planning quantities (TPQ). Facilities required to file the Form R must report the quantities of both routine and accidental releases of listed toxic chemicals on-site during the calendar year and the amount contained in waste products transferred off-site. This paper describes a specialized computer system designed for regulatory compliance.

  10. Size, source and chemical composition as determinants of toxicity attributable to ambient particulate matter

    NASA Astrophysics Data System (ADS)

    Kelly, Frank J.; Fussell, Julia C.

    2012-12-01

    Particulate matter (PM) is a complex, heterogeneous mixture that changes in time and space. It encompasses many different chemical components and physical characteristics, many of which have been cited as potential contributors to toxicity. Each component has multiple sources, and each source generates multiple components. Identifying and quantifying the influences of specific components or source-related mixtures on measures of health-related impacts, especially when particles interact with other co-pollutants, therefore represents one of the most challenging areas of environmental health research. Current knowledge does not allow precise quantification or definitive ranking of the health effects of PM emissions from different sources or of individual PM components and indeed, associations may be the result of multiple components acting on different physiological mechanisms. Some results do suggest a degree of differential toxicity, namely more consistent associations with traffic-related PM emissions, fine and ultrafine particles, specific metals and elemental carbon and a range of serious health effects, including increased morbidity and mortality from cardiovascular and respiratory conditions. A carefully targeted programme of contemporary toxicological and epidemiological research, incorporating more refined approaches (e.g. greater speciation data, more refined modelling techniques, accurate exposure assessment and better definition of individual susceptibility) and optimal collaboration amongst multidisciplinary teams, is now needed to advance our understanding of the relative toxicity of particles from various sources, especially the components and reactions products of traffic. This will facilitate targeted abatement policies, more effective pollution control measures and ultimately, a reduction in the burden of disease attributable to ambient PM pollution.

  11. Investigation of fine chalk dust particles' chemical compositions and toxicities on alveolar macrophages in vitro.

    PubMed

    Zhang, Yuexia; Yang, Zhenhua; Li, Ruijin; Geng, Hong; Dong, Chuan

    2015-02-01

    The aim of the study is to investigate chemical compositions of fine chalk dust particles (chalk PM2.5) and examine their adverse effects on alveolar macrophages (AMs) in vitro. Morphologies and element concentrations of individual chalk particles were analyzed by using the quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA). The oxidative response of AMs and the potential to generate nitric oxide (NO) by luminol-dependent chemiluminescence (CL) and nitrate reductase method were assessed 4h following the treatment of AMs with differing dosages of fine chalk particles, respectively. Oxidative stress and cytotoxicity elicited by chalk PM2.5 were also examined. The results showed that fine chalk particles were mainly composed of gypsum, calcite, dolomite and a little amount of organic adhesives. Exposure to chalk PM2.5 at 100 μg mL(-1) or 300 μg mL(-1) significantly increased intracellular catalase, malondialdehyde, and NO levels and decreased superoxide dismutase level in AMs, leading to leakage of lactate dehydrogenase (LDH) and reduction of the cell viability. Furthermore, luminol-dependent CL from respiratory burst in AMs was enhanced. It was suggested that chalk PM2.5 could make oxidative damages on AMs and result in cytotoxicity, being likely attributed to excessive reactive oxygen species or reactive nitrogen species induced by mixture of fine gypsum and calcite/dolomite particles. PMID:25278178

  12. Investigation of fine chalk dust particles' chemical compositions and toxicities on alveolar macrophages in vitro.

    PubMed

    Zhang, Yuexia; Yang, Zhenhua; Li, Ruijin; Geng, Hong; Dong, Chuan

    2015-02-01

    The aim of the study is to investigate chemical compositions of fine chalk dust particles (chalk PM2.5) and examine their adverse effects on alveolar macrophages (AMs) in vitro. Morphologies and element concentrations of individual chalk particles were analyzed by using the quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA). The oxidative response of AMs and the potential to generate nitric oxide (NO) by luminol-dependent chemiluminescence (CL) and nitrate reductase method were assessed 4h following the treatment of AMs with differing dosages of fine chalk particles, respectively. Oxidative stress and cytotoxicity elicited by chalk PM2.5 were also examined. The results showed that fine chalk particles were mainly composed of gypsum, calcite, dolomite and a little amount of organic adhesives. Exposure to chalk PM2.5 at 100 μg mL(-1) or 300 μg mL(-1) significantly increased intracellular catalase, malondialdehyde, and NO levels and decreased superoxide dismutase level in AMs, leading to leakage of lactate dehydrogenase (LDH) and reduction of the cell viability. Furthermore, luminol-dependent CL from respiratory burst in AMs was enhanced. It was suggested that chalk PM2.5 could make oxidative damages on AMs and result in cytotoxicity, being likely attributed to excessive reactive oxygen species or reactive nitrogen species induced by mixture of fine gypsum and calcite/dolomite particles.

  13. Assessing chemical toxicity of ionic liquids on Vibrio fischeri: Correlation with structure and composition.

    PubMed

    Montalbán, Mercedes G; Hidalgo, Juana M; Collado-González, Mar; Díaz Baños, F Guillermo; Víllora, Gloria

    2016-07-01

    One of the most important properties of ionic liquids is their non-volatility, making them potentially "green" alternatives to volatile organic compounds. However, they are widely soluble in water, meaning that they can be released into aquatic ecosystems and so contribute to water pollution. Nevertheless, although the toxicity of ILs has been widely assessed in the literature, the information is still scarce due to the great number of ionic liquids that have been synthesized. The present work reports the toxicity of twenty-nine imidazolium-, pyridinium- and ammonium-based ionic liquids towards the bioluminescent photobacterium Vibrio fischeri. When the effect of the type of anion, the length of the alkyl chain of the cation, the cation core and the presence of a functionalized side chain in the cation on ionic liquid toxicity were analyzed, the main influence was seen to be exercised by the alkyl chain length. A Quantitative Structure-Activity Relationships-based method was used to compare the experimental results with previously estimated values and very good agreement was obtained. A relationship between the toxicity, expressed as Log EC50, and the 1-octanol-water partition coefficient was established. PMID:27139120

  14. Relationship between chemical composition and pulmonary toxicity of source-specific ambient particulate matter

    EPA Science Inventory

    Epidemiological studies have reported incidence of cardio-pulmonary disease associated with increase in particulate matter (PM) exposure. In this study, the pulmonary toxicity potential of combustion and ambient PM were investigated using data from animal studies at the US EPA....

  15. Chemical composition and fumigant toxicity of the essential oils from 16 species of Eucalyptus against Haematobia irritans (Diptera: Muscidae) adults.

    PubMed

    Juan, Laura W; Lucia, Alejandro; Zerba, Eduardo N; Harrand, Leonel; Marco, Martin; Masuh, Hector M

    2011-06-01

    Oils extracted from various species of Eucalyptus (Eucalyptus badjensis Beuzev & Welch, Eucalyptus badjensis x Eucalyptus nitens, Eucalyptus benthamii variety dorrigoensis Maiden & Cambage, Eucalyptus botryoides Smith, Eucalyptus dalrympleana Maiden, Eucalyptus fastigata Deane & Maiden, Eucalyptus nobilis L.A.S. Johnson & K. D. Hill, Eucalyptus polybractea R. Baker, Eucalyptus radiata ssp. radiata Sieber ex Spreng, Eucalyptus resinifera Smith, Eucalyptus robertsonii Blakely, Eucalyptus rubida Deane & Maiden, Eucalyptus smithii R. Baker, Eucalyptus elata Dehnh, Eucalyptus fraxinoides Deane & Maiden, E. obliqua L'Hér) were obtained by hydrodistillation. The chemical composition of essential oils was determined by gas chromatography coupled to mass spectrometry. Essential oils were mainly composed of 1,8-cineole, alpha-pinene, alpha-terpineol, 4-terpineol, and p-cymene. Vapors from these essential oils and their major components were found to be toxic to Haematobia irritans (L.) (Diptera: Muscidae) adults. An aliquot of each oil was placed in a cylindrical test chamber, and the number of knocked down flies was recorded as a function of time. Knockdown time 50% was then calculated. Results showed that essential oil of E. polybractea had the highest knockdown activity of 3.44 min. A correlation was observed between the content of 1,8-cineole in the Eucalyptus essential oils and the corresponding toxic effect.

  16. Chemical composition and fumigant toxicity of the essential oils from 16 species of Eucalyptus against Haematobia irritans (Diptera: Muscidae) adults.

    PubMed

    Juan, Laura W; Lucia, Alejandro; Zerba, Eduardo N; Harrand, Leonel; Marco, Martin; Masuh, Hector M

    2011-06-01

    Oils extracted from various species of Eucalyptus (Eucalyptus badjensis Beuzev & Welch, Eucalyptus badjensis x Eucalyptus nitens, Eucalyptus benthamii variety dorrigoensis Maiden & Cambage, Eucalyptus botryoides Smith, Eucalyptus dalrympleana Maiden, Eucalyptus fastigata Deane & Maiden, Eucalyptus nobilis L.A.S. Johnson & K. D. Hill, Eucalyptus polybractea R. Baker, Eucalyptus radiata ssp. radiata Sieber ex Spreng, Eucalyptus resinifera Smith, Eucalyptus robertsonii Blakely, Eucalyptus rubida Deane & Maiden, Eucalyptus smithii R. Baker, Eucalyptus elata Dehnh, Eucalyptus fraxinoides Deane & Maiden, E. obliqua L'Hér) were obtained by hydrodistillation. The chemical composition of essential oils was determined by gas chromatography coupled to mass spectrometry. Essential oils were mainly composed of 1,8-cineole, alpha-pinene, alpha-terpineol, 4-terpineol, and p-cymene. Vapors from these essential oils and their major components were found to be toxic to Haematobia irritans (L.) (Diptera: Muscidae) adults. An aliquot of each oil was placed in a cylindrical test chamber, and the number of knocked down flies was recorded as a function of time. Knockdown time 50% was then calculated. Results showed that essential oil of E. polybractea had the highest knockdown activity of 3.44 min. A correlation was observed between the content of 1,8-cineole in the Eucalyptus essential oils and the corresponding toxic effect. PMID:21735933

  17. Chemical composition, toxicity and larvicidal and antifungal activities of Persea americana (avocado) seed extracts.

    PubMed

    Leite, João Jaime Giffoni; Brito, Erika Helena Salles; Cordeiro, Rossana Aguiar; Brilhante, Raimunda Sâmia Nogueira; Sidrim, José Júlio Costa; Bertini, Luciana Medeiros; Morais, Selene Maia de; Rocha, Marcos Fábio Gadelha

    2009-01-01

    The present study had the aim of testing the hexane and methanol extracts of avocado seeds, in order to determine their toxicity towards Artemia salina, evaluate their larvicidal activity towards Aedes aegypti and investigate their in vitro antifungal potential against strains of Candida spp, Cryptococcus neoformans and Malassezia pachydermatis through the microdilution technique. In toxicity tests on Artemia salina, the hexane and methanol extracts from avocado seeds showed LC50 values of 2.37 and 24.13 mg mL-1 respectively. Against Aedes aegypti larvae, the LC50 results obtained were 16.7 mg mL-1 for hexane extract and 8.87 mg mL-1 for methanol extract from avocado seeds. The extracts tested were also active against all the yeast strains tested in vitro, with differing results such that the minimum inhibitory concentration of the hexane extract ranged from 0.625 to 1.25mg L-(1), from 0.312 to 0.625 mg mL-1 and from 0.031 to 0.625 mg mL-1, for the strains of Candida spp, Cryptococcus neoformans and Malassezia pachydermatis, respectively. The minimal inhibitory concentration for the methanol extract ranged from 0.125 to 0.625 mg mL-1, from 0.08 to 0.156 mg mL-1 and from 0.312 to 0.625 mg mL-1, for the strains of Candida spp., Cryptococcus neoformans and Malassezia pachydermatis, respectively.

  18. Chemical composition, antimicrobial properties and toxicity evaluation of the essential oil of Cupressus lusitanica Mill. leaves from Cameroon

    PubMed Central

    2013-01-01

    Background The leaves of Cupressus lusitanica Mill. are used in the western highlands of Cameroon for their medicinal property. Methods The leaves of this species were collected in the West Region of Cameroon in August 2010 and subjected to hydrodistillation to obtain the essential oil. The oil was fractionated using adsorption column chromatography. The chemical composition of this oil and its fractions was analysed by gas chromatography–mass spectrometry (GC-MS). The essential oil and fractions were tested for antimicrobial activity against eight bacterial species and six species of Candida by the agar diffusion method. Macrodilution method was used to determine the minimum inhibition concentrations (MICs) and minimum bactericidal and/or fungicidal concentrations (MBCs and MFCs). The toxicity profile of the oil was studied using Swiss mice and Wistar albino rats. Results Forty-nine compounds were identified in the essential oil. The main components were germacrene D (18.5%), epi-zonarene (8.2%), cis-calamenene (8.2%), terpinen-4-ol (6.3%), linalool (6.0%) and umbellulone (6.0%). Enterococcus faecalis, Proteus mirabilis and Candida albicans were most susceptible to the oil (MICs of 1.25 and 0.16% for bacteria and fungi respectively). The estimated oral LD50 was 6.33 g/kg. There was an increase in sera ALT and AST activities while the blood cells and protein levels decreased in treated animals. Conclusion The results obtained from this study support the ethnomedicinal use of C. lusitanica leaf oil in the treatment of whooping cough and skin infections though it should be used with care. This plant oil could be useful in the standardisation of phytomedicine. PMID:23758765

  19. Release and toxicity of dental resin composite

    PubMed Central

    Gupta, Saurabh K.; Saxena, Payal; Pant, Vandana A.; Pant, Aditya B.

    2012-01-01

    Dental resin composite that are tooth-colored materials have been considered as possible substitutes to mercury-containing silver amalgam filling. Despite the fact that dental resin composites have improved their physico-chemical properties, the concern for its intrinsic toxicity remains high. Some components of restorative composite resins are released in the oral environment initially during polymerization reaction and later due to degradation of the material. In vitro and in vivo studies have clearly identified that these components of restorative composite resins are toxic. But there is a large gap between the results published by research laboratories and clinical reports. The objective of this manuscript was to review the literature on release phenomenon as well as in vitro and in vivo toxicity of dental resin composite. Interpretation made from the recent data was also outlined. PMID:23293458

  20. Release and toxicity of dental resin composite.

    PubMed

    Gupta, Saurabh K; Saxena, Payal; Pant, Vandana A; Pant, Aditya B

    2012-09-01

    Dental resin composite that are tooth-colored materials have been considered as possible substitutes to mercury-containing silver amalgam filling. Despite the fact that dental resin composites have improved their physico-chemical properties, the concern for its intrinsic toxicity remains high. Some components of restorative composite resins are released in the oral environment initially during polymerization reaction and later due to degradation of the material. In vitro and in vivo studies have clearly identified that these components of restorative composite resins are toxic. But there is a large gap between the results published by research laboratories and clinical reports. The objective of this manuscript was to review the literature on release phenomenon as well as in vitro and in vivo toxicity of dental resin composite. Interpretation made from the recent data was also outlined.

  1. Toxic chemical considerations for tank farm releases

    SciTech Connect

    Van Keuren, J.C.; Davis, J.S., Westinghouse Hanford

    1996-08-01

    This topical report contains technical information used to determine the accident consequences of releases of toxic chemical and gases for the Tank Farm Final Safety Analysis report (FSAR).It does not provide results for specific accident scenarios but does provide information for use in those calculations including chemicals to be considered, chemical concentrations, chemical limits and a method of summing the fractional contributions of each chemical. Tank farm composites evaluated were liquids and solids for double shell tanks, single shell tanks, all solids,all liquids, headspace gases, and 241-C-106 solids. Emergency response planning guidelines (ERPGs) were used as the limits.Where ERPGs were not available for the chemicals of interest, surrogate ERPGs were developed. Revision 2 includes updated sample data, an executive summary, and some editorial revisions.

  2. Computing Equilibrium Chemical Compositions

    NASA Technical Reports Server (NTRS)

    Mcbride, Bonnie J.; Gordon, Sanford

    1995-01-01

    Chemical Equilibrium With Transport Properties, 1993 (CET93) computer program provides data on chemical-equilibrium compositions. Aids calculation of thermodynamic properties of chemical systems. Information essential in design and analysis of such equipment as compressors, turbines, nozzles, engines, shock tubes, heat exchangers, and chemical-processing equipment. CET93/PC is version of CET93 specifically designed to run within 640K memory limit of MS-DOS operating system. CET93/PC written in FORTRAN.

  3. Chemical toxicity of red cells.

    PubMed Central

    Piomelli, S

    1981-01-01

    Exposure to toxic chemicals may result in alterations of red cell function. In certain cases, the toxic effect requires a genetic predisposition and thus affects only a restricted number of individuals; in other instances, the toxic effect is exerted on the hematopoietic system of every person. Glucose-6-phosphate dehydrogenase deficiency is probably the most widespread genetic disorder. It is observed at highest frequency in populations from subtropical countries as a result of its selective advantage vis à vis falciparum malaria. The gene controlling this enzyme is located on the X-chromosome; thus, the defect is sex-linked. Individuals with a genetic defect of this enzyme are extremely susceptible to hemolysis, when exposed to oxidant drugs (such as certain antimalarials and sulfonamides) because of the inability of their red cells to regenerate NADPH. Lead poisoning result in profound effects on the process of heme synthesis. Among the steps most sensitive to lead toxicity are the enzyme delta-aminolevulinic acid dehydratase and the intramitochondrial step that leads to the incorporation of iron into protoporphyrin. By these mechanisms, in severe lead intoxication there is an accumulation of large amounts of delta-aminolevulinic acid (a compound with inherent neurotoxicity), and there are abnormalities of mitochondrial function in all cells of the body. Individuals living in an industrialized society are unavoidably exposed to some environmental lead. Recent evidence indicates that, even at levels of exposure which do not increase the blood lead level above values presently considered normal, abnormalities of heme synthesis are clearly detectable. PMID:7016524

  4. Chemical composition, toxicity and non-target effects of Pinus kesiya essential oil: An eco-friendly and novel larvicide against malaria, dengue and lymphatic filariasis mosquito vectors.

    PubMed

    Govindarajan, Marimuthu; Rajeswary, Mohan; Benelli, Giovanni

    2016-07-01

    Mosquitoes (Diptera: Culicidae) are vectors of important parasites and pathogens causing death, poverty and social disability worldwide, with special reference to tropical and subtropical countries. The overuse of synthetic insecticides to control mosquito vectors lead to resistance, adverse environmental effects and high operational costs. Therefore, the development of eco-friendly control tools is an important public health challenge. In this study, the mosquito larvicidal activity of Pinus kesiya leaf essential oil (EO) was evaluated against the malaria vector Anopheles stephensi, the dengue vector Aedes aegypti and the lymphatic filariasis vector Culex quinquefasciatus. The chemical composition of the EO was analyzed by gas chromatography-mass spectroscopy. GC-MS revealed that the P. kesiya EO contained 18 compounds. Major constituents were α-pinene, β-pinene, myrcene and germacrene D. In acute toxicity assays, the EO showed significant toxicity against early third-stage larvae of An. stephensi, Ae. aegypti and Cx. quinquefasciatus, with LC50 values of 52, 57, and 62µg/ml, respectively. Notably, the EO was safer towards several aquatic non-target organisms Anisops bouvieri, Diplonychus indicus and Gambusia affinis, with LC50 values ranging from 4135 to 8390µg/ml. Overall, this research adds basic knowledge to develop newer and safer natural larvicides from Pinaceae plants against malaria, dengue and filariasis mosquito vectors. PMID:26995063

  5. Chemical composition, toxicity and non-target effects of Pinus kesiya essential oil: An eco-friendly and novel larvicide against malaria, dengue and lymphatic filariasis mosquito vectors.

    PubMed

    Govindarajan, Marimuthu; Rajeswary, Mohan; Benelli, Giovanni

    2016-07-01

    Mosquitoes (Diptera: Culicidae) are vectors of important parasites and pathogens causing death, poverty and social disability worldwide, with special reference to tropical and subtropical countries. The overuse of synthetic insecticides to control mosquito vectors lead to resistance, adverse environmental effects and high operational costs. Therefore, the development of eco-friendly control tools is an important public health challenge. In this study, the mosquito larvicidal activity of Pinus kesiya leaf essential oil (EO) was evaluated against the malaria vector Anopheles stephensi, the dengue vector Aedes aegypti and the lymphatic filariasis vector Culex quinquefasciatus. The chemical composition of the EO was analyzed by gas chromatography-mass spectroscopy. GC-MS revealed that the P. kesiya EO contained 18 compounds. Major constituents were α-pinene, β-pinene, myrcene and germacrene D. In acute toxicity assays, the EO showed significant toxicity against early third-stage larvae of An. stephensi, Ae. aegypti and Cx. quinquefasciatus, with LC50 values of 52, 57, and 62µg/ml, respectively. Notably, the EO was safer towards several aquatic non-target organisms Anisops bouvieri, Diplonychus indicus and Gambusia affinis, with LC50 values ranging from 4135 to 8390µg/ml. Overall, this research adds basic knowledge to develop newer and safer natural larvicides from Pinaceae plants against malaria, dengue and filariasis mosquito vectors.

  6. Chemical recycling of scrap composites

    NASA Technical Reports Server (NTRS)

    Allred, Ronald E.; Salas, Richard M.

    1994-01-01

    There are no well-developed technologies for recycling composite materials other than grinding to produce fillers. New approaches are needed to reclaim these valuable resources. Chemical or tertiary recycling, conversion of polymers into low molecular weight hydrocarbons for reuse as chemicals or fuels, is emerging as the most practical means for obtaining value from waste plastics and composites. Adherent Technologies is exploring a low-temperature catalytic process for recycling plastics and composites. Laboratory results show that all types of plastics, thermosets as well as thermoplastics, can be converted in high yields to valuable hydrocarbon products. This novel catalytic process runs at 200 C, conversion times are rapid, the process is closed and, thus, nonpolluting, and no highly toxic gas or liquid products have been observed so no negative environmental impact will result from its implementation. Tests on reclamation of composite materials show that epoxy, imide, and engineering thermoplastic matrices can be converted to low molecular weight hydrocarbons leaving behind the reinforcing fibers for reuse as composite reinforcements in secondary, lower-performance applications. Chemical recycling is also a means to dispose of sensitive or classified organic materials without incineration and provides a means to eliminate or reduce mixed hazardous wastes containing organic materials.

  7. America's Poisoned Playgrounds: Children and Toxic Chemicals.

    ERIC Educational Resources Information Center

    Freedberg, Louis

    Next to chemical and farm workers, today's children are at the greatest risk from toxic chemicals. Through their normal play activities, children are exposed to a frightening array of toxic hazards, including lead, pesticides, arsenic, and unknown dangers from abandoned landfills and warehouses. Through a series of documented examples, the author…

  8. Chemical composition, acute toxicity, and antinociceptive activity of the essential oil of a plant breeding cultivar of basil (Ocimum basilicum L.).

    PubMed

    Venâncio, Antônio Medeiros; Onofre, Alexandre Sherlley; Lira, Amintas Figueiredo; Alves, Péricles Barreto; Blank, Arie Fitzgerald; Antoniolli, Angelo Roberto; Marchioro, Murilo; Estevam, Charles dos Santos; de Araujo, Brancilene Santos

    2011-05-01

    Ocimum basilicum L. is an aromatic herb used in Brazil to treat illnesses such as respiratory and rheumatic problems, vomiting, and pain. In the present study, the chemical composition, acute toxicity, and antinociceptive effects of the essential oil (EO) of the cultivar "Maria Bonita" obtained from O. basilicum L. PI 197442 genotype were evaluated in Swiss mice (20-35 g each). Lethal dose to cause 50 % death (LD50) was calculated from a dose-response curve (100-5000 mg/kg body wt.; n = 6) as 532 mg/kg body wt. In the acetic acid-induced writhing test (0.6 % i. p.), EO (50, 100, and 200 mg/kg body wt., n = 8, s. c.) was effective in reducing the abdominal contractions at all doses (48-78 %). In the hot-plate test, EO significantly increased the latency at 50 mg/kg body wt. at all times (37-52 %, n = 8, s. c.). However, the effects of morphine and EO at 50 mg/kg were reverted in the presence of naloxone, an opioid antagonist. In the formalin test, EO significantly reduced paw licking time in the first and second phases of pain at 200 mg/kg body wt. (38 and 75 %, respectively, n = 8, s. c.). The results suggested that the peripheral and central antinociceptive effects of EO are related to the inhibition of the biosynthesis of pain mediators, such as prostaglandins and prostacyclins, and its ability to interact with opioid receptors.

  9. Identification of Chemical Toxicity Using Ontology Information of Chemicals.

    PubMed

    Jiang, Zhanpeng; Xu, Rui; Dong, Changchun

    2015-01-01

    With the advance of the combinatorial chemistry, a large number of synthetic compounds have surged. However, we have limited knowledge about them. On the other hand, the speed of designing new drugs is very slow. One of the key causes is the unacceptable toxicities of chemicals. If one can correctly identify the toxicity of chemicals, the unsuitable chemicals can be discarded in early stage, thereby accelerating the study of new drugs and reducing the R&D costs. In this study, a new prediction method was built for identification of chemical toxicities, which was based on ontology information of chemicals. By comparing to a previous method, our method is quite effective. We hope that the proposed method may give new insights to study chemical toxicity and other attributes of chemicals.

  10. Toxicity testing in chemical safety evaluation.

    PubMed

    Bus, James S

    2007-02-01

    The modern era of chemistry has resulted in dramatic improvements in the overall human condition. In addition to new pharmaceuticals, modern chemistry has brought with it enormous health and social benefits Introduction of chemistry-based technologies, however, has also been clearly associated with potential human health risks. The dramatic increase in pharmaceutical and chemical technologies in the post World War II era, coupled with associated examples of demonstrated human toxicity, led to development and application of an expanded and standardized battery of animal and other toxicity tests designed to characterize the potential hazards and risks associated with chemical exposures. This unit discusses the current approach to industrial chemical and pesticide toxicity testing.

  11. Ranking chemicals based on chronic toxicity data.

    PubMed

    De Rosa, C T; Stara, J F; Durkin, P R

    1985-12-01

    During the past 3 years, EPA's ECAO/Cincinnati has developed a method to rank chemicals based on chronic toxicity data. This ranking system reflects two primary attributes of every chemical: the minimum effective dose and the type of effect elicited at that dose. The purpose for developing this chronic toxicity ranking system was to provide the EPA with the technical background required to adjust the RQs of hazardous substances designated in Section 101(14) of CERCLA or "Superfund." This approach may have applications to other areas of interest to the EPA and other regulatory agencies where ranking of chemicals based on chronic toxicity is desired. PMID:3843499

  12. Chemical composition of Mars

    NASA Technical Reports Server (NTRS)

    Morgan, J. W.; Anders, E.

    1979-01-01

    The chemical composition of Mars is estimated from the cosmochemical model of Ganapathy and Anders (1974) with additional petrological and geophysical constraints. The model assumes that planets and chondrites underwent the same fractionation processes in the solar nebula, and constraints are imposed by the abundance of the heat-producing elements, U, Th and K, the volatile-rich component and the high density of the mantle. Global abundances of 83 elements are presented, and it is noted that the mantle is an iron-rich garnet wehrlite, nearly identical to the bulk moon composition of Morgan at al. (1978) and that the core is sulfur poor (3.5% S). The comparison of model compositions for the earth, Venus, Mars, the moon and a eucrite parent body suggests that volatile depletion correlates mainly with size rather than with radial distance from the sun.

  13. Toxic Chemicals Use in School Labs Examined.

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1982

    1982-01-01

    The Consumer Product Safety Commission will recommend an information network to inform students and teachers of current toxicity evaluations of chemicals and of possible use of less hazardous substitutes. Lists names of 33 suspected carcinogens and 11 suspected teratogens. (SK)

  14. Differential Toxicity Characterization of Green Alternative Chemicals

    EPA Science Inventory

    Assessing the toxicity of a chemical across all possible disease domains and understanding its dose- response behavior cost millions to tens of millions of dollars per chemical, and can take years to decades to evaluate fully. This expense and the lack of regulatory requirements ...

  15. [Arsine: an unknown industrial chemical toxic].

    PubMed

    Plantamura, J; Dorandeu, F; Burnat, P; Renard, C

    2011-07-01

    Arsines family includes many compounds with various toxicities. Arsenic trihydride or arsine is the most toxic form of arsenic. Powerful haemolytic gas, it has never been used as a chemical weapon because its toxicity is not immediate and it is non persistent. However, cases of industrial poisoning with arsine are still identified in spite of a strict regulation at work. It is also identified as a potential toxic of chemical terrorism. This agent, of which the mechanism of action is still not well defined, is badly recognized because of intoxications rarity. However, fast detection means are available. Health professionals and especially those who are involved in piratox plan need to learn to recognize arsine intoxication (hematuria, oliguria, haemolytic anemia) in order to provide early, specific treatment and avoid damages.

  16. [Arsine: an unknown industrial chemical toxic].

    PubMed

    Plantamura, J; Dorandeu, F; Burnat, P; Renard, C

    2011-07-01

    Arsines family includes many compounds with various toxicities. Arsenic trihydride or arsine is the most toxic form of arsenic. Powerful haemolytic gas, it has never been used as a chemical weapon because its toxicity is not immediate and it is non persistent. However, cases of industrial poisoning with arsine are still identified in spite of a strict regulation at work. It is also identified as a potential toxic of chemical terrorism. This agent, of which the mechanism of action is still not well defined, is badly recognized because of intoxications rarity. However, fast detection means are available. Health professionals and especially those who are involved in piratox plan need to learn to recognize arsine intoxication (hematuria, oliguria, haemolytic anemia) in order to provide early, specific treatment and avoid damages. PMID:21840437

  17. Management of chemical toxic wastes

    SciTech Connect

    Gold, L.

    1982-05-25

    Two regimes of vertical shaft furnace operation can be employed to slag encapsulate hazardous chemical wastes. One of these is similar to a method applicable to radioactive wastes, involving the pouring of hot molten slag from a coal reactor over the hazardous matter contained in a suitable designed crucible. The other method is especially appropriate for the treatment of chemical wastes that have become mixed with a great deal of soil or other diluent as must be handled as in the case of the love canal incident. It consists of feeding the contaminated solid mass into the coal reactor with a predetermined amount of coal and limestone that will still admit an adequate heat balance to generate a carefully tailored slag to incorporate the reacted waste feedstock.

  18. DOE contractor's meeting on chemical toxicity

    SciTech Connect

    Not Available

    1987-01-01

    The Office of Health and Environmental Research (OHER) is required to determine the potential health and environmental effects associated with energy production and use. To ensure appropriate communication among investigators and scientific disciplines that these research studies represent, OHER has sponsored workshops. This document provides a compilation of activities at the Third Annual DOE/OHER Workshop. This year's workshop was broadened to include all OHER activities identified as within the chemical effects area. The workshop consisted of eight sessions entitled Isolation and Detection of Toxic chemicals; Adduct Formation and Repair; Chemical Toxicity (Posters); Metabolism and Genotoxicity; Inhalation Toxicology; Gene Regulation; Metals Toxicity; and Biological Mechanisms. This document contains abstracts of the information presented by session.

  19. The molecular basis of chemical toxicity.

    PubMed Central

    McKinney, J D

    1985-01-01

    Studies of structure-activity relationships and molecular mechanisms of action are fundamental to our understanding of the harmful effects of chemicals on the environment and their more direct effects on human health. It is important to identify factors that determine toxicological effects of foreign chemicals in biological systems and to assess our knowledge about chemical mechanisms of toxicity. Several fundamental mechanisms underlying toxic action are described, and the importance of studying receptor-substrate interactions is stressed. The Ah receptor is cited as an example of a protein-small molecule interaction associated with extreme acute toxicity in laboratory animals. It is recognized that reliable attempts at predictive toxicology across compound classes through structural and theoretical chemistry approaches must be based on sound knowledge about mechanisms of action at the molecular level. Such studies also contribute to the knowledge base in biomedical and physical sciences. PMID:2998750

  20. RELATIONSHIP BETWEEN COMPOSITION AND TOXICITY OF ENGINE EMISSION SAMPLES

    SciTech Connect

    Mauderly, J; Seagrave, J; McDonald; J Eide,I Zielinska, B Lawson, D

    2003-08-24

    Differences in the lung toxicity and bacterial mutagenicity of seven samples from gasoline and diesel vehicle emissions were reported previously [1]. Filter and vapor-phase semivolatile organic samples were collected from normal and high-emitter gasoline and diesel vehicles operated on chassis dynamometers on the Unified Driving Cycle, and the compositions of the samples were measured in detail. The two fractions of each sample were combined in their original mass collection ratios, and the toxicity of the seven samples was compared by measuring inflammation and tissue damage in rat lungs and mutagenicity in bacteria. There was good agreement among the toxicity response variables in ranking the samples and demonstrating a five-fold range of toxicity. The relationship between chemical composition and toxicity was analyzed by a combination of principal component analysis (PCA) and partial least squares regression (PLS, also known as projection to latent surfaces). The PCA /PLS analysis revealed the chemical constituents co-varying most strongly with toxicity and produced models predicting the relative toxicity of the samples with good accuracy. The results demonstrated the utility of the PCA/PLS approach, which is now being applied to additional samples, and it also provided a starting point for confirming the compounds that actually cause the effects.

  1. Comparative toxicity of chemicals to earthworms

    SciTech Connect

    Callahan, C.A.; Shirazi, M.A. ); Neuhauser, E.F. )

    1994-02-01

    The concentration-response (mortality) relationships of four species of earthworms, Eisenia fetida (Savigny), Allolobophora tuberculata (Eisen), Eudrilus eugeniae (Kinberg), and Perionyx excavatus (Perrier) are summarized for 62 chemicals and two test protocols. A Weibull function is used to summarize these data for each chemical in terms of sensitivity and toxicity, in addition to the LC50. The estimation of the Weibull parameters a and k summarize the entire concentration-response relationship. This technique should be applicable to a variety of testing protocols with different species whenever the goal is summarizing the shape of the concentration-response curves to fully evaluate chemical impact on organisms. In some cases for these data four orders of magnitude separate LC50s of the soil test and the contact test for the same chemical and species. All four species appear to be similar in range of toxicity and tolerance to these chemicals, suggesting that Eisenia fetida and may be representative of these four species and these chemicals.

  2. Chemical Compositions of Stars

    NASA Astrophysics Data System (ADS)

    Leckrone, D.; Murdin, P.

    2000-11-01

    In 1835, in a famously inaccurate forecast, the French philosopher Auguste Comte wrote of stars that, `We understand the possibility of determining their shapes, their distances, their sizes and their movements; whereas we would never know how to study by any means their chemical composition…'. At the close of the 20th century the accurate measurement of the abundances of the chemical elements in...

  3. Chemical composition of Borislav ozocerite

    SciTech Connect

    Batukova, G.I.; Davydov, V.D.; Shcherbik, L.K.; Petrishchev, K.P.; Kolodko, N.P.; Moiseyeva, A.F.

    1983-01-01

    Ozocerite is a natural wax product with wide commercial use. The absence of comprehensive data concerning the chemical composition and structure of ozocerite hinders the production of wax melts with predetermined properties. Slight changes in the chemical composition of wax products, difficult to detect by modern methods of investigation, have a decisive effect on the properties of these products. Individual compounds have not, so far, been identified by present-day physicochemical methods. This paper describes an investigation of the chemical composition of Borislav ozocerite using a method developed to study the composition of Soviet lignite wax. Borislav ozocerite obtained by extraction with BR-70 light petroleum spirit under industrial conditions and with BR-1 light petroleum spirit, under laboratory conditions (samples A and B, respectively) were examined. Physical and chemical properties of Borislav ozocerite were determined. 6 references, 2 figures, 3 tables.

  4. Profiling the reproductive toxicity of chemicals from multigeneration studies in the toxicity reference database

    EPA Science Inventory

    Multigeneration reproduction studies are used to characterize parental and offspring systemic toxicity, as well as reproductive toxicity of pesticides, industrial chemicals and pharmaceuticals. Results from 329 multigeneration studies on 316 chemicals have been digitized into sta...

  5. Method of forming a chemical composition

    DOEpatents

    Bingham, Dennis N.; Wilding, Bruce M.; Klingler, Kerry M.; Zollinger, William T.; Wendt, Kraig M.

    2007-10-09

    A method of forming a chemical composition such as a chemical hydride is described and which includes the steps of selecting a composition having chemical bonds and which is capable of forming a chemical hydride; providing a source of hydrogen; and exposing the selected composition to an amount of ionizing radiation to encourage the changing of the chemical bonds of the selected composition, and chemically reacting the selected composition with the source of hydrogen to facilitate the formation of a chemical hydride.

  6. Toxicity test of a dental commercial composite

    PubMed Central

    Ponce-Bravo, Santa; Martínez-Rivera, José-Luis; Garcés-Ortíz, Maricela

    2015-01-01

    Background International rules must be followed for testing biosecurity in dental materials. A new brand of restorative material appeared in the market and regulations indicated that it should be tested for toxicity. Objectives The aim of this study was to determine the 90-day sub chronic toxicity of one triethylene glycol dimethacrylate containing composite (MEDENTAL Light-Cure Composite™) orally administered to rats according to Organization for Economic Co-Operation and Development no. 48 guidelines and the requirements specified in the ISO 10993-11. Material and Methods Wistar rats ate the polymerized composite during 90 days and were observed to determine changes in their behavior, eye and skin signs and other attitudes such as aggressiveness, posture, walking and response to handling. After 90 days were sacrificed to ascertain blood alterations, we did special hematological tests and assessed microscopic slides from 33 different organs. Results We recorded no significant changes in clinical behavior of the animals. Microscopic review of the H&E stained slides obtained from the analyzed organs showed no abnormal inflammatory or cytological changes and all hematological special tests were within normal limits. Conclusions Results of this study show that under our experimental conditions the MEDENTAL Light-Cure Composite™ does not produce inflammatory or cytological changes suggestive of toxicity. Key words:Dental materials, composite resin, toxicity, inflammation, TEGDMA. PMID:26155348

  7. Chemical composition of Mars

    USGS Publications Warehouse

    Morgan, J.W.; Anders, E.

    1979-01-01

    The composition of Mars has been calculated from the cosmochemical model of Ganapathy and Anders (1974) which assumes that planets and chondrites underwent the same 4 fractionation processes in the solar nebula. Because elements of similar volatility stay together in these processes, only 4 index elements (U, Fe, K and Tl or Ar36) are needed to calculate the abundances of all 83 elements in the planet. The values chosen are U = 28 ppb, K = 62 ppm (based on K U = 2200 from orbital ??-spectrometry and on thermal history calculations by Tokso??z and Hsui (1978) Fe = 26.72% (from geophysical data), and Tl = 0.14 ppb (from the Ar36 and Ar40 abundances measured by Viking). The mantle of Mars is an iron-rich [Mg/(Mg + Fe) = 0.77] garnet wehrlite (?? = 3.52-3.54 g/cm3), similar to McGetchin and Smyth's (1978) estimate but containing more Ca and Al. It is nearly identical to the bulk Moon composition of Morgan et al. (1978b). The core makes up 0.19 of the planet and contains 3.5% S-much less than estimated by other models. Volatiles have nearly Moon-like abundances, being depleted relative to the Earth by factors of 0.36 (K-group, Tcond = 600-1300 K) or 0.029 (Tl group, Tcond < 600 K). The water abundance corresponds to a 9 m layer, but could be higher by as much as a factor of 11. Comparison of model compositions for 5 differentiated planets (Earth, Venus, Mars, Moon, and eucrite parent body) suggests that volatile depletion correlates mainly with size rather than with radial distance from the Sun. However, the relatively high volatile content of shergottites and some chondrites shows that the correlation is not simple; other factors must also be involved. ?? 1979.

  8. Chemical composition, antifeedant, repellent, and toxicity activities of the rhizomes of galangal, Alpinia galanga against Asian subterranean termites, Coptotermes gestroi and Coptotermes curvignathus (Isoptera: Rhinotermitidae).

    PubMed

    Abdullah, Fauziah; Subramanian, Partiban; Ibrahim, Halijah; Abdul Malek, Sri Nurestri; Lee, Guan Serm; Hong, Sok Lai

    2015-01-01

    Dual choice bioassays were used to evaluate the antifeedant property of essential oil and methanolic extract of Alpinia galanga (L.) (locally known as lengkuas) against two species of termites, Coptotermes gestroi (Wasmann) and Coptotermes curvignathus (Holmgren) (Isoptera: Rhinotermitidae). A 4-cm-diameter paper disc treated with A. galanga essential oil and another treated with either methanol or hexane as control were placed in a petri dish with 10 termites. Mean consumption of paper discs (miligram) treated with 2,000 ppm of essential oil by C. gestroi was 3.30 ± 0.24 mg and by C. curvignathus was 3.32 ± 0.24 mg. A. galanga essential oil showed significant difference in antifeedant effect, 2,000 ppm of A. galanga essential oil was considered to be the optimum concentration that gave maximum antifeedant effect. The essential oil composition was determined using gas chromatography-mass spectrometry. The major component of the essential oil was 1,8-cineol (61.9%). Antifeedant bioassay using 500 ppm of 1,8-cineol showed significant reduction in paper consumption by both termite species. Thus, the bioactive agent in A. galangal essential oil causing antifeeding activity was identified as 1,8-cineol. Repellent activity shows that 250 ppm of 1,8-cineol caused 50.00 ± 4.47% repellency for C. gestroi, whereas for C. curvignathus 750 ppm of 1,8-cineol was needed to cause similar repellent activity (56.67 ± 3.33%). C. curvignathus is more susceptible compare to C. gestroi in Contact Toxicity study, the lethal dose (LD50) of C. curvignathus was 945 mg/kg, whereas LD50 value for C. gestroi was 1,102 mg/kg. Hence 1,8-cineol may be developed as an alternative control against termite in sustainable agriculture practices. PMID:25688085

  9. Chemical composition, antifeedant, repellent, and toxicity activities of the rhizomes of galangal, Alpinia galanga against Asian subterranean termites, Coptotermes gestroi and Coptotermes curvignathus (Isoptera: Rhinotermitidae).

    PubMed

    Abdullah, Fauziah; Subramanian, Partiban; Ibrahim, Halijah; Abdul Malek, Sri Nurestri; Lee, Guan Serm; Hong, Sok Lai

    2015-01-01

    Dual choice bioassays were used to evaluate the antifeedant property of essential oil and methanolic extract of Alpinia galanga (L.) (locally known as lengkuas) against two species of termites, Coptotermes gestroi (Wasmann) and Coptotermes curvignathus (Holmgren) (Isoptera: Rhinotermitidae). A 4-cm-diameter paper disc treated with A. galanga essential oil and another treated with either methanol or hexane as control were placed in a petri dish with 10 termites. Mean consumption of paper discs (miligram) treated with 2,000 ppm of essential oil by C. gestroi was 3.30 ± 0.24 mg and by C. curvignathus was 3.32 ± 0.24 mg. A. galanga essential oil showed significant difference in antifeedant effect, 2,000 ppm of A. galanga essential oil was considered to be the optimum concentration that gave maximum antifeedant effect. The essential oil composition was determined using gas chromatography-mass spectrometry. The major component of the essential oil was 1,8-cineol (61.9%). Antifeedant bioassay using 500 ppm of 1,8-cineol showed significant reduction in paper consumption by both termite species. Thus, the bioactive agent in A. galangal essential oil causing antifeeding activity was identified as 1,8-cineol. Repellent activity shows that 250 ppm of 1,8-cineol caused 50.00 ± 4.47% repellency for C. gestroi, whereas for C. curvignathus 750 ppm of 1,8-cineol was needed to cause similar repellent activity (56.67 ± 3.33%). C. curvignathus is more susceptible compare to C. gestroi in Contact Toxicity study, the lethal dose (LD50) of C. curvignathus was 945 mg/kg, whereas LD50 value for C. gestroi was 1,102 mg/kg. Hence 1,8-cineol may be developed as an alternative control against termite in sustainable agriculture practices.

  10. Chemical Composition, Antifeedant, Repellent, and Toxicity Activities of the Rhizomes of Galangal, Alpinia galanga Against Asian Subterranean Termites, Coptotermes gestroi and Coptotermes curvignathus (Isoptera: Rhinotermitidae)

    PubMed Central

    Abdullah, Fauziah; Subramanian, Partiban; Ibrahim, Halijah; Abdul Malek, Sri Nurestri; Lee, Guan Serm; Hong, Sok Lai

    2015-01-01

    Dual choice bioassays were used to evaluate the antifeedant property of essential oil and methanolic extract of Alpinia galanga (L.) (locally known as lengkuas) against two species of termites, Coptotermes gestroi (Wasmann) and Coptotermes curvignathus (Holmgren) (Isoptera: Rhinotermitidae). A 4-cm-diameter paper disc treated with A. galanga essential oil and another treated with either methanol or hexane as control were placed in a petri dish with 10 termites. Mean consumption of paper discs (miligram) treated with 2,000 ppm of essential oil by C. gestroi was 3.30 ± 0.24 mg and by C. curvignathus was 3.32 ± 0.24 mg. A. galanga essential oil showed significant difference in antifeedant effect, 2,000 ppm of A. galanga essential oil was considered to be the optimum concentration that gave maximum antifeedant effect. The essential oil composition was determined using gas chromatography-mass spectrometry. The major component of the essential oil was 1,8-cineol (61.9%). Antifeedant bioassay using 500 ppm of 1,8-cineol showed significant reduction in paper consumption by both termite species. Thus, the bioactive agent in A. galangal essential oil causing antifeeding activity was identified as 1,8-cineol. Repellent activity shows that 250 ppm of 1,8-cineol caused 50.00 ± 4.47% repellency for C. gestroi, whereas for C. curvignathus 750 ppm of 1,8-cineol was needed to cause similar repellent activity (56.67 ± 3.33%). C. curvignathus is more susceptible compare to C. gestroi in Contact Toxicity study, the lethal dose (LD50) of C. curvignathus was 945 mg/kg, whereas LD50 value for C. gestroi was 1,102 mg/kg. Hence 1,8-cineol may be developed as an alternative control against termite in sustainable agriculture practices. PMID:25688085

  11. Chemical air pollutants and otorhinolaryngeal toxicity

    SciTech Connect

    Bisesi, M.S.; Rubin, A.M. . Occupational Health and Otolaryngology)

    1994-03-01

    Air pollution and the specific issue regarding the impact of airborne chemical agents to human health are familiar topics to most members of the environmental health science and environmental medicine communities. Some aspects, however, have received relatively less attention. Much has been published regarding the impact of air pollutants on the human upper and lower respiratory system, including interaction with the rhinologic (nasal) system. Relatively fewer data have been published, however, regarding the potential impact of air pollutants in reference specifically to the otologic (auditory and vestibular) and the laryngeal (larynx) system. Adverse impact to the ears, nose and throat, referred to as the otorhinolaryngeal system'', warrants attention as an important environmental health issue. Toxic interactions from exposure to many chemical air pollutants not only causes potential respiratory irritation and lung disease, but can also result in impaired hearing, balance, sense of smell, taste, and speech due to interaction with related target systems. This may be significant to environmental health risk assessment of chemical air pollutants if multi-target site models are considered.

  12. Integrated Proteomic Approaches for Understanding Toxicity of Environmental Chemicals

    EPA Science Inventory

    To apply quantitative proteomic analysis to the evaluation of toxicity of environmental chemicals, we have developed an integrated proteomic technology platform. This platform has been applied to the analysis of the toxic effects and pathways of many important environmental chemi...

  13. The Chemical Composition of Honey

    ERIC Educational Resources Information Center

    Ball, David W.

    2007-01-01

    Honey is a supersaturated sugar solution, created by bees, and used by human beings as a sweetener. However, honey is more than just a supersaturated sugar solution; it also contains acids, minerals, vitamins, and amino acids in varying quantities. In this article, we will briefly explore the chemical composition of honey. (Contains 2 figures and…

  14. Optical detection of chemical warfare agents and toxic industrial chemicals

    NASA Astrophysics Data System (ADS)

    Webber, Michael E.; Pushkarsky, Michael B.; Patel, C. Kumar N.

    2004-12-01

    We present an analytical model evaluating the suitability of optical absorption based spectroscopic techniques for detection of chemical warfare agents (CWAs) and toxic industrial chemicals (TICs) in ambient air. The sensor performance is modeled by simulating absorption spectra of a sample containing both the target and multitude of interfering species as well as an appropriate stochastic noise and determining the target concentrations from the simulated spectra via a least square fit (LSF) algorithm. The distribution of the LSF target concentrations determines the sensor sensitivity, probability of false positives (PFP) and probability of false negatives (PFN). The model was applied to CO2 laser based photoacosutic (L-PAS) CWA sensor and predicted single digit ppb sensitivity with very low PFP rates in the presence of significant amount of interferences. This approach will be useful for assessing sensor performance by developers and users alike; it also provides methodology for inter-comparison of different sensing technologies.

  15. Chemical compositions, methods of making the chemical compositions, and structures made from the chemical compositions

    DOEpatents

    Yang, Lei; Cheng, Zhe; Liu, Ze; Liu, Meilin

    2015-01-13

    Embodiments of the present disclosure include chemical compositions, structures, anodes, cathodes, electrolytes for solid oxide fuel cells, solid oxide fuel cells, fuel cells, fuel cell membranes, separation membranes, catalytic membranes, sensors, coatings for electrolytes, electrodes, membranes, and catalysts, and the like, are disclosed.

  16. Toxicity of 3400 chemicals to fish (Part 1). Toxicity of 1085 chemicals to fish (Part 2)

    SciTech Connect

    Wood, E.M.; Hollis, E.H.; Lennon, R.E.

    1987-08-01

    The document, containing data on the toxicity of chemicals to fish, is in two parts. Part 1 consists of a 1953 study by E.M. Wood, U.S. Fish and Wildlife Service, Kearneysville, West Virginia. Data are compiled on over 3400 Chemicals (mostly organic compounds) which were tested using trout, bluegill, yellow perch, and goldfish, at a 5 mg/L screening concentration. Those compounds producing toxicity at 5 mg/L were tested further at lower concentrations. Part 2 contains data developed during a 1954 study by E.H. Hollis and R.E. Lennon at the Kearneysville laboratory using the same fish toxicity screening test protocols. Parts 1 and 2 are published here for the first time. These documents were prepared at the National Fisheries Research Center, U.S. Fish and Wildlife Service Laboratory, La Crosse, Wisconsin, from original records. A preface has been prepared by R.L. Lipnick, Office of Toxic substances, EPA, reviewing the use of these data in the development of structure-activity relationships and quantitative structure-activity relationships.

  17. 6 Million Americans Drink Water Tainted with Toxic Chemicals

    MedlinePlus

    ... news/fullstory_160327.html 6 Million Americans Drink Water Tainted With Toxic Chemicals: Report Many systems contain ... unsafe levels of dangerous chemicals in their drinking water that may trigger a host of health problems, ...

  18. Chemical composition of lunar material.

    PubMed

    Maxwell, J A; Abbey, S; Champ, W H

    1970-01-30

    Chemical and emission spectrographic analyses of three Apollo 11 samples, 10017-29, 10020-30, and 10084-132, are given. Major and minor constituents were determined both by conventional rock analysis methods and by a new composite scheme utilizing a lithium fluoborate method for dissolution of the samples and atomic absorption spectroscopy and colorimetry. Trace constituents were determined by optical emission spectroscopy involving a d-c arc, air-jet controlled.

  19. Exposure Science for Chemical Prioritization and Toxicity Testing

    EPA Science Inventory

    Currently, a significant research effort is underway to apply new technologies to screen and prioritize chemicals for toxicity testing as well as to improve understanding of toxicity pathways (Dix et al. 2007, Toxicol Sci; NRC, 2007, Toxicity Testing in the 21st Century; Collins ...

  20. GENE INDUCTION STUDIES AND TOXICITY OF CHEMICAL MIXTURES

    EPA Science Inventory

    As part of its mixtures program the Agency for Toxic Substances and Disease Registry (ATSDR) supports in vitro and limited in vivo toxicity testing to further our understanding of the toxicity and health effects of chemical mixtures. There are increasing concerns that environment...

  1. 48 CFR 52.223-14 - Toxic Chemical Release Reporting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... not manufacture, process, or otherwise use any toxic chemicals listed in 40 CFR 372.65; (2) The... established under section 313(f) of EPCRA, 42 U.S.C. 11023(f) (including the alternate thresholds at 40 CFR... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Toxic Chemical...

  2. Toxic Chemical Exposure in Schools: Our Children at Risk.

    ERIC Educational Resources Information Center

    Sterling, Peter; Paquette, Nicole

    Asserting that toxic chemicals can be found throughout school grounds in pesticides, building materials, school supplies, cleaning products, office equipment, and personal care products, this reports details the prevalence of toxic chemicals within schools and recommends methods for reducing exposure. Following an executive summary, the report…

  3. Toxic chemical considerations for tank farm releases. Revision 1

    SciTech Connect

    Van Keuren, J.C.

    1995-11-01

    This document provides a method of determining the toxicological consequences of accidental releases from Hanford Tank Farms. A determination was made of the most restrictive toxic chemicals that are expected to be present in the tanks. Concentrations were estimated based on the maximum sample data for each analyte in all the tanks in the composite. Composite evaluated were liquids and solids from single shell tanks, double shell tanks, flammable gas watch list tanks, as well as all solids, all liquids, head space gases, and 241-C-106 solids. A sum of fractions of the health effects was computed for each composite for unit releases based emergency response planning guidelines (ERPGs). Where ERPGs were not available for chemical compounds of interest, surrogate guidelines were established. The calculation method in this report can be applied to actual release scenarios by multiplying the sum of fractions by the release rate for continuous releases, or the release amount for puff releases. Risk guidelines are met if the product is less than for equal to one.

  4. DETECTION OF TOXICANT(S) ON BUILDING SURFACES FOLLOWING CHEMICAL ATTACK

    EPA Science Inventory

    A critical step prior to reoccupation of any facility following a chemical attack is monitoring for toxic compounds on surfaces within that facility. Low level detection of toxicant(s) is necessary to ensure that these compounds have been eliminated after building decontaminatio...

  5. Mechanism of concentration addition toxicity: they are different for nonpolar narcotic chemicals, polar narcotic chemicals and reactive chemicals.

    PubMed

    Lin, Zhifen; Du, Jianwei; Yin, Kedong; Wang, Liansheng; Yu, Hongxia

    2004-03-01

    According to the toxicity mechanism of the individual chemicals, the concentration addition toxicity mechanism is revealed for nonpolar-narcotic-chemical mixtures, polar-narcotic-chemical mixtures and reactive-chemical mixtures, respectively. For nonpolar-narcotic-chemical mixtures, the partitioning of individual chemicals from water to biophase was determined, and the result shows that their concentration additive effect results from no competitive partitioning among individual chemicals. For polar-narcotic-chemical mixtures, their toxicity are contributed by two factors (the total baseline toxicity and the hydrogen bond donor activity of individual chemicals), and it is the concentration additive effect for either of these two factors that leads to their concentration addition toxicity. In addition, the interactions between the reactive chemicals and the biological macromolecules are discussed thoroughly. The results suggest that the net effect of these interactions is zero, and it is this zero net effect that leads to the concentration addition toxicity mechanism for reactive-chemical mixtures.

  6. Chemical composition and acidity of size-fractionated inorganic aerosols of 2013-14 winter haze in Shanghai and associated health risk of toxic elements

    NASA Astrophysics Data System (ADS)

    Behera, Sailesh N.; Cheng, Jinping; Huang, Xian; Zhu, Qiongyu; Liu, Ping; Balasubramanian, Rajasekhar

    2015-12-01

    The severe winter haze episode that occurred in Shanghai from December 2013 to January 2014, characterized by elevated levels of particulate matter (PM), received considerable international attention because of its impacts on public health and disruption of day-to-day activities. To examine the characteristics of PM during this haze episode and to assess the chemistry behind formation of secondary inorganic aerosols (SIA) and associated health impacts due to exposure of toxic elements, we characterized eight water soluble inorganic (WSI) ions and twenty four trace elements in twelve size-fractionated PM (10 nm-9.9 μm). The average mass concentrations of coarse (1.8 μm < Dp < 9.9 μm), fine (Dp < 2.5 μm), ultrafine (0.01 μm < Dp < 0.10 μm) and nano (0.01 μm < Dp < 0.056 μm) particles during hazy days were 2.8, 5.2, 5.3 and 5.1 times higher than those during non-hazy days, respectively. The in-situ pH (pHIS), as predicted by the Aerosol Inorganic Model (AIM-IV) in all sizes of PM, was observed to be lower during hazy days (average of -0.64) than that during non-hazy days (average of -0.29); there was an increased acidity in haze aerosols. Based on the measured concentrations of particulate-bound toxic elements, health risk assessment was conducted, which revealed that the excess lifetime carcinogenic risk to individuals exposed to fine particles under haze events increased significantly (P < 0.05) to 69 ± 18 × 10-6 compared to non-hazy days (34 ± 10 × 10-6). The qualitative source attribution analysis suggested that the occurrence of haze could be due to a combination of increased emissions of PM from multiple anthropogenic sources followed by its accumulation under unfavourable meteorological conditions with lower mixing heights and less wind speeds and the formation of secondary aerosols.

  7. Comparison of the radiological and chemical toxicity of lead

    SciTech Connect

    Beitel, G.A.; Mott, S.

    1995-03-01

    This report estimates the worst-case radiological dose to an individual from ingested lead containing picocurie levels of radionuclides and then compares the calculated radiological health effects to the chemical toxic effects from that same lead. This comparison provides an estimate of the consequences of inadvertently recycling, in the commercial market, lead containing nominally undetectable concentrations of radionuclides. Quantitative expressions for the radiological and chemical toxicities of lead are based on concentrations of lead in the blood stream. The result shows that the chemical toxicity of lead is a greater health hazard, by orders of magnitude, than any probable companion radiation dose.

  8. Acute toxicity handbook of chemicals to estuarine organisms

    SciTech Connect

    Mayer, F.L.

    1987-04-01

    All acute toxicity data developed by the Gulf Breeze Environmental Research Laboratory, U.S. Environmental Protection Agency, since 1961 were evaluated for quality. A data base was established for 1175 tests with 197 chemicals and 52 species of estuarine organisms. The chemicals represent all major groups of pesticides, as well as numerous industrial and inorganic chemicals.

  9. THE TOXCAST PROGRAM FOR PRIORITIZING TOXICITY TESTING OF ENVIRONMENTAL CHEMICALS

    EPA Science Inventory

    The United States Environmental Protection Agency (EPA) is developing methods for utilizing computational chemistry, high-throughput screening (HTS) and various toxicogenomic technologies to predict potential for toxicity and prioritize limited testing resources towards chemicals...

  10. SIMULATION MODELS FOR ENVIRONMENTAL MULTIMEDIA ANALYSIS OF TOXIC CHEMICALS

    EPA Science Inventory

    Multimedia understanding of pollutant behavior in the environment is of particular concern for chemicals that are toxic and are subject to accumulation in the environmental media (air, soil, water, vegetation) where biota and human exposure is significant. Multimedia simulation ...

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

    PubMed

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

    2014-04-01

    Heavy fuel oil (HFO) spills account for approximately 60% of ship-source oil spills and are up to 50 times more toxic than medium and light crude oils. Heavy fuel oils contain elevated concentrations of polycyclic aromatic hydrocarbons (PAHs) and alkyl-PAHs, known to be toxic to fish; however, little direct characterization of HFO toxicity has been reported. An effects-driven chemical fractionation was conducted on HFO 7102 to separate compounds with similar chemical and physical properties, including toxicity, to isolate the groups of compounds most toxic to trout embryos. After each separation, toxicity tests directed the next phase of fractionation, and gas chromatography-mass spectrometry analysis correlated composition with toxicity, with a focus on PAHs. Low-temperature vacuum distillation permitted the separation of HFO into 3 fractions based on boiling point ranges. The most toxic of these fractions underwent wax precipitation to remove long-chain n-alkanes. The remaining PAH-rich extract was further separated using open column chromatography, which provided distinct fractions that were grouped according to increasing aromatic ring count. The most toxic of these fractions was richest in PAHs and alkyl-PAHs. The results of the present study were consistent with previous crude oil studies that identified PAH-rich fractions as the most toxic. PMID:24375845

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

    PubMed

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

    2014-04-01

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

  13. Predicting microbial toxicity of nonuniform multicomponent mixtures of organic chemicals

    SciTech Connect

    Peace, J.; Daniel, D.; Nirmalakhandan, N.; Egemen, E.

    1997-04-01

    Three schemes proposed in the literature for analyzing joint toxic effects of multicomponent mixtures on fish, namely the additivity index (AI), the mixture toxicity index (MTI), and the similarity parameter ({lambda}) are evaluated in this study for microbial toxicity. A new approach is proposed to establish acceptance limits for the similarity parameter, {lambda}, based on experimental errors and uncertainties. Quantitative structure activity relationship (QSAR) techniques are then used to develop a model to predict the concentrations of components in mixtures that would jointly cause 50% inhibition of microbial respiration. The application of this approach is demonstrated on the experimental toxicity data of six eight-component organic chemical mixtures on microorganisms.

  14. SCREENING FOR TOXIC INDUSTRIAL CHEMICALS USING SEMIPERMEABLE MEMBRANE DEVICES WITH RAPID TOXICITY ASSAYS

    EPA Science Inventory

    A time-integrated sampling device interfaced with two toxicity-based assays is reported for monitoring volatile toxic industrial chemicals (TICs). Semipermeable membrane devices (SPMDs) using dimethylsulfoxide (DMSO) as the fill solvent accumulated each of 17 TICs from the vapor...

  15. Meta-analysis of toxicity and teratogenicity of 133 chemicals from zebrafish developmental toxicity studies

    EPA Science Inventory

    Zebrafish developmental toxicity testing is an emerging field, which faces considerable challenges regarding data meta-analysis and the establishment of standardized test protocols. Here, we present an initial correlation study on toxicity of 133 chemicals based on data in the li...

  16. SIMULATING METABOLISM OF XENOBIOTIC CHEMICALS AS A PREDICTOR OF TOXICITY

    EPA Science Inventory

    EPA is faced with long lists of chemicals that need to be assessed for hazard. A major gap in evaluating chemical risk is accounting for metabolic activation resulting in increased toxicity. The goals of this project are to develop a capability to forecast the metabolism of xenob...

  17. EPA'S TOXCAST PROGRAM FOR PREDICTING TOXICITY AND PRIORITIZING ENVIRONMENTAL CHEMICALS

    EPA Science Inventory

    ToxCast is a research program to predict or forecast toxicity by evaluating a broad spectrum of chemicals and effects; physical-chemical properties, predicted bioactivities, HTS and cell-based assays, and genomics. Data will be interpretively linked to known or predicted toxicol...

  18. Sediment toxicity in Boston Harbor: Magnitude, extent, and relationships with chemical toxicants. Technical memo

    SciTech Connect

    Long, E.R.; Sloane, G.M.; Carr, R.S.; Scott, K.J.; Thursby, G.B.

    1996-06-01

    A survey of the toxicity of sediments throughout Boston Harbor and vicinity was conducted by NOAA`s National Status and Trends (NS&T) Program. The objectives of the survey were to determine the magnitude and spatial extent of toxicity and the relationship between measures of toxicity and the concentrations of chemical toxicants in the sediments. Multiple toxicity tests were performed including: an amphipod survival test performed with whole sediments, a microbial bioluminescence test performed with organic solvent extracts of the sediments, and sea urchin fertilization and embryological development tests performed with the pore waters extracted from the sediments. Chemical analyses were performed on selected samples for trace metals, polynuclear aromatic hydrcarbons, chlorinated pesticides, PCBs, and butyltins.

  19. Environmental sentinel biomonitors: integrated response systems for monitoring toxic chemicals

    NASA Astrophysics Data System (ADS)

    van der Schalie, William H.; Reuter, Roy; Shedd, Tommy R.; Knechtges, Paul L.

    2002-02-01

    Operational environments for military forces are becoming potentially more dangerous due to the increased number, use, and misuse of toxic chemicals across the entire range of military missions. Defense personnel may be exposed to harmful chemicals as a result of industrial accidents or intentional or unintentional action of enemy, friendly forces, or indigenous populations. While there has been a significant military effort to enable forces to operate safely and survive and sustain operations in nuclear, biological, chemical warfare agent environments, until recently there has not been a concomitant effort associated with potential adverse health effects from exposures of deployed personnel to toxic industrial chemicals. To provide continuous real-time toxicity assessments across a broad spectrum of individual chemicals or chemical mixtures, an Environmental Sentinel Biomonitor (ESB) system concept is proposed. An ESB system will integrate data from one or more platforms of biologically-based systems and chemical detectors placed in the environment to sense developing toxic conditions and transmit time-relevant data for use in risk assessment, mitigation, and/or management. Issues, challenges, and next steps for the ESB system concept are described, based in part on discussions at a September 2001 workshop sponsored by the U.S. Army Center for Environmental Health Research.

  20. Compositions and methods for removal of toxic metals and radionuclides

    NASA Technical Reports Server (NTRS)

    Cuero, Raul G. (Inventor); McKay, David S. (Inventor)

    2007-01-01

    The present invention relates to compositions and methods for the removal of toxic metals or radionuclides from source materials. Toxic metals may be removed from source materials using a clay, such as attapulgite or highly cationic bentonite, and chitin or chitosan. Toxic metals may also be removed using volcanic ash alone or in combination with chitin or chitosan. Radionuclides may be removed using volcanic ash alone or in combination with chitin or chitosan.

  1. The Respiratory Toxicity of Chemical Warefare Agents

    EPA Science Inventory

    Inhalation is one of the most important routes of exposure for chemical warfare agents (CWAs) and thus, the lung remains a critical target of injury. Depending on the mode of action by which the CWAs cause injury, the nature of injury, the location being impacted within the respi...

  2. An expert system for prediction of chemical toxicity

    USGS Publications Warehouse

    Hickey, James P.; Aldridge, Andrew J.; Passino-Reader, Dora R.; Frank, Anthony M.

    1992-01-01

    The National Fisheries Research Center- Great Lakes has developed an interactive computer program that uses the structure of an organic molecule to predict its acute toxicity to four aquatic species. The expert system software, written in the muLISP language, identifies the skeletal structures and substituent groups of an organic molecule from a user-supplied standard chemical notation known as a SMILES string, and then generates values for four solvatochromic parameters. Multiple regression equations relate these parameters to the toxicities (expressed as log10LC50s and log10EC50s, along with 95% confidence intervals) for four species. The system is demonstrated by prediction of toxicity for anilide-type pesticides to the fathead minnow (Pimephales promelas). This software is designed for use on an IBM-compatible personal computer by personnel with minimal toxicology background for rapid estimation of chemical toxicity. The system has numerous applications, with much potential for use in the pharmaceutical industry

  3. Comparison of Chemical Composition of Complex Disinfection Byproduct (DBP) Mixtures Produced by Different Treatment Methods

    EPA Science Inventory

    Analyses of the chemical composition of complex DBP mixtures, produced by different drinking water treatment processes, are essential to generate toxicity data required for assessing their risks to humans. For mixture risk assessments, whole mixture toxicology studies generally a...

  4. Comparison of Chemical Composition of Complex Disinfection Byproduct (DBP) Mixtures Produced by Different Treatment Methods - slides

    EPA Science Inventory

    Analyses of the chemical composition of complex DBP mixtures, produced by different drinking water treatment processes, are essential to generate toxicity data required for assessing their risks to humans. For mixture risk assessments, whole mixture toxicology studies generally a...

  5. The relationship bettween composition and toxicity of tannery wastewater.

    PubMed

    Cotman, M; Zagorc-Koncan, J; Zgajnar-Gotvajn, A

    2004-01-01

    Key toxic components have been identified in pre-treated tannery wastewater with fractionation of samples through chemical and physical means (filtration, air stripping, adsorption on activated carbon,...). The goal of each fractionation step was to reduce the toxicity due to a specific group of chemicals and compare the results to the toxicity present in the unaltered sample. Toxicity short-term tests with the invertebrate Daphnia magna and thebacterial luminescence inhibition test with Vibrio fischeri were used in combination with chemical analyses. During the toxicity identification and evaluation fractionation, a portion of the sample was pressure filtered. Treated samples contained less organic pollution and metals and were less toxic especially to Daphnia magna. For the removal of ammonia the second portion of sample was air-stripped at different pH levels. We removed 84% of ammonia at pH 11; the toxicity to both organisms decreased but ammonia did not have a deciding effect on the toxicity of tannery wastewater when the organic load was still present. The most successful procedure for toxicity removal was adsorption on powdered activated carbon. We removed organic pollution detected as COD, organic nitrogen compounds and part of the metals. Zeolite treatment was a little less successful for removing ammonia than air-stripping.

  6. Chemical and Radiological Toxicity of Uranium and Its Compounds

    SciTech Connect

    Tansky, R.R.

    2001-07-26

    The concentration of uranyl nitrate required to deliver the radiation dose limit for soluble uranium compounds is larger than the toxicity-based concentration limits. Therefore, for soluble uranium compounds, health consequences of exposure are primarily due to their chemical toxicity. For insoluble compounds of uranium, health consequences (e.g., fibrosis and/or carcinogenesis of the lung) are primarily due to irradiation of pulmonary tissues from inhaled respirable particles.

  7. Insect-gene-activity detection system for chemical and biological warfare agents and toxic industrial chemicals

    NASA Astrophysics Data System (ADS)

    Mackie, Ryan S.; Schilling, Amanda S.; Lopez, Arturo M.; Rayms-Keller, Alfredo

    2002-02-01

    Detection of multiple chemical and biological weapons (CBW) agents and/or complex mixtures of toxic industrial chemicals (TIC) is imperative for both the commercial and military sectors. In a military scenario, a multi-CBW attack would create confusion, thereby delaying decontamination and therapeutic efforts. In the commercial sector, polluted sites invariably contain a mixture of TIC. Novel detection systems capable of detecting CBW and TIC are sorely needed. While it may be impossible to build a detector capable of discriminating all the possible combinations of CBW, a detection system capable of statistically predicting the most likely composition of a given mixture is within the reach of current emerging technologies. Aquatic insect-gene activity may prove to be a sensitive, discriminating, and elegant paradigm for the detection of CBW and TIC. We propose to systematically establish the expression patterns of selected protein markers in insects exposed to specific mixtures of chemical and biological warfare agents to generate a library of biosignatures of exposure. The predicting capabilities of an operational library of biosignatures of exposures will allow the detection of emerging novel or genetically engineered agents, as well as complex mixtures of chemical and biological weapons agents. CBW and TIC are discussed in the context of war, terrorism, and pollution.

  8. Troubleshooting methods for toxicity testing of airborne chemicals in vitro.

    PubMed

    Bakand, Shahnaz; Hayes, Amanda

    2010-01-01

    Toxicology studies of adverse effects induced by inhaled chemicals are technically challenging, due to the requirement of highly controlled experimental conditions needed to achieve reproducible and comparable results. Therefore, many considerations must be fulfilled before adopting in vitro bioassay test systems for toxicity screening of airborne materials. However, recent methodological and technical breakthroughs of in vitro methods have the potential to fulfil the essential requirements of toxicity testing for airborne chemicals. Technology has now become available that allows cells to be cultured on permeable microporous membranes in transwell or snapwell inserts providing a very close contact between target cells and test atmospheres to study the cellular interactions caused by airborne chemical exposures without any interfering culture medium. Using a direct exposure technique at the air-liquid interface, target cells can be continuously exposed to airborne chemicals on their apical side, while being nourished from their basolateral side. Test atmospheres with different physicochemical characteristics such as gases, vapours, solid and liquid aerosols and more recently nanoaerosols, can be delivered into human target cells using static and/or direct dynamic exposure methods. Therefore, toxicological risk assessments of airborne chemicals and even complex atmospheres can be achieved using in vitro test methods in parallel with real-time air monitoring techniques to fulfil the general regulatory requirements of newly developed chemical or pharmaceutical products with the potential for inhalational exposure. In this review current toxicological methods for toxicity testing of inhaled chemicals are presented. Further, to demonstrate the potential application of in vitro methods for studying inhalation toxicity, more advanced exposure techniques developed for toxicity screening of airborne chemicals are discussed.

  9. Predicting modes of toxic action from chemical structure: an overview.

    PubMed

    Bradbury, S P

    1994-01-01

    In the field of environmental toxicology, and especially aquatic toxicology, quantitative structure activity relationships (QSARs) have developed as scientifically-credible tools for predicting the toxicity of chemicals when little or no empirical data are available. A basic and fundamental understanding of toxicological principles has been considered crucial to the continued acceptance and application of these techniques as biologically relevant. As a consequence, there has been an evolution of QSAR development and application from that of a chemical-class perspective to one that is more consistent with assumptions regarding modes of toxic action. The assessment of a compound's likely mode of toxic action is critical for a correct QSAR selection; incorrect mode of action-based QSAR selections can result in 10- to 1000-fold errors in toxicity predictions. The establishment of toxicologically-credible techniques to assess mode of toxic action from chemical structure requires toxicodynamic knowledge bases that are clearly defined with regard to exposure regimes and biological models/endpoints and based on compounds that adequately span the diversity of chemicals anticipated for future applications. With such knowledge bases classification systems, including rule-based experts systems, have been established for use in predictive aquatic toxicology applications. PMID:8790641

  10. Effects of toxic metals and chemicals on biofilm and biocorrosion.

    PubMed

    Fang, Herbert H P; Xu, Li-Chong; Chan, Kwong-Yu

    2002-11-01

    Microbes in marine biofilms aggregated into clusters and increased the production of extracellular polymeric substances (EPS), by over 100% in some cases, when the seawater media containing toxic metals and chemicals, such as Cd(II), Cu(II), Pb(II), Zn(II), AI(III), Cr(III), glutaraldehyde, and phenol. The formation of microbial cluster and the increased production of EPS, which contained 84-92% proteins and 8-16% polysaccharides, accelerated the corrosion of the mild steel. However, there was no quantitative relationship between the degree of increased corrosion and the toxicity of metals/chemicals towards sulfate-reducing bacteria, or the increased EPS production.

  11. Lead Toxicity to the Performance, Viability, And Community Composition of Activated Sludge Microorganisms

    SciTech Connect

    Yuan, L; Zhi, W; Liu, YS; Karyala, S; Vikesland, PJ; Chen, X; Zhang, HS

    2015-01-20

    Lead (Pb) is a prominent toxic metal in natural and engineered systems. Current knowledge on Pb toxicity to the activated sludge has been limited to short-term (<= 24 h) toxicity. The effect of extended Pb exposure on process performance, bacterial viability, and community compositions remains unknown. We quantified the 24-h and 7-day Pb toxicity to chemical oxygen demand (COD) and NH3-N removal, bacterial viability, and community compositions using lab-scale experiments. Our results showed that 7-day toxicity was significantly higher than the short-term 24-h toxicity. Ammonia-oxidizing bacteria were more susceptible than the heterotrophs to Pb toxicity. The specific oxygen uptake rate responded quickly to Pb addition and could serve as a rapid indicator for detecting Pb pollutions. Microbial viability decreased linearly with the amount of added Pb at extended exposure. The bacterial community diversity was markedly reduced with elevated Pb concentrations. Surface analysis suggested that the adsorbed form of Pb could have contributed to its toxicity along with the dissolved form. Our study provides for the first time a systematic investigation of the effect of extended exposure of Pb on the performance and microbiology of aerobic treatment processes, and it indicates that long-term Pb toxicity has been underappreciated by previous studies.

  12. Lead toxicity to the performance, viability, and community composition of activated sludge microorganisms.

    PubMed

    Yuan, Li; Zhi, Wei; Liu, Yangsheng; Karyala, Saikumar; Vikesland, Peter J; Chen, Xi; Zhang, Husen

    2015-01-20

    Lead (Pb) is a prominent toxic metal in natural and engineered systems. Current knowledge on Pb toxicity to the activated sludge has been limited to short-term (≤24 h) toxicity. The effect of extended Pb exposure on process performance, bacterial viability, and community compositions remains unknown. We quantified the 24-h and 7-day Pb toxicity to chemical oxygen demand (COD) and NH3–N removal, bacterial viability, and community compositions using lab-scale experiments. Our results showed that 7-day toxicity was significantly higher than the short-term 24-h toxicity. Ammonia-oxidizing bacteria were more susceptible than the heterotrophs to Pb toxicity. The specific oxygen uptake rate responded quickly to Pb addition and could serve as a rapid indicator for detecting Pb pollutions. Microbial viability decreased linearly with the amount of added Pb at extended exposure. The bacterial community diversity was markedly reduced with elevated Pb concentrations. Surface analysis suggested that the adsorbed form of Pb could have contributed to its toxicity along with the dissolved form. Our study provides for the first time a systematic investigation of the effect of extended exposure of Pb on the performance and microbiology of aerobic treatment processes, and it indicates that long-term Pb toxicity has been underappreciated by previous studies. PMID:25536278

  13. Morphological and Chemical Mechanisms of Elongated Mineral Particle Toxicities

    PubMed Central

    Aust, Ann E.; Cook, Philip M.; Dodson, Ronald F.

    2011-01-01

    Much of our understanding regarding the mechanisms for induction of disease following inhalation of respirable elongated mineral particles (REMP) is based on studies involving the biological effects of asbestos fibers. The factors governing the disease potential of an exposure include duration and frequency of exposures; tissue-specific dose over time; impacts on dose persistence from in vivo REMP dissolution, comminution, and clearance; individual susceptibility; and the mineral type and surface characteristics. The mechanisms associated with asbestos particle toxicity involve two facets for each particle's contribution: (1) the physical features of the inhaled REMP, which include width, length, aspect ratio, and effective surface area available for cell contact; and (2) the surface chemical composition and reactivity of the individual fiber/elongated particle. Studies in cell-free systems and with cultured cells suggest an important way in which REMP from asbestos damage cellular molecules or influence cellular processes. This may involve an unfortunate combination of the ability of REMP to chemically generate potentially damaging reactive oxygen species, through surface iron, and the interaction of the unique surfaces with cell membranes to trigger membrane receptor activation. Together these events appear to lead to a cascade of cellular events, including the production of damaging reactive nitrogen species, which may contribute to the disease process. Thus, there is a need to be more cognizant of the potential impact that the total surface area of REMP contributes to the generation of events resulting in pathological changes in biological systems. The information presented has applicability to inhaled dusts, in general, and specifically to respirable elongated mineral particles. PMID:21534085

  14. Toxicity of fishery chemicals to the asiatic clam, Corbicula manilensis

    USGS Publications Warehouse

    Chandler, Jack H.; Marking, L.L.

    1979-01-01

    The Asiatic clam (Corbicula manilensis), a species introduced into U. S. waters, has spread rapidly, and its ability to survive, reproduce, and spread has caused concern. Aquatic biologists suspect that the clams may crowd out indigenous mollusks, and the animals sometimes plug water intakes and leave shell deposits that interfere with sand and gravel operations. The toxicity of 20 commonly used fishery chemicals to the Asiatic clam was determined to evaluate hazards to a nontarget aquatic invertebrate and to assess the potential of the chemicals for controlling clam populations. Among six piscicides and two lampricides tested, antimycin was most toxic to the clam; the 96-h LC50 was 0.065 mg/L. Among three therapeutants and two disinfectants tested, nifurpirinol was the most toxic; the 96-h LC50 was 7.60 mg/L. All of the compounds were less toxic to the clam than to fish. As a nontarget organism, this clam would be safe in water treated with any of the tested fishery chemicals at recommended use pattern concentrations. None of the chemicals have potential for controlling unwanted populations of these clams.

  15. Relevancy in Basic Courses: Considering Toxic Chemical Disposal.

    ERIC Educational Resources Information Center

    Sollimo, Vincent J.

    1985-01-01

    A 2-week unit on toxic chemical waste disposal is used in a physical science course for nonscience majors. Descriptions of the unit, supplementary student activities, and student library project are provided. Also provided are selected student responses to a five-question survey on the unit. (JN)

  16. The Chemical Composition of Maple Syrup

    ERIC Educational Resources Information Center

    Ball, David W.

    2007-01-01

    Maple syrup is one of several high-sugar liquids that humans consume. However, maple syrup is more than just a concentrated sugar solution. Here, we review the chemical composition of maple syrup. (Contains 4 tables and 1 figure.)

  17. Molecular mechanisms of aldehyde toxicity: a chemical perspective.

    PubMed

    LoPachin, Richard M; Gavin, Terrence

    2014-07-21

    Aldehydes are electrophilic compounds to which humans are pervasively exposed. Despite a significant health risk due to exposure, the mechanisms of aldehyde toxicity are poorly understood. This ambiguity is likely due to the structural diversity of aldehyde derivatives and corresponding differences in chemical reactions and biological targets. To gain mechanistic insight, we have used parameters based on the hard and soft, acids and bases (HSAB) theory to profile the different aldehyde subclasses with respect to electronic character (softness, hardness), electrophilic reactivity (electrophilic index), and biological nucleophilic targets. Our analyses indicate that short chain aldehydes and longer chain saturated alkanals are hard electrophiles that cause toxicity by forming adducts with hard biological nucleophiles, e.g., primary nitrogen groups on lysine residues. In contrast, α,β-unsaturated carbonyl derivatives, alkenals, and the α-oxoaldehydes are soft electrophiles that preferentially react with soft nucleophilic thiolate groups on cysteine residues. The aldehydes can therefore be grouped into subclasses according to common electronic characteristics (softness/hardness) and molecular mechanisms of toxicity. As we will discuss, the toxic potencies of these subgroups are generally related to corresponding electrophilicities. For some aldehydes, however, predictions of toxicity based on electrophilicity are less accurate due to inherent physicochemical variables that limit target accessibility, e.g., steric hindrance and solubility. The unsaturated aldehydes are also members of the conjugated type-2 alkene chemical class that includes α,β-unsaturated amide, ketone, and ester derivatives. Type-2 alkenes are electrophiles of varying softness and electrophilicity that share a common mechanism of toxicity. Therefore, exposure to an environmental mixture of unsaturated carbonyl derivatives could cause "type-2 alkene toxicity" through additive interactions

  18. Biomedical Platforms Based on Composite Nanomaterials and Cellular Toxicity

    NASA Astrophysics Data System (ADS)

    Bellucci, Stefano; Bergamaschi, A.; Bottini, M.; Magrini, A.; Mustelin, T.

    2007-03-01

    Carbon nanotubes possess unique chemical, physical, optical, and magnetic properties, which make them suitable for many uses in industrial products and in the field of nanotechnology, including nanomedicine. We describe fluorescent nanocomposites for use in biosensors or nanoelectronics. Then we describe recent results on the issue of cytotoxicity of carbon nanotubes obtained in our labs. Silica nanoparticles have been widely used for biosensing and catalytic applications due to their large surface area-to-volume ratio, straightforward manufacture, and the compatibility of silica chemistry with covalent coupling of biomolecules. Carbon nanotubes-composite materials, such as those based on Carbon nanotubes bound to nanoparticles, are suitable, in order to tailor Carbon nanotubes properties for specific applications. We present a tunable synthesis of Multi Wall Carbon nanotubes-Silica nanoparticles. The control of the nanotube morphology and the bead size, coupled with the versatility of silica chemistry, makes these structures an excellent platform for the development of biosensors (optical, magnetic and catalytic applications). We describe the construction and characterization of supramolecular nanostructures consisting of ruthenium-complex luminophores, directly grafted onto short oxidized single-walled carbon nanotubes or physically entrapped in silica nanobeads, which had been covalently linked to short oxidized single-walled carbon nanotubes or hydrophobically adsorbed onto full-length multi-walled carbon nanotubes. These structures have been evaluated as potential electron-acceptor complexes for use in the fabrication of photovoltaic devices, and for their properties as fluorescent nanocomposites for use in biosensors or nanoelectronics. Finally, we compare the toxicity of pristine and oxidized Multi Walled Carbon nanotubes on human T cells - which would be among the first exposed cell types upon intravenous administration of Carbon nanotubes in therapeutic

  19. Toxicity and composition profiles of solid phase extracts of oil sands process-affected water.

    PubMed

    Yue, Siqing; Ramsay, Bruce A; Wang, Jiaxi; Ramsay, Juliana

    2015-12-15

    After fractionation using sequential solid phase extraction, the presence of toxic components in oil sands process-affected water (OSPW) was detected by the Microtox® acute toxicity assay using effect-directed analysis. The composition of each fraction was determined by high-resolution electrospray ionization-Orbitrap mass spectrometry. Partial least-squares discriminant analysis (PLS-DA) was used to determine which chemical constituents in all seven fractions co-varied most strongly with toxicity. Although O2 compounds with double bond equivalence (DBE) between 3 and 9 positively correlated with toxicity, C15-C18 O2-NAs with DBE=4 (tricyclic structure), as well as C14-C17 O2-NAs with DBE=3 (bicyclic structure), were found to be most likely associated with OSPW toxicity, consistent with published toxicity studies of surrogate NAs. O4, many O3 (i.e. possibly hydroxylated O2 c-NAs) and a few O2 compounds were found to negatively correlate with toxicity. The results demonstrate the utility of the fractionation and the PLS-DA approach for evaluating composition-response relationships in a complex mixture and also contribute to a better understanding of the toxic compounds in OSPW. These findings will help to focus study on the most environmentally significant components in OSPW. PMID:26318810

  20. Yellow phosphorus process to convert toxic chemicals to non-toxic products

    DOEpatents

    Chang, S.G.

    1994-07-26

    The present invention relates to a process for generating reactive species for destroying toxic chemicals. This process first contacts air or oxygen with aqueous emulsions of molten yellow phosphorus. This contact results in rapid production of abundant reactive species such as O, O[sub 3], PO, PO[sub 2], etc. A gaseous or liquid aqueous solution organic or inorganic chemicals is next contacted by these reactive species to reduce the concentration of toxic chemical and result in a non-toxic product. The final oxidation product of yellow phosphorus is phosphoric acid of a quality which can be recovered for commercial use. A process is developed such that the byproduct, phosphoric acid, is obtained without contamination of toxic species in liquids treated. A gas stream containing ozone without contamination of phosphorus containing species is also obtained in a simple and cost-effective manner. This process is demonstrated to be effective for destroying many types of toxic organic, or inorganic, compounds, including polychlorinated biphenyls (PCB), aromatic chlorides, amines, alcohols, acids, nitro aromatics, aliphatic chlorides, polynuclear aromatic compounds (PAH), dyes, pesticides, sulfides, hydroxyamines, ureas, dithionates and the like. 20 figs.

  1. Yellow phosphorus process to convert toxic chemicals to non-toxic products

    DOEpatents

    Chang, Shih-Ger

    1994-01-01

    The present invention relates to a process for generating reactive species for destroying toxic chemicals. This process first contacts air or oxygen with aqueous emulsions of molten yellow phosphorus. This contact results in rapid production of abundant reactive species such as O, O.sub.3, PO, PO.sub.2, etc. A gaseous or liquid aqueous solution organic or inorganic chemicals is next contacted by these reactive species to reduce the concentration of toxic chemical and result in a non-toxic product. The final oxidation product of yellow phosphorus is phosphoric acid of a quality which can be recovered for commercial use. A process is developed such that the byproduct, phosphoric acid, is obtained without contamination of toxic species in liquids treated. A gas stream containing ozone without contamination of phosphorus containing species is also obtained in a simple and cost-effective manner. This process is demonstrated to be effective for destroying many types of toxic organic, or inorganic, compounds, including polychlorinated biphenyls (PCB), aromatic chlorides, amines, alcohols, acids, nitro aromatics, aliphatic chlorides, polynuclear aromatic compounds (PAH), dyes, pesticides, sulfides, hydroxyamines, ureas, dithionates and the like.

  2. Chemical composition of fat and oil products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fats and oils are an important dietary component, and contribute to the nutritional and sensory quality of foods. This chapter focuses on the chemical composition of fats and oils, and how these compositions affect the functional properties of fats and oils in foods. The focus will remain on the mos...

  3. QSAR for toxicity of organic chemicals to luminescent bacteria

    SciTech Connect

    Devillers, J.; Bintein, S.; Karcher, W.

    1994-12-31

    Over the last decade, there have been increasing pressures to review and reduce the use of laboratory animals for toxicity testing. For ethical and economic reasons, various techniques have been developed and proposed as potential alternatives for some of the whole animal toxicity assays. One assay proposed as an alternative to animal testing is the luminescent bacteria toxicity test, provided under the trade name of Microtox{reg_sign} test. This test has been widely used to estimate the toxicity of agricultural, pharmaceutical, and industrial chemicals producing a large amount of valuable toxicity results. Under these conditions, from a critical analysis of the literature, it has been possible to constitute a large data bank of more than 1,000 organic chemicals for deriving a general QSAR model for the Microtox test. Due to the heterogeneity of the data sets, the molecules were described by means of the modified autocorrelation method. The autocorrelation vectors were generated from atomic contributions encoding the hydrophobicity of the molecules. The validity of the model has been widely discussed and its implications in terms of hazard assessment have been also underlined.

  4. Molecular Mechanisms of Aldehyde Toxicity: A Chemical Perspective

    PubMed Central

    2015-01-01

    Aldehydes are electrophilic compounds to which humans are pervasively exposed. Despite a significant health risk due to exposure, the mechanisms of aldehyde toxicity are poorly understood. This ambiguity is likely due to the structural diversity of aldehyde derivatives and corresponding differences in chemical reactions and biological targets. To gain mechanistic insight, we have used parameters based on the hard and soft, acids and bases (HSAB) theory to profile the different aldehyde subclasses with respect to electronic character (softness, hardness), electrophilic reactivity (electrophilic index), and biological nucleophilic targets. Our analyses indicate that short chain aldehydes and longer chain saturated alkanals are hard electrophiles that cause toxicity by forming adducts with hard biological nucleophiles, e.g., primary nitrogen groups on lysine residues. In contrast, α,β-unsaturated carbonyl derivatives, alkenals, and the α-oxoaldehydes are soft electrophiles that preferentially react with soft nucleophilic thiolate groups on cysteine residues. The aldehydes can therefore be grouped into subclasses according to common electronic characteristics (softness/hardness) and molecular mechanisms of toxicity. As we will discuss, the toxic potencies of these subgroups are generally related to corresponding electrophilicities. For some aldehydes, however, predictions of toxicity based on electrophilicity are less accurate due to inherent physicochemical variables that limit target accessibility, e.g., steric hindrance and solubility. The unsaturated aldehydes are also members of the conjugated type-2 alkene chemical class that includes α,β-unsaturated amide, ketone, and ester derivatives. Type-2 alkenes are electrophiles of varying softness and electrophilicity that share a common mechanism of toxicity. Therefore, exposure to an environmental mixture of unsaturated carbonyl derivatives could cause “type-2 alkene toxicity” through additive interactions

  5. Toxic neuropathies: Mechanistic insights based on a chemical perspective.

    PubMed

    LoPachin, Richard M; Gavin, Terrence

    2015-06-01

    2,5-Hexanedione (HD) and acrylamide (ACR) are considered to be prototypical among chemical toxicants that cause central-peripheral axonopathies characterized by distal axon swelling and degeneration. Because the demise of distal regions was assumed to be causally related to the onset of neurotoxicity, substantial effort was devoted to deciphering the respective mechanisms. Continued research, however, revealed that expression of the presumed hallmark morphological features was dependent upon the daily rate of toxicant exposure. Indeed, many studies reported that the corresponding axonopathic changes were late developing effects that occurred independent of behavioral and/or functional neurotoxicity. This suggested that the toxic axonopathy classification might be based on epiphenomena related to dose-rate. Therefore, the goal of this mini-review is to discuss how quantitative morphometric analyses and the establishment of dose-dependent relationships helped distinguish primary, mechanistically relevant toxicant effects from non-specific consequences. Perhaps more importantly, we will discuss how knowledge of neurotoxicant chemical nature can guide molecular-level research toward a better, more rational understanding of mechanism. Our discussion will focus on HD, the neurotoxic γ-diketone metabolite of the industrial solvents n-hexane and methyl-n-butyl ketone. Early investigations suggested that HD caused giant neurofilamentous axonal swellings and eventual degeneration in CNS and PNS. However, as our review will point out, this interpretation underwent several iterations as the understanding of γ-diketone chemistry improved and more quantitative experimental approaches were implemented. The chemical concepts and design strategies discussed in this mini-review are broadly applicable to the mechanistic studies of other chemicals (e.g., n-propyl bromine, methyl methacrylate) that cause toxic neuropathies.

  6. Identifying and designing chemicals with minimal acute aquatic toxicity

    PubMed Central

    Kostal, Jakub; Voutchkova-Kostal, Adelina; Anastas, Paul T.; Zimmerman, Julie Beth

    2015-01-01

    Industrial ecology has revolutionized our understanding of material stocks and flows in our economy and society. For this important discipline to have even deeper impact, we must understand the inherent nature of these materials in terms of human health and the environment. This paper focuses on methods to design synthetic chemicals to reduce their intrinsic ability to cause adverse consequence to the biosphere. Advances in the fields of computational chemistry and molecular toxicology in recent decades allow the development of predictive models that inform the design of molecules with reduced potential to be toxic to humans or the environment. The approach presented herein builds on the important work in quantitative structure–activity relationships by linking toxicological and chemical mechanistic insights to the identification of critical physical–chemical properties needed to be modified. This in silico approach yields design guidelines using boundary values for physiochemical properties. Acute aquatic toxicity serves as a model endpoint in this study. Defining value ranges for properties related to bioavailability and reactivity eliminates 99% of the chemicals in the highest concern for acute aquatic toxicity category. This approach and its future implementations are expected to yield very powerful tools for life cycle assessment practitioners and molecular designers that allow rapid assessment of multiple environmental and human health endpoints and inform modifications to minimize hazard. PMID:24639521

  7. Identifying and designing chemicals with minimal acute aquatic toxicity.

    PubMed

    Kostal, Jakub; Voutchkova-Kostal, Adelina; Anastas, Paul T; Zimmerman, Julie Beth

    2015-05-19

    Industrial ecology has revolutionized our understanding of material stocks and flows in our economy and society. For this important discipline to have even deeper impact, we must understand the inherent nature of these materials in terms of human health and the environment. This paper focuses on methods to design synthetic chemicals to reduce their intrinsic ability to cause adverse consequence to the biosphere. Advances in the fields of computational chemistry and molecular toxicology in recent decades allow the development of predictive models that inform the design of molecules with reduced potential to be toxic to humans or the environment. The approach presented herein builds on the important work in quantitative structure-activity relationships by linking toxicological and chemical mechanistic insights to the identification of critical physical-chemical properties needed to be modified. This in silico approach yields design guidelines using boundary values for physiochemical properties. Acute aquatic toxicity serves as a model endpoint in this study. Defining value ranges for properties related to bioavailability and reactivity eliminates 99% of the chemicals in the highest concern for acute aquatic toxicity category. This approach and its future implementations are expected to yield very powerful tools for life cycle assessment practitioners and molecular designers that allow rapid assessment of multiple environmental and human health endpoints and inform modifications to minimize hazard.

  8. Toxicity testing in the 21st century beyond environmental chemicals.

    PubMed

    Rovida, Costanza; Asakura, Shoji; Daneshian, Mardas; Hofman-Huether, Hana; Leist, Marcel; Meunier, Leo; Reif, David; Rossi, Anna; Schmutz, Markus; Valentin, Jean-Pierre; Zurlo, Joanne; Hartung, Thomas

    2015-01-01

    After the publication of the report titled Toxicity Testing in the 21st Century - A Vision and a Strategy, many initiatives started to foster a major paradigm shift for toxicity testing - from apical endpoints in animal-based tests to mechanistic endpoints through delineation of pathways of toxicity (PoT) in human cell based systems. The US EPA has funded an important project to develop new high throughput technologies based on human cell based in vitro technologies. These methods are currently being incorporated into the chemical risk assessment process. In the pharmaceutical industry, the efficacy and toxicity of new drugs are evaluated during preclinical investigations that include drug metabolism, pharmacokinetics, pharmacodynamics and safety toxicology studies. The results of these studies are analyzed and extrapolated to predict efficacy and potential adverse effects in humans. However, due to the high failure rate of drugs during the clinical phases, a new approach for a more predictive assessment of drugs both in terms of efficacy and adverse effects is getting urgent. The food industry faces the challenge of assessing novel foods and food ingredients for the general population, while using animal safety testing for extrapolation purposes is often of limited relevance. The question is whether the latest paradigm shift proposed by the Tox21c report for chemicals may provide a useful tool to improve the risk assessment approach also for drugs and food ingredients.

  9. Chemical composition of Martian fines

    NASA Technical Reports Server (NTRS)

    Clark, B. C.; Baird, A. K.; Weldon, R. J.; Tsusaki, D. M.; Schnabel, L.; Candelaria, M. P.

    1982-01-01

    Of the 21 samples acquired for the Viking X-ray fluorescence spectrometer, 17 were analyzed to high precision. Compared to typical terrestrial continental soils and lunar mare fines, the Martian fines are lower in Al, higher in Fe, and much higher in S and Cl concentrations. Protected fines at the two lander sites are almost indistinguishable, but concentration of the element S is somewhat higher at Utopia. Duricrust fragments, successfully acquired only at the Chryse site, invariably contained about 50% higher S than fines. No elements correlate positively with S, except Cl and possibly Mg. A sympathetic variation is found among the triad Si, Al, Ca; positive correlation occurs between Ti and Fe. Sample variabilities are as great within a few meters as between lander locations (4500 km apart), implying the existence of a universal Martian regolith component of constant average composition. The nature of the source materials for the regolith fines must be mafic to ultramafic.

  10. Reactive formulations for a neutralization of toxic industrial chemicals

    SciTech Connect

    Tucker, Mark D.; Betty, Rita G.

    2006-10-24

    Decontamination formulations for neutralization of toxic industrial chemicals, and methods of making and using same. The formulations are effective for neutralizing malathion, hydrogen cyanide, sodium cyanide, butyl isocyanate, carbon disulfide, phosgene gas, capsaicin in commercial pepper spray, chlorine gas, anhydrous ammonia gas; and may be effective at neutralizing hydrogen sulfide, sulfur dioxide, formaldehyde, ethylene oxide, methyl bromide, boron trichloride, fluorine, tetraethyl pyrophosphate, phosphorous trichloride, arsine, and tungsten hexafluoride.

  11. [Hospital response and medical management in toxic chemical substance disasters].

    PubMed

    Yeh, I-Jeng; Lin, Tzeng-Jih

    2010-06-01

    A hazardous material is defined as any item or agent which has the potential to cause harm to humans, animals, or the environment, either by itself or through interaction with other factors. Toxic chemical substance events are increasingly common events in our modern world. The numerous variables and special equipment involved make effective response to toxic chemical events an especially critical test of hospital emergency response and patient rescue mechanisms. Inadequacies in management could result in disaster - even when only a simple event and minimal error are involved. This article introduces the general medical management algorithm for toxic chemical substance injury and the hospital incident command systems (HICS) developed and currently used by Taiwanese hospitals. Important steps and frequent mistakes made during medical management procedures are further described. The goal of medical care response and emergency units is to prevent catastrophic disasters in the emergency room and their subsequent results. This article further emphasizes correct patient management not only in terms of medical unit effort, but also in terms of cooperation between various relevant organizations including factory-based industrial health and safety systems, multi-factory union defense systems, coordination centers, fire protection and disaster rescue systems, the Environmental Protection Administration and national defense system in order to achieve the most appropriate management. Such coordination, in particular, requires reinforcement in order to ensure readiness for future response needs. PMID:20535674

  12. Toxico-Cheminformatics: New and Expanding Public Resources to Support Chemical Toxicity Assessments

    EPA Science Inventory

    High-throughput screening (HTS) technologies, along with efforts to improve public access to chemical toxicity information resources and to systematize older toxicity studies, have the potential to significantly improve information gathering efforts for chemical assessments and p...

  13. Modification of chemical additives to elastomeric compositions

    NASA Astrophysics Data System (ADS)

    Mukhutdinov, A. A.; Grishin, B. S.

    1994-08-01

    The physicochemical principles of the modification of crystalline chemical additives to elastomeric compositions are examined. A classification of various types of modifications based on scientific principles is given. The modifications are subdivided into physical and physicochemical depending on the configuration of the molecules in the crystals, the defectiveness and dispersity of the crystalline particles, the melting points of the crystals, and the presence of necleophilic and electrophylic centres in the molecules of the components of binary and complex eutectic mixtures. The effectiveness of the modification of the chemical additives is determined by the manifestation in binary systems of these components in elastomeric compositions of physical and chemical synergism due to the occurrence of the relevant processes in such systems. A relation has been discovered between the physical and chemical phenomena accompanying the modification of the chemical additives in binary and complex eutectic mixtures, their influence on the properties of the elastomeric composition is examined, the ecological problems associated with the processing of such materials are discussed, and the relation between the structure and properties of the molecules of the additives is analysed using quantum-chemical calculations. The bibliography includes 92 references.

  14. Acute oral toxicities of wildland fire control chemicals to birds.

    PubMed

    Vyas, Nimish B; Spann, James W; Hill, Elwood F

    2009-03-01

    Wildland fire control chemicals are released into the environment by aerial and ground applications to manage rangeland, grassland, and forest fires. Acute oral 24h median lethal dosages (LD50) for three fire retardants (Fire-Trol GTS-R, Phos-Chek D-75F, and Fire-Trol LCG-R) and two Class A fire suppressant foams (Silv-Ex and Phos-Chek WD881) were estimated for northern bobwhites, Colinus virginianus, American kestrels, Falco sparverius, and red-winged blackbirds, Agelaius phoeniceus. The LD50s of all chemicals for the bobwhites and red-winged blackbirds and for kestrels dosed with Phos-Chek WD881 and Silv-Ex were above the predetermined 2000mg chemical/kg body mass regulatory limit criteria for acute oral toxicity. The LD50s were not quantifiable for kestrels dosed with Fire-Trol GTS-R, Phos-Chek D-75F, and Fire-Trol LCG-R because of the number of birds which regurgitated the dosage. These chemicals appear to be of comparatively low order of acute oral toxicity to the avian species tested.

  15. Acute oral toxicities of wildland fire control chemicals to birds

    USGS Publications Warehouse

    Vyas, N.B.; Spann, J.W.; Hill, E.F.

    2009-01-01

    Wildland fire control chemicals are released into the environment by aerial and ground applications to manage rangeland, grassland, and forest fires. Acute oral 24 h median lethal dosages (LD50) for three fire retardants (Fire-Trol GTS-R?, Phos-Chek D-75F?, and Fire-Trol LCG-R?) and two Class A fire suppressant foams (Silv-Ex? and Phos-Chek WD881?) were estimated for northern bobwhites, Colinus virginianus, American kestrels, Falco sparverius, and red-winged blackbirds, Agelaius phoeniceus. The LD50s of all chemicals for the bobwhites and red-winged blackbirds and for kestrels dosed with Phos-Chek WD881? and Silv-Ex? were above the predetermined 2000 mg chemical/kg body mass regulatory limit criteria for acute oral toxicity. The LD50s were not quantifiable for kestrels dosed with Fire-Trol GTS-R?, Phos-Chek D-75F?, and Fire-Trol LCG-R? because of the number of birds which regurgitated the dosage. These chemicals appear to be of comparatively low order of acute oral toxicity to the avian species tested.

  16. Combinatorial QSAR modeling of chemical toxicants tested against Tetrahymena pyriformis.

    PubMed

    Zhu, Hao; Tropsha, Alexander; Fourches, Denis; Varnek, Alexandre; Papa, Ester; Gramatica, Paola; Oberg, Tomas; Dao, Phuong; Cherkasov, Artem; Tetko, Igor V

    2008-04-01

    Selecting most rigorous quantitative structure-activity relationship (QSAR) approaches is of great importance in the development of robust and predictive models of chemical toxicity. To address this issue in a systematic way, we have formed an international virtual collaboratory consisting of six independent groups with shared interests in computational chemical toxicology. We have compiled an aqueous toxicity data set containing 983 unique compounds tested in the same laboratory over a decade against Tetrahymena pyriformis. A modeling set including 644 compounds was selected randomly from the original set and distributed to all groups that used their own QSAR tools for model development. The remaining 339 compounds in the original set (external set I) as well as 110 additional compounds (external set II) published recently by the same laboratory (after this computational study was already in progress) were used as two independent validation sets to assess the external predictive power of individual models. In total, our virtual collaboratory has developed 15 different types of QSAR models of aquatic toxicity for the training set. The internal prediction accuracy for the modeling set ranged from 0.76 to 0.93 as measured by the leave-one-out cross-validation correlation coefficient ( Q abs2). The prediction accuracy for the external validation sets I and II ranged from 0.71 to 0.85 (linear regression coefficient R absI2) and from 0.38 to 0.83 (linear regression coefficient R absII2), respectively. The use of an applicability domain threshold implemented in most models generally improved the external prediction accuracy but at the same time led to a decrease in chemical space coverage. Finally, several consensus models were developed by averaging the predicted aquatic toxicity for every compound using all 15 models, with or without taking into account their respective applicability domains. We find that consensus models afford higher prediction accuracy for the

  17. An Acetyltransferase Conferring Tolerance to Toxic Aromatic Amine Chemicals

    PubMed Central

    Martins, Marta; Rodrigues-Lima, Fernando; Dairou, Julien; Lamouri, Aazdine; Malagnac, Fabienne; Silar, Philippe; Dupret, Jean-Marie

    2009-01-01

    Aromatic amines (AA) are a major class of environmental pollutants that have been shown to have genotoxic and cytotoxic potentials toward most living organisms. Fungi are able to tolerate a diverse range of chemical compounds including certain AA and have long been used as models to understand general biological processes. Deciphering the mechanisms underlying this tolerance may improve our understanding of the adaptation of organisms to stressful environments and pave the way for novel pharmaceutical and/or biotechnological applications. We have identified and characterized two arylamine N-acetyltransferase (NAT) enzymes (PaNAT1 and PaNAT2) from the model fungus Podospora anserina that acetylate a wide range of AA. Targeted gene disruption experiments revealed that PaNAT2 was required for the growth and survival of the fungus in the presence of toxic AA. Functional studies using the knock-out strains and chemically acetylated AA indicated that tolerance of P. anserina to toxic AA was due to the N-acetylation of these chemicals by PaNAT2. Moreover, we provide proof-of-concept remediation experiments where P. anserina, through its PaNAT2 enzyme, is able to detoxify the highly toxic pesticide residue 3,4-dichloroaniline in experimentally contaminated soil samples. Overall, our data show that a single xenobiotic-metabolizing enzyme can mediate tolerance to a major class of pollutants in a eukaryotic species. These findings expand the understanding of the role of xenobiotic-metabolizing enzyme and in particular of NATs in the adaptation of organisms to their chemical environment and provide a basis for new systems for the bioremediation of contaminated soils. PMID:19416981

  18. Toxicity and chemical analyses of airport runoff waters in Poland.

    PubMed

    Sulej, Anna Maria; Polkowska, Zaneta; Wolska, Lidia; Cieszynska, Monika; Namieśnik, Jacek

    2014-05-01

    The aim of this study was to assess the ecotoxicological effects of various compounds in complex airport effluents using a chemical and ecotoxicological integrated strategy. The present work deals with the determination of sum of PCBs, PAHs, pesticides, cations, anions, phenols, anionic, cationic, non-ionic detergents, formaldehyde and metals--as well as TOC and conductivity--in runoff water samples collected from 2009 to 2011 at several locations on two Polish international airports. Two microbiotests (Vibrio fischeri bacteria and the crustacean Thamnocephalus platyurus) have been used to determine the ecotoxicity of airport runoff waters. The levels of many compounds exceeded several or even several tens of times the maximum permissible levels. Analysis of the obtained data shows that samples that displayed maximum toxicity towards the bioindicators Vibrio fischeri were not toxic towards Thamnocephalus platyurus. Levels of toxicity towards T. platyurus are strongly correlated with pollutants that originate from the technological operations related to the maintenance of airport infrastructure. The integrated (chemical-ecotoxicological) approach to environmental contamination assessment in and around airports yields extensive information on the quality of the environment. These methodologies can be then used as tools for tracking the environmental fate of these compounds and for assessing the environmental effect of airports. Subsequently, these data will provide a basis for airport infrastructure management. PMID:24668023

  19. Toxicity and chemical analyses of airport runoff waters in Poland.

    PubMed

    Sulej, Anna Maria; Polkowska, Zaneta; Wolska, Lidia; Cieszynska, Monika; Namieśnik, Jacek

    2014-05-01

    The aim of this study was to assess the ecotoxicological effects of various compounds in complex airport effluents using a chemical and ecotoxicological integrated strategy. The present work deals with the determination of sum of PCBs, PAHs, pesticides, cations, anions, phenols, anionic, cationic, non-ionic detergents, formaldehyde and metals--as well as TOC and conductivity--in runoff water samples collected from 2009 to 2011 at several locations on two Polish international airports. Two microbiotests (Vibrio fischeri bacteria and the crustacean Thamnocephalus platyurus) have been used to determine the ecotoxicity of airport runoff waters. The levels of many compounds exceeded several or even several tens of times the maximum permissible levels. Analysis of the obtained data shows that samples that displayed maximum toxicity towards the bioindicators Vibrio fischeri were not toxic towards Thamnocephalus platyurus. Levels of toxicity towards T. platyurus are strongly correlated with pollutants that originate from the technological operations related to the maintenance of airport infrastructure. The integrated (chemical-ecotoxicological) approach to environmental contamination assessment in and around airports yields extensive information on the quality of the environment. These methodologies can be then used as tools for tracking the environmental fate of these compounds and for assessing the environmental effect of airports. Subsequently, these data will provide a basis for airport infrastructure management.

  20. Short-term toxicity of nine industrial chemicals

    SciTech Connect

    Komsta, E.; Secours, V.E.; Chu, I.; Morris, R.; Harrison, J.; Baranowski, E.; Villeneuve, D.C. ); Valli, V.E. )

    1989-07-01

    There are a number of industrial chemicals currently used in Canada in sufficiently large quantities that warrant a careful environmental and human health hazard assessment by the regulatory agencies. A review of the existing toxicity data for these chemicals indicated that most of the studies were inadequate due to study design, small group size, inadequate procedures or insufficient parameters being monitored. In order to determine if further studies were warranted it was decided to screen 9 of these chemicals in a short-term study using male and female rats. The chemicals were chosen based on considerations such as quantity, availability of toxicological data, chemical and structural properties and commercial availability. The chemicals selected were: tri(butoxyethyl) phosphate, dimethylol urea, 2-butyne-1,4-diol, triallyl-s-triazine-trione, cyclohexanone oxime, p-toluene sulphonhydrazide, 2-nitroaniline, propargyl alcohol and 5-methyl-1H-benzotriazole. The assay consisted of a 14-day oral dosing regime followed by a comprehensive evaluation of biochemical, hematological and histophathological changes.

  1. Toxic industrial chemicals and chemical weapons: exposure, identification, and management by syndrome.

    PubMed

    Tomassoni, Anthony J; French, Robert N E; Walter, Frank G

    2015-02-01

    Toxidromes aid emergency care providers in the context of the patient presenting with suspected poisoning, unexplained altered mental status, unknown hazardous materials or chemical weapons exposure, or the unknown overdose. The ability to capture an adequate chemical exposure history and to recognize toxidromes may reduce dependence on laboratory tests, speed time to delivery of specific antidote therapy, and improve selection of supportive care practices tailored to the etiologic agent. This article highlights elements of the exposure history and presents selected toxidromes that may be caused by toxic industrial chemicals and chemical weapons. Specific antidotes for toxidromes and points regarding their use, and special supportive measures, are presented.

  2. Passive dosing of polycyclic aromatic hydrocarbon (PAH) mixtures to terrestrial springtails: linking mixture toxicity to chemical activities, equilibrium lipid concentrations, and toxic units.

    PubMed

    Schmidt, Stine N; Holmstrup, Martin; Smith, Kilian E C; Mayer, Philipp

    2013-07-01

    A 7-day mixture toxicity experiment with the terrestrial springtail Folsomia candida was conducted, and the effects were linked to three different mixture exposure parameters. Passive dosing from silicone was applied to tightly control exposure levels and compositions of 12 mixture treatments, containing the polycyclic aromatic hydrocarbons (PAHs) naphthalene, phenanthrene, and pyrene. Springtail lethality was then linked to sum chemical activities (∑a), sum equilibrium lipid concentrations (∑C(lipid eq.)), and sum toxic units (∑TU). In each case, the effects of all 12 mixture treatments could be fitted to one sigmoidal exposure-response relationship. The effective lethal chemical activity (La50) of 0.027 was well within the expected range for baseline toxicity of 0.01-0.1. Linking the effects to the lipid-based exposure parameter yielded an effective lethal concentration (LC(lipid eq 50)) of 133 mmol kg(-1) lipid in good correspondence with the lethal membrane burden for baseline toxicity (40-160 mmol kg(-1) lipid). Finally, the effective lethal toxic unit (LTU50) of 1.20 was rather close to the expected value of 1. Altogether, passive dosing provided tightly controlled mixture exposure in terms of both level and composition, while ∑a, ∑C(lipid eq.), and ∑TU allowed baseline toxicity to be linked to mixture exposure. PMID:23473585

  3. Passive dosing of polycyclic aromatic hydrocarbon (PAH) mixtures to terrestrial springtails: linking mixture toxicity to chemical activities, equilibrium lipid concentrations, and toxic units.

    PubMed

    Schmidt, Stine N; Holmstrup, Martin; Smith, Kilian E C; Mayer, Philipp

    2013-07-01

    A 7-day mixture toxicity experiment with the terrestrial springtail Folsomia candida was conducted, and the effects were linked to three different mixture exposure parameters. Passive dosing from silicone was applied to tightly control exposure levels and compositions of 12 mixture treatments, containing the polycyclic aromatic hydrocarbons (PAHs) naphthalene, phenanthrene, and pyrene. Springtail lethality was then linked to sum chemical activities (∑a), sum equilibrium lipid concentrations (∑C(lipid eq.)), and sum toxic units (∑TU). In each case, the effects of all 12 mixture treatments could be fitted to one sigmoidal exposure-response relationship. The effective lethal chemical activity (La50) of 0.027 was well within the expected range for baseline toxicity of 0.01-0.1. Linking the effects to the lipid-based exposure parameter yielded an effective lethal concentration (LC(lipid eq 50)) of 133 mmol kg(-1) lipid in good correspondence with the lethal membrane burden for baseline toxicity (40-160 mmol kg(-1) lipid). Finally, the effective lethal toxic unit (LTU50) of 1.20 was rather close to the expected value of 1. Altogether, passive dosing provided tightly controlled mixture exposure in terms of both level and composition, while ∑a, ∑C(lipid eq.), and ∑TU allowed baseline toxicity to be linked to mixture exposure.

  4. Evaluation of Chemical Warfare Agent Percutaneous Vapor Toxicity: Derivation of Toxicity Guidelines for Assessing Chemical Protective Ensembles.

    SciTech Connect

    Watson, A.P.

    2003-07-24

    Percutaneous vapor toxicity guidelines are provided for assessment and selection of chemical protective ensembles (CPEs) to be used by civilian and military first responders operating in a chemical warfare agent vapor environment. The agents evaluated include the G-series and VX nerve agents, the vesicant sulfur mustard (agent HD) and, to a lesser extent, the vesicant Lewisite (agent L). The focus of this evaluation is percutaneous vapor permeation of CPEs and the resulting skin absorption, as inhalation and ocular exposures are assumed to be largely eliminated through use of SCBA and full-face protective masks. Selection of appropriately protective CPE designs and materials incorporates a variety of test parameters to ensure operability, practicality, and adequacy. One aspect of adequacy assessment should be based on systems tests, which focus on effective protection of the most vulnerable body regions (e.g., the groin area), as identified in this analysis. The toxicity range of agent-specific cumulative exposures (Cts) derived in this analysis can be used as decision guidelines for CPE acceptance, in conjunction with weighting consideration towards more susceptible body regions. This toxicity range is bounded by the percutaneous vapor estimated minimal effect (EME{sub pv}) Ct (as the lower end) and the 1% population threshold effect (ECt{sub 01}) estimate. Assumptions of exposure duration used in CPE certification should consider that each agent-specific percutaneous vapor cumulative exposure Ct for a given endpoint is a constant for exposure durations between 30 min and 2 hours.

  5. Impact of oil on groundwater chemical composition

    NASA Astrophysics Data System (ADS)

    Brakorenko, N. N.

    2015-11-01

    The objective of the paper is to characterize the chemical composition of groundwater samples from the monitoring wells drilled in the petrol station areas within the vicinity of Tomsk. The level of contamination has increased since many macro - and microcomponent concentrations (such as petroleum products, chlorine, sulphates, carbon dioxide and lead, etc.) in groundwater samples of the present study is higher than that in previous period samples.

  6. 40 CFR 372.22 - Covered facilities for toxic chemical release reporting.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 28 2011-07-01 2011-07-01 false Covered facilities for toxic chemical... (CONTINUED) SUPERFUND, EMERGENCY PLANNING, AND COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Reporting Requirements § 372.22 Covered facilities for toxic...

  7. 40 CFR 372.22 - Covered facilities for toxic chemical release reporting.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 29 2012-07-01 2012-07-01 false Covered facilities for toxic chemical... (CONTINUED) SUPERFUND, EMERGENCY PLANNING, AND COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Reporting Requirements § 372.22 Covered facilities for toxic...

  8. 40 CFR 372.22 - Covered facilities for toxic chemical release reporting.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 28 2014-07-01 2014-07-01 false Covered facilities for toxic chemical... (CONTINUED) SUPERFUND, EMERGENCY PLANNING, AND COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Reporting Requirements § 372.22 Covered facilities for toxic...

  9. 40 CFR 372.22 - Covered facilities for toxic chemical release reporting.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 29 2013-07-01 2013-07-01 false Covered facilities for toxic chemical... (CONTINUED) SUPERFUND, EMERGENCY PLANNING, AND COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Reporting Requirements § 372.22 Covered facilities for toxic...

  10. Chemical composition of new Acapulcoites and Lodranites

    NASA Astrophysics Data System (ADS)

    Zipfel, J.; Palme, H.

    1993-03-01

    The bulk compositions of two Antarctic Lodranites, MAC 88177 and FRO 90011, and two Acapulcoites, ALH 81261 and Monument Draw, were determined with instrumental neutron activation analysis. Acapulcoites have essentially chondritic major and trace element abundances but achondritic texture. They consist of entirely recrystallized, fine grained mineral assemblages. Chondrules are extremely rare; one relict radiating pyroxene chondrule was described in Monument Draw (MD). The coarse grained Lodranites also have achondritic textures, but they are different compositionally with depletions in Al, Na, and incompatible elements probably a result of separation of partial, feldspar-rich melt. MAC 88177 is significantly more depleted in incompatible elements than FRO 90011 suggesting a higher degree of partial melting for the MAC-Lodranite. The chemical data support a genetic relationship between Lodranites and Acapulcoites inferred earlier from oxygen isotopes, petrology, and mineral composition.

  11. Migration and Retardation of Chemical Toxic Components from Radioactive Waste - Hydrochemical Aspects

    SciTech Connect

    Jedinakova-Krizova, V.; Hanslik, E.

    2003-02-24

    A systematic analysis of nuclear power plant (NPP) operation and radioactive wastes disposal (near-surface disposal and geologic disposal) in underground repositories has provided the basis for a comparison between the radiotoxicity and chemotoxicity as part of an EIA (environmental impact assessment) procedure. This contribution summarizes the hydrochemical mechanisms of transport and retardation processes, chemistry and migration behavior of radionuclides and chemical toxics in natural sorbents, especially bentonites. The effect of solubility and dissolution reactions, diffusion and sorption/desorption, complexation and variations in the aqueous phase composition, pH-value and oxidation-reduction properties and other phenomena affecting distribution coefficients (Kd values) is discussed.

  12. Acute toxicity of fire-control chemicals, nitrogenous chemicals, and surfactants to rainbow trout

    USGS Publications Warehouse

    Buhl, Kevin J.; Hamilton, Steven J.

    2000-01-01

    Laboratory studies were conducted to determine the acute toxicity of three ammonia-based fire retardants (Fire-Trol LCA-F, Fire-Trol LCM-R, and Phos-Chek 259F), five surfactant-based fire-suppressant foams (FireFoam 103B, FireFoam 104, Fire Quench, ForExpan S, and Pyrocap B-136), three nitrogenous chemicals (ammonia, nitrate, and nitrite), and two anionic surfactants (linear alkylbenzene sulfonate [LAS] and sodium dodecyl sulfate [SDS]) to juvenile rainbow trout Oncorhynchus mykiss in soft water. The descending rank order of toxicity (96-h concentration lethal to 50% of test organisms [96-h LC50]) for the fire retardants was as follows: Phos-Chek 259F (168 mg/L) > Fire-Trol LCA-F (942 mg/L) = Fire-Trol LCM-R (1,141 mg/L). The descending rank order of toxicity for the foams was as follows: FireFoam 103B (12.2 mg/L) = FireFoam 104 (13.0 mg/L) > ForExpan S (21.8 mg/L) > Fire Quench (39.0 mg/L) > Pyrocap B-136 [156 mg/L). Except for Pyrocap B-136, the foams were more toxic than the fire retardants. Un-ionized ammonia (NH3; 0.125 mg/L as N) was about six times more toxic than nitrite (0.79 mg/L NO2-N) and about 13,300 times more toxic than nitrate (1,658 mg/L NO3-N). Linear alkylbenzene sulfonate (5.0 mg/L) was about five times more toxic than SDS (24.9 mg/L). Estimated total ammonia and NH3 concentrations at the 96-h LC50s of the fire retardants indicated that ammonia was the primary toxic component in these formulations. Based on estimated anionic surfactant concentrations at the 96-h LC50s of the foams and reference surfactants, LAS was intermediate in toxicity and SDS was less toxic to rainbow trout when compared with the foams. Comparisons of recommended application concentrations to the test results indicate that accidental inputs of these chemicals into streams require substantial dilutions (100-1,750-fold to reach concentrations nonlethal to rainbow trout.

  13. Multifaceted toxicity assessment of catalyst composites in transgenic zebrafish embryos.

    PubMed

    Jang, Gun Hyuk; Lee, Keon Yong; Choi, Jaewon; Kim, Sang Hoon; Lee, Kwan Hyi

    2016-09-01

    Recent development in the field of nanomaterials has given rise into the inquiries regarding the toxicological characteristics of the nanomaterials. While many individual nanomaterials have been screened for their toxicological effects, composites that accompany nanomaterials are not common subjects to such screening through toxicological assessment. One of the widely used composites that accompany nanomaterials is catalyst composite used to reduce air pollution, which was selected as a target composite with nanomaterials for the multifaceted toxicological assessment. As existing studies did not possess any significant data regarding such catalyst composites, this study focuses on investigating toxicological characteristics of catalyst composites from various angles in both in-vitro and in-vivo settings. Initial toxicological assessment on catalyst composites was conducted using HUVECs for cell viability assays, and subsequent in-vivo assay regarding their direct influence on living organisms was done. The zebrafish embryo and its transgenic lines were used in the in-vivo assays to obtain multifaceted analytic results. Data obtained from the in-vivo assays include blood vessel formation, mutated heart morphology, and heart functionality change. Our multifaceted toxicological assessment pointed out that chemical composites augmented with nanomaterials can too have toxicological threat as much as individual nanomaterials do and alarms us with their danger. This manuscript provides a multifaceted assessment for composites augmented with nanomaterials, of which their toxicological threats have been overlooked. PMID:27364464

  14. Multifaceted toxicity assessment of catalyst composites in transgenic zebrafish embryos.

    PubMed

    Jang, Gun Hyuk; Lee, Keon Yong; Choi, Jaewon; Kim, Sang Hoon; Lee, Kwan Hyi

    2016-09-01

    Recent development in the field of nanomaterials has given rise into the inquiries regarding the toxicological characteristics of the nanomaterials. While many individual nanomaterials have been screened for their toxicological effects, composites that accompany nanomaterials are not common subjects to such screening through toxicological assessment. One of the widely used composites that accompany nanomaterials is catalyst composite used to reduce air pollution, which was selected as a target composite with nanomaterials for the multifaceted toxicological assessment. As existing studies did not possess any significant data regarding such catalyst composites, this study focuses on investigating toxicological characteristics of catalyst composites from various angles in both in-vitro and in-vivo settings. Initial toxicological assessment on catalyst composites was conducted using HUVECs for cell viability assays, and subsequent in-vivo assay regarding their direct influence on living organisms was done. The zebrafish embryo and its transgenic lines were used in the in-vivo assays to obtain multifaceted analytic results. Data obtained from the in-vivo assays include blood vessel formation, mutated heart morphology, and heart functionality change. Our multifaceted toxicological assessment pointed out that chemical composites augmented with nanomaterials can too have toxicological threat as much as individual nanomaterials do and alarms us with their danger. This manuscript provides a multifaceted assessment for composites augmented with nanomaterials, of which their toxicological threats have been overlooked.

  15. Toxic effects of occupational and environmental chemicals on the testes

    SciTech Connect

    Sever, L.E.; Hessol, N.A.

    1983-01-01

    This paper examines evidence for effects of occupational chemicals on male reproduction. We consider primarily human data, and much of that from epidemiologic studies. We use animal studies to illustrate points, but the theme is the human experience. The approach is based on examining reproductive function as an indicator of toxic effects. Testicular structure and function is briefly discussed. We provide a brief review of relevant structure, function and hormonal control. We describe the anatomy of the testis and its histological structure. We then discuss the testis from the point of view of exocrine and endocrine function and the relationship of the testis to other endocrinological organs. This is followed by a review of methods for assessing human testicular function, including reproductive histories, sperm analysis, assessment of hormonal status, and histological studies. Although the primary focus is on human studies, we consider briefly general categories of chemicals shown to have a testicular effect in animal studies and also animal evidence of mechanisms of action associated with testicular toxicology. Specific chemicals shown to affect reproduction in the human male are reviewed and directions for future research in this area discussed.

  16. 76 FR 38169 - Toxic Substances Control Act Chemical Testing; Receipt of Test Data

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-29

    ... AGENCY Toxic Substances Control Act Chemical Testing; Receipt of Test Data AGENCY: Environmental... chemicals listed in the Toxic Substances Control Act (TSCA) section 4 test rule titled ``In Vitro Dermal Absorption Rate Testing of Certain Chemicals of Interest to the Occupational Safety and Health...

  17. [Assessment of the relationship of properties of chemical compounds and their toxicity to a unified hygienic standardization for chemicals].

    PubMed

    Trushkov, V F; Perminov, K A; Sapozhnikova, V V; Ignatova, O L

    2013-01-01

    The connection of thermodynamic properties and parameters of toxicity of chemical substances was determined. Obtained data are used for the evaluation of toxicity and hygienic rate setting of chemical compounds. The relationship between enthalpy and toxicity of chemical compounds has been established. Orthogonal planning of the experiment was carried out in the course of the investigations. Equation of unified hygienic rate setting in combined, complex, conjunct influence on the organism is presented. Prospects of determination of toxicity and methodology of unified hygienic rate setting in combined, complex, conjunct influence on the organism are presented

  18. Classification of Chemicals Based On Structured Toxicity Information

    EPA Science Inventory

    Thirty years and millions of dollars worth of pesticide registration toxicity studies, historically stored as hardcopy and scanned documents, have been digitized into highly standardized and structured toxicity data within the Toxicity Reference Database (ToxRefDB). Toxicity-bas...

  19. Environmental effects of oilfield chemicals on composite

    SciTech Connect

    Sorem, R.M.

    1998-12-31

    This paper presents a feasibility study of the effects of oilfield chemicals on composite materials. In this initial study only hydrochloric acid is considered. Initial attempts were made to test stressed specimens, but results were very poor. Subsequent testing was performed to determine how the composite material constituents reacted to the hydrochloric acid. The initial testing was performed on tubular specimens with axial and essentially hoop wound fibers of different materials with different resins. The specimens were loaded in bending to induce representative strains in the tubing. All specimens failed. The second tests consisted of only an environmental soak to determine the amount of mass uptake as well as the reduction in strength. The strength reduction results will be presented at a later time. Testing was performed on S-2 glass, carbon and Kevlar 49 as well as three different resins.

  20. Chemical composition of Texas surface waters, 1949

    USGS Publications Warehouse

    Irelan, Burdge

    1950-01-01

    This report is the fifth the a series of publications by the Texas Board of Water Engineers giving chemical analyses of the surface waters in the State of Texas. The samples for which data are given were collected between October 1, 1948 and September 30, 1949. During the water year 25 daily sampling stations were maintained by the Geological Survey. Sampled were collected less frequently during the year at many other points. Quality of water records for previous years can be found in the following reports: "Chemical Composition of Texas Surface Waters, 1938-1945," by W. W. Hastings, and J. H. Rowley; "Chemical Composition of Texas Surface Waters, 1946," by W. W. Hastings and B. Irelan; "Chemical Composition of Texas Surface Waters, 1947," by B. Irelan and J. R. Avrett; "Chemical Composition of Texas Surface Waters, 1948," by B. Irelan, D. E. Weaver, and J. R. Avrett. These reports may be obtained from the Texas Board of Water Engineers and Geological Survey at Austin, Texas. Samples for chemical analysis were collected daily at or near points on streams where gaging stations are maintained for measurement of discharge. Most of the analyses were made of 10-day composites of daily samples collected for a year at each sampling point. Three composite samples were usually prepared each month by mixing together equal quantities of daily samples collected for the 1st to the 10th, from the 11th to the 20th, and during the remainder of the month. Monthly composites were made at a few stations where variation in daily conductance was small. For some streams that are subject to sudden large changes in chemical composition, composite samples were made for shorter periods on the basis of the concentration of dissolved solids as indicated by measurement of specific conductance of the daily samples. The mean discharge for the composite period is reported in second-feet. Specific conductance values are expressed as "micromhos, K x 10 at 25° C." Silica, calcium, magnesium, sodium

  1. Globally convergent computation of chemical equilibrium composition.

    PubMed

    Patil, Sunil; Aiyer, R C; Sharma, K C

    2008-05-01

    We report the Newton-Raphson based globally convergent computational method for determination of chemical equilibrium composition. In the computation of chemical equilibrium composition, an appearance of nonpositive value of number of moles of any component leads to discrepancy. The process of conditional backtracking and adaptive set of refining factors for Newton-Raphson steps are employed to resolve the problem. The mathematical formulation proposed by Heuze et al. (J Chem Phys 1985, 83, 4734) has been solved using proposed computational method, instead of empirical iterative formulation, as proposed by them. Results for the same numerical example, used by Heuze et al. (J Chem Phys 1985, 83, 4734) and White et al. (J Chem Phys 1958, 28, 751) are presented in addition to decomposition of Cyclotrimethylenetrinitramine for fixed temperature and pressure. It is observed that the proposed method is efficient and globally convergent. An even noteworthy finding is that the set of refining factors can be chosen from the range 0.1 to eta, where eta may be greater than one depending on how smoothly system of nonlinear equations is dependant on corresponding variable. Related analysis and results are discussed.

  2. Cometary Coma Chemical Composition (C4) Mission

    NASA Technical Reports Server (NTRS)

    Carle, Glenn C.; Clark, Benton C.; Knocke, Philip C.; OHara, Bonnie J.; Adams, Larry; Niemann, Hasso B.; Alexander, Merle; Veverka, Joseph; Goldstein, Raymond; Huebner, Walter; Morrison, David (Technical Monitor)

    1994-01-01

    Cometary exploration remains of great importance to virtually all of space science. Because comets are presumed to be remnants of the early solar nebula, they are expected to provide fundamental knowledge as to the origin and development of the solar system as well as to be key to understanding of the source of volatiles and even life itself in the inner solar system. Clearly the time for a detailed study of the composition of these apparent messages from the past has come. A comet rendezvous mission, the Cometary Coma Chemical Composition (C4) Mission, is now being studied as a candidate for the new Discovery program. This mission is a highly-focussed and usefully-limited subset of the Cometary Rendezvous Asteroid Flyby (CRAF) Mission. The C4 mission will concentrate on measurements that will produce an understanding of the composition and physical makeup of a cometary nucleus. The core science goals of the C4 mission are 1) to determine the chemical, elemental, and isotopic composition of a cometary nucleus and 2) to characterize the chemical and isotopic nature of its atmosphere. A related goal is to obtain temporal information about the development of the cometary coma as a function of time and orbital position. The four short-period comets -- Tempel 1, Tempel 2, Churyumov-Gerasimenko, and Wirtanen -which all appear to have acceptable dust production rates, were identified as candidate targets. Mission opportunities have been identified beginning as early as 1998. Tempel I with a launch in 1999, however, remains the baseline comet for studies of and planning the C4 mission. The C4 mission incorporates two science instruments and two engineering instruments in the payload to obtain the desired measurements. The science instruments include an advanced version of the Cometary Ice and Dust Experiment (CIDEX), a mini-CIDEX with a sample collection system, an X-ray Fluorescence Spectrometer and a Pyrolysis-Gas Chromatograph, and a simplified version of the Neutral

  3. Low-toxic and safe nanomaterials by surface-chemical design, carbon nanotubes, fullerenes, metallofullerenes, and graphenes.

    PubMed

    Yan, Liang; Zhao, Feng; Li, Shoujian; Hu, Zhongbo; Zhao, Yuliang

    2011-02-01

    The toxicity grade for a bulk material can be approximately determined by three factors (chemical composition, dose, and exposure route). However, for a nanomaterial it depends on more than ten factors. Interestingly, some nano-factors (like huge surface adsorbability, small size, etc.) that endow nanomaterials with new biomedical functions are also potential causes leading to toxicity or damage to the living organism. Is it possible to create safe nanomaterials if such a number of complicated factors need to be regulated? We herein try to find answers to this important question. We first discuss chemical processes that are applicable for nanosurface modifications, in order to improve biocompatibility, regulate ADME, and reduce the toxicity of carbon nanomaterials (carbon nanotubes, fullerenes, metallofullerenes, and graphenes). Then the biological/toxicological effects of surface-modified and unmodified carbon nanomaterials are comparatively discussed from two aspects: the lowered toxic responses or the enhanced biomedical functions. We summarize the eight biggest challenges in creating low-toxicity and safer nanomaterials and some significant topics of future research needs: to find out safer nanofactors; to establish controllable surface modifications and simpler chemistries for low-toxic nanomaterials; to explore the nanotoxicity mechanisms; to justify the validity of current toxicological theories in nanotoxicology; to create standardized nanomaterials for toxicity tests; to build theoretical models for cellular and molecular interactions of nanoparticles; and to establish systematical knowledge frameworks for nanotoxicology.

  4. Low-toxic and safe nanomaterials by surface-chemical design, carbon nanotubes, fullerenes, metallofullerenes, and graphenes

    NASA Astrophysics Data System (ADS)

    YanEqual Contribution, Liang; Zhao, Feng; Li, Shoujian; Hu, Zhongbo; Zhao, Yuliang

    2011-02-01

    The toxicity grade for a bulk material can be approximately determined by three factors (chemical composition, dose, and exposure route). However, for a nanomaterial it depends on more than ten factors. Interestingly, some nano-factors (like huge surface adsorbability, small size, etc.) that endow nanomaterials with new biomedical functions are also potential causes leading to toxicity or damage to the living organism. Is it possible to create safe nanomaterials if such a number of complicated factors need to be regulated? We herein try to find answers to this important question. We first discuss chemical processes that are applicable for nanosurface modifications, in order to improve biocompatibility, regulate ADME, and reduce the toxicity of carbon nanomaterials (carbon nanotubes, fullerenes, metallofullerenes, and graphenes). Then the biological/toxicological effects of surface-modified and unmodified carbon nanomaterials are comparatively discussed from two aspects: the lowered toxic responses or the enhanced biomedical functions. We summarize the eight biggest challenges in creating low-toxicity and safer nanomaterials and some significant topics of future research needs: to find out safer nanofactors; to establish controllable surface modifications and simpler chemistries for low-toxic nanomaterials; to explore the nanotoxicity mechanisms; to justify the validity of current toxicological theories in nanotoxicology; to create standardized nanomaterials for toxicity tests; to build theoretical models for cellular and molecular interactions of nanoparticles; and to establish systematical knowledge frameworks for nanotoxicology.

  5. Integration of Dosimetry, Exposure and High-Throughput Screening Data in Chemical Toxicity Assessment

    EPA Science Inventory

    High-throughput in vitro toxicity screening can provide an efficient way to identify potential biological targets for chemicals. However, relying on nominal assay concentrations may misrepresent potential in vivo effects of these chemicals due to differences in bioavailability, c...

  6. STRUCTURE-ACTIVITY RELATIONSHIP STUIDES AND THEIR ROLE IN PREDICTING AND INVESTIGATING CHEMICAL TOXICITY

    EPA Science Inventory

    Structure-Activity Relationship Studies and their Role in Predicting and Investigating Chemical Toxicity

    Structure-activity relationships (SAR) represent attempts to generalize chemical information relative to biological activity for the twin purposes of generating insigh...

  7. Chemical Composition and Photometry of BE Lyncis

    NASA Astrophysics Data System (ADS)

    Kim, Chulhee; Yushchenko, A. V.; Kim, S.-L.; Jeon, Y.-B.; Kim, Chun-Hwey

    2012-05-01

    High-resolution spectroscopic observation was carried out to find the chemical composition of BE Lyn. The abundances of 25 chemical elements from carbon to neodymium were found. The deficiency of iron appeared to be equal to Δ log N(Fe) = -0.26 ± 0.08 with respect to the solar metallicity, and the abundances of other elements were mainly undersolar. Only nitrogen, sodium, aluminum, and sulfur showed overabundances near 0.2-0.3 dex. The abundance pattern showed no clear signs of accretion or mass transfer events. It is not possible to exclude the classification of BE Lyn as a SX Phe-type star with slightly undersolar abundances of chemical elements. In addition, new differential time-series observations of BE Lyn were secured using V filters, and seven new times of light maximum were identified. We collected 162 times of light maximum from the literature, unpublished data, and an open database, and we proceeded to investigate the pulsational properties of BE Lyn. All five harmonic frequencies were identified using the Fourier decomposition method.

  8. In silico assessment of the acute toxicity of chemicals: recent advances and new model for multitasking prediction of toxic effect.

    PubMed

    Kleandrova, Valeria V; Luan, Feng; Speck-Planche, Alejandro; Cordeiro, M Natália D S

    2015-01-01

    The assessment of acute toxicity is one of the most important stages to ensure the safety of chemicals with potential applications in pharmaceutical sciences, biomedical research, or any other industrial branch. A huge and indiscriminate number of toxicity assays have been carried out on laboratory animals. In this sense, computational approaches involving models based on quantitative-structure activity/toxicity relationships (QSAR/QSTR) can help to rationalize time and financial costs. Here, we discuss the most significant advances in the last 6 years focused on the use of QSAR/QSTR models to predict acute toxicity of drugs/chemicals in laboratory animals, employing large and heterogeneous datasets. The advantages and drawbacks of the different QSAR/QSTR models are analyzed. As a contribution to the field, we introduce the first multitasking (mtk) QSTR model for simultaneous prediction of acute toxicity of compounds by considering different routes of administration, diverse breeds of laboratory animals, and the reliability of the experimental conditions. The mtk-QSTR model was based on artificial neural networks (ANN), allowing the classification of compounds as toxic or non-toxic. This model correctly classified more than 94% of the 1646 cases present in the whole dataset, and its applicability was demonstrated by performing predictions of different chemicals such as drugs, dietary supplements, and molecules which could serve as nanocarriers for drug delivery. The predictions given by the mtk-QSTR model are in very good agreement with the experimental results. PMID:25694074

  9. In silico assessment of the acute toxicity of chemicals: recent advances and new model for multitasking prediction of toxic effect.

    PubMed

    Kleandrova, Valeria V; Luan, Feng; Speck-Planche, Alejandro; Cordeiro, M Natália D S

    2015-01-01

    The assessment of acute toxicity is one of the most important stages to ensure the safety of chemicals with potential applications in pharmaceutical sciences, biomedical research, or any other industrial branch. A huge and indiscriminate number of toxicity assays have been carried out on laboratory animals. In this sense, computational approaches involving models based on quantitative-structure activity/toxicity relationships (QSAR/QSTR) can help to rationalize time and financial costs. Here, we discuss the most significant advances in the last 6 years focused on the use of QSAR/QSTR models to predict acute toxicity of drugs/chemicals in laboratory animals, employing large and heterogeneous datasets. The advantages and drawbacks of the different QSAR/QSTR models are analyzed. As a contribution to the field, we introduce the first multitasking (mtk) QSTR model for simultaneous prediction of acute toxicity of compounds by considering different routes of administration, diverse breeds of laboratory animals, and the reliability of the experimental conditions. The mtk-QSTR model was based on artificial neural networks (ANN), allowing the classification of compounds as toxic or non-toxic. This model correctly classified more than 94% of the 1646 cases present in the whole dataset, and its applicability was demonstrated by performing predictions of different chemicals such as drugs, dietary supplements, and molecules which could serve as nanocarriers for drug delivery. The predictions given by the mtk-QSTR model are in very good agreement with the experimental results.

  10. Chemical composition of selected edible nut seeds.

    PubMed

    Venkatachalam, Mahesh; Sathe, Shridhar K

    2006-06-28

    Commercially important edible nut seeds were analyzed for chemical composition and moisture sorption. Moisture (1.47-9.51%), protein (7.50-21.56%), lipid (42.88-66.71%), ash (1.16-3.28%), total soluble sugars (0.55-3.96%), tannins (0.01-0.88%), and phytate (0.15-0.35%) contents varied considerably. Regardless of the seed type, lipids were mainly composed of mono- and polyunsaturated fatty acids (>75% of the total lipids). Fatty acid composition analysis indicated that oleic acid (C18:1) was the main constituent of monounsaturated lipids in all seed samples. With the exception of macadamia, linoleic acid (C18:2) was the major polyunsaturated fatty acid. In the case of walnuts, in addition to linoleic acid (59.79%) linolenic acid (C18:3) also significantly contributed toward the total polyunsaturated lipids. Amino acid composition analyses indicated lysine (Brazil nut, cashew nut, hazelnut, pine nut, and walnut), sulfur amino acids methionine and cysteine (almond), tryptophan (macadamia, pecan), and threonine (peanut) to be the first limiting amino acid as compared to human (2-5 year old) amino acid requirements. The amino acid composition of the seeds was characterized by the dominance of hydrophobic (range = 37.16-44.54%) and acidic (27.95-33.17%) amino acids followed by basic (16.16-21.17%) and hydrophilic (8.48-11.74%) amino acids. Trypsin inhibitory activity, hemagglutinating activity, and proteolytic activity were not detected in the nut seed samples analyzed. Sorption isotherms (Aw range = 0.08-0.97) indicated a narrow range for monolayer water content (11-29 mg/g of dry matter). No visible mold growth was evident on any of the samples stored at Aw < 0.53 and 25 degrees C for 6 months.

  11. Chemical composition of selected edible nut seeds.

    PubMed

    Venkatachalam, Mahesh; Sathe, Shridhar K

    2006-06-28

    Commercially important edible nut seeds were analyzed for chemical composition and moisture sorption. Moisture (1.47-9.51%), protein (7.50-21.56%), lipid (42.88-66.71%), ash (1.16-3.28%), total soluble sugars (0.55-3.96%), tannins (0.01-0.88%), and phytate (0.15-0.35%) contents varied considerably. Regardless of the seed type, lipids were mainly composed of mono- and polyunsaturated fatty acids (>75% of the total lipids). Fatty acid composition analysis indicated that oleic acid (C18:1) was the main constituent of monounsaturated lipids in all seed samples. With the exception of macadamia, linoleic acid (C18:2) was the major polyunsaturated fatty acid. In the case of walnuts, in addition to linoleic acid (59.79%) linolenic acid (C18:3) also significantly contributed toward the total polyunsaturated lipids. Amino acid composition analyses indicated lysine (Brazil nut, cashew nut, hazelnut, pine nut, and walnut), sulfur amino acids methionine and cysteine (almond), tryptophan (macadamia, pecan), and threonine (peanut) to be the first limiting amino acid as compared to human (2-5 year old) amino acid requirements. The amino acid composition of the seeds was characterized by the dominance of hydrophobic (range = 37.16-44.54%) and acidic (27.95-33.17%) amino acids followed by basic (16.16-21.17%) and hydrophilic (8.48-11.74%) amino acids. Trypsin inhibitory activity, hemagglutinating activity, and proteolytic activity were not detected in the nut seed samples analyzed. Sorption isotherms (Aw range = 0.08-0.97) indicated a narrow range for monolayer water content (11-29 mg/g of dry matter). No visible mold growth was evident on any of the samples stored at Aw < 0.53 and 25 degrees C for 6 months. PMID:16787018

  12. Chemical and biological properties related to toxicity of heated fats.

    PubMed

    Alexander, J C

    1981-01-01

    Heating of fats brings about measurable changes in their chemical and physical characteristics. Heat is applied in processing for food manufacture, such as during hydrogenation of oils with a catalyst, and in frying for meal preparation. Partially hydrogenated products generally contain substantial quantities of geometric and positional isomers of the original unsaturated fatty acids. During deep-fat frying, when the fat is used repeatedly, oxidative and thermal effects result in the formation of many volatile and nonvolatile products, some of which are potentially toxic, depending on the level of intake. Because of concern about the types of changes that take place in fats during oxidative and thermal deterioration and the effects the derivatives could have on the consumer, many chemical and biological studies have been carried out. Experimental findings indicate that any potential danger to the consumer is relative to the severity of the overall treatment of the fat. In some studies we evaluated biological effects on rats of trans fatty acid in the diet and of concentrates of fatty acid derivatives produced in thermally oxidized fats. trans-Octadecenoic acid changed the concentrations of the phospholipid classes in the liver lipids, and interfered with conversion of the essential n - 6 series of fatty acids to higher members. Compared to oleic acid, elaidic acid was preferentially incorporated into the phospholipids instead of the triacylglycerols and was also concentrated in the lipoprotein fractions. Administration of non-urea-adductable concentrates from thermally oxidized fats produced cellular damage in hearts, livers, and kidneys of the animals. Since even practical processing and frying conditions can produce some nutritionally undesirable products, a concerted effort should be made to minimize substantial accumulation of these in our dietary fats.

  13. Toxicity testing of organic chemicals in groundwater polluted with landfill leachate

    SciTech Connect

    Baun, A.; Kloeft, L.; Bjerg, P.L.; Nyholm, N.

    1999-09-01

    A method for assessment of toxicity of nonvolatile organic chemicals contaminants in groundwater polluted with landfill leachate has been evaluated. The biotests utilized were composed of an algal growth inhibition test (Selenastrum capricornutum), a daphnia immobilization test (Daphnia magna), and a bacterial genotoxicity test (umuC, Salmonella typhimurium). The feasibility of the selected biotests was investigated for a series of groundwater samples collected along pollution gradients downstreams of two landfills in Jutland, Denmark. Two different approaches were used, direct toxicity testing of whole groundwater samples, and toxicity testing of concentrates obtained by solid-phase extraction. Direct testing of whole groundwater samples produced toxic responses, but the complex sample matrix masked the toxicity of the organic chemical contaminants of interest. Solid-phase extraction was used successfully as an on-site method that eliminated ion toxicity and produced biotest responses that reflected the toxicity of the nonvolatile organic chemical contaminants in the groundwater.

  14. Non-toxic invert analog glass compositions of high modulus

    NASA Technical Reports Server (NTRS)

    Bacon, J. F. (Inventor)

    1974-01-01

    Glass compositions having a Young's modulus of at least 15 million psi are described. They and a specific modulus of at least 110 million inches consist essentially of, in mols, 15 to 40% SiO2, 6 to 15% Li2O, 24 to 45% of at least two bivalent oxides selected from the group consisting of Ca, NzO, MgO and CuO; 13 to 39% of at least two trivalent oxides selected from the group consisting of Al2O3, Fe2O3, B2O3, La2O3, and Y2O3 and up to 15% of one or more tetravelent oxides selected from the group consisting of ZrO2, TiO2 and CeO2. The high modulus, low density glass compositions contain no toxic elements. The composition, glass density, Young's modulus, and specific modulus for 28 representative glasses are presented. The fiber modulus of five glasses are given.

  15. Screening for Chemical Toxicity Using Cryopreserved Precision Cut Lung Slices.

    PubMed

    Watson, Christa Y; Damiani, Flavia; Ram-Mohan, Sumati; Rodrigues, Sylvia; de Moura Queiroz, Priscila; Donaghey, Thomas C; Rosenblum Lichtenstein, Jamie H; Brain, Joseph D; Krishnan, Ramaswamy; Molina, Ramon M

    2016-03-01

    To assess chemical toxicity, current high throughput screening (HTS) assays rely primarily on in vitro measurements using cultured cells. Responses frequently differ from in vivo results due to the lack of physical and humoral interactions provided by the extracellular matrix, cell-cell interactions, and other molecular components of the native organ. To more accurately reproduce organ complexity in HTS, we developed an organotypic assay using the cryopreserved precision cut lung slice (PCLS) from rats and mice. Compared to the never-frozen PCLS, their frozen-thawed counterpart slices showed viability or metabolic activity that is decreased to an extent comparable to that observed in other cryopreserved cells and tissues, but shows no differences in further changes in cell viability, mitochondrial integrity, and glutathione activity in response to the model toxin zinc chloride (ZnCl2). Notably, these measurements were successfully miniaturized so as to establish HTS capacity in a 96-well plate format. Finally, PCLS responses correlated with common markers of lung injury measured in lavage fluid from rats intratracheally instilled with ZnCl2. In summary, we establish that the cryopreserved PCLS is a feasible approach for HTS investigations in predictive toxicology. PMID:26719368

  16. Discrimination of excess toxicity from narcotic effect: comparison of toxicity of class-based organic chemicals to Daphnia magna and Tetrahymena pyriformis.

    PubMed

    Zhang, Xujia; Qin, Weichao; He, Jia; Wen, Yang; Su, Limin; Sheng, Lianxi; Zhao, Yuanhui

    2013-09-01

    The discrimination of excess toxicity from narcotic effect plays a crucial role in the study of modes of toxic action for organic compounds. In this paper, the toxicity data of 758 chemicals to Daphnia magna and 993 chemicals to Tetrahymena pyriformis were used to investigate the excess toxicity. The result showed that mode of toxic action of chemicals is species dependent. The toxic ratio (TR) calculated from baseline model over the experimentally determined values showed that some classes (e.g. alkanes, alcohols, ethers, aldehydes, esters and benzenes) shared same modes of toxic action to both D. magna and T. pyriformis. However, some classes may share different modes of toxic action to T. pyriformis and D. magna (e.g. anilines and their derivatives). For the interspecies comparison, same reference threshold need to be used between species toxicity. The excess toxicity indicates that toxicity enhancement is driven by reactive or specific toxicity. However, not all the reactive compounds exhibit excess toxicity. In theory, the TR threshold should not be related with the experimental uncertainty. The experimental uncertainty only brings the difficulty for discriminating the toxic category of chemicals. The real threshold of excess toxicity which is used to identify baseline from reactive chemicals should be based on the critical concentration difference inside body, rather than critical concentration outside body (i.e. EC50 or IGC50). The experimental bioconcentration factors can be greatly different from predicted bioconcentration factors, resulting in different toxic ratios and leading to mis-classification of toxic category and outliers.

  17. Equity and Information: Information Regulation, Environmental Justice, and Risks from Toxic Chemicals

    ERIC Educational Resources Information Center

    Shapiro, Marc D.

    2005-01-01

    Decreases over time in pounds of industrial chemical emissions have led to concerns that nonminority, higher-income communities have benefited disproportionately in reductions in risk. Toxic chemical release data, modeled for toxicity and dispersion in square kilometer units across 45 states, are used to test six sets of hypotheses of potential…

  18. A FLUORESCENCE BASED ASSAY FOR DNA DAMAGE INDUCED BY TOXIC INDUSTRIAL CHEMICALS

    EPA Science Inventory

    One of the reported effects for exposure to many of the toxic industrial chemicals is DNA damage. The present study describes a simple, rapid and innovative assay to detect DNA damage resulting from exposure of surrogate DNA to toxic industrial chemicals (acrolein, allylamine, ch...

  19. A Conceptual Framework for Predicting the Toxicity of Reactive Chemicals: Modeling Soft Electrophilicity

    EPA Science Inventory

    Although the literature is replete with QSAR models developed for many toxic effects caused by reversible chemical interactions, the development of QSARs for the toxic effects of reactive chemicals lacks a consistent approach. While limitations exit, an appropriate starting-point...

  20. Toxicity Screening of the ToxCast Chemical Library Using a Zebrafish Developmental Assay

    EPA Science Inventory

    As part of the chemical screening and prioritization research program of the U.S. Environmental Protection Agency, the toxicity of the 320 ToxCast™ Phase I chemicals were assessed using a vertebrate screen of developmental toxicity. Zebrafish embryos/larvae (Danio rerio) were exp...

  1. COMPUTER SUPPORT SYSTEMS FOR ESTIMATING CHEMICAL TOXICITY: PRESENT CAPABILITIES AND FUTURE TRENDS

    EPA Science Inventory

    Computer Support Systems for Estimating Chemical Toxicity: Present Capabilities and Future Trends

    A wide variety of computer-based artificial intelligence (AI) and decision support systems exist currently to aid in the assessment of toxicity for environmental chemicals. T...

  2. Applications and toxicity of graphene family nanomaterials and their composites.

    PubMed

    Singh, Zorawar

    2016-01-01

    Graphene has attracted much attention of scientific community due to its enormous potential in different fields, including medical sciences, agriculture, food safety, cancer research, and tissue engineering. The potential for widespread human exposure raises safety concerns about graphene and its derivatives, referred to as graphene family nanomaterials (GFNs). Due to their unique chemical and physical properties, graphene and its derivatives have found important places in their respective application fields, yet they are being found to have cytotoxic and genotoxic effects too. Since the discovery of graphene, a number of researches are being conducted to find out the toxic potential of GFNs to different cell and animal models, finding their suitability for being used in new and varied innovative fields. This paper presents a systematic review of the research done on GFNs and gives an insight into the mode and action of these nanosized moieties. The paper also emphasizes on the recent and up-to-date developments in research on GFNs and their nanocomposites for their toxic effects.

  3. Applications and toxicity of graphene family nanomaterials and their composites

    PubMed Central

    Singh, Zorawar

    2016-01-01

    Graphene has attracted much attention of scientific community due to its enormous potential in different fields, including medical sciences, agriculture, food safety, cancer research, and tissue engineering. The potential for widespread human exposure raises safety concerns about graphene and its derivatives, referred to as graphene family nanomaterials (GFNs). Due to their unique chemical and physical properties, graphene and its derivatives have found important places in their respective application fields, yet they are being found to have cytotoxic and genotoxic effects too. Since the discovery of graphene, a number of researches are being conducted to find out the toxic potential of GFNs to different cell and animal models, finding their suitability for being used in new and varied innovative fields. This paper presents a systematic review of the research done on GFNs and gives an insight into the mode and action of these nanosized moieties. The paper also emphasizes on the recent and up-to-date developments in research on GFNs and their nanocomposites for their toxic effects. PMID:27051278

  4. Applications and toxicity of graphene family nanomaterials and their composites.

    PubMed

    Singh, Zorawar

    2016-01-01

    Graphene has attracted much attention of scientific community due to its enormous potential in different fields, including medical sciences, agriculture, food safety, cancer research, and tissue engineering. The potential for widespread human exposure raises safety concerns about graphene and its derivatives, referred to as graphene family nanomaterials (GFNs). Due to their unique chemical and physical properties, graphene and its derivatives have found important places in their respective application fields, yet they are being found to have cytotoxic and genotoxic effects too. Since the discovery of graphene, a number of researches are being conducted to find out the toxic potential of GFNs to different cell and animal models, finding their suitability for being used in new and varied innovative fields. This paper presents a systematic review of the research done on GFNs and gives an insight into the mode and action of these nanosized moieties. The paper also emphasizes on the recent and up-to-date developments in research on GFNs and their nanocomposites for their toxic effects. PMID:27051278

  5. Computerized in vitro test for chemical toxicity based on tetrahymena swimming patterns

    NASA Technical Reports Server (NTRS)

    Noever, David A.; Matsos, Helen C.; Cronise, Raymond J.; Looger, Loren L.; Relwani, Rachna A.; Johnson, Jacqueline U.

    1994-01-01

    An apparatus and method for rapidly determining chemical toxicity was evaluated. The toxicity monitor includes an automated scoring of how motile biological cells (Tetrahymena pyriformis) slow down or otherwise change their swimming patterns in a hostile chemical environment. The device, called the Motility Assay Apparatus (MAA) is tested for 30 second determination of chemical toxicity in 20 aqueous samples containing trace organics and salts. With equal or better detection limits, results compare favorably to in vivo animal tests of eye irritancy, in addition to agreeing for all chemicals with previous manual evaluations of single cell motility.

  6. Effects of water temperature on the toxicity of chemicals to aquatic organisms

    SciTech Connect

    Mayer, F.; Brecken-Folse, J.; Howe, G.; Linton, T.

    1995-12-31

    Water temperatures fluctuate regularly in aquatic environments, producing physiological and ecological changes in resident biota. Temperature has been recognized as a critical factor affecting the toxicity of chemicals by altering the physiological condition of the biota and the interactions between organisms and toxicants. Temperature significantly affects respiration rates, chemical absorption, and chemical detoxification and excretion. Acute toxicity of most chemicals to aquatic organisms is positively correlated with temperature; however, the toxicity of some chemicals is negatively correlated with or not affected by temperature. Regression slopes of toxicity appear consistent among species within a chemical for temperature, indicating chemical rather than biological differences in toxicity. Temperature may not affect acute toxicity per se, but does affect bioavailability and, therefore, exposure. Octanol/water partition coefficients are altered by temperature and could replace some biological testing since the partition coefficient-acute toxicity relationship has been well established. Temperature may only alter the rate of intoxication in chronic exposures no-effect concentrations do not appear to be affected by temperature; only the time required to attain the same no-effect concentration varies.

  7. Antioxidants as potential medical countermeasures for chemical warfare agents and toxic industrial chemicals.

    PubMed

    McElroy, Cameron S; Day, Brian J

    2016-01-15

    The continuing horrors of military conflicts and terrorism often involve the use of chemical warfare agents (CWAs) and toxic industrial chemicals (TICs). Many CWA and TIC exposures are difficult to treat due to the danger they pose to first responders and their rapid onset that can produce death shortly after exposure. While the specific mechanism(s) of toxicity of these agents are diverse, many are associated either directly or indirectly with increased oxidative stress in affected tissues. This has led to the exploration of various antioxidants as potential medical countermeasures for CWA/TIC exposures. Studies have been performed across a wide array of agents, model organisms, exposure systems, and antioxidants, looking at an almost equally diverse set of endpoints. Attempts at treating CWAs/TICs with antioxidants have met with mixed results, ranging from no effect to nearly complete protection. The aim of this commentary is to summarize the literature in each category for evidence of oxidative stress and antioxidant efficacy against CWAs and TICs. While there is great disparity in the data concerning methods, models, and remedies, the outlook on antioxidants as medical countermeasures for CWA/TIC management appears promising.

  8. Chemical Properties And Toxicity of Chromium(III) Nutritional Supplements

    SciTech Connect

    Levina, A.; Lay, P.A.

    2009-05-19

    The status of Cr(III) as an essential micronutrient for humans is currently under question. No functional Cr(III)-containing biomolecules have been definitively described as yet, and accumulated experience in the use of Cr(III) nutritional supplements (such as [Cr(pic){sub 3}], where pic = 2-pyridinecarboxylato) has shown no measurable benefits for nondiabetic people. Although the use of large doses of Cr(III) supplements may lead to improvements in glucose metabolism for type 2 diabetics, there is a growing concern over the possible genotoxicity of these compounds, particularly of [Cr(pic){sub 3}]. The current perspective discusses chemical transformations of Cr(III) nutritional supplements in biological media, with implications for both beneficial and toxic actions of Cr(III) complexes, which are likely to arise from the same biochemical mechanisms, dependent on concentrations of the reactive species. These species include: (1) partial hydrolysis products of Cr(III) nutritional supplements, which are capable of binding to biological macromolecules and altering their functions; and (2) highly reactive Cr(VI/V/IV) species and organic radicals, formed in reactions of Cr(III) with biological oxidants. Low concentrations of these species are likely to cause alterations in cell signaling (including enhancement of insulin signaling) through interactions with the active centers of regulatory enzymes in the cell membrane or in the cytoplasm, while higher concentrations are likely to produce genotoxic DNA lesions in the cell nucleus. These data suggest that the potential for genotoxic side-effects of Cr(III) complexes may outweigh their possible benefits as insulin enhancers, and that recommendations for their use as either nutritional supplements or antidiabetic drugs need to be reconsidered in light of these recent findings.

  9. Blister fluid composition in a pediatric patient with toxic epidermal necrolysis.

    PubMed

    Gandhi, Mona; Kowal-Vern, Areta; An, Gary; Hanumadass, Marella

    2008-01-01

    Toxic epidermal necrolysis (TEN) is a rare life-threatening disease mostly related to drug ingestion. Apoptotic keratinocytes lead to separation of the epidermis from dermis and widespread blistering of the skin. This case is a pediatric patient with a seizure disorder who developed TEN after starting carbamezepine. Blister fluid was analyzed for protein, chemical, and mineral content. The TEN blister fluid composition was similar to burn blister, except that the burn blister fluid has a 3-fold increase in albumin and protein. There was a substantial increase in lactate dehydrogenase, calcium, and magnesium in both blister fluid specimens compared with serum levels. To our knowledge, this report is the first in the literature to analyze TEN blister fluid composition and compare it to burn blister fluid.

  10. Microbial toxicity of mixtures of organic chemicals in soil medium-experimental protocol and modeling

    SciTech Connect

    Arulgnanendran, V.R.J.; Khandan, N.N.

    1995-12-31

    A laboratory procedure was developed to measure the microbial toxicity in soils using respirometric technique. The procedure was tested on 35 organic chemicals and several 8- and 10- component equitoxic mixtures. The chemicals assayed in this study were found to act jointly by simple addition. A modeling approach incorporating partitioning, sorption and Quantitative Structure Activity Relationship (QSAR) techniques was developed to estimate single chemical and mixture toxicity. This modeling approach was validated using an external testing set of data.

  11. Primary chemical and physical characterization of acute toxic components in wastewaters

    SciTech Connect

    Svenson, A.; Linlin, Z.; Kaj, L. )

    1992-10-01

    A chemical and physical primary characterization work sheet was developed based on the Microtox test, a bacterial bioluminescence system used as a rapid estimate of acute aquatic toxic effects. Measurements of the variation in light reduction upon different pretreatments provided information about the chemical and physical properties of the main toxic component(s) in test wastewater samples. This primary characterization of a wastewater sample was performed within 1 day. Tests of pure toxic chemical compounds and wastewaters with known and unknown primary toxicants are presented. Outlines to the chemical analysis and identification of toxic components may be deduced from the primary characterization. The provisional characterization may also provide information on wastewater treatment techniques.

  12. On-line chemical composition analyzer development

    SciTech Connect

    Roberts, M.J.; Garrison, A.A.; Muly, E.C.; Moore, C.F.

    1992-02-01

    The energy consumed in distillation processes in the United States represents nearly three percent of the total national energy consumption. If effective control of distillation columns can be accomplished, it has been estimated that it would result in a reduction in the national energy consumption of 0.3%. Real-time control based on mixture composition could achieve these savings. However, the major distillation processes represent diverse applications and at present there does not exist a proven on-line chemical composition sensor technology which can be used to control these diverse processes in real-time. This report presents a summary of the findings of the second phase of a three phase effort undertaken to develop an on-line real-time measurement and control system utilizing Raman spectroscopy. A prototype instrument system has been constructed utilizing a Perkin Elmer 1700 Spectrometer, a diode pumped YAG laser, two three axis positioning systems, a process sample cell land a personal computer. This system has been successfully tested using industrially supplied process samples to establish its performance. Also, continued application development was undertaken during this Phase of the program using both the spontaneous Raman and Surface-enhanced Raman modes of operation. The study was performed for the US Department of Energy, Office of Industrial Technologies, whose mission is to conduct cost-shared R D for new high-risk, high-payoff industrial energy conservation technologies. Although this document contains references to individual manufacturers and their products, the opinions expressed on the products reported do not necessarily reflect the position of the Department of Energy.

  13. Chemical compositions of large cluster IDPs

    SciTech Connect

    Flynn, G.J.; Lanzirotti, A.; Sutton, S.R.

    2006-12-06

    We performed X-ray fluorescence spectroscopy on two large cluster IDPs, which sample the IDP parent body at a mass scale two orders-of-magnitude larger than {approx}10 {micro}m IDPs, allowing proper incorporation of larger mineral grains into the bulk composition of the parent body. We previously determined that {approx}10 {micro}m interplanetary dust particles (IDPs) collected from the Earth's stratosphere are enriched in many moderately volatile elements by a factor of {approx}3 over the CI meteorites. However, these IDP measurements provide no direct constraint on the bulk chemical composition of the parent body (or parent bodies) of the IDPs. Collisions are believed to be the major mechanism for dust production by the asteroids, producing dust by surface erosion, cratering and catastrophic disruption. Hypervelocity impact experiments at {approx}5 km/sec, which is the mean collision velocity in the main belt, performed by Flynn and Durda on ordinary chondrite meteorites and the carbonaceous chondrite meteorite Allende show that the 10 {micro}m debris is dominated by matrix material while the debris larger than {approx}25 {micro}m is dominated by chondrule fragments. Thus, if the IDP parent body is similar in structure to the chondritic meteorites, it is likely that the {approx}10 {micro}m IDPs oversample the fine-grained component of the parent body. We have examined the matrix material from the few meteorites that are sufficiently fine-grained to be samples of potential IDP parent bodies. This search has, thus far, not produced a compositional and mineralogical match to either the hydrous or anhydrous IDPs. This result, coupled with our recent mapping of the element distributions, which indicates the enrichment of moderately volatile elements is not due to contamination on their surfaces, suggests the IDPs represent a new type of extraterrestrial material. Nonetheless, the meteorite fragmentation results suggest that compositional measurements on 10 {micro

  14. Chemical composition of French mimosa absolute oil.

    PubMed

    Perriot, Rodolphe; Breme, Katharina; Meierhenrich, Uwe J; Carenini, Elise; Ferrando, Georges; Baldovini, Nicolas

    2010-02-10

    Since decades mimosa (Acacia dealbata) absolute oil has been used in the flavor and perfume industry. Today, it finds an application in over 80 perfumes, and its worldwide industrial production is estimated five tons per year. Here we report on the chemical composition of French mimosa absolute oil. Straight-chain analogues from C6 to C26 with different functional groups (hydrocarbons, esters, aldehydes, diethyl acetals, alcohols, and ketones) were identified in the volatile fraction. Most of them are long-chain molecules: (Z)-heptadec-8-ene, heptadecane, nonadecane, and palmitic acid are the most abundant, and constituents such as 2-phenethyl alcohol, methyl anisate, and ethyl palmitate are present in smaller amounts. The heavier constituents were mainly triterpenoids such as lupenone and lupeol, which were identified as two of the main components. (Z)-Heptadec-8-ene, lupenone, and lupeol were quantified by GC-MS in SIM mode using external standards and represents 6%, 20%, and 7.8% (w/w) of the absolute oil. Moreover, odorant compounds were extracted by SPME and analyzed by GC-sniffing leading to the perception of 57 odorant zones, of which 37 compounds were identified by their odorant description, mass spectrum, retention index, and injection of the reference compound. PMID:20070087

  15. Chemical composition of French mimosa absolute oil.

    PubMed

    Perriot, Rodolphe; Breme, Katharina; Meierhenrich, Uwe J; Carenini, Elise; Ferrando, Georges; Baldovini, Nicolas

    2010-02-10

    Since decades mimosa (Acacia dealbata) absolute oil has been used in the flavor and perfume industry. Today, it finds an application in over 80 perfumes, and its worldwide industrial production is estimated five tons per year. Here we report on the chemical composition of French mimosa absolute oil. Straight-chain analogues from C6 to C26 with different functional groups (hydrocarbons, esters, aldehydes, diethyl acetals, alcohols, and ketones) were identified in the volatile fraction. Most of them are long-chain molecules: (Z)-heptadec-8-ene, heptadecane, nonadecane, and palmitic acid are the most abundant, and constituents such as 2-phenethyl alcohol, methyl anisate, and ethyl palmitate are present in smaller amounts. The heavier constituents were mainly triterpenoids such as lupenone and lupeol, which were identified as two of the main components. (Z)-Heptadec-8-ene, lupenone, and lupeol were quantified by GC-MS in SIM mode using external standards and represents 6%, 20%, and 7.8% (w/w) of the absolute oil. Moreover, odorant compounds were extracted by SPME and analyzed by GC-sniffing leading to the perception of 57 odorant zones, of which 37 compounds were identified by their odorant description, mass spectrum, retention index, and injection of the reference compound.

  16. TOXICOGENOMIC STUDY OF TRIAZOLE FUNGICIDES AND PERFLUOROALKYL ACIDS IN RAT LIVERS ACCURATELY CATEGORIZES CHEMICALS AND IDENTIFIES MECHANISMS OF TOXICITY

    EPA Science Inventory

    Toxicogenomic analysis of five environmental chemicals was performed to investigate the ability of genomics to predict toxicity, categorize chemicals, and elucidate mechanisms of toxicity. Three triazole antifungals (myclobutanil, propiconazole, and triadimefon) and two perfluori...

  17. 2008 Toxic Chemical Release Inventory 2008 Toxic Chemical Release Inventory Community Right-to-Know Act of 1986, Title III, Section 313

    SciTech Connect

    Ecology and Air Quality Group

    2009-10-01

    For reporting year 2008, Los Alamos National Laboratory (LANL) submitted a Form R report for lead as required under the Emergency Planning and Community Right-to- Know Act (EPCRA) Section 313. No other EPCRA Section 313 chemicals were used in 2008 above the reportable thresholds. This document was prepared to provide a description of the evaluation of EPCRA Section 313 chemical use and threshold determinations for LANL for calendar year 2008, as well as to provide background information about data included on the Form R reports. Section 313 of EPCRA specifically requires facilities to submit a Toxic Chemical Release Inventory Report (Form R) to the U.S. Environmental Protection Agency (EPA) and state agencies if the owners and operators manufacture, process, or otherwise use any of the listed toxic chemicals above listed threshold quantities. EPA compiles this data in the Toxic Release Inventory database. Form R reports for each chemical over threshold quantities must be submitted on or before July 1 each year and must cover activities that occurred at the facility during the previous year. In 1999, EPA promulgated a final rule on persistent bioaccumulative toxics (PBTs). This rule added several chemicals to the EPCRA Section 313 list of toxic chemicals and established lower reporting thresholds for these and other PBT chemicals that were already reportable. These lower thresholds became applicable in reporting year 2000. In 2001, EPA expanded the PBT rule to include a lower reporting threshold for lead and lead compounds. Facilities that manufacture, process, or otherwise use more than 100 lb of lead or lead compounds must submit a Form R.

  18. Relationships between exposure and dose in aquatic toxicity tests for organic chemicals.

    PubMed

    Mackay, Donald; McCarty, Lynn S; Arnot, Jon A

    2014-09-01

    There is continuing debate about the merits of exposure-based toxicity metrics such as median lethal concentration (LC50) versus organism-based metrics such as critical body residue (CBR) as indicators of chemical toxicity to aquatic organisms. To demonstrate relationships and differences between these 2 metrics, the authors applied a simple one-compartment toxicokinetic mass-balance model for water-exposed fish for a series of hypothetical organic chemicals exhibiting baseline narcotic toxicity. The authors also considered the influence of several toxicity-modifying factors. The results showed that the results of standard toxicity tests, such as the LC50, are strongly influenced by several modifying factors, including chemical and organism characteristics such as hydrophobicity, body size, lipid content, metabolic biotransformation, and exposure durations. Consequently, reported LC50s may not represent consistent dose surrogates and may be inappropriate for comparing the relative toxicity of chemicals. For comparisons of toxicity between chemicals, it is preferable to employ a delivered dose metric, such as the CBR. Reproducible toxicity data for a specific combination of chemical, exposure conditions, and organism can be obtained only if the extent of approach to steady state is known. Suggestions are made for revisions in test protocols, including the use of models in advance of empirical testing, to improve the efficiency and effectiveness of tests and reduce the confounding influences of toxicity-modifying factors, especially exposure duration and metabolic biotransformation. This will assist in linking empirical measurements of LC50s and CBRs, 2 different but related indicators of aquatic toxicity, and thereby improve understanding of the large existing database of aquatic toxicity test results.

  19. Computerized In Vitro Test for Chemical Toxicity Based on Tetrahymena Swimming Patterns

    NASA Technical Reports Server (NTRS)

    Noever, David A.; Matsos, Helen C.; Cronise, Raymond J.; Looger, Loren L.; Relwani, Rachna A.; Johnson, Jacqueline U.

    1994-01-01

    An apparatus and a method for rapidly determining chemical toxicity have been evaluated as an alternative to the rabbit eye initancy test (Draize). The toxicity monitor includes an automated scoring of how motile biological cells (Tetrahymena pyriformis) slow down or otherwise change their swimming patterns in a hostile chemical environment. The method, called the motility assay (MA), is tested for 30 s to determine the chemical toxicity in 20 aqueous samples containing trace organics and salts. With equal or better detection limits, results compare favorably to in vivo animal tests of eye irritancy.

  20. Toxicity of organic chemicals and their mixtures to activated sludge microorganisms

    SciTech Connect

    Hall, E.; Sun, B.; Prakash, J.; Nirmalakhandan, N.

    1996-05-01

    Toxicity of eight- and 10-component mixtures of several organic chemicals to activated sludge (A/S) microorganisms was analyzed. The joint toxic effects of the tested chemicals were found to be simply additive. The quantitative structure-activity relationship (QSAR) technique using molecular connectivity indices was used to develop single variable models to fit single chemical toxicity data. A QSAR-based approach is proposed to predict the concentrations of components in equitoxic mixtures that would jointly cause 50% inhibition of the A/S microorganisms. The validity of this predictive approach was demonstrated by comparing the predicted concentrations against those found experimentally.

  1. Investigating the Toxicity of the Aeruginosin Chlorosulfopeptides by Chemical Synthesis.

    PubMed

    Scherer, Manuel; Bezold, Dominik; Gademann, Karl

    2016-08-01

    Harmful algal blooms are becoming more prevalent all over the world, and identification and mechanism-of-action studies of the responsible toxins serve to protect ecosystems, livestock, and humans alike. In this study, the chlorosulfopeptide aeruginosin 828A, which rivals the well-known toxin microcystin LR in terms of crustacean toxicity, has been synthesized for the first time. Furthermore, three congeners with different permutations of the chloride and sulfate groups were prepared, thereby enabling toxicity studies without the risk of contamination by other natural toxins. Toxicity assays with the sensitive crustacean Thamnocephalus platyurus demonstrated that the introduction of a sulfate group leads to pronounced toxicity, and NMR spectroscopic evidence suggests that the chloride substituent modulates the conformation, which in turn might influence protease inhibition. PMID:27332048

  2. Uptake and toxicity of polycyclic aromatic hydrocarbons in terrestrial springtails--studying bioconcentration kinetics and linking toxicity to chemical activity.

    PubMed

    Schmidt, Stine Nørgaard; Smith, Kilian Eric Christopher; Holmstrup, Martin; Mayer, Philipp

    2013-02-01

    Passive dosing applies a polymer loaded with test compound(s) to establish and maintain constant exposure in laboratory experiments. Passive dosing with the silicone poly(dimethylsiloxane) was used to control exposure of the terrestrial springtail Folsomia candida to six polycyclic aromatic hydrocarbons (PAHs) in bioconcentration and toxicity experiments. Folsomia candida could move freely on the PAH-loaded silicone, resulting in exposure via air and direct contact. The bioconcentration kinetics indicated efficient uptake of naphthalene, anthracene, and pyrene through air and (near) equilibrium partitioning of these PAHs to lipids and possibly the waxy layer of the springtail cuticle. Toxicities of naphthalene, phenanthrene, and pyrene were related to chemical activity, which quantifies the energetic level and drives spontaneous processes including diffusive biouptake. Chemical activity-response relationships yielded effective lethal chemical activities (La50s) well within the expected range for baseline toxicity (0.01-0.1). Effective lethal body burdens for naphthalene and pyrene exceeded the expected range of 2 to 8 mmol kg(-1) fresh weight, which again indicated the waxy layer to be a sorbing phase. Finally, chemical activities were converted into equilibrium partitioning concentrations in lipids yielding effective lethal concentrations for naphthalene and phenanthrene in good correspondence with the lethal membrane burden for baseline toxicity (40-160 mmol kg(-1) lipid). Passive dosing was a practical approach for tightly controlling PAH exposure, which in turn provided new experimental possibilities and findings. PMID:23147567

  3. Comparative toxicity of four chemically dispersed and undispersed crude oils to rainbow trout embryos.

    PubMed

    Wu, Dongmei; Wang, Zhendi; Hollebone, Bruce; McIntosh, Stephen; King, Tom; Hodson, Peter V

    2012-04-01

    The chronic toxicity of crude oil to fish embryos depends on the chemical constituents of the test oil and on factors that control the exposure of embryos to those constituents. The partitioning of chemicals from oil to water depends on the surface area of oil exposed to water and thus on the susceptibility of oil to be dispersed into droplets. The chronic toxicity of four different crude oils to embryos of rainbow trout (Oncorhynchus mykiss) was measured by exposure to the water-accommodated fraction (WAF; no droplet formation) and to the chemically enhanced WAF (CEWAF) of each oil. When effects were compared with the amount of WAF or CEWAF added to test solutions, chemical dispersion increased toxicity dramatically, by >35 to >300-fold, with the smallest difference measured for the lightest and least viscous oil. When effects were compared with measured concentrations of oil in test solutions, there were no differences in toxicity between WAF and CEWAF treatments, indicating that chemical dispersion promoted droplet formation and the partitioning of hydrocarbons from oil to water. On a dilution basis, the differences in toxicity among the four oils were correlated with the concentrations in oil of polynuclear aromatic hydrocarbons (PAH), particularly those with three to five rings, and with their viscosity, an index of dispersibility. However, when PAH concentrations were measured in solution, toxicity did not vary substantially among the four oils, suggesting that the PAH of each oil had equivalent toxicities and that differences in toxicity represented differences in dispersability. PMID:22213001

  4. Sources of toxicity and exposure information for identifying chemicals of high concern to children

    SciTech Connect

    Stone, Alex; Delistraty, Damon

    2010-11-15

    Due to the large number of chemicals in commerce without adequate toxicity characterization data, coupled with an ineffective federal policy for chemical management in the United States, many states are grappling with the challenge to identify toxic chemicals that may pose a risk to human health and the environment. Specific populations (e.g., children, elderly) are particularly sensitive to these toxic chemicals. In 2008, the Children's Safe Product Act (CSPA) was passed in Washington State. The CSPA included specific requirements to identify High Priority Chemicals (HPCs) and Chemicals of High Concern to Children (CHCCs). To implement this legislation, a methodology was developed to identify HPCs from authoritative scientific and regulatory sources on the basis of toxicity criteria. Another set of chemicals of concern was then identified from authoritative sources, based on their potential exposure to children. Exposure potential was evaluated by identifying chemicals detected in biomonitoring studies (i.e., human tissues), as well as those present in residential exposure media (e.g., indoor air, house dust, drinking water, consumer products). Accordingly, CHCCs were defined as HPCs that also appear in biomonitoring studies or relevant exposure media. For chemicals with unique Chemical Abstracts Service (CAS) numbers, we identified 2044 HPCs and 2219 chemicals with potential exposure to children, resulting in 476 CHCCs. The process of chemical identification is dynamic, so that chemicals may be added or subtracted as new information becomes available. Although beyond the scope of this paper, the 476 CHCCs will be prioritized in a more detailed assessment, based on the strength and weight of evidence of toxicity and exposure data. Our approach was developed to be flexible which allows the addition or removal of specific sources of toxicity or exposure information, as well as transparent to allow clear identification of inputs. Although the methodology was

  5. A Novel Water Delivery System for Administering Volatile Chemicals while Minimizing Chemical Waste in Rodent Toxicity Studies

    EPA Science Inventory

    Rodent toxicity studies typically use water bottles to administer test chemicals via drinking water. However, water bottles provide inconsistent exposure of volatile chemicals due to varying headspace, as well as lead to excessive waste of test material. In order to refine drin...

  6. A novel water delivery system for administering volatile chemicals while minimizing chemical waste in rodent toxicity sutdies

    EPA Science Inventory

    Rodent toxicity studies typically use water bottles to administer test chemicals via drinking water. However, water bottles provide inconsistent exposure of volatile chemicals due to varying headspace, as well as lead to excessive waste of test material. In order to refine drinki...

  7. Predictive Modeling of Chemical Hazard by Integrating Numerical Descriptors of Chemical Structures and Short-term Toxicity Assay Data

    PubMed Central

    Rusyn, Ivan; Sedykh, Alexander; Guyton, Kathryn Z.; Tropsha, Alexander

    2012-01-01

    Quantitative structure-activity relationship (QSAR) models are widely used for in silico prediction of in vivo toxicity of drug candidates or environmental chemicals, adding value to candidate selection in drug development or in a search for less hazardous and more sustainable alternatives for chemicals in commerce. The development of traditional QSAR models is enabled by numerical descriptors representing the inherent chemical properties that can be easily defined for any number of molecules; however, traditional QSAR models often have limited predictive power due to the lack of data and complexity of in vivo endpoints. Although it has been indeed difficult to obtain experimentally derived toxicity data on a large number of chemicals in the past, the results of quantitative in vitro screening of thousands of environmental chemicals in hundreds of experimental systems are now available and continue to accumulate. In addition, publicly accessible toxicogenomics data collected on hundreds of chemicals provide another dimension of molecular information that is potentially useful for predictive toxicity modeling. These new characteristics of molecular bioactivity arising from short-term biological assays, i.e., in vitro screening and/or in vivo toxicogenomics data can now be exploited in combination with chemical structural information to generate hybrid QSAR–like quantitative models to predict human toxicity and carcinogenicity. Using several case studies, we illustrate the benefits of a hybrid modeling approach, namely improvements in the accuracy of models, enhanced interpretation of the most predictive features, and expanded applicability domain for wider chemical space coverage. PMID:22387746

  8. Chemical composition of major ions in rainwater.

    PubMed

    Salve, P R; Maurya, A; Wate, S R; Devotta, Sukumar

    2008-03-01

    The present study investigated the chemical composition of rainwater at Kabir nagar, Nari, Nagpur, Maharashtra, India. The rainwater samples were collected on event basis during June-July-August-2006 and were analyzed for pH, major anions Cl, NO(3), SO(4)) and cations (Ca, Mg, Na, K, NH4). The pH value varied from 6.0 to 7.3 (avg. 6.3 +/- 0.3) indicating alkaline nature of rainwater. The pH of the rainwater was found well above the reference pH (5.6), showing alkalinity during the monsoon season. The average and standard deviation of ionic composition was found to be 98.1 +/- 10.6 micro eql(-1). The total anions contribute 45.1% and cations 54.9%, respectively to rainwater. Neutralization factors (NF) followed a sequence of NF(Ca) > NF(Mg) > NF(NH4) with factors of 1.1, 0.38 and 0.15 indicating the crustal components are responsible for neutralization of anions. The average ratio of (NO(3) + Cl)/SO(4) observed as 1.1 indicates that nitric and hydrochloric acid influences the acidity of rainwater. The ratio of NH(4)/NO(3) and NH(4)/SO(4) was observed as 0.68 and 0.34 indicate that the possible compounds which may predominate in the atmosphere are NH(4)NO(3) and (NH(4))(2)SO(4). Ionic correlation was established to identify sources of origin. A good correlation was seen between Ca and Mg (r = 0.95); suggesting the common occurrence of these ions from crustal origin. Similarly, the acidic ions SO(4) and NO(3) correlated well (r = 0.60) indicating their origin from similar sources. Other relatively significant correlations were observed between Ca and SO4 (r = 0.92), Mg and SO(4) (r = 0.83), Ca and NO(3) (r = 0.09), Ca and Cl (r = 0.34) and Mg and Cl (r = 0.31), and Mg and NO(3) (r = 0.71). The observed rainwater ratio of Cl/Na (1.1) is closer to that of seawater ratio (1.16) indicates fractionation of sea-salt and modifications by non-marine constituents as the site is 834 km away from the sea coast. The nss-Ca contribution was observed as 95.7% suggesting their

  9. Fate of chemical warfare agents and toxic industrial chemicals in landfills.

    PubMed

    Bartelt-Hunt, Shannon L; Barlaz, Morton A; Knappe, Detlef R U; Kjeldsen, Peter

    2006-07-01

    One component of preparedness for a chemical attack is planning for the disposal of contaminated debris. To assess the feasibility of contaminated debris disposal in municipal solid waste (MSW) landfills, the fate of selected chemical warfare agents (CWAs) and toxic industrial chemicals (TICs) in MSW landfills was predicted with a mathematical model. Five blister agents [sulfur mustard (HD), nitrogen mustard (HN-2), lewisite (L), ethyldichloroarsine (ED), and phosgene oxime (CX)], eight nerve agents [tabun (GA), sarin (GB), soman (GD), GE, GF, VX, VG, and VM], one riot-control agent [CS], and two TICs [furan and carbon disulfide] were studied. The effects of both infiltration (climate) and contaminant biodegradability on fate predictions were assessed. Model results showed that hydrolysis and gas-phase advection were the principal fate pathways for CWAs and TICs, respectively. Apart from CX and the TICs, none of the investigated compounds was predicted to persist in a landfill for more than 5 years. Climate had little impact on CWA/TIC fate, and biodegradability was only important for compounds with long hydrolysis half-lives. Monte Carlo simulations were performed to assess the influence of uncertainty in model input parameters on CWA/TIC fate predictions. Correlation analyses showed that uncertainty in hydrolysis rate constants was the primary contributor to variance of CWA fate predictions, while uncertainty in the Henry's Law constant and landfill gas-production rate accounted for most of the variance of TIC fate predictions. CWA hydrolysates were more persistent than the parent CWAs, but limited information is available on abiotic or biotic transformation rates for these chemicals. PMID:16856738

  10. Toxicity and utilization of chemical weapons: does toxicity and venom utilization contribute to the formation of species communities?

    PubMed Central

    Westermann, Fabian L; McPherson, Iain S; Jones, Tappey H; Milicich, Lesley; Lester, Philip J

    2015-01-01

    Toxicity and the utilization of venom are essential features in the ecology of many animal species and have been hypothesized to be important factors contributing to the assembly of communities through competitive interactions. Ants of the genus Monomorium utilize a variety of venom compositions, which have been reported to give them a competitive advantage. Here, we investigate two pairs of Monomorium species, which differ in the structural compositions of their venom and their co-occurrence patterns with the invasive Argentine ant. We looked at the effects of Monomorium venom toxicity, venom utilization, and aggressive physical interactions on Monomorium and Argentine ant survival rates during arena trials. The venom toxicity of the two species co-occurring with the invasive Argentine ants was found to be significantly higher than the toxicity of the two species which do not. There was no correlation between venom toxicity and Monomorium survival; however, three of the four Monomorium species displayed significant variability in their venom usage which was associated with the number of Argentine ant workers encountered during trials. Average Monomorium mortality varied significantly between species, and in Monomorium smithii and Monomorium antipodum, aggressive interactions with Argentine ants had a significant negative effect on their mortality. Our study demonstrates that different factors and strategies can contribute to the ability of a species to withstand the pressure of a dominant invader at high abundance, and venom chemistry appears to be only one of several strategies utilized. PMID:26357539

  11. Chemical Composition of Fresh and Aged Biochars

    NASA Astrophysics Data System (ADS)

    Cooper, W. T.; Hamdan, R.; Mukherjee, A.; Zimmerman, A. R.

    2014-12-01

    It is possible to manipulate the chemical and physical properties of pyrogenic organic matter ('black carbon' or 'biochar') during its production and tailor its composition for intended environmental management applications. In this study biochars made from grass (Tripsacum floridanum), oak (Quercus lobata), and pine (Pinus taeda) at 250 ºC in air and 400 and 650 ºC under N2 were characterized by solid state 13C-NMR spectroscopy and desorption atmospheric pressure photoionization mass spectrometry. Among the biochars produced, those originating from pine showed distinct characteristics, with greater amounts of oxygenated aromatic clusters after low temperature combustion and more condensed aromatic clusters after higher temperature pyrolysis. Although a mixture of small and large aromatic clusters occurred across the temperature profile, cluster size increased and functionality decreased with increasing combustion temperature (Figure 1). At medium and high temperatures, aromatic clusters of up to 60- carbon aromatic rings inter-connected with small chains dominated the biochars examined. These structures are intermediate in size between the linearly condensed structures and the predominantly condensed aromatic clusters proposed in earlier studies. Field aging of the pure biochars for 15 months decreased the total acid functional group content as determined by Boehm titration, but solid-state 13C-NMR analyses suggested the creation and transformation of a range of functional groups via leaching, oxidation, and addition of microbially-produced organic matter. Similar trends were observed when the biochars were mixed with soils, suggesting that the same biochar aging processes occurred in the soil environment. These findings demonstrate that biochar transformations occur over time through a multitude of processes that are both biochar and soil type-dependent.

  12. VAPOR SAMPLING DEVICE FOR INTERFACE WITH MICROTOX ASSAY FOR SCREENING TOXIC INDUSTRIAL CHEMICALS

    EPA Science Inventory

    A time-integrated sampling system interfaced with a toxicity-based assay is reported for monitoring volatile toxic industrial chemicals (TICs). Semipermeable membrane devices (SPMDs) using dimethyl sulfoxide (DMSO) as the fill solvent accumulated each of 17 TICs from the vapor...

  13. QUANTITATIVE STRUCTURE ACTIVITY RELATIONSHIP (QSAR) MODELS TO PREDICT CHEMICAL TOXICITY FOR VARIOUS HEALTH ENDPOINTS

    EPA Science Inventory

    Although ranking schemes based on exposure and toxicity have been developed to aid in the prioritization of research funds for identifying chemicals of regulatory concern, there are significant gaps in the availability of experimental toxicity data for most health endpoints. Pred...

  14. Estimating Toxicity Pathway Activating Doses for High Throughput Chemical Risk Assessments

    EPA Science Inventory

    Estimating a Toxicity Pathway Activating Dose (TPAD) from in vitro assays as an analog to a reference dose (RfD) derived from in vivo toxicity tests would facilitate high throughput risk assessments of thousands of data-poor environmental chemicals. Estimating a TPAD requires def...

  15. Computational Molecular Modeling for Evaluating the Toxicity of Environmental Chemicals: Prioritizing Bioassay Requirements

    EPA Science Inventory

    This commentary provides an overview of the challenges that arise from applying molecular modeling tools developed and commonly used for pharmaceutical discovery to the problem of predicting the potential toxicities of environmental chemicals.

  16. EPA'S TOXCAST PROGRAM FOR PREDICTING HAZARD AND PRIORITIZING TOXICITY TESTING OF ENVIRONMENTAL CHEMICALS

    EPA Science Inventory

    EPA is developing methods for utilizing computational chemistry, high-throughput screening (HTS) and various toxicogenomic technologies to predict potential for toxicity and prioritize limited testing resources towards chemicals that likely represent the greatest hazard to human ...

  17. EPA's Toxcast ™ Program for Predicting Hazard and Priortizing Toxicity Testing of Environemntal Chemicals (T)

    EPA Science Inventory

    EPA is developing methods for utilizing computational chemistry, high-throughput screening (HTS) and various toxicogenomic technologies to predict potential for toxicity and prioritize limited testing resources towards chemicals that likely represent the greatest hazard to human ...

  18. CHEMICAL STRUCTURE INDEXING OF TOXICITY DATA ON THE INTERNET: MOVING TOWARDS A FLAT WORLD

    EPA Science Inventory

    Standardized chemical structure annotation of public toxicity databases and information resources is playing an increasingly important role in the 'flattening' and integration of diverse sets of biological activity data on the Internet. This review discusses public initiatives th...

  19. ToxCast: Developing Predictive Signatures of Chemically Induced Toxicity (S)

    EPA Science Inventory

    ToxCast, the United States Environmental Protection Agency’s chemical prioritization research program, is developing methods for utilizing computational chemistry, bioactivity profiling and toxicogenomic data to predict potential for toxicity and prioritize limited testing resour...

  20. Toxicity testing and chemical analyses of recycled fibre-based paper for food contact.

    PubMed

    Binderup, M L; Pedersen, G A; Vinggaard, A M; Rasmussen, E S; Rosenquist, H; Cederberg, T

    2002-01-01

    Food-contact materials, including paper, have to comply with a basic set of criteria concerning safety. This means that paper for food contact should not give rise to migration of components, which can endanger human health. The objectives of this pilot study were, first, to compare paper of different qualities as food-contact materials and to perform a preliminary evaluation of their suitability, from a safety point of view, and, second, to evaluate the use of different in vitro toxicity tests for screening of paper and board. Paper produced from three different categories of recycled fibres (B-D) and a raw material produced from virgin fibres (A) were obtained from industry, and extracts were examined by chemical analyses and diverse in vitro toxicity test systems. The products tested were either based on different raw materials or different treatments were applied. Paper category B was made from 40% virgin fibres, 40% unprinted cuttings from newspapers, and 20% de-inked newspapers and magazines. Paper categories C and D were based on newspapers and magazines. However, paper D was de-inked, whereas C was not. To identify constituents of the papers with a potential to migrate into foodstuff, samples of the paper products were extracted with either 99% ethanol or water. Potential migrants in the extracts were identified and semiquantified by GC-IR-MS or GC-HRMS. In parallel to the chemical analyses, a battery of four different in vitro toxicity tests with different endpoints were applied to the same extracts. (1) a cytotoxicity test using normal human skin fibroblasts. The test was based on measurements of the reduction of resazurin to resorufin by cellular redox processes and used as a screening test for acute or general toxicity; (2) a Salmonella/microsome assay (Ames test) as a screening test for mutagenic and potentially carcinogenic compounds; (3) a recombinant yeast cell bioassay as a screening test for compounds with oestrogenic activity; (4) an aryl

  1. Alterations in welding process voltage affect the generation of ultrafine particles, fume composition, and pulmonary toxicity.

    PubMed

    Antonini, James M; Keane, Michael; Chen, Bean T; Stone, Samuel; Roberts, Jenny R; Schwegler-Berry, Diane; Andrews, Ronnee N; Frazer, David G; Sriram, Krishnan

    2011-12-01

    The goal was to determine if increasing welding voltage changes the physico-chemical properties of the fume and influences lung responses. Rats inhaled 40 mg/m³ (3 h/day × 3 days) of stainless steel (SS) welding fume generated at a standard voltage setting of 25 V (regular SS) or at a higher voltage (high voltage SS) of 30 V. Particle morphology, size and composition were characterized. Bronchoalveolar lavage was performed at different times after exposures to assess lung injury. Fumes collected from either of the welding conditions appeared as chain-like agglomerates of nanometer-sized primary particles. High voltage SS welding produced a greater number of ultrafine-sized particles. Fume generated by high voltage SS welding was higher in manganese. Pulmonary toxicity was more substantial and persisted longer after exposure to the regular SS fume. In summary, a modest raise in welding voltage affected fume size and elemental composition and altered the temporal lung toxicity profile.

  2. Toxicity of organic chemical pollution in groundwater downgradient of a landfill (Grindsted, Denmark)

    SciTech Connect

    Baun, A.; Jensen, S.D.; Bjerg, P.L.; Christensen, T.H.; Nyholm, N.

    2000-05-01

    The aim of the present study was to describe the occurrence and distribution of toxicity related to organic chemical contaminants in the leachate plume downgradient of the Grindsted Landfill (Denmark). A total of 27 groundwater samples were preconcentrated by solid-phase extraction (SPE) using XAD-2 as the resin material. This treatment effectively eliminated sample matrix toxicity caused by inorganic salts and natural organic compounds and produced an aqueous concentrate of the nonvolatile chemical contaminants. The SPE extracts were tested in a battery of standardized short-term aquatic toxicity tests with luminescent bacteria (Vibrio fischeri), algae (Selenastrum capricornutum), and crustaceans (Daphnia magna). Additional genotoxicity tests were made using the umuC test (Salmonella typhimurium). Biotests with algae and luminescent bacteria were the most sensitive tests. On the basis of results with these two bioassays, it was concluded that SPE extracts of groundwater collected close to the landfill were toxic. The toxicity decreased with the distance from the landfill. At distances greater than 80 m from the border of the landfill, the groundwater toxicity was not significantly different from the background toxicity. SPE extracts were not toxic to Daphnia, and no genotoxicity was observed in the umuC test. The overall findings indicate that a battery of biotests applied on preconcentrated groundwater samples can be a useful tool for toxicity characterization and hazard ranking of groundwater polluted with complex chemical mixtures, such as landfill leachates.

  3. Discovery of Chemical Toxicity via Biological Networks and Systems Biology

    SciTech Connect

    Perkins, Edward; Habib, Tanwir; Guan, Xin; Escalon, Barbara; Falciani, Francesco; Chipman, J.K.; Antczak, Philipp; Edwards, Stephen; Taylor, Ronald C.; Vulpe, Chris; Loguinov, Alexandre; Van Aggelen, Graham; Villeneuve, Daniel L.; Garcia-Reyero, Natalia

    2010-09-30

    Both soldiers and animals are exposed to many chemicals as the result of military activities. Tools are needed to understand the hazards and risks that chemicals and new materials pose to soldiers and the environment. We have investigated the potential of global gene regulatory networks in understanding the impact of chemicals on reproduction. We characterized effects of chemicals on ovaries of the model animal system, the Fathead minnow (Pimopheles promelas) connecting chemical impacts on gene expression to circulating blood levels of the hormones testosterone and estradiol in addition to the egg yolk protein vitellogenin. We describe the application of reverse engineering complex interaction networks from high dimensional gene expression data to characterize chemicals that disrupt the hypothalamus-pituitary-gonadal endocrine axis that governs reproduction in fathead minnows. The construction of global gene regulatory networks provides deep insights into how drugs and chemicals effect key organs and biological pathways.

  4. Chemical-chemical interaction between cyanogenic toxicants and aldehydes: a mechanism-based QSAR approach to assess toxicological joint effects.

    PubMed

    Lin, Z; Wei, D; Wang, X; Yin, K; Zhao, D

    2004-04-01

    A QSAR approach was proposed to assess toxicological joint effects based on the mechanism of chemical-chemical interactions between cyanogenic toxicants and aldehydes. It has been observed that the chemical-chemical interaction between cyanogenic toxicants and aldehydes resulted in the formation of carbanion intermediates, and therefore this interaction led to different toxicological joint effects between cyanogenic toxicants and aldehydes. Analysis of this chemical-chemical interaction showed that the formation of carbanion intermediate highly depended on the charge of the carbon atom in the -CHO of aldehydes and this of the carbon atom (C*) in the carbochain of cyanogenic toxicant. By using the Hammett Constant (sigma(p)) to measure the charge of carbon atom in the -CHO of aldehydes, a mechanism-based QSAR approach (M = 0.316 - 4.386sigma(p) with r2 = 0.933, SE = 0.082, F = 55.389, p = 0.002, M = sum of toxic units) was proposed to assess the toxicological joint effects between alpha-hydroxy-isobutyronitrile and individual aliphatic aldehydes. Another one (M = 0.978 - 0.720sigma(p) with r2 = 0.852, SE = 0.152, F = 40.148, p = 0.0001) was also proposed to assess the toxicological joint effects between alpha-hydroxy-isobutyronitrile and individual aromatic aldehydes. Lastly, by using the charge of carbon atom (C*) in the carbochain of cyanogenic toxicant, a mechanism-based QSAR model (M = -0.161 - 7.721C* with r2 = 0.847, SE = 0.227, F = 27.657, p = 0.003) was derived to assess toxicological joint effects between p-nitrobenzaldehyde and cyanogenic toxicants.

  5. Role of initial cell density of algal bioassay of toxic chemicals.

    PubMed

    Singh, Prashant Kumar; Shrivastava, Alok Kumar

    2016-07-01

    A variety of toxicants such as, metal ions, pesticides, dyes, etc. are continuously being introduced anthropogenically in the environment and adversely affect to the biotic component of the ecosystem. Therefore, the assessment of negative effects of these toxicants is required. However, toxicity assessment anticipated by chemical analysis are extremely poor, therefore the application of the living systems for the same is an excellent approach. Concentration of toxicant as well as cell density both influenced the result of the algal toxicity assay. Here, Scenedesmus sp, a very fast growing green microalgae was selected for study the effects of initial cell densities on the toxicity of Cu(II), Cd(II), Zn(II), paraquat and 2,4-D. Results demonstrated concentration dependent decrease in biomass and specific growth rate of Scenedesmus sp. on exposure of abovesaid toxicants. Paraquat and 2,4-D emerged as extremely toxic to the test alga which reflected from the lowest EC value and very steep decline in biomass was evident with increasing concentration of paraquat and 2,4-D in the medium. Result also demonstrated that initial cell density is a very important parameter than specific growth rate for algal bioassay of various toxicants. Present study clearly illustrated that the use of smaller cell density is always recommended for assaying toxicity of chemicals in algal assays. PMID:26593761

  6. Meta-analysis of aquatic chronic chemical toxicity data

    EPA Science Inventory

    Chronic toxicity data from the open literature and from tests submitted for pesticide registration were extracted and assembled into a database, AquaChronTox, with a flexible search interface. Data were captured at a treatment and, when available, replicate level to support conc...

  7. DIFFERENTIATING MECHANISMS OF REACTIVE CHEMICAL TOXICITY IN ISOLATED TROUT HEPATOCYTES

    EPA Science Inventory

    The toxicity of four quinones, 2,3-dimethoxy-1,4-naphthoquinone (DMONQ), 2-methyl 1,4-naphthoquinone (MNQ ),1,4-naphthoquinone (NQ), and 1,4-benzoquinone (BQ), which redox cycle or arlyate in mammalian cells, was determined in isolated trout (Oncorhynchus mykiss) hepatocytes. Mor...

  8. Origin and chemical composition of evaporite deposits

    USGS Publications Warehouse

    Moore, George William

    1960-01-01

    A comparative study of marine evaporite deposits forming at the present time along the pacific coast of central Mexico and evaporite formations of Permian age in West Texas Basin was made in order to determine if the modern sediments provide a basis for understanding environmental conditions that existed during deposition of the older deposits. The field work was supplemented by investigations of artificial evaporite minerals precipitated in the laboratory and by study of the chemical composition of halite rock of different geologic ages. The environment of deposition of contemporaneous marine salt deposits in Mexico is acidic, is strongly reducing a few centimeters below the surface, and teems with microscopic life. Deposition of salt, unlike that of many other sediments, is not wholly a constructional phenomenon. Permanent deposits result only if a favorable balance exists between deposition in the dry season and dissolution in the wet season. Evaporite formations chosen for special study in the West Texas Basin are, in ascending order, the Castile, Salado, and Rustler formations, which have a combined thickness of 1200 meters. The Castile formation is largely composed of gypsum rock, the Salado, halite rock, and the Rustler, quartz and carbonate sandstone. The lower part of the Castile formation is bituminous and contains limestone laminae. The Castile and Rustler formations thicken to the south at the expense of salt of the intervening Salado formation. The clastic rocks of the Rustler formation are interpreted as the deposits of a series of barrier islands north of which halite rock of the Salado was deposited. The salt is believed to have formed in shallow water of uniform density that was mixed by the wind. Where water depth exceeded the depth of the wind mixing, density stratification developed, and gypsum was deposited. Dense water of high salinity below the density discontinuity was overlain by less dense, more normally saline water which was derived from

  9. Aquatic toxicity of forty industrial chemicals: Testing in support of hazardous substance spill prevention regulation

    NASA Astrophysics Data System (ADS)

    Curtis, M. W.; Ward, C. H.

    1981-05-01

    The U.S. Environmental Protection Agency is presently developing hazardous substance spill regulations to help prevent water pollution. Aquatic animal toxicity data are used as criteria for the designation and categorization of substances as hazardous, even though this type of data is not available for many industrial chemicals. Static 96-hr. toxicity tests were conducted with 40 such chemicals to provide basic toxicity data for regulatory decision making. Thirty-two of the 40 chemicals tested were hazardous to aquatic life as determined by 96-hr. LC 50's less than or equal to 500 mg/l. All 40 chemicals were tested with the fresh-water fathead minnow, Pimephales promelas, and ten chemicals were also tested with the salt-water grass shrimp, Palaemonetes pugio.

  10. Propolis chemical composition and honeybee resistance against Varroa destructor.

    PubMed

    Popova, M; Reyes, M; Le Conte, Y; Bankova, V

    2014-01-01

    Propolis is known as honeybee chemical defence against infections and parasites. Its chemical composition is variable and depends on the specificity of the local flora. However, there are no data concerning the relationship between propolis chemical composition and honeybee colony health. We tried to answer this question, studying the chemical composition of propolis of bee colonies from an apiary near Avignon, which are tolerant to Varroa destructor, comparing it with colonies from the same apiary which are non-tolerant to the mites. The results indicated that non-tolerant colonies collected more resin than the tolerant ones. The percentage of four biologically active compounds - caffeic acid and pentenyl caffeates - was higher in propolis from tolerant colonies. The results of this study pave the way to understanding the effect of propolis in individual and social immunity of the honeybees. Further studies are needed to clarify the relationship between propolis chemical composition and honeybee colony health.

  11. Acute toxicity of fire control chemicals to Daphnia magna (Straus) and Selenastrum capricornutum (Printz).

    PubMed

    McDonald, S F; Hamilton, S J; Buhl, K J; Heisinger, J F

    1996-02-01

    Acute toxicity tests were conducted exposing Daphnia magna Straus (daphnid) in soft and hard reconstituted waters (hardness 42 and 162 mg/liter as CaCO3, respectively), and Selenastrum capricornutum Printz (algae) in ASTM algal assay medium (hardness 15 mg/liter as CaCO3) to fire retardants Fire-Trol GTS-R, Fire-Trol LCG-R, and Phos-Chek D75-F, and foam suppressants Phos-Check WD-881 and Silv-Ex. The chemicals were slightly toxic to practically harmless to daphnids and moderately toxic to algae. Water quality did not consistently alter the toxicity of the test chemicals to daphnids. The most toxic chemical to daphnids was Silv-Ex (48-hr EC50 7 mg/liter in soft and hard waters), whereas the least toxic chemical to daphnids was Fire-Trol LCG-R (48-hr EC50 848 mg/liter in soft water, 813 mg/liter in hard water). The most toxic chemical to algae was Fire-Trol LCG-R (96-hr IC50 10 mg/liter), and the least toxic chemical was Phos-Chek D75-F (96-hr IC50 79 mg/liter). Un-ionized ammonia concentrations near the EC50 or IC50 value in tests with the Fire-Trol compounds were frequently equal to or above reported LC50 un-ionized ammonia concentrations. Un-ionized ammonia concentrations in tests with Phos-Chek D75-F were low, thus other toxic components present in the compounds probably contributed to the toxicity. When compared to the daphnids tested in ASTM soft water, the Fire-Trol compounds were most toxic to algae, whereas Phos-Chek D75-F and the foam suppressants were most toxic to daphnids. The results of these tests are comparable to those obtained from research conducted in other laboratories with the same species and similar chemicals. Accidental entry of fire-fighting chemicals into aquatic environments could adversely affect algae and aquatic invertebrates, thus disrupting ecosystem function. PMID:8744925

  12. Acute toxicity of fire control chemicals to Daphnia magna(Straus) and Selenastrum capricornutum(Printz)

    USGS Publications Warehouse

    McDonald, Susan F.; Hamilton, Steven J.; Buhl, Kevin J.; Heisinger, James F.

    1996-01-01

    Acute toxicity tests were conducted exposingDaphnia magnaStraus (daphnid) in soft and hard reconstituted waters (hardness 42 and 162 mg/liter as CaCO3, respectively), andSelenastrum capricornutumPrintz (algae) in ASTM algal assay medium (hardness 15 mg/liter as CaCO3) to fire retardants Fire-Trol GTS-R, Fire-Trol LCG-R, and Phos-Chek D75-F, and foam suppressants Phos-Chek WD-881 and Silv-Ex. The chemicals were slightly toxic to practically harmless to daphnids and moderately toxic to algae. Water quality did not consistently alter the toxicity of the test chemicals to daphnids. The most toxic chemical to daphnids was Silv-Ex (48-hr EC507 mg/liter in soft and hard waters), whereas the least toxic chemical to daphnids was Fire-Trol LCG-R (48-hr EC50848 mg/liter in soft water, 813 mg/liter in hard water). The most toxic chemical to algae was Fire-Trol LCG-R (96-hr IC5010 mg/liter), and the least toxic chemical was Phos-Chek D75-F (96-hr IC5079 mg/liter). Un-ionized ammonia concentrations near the EC50or IC50value in tests with the Fire-Trol compounds were frequently equal to or above reported LC50un-ionized ammonia concentrations. Un-ionized ammonia concentrations in tests with Phos-Chek D75-F were low, thus other toxic components present in the compounds probably contributed to the toxicity. When compared to the daphnids tested in ASTM soft water, the Fire-Trol compounds were most toxic to algae, whereas Phos-Chek D75-F and the foam suppressants were most toxic to daphnids. The results of these tests are comparable to those obtained from research conducted in other laboratories with the same species and similar chemicals. Accidental entry of fire-fighting chemicals into aquatic environments could adversely affect algae and aquatic invertebrates, thus disrupting ecosystem function.

  13. Variation in chemical composition and acaricidal activity against Dermanyssus gallinae of four eucalyptus essential oils.

    PubMed

    George, David R; Masic, Dino; Sparagano, Olivier A E; Guy, Jonathan H

    2009-06-01

    The results of this study suggest that certain eucalyptus essential oils may be of use as an alternative to synthetic acaricides in the management of the poultry red mite, Dermanyssus gallinae. At a level of 0.21 mg/cm(2), the essential oil from Eucalyptus citriodora achieved 85% mortality in D. gallinae over a 24 h exposure period in contact toxicity tests. A further two essential oils from different eucalyptus species, namely E. globulus and E. radiata, provided significantly (P < 0.05) lower mite mortality (11 and 19%, respectively). Notable differences were found between the eucalyptus essential oils regarding their chemical compositions. There appeared to be a trend whereby the essential oils that were composed of the fewer chemical components were the least lethal to D. gallinae. It may therefore be the case that the complexity of an essential oil's chemical make up plays an important role in dictating the toxicity of that oil to pests such as D. gallinae.

  14. A novel water delivery system for administering volatile chemicals while minimizing chemical waste in rodent toxicity studies.

    PubMed

    McDonald, A; Killough, P; Puckett, E; Best, D S; Simmons, J E; Pressman, J G; Narotsky, M G

    2010-01-01

    Rodent toxicity studies typically use water bottles to administer test chemicals via drinking water. However, water bottles provide inconsistent exposure of volatile chemicals due to varying headspace, and lead to excessive waste of test material. To refine drinking water toxicity studies in rodents by enhancing sample quality and consistency, and minimizing waste, we designed and implemented a novel water delivery system that keeps the water chilled, headspace free and protected from light. Materials used were resistant to chemical interaction. In this gravity-fed system, a 6-L Teflon water bag, stored in a polystyrene cooler on the cage rack, was connected to a stainless steel manifold delivering water to five cages via specialized drinking valves. Due to the absence of headspace in the water bag, this system allows consistent exposure of volatile chemicals. In addition, small diameter tubing throughout the system reduces the amount of test material residing in the system and minimizes chemical waste. PMID:19858168

  15. Comparison of toxicity values across zebrafish early life stages and mammalian studies: Implications for chemical testing.

    PubMed

    Ducharme, Nicole A; Reif, David M; Gustafsson, Jan-Ake; Bondesson, Maria

    2015-08-01

    With the high cost and slow pace of toxicity testing in mammals, the vertebrate zebrafish has become a tractable model organism for high throughput toxicity testing. We present here a meta-analysis of 600 chemicals tested for toxicity in zebrafish embryos and larvae. Nineteen aggregated and 57 individual toxicity endpoints were recorded from published studies yielding 2695 unique data points. These data points were compared to lethality and reproductive toxicology endpoints analyzed in rodents and rabbits and to exposure values for humans. We show that although many zebrafish endpoints did not correlate to rodent or rabbit acute toxicity data, zebrafish could be used to accurately predict relative acute toxicity through the rat inhalation, rabbit dermal, and rat oral exposure routes. Ranking of the chemicals based on toxicity and teratogenicity in zebrafish, as well as human exposure levels, revealed that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), benzo(a)pyrene, and chlorpyrifos ranked in the top nine of all chemicals for these three categories, and as such should be considered high priority chemicals for testing in higher vertebrates. PMID:25261610

  16. Comparison of toxicity values across zebrafish early life stages and mammalian studies: Implications for chemical testing.

    PubMed

    Ducharme, Nicole A; Reif, David M; Gustafsson, Jan-Ake; Bondesson, Maria

    2015-08-01

    With the high cost and slow pace of toxicity testing in mammals, the vertebrate zebrafish has become a tractable model organism for high throughput toxicity testing. We present here a meta-analysis of 600 chemicals tested for toxicity in zebrafish embryos and larvae. Nineteen aggregated and 57 individual toxicity endpoints were recorded from published studies yielding 2695 unique data points. These data points were compared to lethality and reproductive toxicology endpoints analyzed in rodents and rabbits and to exposure values for humans. We show that although many zebrafish endpoints did not correlate to rodent or rabbit acute toxicity data, zebrafish could be used to accurately predict relative acute toxicity through the rat inhalation, rabbit dermal, and rat oral exposure routes. Ranking of the chemicals based on toxicity and teratogenicity in zebrafish, as well as human exposure levels, revealed that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), benzo(a)pyrene, and chlorpyrifos ranked in the top nine of all chemicals for these three categories, and as such should be considered high priority chemicals for testing in higher vertebrates.

  17. Children's vulnerability to toxic chemicals: a challenge and opportunity to strengthen health and environmental policy.

    PubMed

    Landrigan, Philip J; Goldman, Lynn R

    2011-05-01

    A key policy breakthrough occurred nearly twenty years ago with the discovery that children are far more sensitive than adults to toxic chemicals in the environment. This finding led to the recognition that chemical exposures early in life are significant and preventable causes of disease in children and adults. We review this knowledge and recommend a new policy to regulate industrial and consumer chemicals that will protect the health of children and all Americans, prevent disease, and reduce health care costs. The linchpins of a new US chemical policy will be: first, a legally mandated requirement to test the toxicity of chemicals already in commerce, prioritizing chemicals in the widest use, and incorporating new assessment technologies; second, a tiered approach to premarket evaluation of new chemicals; and third, epidemiologic monitoring and focused health studies of exposed populations.

  18. Automated manometric method to assess anaerobic toxicity of chemicals.

    PubMed

    Fdz-Polanco, F; Nieto, P; Pérez-Elvira, S I; Fdz-Polanco, M

    2006-01-01

    Industrial additives eventually used for different purposes (antifoaming, cleaning, bactericides, antiscale, etc) are discharged to the wastewater treatment plant. The anaerobic toxicity of these commercial products is not provided by suppliers. A new manometric method is developed and tested to evaluate anaerobic toxicity or inhibition using four different commercial products. Antifoaming Cleron 6 (50-200 ppm), bactericide Divosan-forte (0.05-1.0% v/v), bleach (0.1-1.0% v/v) and cleaning agent Topax 66 (0.10-1.0% v/v). According to the different methods proposed in the literature, from the methane production rate, it is possible to calculate both methanogenic activity evolution and final substrate removal and quantify the potential inhibitory effect of commercial additives. The experimental method is simple and reliable.

  19. Quantitative structure-activity relationships for toxicity of nonpolar narcotic chemicals to Pseudokirchneriella subcapitata.

    PubMed

    Hsieh, Shih-Hung; Hsu, Chih-Hsiung; Tsai, Din-Yu; Chen, Chung-Yuan

    2006-11-01

    This study presents data for 27 nonpolar narcotic compounds regarding toxicity to Pseudokirchneriella subcapitata as evaluated using a closed-system algal toxicity test with an exposure time of 48 h. Two test endpoints, dissolved oxygen production and algal growth rate, were used to assess the toxicity of nonpolar narcotic chemicals on algae. Hydrophobicity (1-octanol-water partition coefficient [K(OW)]) provided satisfactory descriptions for the toxicity of nonpolar narcotic compounds, and quantitative structure-activity relationships based on log K(OW) were established. The relative sensitivity of various aquatic organisms to nonpolar chemicals was as follows: P. subcapitata > Vibriofischeri > or = Nitrosomonas sp. > fathead minnow > Daphnia magna > polytox > activated sludge. In addition, linear relationships were found between the toxicity observed in P. subcapitata and other aquatic organisms, except in the case of Nitrosomonas sp. Therefore, for nonpolar toxicants, the closed-system technique applied in the present study can be an ideal surrogate for other tests, such as fathead minnow and D. magna, that are either time-consuming or labor-intensive. However, because the current toxicity database is based primarily on the conventional batch tests, it cannot provide adequate assessment regarding the effects of various organic toxicants. Therefore, more extensive research is needed to revise the database for the toxicity of organic compounds on phytoplankton using the closed-system technique.

  20. Integrated modeling systems to assess exposure and toxicity of chemicals in support of aquatic ecological risk assessment of methodologically challenging chemicals

    EPA Science Inventory

    From an exposure assessment perspective, persistent, bioaccumulative and toxic chemicals (PBTs) are some of the most challenging chemicals facing environmental decision makers today. Due to their general physico-chemical properties [e.g., high octanol-water partition coefficien...

  1. Exploring the heterologous genomic space for building, stepwise, complex, multicomponent tolerance to toxic chemicals.

    PubMed

    Zingaro, Kyle A; Nicolaou, Sergios A; Yuan, Yongbo; Papoutsakis, Eleftherios Terry

    2014-07-18

    Modern bioprocessing depends on superior cellular traits, many stemming from unknown genes and gene interactions. Tolerance to toxic chemicals is such an industrially important complex trait, which frequently limits the economic feasibility of producing commodity chemicals and biofuels. Chemical tolerance encompasses both improved cell viability and growth under chemical stress. Building upon the success of our recently reported semisynthetic stress response system expressed off plasmid pHSP (Heat Shock Protein), we probed the genomic space of the solvent tolerant Lactobacillus plantarum to identify genetic determinants that impart solvent tolerance in combination with pHSP. Using two targeted enrichments, one for superior viability and one for better growth under ethanol stress, we identified several beneficial heterologous DNA determinants that act synergistically with pHSP. In separate strains, a 209% improvement in survival and an 83% improvement in growth over previously engineered strains based on pHSP were thus generated. We then developed a composite phenotype of improved growth and survival by combining the identified L. plantarum genetic fragments. This demonstrates the concept for a sequential, iterative assembly strategy for building multigenic traits by exploring the synergistic effects of genetic determinants from a much broader genomic space. The best performing strain produced a 3.7-fold improved survival under 8% ethanol stress, as well as a 32% increase in growth under 4% ethanol. This strain also shows significantly improved tolerance to n-butanol. Improved solvent production is rarely examined in tolerance engineering studies. Here, we show that our system significantly improves ethanol productivity in a Melle-Boinot-like fermentation process.

  2. A simple, rapid, inexpensive assay for toxic chemicals using a bacterial indicator

    SciTech Connect

    Botsford, J.L.; Hillaker, T.; Robertson, B.; Gonzales, M.; Benavidez, M.; Jones, B.; Baker, R.; Steen, W.; Pacheco, F.; Homer, V.; Lucero, O.; Matthews, M.; Koehler, V.

    1996-12-31

    A simple test for toxic chemicals has been developed. Rhizobium meliloti is combined with the toxic chemical. A tetrazolium dye, MTT (3-[4,5-Dimethylthiazol-2-yl]2,5-diphenyl-tetrazolium bromide) is added. The bacterium reduces this dye, causing the optical absorbance to increase dramatically. The increase can be determined with a simple spectrophotometer. Toxic chemicals and minerals inhibit the reduction of the dye. Presumably the dye serves as a terminal electron acceptor for electron transport. Toxic substances presumably damage the electron transport system. The results compare favorably with published results of tests using the Microtox{trademark} assay and with the Polytox{trademark} assay. This assay is simpler and requires no specialized equipment. It should be possible to use this assay in a third world situation.

  3. Chemical transformation of toxic metals by a Psuedomonas strain from a toxic waste site

    SciTech Connect

    Choate, D.; Blake, R.; Revis, N. Oak Ridge Research Inst., TN )

    1991-03-11

    Pseudomonas maltophilia, 0-2, isolated from soil at a toxic waste site in Oak Ridge, TN, catalyzed the transformation and precipitation of numerous toxic metal cations and oxyanions. When a viable inoculum (1%) of 0-2 was introduced into LB broth containing 0.2 mM Hg(II), 1 mM Cr(VI), 40 mM Se(IV), 3 mM Pb(II), 3mM Au(III), 3mM Cd(II), 10mM Te(IV), or 4mM Ag(I), effective removal of the toxic metal was complete within 1, 1, 2, 2, 2, 4, 5, and 7 days, respectively. The NADPH-dependent reduction of Hg(II) was catalyzed by an inducible mercuric reductase. The reduction of selenite and tellurite to their insoluble elemental forms appeared to be mediated by an intracellular glutathione reductase that utilized the spontaneously-formed bis(glutathio)Se or bis(glutathio)Te, respectively, as pseudosubstrates. The biomolecules responsible for the remaining metal transformations are currently under investigation. This project could provide useful information toward the eventual exploitation of P. maltophilia and related organisms for the removal of toxic metal wastes from selected, heavily polluted sites.

  4. Proteomic analyses of the environmental toxicity of carcinogenic chemicals

    EPA Science Inventory

    Protein expression and posttranslational modifications consistently change in response to the exposure to environmental chemicals. Recent technological advances in proteomics provide new tools for more efficient characterization of protein expression and posttranslational modific...

  5. High Throughput Screening of Toxicity Pathways Perturbed by Environmental Chemicals

    EPA Science Inventory

    Toxicology, a field largely unchanged over the past several decades, is undergoing a significant transformation driven by a number of forces – the increasing number of chemicals needing assessment, changing legal requirements, advances in biology and computer science, and concern...

  6. Modeling Reproductive Toxicity for Chemical Prioritization into an Integrated Testing Strategy

    EPA Science Inventory

    The EPA ToxCast research program uses a high-throughput screening (HTS) approach for predicting the toxicity of large numbers of chemicals. Phase-I tested 309 well-characterized chemicals in over 500 assays of different molecular targets, cellular responses and cell-states. Of th...

  7. Probing the ToxCast Chemical Library for Predictive Signatures of Developmental Toxicity

    EPA Science Inventory

    EPA’s ToxCast™ project is profiling the in vitro bioactivity of chemical compounds to assess pathway-level and cell-based signatures that correlate with observed in vivo toxicity. We hypothesize that cell signaling pathways are primary targets for diverse environmental chemicals ...

  8. Probing the ToxCastTM Chemical Library for Predictive Signatures of Developmental Toxicity -NLTO Poster

    EPA Science Inventory

    EPA’s ToxCast™ project is profiling the in vitro bioactivity of chemical compounds to assess pathway-level and cell-based signatures that correlate with observed in vivo toxicity. We hypothesize that cell signaling pathways are primary targets for diverse environmental chemicals ...

  9. 48 CFR 52.223-13 - Certification of Toxic Chemical Release Reporting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... manufacture, process, or otherwise use any toxic chemicals listed in 40 CFR 372.65; □ (ii) The facility does... under section 313(f) of EPCRA, 42 U.S.C. 11023(f) (including the alternate thresholds at 40 CFR 372.27... Chemical Release Reporting. 52.223-13 Section 52.223-13 Federal Acquisition Regulations System...

  10. THE FUTURE OF TOXICOLOGY-PREDICTIVE TOXICOLOGY: AN EXPANDED VIEW OF CHEMICAL TOXICITY

    EPA Science Inventory

    A chemistry approach to predictive toxicology relies on structure−activity relationship (SAR) modeling to predict biological activity from chemical structure. Such approaches have proven capabilities when applied to well-defined toxicity end points or regions of chemical space. T...

  11. Toxic chemical release inventory at the Rocky Flats Environmental Technology Site

    SciTech Connect

    Leonard, R.J.

    1995-07-01

    The Rocky Flats Environmental Technology Site (Site) submits an annual Toxic Chemical Release Inventory (Form R) as required under the Emergency Planning and Community Right-to-Know Act (EPCRA). The Site uses a multi-step process for completing the Form R which includes developing a written procedure, determine thresholds, collection of chemical use and fate information, and peer review.

  12. How Much is Too Much? Toxic Chemicals in High School Labs.

    ERIC Educational Resources Information Center

    Nagel, Miriam C.

    1982-01-01

    Lists 37 chemicals classified as suspected carcinogens and suspected teratogens (chemicals capable of producing malformations in an embryo). Offers suggestions to high school chemistry teachers for conducting safe laboratory investigations by avoiding use of these potentially toxic materials. (Author/JN)

  13. Exploring the role of quantum chemical descriptors in modeling acute toxicity of diverse chemicals to Daphnia magna.

    PubMed

    Reenu; Vikas

    2015-09-01

    Various quantum-mechanically computed molecular and thermodynamic descriptors along with physico-chemical, electrostatic and topological descriptors are compared while developing quantitative structure-activity relationships (QSARs) for the acute toxicity of 252 diverse organic chemicals towards Daphnia magna. QSAR models based on the quantum-chemical descriptors, computed with routinely employed advanced semi-empirical and ab-initio methods, along with the electron-correlation contribution (CORR) of the descriptors, are analyzed for the external predictivity of the acute toxicity. The models with reliable internal stability and external predictivity are found to be based on the HOMO energy along with the physico-chemical, electrostatic and topological descriptors. Besides this, the total energy and electron-correlation energy are also observed as highly reliable descriptors, suggesting that the intra-molecular interactions between the electrons play an important role in the origin of the acute toxicity, which is in fact an unexplored phenomenon. The models based on quantum-chemical descriptors such as chemical hardness, absolute electronegativity, standard Gibbs free energy and enthalpy are also observed to be reliable. A comparison of the robust models based on the quantum-chemical descriptors computed with various quantum-mechanical methods suggests that the advanced semi-empirical methods such as PM7 can be more reliable than the ab-initio methods which are computationally more expensive.

  14. Exploring the role of quantum chemical descriptors in modeling acute toxicity of diverse chemicals to Daphnia magna.

    PubMed

    Reenu; Vikas

    2015-09-01

    Various quantum-mechanically computed molecular and thermodynamic descriptors along with physico-chemical, electrostatic and topological descriptors are compared while developing quantitative structure-activity relationships (QSARs) for the acute toxicity of 252 diverse organic chemicals towards Daphnia magna. QSAR models based on the quantum-chemical descriptors, computed with routinely employed advanced semi-empirical and ab-initio methods, along with the electron-correlation contribution (CORR) of the descriptors, are analyzed for the external predictivity of the acute toxicity. The models with reliable internal stability and external predictivity are found to be based on the HOMO energy along with the physico-chemical, electrostatic and topological descriptors. Besides this, the total energy and electron-correlation energy are also observed as highly reliable descriptors, suggesting that the intra-molecular interactions between the electrons play an important role in the origin of the acute toxicity, which is in fact an unexplored phenomenon. The models based on quantum-chemical descriptors such as chemical hardness, absolute electronegativity, standard Gibbs free energy and enthalpy are also observed to be reliable. A comparison of the robust models based on the quantum-chemical descriptors computed with various quantum-mechanical methods suggests that the advanced semi-empirical methods such as PM7 can be more reliable than the ab-initio methods which are computationally more expensive. PMID:26188798

  15. Acute toxicity of 54 industrial chemicals to sheepshead minnows (Cyprinodon variegatus)

    SciTech Connect

    Heitmuller, P.T.; Hollister, T.A.; Parrish, P.R.

    1981-12-01

    Toxicity tests were conducted with sheepshead minnows to develop a data base from which water quality criteria could be established and to help determine priorites for further reseach efforts. Chemicals were generally those used by industry in relatively large quantities that pose potential or suspected environmental hazards, such as, chlorinated benzenes, phenols, and phthalates. The acute toxicity of the 54 chemicals varied widely. The most toxic chemical groups were the chlorinated phenols and the chlorinated benzenes with 96-h LC50's (based on nominal concentrations) ranging from 1.7-5.4 ppm and 0.8-21 ppm, respectively. The most toxic chemical tested appeared to be 1,2,4,5-tetrachlorobenzene with a 96-h LC50 of 0.8 ppm (95% confidence limits of 0.7-1.1 ppm). The 96-h LC50 for pentachlorobenzene was the same (0.8 ppm; 95% confidence limits of 0.4-1.8 ppm), but its effect early in the exposure was not as severe as the effect of 1,2,4,5-tetrachlorobenzene. The majority of the chemicals had 96-h LC50's in the range of 10-500 ppm and were considered to be slightly toxic to practically nontoxic. Ten of the chemicals had no apparent effect at highest concentrations tested. (JMT)

  16. WOOD STOVE EMISSIONS: PARTICLE SIZE AND CHEMICAL COMPOSITION

    EPA Science Inventory

    The report summarizes wood stove particle size and chemical composition data gathered to date. [NOTE: In 1995, EPA estimated that residential wood combustion (RWC), including fireplaces, accounted for a significant fraction of national particulate matter with aerodynamic diameter...

  17. Conditional Toxicity Value (CTV) Predictor for Generating Toxicity Values for Data Sparse Chemicals (Poster)

    EPA Science Inventory

    Various stakeholders and expert groups, including the National Research Council in Science and Decisions, call for “default approaches to support risk estimation for chemicals lacking chemical-specific information.” This project aims to address this challenge through ...

  18. EPA’s ToxCast Program for Predicting Toxicity and Prioritizing Chemicals for Further Screening and Testing

    EPA Science Inventory

    Testing of environmental and industrial chemicals for toxicity potential is a daunting task because of the wide range of possible toxicity mechanisms. Although animal testing is one means of achieving broad toxicity coverage, evaluation of large numbers of chemicals is challengin...

  19. Development of quantitative interspecies toxicity relationship modeling of chemicals to fish.

    PubMed

    Fatemi, M H; Mousa Shahroudi, E; Amini, Z

    2015-09-01

    In this work, quantitative interspecies-toxicity relationship methodologies were used to improve the prediction power of interspecies toxicity model. The most relevant descriptors selected by stepwise multiple linear regressions and toxicity of chemical to Daphnia magna were used to predict the toxicities of chemicals to fish. Modeling methods that were used for developing linear and nonlinear models were multiple linear regression (MLR), random forest (RF), artificial neural network (ANN) and support vector machine (SVM). The obtained results indicate the superiority of SVM model over other models. Robustness and reliability of the constructed SVM model were evaluated by using the leave-one-out cross-validation method (Q(2)=0.69, SPRESS=0.822) and Y-randomization test (R(2)=0.268 for 30 trail). Furthermore, the chemical applicability domains of these models were determined via leverage approach. The developed SVM model was used for the prediction of toxicity of 46 compounds that their experimental toxicities to a fish were not being reported earlier from their toxicities to D. magna and relevant molecular descriptors.

  20. Acute toxicity of fire-retardant and foam-suppressant chemicals to yalella azteca (Saussure)

    USGS Publications Warehouse

    McDonald, Susan F.; Hamilton, Steven J.; Buhl, Kevin J.; Heisinger, James F.

    1997-01-01

    Acute toxicity tests were conducted with Hyalella azteca Saussure (an amphipod) exposed in soft and hard waters to three fire retardants (Fire-Trol GTS-R, Fire-Trol LCG-R, and Phos-Chek D75-F) and two foam suppressants (Phos-Chek WD-881 and Silv-Ex). The chemicals were slightly to moderately toxic to amphipods. The most toxic chemical to amphipods in soft and hard water was Phos-Chek WD-881 (96-h mean lethal concentration [LC50] equal to 10 mg/L and 22 mg/L, respectively), and the least toxic chemical to amphipods in soft water was Fire-Trol GTS-R (96-h LC50 equal to 127 mg/L) and in hard water was Fire-Trol LCG-R (96-h LC50 equal to 535 mg/L). Concentrations of ammonia in tests with the three fire retardants and both water types were greater than reported LC50 values and probably were the major toxic component. Estimated un-ionized ammonia concentrations near the LC50 were frequently less than the reported LC50 ammonia concentrations for amphipods. The three fire retardants were more toxic in soft water than in hard water even though ammonia and un-ionized ammonia concentrations were higher in hard water tests than in soft water tests. The accidental entry of fire-fighting chemicals into aquatic environments could adversely affect aquatic invertebrates, thereby disrupting ecosystem function.

  1. Influence of chemical and environmental stressors on acute cadmium toxicity

    SciTech Connect

    Baer, K.N.; Benson, W.H.

    1987-01-01

    Previous investigations have demonstrated that the cytosolic protein metallothionein (MT) is induced not only by exposure to certain heavy metals but also by a variety of other factors, including environmental stress. While MT synthesis has been observed with exposure to cold temperatures, there is a paucity of data concerning the influence of cold on heavy-metal toxicity. The present investigation focused on the influence of metal and cold pretreatments on the acute toxicity of cadmium. Mortalities of 80% and 100% were observed for mice orally administered challenge doses of 100 mg Cd/kg and 150 mg Cd/kg, respectively. To determine a protective cadmium pretreatment dose, animals were administered 2.5, 5, 10, 20, 25, and 50 mg Cd/kg 24 h prior to cadmium challenge. In animals pretreated with 10 mg Cd/kg, mortalities of 20% and 70% were observed with the respective challenge doses. Immediately following cold stress (4/sup 0/C, 12 h), mortalities of 30% and 90% were observed with cadmium challenge doses of 100 and 150 mg Cd/kg, respectively. Significant correlations were demonstrated between induced hepatic MT concentrations and cadmium pretreatment, as well as cold pretreatment. The induced tolerance to cadmium was attributed, in part, to the induction of MT synthesis. Furthermore, the induced levels of MT resulting from cold stress may confound the simplistic approach of using MT as a biological monitor of occupational exposure to cadmium.

  2. Studies on the chemical composition of kohl stone by X-ray diffractometer.

    PubMed

    Ullah, Pervaiz Habib; Mahmood, Zafar Alam; Sualeh, Mohammad; Zoha, S M S

    2010-01-01

    Use of Kohl (Surma) creates toxicity or protects eye, is one of the most controversial topic of modern medicines. However, modern researches show that kohl forms a thin film on the eye lens thus avoiding the direct contract of harmful UV radiation and glare of sun with lens. Black and shining particles of galena in kohl shield the eyes from glare and reflection of sun and thus protect them from harmful effect of UV radiation emerging from the sun. Based on these findings and other properties of kohl, it was decided to undertake this study to ascertain it's chemical composition and to correlate these properties scientifically. In the present study, kohl stone obtained from Madina (Saudi Arabia) was analyzed to ascertain it's chemical composition. The chemical analysis and X-ray diffractometer results obtained, showed that the main component of kohl stone is galena (PbS).

  3. Influence of sediment composition on PAH toxicity using zebrafish (Danio rerio) and Japanese medaka (Oryzias latipes) embryo-larval assays.

    PubMed

    Perrichon, Prescilla; Le Bihanic, Florane; Bustamante, Paco; Le Menach, Karyn; Budzinski, Hélène; Cachot, Jérôme; Cousin, Xavier

    2014-12-01

    Due to hydrophobic and persistent properties, polycyclic aromatic hydrocarbons (PAHs) have a high capacity to accumulate in sediment. Sediment quality criteria, for the assessment of habitat quality and risk for aquatic life, include understanding the fate and effects of PAHs. In the context of European regulation (REACH and Water Framework Directive), the first objective was to assess the influence of sediment composition on the toxicity of two model PAHs, benzo[a]pyrene and fluoranthene using 10-day zebrafish embryo-larval assay. This procedure was undertaken with an artificial sediment in order to limit natural sediment variability. A suitable sediment composition might be then validated for zebrafish and proposed in a new OECD guideline for chemicals testing. Second, a comparative study of toxicity responses from this exposure protocol was then performed using another OECD species, the Japanese medaka. The potential toxicity of both PAHs was assessed through lethal (e.g., survival, hatching success) and sublethal endpoints (e.g., abnormalities, PMR, and EROD) measured at different developmental stages, adapted to the embryonic development time of both species. Regarding effects observed for both species, a suitable artificial sediment composition for PAH toxicity testing was set at 92.5 % dry weight (dw) silica of 0.2-0.5-mm grain size, 5 % dw kaolin clay without organic matter for zebrafish, and 2.5 % dw blond peat in more only for Japanese medaka. PAH bioavailability and toxicity were highly dependent on the fraction of organic matter in sediment and of the K ow coefficients of the tested compounds. The biological responses observed were also dependent of the species under consideration. Japanese medaka embryos appeared more robust than zebrafish embryos for understanding the toxicity of PAHs following a sediment contact test, due to the longer exposure duration and lower sensitivity of sediment physical properties.

  4. Optical disk toxic information online system at Sumitomo Chemical Co. through telecommunication network in Japan

    NASA Astrophysics Data System (ADS)

    Kishida, Fumio; Omodaka, Hisakata; Ishihara, Koichiro; Yamada, Yoshinori; Kato, Hiromi

    Toxicity data about several hundred chemicals, handled and commercialized by Sumitomo Chemical Co., have been collected and estimated. These data are stored in an optical disk filing system "sanfile 8500D". Because the system is mounted with a keyword input panel "Word selecter", information retrieval system is simplified but precised. Online system through telecommunication network is extended between Sumitomo Chemical's works, laboratories, and others. Image informations are mailed from installed facsimili in sanfile 8500D directly.

  5. Essential Oils, Part III: Chemical Composition.

    PubMed

    de Groot, Anton C; Schmidt, Erich

    2016-01-01

    Data on the chemistry of essential oils which have caused contact allergy are provided. The largest group of chemicals found in essential oils consists of terpenes. The number of identified components usually ranges from 100 to 250, but in some oils (lavender, geranium, rosemary) 450 to 500 chemicals have been found. Many chemicals are present in a large number of oils, up to 98% for β-caryophyllene and 97% for limonene. Chemicals that are important constituents of >20 oils are limonene, linalool, and α-pinene. In many essential oils, there are 2 to 5 components which together constitute over 50% to 60% of the oil. In some oils, however, there is one dominant ingredient, making up more than 50% of the oil, including (E)-anethole in aniseed and star anise oil, carvone in spearmint oil, 1,8-cineole (eucalyptol) in Eucalyptus globulus oil, and (E)-cinnamaldehyde in cassia oil. The most important chemicals in 93 individual oils are specified. PMID:27427817

  6. Determination of the Mineral Composition and Toxic Element Contents of Propolis by Near Infrared Spectroscopy.

    PubMed

    González-Martín, M Inmaculada; Escuredo, Olga; Revilla, Isabel; Vivar-Quintana, Ana M; Coello, M Carmen; Riocerezo, Carlos Palacios; Moncada, Guillermo Wells

    2015-11-03

    The potential of near infrared spectroscopy (NIR) with remote reflectance fiber-optic probes for determining the mineral composition of propolis was evaluated. This technology allows direct measurements without prior sample treatment. Ninety one samples of propolis were collected in Chile (Bio-Bio region) and Spain (Castilla-León and Galicia regions). The minerals measured were aluminum, calcium, iron, potassium, magnesium, phosphorus, and some potentially toxic trace elements such as zinc, chromium, nickel, copper and lead. The modified partial least squares (MPLS) regression method was used to develop the NIR calibration model. The determination coefficient (R2) and root mean square error of prediction (RMSEP) obtained for aluminum (0.79, 53), calcium (0.83, 94), iron (0.69, 134) potassium (0.95, 117), magnesium (0.70, 99), phosphorus (0.94, 24) zinc (0.87, 10) chromium (0.48, 0.6) nickel (0.52, 0.7) copper (0.64, 0.9) and lead (0.70, 2) in ppm. The results demonstrated that the capacity for prediction can be considered good for wide ranges of potassium, phosphorus and zinc concentrations, and acceptable for aluminum, calcium, magnesium, iron and lead. This indicated that the NIR method is comparable to chemical methods. The method is of interest in the rapid prediction of potentially toxic elements in propolis before consumption.

  7. Determination of the Mineral Composition and Toxic Element Contents of Propolis by Near Infrared Spectroscopy

    PubMed Central

    González-Martín, M. Inmaculada; Escuredo, Olga; Revilla, Isabel; Vivar-Quintana, Ana M.; Coello, M. Carmen; Palacios Riocerezo, Carlos; Wells Moncada, Guillermo

    2015-01-01

    The potential of near infrared spectroscopy (NIR) with remote reflectance fiber-optic probes for determining the mineral composition of propolis was evaluated. This technology allows direct measurements without prior sample treatment. Ninety one samples of propolis were collected in Chile (Bio-Bio region) and Spain (Castilla-León and Galicia regions). The minerals measured were aluminum, calcium, iron, potassium, magnesium, phosphorus, and some potentially toxic trace elements such as zinc, chromium, nickel, copper and lead. The modified partial least squares (MPLS) regression method was used to develop the NIR calibration model. The determination coefficient (R2) and root mean square error of prediction (RMSEP) obtained for aluminum (0.79, 53), calcium (0.83, 94), iron (0.69, 134) potassium (0.95, 117), magnesium (0.70, 99), phosphorus (0.94, 24) zinc (0.87, 10) chromium (0.48, 0.6) nickel (0.52, 0.7) copper (0.64, 0.9) and lead (0.70, 2) in ppm. The results demonstrated that the capacity for prediction can be considered good for wide ranges of potassium, phosphorus and zinc concentrations, and acceptable for aluminum, calcium, magnesium, iron and lead. This indicated that the NIR method is comparable to chemical methods. The method is of interest in the rapid prediction of potentially toxic elements in propolis before consumption. PMID:26540058

  8. Determination of the Mineral Composition and Toxic Element Contents of Propolis by Near Infrared Spectroscopy.

    PubMed

    González-Martín, M Inmaculada; Escuredo, Olga; Revilla, Isabel; Vivar-Quintana, Ana M; Coello, M Carmen; Riocerezo, Carlos Palacios; Moncada, Guillermo Wells

    2015-01-01

    The potential of near infrared spectroscopy (NIR) with remote reflectance fiber-optic probes for determining the mineral composition of propolis was evaluated. This technology allows direct measurements without prior sample treatment. Ninety one samples of propolis were collected in Chile (Bio-Bio region) and Spain (Castilla-León and Galicia regions). The minerals measured were aluminum, calcium, iron, potassium, magnesium, phosphorus, and some potentially toxic trace elements such as zinc, chromium, nickel, copper and lead. The modified partial least squares (MPLS) regression method was used to develop the NIR calibration model. The determination coefficient (R2) and root mean square error of prediction (RMSEP) obtained for aluminum (0.79, 53), calcium (0.83, 94), iron (0.69, 134) potassium (0.95, 117), magnesium (0.70, 99), phosphorus (0.94, 24) zinc (0.87, 10) chromium (0.48, 0.6) nickel (0.52, 0.7) copper (0.64, 0.9) and lead (0.70, 2) in ppm. The results demonstrated that the capacity for prediction can be considered good for wide ranges of potassium, phosphorus and zinc concentrations, and acceptable for aluminum, calcium, magnesium, iron and lead. This indicated that the NIR method is comparable to chemical methods. The method is of interest in the rapid prediction of potentially toxic elements in propolis before consumption. PMID:26540058

  9. Honey: Chemical composition, stability and authenticity.

    PubMed

    da Silva, Priscila Missio; Gauche, Cony; Gonzaga, Luciano Valdemiro; Costa, Ana Carolina Oliveira; Fett, Roseane

    2016-04-01

    The aim of this review is to describe the chemical characteristics of compounds present in honey, their stability when heated or stored for long periods of time and the parameters of identity and quality. Therefore, the chemical characteristics of these compounds were examined, such as sugars, proteins, amino acids, enzymes, organic acids, vitamins, minerals, phenolic and volatile compounds present in honey. The stability of these compounds in relation to the chemical reactions that occur by heating or prolonged storage were also discussed, with increased understanding of the behavior regarding the common processing of honey that may compromise its quality. In addition, the identity and quality standards were described, such as sugars, moisture, acidity, ash and electrical conductivity, color, 5-HMF and diastase activity, along with the minimum and maximum limits established by the Codex Alimentarius.

  10. Honey: Chemical composition, stability and authenticity.

    PubMed

    da Silva, Priscila Missio; Gauche, Cony; Gonzaga, Luciano Valdemiro; Costa, Ana Carolina Oliveira; Fett, Roseane

    2016-04-01

    The aim of this review is to describe the chemical characteristics of compounds present in honey, their stability when heated or stored for long periods of time and the parameters of identity and quality. Therefore, the chemical characteristics of these compounds were examined, such as sugars, proteins, amino acids, enzymes, organic acids, vitamins, minerals, phenolic and volatile compounds present in honey. The stability of these compounds in relation to the chemical reactions that occur by heating or prolonged storage were also discussed, with increased understanding of the behavior regarding the common processing of honey that may compromise its quality. In addition, the identity and quality standards were described, such as sugars, moisture, acidity, ash and electrical conductivity, color, 5-HMF and diastase activity, along with the minimum and maximum limits established by the Codex Alimentarius. PMID:26593496

  11. Exposure Considerations for Chemical Prioritization and Toxicity Testing

    EPA Science Inventory

    Globally there is a need to characterize potential risk to human health and the environment that arises from the manufacture and use of tens of thousands of chemicals. Currently, a significant research effort is underway to apply new technologies to screen and prioritize chemica...

  12. Molecular Modeling to Predict and Understand Chemical Toxicity

    EPA Science Inventory

    The risk posed to human health and the environment by chemicals that result from human activity often must be evaluated when relevant elements of the preferred data set are unavailable. Therefore, strategies are needed that estimate this information and prioritize the outstanding...

  13. Predicting modes of toxic action from chemical structure

    EPA Science Inventory

    Like many of the papers in the ET&C top 100 list, the development of the fathead minnow database and the assignment of modes of action to the 617 chemicals therein was the result of a comprehensive research effort by a multidisciplinary team of researchers with expertise in quant...

  14. The Toxicity Data Landscape for Environmental Chemicals (journal)

    EPA Science Inventory

    Thousands of chemicals are in common use but only a portion of them have undergone significant toxicological evaluation, leading to the need to prioritize the remainder for targeted testing. To address this issue, the U.S. Environmental Protection Agency (U.S. EPA) and other orga...

  15. Food safety. [chemical contaminants and human toxic diseases

    NASA Technical Reports Server (NTRS)

    Pier, S. M.; Valentine, J. L.

    1975-01-01

    Illness induced by unsafe food is a problem of great public health significance. This study relates exclusively to the occurrence of chemical agents which will result in food unsafe for human consumption since the matter of food safety is of paramount importance in the mission and operation of the manned spacecraft program of the National Aeronautics and Space Administration.

  16. The Virtual Liver: Modeling Chemical-Induced Liver Toxicity

    EPA Science Inventory

    The US EPA Virtual Liver (v-Liver) project is aimed at modeling chemical-induced processes in hepatotoxicity and simulating their dose-dependent perturbations. The v-Liver embodies an emerging field of research in computational tissue modeling that integrates molecular and cellul...

  17. The relationship of argon retentivity and chemical composition of hornblende

    SciTech Connect

    Leake, B.E.; Farrow, C.M. ); Elias, E.M. )

    1988-08-01

    K-Ar ages of 26 hornblende separates from Connemara, western Ireland do not show any correlation with the chemical composition of the hornblendes, including their iron contents. It is suggested that this is the usual pattern as there are only rare reports of compositional control of K-Ar ages.

  18. Contributions regarding chemical composition variation in ultrasonic field overlaying welding

    NASA Astrophysics Data System (ADS)

    Amza, Gh; Petrescu, V.; Niţoi, D. F.; Amza, C. Gh; Dimitrescu, A.; Apostolescu, Z.

    2016-08-01

    Paper presents a new reconditioning method based on ultrasonic field and analyses the modificated structure composition in three zone: filler material, thermal influenced zone, and base material. Also, chemical composition variation as a result of ultrasonic wave influence is studied besides the ultrasonic wave influence on dilution process.

  19. Chemical Equilibrium Composition of Aqueous Systems

    1996-12-30

    MINEQL is a subroutine package to calculate equilibrium composition of an aqueous system, accounting for mass transfer. MINEQL-EIR contains an additional base on enthalpy and heat capacity data and has the option to do calculations at temperatures different from 25 degrees C.

  20. Linear solvation energy relationships for toxicity of selected organic chemicals to Daphnia pulex and Daphnia magna

    USGS Publications Warehouse

    Passino, Dora R.M.; Hickey, James P.; Frank, Anthony M.

    1988-01-01

    In the Laurentian Great Lakes, more than 300 contaminants have been identified in fish, other biota, water, and sediment. Current hazard assessment of these chemicals by the National Fisheries Research Center-Great Lakes is based on their toxicity, occurrence in the environment, and source. Although scientists at the Center have tested over 70 chemicals with the crustacean Daphnia pulex, the number of experimental data needed to screen the huge array of chemicals in the Great Lakes exceeds the practical capabilities of conducting bioassays. This limitation can be partly circumvented, however, by using mathematical models based on quantitative structure-activity relationships (QSAR) to provide rapid, inexpensive estimates of toxicity. Many properties of chemicals, including toxicity, bioaccumulation and water solubility are well correlated and can be predicted by equations of the generalized linear solvation energy relationships (LSER). The equation we used to model solute toxicity is Toxicity = constant + mVI/100 + s (π* + dδ) + bβm + aαm where VI = intrinsic (Van der Waals) molar volume; π* = molecular dipolarity/polarizability; δ = polarizability 'correction term'; βm = solute hydrogen bond acceptor basicity; and αm = solute hydrogen bond donor acidity. The subscript m designates solute monomer values for α and β. We applied the LSER model to 48-h acute toxicity data (measured as immobilization) for six classes of chemicals detected in Great Lakes fish. The following regression was obtained for Daphnia pulex (concentration = μM): log EC50 = 4.86 - 4.35 VI/100; N = 38, r2 = 0.867, sd = 0.403 We also used the LSER modeling approach to analyze to a large published data set of 24-h acute toxicity for Daphnia magna; the following regression resulted, for eight classes of compounds (concentration = mM): log EC50 = 3.88 - 4.52 VI/100 - 1.62 π* + 1.66 βm - 0.916 αm; N = 62, r2 = 0.859, sd = 0.375 In addition we developed computer software that identifies

  1. Comparative Toxicity of Eight Oil Dispersants, Louisiana Sweet Crude Oil (LSC) and Chemically Dispersed LSC to Two Aquatic Test Species

    EPA Science Inventory

    This study describes the acute toxicity of eight commercial oil dispersants, Louisiana sweet crude oil (LSC), and chemically dispersed LSC. The approach utilized consistent test methodologies within a single laboratory in assessing the relative acute toxicity of the eight dispers...

  2. Prediction of acute toxicity of chemicals in mixtures: worms Tubifex tubifex and gas/liquid distribution.

    PubMed

    Tichý, M; Borek-Dohalský, V; Matousová, D; Rucki, M; Feltl, L; Roth, Z

    2002-03-01

    The aim of this contribution is to support our proposal of the procedure for predicting acute toxicity of binary mixtures by QSAR analysis techniques. The changes of a mixture composition are described by molar ratio R and visualized in the R-plot (QCAR--quantitative composition-activity relationships). The approach was inspired by Rault and Dalton's laws, their positive and negative deviations in the behavior of a mixture of real gases, by Loewe and Muischnek isoboles and by the Finney test of additivity. Acute toxicity was determined by the laboratory test with woms Tubifex tubifex. The additivity of the acute toxicity in the binary mixture benzene + nitrobenzene was confirmed and a new interaction is described: "mixed interaction" with the binary mixture aniline + ethanol. The "mixed interaction" means that depending on mixture composition, both potentiation and inhibition can occur. As the first physicochemical descriptor of the changes caused by the changing composition of binary mixtures, the gas/liquid equilibrium was studied and a composition of the gaseous phase was determined by a gas chromatographic method. The method for determination of concentrations in the gaseous phase was described. The gaseous phase composition of benzene + nitrobenzene. benzene + ethanol, benzene + aniline and ethanol + aniline mixtures was analyzed. It was found that if the concentrations of the mixture's components in the gaseous phase behave nonideally (they are not additive), the acute toxicity of the same mixture is not additive as well. Another descriptor to distinguish between potentiation and inhibition will be, however, necessary. The properties, both gaseous phase composition and the acute toxicity, of the benzene + nitrobenzene mixture are additive. In mixtures with the mixed interaction, the R-plot of the composition of the gaseous phase is complex with a large variation of results.

  3. Stabilization of microorganisms for in situ degradation of toxic chemicals

    SciTech Connect

    Crawford, R.L.; Stormo, K.

    1990-01-01

    In our initial work, we have developed methods to microencapsulate cells within beads of 5--100,{mu}m diameter, and we have examined these entrapped cells for their abilities to mineralize specific chemicals in the presence of subsurface soils and waters obtained from the University of Idaho Groundwater Research Site (GRS). We have employed a pentachlorophenol (PCP)-degrading Flavobacterium and a toluene-degrading Pseudomonas. Cells were immobilized within one of three polymeric matrixes: alginate, agarose, or polyurethane.

  4. Toxicity of pentachlorophenol to six species of white rot fungi as a function of chemical dose

    SciTech Connect

    Alleman, B.C. ); Logan, B.E.; Gilbertson, R.L. )

    1992-12-01

    White rot fungi degrade a wide variety of environmental pollutants including many chlorinated aromatic compounds, leading to studies of degrading organic pollutants in contaminated waste waters and soils. This study looks at six species of white rot fungus and demonstrates that chemical toxicity should be expressed in terms of dose by examining the toxic effects of pentachlorophenol (PCP) on both developing and mature fungal mats in stationary liquid cultures, under both nitrogen-sufficient and -deficient conditions.

  5. Direct chemical oxidation of mixed or toxic wastes

    SciTech Connect

    Balazs, G B; Cooper, J F; Farmer, J C; Lewis, P

    1999-05-01

    Direct Chemical Oxidation (DCO) is an ambient-pressure, low-temperature (<100 C), and aqueous-based process for general-purpose destruction of the organic fraction of hazardous or mixed waste. It uses the peroxydisulfate anion (S{sub 2}O{sub 8}{sup 2{minus}}) in acid or base solutions. The byproduct of the oxidation reaction, typically sodium or ammonium hydrogen sulfate, may be recycled electrolytically to produce the oxidant. The oxidation kinetic reaction is first order with respect to the peroxydisulfate concentration, expressed in equivalents. The rate constant is constant for nearly all dissolved organic compounds: k{sub a} = 0.01 {+-} 0.005 min{sup {minus}1}. This reflects a common rate-determining step, which is the decomposition of the peroxydisulfate anion into the chemically active derivative, the sulfate radical anion, SO{sub 4}{sup {minus}}. This decomposition is promoted in DCO by raising the operating temperature into the range of 80-100 C. Rates are given for approximately 30 substances with diverse functional groups at low concentrations, and for a number of solid and liquid wastes typical of nuclear and chemical industries. The process has been scale up for treatment studies on chlorinated hydrocarbons, in which the hydrolysis of solvent mixtures was followed by oxidation of products in a series of stirred tank reactors. Cost estimates, safety considerations, and a comprehensive bibliography are given.

  6. Effective Strategies for Monitoring and Regulating Chemical Mixtures and Contaminants Sharing Pathways of Toxicity

    PubMed Central

    Venkatesan, Arjun K.; Halden, Rolf U.

    2015-01-01

    Traditionally, hazardous chemicals have been regulated in the U.S. on a one-by-one basis, an approach that is slow, expensive and can be inefficient, as illustrated by a decades-long succession of replacing one type of organohalogen flame retardants (OHFRs) with another one, without addressing the root cause of toxicity and associated public health threats posed. The present article expounds on the need for efficient monitoring strategies and pragmatic steps in reducing environmental pollution and adverse human health impacts. A promising approach is to combine specific bioassays with state-of-the-art chemical screening to identify chemicals and chemical mixtures sharing specific modes of action (MOAs) and pathways of toxicity (PoTs). This approach could be used to identify and regulate hazardous chemicals as classes or compound families, featuring similar biological end-points, such as endocrine disruption and mutagenicity. Opportunities and potential obstacles of implementing this approach are discussed. PMID:26343697

  7. Chemical composition of Earth, Venus, and Mercury.

    PubMed

    Morgan, J W; Anders, E

    1980-12-01

    Model compositions of Earth, Venus, and Mercury are calculated from the premise that planets and chondrites underwent four identical fractionation processes in the solar nebula. Because elements of similar properties stay together in these processes, five constraints suffice to define the composition of a planet: mass of the core, abundance of U, and the ratios K/U, Tl/U, and FeO/(FeO + MgO). Complete abundance tables, and normative mineralogies, are given for all three planets. Review of available data shows only a few gross trends for the inner planets: FeO decreases with heliocentric distance, whereas volatiles are depleted and refractories are enriched in the smaller planets.

  8. Chemical composition of Earth, Venus, and Mercury.

    PubMed

    Morgan, J W; Anders, E

    1980-12-01

    Model compositions of Earth, Venus, and Mercury are calculated from the premise that planets and chondrites underwent four identical fractionation processes in the solar nebula. Because elements of similar properties stay together in these processes, five constraints suffice to define the composition of a planet: mass of the core, abundance of U, and the ratios K/U, Tl/U, and FeO/(FeO + MgO). Complete abundance tables, and normative mineralogies, are given for all three planets. Review of available data shows only a few gross trends for the inner planets: FeO decreases with heliocentric distance, whereas volatiles are depleted and refractories are enriched in the smaller planets. PMID:16592930

  9. Acute oral toxicity of chemicals in terrestrial life stages of amphibians: Comparisons to birds and mammals.

    PubMed

    Crane, Mark; Finnegan, Meaghean; Weltje, Lennart; Kosmala-Grzechnik, Sylwia; Gross, Melanie; Wheeler, James R

    2016-10-01

    Amphibians are currently the most threatened and rapidly declining group of vertebrates and this has raised concerns about their potential sensitivity and exposure to plant protection products and other chemicals. Current environmental risk assessment procedures rely on surrogate species (e.g. fish and birds) to cover the risk to aquatic and terrestrial life stages of amphibians, respectively. Whilst a recent meta-analysis has shown that in most cases amphibian aquatic life stages are less sensitive to chemicals than fish, little research has been conducted on the comparative sensitivity of terrestrial amphibian life stages. Therefore, in this paper we address the questions "What is the relative sensitivity of terrestrial amphibian life stages to acute chemical oral exposure when compared with mammals and birds?" and "Are there correlations between oral toxicity data for amphibians and data for mammals or birds?" Identifying a relationship between these data may help to avoid additional vertebrate testing. Acute oral amphibian toxicity data collected from the scientific literature and ecotoxicological databases were compared with toxicity data for mammals and birds. Toxicity data for terrestrial amphibian life stages are generally sparse, as noted in previous reviews. Single-dose oral toxicity data for terrestrial amphibian life stages were available for 26 chemicals and these were positively correlated with LD50 values for mammals, while no correlation was found for birds. Further, the data suggest that oral toxicity to terrestrial amphibian life stages is similar to or lower than that for mammals and birds, with a few exceptions. Thus, mammals or birds are considered adequate toxicity surrogates for use in the assessment of the oral exposure route in amphibians. However, there is a need for further data on a wider range of chemicals to explore the wider applicability of the current analyses and recommendations.

  10. Linking algal growth inhibition to chemical activity: baseline toxicity required 1% of saturation.

    PubMed

    Schmidt, Stine N; Mayer, Philipp

    2015-02-01

    Recently, high-quality data were published on the algal growth inhibition caused by 50 non-polar narcotic compounds, of which 39 were liquid compounds with defined water solubility. In the present study, the toxicity data for these liquids were applied to challenge the chemical activity range for baseline toxicity. First, the reported effective concentrations (EC50) were divided by the respective water solubilities (S water), since the obtained EC50/S water ratio essentially equals the effective chemical activity (Ea50). The majority of EC50/S water ratios were within the expected chemical activity range of 0.01-0.1 for baseline toxicity, and none of the ratios were significantly below 0.01. On a practical level, these findings suggest EC50 values for baseline toxicity to be at or above 1% of liquid solubility, which would have been accurate or conservative for all 39 liquids with defined water solubility in the applied dataset. On an environmental risk assessment level, predicted no-effect concentrations (PNECs) for baseline toxicity could even be set as a percentage of saturation, which can easily be extended to mixtures. However, EC50 values well below 1% of liquid saturation can still occur and would be a direct indication of excess toxicity.

  11. The U.S. Environmental Protection Agency strategic plan for evaluating the toxicity of chemicals.

    PubMed

    Firestone, Michael; Kavlock, Robert; Zenick, Hal; Kramer, Melissa

    2010-02-01

    In the 2007 report Toxicity Testing in the 21st Century: A Vision and a Strategy, the U.S. National Academy of Sciences envisioned a major transition in toxicity testing from cumbersome, expensive, and lengthy in vivo testing with qualitative endpoints, to in vitro robotic high-throughput screening with mechanistic quantitative parameters. Recognizing the need for agencies to partner and collaborate to ensure global harmonization, standardization, quality control and information sharing, the U.S. Environmental Protection Agency is leading by example and has established an intra-agency Future of Toxicity Testing Workgroup (FTTW). This workgroup has produced an ambitious blueprint for incorporating this new scientific paradigm to change the way chemicals are screened and evaluated for toxicity. Four main components of this strategy are discussed, as follows: (1) the impact and benefits of various types of regulatory activities, (2) chemical screening and prioritization, (3) toxicity pathway-based risk assessment, and (4) institutional transition. The new paradigm is predicated on the discovery of molecular perturbation pathways at the in vitro level that predict adverse health effects from xenobiotics exposure, and then extrapolating those events to the tissue, organ, or whole organisms by computational models. Research on these pathways will be integrated and compiled using the latest technology with the cooperation of global agencies, industry, and other stakeholders. The net result will be that chemical toxicity screening will become more efficient and cost-effective, include real-world exposure assessments, and eliminate currently used uncertainty factors.

  12. Dissecting the assays to assess microbial tolerance to toxic chemicals in bioprocessing.

    PubMed

    Zingaro, Kyle A; Nicolaou, Sergios A; Papoutsakis, Eleftherios T

    2013-11-01

    Microbial strains are increasingly used for the industrial production of chemicals and biofuels, but the toxicity of components in the feedstock and product streams limits process outputs. Selected or engineered microbes that thrive in the presence of toxic chemicals can be assessed using tolerance assays. Such assays must reasonably represent the conditions the cells will experience during the intended process and measure the appropriate physiological trait for the desired application. We review currently used tolerance assays, and examine the many parameters that affect assay outcomes. We identify and suggest the use of the best-suited assays for each industrial bioreactor operating condition, discuss next-generation assays, and propose a standardized approach for using assays to examine tolerance to toxic chemicals.

  13. Influence of sediment composition on apparent toxicity in a solid-phase test using bioluminescent bacteria

    SciTech Connect

    Benton, M.J.; Malott, M.L. |; Knight, S.S.; Cooper, C.M.; Benson, W.H.

    1995-03-01

    Clean and spiked sediment formulations of various silt:sand and clay:sand ratios were tested for toxicity using a bioassay that utilizes bioluminescent bacteria. Measured toxicities of clean and copper sulfate-spiked sediments were negatively but nonlinearly related with percent silt and percent clay, but no significant relationship existed between measured toxicity and sediment composition for methyl parathion-spiked formulations. Results suggest that solid-phase sediment bioassays using bioluminescence bacteria may be useful for testing the toxicities of single contaminants in formulated artificial sediments of known particle-size composition, and for repeated samples collected from the same site. However, extreme caution must be taken when testing sediments of varying composition or which may be differentially contaminated or contain a suite of contaminants.

  14. Multispecies QSAR modeling for predicting the aquatic toxicity of diverse organic chemicals for regulatory toxicology.

    PubMed

    Singh, Kunwar P; Gupta, Shikha; Kumar, Anuj; Mohan, Dinesh

    2014-05-19

    The research aims to develop multispecies quantitative structure-activity relationships (QSARs) modeling tools capable of predicting the acute toxicity of diverse chemicals in various Organization for Economic Co-operation and Development (OECD) recommended test species of different trophic levels for regulatory toxicology. Accordingly, the ensemble learning (EL) approach based classification and regression QSAR models, such as decision treeboost (DTB) and decision tree forest (DTF) implementing stochastic gradient boosting and bagging algorithms were developed using the algae (P. subcapitata) experimental toxicity data for chemicals. The EL-QSAR models were successfully applied to predict toxicities of wide groups of chemicals in other test species including algae (S. obliguue), daphnia, fish, and bacteria. Structural diversity of the selected chemicals and those of the end-point toxicity data of five different test species were tested using the Tanimoto similarity index and Kruskal-Wallis (K-W) statistics. Predictive and generalization abilities of the constructed QSAR models were compared using statistical parameters. The developed QSAR models (DTB and DTF) yielded a considerably high classification accuracy in complete data of model building (algae) species (97.82%, 99.01%) and ranged between 92.50%-94.26% and 92.14%-94.12% in four test species, respectively, whereas regression QSAR models (DTB and DTF) rendered high correlation (R(2)) between the measured and model predicted toxicity end-point values and low mean-squared error in model building (algae) species (0.918, 0.15; 0.905, 0.21) and ranged between 0.575 and 0.672, 0.18-0.51 and 0.605-0.689 and 0.20-0.45 in four different test species. The developed QSAR models exhibited good predictive and generalization abilities in different test species of varied trophic levels and can be used for predicting the toxicities of new chemicals for screening and prioritization of chemicals for regulation.

  15. Multispecies QSAR modeling for predicting the aquatic toxicity of diverse organic chemicals for regulatory toxicology.

    PubMed

    Singh, Kunwar P; Gupta, Shikha; Kumar, Anuj; Mohan, Dinesh

    2014-05-19

    The research aims to develop multispecies quantitative structure-activity relationships (QSARs) modeling tools capable of predicting the acute toxicity of diverse chemicals in various Organization for Economic Co-operation and Development (OECD) recommended test species of different trophic levels for regulatory toxicology. Accordingly, the ensemble learning (EL) approach based classification and regression QSAR models, such as decision treeboost (DTB) and decision tree forest (DTF) implementing stochastic gradient boosting and bagging algorithms were developed using the algae (P. subcapitata) experimental toxicity data for chemicals. The EL-QSAR models were successfully applied to predict toxicities of wide groups of chemicals in other test species including algae (S. obliguue), daphnia, fish, and bacteria. Structural diversity of the selected chemicals and those of the end-point toxicity data of five different test species were tested using the Tanimoto similarity index and Kruskal-Wallis (K-W) statistics. Predictive and generalization abilities of the constructed QSAR models were compared using statistical parameters. The developed QSAR models (DTB and DTF) yielded a considerably high classification accuracy in complete data of model building (algae) species (97.82%, 99.01%) and ranged between 92.50%-94.26% and 92.14%-94.12% in four test species, respectively, whereas regression QSAR models (DTB and DTF) rendered high correlation (R(2)) between the measured and model predicted toxicity end-point values and low mean-squared error in model building (algae) species (0.918, 0.15; 0.905, 0.21) and ranged between 0.575 and 0.672, 0.18-0.51 and 0.605-0.689 and 0.20-0.45 in four different test species. The developed QSAR models exhibited good predictive and generalization abilities in different test species of varied trophic levels and can be used for predicting the toxicities of new chemicals for screening and prioritization of chemicals for regulation. PMID:24738471

  16. Composition and Toxicity of Biodiesel versus Conventional Diesel

    EPA Science Inventory

    Increasing production of biodiesel (BD) fuel at the local, national, and global levels raise important issues related to the impact and potential adverse health outcome related to BD exposures. Studies on the toxicity of BD combustion emissions are very limited. Emission co...

  17. Essential Oil from Flowers and Leaves of Elaeagnus Angustifolia (Elaeagnaceae): Composition, Radical Scavenging and General Toxicity Activities

    PubMed Central

    Torbati, Mohammadali; Asnaashari, Solmaz; Heshmati Afshar, Fariba

    2016-01-01

    Purpose: The aim of this work was to identify the chemical composition of the essential oils obtained from the flowers and leaves of Elaeagnus angostifolia (Elaeagnaceae) along with evaluate the radical scavenging and general toxicity activities. Methods: A combination of GC-MS and GC-FID were utilized for analyzing the chemical profile of the essential oils extracted by hydro-distillation from the leaves and flowers of E. angustifolia. The essential oils were subjected to general toxicity and radical scavenging assays using brine shrimp lethality test and DPPH method, respectively. Results: In total, 53 and 25 components were identified and quantified in the essential oils of flowers and leaves, accounting for 96.59% and 98.97% of the oil, respectively. The both oils were observed to be rich in ester compounds. The most abundant components of the oil from flowers were E-ethyl cinnamate (60.00%), hexahydrofarnesyl acetone (9.99%), palmitic acid (5.20%) and phytol (3.29%). The major constituents of the oil from leaves were E-ethyl cinnamate (37.27%), phytol (12.08%), nonanal (10.74%) and Z-3-hexenyl benzoate (7.65%). Both oils showed moderate activity in DPPH assay; however, they exhibited potent tocixity in brine shrimp lethality test. Conclusion: The remarkable toxicity effects of the oils are worthy to further investigation to find the probable mechanisms of action accountable for the noticeable toxic effect of these essential oils. PMID:27478777

  18. Development and evaluation of multispecies test protocols for assessing chemical toxicity

    SciTech Connect

    Garten, C.T. Jr.; Suter, G.W. II; Blaylock, B.G.

    1985-06-01

    Toxicity testing is a well-recognized tool to assist in evaluating the hazards of chemicals to individual biological species. Multispecies toxicity tests, however, are now well developed. Three test systems were examined: the legume-Rhizobium symbiosis for N-fixation, soil microbial populations, and algal multispecies interactions. Test protocols were to be developed and tested using several different chemicals. Test protocols for the legume-Rhizobium and soil microorganisms systems were developed and are presented. The algal multispecies system will require more research, and thus no protocol was recommended at this time. Separate abstracts were prepared for each test system. (ACR)

  19. 1997 toxic chemical release inventory -- Emergency Planning and Community Right-To-Know Act, Section 313

    SciTech Connect

    Zaloudek, D.E.

    1998-06-30

    Two listed toxic chemicals were used at the Hanford Site above established activity thresholds: phosphoric acid and chlorine. Because total combined quantities of chlorine released, disposed, treated, recovered through recycle operations, co-combusted for energy recovery, and transferred to off-site locations for the purpose of recycle, energy recovery, treatment, and/or disposal, amounted to less than 500 pounds, the Hanford Site qualified for the alternate one million pound threshold for chlorine. Accordingly, this Toxic Chemical Release Inventory includes a Form A for chlorine, and a Form B for phosphoric acid.

  20. Selected chemical characteristics and acute toxicity of urban stormwater, streamflow, and bed material, Maricopa County, Arizona

    USGS Publications Warehouse

    Lopes, T.J.; Fossum, K.D.

    1995-01-01

    Statistical analyses indicated that urban stormwater could degrade the quality of streamflow because of oil and grease, pesticides, dissolved trace metals, and ammonia in stormwater. Ammonia, lead, cadmium, and zinc are released by urban activities and accumulate in bed material. Ammonia could be from fertilizers, fecal matter, and other sources. Lead is probably from vehicles that use leaded gasoline. Cadmium and zinc could be from particulate metal in oil, brake pads, and other sources. Samples of the initial runoff from urban drainage basins appeared to be more toxic than flow-weighted composite samples, and stormwater was more harmful to fathead minnows than to Ceriodaphnia dubia. Streamflow samples from the Salt River were not toxic to either species. The sensitivity of fathead minnows to urban stormwater from most urban drainage basins indicated that the toxicants were detrimental to fish and could be present in stormwater throughout Phoenix. Results of toxicity identification evaluations indicated the toxicity was mostly due to organic constituents. Mortality, however, did not correlate with organophosphate pesticide concentrations. Surfactants and (or) other constituents leached from asphalt could be toxic. The most toxic bed-material samples were collected from an undeveloped drainage basin. Within urban-drainage basins, bed-material samples collected where stormwater accumulates appeared to be more toxic than samples collected from areas unaffected by stormwater. Mortality rates correlated with recoverable concentrations of zinc, copper, and cadmium; however these rates correlated poorly with pesticide concentrations. The bioavailability of trace metals appeared to be controlled by the adsorption properties of bed material.

  1. The chemical composition of interstellar molecular clouds

    NASA Technical Reports Server (NTRS)

    Irvine, W. M.; Hjalmarson, A.

    1984-01-01

    Quantitative molecular abundances are becoming available for dense interstellar clouds and circumstellar envelopes, revealing both similarities across a wide range of source conditions and significant differences in the chemistries involved. As understanding concerning the processes that lead to particular compositions increases, it may become possible to relate these findings to the evolution of molecular clouds and hence to the chemistry of regions in which stellar and planetary formation is in progress. Attention is given to the results of a recently completed spectral scan of the Orion molecular cloud, as well as the envelope around the evolved star IRC + 10216, published by Johansson et al. (1983).

  2. Chemical Composition of Icy Satellite Surfaces

    NASA Astrophysics Data System (ADS)

    Dalton, J. B.; Cruikshank, D. P.; Stephan, K.; McCord, T. B.; Coustenis, A.; Carlson, R. W.; Coradini, A.

    2010-06-01

    Much of our knowledge of planetary surface composition is derived from remote sensing over the ultraviolet through infrared wavelength ranges. Telescopic observations and, in the past few decades, spacecraft mission observations have led to the discovery of many surface materials, from rock-forming minerals to water ice to exotic volatiles and organic compounds. Identifying surface materials and mapping their distributions allows us to constrain interior processes such as cryovolcanism and aqueous geochemistry. The recent progress in understanding of icy satellite surface composition has been aided by the evolving capabilities of spacecraft missions, advances in detector technology, and laboratory studies of candidate surface compounds. Pioneers 10 and 11, Voyagers I and II, Galileo, Cassini and the New Horizons mission have all made significant contributions. Dalton (Space Sci. Rev., 2010, this issue) summarizes the major constituents found or inferred to exist on the surfaces of the icy satellites (cf. Table 1 from Dalton, Space Sci. Rev., 2010, this issue), and the spectral coverage and resolution of many of the spacecraft instruments that have revolutionized our understanding (cf. Table 2 from Dalton, Space Sci. Rev., 2010, this issue). While much has been gained from these missions, telescopic observations also continue to provide important constraints on surface compositions, especially for those bodies that have not yet been visited by spacecraft, such as Kuiper Belt Objects (KBOs), trans-Neptunian Objects (TNOs), Centaurs, the classical planet Pluto and its moon, Charon. In this chapter, we will discuss the major satellites of the outer solar system, the materials believed to make up their surfaces, and the history of some of these discoveries. Formation scenarios and subsequent evolution will be described, with particular attention to the processes that drive surface chemistry and exchange with interiors. Major similarities and differences between the

  3. Chemical composition of plasma treated polyimide microspheres

    NASA Astrophysics Data System (ADS)

    Gawdzik, Barbara; Sobiesiak, Magdalena

    2003-05-01

    Synthetic carbon microspheres for chromatography were obtained from porous copolymer of 4,4'-bis(maleimidodiphenyl)methane (BM) and divinylbenzene (DVB) using arc discharge argon plasma treatment. Chemical structure of the obtained material was determined by elemental analysis, scanning electron microscopy with X-ray detector, acid and base titrations, and atomic absorption spectroscopy. The results suggest that the carbon microspheres contain copper coming from the plasma reactor electrodes. To remove it two complexion agents were used: EDTA and 20% HNO 3. Copper can be removed from the surface using these methods. The other amount was permanently built into internal structure of the microspheres.

  4. Energetic composites and method of providing chemical energy

    DOEpatents

    Danen, Wayne C.; Martin, Joe A.

    1997-01-01

    A method for providing chemical energy and energetic compositions of matter consisting of thin layers of substances which will exothermically react with one another. The layers of reactive substances are separated by thin layers of a buffer material which prevents the reactions from taking place until the desired time. The reactions are triggered by an external agent, such as mechanical stress or an electric spark. The compositions are known as metastable interstitial composites (MICs). This class of compositions includes materials which have not previously been capable of use as energetic materials. The speed and products of the reactions can be varied to suit the application.

  5. Energetic composites and method of providing chemical energy

    DOEpatents

    Danen, W.C.; Martin, J.A.

    1997-02-25

    A method is described for providing chemical energy and energetic compositions of matter consisting of thin layers of substances which will exothermically react with one another. The layers of reactive substances are separated by thin layers of a buffer material which prevents the reactions from taking place until the desired time. The reactions are triggered by an external agent, such as mechanical stress or an electric spark. The compositions are known as metastable interstitial composites (MICs). This class of compositions includes materials which have not previously been capable of use as energetic materials. The speed and products of the reactions can be varied to suit the application. 3 figs.

  6. Toxic organic chemicals in waste streams: anaerobic bioconversion to methane

    SciTech Connect

    Young, L.Y.

    1985-01-01

    Sixteen substituted aromatic compounds were evaluated for their anaerobic biodegradability and toxicity to methanogenesis with two standardized anaerobic bioassays. Each compound was the only added carbon source (20 to 200 mg/L) prepared in prereduced defined medium with a 10% (v/v) inoculum of municiple digester sludge. Four types of responses were observed: (1) all concentrations of benzoate, phenol, dibutyl phthalate and low concentrations (20 mg/L) of dimethyl and diethyl phthalate, 4-nitrophenol and 2,4-dinitrophenol were degraded to CH/sub 4/ and CO/sub 2/, attaining 50-100% of the theoretical gas yield; (2) high concentrations (200 mg/L) of diethyl and dimethyl phthalate, and low concentrations of 2-nitrophenol produced methane yields between 10 to 50% of the theoretical; (3) all concentrations of bis(2-ethylhexyl)phthalate, 2,4-dimethyl phenol, 4-chloro-m-cresol, ortho- and meta-cresol, 2-chlorophenol, intermediate concentrations (100 mg/L) of 2-nitrophenol and low concentrations of 4,6-dinitro-o-cresol yielded no more than 10% of the theoretical methane value; (4) high concentrations of 2-nitrophenol, 4-nitrophenol, 4,6-dinitro-o-cresol and 2,4-dinitrophenol exhibited a distinct suppression of methanogenesis from 10 to 90% below that of the background. Acclimation for most of the compounds took several days to weeks before degradation commenced. Thus, many of these compounds are metabolized in anoxic environments. Their fate may be significantly influenced by their concentration and residence time in such habitats. 35 refs., 33 figs., 12 tabs.

  7. Chemical degradation and toxicity reduction of 4-chlorophenol in different matrices by gamma-ray treatment

    NASA Astrophysics Data System (ADS)

    Kang, Sung-Wook; Shim, Seung-Bo; Park, Young-Kwon; Jung, Jinho

    2011-03-01

    Gamma-ray treatment of 4-chlorophenol (4-CP) in different matrices was studied in terms of both chemical degradation and toxicity reduction. Degradation of 4-CP in a complex effluent matrix was less efficient than that in ultrapure water. This is most likely due to the consumption of reactive radicals by matrix components, such as dissolved organic matter in effluents. The matrix effect caused much more profound changes in toxicity. Gamma-ray treatment of 4-CP in ultrapure water abruptly increased acute toxicity toward Daphnia magna while slightly decreased toxicity of 4-CP in effluent. In the presence of ZrO 2 catalyst, degradation of 4-CP as well as toxicity reduction was substantially improved mostly by adsorption of 4-CP onto the nanoparticles. It was found that benzoquinone, hydroquinone and 4-chlorocatechol were generated for ultrapure water sample while only 4-chlorocatechol was formed for effluent samples by gamma-ray treatment. As determined in this work, EC 50 values of benzoquinone (0.46 μM), hydroquinone (0.61 μM) and chlorocatechol (8.87 μM) were much lower than those of 4-CP (31.50 μM), explaining different toxicity changes of 4-CP in different matrices by gamma-ray treatment. The observed toxicity of gamma-ray treated 4-CP was well correlated with the one calculated from individual toxicity based on EC 50 value.

  8. Molecular modeling for screening environmental chemicals for estrogenicity: use of the toxicant-target approach.

    PubMed

    Rabinowitz, James R; Little, Stephen B; Laws, Susan C; Goldsmith, Michael-Rock

    2009-09-01

    There is a paucity of relevant experimental information available for the evaluation of the potential health and environmental effects of many man made chemicals. Knowledge of the potential pathways for activity provides a rational basis for the extrapolations inherent in the preliminary evaluation of risk and the establishment of priorities for obtaining missing data for environmental chemicals. The differential step in many mechanisms of toxicity may be generalized as the interaction between a small molecule (a potential toxicant) and one or more macromolecular targets. An approach based on computation of the interaction between a potential molecular toxicant and a library of macromolecular targets of toxicity has been proposed for preliminary chemical screening. In the current study, the interaction between a series of environmentally relevant chemicals and models of the rat estrogen receptors (ER) was computed and the results compared to an experimental data set of their relative binding affinities. The experimental data set consists of 281 chemicals, selected from the U.S. EPA's Toxic Substances Control Act (TSCA) inventory, that were initially screened using the rat uterine cytosolic ER-competitive binding assay. Secondary analysis, using Lineweaver-Burk plots and slope replots, was applied to confirm that only 15 of these test chemicals were true competitive inhibitors of ER binding with experimental inhibition constants (K(i)) less than 100 microM. Two different rapid computational docking methods have been applied. Each provides a score that is a surrogate for the strength of the interaction between each ligand-receptor pair. Using the score that indicates the strongest interaction for each pair, without consideration of the geometry of binding between the toxicant and the target, all of the active molecules were discovered in the first 16% of the chemicals. When a filter is applied on the basis of the geometry of a simplified pharmacophore for binding to

  9. Molecular modeling for screening environmental chemicals for estrogenicity: use of the toxicant-target approach.

    PubMed

    Rabinowitz, James R; Little, Stephen B; Laws, Susan C; Goldsmith, Michael-Rock

    2009-09-01

    There is a paucity of relevant experimental information available for the evaluation of the potential health and environmental effects of many man made chemicals. Knowledge of the potential pathways for activity provides a rational basis for the extrapolations inherent in the preliminary evaluation of risk and the establishment of priorities for obtaining missing data for environmental chemicals. The differential step in many mechanisms of toxicity may be generalized as the interaction between a small molecule (a potential toxicant) and one or more macromolecular targets. An approach based on computation of the interaction between a potential molecular toxicant and a library of macromolecular targets of toxicity has been proposed for preliminary chemical screening. In the current study, the interaction between a series of environmentally relevant chemicals and models of the rat estrogen receptors (ER) was computed and the results compared to an experimental data set of their relative binding affinities. The experimental data set consists of 281 chemicals, selected from the U.S. EPA's Toxic Substances Control Act (TSCA) inventory, that were initially screened using the rat uterine cytosolic ER-competitive binding assay. Secondary analysis, using Lineweaver-Burk plots and slope replots, was applied to confirm that only 15 of these test chemicals were true competitive inhibitors of ER binding with experimental inhibition constants (K(i)) less than 100 microM. Two different rapid computational docking methods have been applied. Each provides a score that is a surrogate for the strength of the interaction between each ligand-receptor pair. Using the score that indicates the strongest interaction for each pair, without consideration of the geometry of binding between the toxicant and the target, all of the active molecules were discovered in the first 16% of the chemicals. When a filter is applied on the basis of the geometry of a simplified pharmacophore for binding to

  10. Quantitative structure-activity relationships for chemical toxicity to environmental bacteria

    SciTech Connect

    Blum, D.J.; Speece, R.E. )

    1991-10-01

    Quantitative structure-activity relationships (QSARs) were developed for nonreactive chemical toxicity to each of four groups of bacteria of importance in environmental engineering: aerobic heterotrophs, methanogens, Nitrosomonas, and Microtox. The QSARs were based on chemicals covering a range of structures and including important environmental pollutants (i.e., chlorinated and other substituted benzenes, phenols, and aliphatic hydrocarbons). QSARs were developed for each chemical class and for combinations of chemical classes. Three QSAR methods (groups of chemical describing parameters) were evaluated for their accuracy and ease of use: log P, linear solvation energy relationships (LSER), and molecular connectivity. Successful QSARs were found for each group of bacteria and by each method, with correlation coefficients (adjusted r2) between 0.79 and 0.95. LSER QSARs incorporated the widest range of chemicals with the greatest accuracy. Log P and molecular connectivity QSARs are easier to use because their parameters are readily available. Outliers from the QSARs likely due to reactive toxicity included acryls, low pKa compounds, and aldehydes. Nitro compounds and chlorinated aliphatic hydrocarbons and alcohols showed enhanced toxicity to the methanogens only. Chemicals with low IC50 concentrations (log IC50 mumol/liter less than 1.5) were often outliers for Nitrosomonas. QSARs were validated statistically and with literature data. A suggested method is provided for use of the QSARs.

  11. Lung Toxicity of Ambient Particulate Matter from Southeastern U.S. Sites with Different Contributing Sources: Relationships between Composition and Effects

    PubMed Central

    Seagrave, JeanClare; McDonald, Jacob D.; Bedrick, Edward; Edgerton, Eric S.; Gigliotti, Andrew P.; Jansen, John J.; Ke, Lin; Naeher, Luke P.; Seilkop, Steven K.; Zheng, Mei; Mauderly, Joe L.

    2006-01-01

    Background Exposure to air pollution and, more specifically, particulate matter (PM) is associated with adverse health effects. However, the specific PM characteristics responsible for biological effects have not been defined. Objectives In this project we examined the composition, sources, and relative toxicity of samples of PM with aerodynamic diameter ≥2.5 μm (PM2.5) collected from sites within the Southeastern Aerosol Research and Characterization (SEARCH) air monitoring network during two seasons. These sites represent four areas with differing sources of PM2.5, including local urban versus regional sources, urban areas with different contributions of transportation and industrial sources, and a site influenced by Gulf of Mexico weather patterns. Methods We collected samples from each site during the winter and summer of 2004 for toxicity testing and for chemical analysis and chemical mass balance–based source apportionment. We also collected PM2.5 downwind of a series of prescribed forest burns. We assessed the toxicity of the samples by instillation into rat lungs and assessed general toxicity, acute cytotoxicity, and inflammation. Statistical dose–response modeling techniques were used to rank the relative toxicity and compare the seasonal differences at each site. Projection-to-latent-surfaces (PLS) techniques examined the relationships among sources, chemical composition, and toxicologic end points. Results and conclusions Urban sites with high contributions from vehicles and industry were most toxic. PMID:16966093

  12. Certain glycol ethers eliminated from toxic chemical release reporting requirements

    SciTech Connect

    1994-09-01

    Effective June 28, 1994, the U.S. Environmental Protection Agency (EPA) eliminated high molecular weight glycol ethers from the reporting requirements of section 313 of the Emergency Planning and Community Right-To-Know Act of 1986 (EPCRA). EPCRA (42 U.S.C. 11023) is also referred to as Title III of the Superfund Amendments and Reauthorization Act (SARA) of 1986. EPA redefined the glycol ethers category list of chemicals subject to reporting based on an EPA review of available human health data on short-chain glycol ethers. EPA is removing only the surfactant glycol ethers, which are high molecular weight glycol ethers, i.e., those with pendant alkyl groups and that typically have eight or more carbon atoms. The redefinition retains certain glycol ethers (i.e., ethylene glycol ethers where there are 1,2, or 3 repeating ethylene oxide groups) in the category. These are reasonably anticipated to cause adverse human health effects.

  13. Role of renal metabolism in risk to toxic chemicals.

    PubMed Central

    Lash, L H

    1994-01-01

    The kidneys are capable of carrying out extensive oxidation, reduction, hydrolysis, and conjugation reactions. Renal cortex has high activities of cytochrome P450 and glutathione (GSH) S-transferase. In contrast, renal medulla has high activity of prostaglandin synthetase, which can catalyze co-oxidation of xenobiotics. While these pathways are found in many tissues and at higher activities than in kidney, several key enzymes of the mercapturic acid pathway are found at especially high activities in cells of the renal proximal tubule. Investigations over the last two decades demonstrated that GSH conjugation is not only a mechanism for detoxification of reactive electrophiles. Rather, metabolism of GSH S-conjugates to the corresponding cysteine S-conjugates represents a branch point: cysteine S-conjugates may be metabolized by the cysteine S-conjugate N-acetyl-transferase to mercapturic acids, which are nontoxic and are excreted, or they may be substrates for the pyridoxal phosphate-dependent cysteine conjugate beta-lyase, which catalyzes either a beta-elimination or a transamination reaction to produce unstable thiols. These thiols rearrange to form potent acylating species that can covalently bind to cellular macromolecules, thereby producing cytotoxicity, mutagenicity, and carcinogenicity. In addition to the beta-lyase, two other renal enzymes, L-2-amino (2-hydroxy) acid oxidase and cysteine conjugate S-oxidase, can bioactivate chemicals to produce nephrotoxic species. Several halogenated alkanes and alkenes are bioactivated by these pathways. These findings show that mammalian kidney is highly active in bioactivation of xenobiotics. Although the properties of the corresponding enzymes in humans may differ, it is clear that renal metabolism can be a critical determinant of risk to chemical injury. PMID:7737046

  14. Chemical characterization and in vitro toxicity of diesel exhaust particulate matter generated under varying conditions

    PubMed Central

    Cox, David P.; Drury, Bertram E.; Gould, Timothy R.; Kavanagh, Terrance J.; Paulsen, Michael H.; Sheppard, Lianne; Simpson, Christopher D.; Stewart, James A.; Larson, Timothy V.; Kaufman, Joel D.

    2014-01-01

    Epidemiologic studies have linked diesel exhaust (DE) to cardiovascular and respiratory morbidity and mortality, as well as lung cancer. DE composition is known to vary with many factors, although it is unclear how this influences toxicity. We generated eight DE atmospheres by applying a 2×2×2 factorial design and altering three parameters in a controlled exposure facility: (1) engine load (27 vs 82 %), (2) particle aging (residence time ~5 s vs ~5 min prior to particle collection), and (3) oxidation (with or without ozonation during dilution). Selected exposure concentrations of both diesel exhaust particles (DEPs) and DE gases, DEP oxidative reactivity via DTT activity, and in vitro DEP toxicity in murine endothelial cells were measured for each DE atmosphere. Cell toxicity was assessed via measurement of cell proliferation (colony formation assay), cell viability (MTT assay), and wound healing (scratch assay). Differences in DE composition were observed as a function of engine load. The mean 1-nitropyrene concentration was 15 times higher and oxidative reactivity was two times higher for low engine load versus high load. There were no substantial differences in measured toxicity among the three DE exposure parameters. These results indicate that alteration of applied engine load shifts the composition and can modify the biological reactivity of DE. While engine conditions did not affect the selected in vitro toxicity measures, the change in oxidative reactivity suggests that toxicological studies with DE need to take into account engine conditions in characterizing biological effects. PMID:26539254

  15. THE CHEMICAL COMPOSITION OF PRAESEPE (M44)

    SciTech Connect

    Boesgaard, Ann Merchant; Roper, Brian W.; Lum, Michael G. E-mail: brianwroper@gmail.com

    2013-09-20

    Star clusters have long been used to illuminate both stellar evolution and Galactic evolution. They also hold clues to the chemical and nucleosynthetic processes throughout the history of the Galaxy. We have taken high signal-to-noise (S/N), high-resolution spectra of 11 solar-type stars in the Praesepe open cluster to determine the chemical abundances of 16 elements: Li, C, O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe, Ni, Y, and Ba. We have determined Fe from Fe I and Fe II lines and find [Fe/H] = +0.12 ±0.04. We find that Li decreases with temperature due to increasing Li depletion in cooler stars; it matches the Li-temperature pattern found in the Hyades. The [C/Fe] and [O/Fe] abundances are below solar and lower than the field star samples due to the younger age of Praesepe (0.7 Gyr) than the field stars. The alpha-elements, Mg, Si, Ca, and Ti, have solar ratios with respect to Fe, and are also lower than the field star samples. The Fe-peak elements, Cr and Ni, track Fe and have solar values. The neutron capture element [Y/Fe] is found to be solar, but [Ba/Fe] is enhanced relative to solar and to the field stars. Three Praesepe giants were studied by Carrera and Pancino; they are apparently enhanced in Na, Mg, and Ba relative to the Praesepe dwarfs. The Na enhancement may indicate proton-capture nucleosynthesis in the Ne → Na cycling with dredge-up into the atmospheres of the red giants.

  16. Prediction of organ toxicity endpoints by QSAR modeling based on precise chemical-histopathology annotations.

    PubMed

    Myshkin, Eugene; Brennan, Richard; Khasanova, Tatiana; Sitnik, Tatiana; Serebriyskaya, Tatiana; Litvinova, Elena; Guryanov, Alexey; Nikolsky, Yuri; Nikolskaya, Tatiana; Bureeva, Svetlana

    2012-09-01

    The ability to accurately predict the toxicity of drug candidates from their chemical structure is critical for guiding experimental drug discovery toward safer medicines. Under the guidance of the MetaTox consortium (Thomson Reuters, CA, USA), which comprised toxicologists from the pharmaceutical industry and government agencies, we created a comprehensive ontology of toxic pathologies for 19 organs, classifying pathology terms by pathology type and functional organ substructure. By manual annotation of full-text research articles, the ontology was populated with chemical compounds causing specific histopathologies. Annotated compound-toxicity associations defined histologically from rat and mouse experiments were used to build quantitative structure-activity relationship models predicting subcategories of liver and kidney toxicity: liver necrosis, liver relative weight gain, liver lipid accumulation, nephron injury, kidney relative weight gain, and kidney necrosis. All models were validated using two independent test sets and demonstrated overall good performance: initial validation showed 0.80-0.96 sensitivity (correctly predicted toxic compounds) and 0.85-1.00 specificity (correctly predicted non-toxic compounds). Later validation against a test set of compounds newly added to the database in the 2 years following initial model generation showed 75-87% sensitivity and 60-78% specificity. General hepatotoxicity and nephrotoxicity models were less accurate, as expected for more complex endpoints.

  17. Bioconcentration and Aquatic Toxicity of Superhydrophobic Chemicals: A Modeling Case Study of Cyclic Volatile Methyl Siloxanes.

    PubMed

    Mackay, Donald; Powell, David E; Woodburn, Kent B

    2015-10-01

    Many chemicals in commerce are classified as "superhydrophobic", having log octanol-water partition coefficients (log KOW) approaching or exceeding 7. Examples include long-chain alkanes, halogenated aromatics, and cyclic volatile methylsiloxanes (cVMS). We show that superhydrophobic chemicals present unique assessment challenges because of their sparing solubility in water and difficulties in empirical determinations of bioconcentration factors (BCFs) and aquatic toxicity. Using cVMS as an example, BCFs are considerably lower than expected due to biotransformation. Reviewed aquatic toxicity test data for cVMS in a range of aquatic organisms show little or no toxic effects up to solubility limits in water and sediment. Explanations for this apparent lack of toxicity of cVMS, and by extension to other superhydrophobic chemicals, are explored using a conventional one-compartment uptake model to simulate bioconcentration and toxicity tests using an assumed baseline narcotic critical body residue (CBR) and a range of organism sizes. Because of the low aqueous concentrations, equilibration times are very long and BCFs are sensitive to even very slow rates of biotransformation. Most organisms fail to achieve the assumed CBR during feasible test durations even at the solubility limit. Regulatory evaluation of superhydrophobic substances requires specially designed test protocols addressing biotransformation and dietary uptake.

  18. Impact of Environmentally Based Chemical Hardness on Uranium Speciation and Toxicity in Six Aquatic Species

    PubMed Central

    Goulet, Richard R; Thompson, Patsy A; Serben, Kerrie C; Eickhoff, Curtis V

    2015-01-01

    Treated effluent discharge from uranium (U) mines and mills elevates the concentrations of U, calcium (Ca), magnesium (Mg), and sulfate (SO42–) above natural levels in receiving waters. Many investigations on the effect of hardness on U toxicity have been experiments on the combined effects of changes in hardness, pH, and alkalinity, which do not represent water chemistry downstream of U mines and mills. Therefore, more toxicity studies with water chemistry encountered downstream of U mines and mills are necessary to support predictive assessments of impacts of U discharge to the environment. Acute and chronic U toxicity laboratory bioassays were realized with 6 freshwater species in waters of low alkalinity, circumneutral pH, and a range of chemical hardness as found in field samples collected downstream of U mines and mills. In laboratory-tested waters, speciation calculations suggested that free uranyl ion concentrations remained constant despite increasing chemical hardness. When hardness increased while pH remained circumneutral and alkalinity low, U toxicity decreased only to Hyalella azteca and Pseudokirchneriella subcapitata. Also, Ca and Mg did not compete with U for the same uptake sites. The present study confirms that the majority of studies concluding that hardness affected U toxicity were in fact studies in which alkalinity and pH were the stronger influence. The results thus confirm that studies predicting impacts of U downstream of mines and mills should not consider chemical hardness. PMID:25475484

  19. The toxicity of oil and chemically dispersed oil to the seagrass Thalassia testudinum

    SciTech Connect

    Baca, B.J.; Getter, C.D.

    1982-10-01

    Turtle grass beds, a valuable natural resource, are diminishing throughout the tropics because of damage from dredging, boats, and other factors. The toxicity of chemical dispersants and crude oil to turtle grass was determined in the laboratory to assess the potential for damage from spills occurring in the field. Studies of water-soluble fractions (WSF) of crude oil in static bioassays showed that a chemical dispersant (Corexit 9527) increased the amount of total oil in water more than 50-fold. The toxicity of chemically dispersed oil was assessed by conventional (96-h 50% lethal concentration) methods in static systems, and the results were compared with toxicity measurements where the system was flushed after 12 h. Prudhoe Bay crude WSF was more toxic than dispersed oil or dispersant alone, possibly because of the large component of benzene, toluene, and C-2 benzene. The percentage of green (chlorophyllous) leaves was useful as evidence of toxicity. The importance of anatomical features such as recessed meristem and abundant leaf sheaths in protecting the growing region from waterborne pollutants was evident.

  20. Evaluation of bacterial aerotaxis for its potential use in detecting the toxicity of chemicals to microorganisms.

    PubMed

    Shitashiro, Maiko; Kato, Junichi; Fukumura, Tsuyoshi; Kuroda, Akio; Ikeda, Tsukasa; Takiguchi, Noboru; Ohtake, Hisao

    2003-02-27

    Bacterial aerotaxis (the movement of a cell toward oxygen) was evaluated for its potential use in detecting the toxicity of chemicals to microorganisms. The level of toxicity was determined by the concentration of test chemicals resulting in a 50% inhibition of aerotaxis of Pseudomonas aeruginosa PAO1 after 40 min of exposure. The aerotactic responses of P. aeruginosa were measured by using chemotaxis well chambers. Each clear acrylic chamber had a lower and upper well separated by a polycarbonate filter with a uniform pore size of 8.0 microm. To automatically detect bacterial cells that crossed the filter in response to a gradient of oxygen, P. aeruginosa PAO1 was marked with green fluorescent protein (GFP), and the GFP fluorescence intensity in the upper well was continuously monitored by using a fluorescence spectrometer. By using this technique, volatile chlorinated aliphatic compounds, including trichloroethylene (TCE), trichloroethane, and tetrachloroethylene, were found to be inhibitory to bacterial aerotaxis, suggesting their possible toxicity to microorganisms. We also examined more than 20 potential toxicants for their ability to inhibit the aerotaxis of P. aeruginosa. Based on these experimental results, we concluded that bacterial aerotaxis has potential for use as a fast and reliable indicator in assessing the toxicity of chemicals to microorganisms.

  1. Comparison of toxicity of class-based organic chemicals to algae and fish based on discrimination of excess toxicity from baseline level.

    PubMed

    Li, Jin J; Tai, Hong W; Yu, Yang; Wen, Yang; Wang, Xiao H; Zhao, Yuan H

    2015-07-01

    Toxicity data to fish and algae were used to investigate excess toxicity between species. Results show that chemicals exhibiting excess toxicity to fish also show excess toxicity to algae for most of the compounds. This indicates that they share the same mode of action between species. Similar relationships between logKOW and toxicities to fish and algae for baseline and less inert compounds suggest that they have similar critical body residues in the two species. Differences in excess toxicity for some compounds suggest that there is a difference of physiological structure and metabolism between fish and algae. Some reactive compounds (e.g. polyamines) exhibit greater toxic effects for algae than those for fish because of relatively low bio-uptake potential of these hydrophilic compounds in fish as compared with that in algae. Esters exhibiting greater toxicity in fish than that in algae indicate that metabolism can affect the discrimination of excess toxicity from baseline level. Algae growth inhibition is a very good surrogate for fish lethality. This is not only because overall toxicity sensitivity to algae is greater than that to fish, but also the excess toxicity calculated from algal toxicity can better reflect reactivity of compounds with target molecules than fish toxicity.

  2. Chemical composition in relation with biomass ash structure

    NASA Astrophysics Data System (ADS)

    Holubcik, Michal; Jandacka, Jozef

    2014-08-01

    Biomass combustion can be more complicated like combustion of fossil fuels because it is necessary to solve problems with lower ash melting temperature. It can cause a lot of problems during combustion process. Chemical composition of biomass ash has great impact on sinters and slags creation in ash because it affects structure of heated ash. In this paper was solved relation between chemical composition and structure of heated ash from three types of biomass (spruce wood, miscanthus giganteus and wheat straw). Amount of SiO2, CaO, MgO, Al2O3 and K2O was determined. Structure of heated ash was optically determined after heating to 1000 °C or 1200 °C. Results demonstrated that chemical composition has strong effect on structure and color of heated ash.

  3. Use of submitochondrial particles for prediction of chemical toxicity in man

    SciTech Connect

    Knobeloch, L.M.; Blondin, G.A.; Harkin, J.M. )

    1990-05-01

    Three bioassays which use submitochondrial electron transport particles (ETP) to evaluate chemical toxicity have been developed. These tests were initially designed for use in water quality monitoring. However, they are also valuable for assessing the toxicity of new and existing chemicals. The current investigation studies the ability of these procedures to predict in vivo tissue concentrations associated with clinical illness in man. To examine this potential, data obtained using the mitochondrial tests were compared to chemical concentrations measured in human blood samples obtained during the acute stage of chemical-induced illness. Twenty-nine chemicals were used in the comparison including 6 metals, 8 pesticides, 5 drugs, 4 solvents and 3 alcohols. The results of this study support the hypothesis that the mitochondrial bioassays can successfully predict the in vivo toxicity of many diverse chemicals. Properly performed and evaluated, these short-term tests may be useful in identifying potential environmental pollutants, selecting compounds for market development and prioritizing substances for more extensive testing in animals.

  4. Chemical composition analysis and authentication of whisky.

    PubMed

    Wiśniewska, Paulina; Dymerski, Tomasz; Wardencki, Waldemar; Namieśnik, Jacek

    2015-08-30

    Whisky (whiskey) is one of the most popular spirit-based drinks made from malted or saccharified grains, which should mature for at least 3 years in wooden barrels. High popularity of products usually causes a potential risk of adulteration. Thus authenticity assessment is one of the key elements of food product marketing. Authentication of whisky is based on comparing the composition of this alcohol with other spirit drinks. The present review summarizes all information about the comparison of whisky and other alcoholic beverages, the identification of type of whisky or the assessment of its quality and finally the authentication of whisky. The article also presents the various techniques used for analyzing whisky, such as gas and liquid chromatography with different types of detectors (FID, AED, UV-Vis), electronic nose, atomic absorption spectroscopy and mass spectrometry. In some cases the application of chemometric methods is also described, namely PCA, DFA, LDA, ANOVA, SIMCA, PNN, k-NN and CA, as well as preparation techniques such SPME or SPE. PMID:25315338

  5. Chemical composition analysis and authentication of whisky.

    PubMed

    Wiśniewska, Paulina; Dymerski, Tomasz; Wardencki, Waldemar; Namieśnik, Jacek

    2015-08-30

    Whisky (whiskey) is one of the most popular spirit-based drinks made from malted or saccharified grains, which should mature for at least 3 years in wooden barrels. High popularity of products usually causes a potential risk of adulteration. Thus authenticity assessment is one of the key elements of food product marketing. Authentication of whisky is based on comparing the composition of this alcohol with other spirit drinks. The present review summarizes all information about the comparison of whisky and other alcoholic beverages, the identification of type of whisky or the assessment of its quality and finally the authentication of whisky. The article also presents the various techniques used for analyzing whisky, such as gas and liquid chromatography with different types of detectors (FID, AED, UV-Vis), electronic nose, atomic absorption spectroscopy and mass spectrometry. In some cases the application of chemometric methods is also described, namely PCA, DFA, LDA, ANOVA, SIMCA, PNN, k-NN and CA, as well as preparation techniques such SPME or SPE.

  6. The chemical composition of Galactic beat Cepheids

    NASA Astrophysics Data System (ADS)

    Kovtyukh, V.; Lemasle, B.; Chekhonadskikh, F.; Bono, G.; Matsunaga, N.; Yushchenko, A.; Anderson, R. I.; Belik, S.; da Silva, R.; Inno, L.

    2016-08-01

    We determine the metallicity and detailed chemical abundances (α, iron-peak and neutron-capture elements) for the almost complete (18/24) sample of Galactic double mode Cepheids (also called beat Cepheids). Double mode Cepheids are Cepheids that pulsate in two modes simultaneously. We calibrate a new relation between their metallicity and their period ratio P1/P0. This linear relation allows to determine the metallicity of bimodal Cepheids with an accuracy of 0.03 dex in the range of [Fe/H] from +0.2 to -0.5 dex. By extrapolating the relation to Magellanic Clouds beat Cepheids, we provide their metallicity distribution function. Moreover, by using this relation, we also provide the first metallicity estimate for two double-mode F/1O Cepheids located in and beyond the Galactic bulge. Finally, we report the discovery of a super-Lithium rich double mode Cepheid V371 Per which has a Lithium abundance of logA(Li) = 3.54 ± 0.09 dex. Along with V1033 Cyg (which is an ordinary classical Cepheid), it is the second known Cepheid of such type in the Galaxy.

  7. Chemical compounds toxic to invertebrates isolated from marine cyanobacteria of potential relevance to the agricultural industry.

    PubMed

    Essack, Magbubah; Alzubaidy, Hanin S; Bajic, Vladimir B; Archer, John A C

    2014-10-29

    In spite of advances in invertebrate pest management, the agricultural industry is suffering from impeded pest control exacerbated by global climate changes that have altered rain patterns to favour opportunistic breeding. Thus, novel naturally derived chemical compounds toxic to both terrestrial and aquatic invertebrates are of interest, as potential pesticides. In this regard, marine cyanobacterium-derived metabolites that are toxic to both terrestrial and aquatic invertebrates continue to be a promising, but neglected, source of potential pesticides. A PubMed query combined with hand-curation of the information from retrieved articles allowed for the identification of 36 cyanobacteria-derived chemical compounds experimentally confirmed as being toxic to invertebrates. These compounds are discussed in this review.

  8. Toxic and teratogenic effects of chemical class fractions of a coal-gasification electrostatic precipitator tar.

    PubMed

    Schultz, T W; Dumont, J N; Buchanan, M V

    1983-12-01

    Dimethyl sulfoxide slurries of a coal gasifier electrostatic precipitator tar and its chemical class fractions were assayed for their toxicity and teratogenicity using early embryos of the frog Xenopus laevis. Of the 5 tar fractions the ether-soluble base and polyaromatic were found to be the most teratogenic and the ether-soluble acid and ether-soluble base were the most toxic. The teratogenic effects of the raw tar suggest synergism. The toxic effects to newly metamorphosed froglets is 1-2 orders of magnitude less than those observed for embryos. Chemical analysis shows dihydroxybenzenes and organonitrogen compounds to be the major components of the acid and base fractions, respectively. The neutral fractions contain mainly alkyl-substituted two-ring hydrocarbons.

  9. Toxicity Appraisal of Untreated Dyeing Industry Wastewater Based on Chemical Characterization and Short Term Bioassays.

    PubMed

    Akhtar, Muhammad Furqan; Ashraf, Muhammad; Javeed, Aqeel; Anjum, Aftab Ahmad; Sharif, Ali; Saleem, Ammara; Akhtar, Bushra; Khan, Abdul Muqeet; Altaf, Imran

    2016-04-01

    Characterizing wastewaters only on a chemical basis may be insufficient owing to their complex nature. The purpose of this study was to assess toxicity of textile dyeing wastewater based on analytical techniques and short term toxicity based bioassays. In this study, screening of the fractionated wastewater through GC-MS showed the presence of phenols, phthalic acid derivatives and chlorpyrifos. Metal analysis revealed that chromium, arsenic and mercury were present in amounts higher than the wastewater discharge limits. Textile dyeing wastewater was found to be highly mutagenic in the Ames test. DNA damage in sheep lymphocytes decreased linearly with an increase in the dilution of wastewater. MTT assay showed that 8.3 percent v/v wastewater decreased cell survival percentage to 50 %. It can be concluded from this study that short term toxicity tests such as Ames test, in vitro comet assay, and cytotoxicity assays may serve as useful indicators of wastewater pollution along with their organic and inorganic chemical characterizations.

  10. Chemical Compounds Toxic to Invertebrates Isolated from Marine Cyanobacteria of Potential Relevance to the Agricultural Industry

    PubMed Central

    Essack, Magbubah; Alzubaidy, Hanin S.; Bajic, Vladimir B.; Archer, John A. C.

    2014-01-01

    In spite of advances in invertebrate pest management, the agricultural industry is suffering from impeded pest control exacerbated by global climate changes that have altered rain patterns to favour opportunistic breeding. Thus, novel naturally derived chemical compounds toxic to both terrestrial and aquatic invertebrates are of interest, as potential pesticides. In this regard, marine cyanobacterium-derived metabolites that are toxic to both terrestrial and aquatic invertebrates continue to be a promising, but neglected, source of potential pesticides. A PubMed query combined with hand-curation of the information from retrieved articles allowed for the identification of 36 cyanobacteria-derived chemical compounds experimentally confirmed as being toxic to invertebrates. These compounds are discussed in this review. PMID:25356733

  11. Chemical warfare agent and biological toxin-induced pulmonary toxicity: could stem cells provide potential therapies?

    PubMed

    Angelini, Daniel J; Dorsey, Russell M; Willis, Kristen L; Hong, Charles; Moyer, Robert A; Oyler, Jonathan; Jensen, Neil S; Salem, Harry

    2013-01-01

    Chemical warfare agents (CWAs) as well as biological toxins present a significant inhalation injury risk to both deployed warfighters and civilian targets of terrorist attacks. Inhalation of many CWAs and biological toxins can induce severe pulmonary toxicity leading to the development of acute lung injury (ALI) as well as acute respiratory distress syndrome (ARDS). The therapeutic options currently used to treat these conditions are very limited and mortality rates remain high. Recent evidence suggests that human stem cells may provide significant therapeutic options for ALI and ARDS in the near future. The threat posed by CWAs and biological toxins for both civilian populations and military personnel is growing, thus understanding the mechanisms of toxicity and potential therapies is critical. This review will outline the pulmonary toxic effects of some of the most common CWAs and biological toxins as well as the potential role of stem cells in treating these types of toxic lung injuries.

  12. Species-specific predictive models of developmental toxicity using the ToxCast chemical library

    EPA Science Inventory

    EPA’s ToxCastTM project is profiling the in vitro bioactivity of chemicals to generate predictive models that correlate with observed in vivo toxicity. In vitro profiling methods are based on ToxCast data, consisting of over 600 high-throughput screening (HTS) and high-content sc...

  13. Virtual Liver: integrating in vitro and in vivo data to predict chemical-induced toxicity

    EPA Science Inventory

    It is difficult to assess the health impact of long-term exposure to low levels of contaminants from animal studies. Current methods for testing the toxicity of a single chemical can cost millions of dollars, take up to two years and sacrifice thousands of animals. In vitro model...

  14. Novel approaches to improving the chemical safety of the meat chain towards toxicants.

    PubMed

    Engel, E; Ratel, J; Bouhlel, J; Planche, C; Meurillon, M

    2015-11-01

    In addition to microbiological issues, meat chemical safety is a growing concern for the public authorities, chain stakeholders and consumers. Meat may be contaminated by various chemical toxicants originating from the environment, treatments of agricultural production or food processing. Generally found at trace levels in meat, these toxicants may harm human health during chronic exposure. This paper overviews the key issues to be considered to ensure better control of their occurrence in meat and assessment of the related health risk. We first describe potential contaminants of meat products. Strategies to move towards a more efficient and systematic control of meat chemical safety are then presented in a second part, with a focus on emerging approaches based on toxicogenomics. The third part presents mitigation strategies to limit the impact of process-induced toxicants in meat. Finally, the last part introduces methodological advances to refine chemical risk assessment related to the occurrence of toxicants in meat by quantifying the influence of digestion on the fraction of food contaminants that may be assimilated by the human body. PMID:26043665

  15. 75 FR 8889 - Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-26

    ... toxic chemicals as part of a 1993 final rule (December 1, 1993, 58 FR 63500). Hydrogen sulfide was... Federal Register of February 4, 1987 (52 FR 3479) to provide guidance regarding the recommended content... Federal Register of May 23, 1991 (56 FR 23703) regarding the recommended content of petitions to...

  16. SEDIMENT CHEMICAL CONTAMINATION AND TOXICITY ASSOCIATED WITH A COASTAL GOLF COURSE COMPLEX.

    EPA Science Inventory

    The increasing density of golf courses represents a potential source of sediment contamination to nearby coastal areas, the chemical and biological magnitude of which is almost unknown. The objective of this study was to determine the concentrations of contaminants and toxicities...

  17. CHEMICAL CONTAMINATION AND TOXICITY ASSOCIATED WITH A COASTAL GOLF COURSE COMPLEX

    EPA Science Inventory

    The increasing density of golf courses represents a potential source of contamination to nearby coastal areas, the chemical and biological magnitude of which is almost unknown. The objective of this study was to compare the concentrations of contaminants and toxicities of sedime...

  18. High Throughput Prioritization for Integrated Toxicity Testing Based on ToxCast Chemical Profiling

    EPA Science Inventory

    The rational prioritization of chemicals for integrated toxicity testing is a central goal of the U.S. EPA’s ToxCast™ program (http://epa.gov/ncct/toxcast/). ToxCast includes a wide-ranging battery of over 500 in vitro high-throughput screening assays which in Phase I was used to...

  19. The US EPAs ToxCast Program for the Prioritization and Prediction of Environmental Chemical Toxicity

    EPA Science Inventory

    To meet the need for evaluating large numbers of chemicals for potential toxicity, the U.S. Environmental Protection Agency has initiated a research project call ToxCast that makes use of recent advances in molecular biology and high-throughput screening. These technologies have ...

  20. Prioritizing ToxCast Chemicals Across Multiple Sectors of Toxicity Using ToxPi

    EPA Science Inventory

    The Toxicological Prioritization Index (ToxPi™) framework was developed as a decision-support tool to aid in the rational prioritization of chemicals for integrated toxicity testing. ToxPi consolidates information from multiple domains—including ToxCast™ in vitro bioactivity prof...

  1. 78 FR 69414 - Toxic Substances Control Act Chemical Testing; Receipt of Test Data

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-19

    ... October 21, 2011 (76 FR 65385) (FRL-8885-5) (docket ID number EPA-HQ-OPPT-2009-0112). The table in this... AGENCY Toxic Substances Control Act Chemical Testing; Receipt of Test Data AGENCY: Environmental Protection Agency (EPA). ACTION: Notice. SUMMARY: This notice announces EPA's receipt of test data on...

  2. Incorporating Biological, Chemical and Toxicological Knowledge into Predictive Models of Toxicity: Letter to the Editor

    EPA Science Inventory

    Thomas et al. (2012) recently published an evaluation of statistical models for classifying in vivo toxicity endpoints from ToxRefDB (Knudsen et al. 2009; Martin et al. 2009a and 2009b) using ToxCast in vitro bioactivity data (Judson et al. 2010) and chemical structure descriptor...

  3. CHEMICAL PRIORITIZATION FOR DEVELOPMENTAL TOXICITY USING LITERATURE MINING-BASED WEIGHTING OF TOXCAST ASSAYS

    EPA Science Inventory

    Defining a predictive model of developmental toxicity from in vitro and high-throughput screening (HTS) assays can be limited by the availability of developmental defects data. ToxRefDB (www.epa.gov/ncct/todrefdb) was built from animal studies on data-rich environmental chemicals...

  4. Species-Specific Predictive Signatures of Developmental Toxicity Using the ToxCast Chemical Library

    EPA Science Inventory

    EPA’s ToxCastTM project is profiling the in vitro bioactivity of chemicals to generate predictive signatures that correlate with observed in vivo toxicity. In vitro profiling methods from ToxCast data consist of over 600 high-throughput screening (HTS) and high-content screening ...

  5. The U.S. EPA's ToxCast Chemical Screening Program and Predictive Modeling of Toxicity

    EPA Science Inventory

    The ToxCast program was developed by the U.S. EPA's National Center for Computational Toxicology to provide cost-effective high-throughput screening for the potential toxicity of thousands of chemicals. Phase I screened 309 compounds in over 500 assays to evaluate concentration-...

  6. STRESS PATHWAY-BASED REPORTER ASSAYS TO ASSESS TOXICITY OF ENVIRONMENTAL CHEMICALS.

    EPA Science Inventory

    There is an increasing need for assays for the rapid and efficient assessment of toxicities of large numbers of environmental chemicals. To meet this need, we are developing cell-based reporter assays that measure the activation of key molecular stress pathways. We are using pro...

  7. 75 FR 72727 - Addition of National Toxicology Program Carcinogens; Community Right-to-Know Toxic Chemical...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-26

    ... emissions from vegetation, particularly from deciduous forests. The commenter cited sources that state that... criterion.'' EPA has published in the Federal Register of November 30, 1994 (59 FR 61432) a statement... EPCRA section 313 list of toxic chemicals? As discussed in the proposed rule (75 FR 17333, April 6,...

  8. Novel approaches to improving the chemical safety of the meat chain towards toxicants.

    PubMed

    Engel, E; Ratel, J; Bouhlel, J; Planche, C; Meurillon, M

    2015-11-01

    In addition to microbiological issues, meat chemical safety is a growing concern for the public authorities, chain stakeholders and consumers. Meat may be contaminated by various chemical toxicants originating from the environment, treatments of agricultural production or food processing. Generally found at trace levels in meat, these toxicants may harm human health during chronic exposure. This paper overviews the key issues to be considered to ensure better control of their occurrence in meat and assessment of the related health risk. We first describe potential contaminants of meat products. Strategies to move towards a more efficient and systematic control of meat chemical safety are then presented in a second part, with a focus on emerging approaches based on toxicogenomics. The third part presents mitigation strategies to limit the impact of process-induced toxicants in meat. Finally, the last part introduces methodological advances to refine chemical risk assessment related to the occurrence of toxicants in meat by quantifying the influence of digestion on the fraction of food contaminants that may be assimilated by the human body.

  9. Evaluating the Toxicity Pathways Using High-Throughput Environmental Chemical Data

    EPA Science Inventory

    The application of HTS methods to the characterization of human phenotypic response to environmental chemicals is a largely unexplored area of pharmacogenomics. The U.S. Environmental Protection Agency (EPA), through its ToxCast program, is developing predictive toxicity approach...

  10. Predicting aquatic toxicities of chemical pesticides in multiple test species using nonlinear QSTR modeling approaches.

    PubMed

    Basant, Nikita; Gupta, Shikha; Singh, Kunwar P

    2015-11-01

    In this study, we established nonlinear quantitative-structure toxicity relationship (QSTR) models for predicting the toxicities of chemical pesticides in multiple aquatic test species following the OECD (Organization for Economic Cooperation and Development) guidelines. The decision tree forest (DTF) and decision tree boost (DTB) based QSTR models were constructed using a pesticides toxicity dataset in Selenastrum capricornutum and a set of six descriptors. Other six toxicity data sets were used for external validation of the constructed QSTRs. Global QSTR models were also constructed using the combined dataset of all the seven species. The diversity in chemical structures and nonlinearity in the data were evaluated. Model validation was performed deriving several statistical coefficients for the test data and the prediction and generalization abilities of the QSTRs were evaluated. Both the QSTR models identified WPSA1 (weighted charged partial positive surface area) as the most influential descriptor. The DTF and DTB QSTRs performed relatively better than the single decision tree (SDT) and support vector machines (SVM) models used as a benchmark here and yielded R(2) of 0.886 and 0.964 between the measured and predicted toxicity values in the complete dataset (S. capricornutum). The QSTR models applied to six other aquatic species toxicity data yielded R(2) of >0.92 (DTF) and >0.97 (DTB), respectively. The prediction accuracies of the global models were comparable with those of the S. capricornutum models. The results suggest for the appropriateness of the developed QSTR models to reliably predict the aquatic toxicity of chemicals and can be used for regulatory purpose.

  11. Predicting aquatic toxicities of chemical pesticides in multiple test species using nonlinear QSTR modeling approaches.

    PubMed

    Basant, Nikita; Gupta, Shikha; Singh, Kunwar P

    2015-11-01

    In this study, we established nonlinear quantitative-structure toxicity relationship (QSTR) models for predicting the toxicities of chemical pesticides in multiple aquatic test species following the OECD (Organization for Economic Cooperation and Development) guidelines. The decision tree forest (DTF) and decision tree boost (DTB) based QSTR models were constructed using a pesticides toxicity dataset in Selenastrum capricornutum and a set of six descriptors. Other six toxicity data sets were used for external validation of the constructed QSTRs. Global QSTR models were also constructed using the combined dataset of all the seven species. The diversity in chemical structures and nonlinearity in the data were evaluated. Model validation was performed deriving several statistical coefficients for the test data and the prediction and generalization abilities of the QSTRs were evaluated. Both the QSTR models identified WPSA1 (weighted charged partial positive surface area) as the most influential descriptor. The DTF and DTB QSTRs performed relatively better than the single decision tree (SDT) and support vector machines (SVM) models used as a benchmark here and yielded R(2) of 0.886 and 0.964 between the measured and predicted toxicity values in the complete dataset (S. capricornutum). The QSTR models applied to six other aquatic species toxicity data yielded R(2) of >0.92 (DTF) and >0.97 (DTB), respectively. The prediction accuracies of the global models were comparable with those of the S. capricornutum models. The results suggest for the appropriateness of the developed QSTR models to reliably predict the aquatic toxicity of chemicals and can be used for regulatory purpose. PMID:26142614

  12. Seasonal variation in the chemical composition of two tropical seaweeds.

    PubMed

    Marinho-Soriano, E; Fonseca, P C; Carneiro, M A A; Moreira, W S C

    2006-12-01

    The chemical composition of red seaweed Gracilaria cervicornis and brown seaweed Sargassum vulgare from Brazil was investigated. In this study, the relationship between the nutritive components of each species and the environment was established. Protein content varied from 23.05+/-3.04% to 15.97+/-3.04%. The highest value was found in G. cervicornis. The protein levels were positively correlated with nitrogen content and negatively with water temperature and salinity. Carbohydrate contents of both species varied significantly (p<0.01) and the values observed were superior to others chemical constituents. Contrary to carbohydrates, the lipid concentrations were the lowest recorded chemical component and varied slightly between the two species. Ash content was greater in S. vulgare (14.20+/-3.86) than in G. cervicornis (7.74+/-1.15). In general the variation in chemical composition was related to environment. PMID:16311028

  13. Multiple life stage sensitivity of a deposit-feeding polychaete to chemical toxicants in sediment

    SciTech Connect

    Rice, C.A.; Sibley, T.; Ylitalo, G.M.; Casillas, E.

    1995-12-31

    By focusing on acute toxicity in species with habitat and food preferences often quite different from the environments of primary interest; that is, the depositional, fine-grained, organically enriched benthos, standard methods of testing sediment toxicity using single species have important problems of relevance in terms of test endpoints and target species. This study addresses these issues by building a set of baseline toxicity data that emphasizes critical life stage sensitivity over a wide range of toxicant concentrations in long-term sediment exposures for an animal with a model life history. The opportunistic, deposit-feeding polychaete Armandia brevis was exposed to sediments supplemented with fluoranthene, cadmium, copper, lead, and mercury, alone and in a model mixture, for 60 days. Mortality and emergence from sediment were recorded daily, and growth and maturity were measured at 20, 40, and 60d. To measure recruitment, cultured larvae were presented with the same sediments and allowed to settle and complete metamorphosis. Differential endpoint sensitivity, and differential chemical toxicity were evaluated. In addition, sediment and tissue concentrations of organic toxicants were used to link toxic responses to body burdens, and to consider the role of benthic infauna as contaminant vectors in the marine environment.

  14. Correlation between biogas yield and chemical composition of energy crops.

    PubMed

    Dandikas, V; Heuwinkel, H; Lichti, F; Drewes, J E; Koch, K

    2014-12-01

    The scope of this study was to investigate the influence of the chemical composition of energy crops on biogas and methane yield. In total, 41 different plants were analyzed in batch test and their chemical composition was determined. For acid detergent lignin (ADL) content below 10% of total solids, a significant negative correlation for biogas and methane yields (r≈-0.90) was observed. Based on a simple regression analysis, more than 80% of the sample variation can be explained through ADL. Based on a principal component analysis and multiple regression analysis, ADL and hemicellulose are suggested as suitable model variables for biogas yield potential predictions across plant species. PMID:25443623

  15. Fuel options from microalgae with representative chemical compositions

    SciTech Connect

    Feinberg, D. A.

    1984-07-01

    Representative species of microalgae are examined with respect to their reported chemical compositions. Each species is analyzed under a variety of culture conditions, with the objective being to characterize an optimum mixture of fuel products (e.g., methane, ethanol, methylester) which should be produced by the particular species. Historically the emphasis has been on the entire algal cell mass. Using the reported chemical composition for the representative species under specific sets of growth conditions, some conclusions can be drawn about the preferred fuel product conversion routes that could be employed. 10 references, 7 figures, 12 tables.

  16. Chemical vapor infiltration of non-oxide ceramic matrix composites

    SciTech Connect

    Besmann, T.M.; Stinton, D.P.; Lowden, R.A.

    1993-12-31

    Continuous fiber ceramic composites are enabling new, high temperature structural applications. Chemical vapor infiltration methods for producing these composites are being investigated, with the complexity of filament weaves and deposition chemistry merged with standard heat and mass transport relationships. Silicon carbide- based materials are, by far, the most mature, and are already being used in aerospace applications. This paper addresses the state-of-the-art of the technology and outlines current issues.

  17. Oral LD50 toxicity modeling and prediction of per- and polyfluorinated chemicals on rat and mouse.

    PubMed

    Bhhatarai, Barun; Gramatica, Paola

    2011-05-01

    Quantitative structure-activity relationship (QSAR) analyses were performed using the LD(50) oral toxicity data of per- and polyfluorinated chemicals (PFCs) on rodents: rat and mouse. PFCs are studied under the EU project CADASTER which uses the available experimental data for prediction and prioritization of toxic chemicals for risk assessment by using the in silico tools. The methodology presented here applies chemometrical analysis on the existing experimental data and predicts the toxicity of new compounds. QSAR analyses were performed on the available 58 mouse and 50 rat LD(50) oral data using multiple linear regression (MLR) based on theoretical molecular descriptors selected by genetic algorithm (GA). Training and prediction sets were prepared a priori from available experimental datasets in terms of structure and response. These sets were used to derive statistically robust and predictive (both internally and externally) models. The structural applicability domain (AD) of the models were verified on 376 per- and polyfluorinated chemicals including those in REACH preregistration list. The rat and mouse endpoints were predicted by each model for the studied compounds, and finally 30 compounds, all perfluorinated, were prioritized as most important for experimental toxicity analysis under the project. In addition, cumulative study on compounds within the AD of all four models, including two earlier published models on LC(50) rodent analysis was studied and the cumulative toxicity trend was observed using principal component analysis (PCA). The similarities and the differences observed in terms of descriptors and chemical/mechanistic meaning encoded by descriptors to prioritize the most toxic compounds are highlighted.

  18. A new index to assess chemicals increasing the greenhouse effect based on their toxicity to algae.

    PubMed

    Wang, Ting; Zhang, Xiaoxian; Tian, Dayong; Gao, Ya; Lin, Zhifen; Liu, Ying; Kong, Lingyun

    2015-11-01

    CO2, as the typical greenhouse gas causing the greenhouse effect, is a major global environmental problem and has attracted increasing attention from governments. Using algae to eliminate CO2, which has been proposed as an effective way to reduce the greenhouse effect in the past decades, can be disturbed by a growing number of artificial chemicals. Thus, seven types of chemicals and Selenastrum capricornutum (algae) were examined in this study, and the good consistency between the toxicity of artificial chemicals to algae and the disturbance of carbon fixation by the chemicals was revealed. This consistency showed that the disturbance of an increasing number of artificial chemicals to the carbon fixation of algae might be a "malware" worsening the global greenhouse effect. Therefore, this study proposes an original, promising index to assess the risk of deepening the greenhouse effect by artificial chemicals before they are produced and marketed. PMID:26520250

  19. A new index to assess chemicals increasing the greenhouse effect based on their toxicity to algae.

    PubMed

    Wang, Ting; Zhang, Xiaoxian; Tian, Dayong; Gao, Ya; Lin, Zhifen; Liu, Ying; Kong, Lingyun

    2015-11-01

    CO2, as the typical greenhouse gas causing the greenhouse effect, is a major global environmental problem and has attracted increasing attention from governments. Using algae to eliminate CO2, which has been proposed as an effective way to reduce the greenhouse effect in the past decades, can be disturbed by a growing number of artificial chemicals. Thus, seven types of chemicals and Selenastrum capricornutum (algae) were examined in this study, and the good consistency between the toxicity of artificial chemicals to algae and the disturbance of carbon fixation by the chemicals was revealed. This consistency showed that the disturbance of an increasing number of artificial chemicals to the carbon fixation of algae might be a "malware" worsening the global greenhouse effect. Therefore, this study proposes an original, promising index to assess the risk of deepening the greenhouse effect by artificial chemicals before they are produced and marketed.

  20. Chemical Composition of Laboratory Generated Seafoam Particles

    NASA Astrophysics Data System (ADS)

    Tyree, C. A.; Alexandrova, O. A.; Allen, J. O.

    2005-12-01

    . Surprisingly, the size and number of seafoam particles was independent of organic content; this is in contrast to previous laboratory experiments that showed seafoam particle numbers were enhanced when surface-active organics were added to artificial seawater (Garrett, 1968). We present recent measurements of the composition and enrichment of laboratory seafoam particles, which we propose approximate remote marine boundary layer particles.

  1. Chemical comparison and acute toxicity of water accommodated fraction (WAF) of source and field collected Macondo oils from the Deepwater Horizon spill.

    PubMed

    Faksness, Liv-Guri; Altin, Dag; Nordtug, Trond; Daling, Per S; Hansen, Bjørn Henrik

    2015-02-15

    Two Source oils and five field collected oil residues from the Deepwater Horizon incident were chemically characterized. Water accommodated fractions (WAFs) of the Source oils and two of the field-weathered oils were prepared to evaluate the impact of natural weathering on the chemical composition and the acute toxicity of the WAFs. Toxicity test species representing different tropic levels were used (the primary producer Skeletonema costatum (algae) and the herbivorous copepod Acartia tonsa). The results suggest that the potential for acute toxicity is higher in WAFs from non-weathered oils than WAFs from the field weathered oils. The Source oils contained a large fraction of soluble and bioavailable components (such as BTEX (benzene, toluene, ethyl benzene, xylenes) and naphthalene), whereas in the surface collected oils these components were depleted by dissolution into the water column as the oil rose to the surface and by evaporative loss after reaching the sea surface. PMID:25534626

  2. A combined approach to investigate the toxicity of an industrial landfill's leachate: Chemical analyses, risk assessment and in vitro assays

    SciTech Connect

    Baderna, D.; Maggioni, S.; Boriani, E.; Gemma, S.; Molteni, M.; Lombardo, A.; Colombo, A.; Bordonali, S.; Rotella, G.; Lodi, M.; Benfenati, E.

    2011-05-15

    Solid wastes constitute an important and emerging problem. Landfills are still one of the most common ways to manage waste disposal. The risk assessment of pollutants from landfills is becoming a major environmental issue in Europe, due to the large number of sites and to the importance of groundwater protection. Furthermore, there is lack of knowledge for the environmental, ecotoxicological and toxicological characteristics of most contaminants contained into landfill leacheates. Understanding leachate composition and creating an integrated strategy for risk assessment are currently needed to correctly face the landfill issues and to make projections on the long-term impacts of a landfill, with particular attention to the estimation of possible adverse effects on human health and ecosystem. In the present study, we propose an integrated strategy to evaluate the toxicity of the leachate using chemical analyses, risk assessment guidelines and in vitro assays using the hepatoma HepG2 cells as a model. The approach was applied on a real case study: an industrial waste landfill in northern Italy for which data on the presence of leachate contaminants are available from the last 11 years. Results from our ecological risk models suggest important toxic effects on freshwater fish and small rodents, mainly due to ammonia and inorganic constituents. Our results from in vitro data show an inhibition of cell proliferation by leachate at low doses and cytotoxic effect at high doses after 48 h of exposure. - Research highlights: {yields} We study the toxicity of leachate from a non-hazardous industrial waste landfill. {yields} We perform chemical analyses, risk assessments and in vitro assays on HepG2 cells. {yields} Risk models suggest toxic effects due to ammonia and inorganic constituents. {yields} In vitro assays show that leachate inhibits cell proliferation at low doses. {yields} Leachate can induce cytotoxic effects on HepG2 cells at high doses.

  3. Application of chemical toxicity distributions to ecotoxicology data requirements under REACH.

    PubMed

    Williams, E Spencer; Berninger, Jason P; Brooks, Bryan W

    2011-08-01

    The European Union's REACH regulation has further highlighted the lack of ecotoxicological data for substances in the marketplace. The mandates under REACH (registration, evaluation, authorization, and restriction of chemicals) to produce data and minimize testing on vertebrates present an impetus for advanced hazard assessment techniques using read-across. Research in our group has recently focused on probabilistic ecotoxicological hazard assessment approaches using chemical toxicity distributions (CTDs). Using available data for chemicals with similar modes of action or within a chemical class may allow for selection of a screening point value (SPV) for development of environmental safety values, based on a probabilistic distribution of toxicity values for a specific endpoint in an ecological receptor. Ecotoxicity data for acetylcholinesterase inhibitors and surfactants in Daphnia magna and Pimephales promelas were gathered from several data sources, including the U.S. Environmental Protection Agency's ECOTOX and Pesticides Ecotoxicity databases, the peer-reviewed literature, and the Human and Environmental Risk Assessment (HERA) project. Chemical toxicity distributions were subsequently developed, and the first and fifth centiles were used as SPVs for the development of screening-predicted no-effect concentrations (sPNECs). The first and fifth centiles of these distributions were divided by an assessment factor of 1,000, as recommended by REACH guidance. Use of screening values created using these techniques could support the processes of data dossier development and environmental exposure assessment, allowing for rigorous prioritization in testing and monitoring to fill data gaps.

  4. Detection of toxic industrial chemicals in water supplies using surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Spencer, Kevin M.; Sylvia, James M.; Spencer, Sarah A.; Clauson, Susan L.

    2010-04-01

    An effective method to create fear in the populace is to endanger the water supply. Homeland Security places significant importance on ensuring drinking water integrity. Beyond terrorism, accidental supply contamination from a spill or chemical residual increases is a concern. A prominent class of toxic industrial chemicals (TICs) is pesticides, which are prevalent in agricultural use and can be very toxic in minute concentrations. Detection of TICs or warfare agents must be aggressive; the contaminant needs to be rapidly detected and identified to enable isolation and remediation of the contaminated water while continuing a clean water supply for the population. Awaiting laboratory analysis is unacceptable as delay in identification and remediation increases the likelihood of infection. Therefore, a portable or online water quality sensor is required that can produce rapid results. In this presentation, Surface-Enhanced Raman Spectroscopy (SERS) is discussed as a viable fieldable sensor that can be immersed directly into the water supply and can provide results in <5 minutes from the time the instrument is turned on until analysis is complete. The ability of SERS to detect several chemical warfare agent degradation products, simulants and toxic industrial chemicals in distilled water, tap water and untreated water will be shown. In addition, results for chemical warfare agent degradation products and simulants will be presented. Receiver operator characteristic (ROC) curves will also be presented.

  5. Modeling and managing toxic chemicals: The Lake Michigan mass balance study

    SciTech Connect

    Endicott, D.D.; Richardson, W.L.

    1995-12-31

    The control and management of anthropogenic chemicals in the Great Lakes is an issue of great concern for 2 nations, 9 states and provinces, and 33 million people. As loadings from identified sources have been reduced, sometimes dramatic declines in toxic chemical concentrations have been observed to follow. However, human health and ecological effects from toxic chemicals remain topics of concern. There is also scientific debate regarding what factors control current toxic chemical concentrations in biotic and abiotic components of the Great lakes ecosystem. To address this latter issue, mathematical models are being developed to simulate the sources, transport, bioavailability, and bioaccumulation of four target chemicals (atrazine, mercury, PCBs, and trans-nonachlor). Preliminary modeling assessment by the authors suggested that PCB concentrations in Lake Michigan lake trout would remain greater than 1 mg/kg, even if all point and nonpoint sources in the watershed were eliminated. 2 factors control this result: (1) atmospheric sources are the largest PCB load component, and (2) the release of PCBs from the lake sediments by resuspension represents a huge internal mass flux. However, current data does not allow accurate estimation of either quantity. Because of the major ecological and economical consequences of decisions based upon the mass balance assessment, the modeling results require scientific confirmation.

  6. Toxic chemicals: Can what we don't know harm us?

    SciTech Connect

    Fur, P.L. de; Foersom, L.

    2000-02-01

    The Chesapeake Bay Program began more than 20 years ago with assessments of a number of key areas, relying on measurements of habitats, plant and animal populations, and physical and chemical conditions. This approach used wildlife as indicators of Bay health and of potential threats to human health. The extent of toxic chemical contamination was one of the assessment endpoints in the original survey. When the initial assessment was completed in 1983, the results of Bay-wide surveys indicated that several specific waterways were contaminated. These waters, the Elizabeth River, Virginia, the James River, Virginia, and Baltimore Harbor, Maryland, were targeted for specific actions to address the problems of historical and ongoing pollution. Over the past 10 years or more, data on some toxic chemical releases into and levels in the environment have been collected, but these data are limited in scope. Furthermore, these data are not used to assess threats to human health or more generally to nonhuman endpoints. New and existing data on environmental levels of chemicals and effects at low concentrations provide evidence that toxic chemicals may threaten both human and nonhuman health in the wider Bay system.

  7. A comparison of the toxicity of 30 reference chemicals to Daphnia magna and Daphnia pulex

    SciTech Connect

    Lilius, H.; Haestbacka, T.; Isomaa, B.

    1995-12-01

    To determine whether significant differences exist in the sensitivity of different Daphnia species to toxicants, the acute toxicity of the first 30 MEIC (multicenter evaluation of in vitro cytotoxicity) reference chemicals was determined in two species of Daphnia: D. magna and D. pulex. Correlation and regression analysis of the EC50 data for immobilization showed a very good concordance (r = 0.97, slope = 1.02). A comparison between the EC50 data obtained for D. magna by two laboratories independently for the 50 MEIC chemicals also showed a good concordance (r = 0.93, slope = 0.91). In both comparisons the regression line did not differ significantly from the regression line for a 1:1 regression. The authors conclude that their study, including a set of reference chemicals, indicates that is no difference in the overall sensitivity of the two Daphnia species and the two clones of D. magna.

  8. Cutaneous signs of systemic toxicity due to dioxins and related chemicals

    SciTech Connect

    Dunagin, W.G.

    1984-04-01

    The controversy about dioxin effects on human health received a great deal of attention recently when the State of Missouri was declared to have a dioxin crisis. However, dioxin and several related chemicals are widespread throughout the world. Cutaneous signs play an important part in evaluating toxicity of dioxin and similar chemicals. Chloracne is the most sensitive indicator of significant dioxin exposure. Porphyria cutanea tarda and hyperpigmentation are other known cutaneous effects, and malignant fibrous histiocytomas of the skin may possibly be associated, although data are inconclusive on this point. The AMC Council on Scientific Affairs recommended that all physicians become familiar with chloracne and other toxic effects of dioxin. Dermatologists, especially, should be aware of the problem and may discover early cases of previously unsuspected exposure to this group of chemicals.

  9. Use of biosensors to screen urine samples for potentially toxic chemicals.

    PubMed

    Horswell, Jacqui; Dickson, Stuart

    2003-09-01

    Forensic toxicology laboratories are often required to implicate or exclude poisoning as a factor in a death or unexplained illness. An analytical tool which enables toxicologists to screen a wide variety of common poisons would be extremely useful. In this paper, we describe the use of a bacterial biosensor for detecting the presence of commonly encountered potentially toxic chemicals in urine. The biosensor responds to any chemical that causes metabolic stress to the bacterial cell and the response is in direct proportion to the concentration of the stressor. This allows a measure of the concentration of a toxicant in urine, without knowing exactly what the toxic compound(s) may be. This affords a distinct advantage over conventional analytical techniques, which require an extensive screening program before it is even known that a toxic compound is present. This preliminary investigation has shown that this biosensor can indicate the presence, in urine, of herbicides such as glyphosate, 2,4-dichlorophenoxyacetic acid, and 2,4,5-trichlorophenoxyacetic acid; the biocide pentachlorophenol; or inorganic poisons such as arsenic, mercury, and cyanide. The biosensor was also shown to be sensitive to a concentration range of these toxicants likely to be found in samples submitted for toxicological analysis.

  10. Improved method for in vitro assessment of dermal toxicity for volatile organic chemicals.

    PubMed

    Rogers, James V; McDougal, James N

    2002-09-01

    Cell culture methods are being developed to assess the dermal toxicity (irritancy and corrosion) of chemicals. These in vitro methods are being validated to categorize chemicals as irritating or non-irritating to humans. Currently, these cell culture tests are useful to assist in the ranking of chemicals for irritancy, but they are not useful for quantitative risk assessment for two reasons. First, for volatile chemicals the amount of chemical in the media that the cells are exposed to may decrease with exposure time. Also, effective concentrations such as EC(50) and IC(50) are reported as the concentrations in the media not the skin tissue/cells. We have developed an in vitro approach for dermal toxicity testing of volatile chemicals that avoids these problems. Using sealed vials lacking a headspace, dermal equivalents (dermal fibroblasts in a collagen matrix) were exposed to culture medium containing a test chemical (m-xylene) and compared to a traditional open well culture system. We found that about 90% of the m-xylene was lost from the open well plates and the viability was 4-6 times greater than in the closed system. Partition coefficients were measured and used to estimate the m-xylene concentration in the fibroblasts. The EC(50) for m-xylene in the dermal equivalents was 833.13+/-35.33 microg m-xylene per gram of fibroblasts. This method will provide an effective approach to relate target cell chemical concentration to cellular responses. Based on this method, a biologically-based mathematical model could be used to determine an equivalent external dose for a specific toxic end point.

  11. Acclimation of Chlamydomonas reinhardtii to ultraviolet radiation and its impact on chemical toxicity.

    PubMed

    Korkaric, Muris; Xiao, Mao; Behra, Renata; Eggen, Rik I L

    2015-10-01

    The toxicity of chemical pollutants can be modulated under stressful environmental conditions, such as increased temperature, salinity or ultraviolet radiation (UVR), due to the interaction of effects during simultaneous stressor exposure. However, organisms may acclimate to such conditions by activation of physiological and biochemical defence mechanisms. In sequential exposures, organisms acclimated to environmental stressors may display an increased sensitivity or co-tolerance towards chemical pollutants. It has been suggested that co-tolerance might be expected for similarly acting stressors due to common defence mechanisms. To test this for combinations of UVR and chemical stressors, we first acclimatized the model green alga Chlamydomonas reinhardtii to UVR and subsequently compared the sensitivity of UVR pre-exposed and control algae towards chemicals. Selected chemicals all act on photosynthesis and thus share a common physiological target, but display distinct toxicity mechanisms. Results showed that UVR pre-exposure for four days partially inhibited algal growth and photosynthesis, but also increased algal tolerance to higher UVR levels, confirming UVR acclimation. HPLC analysis of algal pigments indicated that UVR acclimation might in part be explained by the protective function of lutein while the contribution of UVR absorbing compounds was less clear. Challenge exposure to chemicals in the absence of UVR showed that acclimated algae were co-tolerant to the photosensitizer rose bengal, but not to the herbicides paraquat and diuron, suggesting that the fast physiological and biochemical defence mechanisms that conferred tolerance of algae towards higher UVR levels were related to singlet oxygen defence. The presented study suggests that knowledge of the molecular toxicity mechanisms of chemicals, rather than their general physiological target, is needed in order to predict co-tolerance between environmental and chemical stressors. PMID:26349947

  12. Acclimation of Chlamydomonas reinhardtii to ultraviolet radiation and its impact on chemical toxicity.

    PubMed

    Korkaric, Muris; Xiao, Mao; Behra, Renata; Eggen, Rik I L

    2015-10-01

    The toxicity of chemical pollutants can be modulated under stressful environmental conditions, such as increased temperature, salinity or ultraviolet radiation (UVR), due to the interaction of effects during simultaneous stressor exposure. However, organisms may acclimate to such conditions by activation of physiological and biochemical defence mechanisms. In sequential exposures, organisms acclimated to environmental stressors may display an increased sensitivity or co-tolerance towards chemical pollutants. It has been suggested that co-tolerance might be expected for similarly acting stressors due to common defence mechanisms. To test this for combinations of UVR and chemical stressors, we first acclimatized the model green alga Chlamydomonas reinhardtii to UVR and subsequently compared the sensitivity of UVR pre-exposed and control algae towards chemicals. Selected chemicals all act on photosynthesis and thus share a common physiological target, but display distinct toxicity mechanisms. Results showed that UVR pre-exposure for four days partially inhibited algal growth and photosynthesis, but also increased algal tolerance to higher UVR levels, confirming UVR acclimation. HPLC analysis of algal pigments indicated that UVR acclimation might in part be explained by the protective function of lutein while the contribution of UVR absorbing compounds was less clear. Challenge exposure to chemicals in the absence of UVR showed that acclimated algae were co-tolerant to the photosensitizer rose bengal, but not to the herbicides paraquat and diuron, suggesting that the fast physiological and biochemical defence mechanisms that conferred tolerance of algae towards higher UVR levels were related to singlet oxygen defence. The presented study suggests that knowledge of the molecular toxicity mechanisms of chemicals, rather than their general physiological target, is needed in order to predict co-tolerance between environmental and chemical stressors.

  13. Assessing contaminant sensitivity of endangered and threatened aquatic species: Part I. Acute toxicity of five chemicals

    USGS Publications Warehouse

    Dwyer, F.J.; Mayer, F.L.; Sappington, L.C.; Buckler, D.R.; Bridges, C.M.; Greer, I.E.; Hardesty, D.K.; Henke, C.E.; Ingersoll, C.G.; Kunz, J.L.; Whites, D.W.; Augspurger, T.; Mount, D.R.; Hattala, K.; Neuderfer, G.N.

    2005-01-01

    Assessment of contaminant impacts to federally identified endangered, threatened and candidate, and state-identified endangered species (collectively referred to as "listed" species) requires understanding of a species' sensitivities to particular chemicals. The most direct approach would be to determine the sensitivity of a listed species to a particular contaminant or perturbation. An indirect approach for aquatic species would be application of toxicity data obtained from standard test procedures and species commonly used in laboratory toxicity tests. Common test species (fathead minnow, Pimephales promelas; sheepshead minnow, Cyprinodon variegatus; and rainbow trout, Oncorhynchus mykiss) and 17 listed or closely related species were tested in acute 96-hour water exposures with five chemicals (carbaryl, copper, 4-nonylphenol, pentachlorophenol, and permethrin) representing a broad range of toxic modes of action. No single species was the most sensitive to all chemicals. For the three standard test species evaluated, the rainbow trout was more sensitive than either the fathead minnow or sheepshead minnow and was equal to or more sensitive than listed and related species 81% of the time. To estimate an LC50 for a listed species, a factor of 0.63 can be applied to the geometric mean LC50 of rainbow trout toxicity data, and more conservative factors can be determined using variance estimates (0.46 based on 1 SD of the mean and 0.33 based on 2 SD of the mean). Additionally, a low- or no-acute effect concentration can be estimated by multiplying the respective LC50 by a factor of approximately 0.56, which supports the United States Environmental Protection Agency approach of multiplying the final acute value by 0.5 (division by 2). When captive or locally abundant populations of listed fish are available, consideration should be given to direct testing. When direct toxicity testing cannot be performed, approaches for developing protective measures using common test

  14. The complex interaction between marine debris and toxic chemicals in the ocean.

    PubMed

    Engler, Richard E

    2012-11-20

    Marine debris, especially plastic debris, is widely recognized as a global environmental problem. There has been substantial research on the impacts of plastic marine debris, such as entanglement and ingestion. These impacts are largely due to the physical presence of plastic debris. In recent years there has been an increasing focus on the impacts of toxic chemicals as they relate to plastic debris. Some plastic debris acts as a source of toxic chemicals: substances that were added to the plastic during manufacturing leach from plastic debris. Plastic debris also acts as a sink for toxic chemicals. Plastic sorbs persistent, bioaccumulative, and toxic substances (PBTs), such as polychlorinated biphenyls (PCBs) and dioxins, from the water or sediment. These PBTs may desorb when the plastic is ingested by any of a variety of marine species. This broad look at the current research suggests that while there is significant uncertainty and complexity in the kinetics and thermodynamics of the interaction, plastic debris appears to act as a vector transferring PBTs from the water to the food web, increasing risk throughout the marine food web, including humans. Because of the extremely long lifetime of plastic and PBTs in the ocean, prevention strategies are vital to minimizing these risks.

  15. Chemical composition of cottonseed affected by cropping management practices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cottonseed is a valuable raw material for a range of food, animal feed, and industrial (such as adhesives) products. Chemical composition is one of the critical parameters to evaluate cottonseed's quality and potential end use. However, the information on the impacts of cropping management practices...

  16. Coma chemical composition at the Abydos landing site

    NASA Astrophysics Data System (ADS)

    Morse, A.; Sheridan, S.; Morgan, G.; Andrews, D.; Barber, S.; Wright, I.

    2015-10-01

    The Ptolemy instrument, onboard the Rosetta Philae Lander, made measurements of the chemical composition of the coma mid-bounce, just after the non-nominal landing on the surface, and subsequently at the Abydos landing site. This presentation will discuss Ptolemy's operations throughout this 45 hour period and the results obtained.

  17. Composition and Thermodynamic Properties of Air in Chemical Equilibrium

    NASA Technical Reports Server (NTRS)

    Moeckel, W E; Weston, Kenneth C

    1958-01-01

    Charts have been prepared relating the thermodynamic properties of air in chemical equilibrium for temperatures to 15,000 degrees k and for pressures 10(-5) to 10 (plus 4) atmospheres. Also included are charts showing the composition of air, the isentropic exponent, and the speed of sound. These charts are based on thermodynamic data calculated by the National Bureau of Standards.

  18. Computer program determines chemical composition of physical system at equilibrium

    NASA Technical Reports Server (NTRS)

    Kwong, S. S.

    1966-01-01

    FORTRAN 4 digital computer program calculates equilibrium composition of complex, multiphase chemical systems. This is a free energy minimization method with solution of the problem reduced to mathematical operations, without concern for the chemistry involved. Also certain thermodynamic properties are determined as byproducts of the main calculations.

  19. Chemical composition and bioactivity studies of Alpinia nigra essential oils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Free radical scavenging, bactericidal and bitting deterrent properties of Alpinia nigra essential oils (EOs) were investigated in the present study. Chemical composition of the EOs were analyzed using GC-MS/GC-FID which revealed the presence of 63 constituents including ß-caryophyllene as major comp...

  20. The possibility of garbage, medical and other toxic waste treatment by plasma chemical method

    SciTech Connect

    Rutberg, P.G.; Safronov, A.A.; Bratsev, A.N.; Kuznetsov, V.E.

    1998-12-31

    This paper describes the creation of plasma facility for treatment of toxic waste. All industrialized countries are greatly interested in plasma chemical technology application for the destruction of different types of industrial, building, purification works toxic waste and waste of plants for garbage treatment. On the basis of three-phase plasma generators with power 0.1--1 MW intended for work in air a row of pilot facilities were created for carrying out of experiments on destruction of medical waste and fluorine-chlorine containing substances. The obtained results allow to design and create pilot-commercial plants with treatment productivity of 200 t/24 hours.

  1. Crystal chemical characteristics of ellestadite-type apatite: implications for toxic metal immobilization.

    PubMed

    Fang, Y N; Ritter, Clemens; White, T J

    2014-11-14

    The ellestadite apatites Ca10[(SiO4)x(PO4)6-2x(SO4)x]Cl2 were studied by powder X-ray and neutron diffraction to establish baseline crystallographic data. These synthetic materials, unlike mineral specimens that are well equilibrated, show no Si/P/S ordering and conform to P63/m symmetry. Phosphate-rich ellestadites where 0 ≤ x ≤ 1 show chemical stability towards Toxicity Characterization Leaching Procedure (TCLP) testing and are potential immobilization matrices for mixed toxic metal wastes.

  2. A Brine Shrimp Bioassay for Measuring Toxicity and Remediation of Chemicals

    NASA Astrophysics Data System (ADS)

    Lieberman, Marya

    1999-12-01

    A bioassay using Artemia franciscana (brine shrimp) was adapted to measure the toxicity of household chemicals. One project is described in which students collect dose-response curves for seven commercial flea-killing products. Next, groups of students researched the insecticidal ingredients of the flea products. On the basis of the structures of the active ingredients, they chose remediation methods to make the flea product less toxic to brine shrimp; procedures included copper-catalyzed hydrolysis, adsorption onto activated charcoal, bleach treatment, and photodegradation. No special equipment or supplies are necessary for the bioassay other than the brine shrimp eggs, which can be obtained at any aquarium store.

  3. Environmental phototoxicity: Solar ultraviolet radiation affects the toxicity of natural and man-made chemicals

    SciTech Connect

    Larson, R.A.; Berenbaum, M.R. )

    1988-04-01

    Ultraviolet radiation appears to be toxic to all forms of unpigmented living cells, including bacteria, protozoa, nematodes, arthropods, fish, birds, and mammals. In addition to the direct absorption of solar energy by cellular constituents, toxicity may occur because of the absorption of sunlight by xenobiotics (or by naturally occurring compounds outside the target cell); these may be converted by light or by subsequent light-promoted reactions that induce cellular damage. This article describes the phototoxicity of photodynamic dyes, light-activated synthetic herbicides, petroleum and its constituents, and naturally occurring chemicals from plants. Detoxification mechanisms are also discussed.

  4. Nonclinical reproductive toxicity testing requirements for drugs, pesticides, and industrial chemicals in India and China.

    PubMed

    Rao, K S; Dong, Jing

    2013-01-01

    India and China have booming chemical, agrochemical, and pharmaceutical industries. Both countries also represent expanding markets for foreign chemical and healthcare companies. All such products require reproductive toxicity testing before marketing. The ICH testing guidelines for medicinal products are not applicable in China and India. Nonetheless, reproductive toxicity studies designed and run to ICH principles are generally acceptable for submission. The Chinese guidelines take into consideration traditional Chinese medicines, which are usually mixtures. Likewise, the specific recommendations of India and China for the reproductive toxicity testing of chemicals and pesticides differ from those of the OECD and the USEPA. Again, studies performed in accordance with internationally recognized principles are usually acceptable for submission in both countries. The Chinese guideline for the reproductive toxicity testing of agrochemicals is currently under revision; the new version is expected to resemble more closely the requirements of the OECD and the USEPA. As a member of the OECD, India has conducted Good Laboratory Practice (GLP) inspection, accreditation, and monitoring activities since 2004. China has made several attempts to join the Council Decisions on Mutual Acceptance of Data in the Assessment of Chemicals since 2005. Currently 47 laboratories in China have been certified by the national GLP authorities. Several laboratories in China have also been recently been certified by OECD member countries as GLP compliant. In India, there are currently 23 GLP-Certified laboratories; about six of these are also AALAC accredited. The specific study designs specified in the guidelines of China and India for reproductive toxicity studies are described in detail in this chapter. PMID:23138892

  5. Predicting acute aquatic toxicity of structurally diverse chemicals in fish using artificial intelligence approaches.

    PubMed

    Singh, Kunwar P; Gupta, Shikha; Rai, Premanjali

    2013-09-01

    The research aims to develop global modeling tools capable of categorizing structurally diverse chemicals in various toxicity classes according to the EEC and European Community directives, and to predict their acute toxicity in fathead minnow using set of selected molecular descriptors. Accordingly, artificial intelligence approach based classification and regression models, such as probabilistic neural networks (PNN), generalized regression neural networks (GRNN), multilayer perceptron neural network (MLPN), radial basis function neural network (RBFN), support vector machines (SVM), gene expression programming (GEP), and decision tree (DT) were constructed using the experimental toxicity data. Diversity and non-linearity in the chemicals' data were tested using the Tanimoto similarity index and Brock-Dechert-Scheinkman statistics. Predictive and generalization abilities of various models constructed here were compared using several statistical parameters. PNN and GRNN models performed relatively better than MLPN, RBFN, SVM, GEP, and DT. Both in two and four category classifications, PNN yielded a considerably high accuracy of classification in training (95.85 percent and 90.07 percent) and validation data (91.30 percent and 86.96 percent), respectively. GRNN rendered a high correlation between the measured and model predicted -log LC50 values both for the training (0.929) and validation (0.910) data and low prediction errors (RMSE) of 0.52 and 0.49 for two sets. Efficiency of the selected PNN and GRNN models in predicting acute toxicity of new chemicals was adequately validated using external datasets of different fish species (fathead minnow, bluegill, trout, and guppy). The PNN and GRNN models showed good predictive and generalization abilities and can be used as tools for predicting toxicities of structurally diverse chemical compounds.

  6. Characterization of ZnS thin films synthesized through a non-toxic precursors chemical bath

    SciTech Connect

    Rodríguez, C.A.; Sandoval-Paz, M.G.; Cabello, G.; Flores, M.; Fernández, H.; Carrasco, C.

    2014-12-15

    Highlights: • High quality ZnS thin films have been deposited by chemical bath deposition technique from a non-toxic precursor’s solution. • Nanocrystalline ZnS thin films with large band gap energy were synthesized without using ammonia. • Evidence that the growing of the thin films is carried out by means of hydroxide mechanism was found. • The properties of these ZnS thin films are similar and in some cases better than the corresponding ones produced using toxic precursors such as ammonia. - Abstract: In solar cells, ZnS window layer deposited by chemical bath technique can reach the highest conversion efficiency; however, precursors used in the process normally are materials highly volatile, toxic and harmful to the environment and health (typically ammonia and hydrazine). In this work the characterization of ZnS thin films deposited by chemical bath in a non-toxic alkaline solution is reported. The effect of deposition technique (growth in several times) on the properties of the ZnS thin film was studied. The films exhibited a high percentage of optical transmission (greater than 80%); as the deposition time increased a decreasing in the band gap values from 3.83 eV to 3.71 eV was observed. From chemical analysis, the presence of ZnS and Zn(OH){sub 2} was identified and X-ray diffraction patterns exhibited a clear peak corresponding to ZnS hexagonal phase (1 0 3) plane, which was confirmed by electron diffraction patterns. From morphological studies, compact samples with well-defined particles, low roughness, homogeneous and pinhole-free in the surface were observed. From obtained results, it is evident that deposits of ZnS–CBD using a non-toxic solution are suitable as window layer for TFSC.

  7. Interpreting chemical compositions of small scale basaltic systems: A review

    NASA Astrophysics Data System (ADS)

    McGee, Lucy E.; Smith, Ian E. M.

    2016-10-01

    Small scale basaltic magmatic systems occur in all of the major tectonic environments of planet Earth and are characteristically expressed at the Earth's surface as fields of small monogenetic cones. The chemical compositions of the materials that make up these cones reflect processes of magma generation and differentiation that occur in their plumbing system. The volumes of magmas involved are very small and significantly their compositional ranges reveal remarkably complex processes which are overwhelmed or homogenized in larger scale systems. Commonly, compositions are basaltic, alkalic and enriched in light rare earth elements and large ion lithophile elements, although the spectrum extends from highly enriched nephelinites to subalkalic and tholeiitic basalts. Isotopic analyses of rocks from volcanic fields almost always display compositions which can only be explained by the interaction of two or more mantle sources. Ultimately their basaltic magmas originate by small scale melting of mantle sources. Compositional variety is testament to melting processes at different depths, a range of melting proportions, a heterogeneous source and fractionation, magma mixing and assimilation within the plumbing system that brings magmas to the surface. The fact that such a variety of compositions is preserved in a single field shows that isolation of individual melting events and their ascent is an important and possibly defining feature of monogenetic volcanism, as well as the window their chemical behavior provides into the complex process of melt generation and extraction in the Earth's upper mantle.

  8. Changes of chemical chronic toxicity to Daphnia magna under different food regimes.

    PubMed

    Pavlaki, Maria D; Ferreira, Abel L G; Soares, Amadeu M V M; Loureiro, Susana

    2014-11-01

    In aquatic ecosystems several stressors may act together and affect the life traits of organisms. Pesticide runoffs are usually associated with high inputs of organic matter and depletion of oxygen in aquatic systems. This study aimed at combining anthropogenic stress (chemicals) and natural stress (food availability) and evaluates their joint effect to the life traits of Daphnia magna. The neonicotinoid insecticide imidacloprid and the heavy metal nickel chloride were used and a 21 d chronic test was carried out to obtain reproduction and growth data. The conceptual model Independent action, usually used for assessing response patterns in chemical mixtures, was used for data interpretation. Results showed an increase in the reproduction and growth pattern of D. magna as food levels increased. Both chemicals significantly impaired the reproduction as well as the somatic growth of the organism while the same happened with food concentrations lower than 3×10(5) cells/mL. It was also observed that food availability did not change the toxicity of imidacloprid and nickel chloride when food levels were higher than 3×10(5) cells/mL. When combined with low food levels, imidacloprid showed a slight increase in toxicity, showing that daphnids become more sensitive with reduced food availability, however in a non-significant way. However, toxicity of nickel appeared to be independent of the food level. Both chemicals induced mortality to the organisms exposed in the absence of food only at the end of the test.

  9. Lethal toxicity of industrial chemicals to early life stages of Tilapia guineensis.

    PubMed

    Ezemonye, L I N; Ogeleka, D F; Okieimen, F E

    2008-08-30

    The toxic effects of industrial chemicals on three early life stages of an economically important fish, Tilapia guineensis were investigated using the Organisation for Economic Cooperation and Development (OECD) # 203 recommended semi-static renewal bioassay. The assessment was necessary for the uncontrollable disposal of Neatex (liquid detergent) and Norust CR 486 (corrosion inhibitor) into the Niger Delta environment of Nigeria. The estimated 96-h LC(50) for 7-, 14- and 28-day-old fish in Norust CR 486 exposure was considered "more toxic" than Neatex in all life stages and was dependent on species age, exposure duration and environment. In the fresh water test, for Neatex and Norust CR 486 exposures for day 7, 14 and 28, the 96-h LC50 were 8.79, 17.10 and 82.42 mg/l and 5.55, 13.58 and 20.21 mg/l, respectively. In the brackish test, 15.42 and 46.52 mg/l, not determined (ND) and 7.35, 13.95 and 24.50mg/l were obtained. Differential toxicity was observed in the fresh and brackish water fish for the two chemicals and controls at p<0.05. The high sensitivity of the 7-day-old test organisms to both chemicals provides a rationale for regulatory surveillance and monitoring of both chemicals in the fragile Niger Delta environment. PMID:18262353

  10. Development of chemical vapor composites, CVC materials. Final report

    SciTech Connect

    1998-10-05

    Industry has a critical need for high-temperature operable ceramic composites that are strong, non-brittle, light weight, and corrosion resistant. Improvements in energy efficiency, reduced emissions and increased productivity can be achieved in many industrial processes with ceramic composites if the reaction temperature and pressure are increased. Ceramic composites offer the potential to meet these material requirements in a variety of industrial applications. However, their use is often restricted by high cost. The Chemical Vapor composite, CVC, process can reduce the high costs and multiple fabrication steps presently required for ceramic fabrication. CVC deposition has the potential to eliminate many difficult processing problems and greatly increase fabrication rates for composites. With CVC, the manufacturing process can control the composites` density, microstructure and composition during growth. The CVC process: can grow or deposit material 100 times faster than conventional techniques; does not require an expensive woven preform to infiltrate; can use high modulus fibers that cannot be woven into a preform; can deposit composites to tolerances of less than 0.025 mm on one surface without further machining.

  11. Magnetometric evaluation of toxicities of chemicals to the lungs and cells

    PubMed Central

    Aizawa, Yoshiharu

    2010-01-01

    Because the lungs are exposed to airborne hazardous materials, alveolar macrophages (AMs) play a major role in defending against the exposure to various noxious chemical substances. In this study, we reviewed magnetometric investigations of the effects of various chemicals on the lungs and AMs. Magnetometry, using magnetite as an indicator, was used to evaluate the effects of certain chemicals on the lung and AMs. A rapid decrease of the remanent magnetic field after the cessation of external magnetization, a phenomenon called relaxation, was impaired when the lungs and macrophages were exposed to toxic substances. The delayed in vivo relaxation observed in the lungs exposed to magnetite and gallium arsenide was almost identical to the in vitro relaxation observed in the AMs exposed to the same materials. Delayed relaxation was observed in the AMs exposed to silica dust; various fibers, such as chrysotile and some man-made mineral fibers; and toxic arsenic and cadmium compounds. The extracellular release of lactate dehydrogenase activity was found in the AMs exposed to the chemicals. Relaxation is attributed to the cytoskeleton-driven rotation of phagosomes containing magnetite. While the exact mechanism of delayed relaxation due to exposure to harmful chemicals remains to be clarified, cell magnetometry appears to be useful for the safety screening of chemical substances. PMID:21432545

  12. Magnetometric evaluation of toxicities of chemicals to the lungs and cells.

    PubMed

    Aizawa, Yoshiharu; Kudo, Yuichiro

    2010-07-01

    Because the lungs are exposed to airborne hazardous materials, alveolar macrophages (AMs) play a major role in defending against the exposure to various noxious chemical substances. In this study, we reviewed magnetometric investigations of the effects of various chemicals on the lungs and AMs. Magnetometry, using magnetite as an indicator, was used to evaluate the effects of certain chemicals on the lung and AMs. A rapid decrease of the remanent magnetic field after the cessation of external magnetization, a phenomenon called relaxation, was impaired when the lungs and macrophages were exposed to toxic substances. The delayed in vivo relaxation observed in the lungs exposed to magnetite and gallium arsenide was almost identical to the in vitro relaxation observed in the AMs exposed to the same materials. Delayed relaxation was observed in the AMs exposed to silica dust; various fibers, such as chrysotile and some man-made mineral fibers; and toxic arsenic and cadmium compounds. The extracellular release of lactate dehydrogenase activity was found in the AMs exposed to the chemicals. Relaxation is attributed to the cytoskeleton-driven rotation of phagosomes containing magnetite. While the exact mechanism of delayed relaxation due to exposure to harmful chemicals remains to be clarified, cell magnetometry appears to be useful for the safety screening of chemical substances.

  13. The underlying toxicological mechanism of chemical mixtures: A case study on mixture toxicity of cyanogenic toxicants and aldehydes to Photobacterium phosphoreum

    SciTech Connect

    Tian, Dayong; Lin, Zhifen; Zhou, Xianghong; Yin, Daqiang

    2013-10-15

    Intracellular chemical reaction of chemical mixtures is one of the main reasons that cause synergistic or antagonistic effects. However, it still remains unclear what the influencing factors on the intracellular chemical reaction are, and how they influence on the toxicological mechanism of chemical mixtures. To reveal this underlying toxicological mechanism of chemical mixtures, a case study on mixture toxicity of cyanogenic toxicants and aldehydes to Photobacterium phosphoreum was employed, and both their joint effects and mixture toxicity were observed. Then series of two-step linear regressions were performed to describe the relationships between joint effects, the expected additive toxicities and descriptors of individual chemicals (including concentrations, binding affinity to receptors, octanol/water partition coefficients). Based on the quantitative relationships, the underlying joint toxicological mechanisms were revealed. The result shows that, for mixtures with their joint effects resulting from intracellular chemical reaction, their underlying toxicological mechanism depends on not only their interaction with target proteins, but also their transmembrane actions and their concentrations. In addition, two generic points of toxicological mechanism were proposed including the influencing factors on intracellular chemical reaction and the difference of the toxicological mechanism between single reactive chemicals and their mixtures. This study provided an insight into the understanding of the underlying toxicological mechanism for chemical mixtures with intracellular chemical reaction. - Highlights: • Joint effects of nitriles and aldehydes at non-equitoxic ratios were determined. • A novel descriptor, ligand–receptor interaction energy (E{sub binding}), was employed. • Quantitative relationships for mixtures were developed based on a novel descriptor. • The underlying toxic mechanism was revealed based on quantitative relationships. • Two

  14. Quantification of aerosol chemical composition using continuous single particle measurements

    NASA Astrophysics Data System (ADS)

    Jeong, C.-H.; McGuire, M. L.; Godri, K. J.; Slowik, J. G.; Rehbein, P. J. G.; Evans, G. J.

    2011-01-01

    Mass concentrations of particulate matter (PM) chemical components were determined from data for 0.3 to 3.0 μm particles measured by an Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) data at an urban and rural site. Hourly-averaged concentrations of nitrate, sulphate, ammonium, organic carbon, and elemental carbon, estimated based on scaled ATOFMS peak intensities of corresponding ion marker species, were compared with collocated chemical composition measurements by an Aerosol Mass Spectrometer (AMS), a Gas-Particle Ion Chromatograph (GPIC), and a Sunset Lab field OCEC analyzer. The highest correlation was found for nitrate, with correlation coefficients (Pearson r) of 0.89 and 0.85 at the urban and rural sites, respectively. ATOFMS mass calibration factors, determined for the urban site, were used to calculate mass concentrations of the major PM chemical components at the rural site. Mass reconstruction using this ATOFMS based composition data agreed very well with the total PM mass measured at the rural site. Size distributions of the ten main types of particles were resolved for the rural site and the mass composition of each particle type was determined in terms of sulphate, nitrate, ammonium, organic carbon and elemental carbon. This is the first study to estimate hourly mass concentrations of individual aerosol components and the mass composition of individual particle-types based on ATOFMS single particle measurements.

  15. Toxicity of cigarette butts, and their chemical components, to marine and freshwater fish

    PubMed Central

    Gersberg, Richard M; Watanabe, Kayo; Rudolph, John; Stransky, Chris; Novotny, Thomas E

    2011-01-01

    Background Cigarette butts are the most common form of litter, as an estimated 4.5 trillion cigarette butts are thrown away every year worldwide. Many chemical products are used during the course of growing tobacco and manufacturing cigarettes, the residues of which may be found in cigarettes prepared for consumption. Additionally, over 4000 chemicals may also be introduced to the environment via cigarette particulate matter (tar) and mainstream smoke. Methods Using US Environmental Protection Agency standard acute fish bioassays, cigarette butt-derived leachate was analysed for aquatic toxicity. Survival was the single endpoint and data were analysed using Comprehensive Environmental Toxicity Information System to identify the LC50 of cigarette butt leachate to fish. Results The LC50 for leachate from smoked cigarette butts (smoked filter + tobacco) was approximately one cigarette butt/l for both the marine topsmelt (Atherinops affinis) and the freshwater fathead minnow (Pimephales promelas). Leachate from smoked cigarette filters (no tobacco), was less toxic, with LC50 values of 1.8 and 4.3 cigarette butts/l, respectively for both fish species. Unsmoked cigarette filters (no tobacco) were also found to be toxic, with LC50 values of 5.1 and 13.5 cigarette butts/l, respectively, for both fish species. Conclusion Toxicity of cigarette butt leachate was found to increase from unsmoked cigarette filters (no tobacco) to smoked cigarette filters (no tobacco) to smoked cigarette butts (smoked filter + tobacco). This study represents the first in the literature to investigate and affirm the toxicity of cigarette butts to fish, and will assist in assessing the potential ecological risks of cigarette butts to the aquatic environment. PMID:21504921

  16. Surface chemical composition analysis of heat-treated bamboo

    NASA Astrophysics Data System (ADS)

    Meng, Fan-dan; Yu, Yang-lun; Zhang, Ya-mei; Yu, Wen-ji; Gao, Jian-min

    2016-05-01

    In this study, the effect of heat treatment on the chemical composition of bamboo slivers was studied. The chemical properties of the samples were examined by chemical analysis. Results showed a decrease in the contents of holocellulose and α-cellulose, as well as an increase in the contents of lignin and extractives. Changes in the chemical structure of bamboo components were analyzed by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). FTIR spectroscopy results indicated that hemicellulose contents decrease, whereas lignin contents increase after heat treatment. Ester formation linked to lignin decreased the hygroscopicity of the bamboo samples and consequently improved their dimensional stability and durability. XPS spectroscopy results showed that hemicelluloses and celluloses are relatively more sensitive to the heating process than lignin. As a consequence, hemicellulose and cellulose contents decreased, whereas lignin contents increased during heat treatment. The results obtained in this study provide useful information for the future utilization of heat-treated bamboo.

  17. Composition and placement process for oil field chemicals

    SciTech Connect

    Cantu, L.A.; Yost, M.E.

    1991-01-22

    This patent describes a process for the continuous release of an oil field chemical within a subterranean hydrocarbon bearing formation or wellbore penetrating such formation. It comprises placing the oil field chemical in a polymeric microcapsule; dispersing such polymeric microcapsules; introducing the wellbore fluid containing the microcapsules into a well bore or subterranean formation through a wellbore; then allowing water and temperature at formation conditions to degrade; continuously releasing the chemical from the degraded microcapsules. This patent describes a composition comprising an oil field chemical incorporated in a polymeric microcapsule comprising the condensation product of hydroxyacetic acid monomer or hydroxyacetic acid co-condensed with up to 15 percent by weight of other hydroxy-, carboxylic acid-, or hydroxycarboxylic acid- containing moieties. The product has a number average molecular weight of from about 200 to about 4000.

  18. Date fruit: chemical composition, nutritional and medicinal values, products.

    PubMed

    Tang, Zhen-Xing; Shi, Lu-E; Aleid, Salah M

    2013-08-15

    Date fruit has served as a staple food in the Arab world for centuries. Worldwide production of date fruit has increased almost threefold over the last 40 years, reaching 7.68 million tons in 2010. Date fruit can provide many essential nutrients and potential health benefits to the consumer. Date fruit goes through four ripening stages named kimri, khalal, rutab and tamer. The main chemical components of date fruit include carbohydrates, dietary fibre, enzymes, protein, fat, minerals, vitamins, phenolic acids and carotenoids. The chemical composition of date fruit varies according to ripening stage, cultivar, growing environment, postharvest conditions, etc. The nutritional and medicinal activities of date fruit are related to its chemical composition. Many studies have shown that date fruit has antioxidant, antimutagenic, anti-inflammatory, gastroprotective, hepatoprotective, nephroprotective, anticancer and immunostimulant activities. Various date fruit-based products such as date syrup, date paste, date juice and their derived products are available. Date by-products can be used as raw materials for the production of value-added products such as organic acids, exopolysaccharides, antibiotics, date-flavoured probiotic-fermented dairy produce, bakery yeasts, etc. In this paper the chemical composition and nutritional and medicinal values of date fruit as well as date fruit-based products are reviewed.

  19. Impact of environmentally based chemical hardness on uranium speciation and toxicity in six aquatic species.

    PubMed

    Goulet, Richard R; Thompson, Patsy A; Serben, Kerrie C; Eickhoff, Curtis V

    2015-03-01

    Treated effluent discharge from uranium (U) mines and mills elevates the concentrations of U, calcium (Ca), magnesium (Mg), and sulfate (SO4 (2-) ) above natural levels in receiving waters. Many investigations on the effect of hardness on U toxicity have been experiments on the combined effects of changes in hardness, pH, and alkalinity, which do not represent water chemistry downstream of U mines and mills. Therefore, more toxicity studies with water chemistry encountered downstream of U mines and mills are necessary to support predictive assessments of impacts of U discharge to the environment. Acute and chronic U toxicity laboratory bioassays were realized with 6 freshwater species in waters of low alkalinity, circumneutral pH, and a range of chemical hardness as found in field samples collected downstream of U mines and mills. In laboratory-tested waters, speciation calculations suggested that free uranyl ion concentrations remained constant despite increasing chemical hardness. When hardness increased while pH remained circumneutral and alkalinity low, U toxicity decreased only to Hyalella azteca and Pseudokirchneriella subcapitata. Also, Ca and Mg did not compete with U for the same uptake sites. The present study confirms that the majority of studies concluding that hardness affected U toxicity were in fact studies in which alkalinity and pH were the stronger influence. The results thus confirm that studies predicting impacts of U downstream of mines and mills should not consider chemical hardness. Environ Toxicol Chem 2015;34:562-574. © 2014 The Authors. Published by Wiley Periodicals, Inc. on behalf of SETAC.

  20. Impact of environmentally based chemical hardness on uranium speciation and toxicity in six aquatic species.

    PubMed

    Goulet, Richard R; Thompson, Patsy A; Serben, Kerrie C; Eickhoff, Curtis V

    2015-03-01

    Treated effluent discharge from uranium (U) mines and mills elevates the concentrations of U, calcium (Ca), magnesium (Mg), and sulfate (SO4 (2-) ) above natural levels in receiving waters. Many investigations on the effect of hardness on U toxicity have been experiments on the combined effects of changes in hardness, pH, and alkalinity, which do not represent water chemistry downstream of U mines and mills. Therefore, more toxicity studies with water chemistry encountered downstream of U mines and mills are necessary to support predictive assessments of impacts of U discharge to the environment. Acute and chronic U toxicity laboratory bioassays were realized with 6 freshwater species in waters of low alkalinity, circumneutral pH, and a range of chemical hardness as found in field samples collected downstream of U mines and mills. In laboratory-tested waters, speciation calculations suggested that free uranyl ion concentrations remained constant despite increasing chemical hardness. When hardness increased while pH remained circumneutral and alkalinity low, U toxicity decreased only to Hyalella azteca and Pseudokirchneriella subcapitata. Also, Ca and Mg did not compete with U for the same uptake sites. The present study confirms that the majority of studies concluding that hardness affected U toxicity were in fact studies in which alkalinity and pH were the stronger influence. The results thus confirm that studies predicting impacts of U downstream of mines and mills should not consider chemical hardness. Environ Toxicol Chem 2015;34:562-574. © 2014 The Authors. Published by Wiley Periodicals, Inc. on behalf of SETAC. PMID:25475484

  1. QSTR modeling for qualitative and quantitative toxicity predictions of diverse chemical pesticides in honey bee for regulatory purposes.

    PubMed

    Singh, Kunwar P; Gupta, Shikha; Basant, Nikita; Mohan, Dinesh

    2014-09-15

    Pesticides are designed toxic chemicals for specific purposes and can harm nontarget species as well. The honey bee is considered a nontarget test species for toxicity evaluation of chemicals. Global QSTR (quantitative structure-toxicity relationship) models were established for qualitative and quantitative toxicity prediction of pesticides in honey bee (Apis mellifera) based on the experimental toxicity data of 237 structurally diverse pesticides. Structural diversity of the chemical pesticides and nonlinear dependence in the toxicity data were evaluated using the Tanimoto similarity index and Brock-Dechert-Scheinkman statistics. Probabilistic neural network (PNN) and generalized regression neural network (GRNN) QSTR models were constructed for classification (two and four categories) and function optimization problems using the toxicity end point in honey bees. The predictive power of the QSTR models was tested through rigorous validation performed using the internal and external procedures employing a wide series of statistical checks. In complete data, the PNN-QSTR model rendered a classification accuracy of 96.62% (two-category) and 95.57% (four-category), while the GRNN-QSTR model yielded a correlation (R(2)) of 0.841 between the measured and predicted toxicity values with a mean squared error (MSE) of 0.22. The results suggest the appropriateness of the developed QSTR models for reliably predicting qualitative and quantitative toxicities of pesticides in honey bee. Both the PNN and GRNN based QSTR models constructed here can be useful tools in predicting the qualitative and quantitative toxicities of the new chemical pesticides for regulatory purposes.

  2. Correlation of the five test methods to assess chemical toxicity and relation to physical properties

    SciTech Connect

    Yoshioka, Y.; Ose, Y.; Sato, T.

    1986-08-01

    Biological tests using Orizias latipes (LC50 and oxygen uptake test), Moina macrocopa (LC50), and Dugesia japonica (head regeneration test and LC50) were carried out in order to clarify the mutual relationship of these test methods. The oxygen uptake rate of O. latipes was not effective to assess chemical toxicity. Adding the results of the growth inhibition test of Tetrahymena pyriformis (Yoshioka, Y., Ose, Y., and Sato, T. (1985). Sci. Total Environ. 43, 149-157), the correlation coefficients between each two test methods were calculated. The test results except EC50 and LC50 of D. japonica showed a good relation to each other. We determined the solubility and the n-octanol/water partition coefficient (P) of some chemicals used in the test. Log P interpreted the toxicity in mol/liter unit but not in mg/liter. Solubility was not a useful descripter neither in mol/liter nor in mg/liter unit.

  3. A Novel Energy-Efficient Plasma Chemical Process for the Destruction of Volatile Toxic Compounds

    SciTech Connect

    Pinnaduwage, Lal A.; Ma, Cheng-YU

    1999-06-01

    Removal of low-concentrations (below several percent) of volatile toxic compounds (VTCs) from contaminated air streams is encountered at DOE waste sites in two instances: (i) Off-gases resulting from air-stripping of contaminated soil and water. (ii) Effluent from the incineration of highly-concentrated combustible hazardous wastes The objective of our research program is to develop a novel plasma chemical process for the destruction of VTC's in low-concentration waste streams.

  4. A Novel Energy Efficient Plasma Chemical Process for the Destruction of Volatile Toxic Compounds

    SciTech Connect

    Pinnaduwage, Lal A.

    2000-06-01

    The objective is to develop a novel plasma chemical process for the destruction of low concentrations (below several percent) of toxic volatile compounds from contaminated air streams. Such contaminated air streams are encountered in air stripping of highly-contaminated water and soil, and also in the incineration of combustible hazardous wastes. Our technique is based on the efficient dissociation of molecules via enhanced electron attachment to highly-excited states of the molecules produced in a glow discharge.

  5. Low molecular weight chemicals, hypersensitivity, and direct toxicity: the acid anhydrides.

    PubMed Central

    Venables, K M

    1989-01-01

    The acid anhydrides are a group of reactive chemicals used widely in alkyd and epoxy resins. The major hazards to health are mucosal and skin irritation and sensitisation of the respiratory tract. Most occupational asthma caused by acid anhydrides appears to be immunologically mediated. Immunological mechanisms have been proposed to explain an influenza-like syndrome and pulmonary haemorrhage, but direct toxicity may also be important in the aetiology of these conditions. PMID:2653411

  6. Acute toxicity of firefighting chemical formulations to four life stages of fathead minnow

    USGS Publications Warehouse

    Gaikowski, Mark P.; Hamilton, Steve J.; Buhl, Kevin J.; McDonald, Susan F.; Summers, Cliff H.

    1996-01-01

    Laboratory studies were conducted with four early life stages of fathead minnow,Pimephales promelas,to determine the acute toxicity of five firefighting chemical formulations in standardized soft and hard water. Egg, fry, 30-day posthatch, and 60-day posthatch life stages were tested with three fire retardants (Fire-Trol GTS-R, Fire-Trol LCG-R, and Phos-Chek D75-F) and two fire-suppressant foams (Phos-Chek WD-881 and Ansul Silv-Ex). Fry were generally the most sensitive life stage tested, whereas the eggs were the least sensitive life stage. Formulation toxicity was greater in hard water than in soft water for all life stages tested. Fire-suppressant foams were more toxic than the fire retardants. The 96-hr LC50s derived for fathead minnows were rank ordered from the most toxic to the least toxic formulation as follows: Phos-Chek WD-881 (13a??32 mg/liter) > Silv-Ex (19a??32 mg/liter) > Fire-Trol GTS-R (135a??787 mg/liter) > Phos-Chek D75-F (168a??2250 mg/liter) > Fire-Trol LCG-R (519a??6705 mg/liter) (ranges are the lowest and highest 96-hr LC50for each formulation). (C) 1996 Academic Press, Inc.

  7. Acute toxicity of eight oil spill response chemicals to temperate, boreal, and Arctic species.

    PubMed

    Hansen, Bjørn Henrik; Altin, Dag; Bonaunet, Kristin; Overjordet, Ida Beathe

    2014-01-01

    The objectives of this study were to (1) determine the acute toxicity of selected shoreline washing agents (SWA) and dispersants, and (2) assess interspecies differences in sensitivity to the products. Eight shoreline washing agents (Hela saneringsvæske, Bios, Bioversal, Absorrep K212, and Corexit 9580) and chemical dispersants (Corexit 9500, Dasic NS, and Gamlen OD4000) were tested on five marine species, algae Skeletonema costatum, planktonic copepod species Acartia tonsa (temperate species), Calanus finmarchicus (boreal species) and Calanus glacialis (Arctic species), and benthic amphipod Corophium volutator. For most products, A. tonsa was the most sensitive species, whereas C. volutator was the least sensitive; however, these species were exposed through different media (water/sediment). In general, all copepod species displayed a relatively similar sensitivity to all products. However, A. tonsa was somewhat more sensitive than other copepods to most of the tested products. Thus, A. tonsa appears to be a candidate species for boreal and Arctic copepods for acute toxicity testing, and data generated on this species may be used as to provide conservative estimates. The benthic species (C. volutator) had a different sensitivity pattern relative to pelagic species, displaying higher sensitivity to solvent-based SWA than to water-based SWA. Comparing product toxicity, the dispersants were in general most toxic while the solvent-based SWA were least toxic to pelagic species. PMID:24754387

  8. Acute toxicity of eight oil spill response chemicals to temperate, boreal, and Arctic species.

    PubMed

    Hansen, Bjørn Henrik; Altin, Dag; Bonaunet, Kristin; Overjordet, Ida Beathe

    2014-01-01

    The objectives of this study were to (1) determine the acute toxicity of selected shoreline washing agents (SWA) and dispersants, and (2) assess interspecies differences in sensitivity to the products. Eight shoreline washing agents (Hela saneringsvæske, Bios, Bioversal, Absorrep K212, and Corexit 9580) and chemical dispersants (Corexit 9500, Dasic NS, and Gamlen OD4000) were tested on five marine species, algae Skeletonema costatum, planktonic copepod species Acartia tonsa (temperate species), Calanus finmarchicus (boreal species) and Calanus glacialis (Arctic species), and benthic amphipod Corophium volutator. For most products, A. tonsa was the most sensitive species, whereas C. volutator was the least sensitive; however, these species were exposed through different media (water/sediment). In general, all copepod species displayed a relatively similar sensitivity to all products. However, A. tonsa was somewhat more sensitive than other copepods to most of the tested products. Thus, A. tonsa appears to be a candidate species for boreal and Arctic copepods for acute toxicity testing, and data generated on this species may be used as to provide conservative estimates. The benthic species (C. volutator) had a different sensitivity pattern relative to pelagic species, displaying higher sensitivity to solvent-based SWA than to water-based SWA. Comparing product toxicity, the dispersants were in general most toxic while the solvent-based SWA were least toxic to pelagic species.

  9. Review of the toxicity of chemical mixtures: Theory, policy, and regulatory practice.

    PubMed

    McCarty, L S; Borgert, C J

    2006-07-01

    An analysis of current mixture theory, policy, and practice was conducted by examining standard reference texts, regulatory guidance documents, and journal articles. Although this literature contains useful theoretical concepts, clear definitions of most terminology, and well developed protocols for study design and statistical analysis, no general theoretical basis for the mechanisms and interactions of mixture toxicity could be discerned. There is also a poor understanding of the relationship between exposure-based and internal received dose metrics. This confounds data interpretation and limits reliable determinations of the nature and extent of additivity. The absence of any generally accepted classification scheme for either modes/mechanisms of toxic action or of mechanisms of toxicity interactions is problematic as it produces a cycle in which research and policy are interdependent and mutually limiting. Current regulatory guidance depends heavily on determination of toxicological similarity concluded from the presence of a few prominent constituents, assumed from a common toxicological effect, or presumed from an alleged similar toxic mode/mechanism. Additivity, or the lack of it, is largely based on extrapolation of existing knowledge for single chemicals in this context. Thus, regulatory risk assessment protocols lack authoritative theoretical underpinnings, creating substantial uncertainty. Development of comprehensive classification schemes for modes/mechanisms of toxic action and mechanisms of interaction is needed to ensure a sound theoretical foundation for mixture-related regulatory activity and provide a firm basis for iterative hypothesis development and experimental testing.

  10. Modification of the Neubauer technique to assess toxicity of hazardous chemicals in soils

    SciTech Connect

    Thomas, J.M.; Cline, J.F.

    1985-01-01

    The Neubauer technique was modified to provide a sensitive and economical phytoassay for soils and surface waters obtained from a chemical waste site. Use of individual plastic enclosures allowed safe handling and disposal over the course of our experiments. Laboratory tests showed that water from a holding basin was toxic to wheat plants at dilutions of less than 1% and that our modified Neubauer technique produced results compatible with both pot culture and the standard Neubauer test. Further testing of several inorganic constituents of the basin water pointed to an organic toxicant, even though the original water contained high levels of sodium, copper and other elements. The results of testing 26 samples from an abandoned waste pond were negative insofar as toxicity to wheat and lettuce seeds, whereas samples from an abandoned ditch allowed us to determine areal toxicity as well as toxicity as a function of depth and suggested that more than one species should be tested. 10 references, 2 figures, 5 tables.

  11. Chemical and isotopic compositions in acid residues from various meteorites

    NASA Technical Reports Server (NTRS)

    Kano, N.; Yamakoshi, K.; Matsuzaki, H.; Nogami, K.

    1993-01-01

    We are planning to carry out systematic isotopic investigations of Ru, Mg, etc., in primordial samples. The investigations will be pursued in the context of a study of the pre-history of the solar system. It is hoped that the study will yield direct evidence for processes of nucleosynthesis in the pre-solar stage and detection of extinct radioactive nuclides. In this paper, we present the results of chemical compositions of acid residues obtained from three types of meteorites: Canyon Diablo (IA), Allende (CV3), and Nuevo Mercuro (H5); and the preliminary results of Ru isotopic compositions.

  12. Data gaps in toxicity testing of chemicals allowed in food in the United States.

    PubMed

    Neltner, Thomas G; Alger, Heather M; Leonard, Jack E; Maffini, Maricel V

    2013-12-01

    In the United States, chemical additives cannot be used in food without an affirmative determination that their use is safe by FDA or additive manufacturer. Feeding toxicology studies designed to estimate the amount of a chemical additive that can be eaten safely provide the most relevant information. We analyze how many chemical additives allowed in human food have feeding toxicology studies in three toxicological information sources including the U.S. Food and Drug Administration's (FDA) database. Less than 38% of FDA-regulated additives have a published feeding study. For chemicals directly added to food, 21.6% have feeding studies necessary to estimate a safe level of exposure and 6.7% have reproductive or developmental toxicity data in FDA's database. A program is needed to fill these significant knowledge gaps by using in vitro and in silico methods complemented with targeted in vivo studies to ensure public health is protected.

  13. Comparison of different physico-chemical methods for the removal of toxicants from landfill leachate.

    PubMed

    Cotman, Magda; Gotvajn, Andreja Zgajnar

    2010-06-15

    Our work was focused on investigation of different treatment procedures for the removal of toxic fractions from a landfill leachate, because sometimes the existing treatment in biological sequencing batch reactor (SBR) is not efficient enough, leading to a hazardous environmental impact of the present persistent and toxic compounds. The efficiency of the procedures used was monitored by chemical analyses and two toxicity tests (activated sludge and Vibrio fischeri). The existing SBR (HRT=1.9 days) removed 46-78% of COD and 96-73% of NH(4)(+)-N. Experiments were conducted with three landfill leachate samples expressing significant difference in concentrations of pollutants and with low BOD(5)/COD ratio (0.06/0.01/0.03). The applied methods were air stripping, adsorption to activated carbon and zeolite clinoptilolite and Fenton oxidation. Air stripping at pH 11 was a viable treatment option for the removal of ammonia nitrogen (up to 94%) and reduction of toxicity to microorganisms. In the adsorption experiments in batch system with different concentration of PAC the most effective was the highest addition (50.0gL(-1)) where 63-92% of COD was removed followed by significant reduction in toxicity to V. fischeri. In the column experiments with clinoptilolite 45/93/100% of NH(4)(+)-N as well as 25/32/39% of COD removal was attained. The removal efficiency for metals followed the sequence Cr>Zn>Cd>Ni. The procedure with zeolite was the second most efficient one regarding reduction of toxicity to both organisms. Fenton oxidation at molar ratio Fe(2+):H(2)O(2)=1.0:10.0 assured 70-85% removal of COD but it only slightly reduced the toxicity.

  14. Monitoring and trace detection of hazardous waste and toxic chemicals using resonance Raman spectroscopy

    SciTech Connect

    Sedlacek, A.J. III; Dougherty, D.R.; Chen, C.L.

    1993-04-01

    Raman scattering is a coherent, inelastic, two-photon process, which shifts the frequency of an outgoing photon according to the vibrational structure of the irradiated species, thereby providing a unique fingerprint of the molecule. When involving an allowed electronic transition (resonance Raman), this scattering cross section can be enhanced by 10{sup 4} to 10{sup 6} and provides the basis for a viable technique that can monitor and detect trace quantities of hazardous wastes and toxic chemicals. Resonance Raman spectroscopy (RRS) possesses many of the ideal characteristics for monitoring and detecting of hazardous waste and toxic chemicals. Some of these traits are: (1) very high selectivity (chemical specific fingerprints); (2) independence from the excitation wavelength (ability to monitor in the solar blind region); (3) chemical mixture fingerprints are the sum of its individual components (no spectral cross-talk); (4) near independence of the Raman fingerprint to its physical state (very similar spectra for gas, liquid, solid and solutions -- either bulk or aerosols); and (5) insensitivity of the Raman signature to environmental conditions (no quenching). Data from a few chemicals will be presented which illustrate these features. In cases where background fluorescence accompanies the Raman signals, an effective frequency modulation technique has been developed, which can completely eliminate this interference.

  15. Monitoring and trace detection of hazardous waste and toxic chemicals using resonance Raman spectroscopy

    SciTech Connect

    Sedlacek, A.J. III; Dougherty, D.R.; Chen, C.L.

    1993-01-01

    Raman scattering is a coherent, inelastic, two-photon process, which shifts the frequency of an outgoing photon according to the vibrational structure of the irradiated species, thereby providing a unique fingerprint of the molecule. When involving an allowed electronic transition (resonance Raman), this scattering cross section can be enhanced by 10[sup 4] to 10[sup 6] and provides the basis for a viable technique that can monitor and detect trace quantities of hazardous wastes and toxic chemicals. Resonance Raman spectroscopy (RRS) possesses many of the ideal characteristics for monitoring and detecting of hazardous waste and toxic chemicals. Some of these traits are: (1) very high selectivity (chemical specific fingerprints); (2) independence from the excitation wavelength (ability to monitor in the solar blind region); (3) chemical mixture fingerprints are the sum of its individual components (no spectral cross-talk); (4) near independence of the Raman fingerprint to its physical state (very similar spectra for gas, liquid, solid and solutions -- either bulk or aerosols); and (5) insensitivity of the Raman signature to environmental conditions (no quenching). Data from a few chemicals will be presented which illustrate these features. In cases where background fluorescence accompanies the Raman signals, an effective frequency modulation technique has been developed, which can completely eliminate this interference.

  16. The prediction of toxic mode of action for environmental pollutants based on physico-chemical properties

    SciTech Connect

    Boxall, A.B.A. |; Watts, C.D.; Bresnen, G.M.; Dearden, J.C.; Scoffin, R.

    1995-12-31

    Aquatic ecosystems receive a wide range of potentially toxic contaminants. One approach to measure the environmental impact of these compounds is to perform costly and detailed experimental investigations. A quick and cost-effective alternative is to predict the likely effects of chemical contaminants using quantitative structure activity relationships (QSARs) which relate effects to chemical structure. One problem with the predictive approach is that QSARs can be established and used only for compounds with a common mode of toxic action. It is therefore important that a compound is assigned to the correct mode of action and that the correct QSAR is used. Two kinds of approach can be used to address this problem. In the first a compound is assigned to a class based on responses observed during experimental tests. The other approach uses chemical structural information e.g. the OECD method where compounds are classed as inert, less inert, reactive or specific acting based on chemical structure. The objective of this study was to determine whether compounds could be classified into one of the four OECD classes solely on the basis of their physico-chemical properties. Approximately 800 compounds were assigned to an OECD class and a range of properties were calculated. Discriminant analysis demonstrated that a large proportion of these compounds could be classified correctly based on two properties, namely a molecular connectivity index ({sup 2}{sub x}) and an electronic parameter (E{sub HOMO}).

  17. Chemical composition and medicinal significance of Fagonia cretica: a review.

    PubMed

    Qureshi, Huma; Asif, Saira; Ahmed, Haroon; Al-Kahtani, Hassan A; Hayat, Khizar

    2016-01-01

    Members of the family Zygophyllaceae are distributed in arid areas of the world and are traditionally used against various health insults ranging from skin lesions to lethal cancer. Fagonia cretica Linn. is a plant having novel compounds responsive in diseases that are still considered as incurable or are curable with serious side effects. Researchers, particularly of the Asian region elaborately studied the chemical composition and pharmacological activities of this plant. But further studies are still required to evaluate this plant in clinical trials in order to save humanity from synthetic chemical drugs yet disputed as 'friends or foe'. PMID:25921950

  18. Prediction of developmental chemical toxicity based on gene networks of human embryonic stem cells.

    PubMed

    Yamane, Junko; Aburatani, Sachiyo; Imanishi, Satoshi; Akanuma, Hiromi; Nagano, Reiko; Kato, Tsuyoshi; Sone, Hideko; Ohsako, Seiichiroh; Fujibuchi, Wataru

    2016-07-01

    Predictive toxicology using stem cells or their derived tissues has gained increasing importance in biomedical and pharmaceutical research. Here, we show that toxicity category prediction by support vector machines (SVMs), which uses qRT-PCR data from 20 categorized chemicals based on a human embryonic stem cell (hESC) system, is improved by the adoption of gene networks, in which network edge weights are added as feature vectors when noisy qRT-PCR data fail to make accurate predictions. The accuracies of our system were 97.5-100% for three toxicity categories: neurotoxins (NTs), genotoxic carcinogens (GCs) and non-genotoxic carcinogens (NGCs). For two uncategorized chemicals, bisphenol-A and permethrin, our system yielded reasonable results: bisphenol-A was categorized as an NGC, and permethrin was categorized as an NT; both predictions were supported by recently published papers. Our study has two important features: (i) as the first study to employ gene networks without using conventional quantitative structure-activity relationships (QSARs) as input data for SVMs to analyze toxicogenomics data in an hESC validation system, it uses additional information of gene-to-gene interactions to significantly increase prediction accuracies for noisy gene expression data; and (ii) using only undifferentiated hESCs, our study has considerable potential to predict late-onset chemical toxicities, including abnormalities that occur during embryonic development. PMID:27207879

  19. Prediction of developmental chemical toxicity based on gene networks of human embryonic stem cells

    PubMed Central

    Yamane, Junko; Aburatani, Sachiyo; Imanishi, Satoshi; Akanuma, Hiromi; Nagano, Reiko; Kato, Tsuyoshi; Sone, Hideko; Ohsako, Seiichiroh; Fujibuchi, Wataru

    2016-01-01

    Predictive toxicology using stem cells or their derived tissues has gained increasing importance in biomedical and pharmaceutical research. Here, we show that toxicity category prediction by support vector machines (SVMs), which uses qRT-PCR data from 20 categorized chemicals based on a human embryonic stem cell (hESC) system, is improved by the adoption of gene networks, in which network edge weights are added as feature vectors when noisy qRT-PCR data fail to make accurate predictions. The accuracies of our system were 97.5–100% for three toxicity categories: neurotoxins (NTs), genotoxic carcinogens (GCs) and non-genotoxic carcinogens (NGCs). For two uncategorized chemicals, bisphenol-A and permethrin, our system yielded reasonable results: bisphenol-A was categorized as an NGC, and permethrin was categorized as an NT; both predictions were supported by recently published papers. Our study has two important features: (i) as the first study to employ gene networks without using conventional quantitative structure-activity relationships (QSARs) as input data for SVMs to analyze toxicogenomics data in an hESC validation system, it uses additional information of gene-to-gene interactions to significantly increase prediction accuracies for noisy gene expression data; and (ii) using only undifferentiated hESCs, our study has considerable potential to predict late-onset chemical toxicities, including abnormalities that occur during embryonic development. PMID:27207879

  20. Interspecies quantitative structure-activity relationships (QSARs) for eco-toxicity screening of chemicals: the role of physicochemical properties.

    PubMed

    Furuhama, A; Hasunuma, K; Aoki, Y

    2015-01-01

    In addition to molecular structure profiles, descriptors based on physicochemical properties are useful for explaining the eco-toxicities of chemicals. In a previous study we reported that a criterion based on the difference between the partition coefficient (log POW) and distribution coefficient (log D) values of chemicals enabled us to identify aromatic amines and phenols for which interspecies relationships with strong correlations could be developed for fish-daphnid and algal-daphnid toxicities. The chemicals that met the log D-based criterion were expected to have similar toxicity mechanisms (related to membrane penetration). Here, we investigated the applicability of log D-based criteria to the eco-toxicity of other kinds of chemicals, including aliphatic compounds. At pH 10, use of a log POW - log D > 0 criterion and omission of outliers resulted in the selection of more than 100 chemicals whose acute fish toxicities or algal growth inhibition toxicities were almost equal to their acute daphnid toxicities. The advantage of log D-based criteria is that they allow for simple, rapid screening and prioritizing of chemicals. However, inorganic molecules and chemicals containing certain structural elements cannot be evaluated, because calculated log D values are unavailable.

  1. In silico prediction of toxicity of non-congeneric industrial chemicals using ensemble learning based modeling approaches

    SciTech Connect

    Singh, Kunwar P. Gupta, Shikha

    2014-03-15

    Ensemble learning approach based decision treeboost (DTB) and decision tree forest (DTF) models are introduced in order to establish quantitative structure–toxicity relationship (QSTR) for the prediction of toxicity of 1450 diverse chemicals. Eight non-quantum mechanical molecular descriptors were derived. Structural diversity of the chemicals was evaluated using Tanimoto similarity index. Stochastic gradient boosting and bagging algorithms supplemented DTB and DTF models were constructed for classification and function optimization problems using the toxicity end-point in T. pyriformis. Special attention was drawn to prediction ability and robustness of the models, investigated both in external and 10-fold cross validation processes. In complete data, optimal DTB and DTF models rendered accuracies of 98.90%, 98.83% in two-category and 98.14%, 98.14% in four-category toxicity classifications. Both the models further yielded classification accuracies of 100% in external toxicity data of T. pyriformis. The constructed regression models (DTB and DTF) using five descriptors yielded correlation coefficients (R{sup 2}) of 0.945, 0.944 between the measured and predicted toxicities with mean squared errors (MSEs) of 0.059, and 0.064 in complete T. pyriformis data. The T. pyriformis regression models (DTB and DTF) applied to the external toxicity data sets yielded R{sup 2} and MSE values of 0.637, 0.655; 0.534, 0.507 (marine bacteria) and 0.741, 0.691; 0.155, 0.173 (algae). The results suggest for wide applicability of the inter-species models in predicting toxicity of new chemicals for regulatory purposes. These approaches provide useful strategy and robust tools in the screening of ecotoxicological risk or environmental hazard potential of chemicals. - Graphical abstract: Importance of input variables in DTB and DTF classification models for (a) two-category, and (b) four-category toxicity intervals in T. pyriformis data. Generalization and predictive abilities of the

  2. Apparatus for rapid measurement of aerosol bulk chemical composition

    DOEpatents

    Lee, Yin-Nan E.; Weber, Rodney J.

    2003-01-01

    An apparatus and method for continuous on-line measurement of chemical composition of aerosol particles with a fast time resolution are provided. The apparatus includes a modified particle size magnifier for producing activated aerosol particles and a collection device which collects the activated aerosol particles into a liquid stream for quantitative analysis by analytical methods. The method provided for on-line measurement of chemical composition of aerosol particles includes exposing aerosol carrying sample air to hot saturated steam thereby forming activated aerosol particles; collecting the activated aerosol particles by a collection device for delivery as a jet stream onto an impaction surface; flushing off the activated aerosol particles from the impaction surface into a liquid stream for delivery of the collected liquid stream to an analytical instrument for quantitative measurement.

  3. Apparatus for rapid measurement of aerosol bulk chemical composition

    DOEpatents

    Lee, Yin-Nan E.; Weber, Rodney J.; Orsini, Douglas

    2006-04-18

    An apparatus for continuous on-line measurement of chemical composition of aerosol particles with a fast time resolution is provided. The apparatus includes an enhanced particle size magnifier for producing activated aerosol particles and an enhanced collection device which collects the activated aerosol particles into a liquid stream for quantitative analysis by analytical means. Methods for on-line measurement of chemical composition of aerosol particles are also provided, the method including exposing aerosol carrying sample air to hot saturated steam thereby forming activated aerosol particles; collecting the activated aerosol particles by a collection device for delivery as a jet stream onto an impaction surface; and flushing off the activated aerosol particles from the impaction surface into a liquid stream for delivery of the collected liquid stream to an analytical instrument for quantitative measurement.

  4. Chemical Composition of Defatted Cottonseed and Soy Meal Products

    PubMed Central

    He, Zhongqi; Zhang, Hailin; Olk, Dan C.

    2015-01-01

    Chemical composition is critical information for product quality and exploration of new use. Hence defatted cottonseed meals from both glanded (with gossypol) and glandless (without gossypol) cotton seeds were separated into water soluble and insoluble fractions, or water soluble, alkali soluble as well as total protein isolates. The contents of gossypol, total protein and amino acids, fiber and carbohydrates, and selected macro and trace elements in these products were determined and compared with each other and with those of soy meal products. Data reported in this work improved our understanding on the chemical composition of different cottonseed meal products that is helpful for more economical utilization of these products. These data would also provide a basic reference for product standards and quality control when the production of the cottonseed meal products comes to pilot and industrial scales. PMID:26079931

  5. Identification of Chemical Vascular Disruptors During Development Using An Integrative Predictive Toxicity Model and Zebrafish and in Vitro Functional Angiogenesis Assays.

    EPA Science Inventory

    Identification of chemical vascular disruptors during development using an integrative predictive toxicity model and zebrafish and in vitro functional angiogenesis assays Chemically-induced vascular toxicity during embryonic development can result in a wide range of adverse pre...

  6. Chemical composition of the flower oil of Cinnamomum zeylanicum blume.

    PubMed

    Jayaprakasha, G K; Jagan Mohan Rao, L; Sakariah, K K

    2000-09-01

    The steam-distilled oil of cinnamon (Cinnamomum zeylanicum) flowers was analyzed by GC and GC-MS. It consists of 23% hydrocarbons and 74% oxygenated compounds. A total of 26 compounds constituting approximately 97% of the oil were characterized. (E)-Cinnamyl acetate (41.98%), trans-alpha-bergamotene (7.97%), and caryophyllene oxide (7.2%) are found to be major compounds. This is the first report on the chemical composition of the flower oil of Cinnamomum zeylanicum.

  7. Chemical composition of the essential oil from Carramboa littlei (Asteraceae).

    PubMed

    de Rojas, Yndra Cordero; Rojas, Luis B; Usubillaga, Alfredo

    2011-01-01

    The essential oil from the leaves of Carramboa littlei Aristeg. was isolated by hydrodistillation yielding 0.09%, w/v. The chemical composition was determined by GC-FID and GC-MS. Sixteen components were identified by comparison of their mass spectra with Wiley and NIST library data. The major constituents of the oil were germacrene-D (50.0%), bicyclogermacrene (4.8%) and ent-kaur-16-en-19-al (21.8%).

  8. A systematic study of mitochondrial toxicity of environmental chemicals using quantitative high throughput screening

    PubMed Central

    Attene-Ramos, Matias S.; Huang, Ruili; Sakamuru, Srilatha; Witt, Kristine L.; Beeson, Gyda C.; Shou, Louie; Schnellmann, Rick G.; Beeson, Craig C.; Tice, Raymond R.; Austin, Christopher P.; Xia, Menghang

    2014-01-01

    A goal of the Tox21 program is to transit toxicity testing from traditional in vivo models to in vitro assays that assess how chemicals affect cellular responses and toxicity pathways. A critical contribution of the NIH Chemical Genomics center (NCGC) to the Tox21 program is the implementation of a quantitative high throughput screening (qHTS) approach, using cell- and biochemical-based assays to generate toxicological profiles for thousands of environmental compounds. Here, we evaluated the effect of chemical compounds on mitochondrial membrane potential in HepG2 cells by screening a library of 1,408 compounds provided by the National Toxicology Program (NTP) in a qHTS platform. Compounds were screened over 14 concentrations, and results showed that 91 and 88 compounds disrupted mitochondrial membrane potential after treatment for one or five h, respectively. Seventy-six compounds active at both time points were clustered by structural similarity, producing 11 clusters and 23 singletons. Thirty-eight compounds covering most of the active chemical space were more extensively evaluated. Thirty-six of the 38 compounds were confirmed to disrupt mitochondrial membrane potential using a fluorescence plate reader and 35 were confirmed using a high content imaging approach. Among the 38 compounds, 4 and 6 induced LDH release, a measure of cytotoxicity, at 1 or 5 h, respectively. Compounds were further assessed for mechanism of action (MOA) by measuring changes in oxygen consumption rate, which enabled identification of 20 compounds as uncouplers. This comprehensive approach allows for evaluation of thousands of environmental chemicals for mitochondrial toxicity and identification of possible MOAs. PMID:23895456

  9. International Federation of Gynecology and Obstetrics opinion on reproductive health impacts of exposure to toxic environmental chemicals.

    PubMed

    Di Renzo, Gian Carlo; Conry, Jeanne A; Blake, Jennifer; DeFrancesco, Mark S; DeNicola, Nathaniel; Martin, James N; McCue, Kelly A; Richmond, David; Shah, Abid; Sutton, Patrice; Woodruff, Tracey J; van der Poel, Sheryl Ziemin; Giudice, Linda C

    2015-12-01

    Exposure to toxic environmental chemicals during pregnancy and breastfeeding is ubiquitous and is a threat to healthy human reproduction. There are tens of thousands of chemicals in global commerce, and even small exposures to toxic chemicals during pregnancy can trigger adverse health consequences. Exposure to toxic environmental chemicals and related health outcomes are inequitably distributed within and between countries; universally, the consequences of exposure are disproportionately borne by people with low incomes. Discrimination, other social factors, economic factors, and occupation impact risk of exposure and harm. Documented links between prenatal exposure to environmental chemicals and adverse health outcomes span the life course and include impacts on fertility and pregnancy, neurodevelopment, and cancer. The global health and economic burden related to toxic environmental chemicals is in excess of millions of deaths and billions of dollars every year. On the basis of accumulating robust evidence of exposures and adverse health impacts related to toxic environmental chemicals, the International Federation of Gynecology and Obstetrics (FIGO) joins other leading reproductive health professional societies in calling for timely action to prevent harm. FIGO recommends that reproductive and other health professionals advocate for policies to prevent exposure to toxic environmental chemicals, work to ensure a healthy food system for all, make environmental health part of health care, and champion environmental justice. PMID:26433469

  10. International Federation of Gynecology and Obstetrics opinion on reproductive health impacts of exposure to toxic environmental chemicals.

    PubMed

    Di Renzo, Gian Carlo; Conry, Jeanne A; Blake, Jennifer; DeFrancesco, Mark S; DeNicola, Nathaniel; Martin, James N; McCue, Kelly A; Richmond, David; Shah, Abid; Sutton, Patrice; Woodruff, Tracey J; van der Poel, Sheryl Ziemin; Giudice, Linda C

    2015-12-01

    Exposure to toxic environmental chemicals during pregnancy and breastfeeding is ubiquitous and is a threat to healthy human reproduction. There are tens of thousands of chemicals in global commerce, and even small exposures to toxic chemicals during pregnancy can trigger adverse health consequences. Exposure to toxic environmental chemicals and related health outcomes are inequitably distributed within and between countries; universally, the consequences of exposure are disproportionately borne by people with low incomes. Discrimination, other social factors, economic factors, and occupation impact risk of exposure and harm. Documented links between prenatal exposure to environmental chemicals and adverse health outcomes span the life course and include impacts on fertility and pregnancy, neurodevelopment, and cancer. The global health and economic burden related to toxic environmental chemicals is in excess of millions of deaths and billions of dollars every year. On the basis of accumulating robust evidence of exposures and adverse health impacts related to toxic environmental chemicals, the International Federation of Gynecology and Obstetrics (FIGO) joins other leading reproductive health professional societies in calling for timely action to prevent harm. FIGO recommends that reproductive and other health professionals advocate for policies to prevent exposure to toxic environmental chemicals, work to ensure a healthy food system for all, make environmental health part of health care, and champion environmental justice.

  11. A high-throughput method for assessing chemical toxicity using a Caenorhabditis elegans reproduction assay

    SciTech Connect

    Boyd, Windy A.; McBride, Sandra J.; Rice, Julie R.; Snyder, Daniel W.; Freedman, Jonathan H.

    2010-06-01

    The National Research Council has outlined the need for non-mammalian toxicological models to test the potential health effects of a large number of chemicals while also reducing the use of traditional animal models. The nematode Caenorhabditis elegans is an attractive alternative model because of its well-characterized and evolutionarily conserved biology, low cost, and ability to be used in high-throughput screening. A high-throughput method is described for quantifying the reproductive capacity of C. elegans exposed to chemicals for 48 h from the last larval stage (L4) to adulthood using a COPAS Biosort. Initially, the effects of exposure conditions that could influence reproduction were defined. Concentrations of DMSO vehicle {<=} 1% did not affect reproduction. Previous studies indicated that C. elegans may be influenced by exposure to low pH conditions. At pHs greater than 4.5, C. elegans reproduction was not affected; however below this pH there was a significant decrease in the number of offspring. Cadmium chloride was chosen as a model toxicant to verify that automated measurements were comparable to those of traditional observational studies. EC{sub 50} values for cadmium for automated measurements (176-192 {mu}M) were comparable to those previously reported for a 72-h exposure using manual counting (151 {mu}M). The toxicity of seven test toxicants on C. elegans reproduction was highly correlative with rodent lethality suggesting that this assay may be useful in predicting the potential toxicity of chemicals in other organisms.

  12. Quantile regression model for a diverse set of chemicals: application to acute toxicity for green algae.

    PubMed

    Villain, Jonathan; Lozano, Sylvain; Halm-Lemeille, Marie-Pierre; Durrieu, Gilles; Bureau, Ronan

    2014-12-01

    The potential of quantile regression (QR) and quantile support vector machine regression (QSVMR) was analyzed for the definitions of quantitative structure-activity relationship (QSAR) models associated with a diverse set of chemicals toward a particular endpoint. This study focused on a specific sensitive endpoint (acute toxicity to algae) for which even a narcosis QSAR model is not actually clear. An initial dataset including more than 401 ecotoxicological data for one species of algae (Selenastrum capricornutum) was defined. This set corresponds to a large sample of chemicals ranging from classical organic chemicals to pesticides. From this original data set, the selection of the different subsets was made in terms of the notion of toxic ratio (TR), a parameter based on the ratio between predicted and experimental values. The robustness of QR and QSVMR to outliers was clearly observed, thus demonstrating that this approach represents a major interest for QSAR associated with a diverse set of chemicals. We focused particularly on descriptors related to molecular surface properties.

  13. Kinetic characterization and in vitro toxicity evaluation of a luciferase less susceptible to HPV chemical inhibition.

    PubMed

    Kim-Choi, Eileen; Danilo, Christiane; Kelly, Jeffrey; Carroll, Ronnie; Shonnard, David; Rybina, Irina

    2006-12-01

    Enzyme-based in vitro toxicity assays are often susceptible to inhibition by test compounds. A mutant luciferase selected to be less susceptible to inhibition by chloroform (CNBLuc03-06) and other high production volume (HPV) chemicals, consisting of three point mutations was created and characterized. The mutant luciferase was less inhibited by chloroform, other HPV chemicals and common surfactant release reagents (Triton-X and SDS) compared to the wild-type. Inhibition was shown to be competitive. CNBLuc03-06 was a factor of 1.5-3.2 more active than wild type and exhibited a much higher affinity for ATP. CNBLuc03-06 was more thermostable than wild-type and also more active at pH values higher than 10. Both luciferases exhibited a significant tradeoff between activation and susceptibility to chemical inhibition in the presences of the reducing agent DTT. Inhibition to HPV chemicals was eliminated using an "optimum" formulation of DTT and co-solvent ethanol. The performance of CNBLuc03-06 in cell-based in vitro toxicity assays was shown to be superior to the current commercial formulation.

  14. Acute lethal toxicity of some reference chemicals to freshwater fishes of Scandinavia

    SciTech Connect

    Oikari, A.O.J.

    1987-07-01

    Relevance of the choice of a test organism intended to be representative for a given environment seems to be under continual debate in aquatic ecotoxicology. For instance, it is commonly argue that acute toxicity tests with rainbow trout, the species most often recommended as a standard cold water teleost, were not representative for Nordic countries because the species is an alien in local faunas. A comparative study with several freshwater species was therefore initiated to clarify the validity of this assumption. As a first approximation, standard LC 50 assays were conducted. The species used were chosen only on the basis of their local availability, i.e, they randomly represented the fish fauna of Nordic inland waters. Furthermore, inter-species variation of toxicity response was compared with certain other, quantitatively more important, intra-species sources of variability affecting the toxicity of chemicals. Use of reference toxicants has been recommended as a means of standardizing bioassays. Compounds, characteristic of effluents from the pulp and paper industry, were selected for the present study. The toxicity of organic acids such a phenols and resin acids, as well as that of pupmill effluents, strongly depends on water pH. Because of the possibility that species differences could exist in this respect, effects of water acidity on toxicity of these types of substances to a randomly selected local species was investigated. Finally, as an example of the biological source of assay variability, the effect of yolk absorption was studied with a subsequent crisis period due to moderate starvation under laboratory conditions.

  15. In vitro and in vivo toxicity of rinsed and aged nanocellulose-polypyrrole composites.

    PubMed

    Ferraz, Natalia; Strømme, Maria; Fellström, Bengt; Pradhan, Sulena; Nyholm, Leif; Mihranyan, Albert

    2012-08-01

    Novel composites of nanocellulose and the conducting polymer polypyrrole (PPy) are herein suggested as potential candidates for active ion-extraction membranes in electrochemically controlled hemodialysis. This study has defined processing parameters to obtain a biocompatible nanocellulose-PPy composite, and for the first time, the effect of the composite aging on cell viability has been studied. The influence of rinsing and extraction process steps, as well as aging under different conditions (i.e. in air, at -20°C and in argon), on the electroactivity and cytotoxicity of a PPy-nanocellulose composite has been investigated. The biocompatibility evaluation was based on indirect toxicity assays with fibroblasts and monocyte cell lines and an acute toxicity test in mice, while the electroactivity was evaluated by cyclic voltammetry experiments. The as-prepared composite did not induce any cytotoxic response in vitro or in vivo. Extensive rinsing and 48 h incubation in biological buffer previous to the preparation of the culture medium extracts were, however, necessary to obtain a noncytotoxic composite. The as-prepared composite was also found to exhibit acceptable electrochemical performance, which was retained upon 4 weeks storage in argon atmosphere. It was shown that aging of the composite had a negative effect on biocompatibility, regardless of the storage condition. Thus, to allow for longtime storage of electroactive nanocellulose-PPy hemodialysis membranes, the degradation of PPy upon storage must be controlled. The present results show that the biocompatibility of PPy composites depends on the rinsing and pretreatment of the composite material as well as the aging of the material.

  16. Measurements of aerosol chemical composition in boreal forest summer conditions

    NASA Astrophysics Data System (ADS)

    ńijälä, M.; Junninen, H.; Ehn, M.; Petäjä, T.; Vogel, A.; Hoffmann, T.; Corrigan, A.; Russell, L.; Makkonen, U.; Virkkula, A.; Mäntykenttä, J.; Kulmala, M.; Worsnop, D.

    2012-04-01

    Boreal forests are an important biome, covering vast areas of the northern hemisphere and affecting the global climate change via various feedbacks [1]. Despite having relatively few anthropogenic primary aerosol sources, they always contain a non-negligible aerosol population [2]. This study describes aerosol chemical composition measurements using Aerodyne Aerosol Mass Spectrometer (C-ToF AMS, [3]), carried out at a boreal forest area in Hyytiälä, Southern Finland. The site, Helsinki University SMEAR II measurement station [4], is situated at a homogeneous Scots pine (Pinus sylvestris) forest stand. In addition to the station's permanent aerosol, gas phase and meteorological instruments, during the HUMPPA (Hyytiälä United Measurements of Photochemistry and Particles in Air) campaign in July 2010, a very comprehensive set of atmospheric chemistry measurement instrumentation was provided by the Max Planck Institute for chemistry, Johannes Gutenberg-University, University of California and the Finnish Meteorological institute. In this study aerosol chemical composition measurements from the campaign are presented. The dominant aerosol chemical species during the campaign were the organics, although periods with elevated amounts of particulate sulfates were also seen. The overall AMS measured particle mass concentrations varied from near zero to 27 μg/m observed during a forest fire smoke episode. The AMS measured aerosol mass loadings were found to agree well with DMPS derived mass concentrations (r2=0.998). The AMS data was also compared with three other aerosol instruments. The Marga instrument [5] was used to provide a quantitative semi-online measurement of inorganic chemical compounds in particle phase. Fourier Transform Infrared Spectroscopy (FTIR) analysis was performed on daily filter samples, enabling the identification and quantification of organic aerosol subspecies. Finally an Atmospheric Pressure Chemical Ionization Ion Trap Mass Spectrometer (APCI

  17. Chemical composition studies of flint with different origins

    NASA Astrophysics Data System (ADS)

    Zarina, Liga; Seglins, Valdis; Kostjukovs, Juris; Burlakovs, Juris

    2015-04-01

    Flint is a widely used material in the Stone Age because of its physical characteristics, which makes the material suitable for obtaining tools with sharp working edges. Chert, flint, chalcedony, agate and jasper in composition and several other physical characteristics are very similar. Therefore in archaeology most often they are determined simplified and are not distinguished, but described as flint or chert, denoting only the material in a general sense. However, in-depth studies it is necessary accurately identify the rock type and, in addition, to determine the origin of the flint and the conditions of the formation for the various archaeological research needs. As a typical example can be noted the localization problems in determining whether flint is local, or have emerged in the region through the exchange or by transportation. Flint consists mainly from quartz and mostly it has cryptocrystalline or amorphous structure. In nature it occurs as nodules and interbedded inclusions in sedimentary deposits as a result of digenesis processes when calcium carbonate is replaced with silicia. Bedded chert primarily is accumulations originated from excess alkalinity in the sediments. Flint can also be formed in the crystallization processes of the chemically unstable amorphous silicia. In this context, it should be noted that flint is naturally heterogeneous and very varied material by the physical properties and therefore problematic in many contemporary studies. In the study different origin flint samples from England, Denmark and Latvia were compared after their chemical composition. Flint nodules from Northern Europe chalk cliffs formed as inclusions in interbedded deposits or results of the digenesis and samples of chalcedony saturated dolomite from Latvia formed in hydrothermal processes were analysed using XRD and XRF methods. The obtained data were statistically analysed, identifying major, minor and trace elements and subsequently assessing the chemical

  18. Toxic fables: the advertising and marketing of agricultural chemicals in the great plains, 1945-1985.

    PubMed

    Vail, David D

    2012-12-01

    This paper examines how pesticides and their technologies were sold to farmers and pilots throughout the midtwentieth century. It principally considers how marketing rhetoric and advertisement strategies used by chemical companies and aerial spraying firms influenced the practices and perspectives of farm producers in the Great Plains. In order to convince landowners and agricultural leaders to buy their pesticides, chemical companies generated advertisements that championed local crop health, mixture accuracy, livestock safety and a chemical-farming 'way of life' that kept fields healthy and productive. Combining notions of safety, accuracy and professionalism with pest eradication messages reinforced the standards that landowners, pilots and agriculturalists would hold regarding toxicity and risk when spraying their fields. As the politics of health changed in the aftermath of Rachel Carson's Silent Spring, these companies and aerial spraying outfits responded by keeping to a vision of agricultural health that required poisons for protection through technological accuracy.

  19. Chemical composition of dissolved organic matter draining permafrost soils

    NASA Astrophysics Data System (ADS)

    Ward, Collin P.; Cory, Rose M.

    2015-10-01

    Northern circumpolar permafrost soils contain roughly twice the amount of carbon stored in the atmosphere today, but the majority of this soil organic carbon is perennially frozen. Climate warming in the arctic is thawing permafrost soils and mobilizing previously frozen dissolved organic matter (DOM) from deeper soil layers to nearby surface waters. Previous studies have reported that ancient DOM draining deeper layers of permafrost soils was more susceptible to degradation by aquatic bacteria compared to modern DOM draining the shallow active layer of permafrost soils, and have suggested that DOM chemical composition may be an important control for the lability of DOM to bacterial degradation. However, the compositional features that distinguish DOM drained from different depths in permafrost soils are poorly characterized. Thus, the objective of this study was to characterize the chemical composition of DOM drained from different depths in permafrost soils, and relate these compositional differences to its susceptibility to biological degradation. DOM was leached from the shallow organic mat and the deeper permafrost layer of soils within the Imnavait Creek watershed on the North Slope of Alaska. DOM draining both soil layers was characterized in triplicate by coupling ultra-high resolution mass spectrometry, 13C solid-state NMR, and optical spectroscopy methods with multi-variate statistical analyses. Reproducibility of replicate mass spectra was high, and compositional differences resulting from interfering species or isolation effects were significantly smaller than differences between DOM drained from each soil layer. All analyses indicated that DOM leached from the shallower organic mat contained higher molecular weight, more oxidized, and more unsaturated aromatic species compared to DOM leached from the deeper permafrost layer. Bacterial production rates and bacterial efficiencies were significantly higher for permafrost compared to organic mat DOM

  20. Chemicals in the environment and developmental toxicity to children: a public health and policy perspective.

    PubMed

    Goldman, L R; Koduru, S

    2000-06-01

    There are numerous pesticides and toxic chemicals in the environment that have yet to be evaluated for potential to cause developmental neurotoxicity. Recent legislation and testing initiatives provide an impetus to generating more information about potential hazards to children. In the United States, the 1996 Food Quality Protection Act (FQPA) required the U.S. Environmental Protection Agency (U.S. EPA) to make a finding that a pesticide food use is safe for children. In addition, the law requires U.S. EPA to incorporate an additional 10-fold factor in risk assessments for pesticide residue tolerances to take into account the special sensitivities of infants and children as well as incomplete data with respect to toxicity and exposures. The potential of chemicals in food and drinking water to cause endocrine disruption will also be examined via the Endocrine Disruptor Screening and Testing Program required by the FQPA and the 1996 Safe Drinking Water Act. In addition, a new voluntary chemical information program will provide screening-level information for the some 2,800 high-volume chemicals in commerce in the United States. These initiatives will need to be accompanied by research focused on developmental toxicity for children, including developmental disabilities. Developmental disabilities exact a large toll on children's health in the United States. Three major developmental disabilities--autism, cerebral palsy, and severe mental retardation--each affect substantial numbers of children. We know very little about the etiology of these conditions. A number of priority areas for research are suggested, including a large environmental prospective study of developmental neurotoxicity. PMID:10852843

  1. Chemical Response of the Toxic Dinoflagellate Karenia mikimotoi Against Grazing by Three Species of Zooplankton.

    PubMed

    Dang, Lin-Xi; Li, Yue; Liu, Fei; Zhang, Yong; Yang, Wei-Dong; Li, Hong-Ye; Liu, Jie-Sheng

    2015-01-01

    We investigated the toxicity of Karenia mikimotoi toward three model grazers, the cladoceran Moina mongolica, the copepod Pseudodiaptomus annandalei, and the crustacean Artemia salina, and explored its chemical response upon zooplankton grazing. An induction experiment, where K. mikimotoi was exposed to grazers or waterborne cues from the mixed cultures revealed that K. mikimotoi might be toxic or nutritionally inadequate toward the three grazers. In general, direct exposure to the three grazers induced the production of hemolytic toxins and the synthesis of eicosapentaenoic acid (EPA). Both EPA and the hemolytic toxins from K. mikimotoi decreased the survival rate of the three grazers. In addition, the survival rates of M. mongolica, P. annandalei, and A. salina in the presence of induced K. mikimotoi that had previously been exposed to a certain grazer were lower than their counterparts caused by fresh K. mikimotoi, suggesting that exposure to some grazers might increase the toxicity of K. mikimotoi. The chemical response and associated increased resistance to further grazing suggested that K. mikimotoi could produce deterrents to protect against grazing by zooplankton and that the substances responsible might be hemolytic toxins and EPA. PMID:25523905

  2. Physico-chemical properties and toxicity of alkylated polycyclic aromatic hydrocarbons.

    PubMed

    Kang, Hyun-Joong; Lee, So-Young; Kwon, Jung-Hwan

    2016-07-15

    Crude oil and refined petroleum products contain many polycyclic and heterocyclic aromatic hydrocarbons, in particular, alkylated PAHs. Although alkylated PAHs are found in significantly higher quantities than their corresponding unsubstituted PAHs, the most studies on the physico-chemical properties and toxicities of these compounds have been conducted on unsubstituted PAHs. In this study, we measured crucial physico-chemical properties (i.e., water solubility, partition coefficients between polydimethylsiloxane and water (KPDMSw), and partition coefficient between liposomes and water (Klipw)) of selected alkylated PAHs, and evaluated their toxicity using the luminescence inhibition of Aliivibrio fischeri and growth inhibition of Raphidocelis subcapitata. In general, the logarithms of these properties for alkylated PAHs showed good linear correlations with log Kow, as did those for unsubstituted PAHs. Changes in molecular symmetry on the introduction of alkyl groups on aromatic ring structure significantly altered water solubility. The inhibition of bacterial luminescence and algal growth by alkylated PAHs can be explained well by the baseline toxicity hypothesis, and good linear relationships between log Kow or log Klipw and log (1/EC50) were found.

  3. Development of a plant bioassay to assess toxicity of chemical stressors to emergent macrophytes

    SciTech Connect

    Powell, R.L.; Kimerle, R.A.; Moser, E.M.

    1996-09-01

    A static renewal bioassay has been proposed to evaluate the effects of chemical stressors on the growth of emergent macrophytes. Bioassay methods were developed using Oryza sativa L. (domestic rice) as the test species and boron as the test compound. After culturing O. sativa in a natural sediment for 2 weeks, the plants were continuously exposed to various concentrations of boron dissolved in the dilution water. At the end of the exposure period the plants were evaluated. Endpoints included visual observations, dry weight, residue, and chlorophyll concentration in the leaf tissue. Dose-response relationships were established for each endpoint; however, dry weight appears to be the least sensitive endpoint. Exposure duration also significantly influenced toxic values. The bioassay procedure was then used to screen several other emergent macrophytes for toxicity to boron. Visual observations and residue indicated treatment differences for each of these species; however, dry weight and chlorophyll concentration did not confirm the differences. Oryza sativa plants exposed to water naturally contaminated with boron accumulated similar concentrations of boron in their leaf tissue as plants exposed to laboratory-prepared solutions of boron. Based on the data presented here, this bioassay appears to be useful in evaluating the potential toxicity of chemical stressors to emergent macrophytes.

  4. Land treatment of PAH-contaminated soil: Performance measured by chemical and toxicity assays

    SciTech Connect

    Sayles, G.D.; Acheson, C.M.; Kupferle, M.J.; Shan, Y.; Zhou, Q.; Meier, J.R.; Chang, L.; Brenner, R.C.

    1999-12-01

    The performance of a soil remediation process can be determined by measuring the reduction in target soil contaminant concentrations and by assessing the treatment's ability to lower soil toxicity. Land treatment of polycyclic aromatic hydrocarbon (PAH)-contaminated soil from a former wood-treating site was simulated at pilot scale in temperature-controlled sol pans. Nineteen two- through six-ring PAHs were monitored with time (initial total PAHs = 2,800 mg/kg). Twenty-five weeks of treatment yielded a final total PAH level of 1,160 mg/kg. Statistically significant decreases in concentrations were seen in total, two-, three-, and four-ring PAHs. Carcinogenic and five- and six-ring PAHs showed no significant change in concentration. Land treatment resulted in significant toxicity reduction based on root elongation, Allium chromosomal aberration, and solid-phase Microtox bioassays. Acute toxicity, as measured by the earthworm survival assay, was significantly reduced and completely removed. The Ames spiral plate mutagenicity assay revealed that the untreated soil was slightly mutagenic and that treatment may have reduced mutagenicity. The variety of results generated from the chemical and toxicity assays emphasize the need for conducting a battery of such tests to fully understand soil remediation processes.

  5. Guidance on health effects of toxic chemicals. Safety Analysis Report Update Program

    SciTech Connect

    Foust, C.B.; Griffin, G.D.; Munro, N.B.; Socolof, M.L.

    1994-02-01

    Martin Marietta Energy Systems, Inc. (MMES), and Martin Marietta Utility Services, Inc. (MMUS), are engaged in phased programs to update the safety documentation for the existing US Department of Energy (DOE)-owned facilities. The safety analysis of potential toxic hazards requires a methodology for evaluating human health effects of predicted toxic exposures. This report provides a consistent set of health effects and documents toxicity estimates corresponding to these health effects for some of the more important chemicals found within MMES and MMUS. The estimates are based on published toxicity information and apply to acute exposures for an ``average`` individual. The health effects (toxicological endpoints) used in this report are (1) the detection threshold; (2) the no-observed adverse effect level; (3) the onset of irritation/reversible effects; (4) the onset of irreversible effects; and (5) a lethal exposure, defined to be the 50% lethal level. An irreversible effect is defined as a significant effect on a person`s quality of life, e.g., serious injury. Predicted consequences are evaluated on the basis of concentration and exposure time.

  6. Chemical contamination and toxicity of sediment from a coastal area receiving industrial effluents in Kuwait.

    PubMed

    Beg, M U; Al-Muzaini, S; Saeed, T; Jacob, P G; Beg, K R; Al-Bahloul, M; Al-Matrouk, K; Al-Obaid, T; Kurian, A

    2001-10-01

    The Shuaiba coastal area (12.5 x 1.5 km) was examined for contamination with total organic carbon, volatile organic matter, total petroleum hydrocarbons, polycyclic aromatic hydrocarbons, cadmium, chromium, copper, lead, nickel, vanadium, and zinc in sediment; their desorption by aqueous elution; and toxicity to aquatic biota. The pollutants were mainly accumulated in the upstream area facing Mina Al-Ahmadi refinery to Shuaiba harbour. Solid-phase Microtox assays showed severe toxicity, and the LC(50) was negatively correlated with most of the chemical parameters, suggesting that toxicity was the function of collective effects of the pollutants present in sediment. Sea water elutriation showed poor desorption of pollutants from sediment, and the elutriates were not found toxic to Microtox and brine shrimp larvae. Whole sediment suspension in sea water reduced the survival of fingerlings in fish bioassays. Action from Shuaiba Area Authority is required to reduce pollutant accumulation in identified depositional area on the Shuaiba coast by facilitating unrestricted water flow in the area and restricting pollutant discharge at source. PMID:11503065

  7. Impacts of chemical modification on the toxicity of diverse nanocellulose materials to developing zebrafish

    PubMed Central

    Harper, Bryan J.; Clendaniel, Alicea; Sinche, Federico; Way, Daniel; Hughes, Michael; Schardt, Jenna; Simonsen, John; Stefaniak, Aleksandr B.

    2016-01-01

    Cellulose is an abundant and renewable resource currently being investigated for utility in nanomaterial form for various promising applications ranging from medical and pharmaceutical uses to mechanical reinforcement and biofuels. The utility of nanocellulose and wide implementation ensures increasing exposure to humans and the environment as nanocellulose-based technologies advance. Here, we investigate how differences in aspect ratio and changes to surface chemistry, as well as synthesis methods, influence the biocompatibility of nanocellulose materials using the embryonic zebrafish. Investigations into the toxicity of neutral, cationic and anionic surface functionalities revealed that surface chemistry had a minimal influence on the overall toxicity of nanocellulose materials. Higher aspect ratio cellulose nanofibers produced by mechanical homogenization were, in some cases, more toxic than other cellulose-based nanofibers or nanocrystals produced by chemical synthesis methods. Using fluorescently labeled nanocellulose we were able to show that nanocellulose uptake did occur in embryonic zebrafish during development. We conclude that the benign nature of nanocellulose materials makes them an ideal platform to systematically investigate the inherent surface features driving nanomaterial toxicity in order to create safer design principles for engineered nanoparticles. PMID:27468180

  8. Comparing rapid-screening and standard toxicity assays to assess known chemical contamination at a hazardous waste site

    SciTech Connect

    Martino, L.; Swigert, J.; Roberts, C.

    1995-12-31

    The thrust to streamline the Superfund site investigation/remediation program makes it critical for site investigators to utilize rapid screening methodologies to facilitate decision-making. However, screening methodologies providing information upon which decision-making is based must not only be rapid but also scientifically valid. This presentation compares and contrasts two rapid screening toxicity assessments, the Daphnia magna IQ Toxicity Test {trademark} and Microtox{trademark}, to a battery of standard aquatic toxicity tests using Lemna, Rana, Pimephales, Selenastruni and Ceriodaphnia. Chemical analysis of test water samples provided evidence of potential toxicological risk associated with the test samples. The study site was J-Field, Aberdeen Proving Ground, Maryland, a federal facility listed on the National Priority List that used to test and/or dispose of high explosives and chemical warfare agents in open pits or fields. Surface water samples from 20 sites were collected and used in the toxicity assessments. Water samples also were analyzed for explosives, chemical surety degradation compounds, Target Analyte List (inorganics), Target Compound List (organics) and selected pesticides and PCBs. The Microtox{trademark} assay did not reveal any toxicity present in the samples analyzed. Correlation analyses showed only slight correlation between the Daphnia magna IQ{trademark} assay and the standard 48-hour toxicity test. No correlation existed between the Microtox{trademark} assay and the aquatic toxicity tests. Results are discussed in light of the expected risk of the chemicals known to be present and the outcome of the toxicity tests.

  9. A COMPARISON OF THE LETHAL AND SUBLETHAL TOXICITY OF ORGANIC CHEMICAL MIXTURES TO THE FATHEAD MINNOW (PIMEPHALES PROMELAS)

    EPA Science Inventory

    The joint toxic effects of known binary and multiple organic chemical mixtures to the fathead minnow (Pimephales promelas) were defined at both the 96-h 50% lethal effect concentration (LC50) and sublethal (32-d growth) response levels for toxicants with a narcosis I, narcosis II...

  10. ToxCast: Developing Predictive Signatures of Chemically Induced Toxicity (Developing Predictive Bioactivity Signatures from ToxCasts HTS Data)

    EPA Science Inventory

    ToxCast, the United States Environmental Protection Agency’s chemical prioritization research program, is developing methods for utilizing computational chemistry, bioactivity profiling and toxicogenomic data to predict potential for toxicity and prioritize limited testing resour...

  11. [Effect of processing on the chemical contents and hepatic and renal toxicity of rhubarb studied by canonical correlation analysis].

    PubMed

    Wang, Jia-Bo; Ma, Yong-Gang; Zhang, Ping; Jin, Cheng; Sun, Yu-Qi; Xiao, Xiao-He; Zhao, Yan-Ling; Zhou, Can-Ping

    2009-08-01

    In this article, canonical correlation analysis was used to explore the relationship between the toxicity-attenuating effect and the variation of chemical contents in rhubarb caused by processing. With quasi-acute toxicity test, the difference of hepatic and renal toxicity to mice with the processed materials of rhubarb was researched. The chemical contents of anthraquinones and tannins in rhubarb were measured by UV-vis spectrophotometry and high performance liquid chromatography. The results showed that there were toxic effects to liver and kidney in mice after repeated intragastric administration of rhubarb and its processed materials for 14 days at a dosage of 76 g x kg(-1). The toxic effect of processed materials was much lower than crude drug. With canonical correlation analysis, the sequence of the hepatic and renal toxicity of chemical contents in rhubarb were found as follows: total anthraquinone glycosides (AQGs) > tannins (Tns) > total anthraquinones (AQs); aloe-emodin (AE) > physcione (Ph) > rhein (Rn) > emodin (Ed) > chrysophanol (Ch) and AEG > PhG > ChG > EdG > RnG of glycosyl-anthraquinone. It could be concluded that processing would attenuate the toxicity of crude drug of rhubarb. The toxicity-attenuating effect might be correlated to the decline of the contents of both anthraquinone glycosides and tannins, especially the aloe-emodin glycoside and physcione glycoside. The results also suggested that the serum alanine aminotransferase (ALT) and creatine (CREA) would be useful to monitor the hepatic and renal toxicity of rhubarb.

  12. Anaerobic baffled reactor coupled with chemical precipitation for treatment and toxicity reduction of industrial wastewater.

    PubMed

    Laohaprapanona, Sawanya; Marquesa, Marcia; Hogland, William

    2014-01-01

    This study describes the reduction of soluble chemical oxygen demand (CODs) and the removal of dissolved organic carbon (DOC), formaldehyde (FA) and nitrogen from highly polluted wastewater generated during cleaning procedures in wood floor manufacturing using a laboratory-scale biological anaerobic baffled reactor followed by chemical precipitation using MgCI2 .6H20 + Na2HPO4. By increasing the hydraulic retention time from 2.5 to 3.7 and 5 days, the reduction rates of FA, DOC and CODs of nearly 100%, 90% and 83%, respectively, were achieved. When the Mg:N:P molar ratio in the chemical treatment was changed from 1:1:1 to 1.3:1:1.3 at pH 8, the NH4+ removal rate increased from 80% to 98%. Biologically and chemically treated wastewater had no toxic effects on Vibrio fischeri and Artemia salina whereas chemically treated wastewater inhibited germination of Lactuca sativa owing to a high salt content. Regardless of the high conductivity of the treated wastewater, combined biological and chemical treatment was found to be effective for the removal of the organic load and nitrogen, and to be simple to operate and to maintain. A combined process such as that investigated could be useful for on-site treatment of low volumes of highly polluted wastewater generated by the wood floor and wood furniture industries, for which there is no suitable on-site treatment option available today.

  13. IDENTIFICATION OF ENVIRONMENTAL CHEMICALS ASSOCIATED WITH THE DEVELOPMENT OF TOXICANT ASSOCIATED FATTY LIVER DISEASE IN RODENTS

    PubMed Central

    Al-Eryani, Laila; Wahlang, Banrida; Falkner, K.C.; Guardiola, J. J.; Clair, H.B.; Prough, R.A.; Cave, M.

    2014-01-01

    Background Toxicant associated fatty liver disease (TAFLD) is a recently identified form of non-alcoholic fatty liver disease (NAFLD) associated with exposure to industrial chemicals and environmental pollutants. Numerous studies have been conducted to test the association between industrial chemicals/ environmental pollutants and fatty liver disease both in vivo and in vitro. Objectives The objective of the paper is to report a list of chemicals associated with TAFLD. Methods Two federal databases of rodent toxicology studies– ToxRefDB (Environmental Protection Agency) and Chemical Effects in Biological Systems (CEBS, National Toxicology Program) were searched for liver endpoints. Combined, these two databases archive nearly 2000 rodent studies. TASH descriptors including fatty change, fatty necrosis, Oil red O positive staining, steatosis and lipid deposition were queried. Results Using these search terms, 123 chemicals associated with fatty liver were identified. Pesticides and solvents were the most frequently identified chemicals, while PCBs/dioxins were the most potent. About 44% of identified compounds were pesticides or their intermediates, and nearly 10% of pesticide registration studies in ToxRefDB were associated with fatty liver. Fungicides and herbicides were more frequently associated with fatty liver than insecticides. Conclusions More research on pesticides, solvents, metals and PCBs/dioxins in NAFLD/TAFLD is warranted due to their association with liver damage. PMID:25326588

  14. Removal of persistent bioaccumulative toxic chemicals from pulp and paper mill effluent streams

    SciTech Connect

    Holm, S.E.

    1995-12-31

    Several organizations have called for the reduction of PBTs or Persistent Bioaccumulative Toxics because of this class of chemicals potential environmental consequences when released into the environment. PBTs are persistent because of their resistance to biological contamination, because they bioaccumulate in the fatty tissue of organisms, and are toxic to aquatic species at relatively low levels. PBTs may be produced commercially such as for use as a pesticide or herbicide or inadvertently as byproducts, such as from diesel engines, incinerators, and during pulp bleaching using chlorine or chlorine derivatives. This paper will show how the pulp and paper industry has utilized the pollution prevention technique of process change to remove the levels of PBTs from its waste stream and how this process change relates to decreasing levels of specific PBTs in the environment. Chlorinated phenolic compounds and dioxin will be used as examples.

  15. Chemical Composition of Rainwater in Córdoba City, Argentina

    NASA Astrophysics Data System (ADS)

    López, M. L.; Asar, M. L.; Ceppi, S.; Bürgesser, R. E.; Avila, E.

    2013-05-01

    Sampling and chemical analysis of rainwater has proved to be a useful technique for studying its chemical composition and provides a greater understanding of local and regional dispersion of pollutants and their potential impacts to ecosystems through deposition processes. Samples of rainwater were collected during 2009-2012, in Córdoba city, Argentina. Two kind of sampling were performed: event-specific and sequential. The objective of the first of these was to determine the chemical concentration of the total rain, while the objective of the second one was to analyze the variability of the chemical concentration during an individual rain event. The total volume of each sample was divided in halves. One half was filtered through 0.45 μm membrane filter. After this, all the samples were reduced by evaporation to a final volume of 10 ml. The non-filtered samples were acidified and digested in accordance to the method 3050B of the Environmental Protection Agency (EPA) for acid digestion of sediments. Multi-elemental standard solutions in different concentrations were prepared by adequate dilutions. Gallium was added as an internal standard in all standard solutions and samples. Exactly 5 μL of these solutions were deposited on acrylic supports. When these droplets were dried, Synchrotron Radiation Total Reflection X-Ray Fluorescence technique was used for determining the chemical elements. Spectra were analyzed with the AXIL package for spectrum analysis. Due to the intrinsic characteristics of the total reflection technique, the background of the measurements is significantly reduced and there are no matrix effects, therefore quantification can be obtained from the linear correlation between fluorescence intensity and the concentration of the element of interest. The elements quantified were S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, and Pb. For all of them a calibration curve was performed in order to quantify their concentrations on the

  16. A bootstrap estimation scheme for chemical compositional data with nondetects

    USGS Publications Warehouse

    Palarea-Albaladejo, J; Martín-Fernández, J.A; Olea, Ricardo A.

    2014-01-01

    The bootstrap method is commonly used to estimate the distribution of estimators and their associated uncertainty when explicit analytic expressions are not available or are difficult to obtain. It has been widely applied in environmental and geochemical studies, where the data generated often represent parts of whole, typically chemical concentrations. This kind of constrained data is generically called compositional data, and they require specialised statistical methods to properly account for their particular covariance structure. On the other hand, it is not unusual in practice that those data contain labels denoting nondetects, that is, concentrations falling below detection limits. Nondetects impede the implementation of the bootstrap and represent an additional source of uncertainty that must be taken into account. In this work, a bootstrap scheme is devised that handles nondetects by adding an imputation step within the resampling process and conveniently propagates their associated uncertainly. In doing so, it considers the constrained relationships between chemical concentrations originated from their compositional nature. Bootstrap estimates using a range of imputation methods, including new stochastic proposals, are compared across scenarios of increasing difficulty. They are formulated to meet compositional principles following the log-ratio approach, and an adjustment is introduced in the multivariate case to deal with nonclosed samples. Results suggest that nondetect bootstrap based on model-based imputation is generally preferable. A robust approach based on isometric log-ratio transformations appears to be particularly suited in this context. Computer routines in the R statistical programming language are provided. 

  17. The physical and chemical composition of the lower mantle.

    PubMed

    Bovolo, C Isabella

    2005-12-15

    This article reviews some of the recent advances made within the field of mineral physics. In order to link the observed seismic and density structures of the lower mantle with a particular mineral composition, knowledge of the thermodynamic properties of the candidate materials is required. Determining which compositional model best matches the observed data is difficult because of the wide variety of possible mineral structures and compositions. State-of-the-art experimental and analytical techniques have pushed forward our knowledge of mineral physics, yet certain properties, such as the elastic properties of lower mantle minerals at high pressures and temperatures, are difficult to determine experimentally and remain elusive. Fortunately, computational techniques are now sufficiently advanced to enable the prediction of these properties in a self-consistent manner, but more results are required.A fundamental question is whether or not the upper and lower mantles are mixing. Traditional models that involve chemically separate upper and lower mantles cannot yet be ruled out despite recent conflicting seismological evidence showing that subducting slabs penetrate deep into the lower mantle and that chemically distinct layers are, therefore, unlikely.Recent seismic tomography studies giving three-dimensional models of the seismic wave velocities in the Earth also base their interpretations on the thermodynamic properties of minerals. These studies reveal heterogeneous velocity and density anomalies in the lower mantle, which are difficult to reconcile with mineral physics data.

  18. Reduced toxicity polyester resins and microvascular pre-preg tapes for advanced composites manufacturing

    NASA Astrophysics Data System (ADS)

    Poillucci, Richard

    Advanced composites manufacturing broadly encapsulates topics ranging from matrix chemistries to automated machines that lay-up fiber-reinforced materials. Environmental regulations are stimulating research to reduce matrix resin formulation toxicity. At present, composites fabricated with polyester resins expose workers to the risk of contact with and inhalation of styrene monomer, which is a potential carcinogen, neurotoxin, and respiratory irritant. The first primary goal of this thesis is to reduce the toxicity associated with polyester resins by: (1) identification of potential monomers to replace styrene, (2) determination of monomer solubility within the polyester, and (3) investigation of approaches to rapidly screen a large resin composition parameter space. Monomers are identified based on their ability to react with polyester and their toxicity as determined by the Globally Harmonized System (GHS) and a green screen method. Solubilities were determined by the Hoftyzer -- Van Krevelen method, Hansen solubility parameter database, and experimental mixing of monomers. A combinatorial microfluidic mixing device is designed and tested to obtain distinct resin compositions from two input chemistries. The push for safer materials is complemented by a thrust for multifunctional composites. The second primary goal of this thesis is to design and implement the manufacture of sacrificial fiber materials suitable for use in automated fiber placement of microvascaular multifunctional composites. Two key advancements are required to achieve this goal: (1) development of a roll-to-roll method to place sacrificial fibers onto carbon fiber pre-preg tape; and (2) demonstration of feasible manufacture of microvascular carbon fiber plates with automated fiber placement. An automated method for placing sacrificial fibers onto carbon fiber tapes is designed and a prototype implemented. Carbon fiber tows with manual placement of sacrificial fibers is implemented within an

  19. Determining chemical composition of materials through micro-CT images.

    PubMed

    Jussiani, Eduardo Inocente; Dos Reis, Paulo José; Appoloni, Carlos Roberto

    2016-10-01

    X-ray microtomography is a 3D non-destructive method which, through digital images, enables a view of the internal structure of samples. Recently, researchers have been extensively performing various methods in the attempt to determine the chemical composition of materials. This paper brings further insight into this matter and proposes a new experimental method for determining the internal chemical composition of samples. Using a set of standard samples, calibration curves can be created that allow to relate the average gray scale of a sample obtained through microtomographic images to the value of ρZeff(m). In this model, ρZeff(m) is the parameter that chemically characterizes a material. The exponent m is obtained by the average value obtained with standard samples, which were titanium dioxide (TiO2), calcium chloride (CaCl2), calcium hydroxide (Ca(OH)2), and calcium nitrate (Ca(NO3)2). For the samples scanning process, a Bruker SkyScan 1172 microCT was used for testing rocks, nylon, graphite, calcium carbonate (CaCO3) and aluminum samples. The experimental results achieved by this method were consistent with the theoretical values. PMID:27451140

  20. The aquatic toxicity and chemical forms of coke plant effluent cyanide -- Implications for discharge limits

    SciTech Connect

    Garibay, R.; Rupnow, M.; Godwin-Saad, E.; Hall, S.

    1995-12-31

    Cyanide is present in treated cokemaking process waters at concentrations as high as 8.0 mg/L. In assessing options for managing the discharge of a treated effluent, the development and implementation of discharge limits for cyanide became a critical issue. A study was initiated to evaluate possible alternatives to cyanide permit limits at the US Steel Gary Works Facility. The objectives of the study were to: (1) evaluation the forms of cyanide present in coke plant effluent; (2) determine whether these forms of cyanide are toxic to selected aquatic organisms; (3) compare the aquatic toxicity of various chemical forms of cyanide; (4) identify if the receiving water modifies cyanide bioavailability; and (5) confirm, with respect to water quality-based effluent limits, an appropriate analytical method for monitoring cyanide in a coke plant effluent. The results of aquatic toxicity tests and corresponding analytical data are presented. Toxicity tests were conducted with various pure chemical forms of cyanide as well as whole coke plant effluent (generated from a pilot-scale treatment system). Test species included the fathead minnow (Pimephales promelas), rainbow trout (Oncorhynchus mykiss), Ceriodaphnia dubia (C. dubia) and Daphnia magna (D. magna). Analytical measurements for cyanide included total, weak acid dissociable, diffusible cyanide and selected metal species of cyanide. The findings presented by the paper are relevant with respect to the application of cyanide water quality criteria for a coke plant effluent discharge, the translation of these water quality-based effluent limits to permit limits, and methods for compliance monitoring for cyanide.

  1. Toxic chemical release inventory reporting: Questions and answers (Qs&As)

    SciTech Connect

    Not Available

    1994-03-01

    On September 22, 1992, the Secretary of Energy directed the Department to participate in the Environmental Protection Agency`s (EPA) 33/50 Pollution Prevention Program and to initiate Toxic Chemical Release Inventory (TRI) reporting, pursuant to Section 313 of the Emergency Planning and Community Right-to-Know Act (EPCRA), at Department of Energy (DOE) sites. The Office of Environmental Guidance, RCRA/CERCLA Division (EH-231) issued interim guidance on March 4, 1993, entitled ``Toxic Chemical Release Inventory and 33/50 Pollution Prevention Program`` that provided instructions on implementing the Secretarial directive. As stated in the interim guidance, all DOE sites not currently reporting under EPCRA Section 313, which meet the criteria for DOE TRI reporting, will initiate reporting of all TRI chemical releases and transfers for the 1993 calendar year with the annual report due to EPA, States and a courtesy copy to EH-20 by July 1, 1994. All other DOE sites which currently report under EPCRA Section 313 will also follow the criteria for DOE TRI reporting.

  2. Novel in vitro and mathematical models for the prediction of chemical toxicity

    PubMed Central

    Shipley, Rebecca; Ellis, Marianne J.; Webb, Steve; Ward, John; Gardner, Iain; Creton, Stuart

    2013-01-01

    The focus of much scientific and medical research is directed towards understanding the disease process and defining therapeutic intervention strategies. The scientific basis of drug safety is very complex and currently remains poorly understood, despite the fact that adverse drug reactions (ADRs) are a major health concern and a serious impediment to development of new medicines. Toxicity issues account for ∼21% drug attrition during drug development and safety testing strategies require considerable animal use. Mechanistic relationships between drug plasma levels and molecular/cellular events that culminate in whole organ toxicity underpins development of novel safety assessment strategies. Current in vitro test systems are poorly predictive of toxicity of chemicals entering the systemic circulation, particularly to the liver. Such systems fall short because of (1) the physiological gap between cells currently used and human hepatocytes existing in their native state, (2) the lack of physiological integration with other cells/systems within organs, required to amplify the initial toxicological lesion into overt toxicity, (3) the inability to assess how low level cell damage induced by chemicals may develop into overt organ toxicity in a minority of patients, (4) lack of consideration of systemic effects. Reproduction of centrilobular and periportal hepatocyte phenotypes in in vitro culture is crucial for sensitive detection of cellular stress. Hepatocyte metabolism/phenotype is dependent on cell position along the liver lobule, with corresponding differences in exposure to substrate, oxygen and hormone gradients. Application of bioartificial liver (BAL) technology can encompass in vitro predictive toxicity testing with enhanced sensitivity and improved mechanistic understanding. Combining this technology with mechanistic mathematical models describing intracellular metabolism, fluid-flow, substrate, hormone and nutrient distribution provides the opportunity to

  3. Neuroprotective effects of imidazenil against chemical warfare nerve agent soman toxicity in guinea pigs.

    PubMed

    Wang, Ying; Oguntayo, Samuel; Wei, Yanling; Wood, Elisa; Brown, Ammon; Jensen, Neil; Auta, James; Guiodotti, Alessandro; Doctor, Bhupendra P; Nambiar, Madhusoodana P

    2012-03-01

    The chemical warfare nerve agent, soman irreversibly inhibits acetylcholinesterase (AChE) leading to hypercholinergy and seizures which trigger glutamate toxicity and status epilepticus ultimately resulting in neuropathology and neurobehavioral deficits. The standard emergency treatment comprising of anticholinergic, AChE reactivator and anticonvulsant does not completely protect against soman toxicity. We have evaluated imidazenil, a new anticonvulsant imidazo benzodiazepine with high affinity and intrinsic efficacy at α5-, α2-, and α3- but low intrinsic efficacy at α1-containing GABA(A) receptors and is devoid of cardiorespiratory depression, sedative/hypnoitc and amnestic actions and does not elicit tolerance and dependence liabilities unlike diazepam, for protection against soman toxicity. Guinea pigs implanted with bipotential radiotelemetry probes for recording EEG and ECG were administered with 26 μg/kg pyridostigmine bromide 30 min prior to 2× LD(50) soman exposure and 1 min later treated with a combination of 2mg/kg atropine sulfate and 25mg/kg 2-pralidoxime and various doses of imidazenil. Intramuscular administration of imidazenil, dose-dependently protected against 2× LD(50) of soman toxicity up to 1mg/kg. Further increase in the dose of imidazenil to 2.5mg/kg was less effective than 1mg/kg probably due to non-specific actions at sites other than GABA(A) receptors. Compared to vehicle group, 1mg/kg imidazenil treatment showed optimal increase in survival rate, reduction in behavioral manifestations and high power of EEG spectrum as well as neuronal necrosis. These data suggest that imidazenil is an effective anticonvulsant for medical countermeasure against soman-induced toxicity.

  4. Clouds Composition in Super-Earth Atmospheres: Chemical Equilibrium Calculations

    NASA Astrophysics Data System (ADS)

    Kempton, Eliza M.-R.; Mbarek, Rostom

    2015-12-01

    Attempts to determine the composition of super-Earth atmospheres have so far been plagued by the presence of clouds. Yet the theoretical framework to understand these clouds is still in its infancy. For the super-Earth archetype GJ 1214b, KCl, Na2S, and ZnS have been proposed as condensates that would form under the condition of chemical equilibrium, if the planet’s atmosphere has a bulk composition near solar. Condensation chemistry calculations have not been presented for a wider range of atmospheric bulk composition that is to be expected for super-Earth exoplanets. Here we provide a theoretical context for the formation of super-Earth clouds in atmospheres of varied composition by determining which condensates are likely to form, under the assumption of chemical equilibrium. We model super-Earth atmospheres assuming they are formed by degassing of volatiles from a solid planetary core of chondritic material. Given the atomic makeup of these atmospheres, we minimize the global Gibbs free energy of over 550 gases and condensates to obtain the molecular composition of the atmospheres over a temperature range of 350-3,000 K. Clouds should form along the temperature-pressure boundaries where the condensed species appear in our calculations. The super-Earth atmospheres that we study range from highly reducing to oxidizing and have carbon to oxygen (C:O) ratios that are both sub-solar and super-solar, thereby spanning a diverse range of atmospheric composition that is appropriate for low-mass exoplanets. Some condensates appear across all of our models. However, the majority of condensed species appear only over specific ranges of H:O and C:O ratios. We find that for GJ 1214b, KCl is the primary cloud-forming condensate at solar composition, in agreement with previous work. However, for oxidizing atmospheres, where H:O is less than unity, K2SO4 clouds form instead. For carbon-rich atmospheres with super-solar C:O ratios, graphite clouds additionally appear. At

  5. Chemical composition and health effects of Tartary buckwheat.

    PubMed

    Zhu, Fan

    2016-07-15

    Tartary buckwheat (Fagopyrum tataricum) contains a range of nutrients including bioactive carbohydrates and proteins, polyphenols, phytosterols, vitamins, carotenoids, and minerals. The unique composition of Tartary buckwheat contributes to their various health benefits such as anti-oxidative, anti-cancer, anti-hypertension, anti-diabetic, cholesterol-lowering, and cognition-improving. Compared with the more widely cultivated and utilised common buckwheat (F. esculentum), Tartary buckwheat tends to contain higher amounts of certain bioactive components such as rutin, therefore, showing higher efficiency in preventing/treating various disorders. This review summarises the current knowledge of the chemical composition of Tartary buckwheat, and their bio-functions as studied by both in vitro and in vivo models. Tartary buckwheat can be further developed as a sustainable crop for functional food production to improve human health.

  6. Chemical composition and health effects of Tartary buckwheat.

    PubMed

    Zhu, Fan

    2016-07-15

    Tartary buckwheat (Fagopyrum tataricum) contains a range of nutrients including bioactive carbohydrates and proteins, polyphenols, phytosterols, vitamins, carotenoids, and minerals. The unique composition of Tartary buckwheat contributes to their various health benefits such as anti-oxidative, anti-cancer, anti-hypertension, anti-diabetic, cholesterol-lowering, and cognition-improving. Compared with the more widely cultivated and utilised common buckwheat (F. esculentum), Tartary buckwheat tends to contain higher amounts of certain bioactive components such as rutin, therefore, showing higher efficiency in preventing/treating various disorders. This review summarises the current knowledge of the chemical composition of Tartary buckwheat, and their bio-functions as studied by both in vitro and in vivo models. Tartary buckwheat can be further developed as a sustainable crop for functional food production to improve human health. PMID:26948610

  7. Quantitative comparisons of acute toxicity of organic chemicals to rat and fish

    SciTech Connect

    Janardan, S.K.; Olson, C.S.; Schaeffer, D.J.

    1984-12-01

    Relationships between the acute toxicity of chemicals to fish (LC50) and rat (LD50) were analyzed using a Model II regression analysis after logarithmic transformation. (Model II regression assumes errors in both variables.) Significant correlations were found among bluegill and fathead minnow LC50S and rat LD50 values for the priority pollutants. Fathead minnow and bluegill LC50S for 48 pesticides were highly correlated. No correlations were found between fishes and rats for carbamate plus organophosphate pesticides. Correlations were obtained among all species for the combined priority pollutant plus pesticide data and for chlorinated pesticides.

  8. Methods for the assessment of the toxicity of environmental chemicals to earthworms

    SciTech Connect

    Dean-Ross, D.

    1983-03-01

    In view of the impending publication of standards for earthworm toxicity testing by the Commission of the European Communities, a review has been made of the recent literature on earthworm toxicology. Relevant studies are reviewed from the standpoints of methods used, reproducibility of results, and ability to extrapolate laboratory results to field situations. Eisenia foetida, a commonly used test species, is much less sensitive to agricultural chemicals than other, native earthworms and is of doubtful utility for extrapolating laboratory data to field conditions, but when native soil organisms are used, such extrapolations show good general agreement. Standardization of test conditions and broadening of the data base are encouraged.

  9. Composition and Chemical Variability of Ivoirian Polyalthia oliveri Leaf Oil.

    PubMed

    Ouattara, Zana A; Boti, Jean Brice; Ahibo, Coffy Antoine; Bekro, Yves-Alain; Casanova, Joseph; Tomi, Félix; Bighelli, Ange

    2016-03-01

    The chemical composition of 45 essential oil samples isolated from the leaves of Polyalthia oliveri harvested in three Ivoirian forests was investigated by GC-FID (retention indices measured on two columns of different polarities), and by (13) C-NMR, following a method developed in our laboratory. In total, 41 components were identified. The content of the main components varied drastically from sample to sample: (E)-β-caryophyllene (1.2 - 50.8%), α-humulene (0.6 - 47.7%), isoguaiene (0 - 27.9%), alloaromadendrene (0 - 24.7%), germacrene B (0 - 18.3%), δ-cadinene (0.4 - 19.3%), and β-selinene (0.2 - 18.5%). The analysis of six oil samples selected in function of their chromatographic profiles is reported in detail. The 45 oil compositions were submitted to hierarchical cluster and principal components analysis, which allowed the distinction of three groups within the oil samples. The compositions of the oils from group I (15 samples) and II (12 samples) were dominated by (E)-β-caryophyllene and α-humulene, respectively. Oil samples of group III (18 samples) needed to be partitioned into four subgroups III.1-III.4 whose compositions were dominated by alloaromadenrene, isoguaiene, germacrene B, and δ-cadinene, respectively.

  10. Comparative study of the chemical composition of wild and cultivated beans (Phaseolus vulgaris).

    PubMed

    Sotelo, A; Sousa, H; Sánchez, M

    1995-02-01

    Five wild Phaseolus vulgaris beans were compared with five cultivated Phaseolus vulgaris beans in proximate composition, total (true) protein, amino acid composition, and toxic and antinutritional factors. The wild beans contained more protein (25.5% vs. 21.7%), ash (5.15 vs. 4.15%), crude fiber (7.08% vs. 5.04%) compared to cultivated beans while the former contained less fat (0.56 vs. 0.89%) and carbohydrates (61.64 vs. 68.05%). Sulfur amino acids were found to be limiting in both groups of bean as expected; however, the cultivated beans had a higher content of the limiting amino acids. Therefore, the cultivated beans showed a better amino acid profile than the wild beans. Toxic factors were not found in either type of bean; the determinations included saponins, alkaloids, and cyanogenic glycosides. The antinutritional factors investigated were hemagglutinins (lectins) and trypsin inhibitors. The wild beans presented a higher content of trypsin inhibitors (28 TUI per mg) and lectins (9.6) than the cultivated beans did (21 TUI per mg and 7 respectively). From the chemical point of view, domestication seems to be positive; however, the better protein nutritive quality of the cultivated beans should be further confirmed by biological assays. PMID:7792267

  11. Chemical Compositional, Biological, and Safety Studies of a Novel Maple Syrup Derived Extract for Nutraceutical Applications

    PubMed Central

    2015-01-01

    Maple syrup has nutraceutical potential given the macronutrients (carbohydrates, primarily sucrose), micronutrients (minerals and vitamins), and phytochemicals (primarily phenolics) found in this natural sweetener. We conducted compositional (ash, fiber, carbohydrates, minerals, amino acids, organic acids, vitamins, phytochemicals), in vitro biological, and in vivo safety (animal toxicity) studies on maple syrup extracts (MSX-1 and MSX-2) derived from two declassified maple syrup samples. Along with macronutrient and micronutrient quantification, thirty-three phytochemicals were identified (by HPLC-DAD), and nine phytochemicals, including two new compounds, were isolated and identified (by NMR) from MSX. At doses of up to 1000 mg/kg/day, MSX was well tolerated with no signs of overt toxicity in rats. MSX showed antioxidant (2,2-diphenyl-1-picrylhydrazyl (DPPH) assay) and anti-inflammatory (in RAW 264.7 macrophages) effects and inhibited glucose consumption (by HepG2 cells) in vitro. Thus, MSX should be further investigated for potential nutraceutical applications given its similarity in chemical composition to pure maple syrup. PMID:24983789

  12. Chemical compositional, biological, and safety studies of a novel maple syrup derived extract for nutraceutical applications.

    PubMed

    Zhang, Yan; Yuan, Tao; Li, Liya; Nahar, Pragati; Slitt, Angela; Seeram, Navindra P

    2014-07-16

    Maple syrup has nutraceutical potential given the macronutrients (carbohydrates, primarily sucrose), micronutrients (minerals and vitamins), and phytochemicals (primarily phenolics) found in this natural sweetener. We conducted compositional (ash, fiber, carbohydrates, minerals, amino acids, organic acids, vitamins, phytochemicals), in vitro biological, and in vivo safety (animal toxicity) studies on maple syrup extracts (MSX-1 and MSX-2) derived from two declassified maple syrup samples. Along with macronutrient and micronutrient quantification, thirty-three phytochemicals were identified (by HPLC-DAD), and nine phytochemicals, including two new compounds, were isolated and identified (by NMR) from MSX. At doses of up to 1000 mg/kg/day, MSX was well tolerated with no signs of overt toxicity in rats. MSX showed antioxidant (2,2-diphenyl-1-picrylhydrazyl (DPPH) assay) and anti-inflammatory (in RAW 264.7 macrophages) effects and inhibited glucose consumption (by HepG2 cells) in vitro. Thus, MSX should be further investigated for potential nutraceutical applications given its similarity in chemical composition to pure maple syrup.

  13. Relation of sensory perception with chemical composition of bioprocessed lingonberry.

    PubMed

    Viljanen, Kaarina; Heiniö, Raija-Liisa; Juvonen, Riikka; Kössö, Tuija; Puupponen-Pimiä, Riitta

    2014-08-15

    The impact of bioprocessing on lingonberry flavour was studied by sensory evaluation and chemical analysis (organic acids, mannitol, phenolic compounds, sugars and volatile compounds). Bioprocessing of lingonberries with enzymes, lactic acid bacteria (LAB) or yeast, or their combination (excluding pure LAB fermentation) affected their perceived flavour and chemical composition. Sweetness was associated especially with enzyme treatment but also with enzyme+LAB treatment. Yeast fermentation caused significant changes in volatile aroma compounds and perceived flavour, whereas minor changes were detected in LAB or enzyme-treated berries. Increased concentration of organic acids, ethanol and some phenolic acids correlated with perceived fermented odour/flavour in yeast fermentations, in which increase in benzoic acid level was significant. In enzymatic treatment decreasing anthocyanins correlated well with decreased perceived colour intensity. Enzyme treatment is a potential tool to decrease naturally acidic flavour of lingonberry. Fermentation, especially with yeast, could be an interesting new approach to increase the content of natural preservatives, such as antimicrobial benzoic acid.

  14. Prediction of Chemical Carcinogenicity in Rodents from in vitro Genetic Toxicity Assays

    NASA Astrophysics Data System (ADS)

    Tennant, Raymond W.; Margolin, Barry H.; Shelby, Michael D.; Zeiger, Errol; Haseman, Joseph K.; Spalding, Judson; Caspary, William; Resnick, Michael; Stasiewicz, Stanley; Anderson, Beth; Minor, Robert

    1987-05-01

    Four widely used in vitro assays for genetic toxicity were evaluated for their ability to predict the carcinogenicity of selected chemicals in rodents. These assays were mutagenesis in Salmonella and mouse lymphoma cells and chromosome aberrations and sister chromatid exchanges in Chinese hamster ovary cells. Seventy-three chemicals recently tested in 2-year carcinogenicity studies conducted by the National Cancer Institute and the National Toxicology Program were used in this evaluation. Test results from the four in vitro assays did not show significant differences in individual concordance with the rodent carcinogenicity results; the concordance of each assay was approximately 60 percent. Within the limits of this study there was no evidence of complementarity among the four assays, and no battery of tests constructed from these assays improved substantially on the overall performance of the Salmonella assay. The in vitro assays which represented a range of three cell types and four end points did show substantial agreement among themselves, indicating that chemicals positive in one in vitro assay tended to be positive in the other in vitro assays. To help put this project into its proper context, we emphasize certain features of the study: 1) Standard protocols were used to mimic the major use of STTs worldwide--screening for mutagens and carcinogens; no attempt was made to optimize protocols for specific chemicals. 2) The 73 NTP chemicals and their 60% incidence of carcinogenicity are probably not representative of the universe of chemicals but rather reflect the recent chemical selection process for the NTP carcinogenicity assay. 3) The small, diverse group of chemicals precludes a meaningful evaluation of the predictive utility of chemical structure information. 4) The NTP is currently testing these same 73 chemicals in two in vivo STTs for chromosomal effects. 5) Complete data for an additional group of 30 to 40 NTP chemicals will be gathered on

  15. The role of chemical speciation, chemical fractionation and calcium disruption in manganese-induced developmental toxicity in zebrafish (Danio rerio) embryos.

    PubMed

    Hernández, R B; Nishita, M I; Espósito, B P; Scholz, S; Michalke, B

    2015-10-01

    Manganese (Mn) is an essential nutrient that can be toxic in excess concentrations, especially during early development stages. The mechanisms of Mn toxicity is still unclear, and little information is available regarding the role of Mn speciation and fractionation in toxicology. We aimed to investigate the toxic effects of several chemical forms of Mn in embryos of Danio rerio exposed during different development stages, between 2 and 122h post fertilization. We found a stage-specific increase of lethality associated with hatching and removal of the chorion. Mn(II), ([Mn(H2O)6](2+)) appeared to be the most toxic species to embryos exposed for 48h, and Mn(II) citrate was most toxic to embryos exposed for 72 and/or 120h. Manganese toxicity was associated with calcium disruption, manganese speciation and metal fractionation, including bioaccumulation in tissue, granule fractions, organelles and denaturated proteins.

  16. Chemical composition of volatile oil from Cinnamomum zeylanicum buds.

    PubMed

    Jayaprakasha, Guddadarangavvanahally K; Rao, Lingamallu Jaganmohan; Sakariah, Kunnumpurath K

    2002-01-01

    The hydro-distilled volatile oil of the Cinnamomum zeylanicum (C. zeylanicum) buds was analyzed using GC and GC-MS for the first time. Thirty-four compounds representing approximately 98% of the oil was characterized. It consists of terpene hydrocarbons (78%) and oxygenated terpenoids (9%). alpha-Bergamotene (27.38%) and alpha-copaene (23.05%) are found to be the major compounds. A comparison of the chemical composition of the oil was made with that of flowers and fruits.

  17. Chemical feasibility of lithium as a matrix for structural composites

    NASA Technical Reports Server (NTRS)

    Swann, R. T.; Esterling, D. M.

    1984-01-01

    The chemical compatibility of lithium with tows of carbon and aramid fibers and silicon carbide and boron monofilaments was investigated by encapsulating the fibers in liquid lithium and also by sintering. The lithium did not readily wet the various fibers. In particular, very little lithium infiltration into the carbon and aramid tows was achieved and the strength of the tows was seriously degraded. The strength of the boron and silicon carbide monofilaments, however, was not affected by the liquid lithium. Therefore lithium is not feasible as a matrix for carbon and aramid fibers, but a composite containing boron or silicon carbide fibers in a lithium matrix may be feasible for specialized applications.

  18. Unusual chemical compositions of noctilucent-cloud particle nuclei

    NASA Technical Reports Server (NTRS)

    Hemenway, C. L.

    1973-01-01

    Two sounding rocket payloads were launched from the ESRO range in Sweden during a noctilucent cloud display. Large numbers of submicron particles were collected, most of which appear to be made up of a high density material coated with a low density material. Typical electron micrographs are shown. Particle chemical compositions have been measured by use of dispersive X-ray analysis equipment attached to an electron microscope and have revealed that most of the high density particle nuclei have atomic weights greater than iron.

  19. Effect of Orimulsion{reg_sign} physical properties and chemical composition on its behavior in water

    SciTech Connect

    Ojeda, M. de; Chirinos, M.L.

    1995-12-31

    Orimulsion{reg_sign} is the trade name given to a bitumen in water, 70:30, emulsion stabilized by a nonionic surfactant and used in industrial burners and power plants as a fuel. This paper summarizes the physical properties and chemical composition of Orimulsion{reg_sign} and their effect on the self dispersing properties of the product and its behavior in water. Also, the solubility and evaporation of the light hydrocarbon fraction from the bitumen, and the toxicity and biodegradation of the fuel are discussed. Salinity of the water affects the HLB of the surfactant and the stability of the bitumen droplets making them susceptible to coalesce. BTEX content of the bitumen was determined to be relatively low, an advantage in terms of its contribution to toxicity, when compared to other similar fuels (i.e., Fuel Oil No. 6). Because of the nature of the hydrocarbons components in the bitumen, biodegradation is estimated to be around 10% of the total bitumen fraction of the formulation. Detailed chemical characterization of each one of the constituents of the Orimulsion{reg_sign} formulation will be presented.

  20. Chemical and biological properties of toxic metals and use of chelating agents for the pharmacological treatment of metal poisoning.

    PubMed

    Sinicropi, Maria Stefania; Amantea, Diana; Caruso, Anna; Saturnino, Carmela

    2010-07-01

    Exposure to toxic metals is a well-known problem in industrialized countries. Metals interfere with a number of physiological processes, including central nervous system (CNS), haematopoietic, hepatic and renal functions. In the evaluation of the toxicity of a particular metal it is crucial to consider many parameters: chemical forms (elemental, organic or inorganic), binding capability, presence of specific proteins that selectively bind metals, etc. Medical treatment of acute and chronic metal toxicity is provided by chelating agents, namely organic compounds capable of interacting with metal ions to form structures called chelates. The present review attempts to provide updated information about the mechanisms, the cellular targets and the effects of toxic metals.

  1. Public Health Risk Conditioned by Chemical Composition of Ground Water

    NASA Astrophysics Data System (ADS)

    Yankovich, E.; Osipova, N.; Yankovich, K.; Matveenko, I.

    2016-03-01

    The article studies the public health potential risk originated from water consumption and estimated on the basis of the groundwater chemical composition. We have processed the results of chemical groundwater analysis in different aquifers of Tomsk district (Tomsk Oblast, Russia). More than 8400 samples of chemical groundwater analyses were taken during long-term observation period. Human health risk assessment of exposure to contaminants in drinking water was performed in accordance with the risk assessment guidance for public health concerning chemical pollution of the environment (Russian reference number: 2.1.10.1920-04-M, 2004). Identified potential risks were estimated for consuming water of each aquifer. The comparative analysis of water quality of different aquifers was performed on the basis of the risk coefficient of the total non-carcinogenic effects. The non-carcinogenic risk for the health of the Tomsk district population due to groundwater consumption without prior sanitary treatment was admitted acceptable. A rather similar picture is observed for all aquifers, although deeper aquifers show lower hazard coefficients.

  2. Chemical vapor deposited fiber coatings and chemical vapor infiltrated ceramic matrix composites

    SciTech Connect

    Kmetz, M.A.

    1992-01-01

    Conventional Chemical Vapor Deposition (CVD) and Organometallic Chemical Vapor Deposition (MOCVD) were employed to deposit a series of interfacial coatings on SiC and carbon yarn. Molybdenum, tungsten and chromium hexacarbonyls were utilized as precursors in a low temperature (350[degrees]C) MOCVD process to coat SiC yarn with Mo, W and Cr oxycarbides. Annealing studies performed on the MoOC and WOC coated SiC yarns in N[sub 2] to 1,000[degrees]C establish that further decomposition of the oxycarbides occurred, culminating in the formation of the metals. These metals were then found to react with Si to form Mo and W disilicide coatings. In the Cr system, heating in N[sub 2] above 800[degrees]C resulted in the formation of a mixture of carbides and oxides. Convention CVD was also employed to coat SiC and carbon yarn with C, Bn and a new interface designated BC (a carbon-boron alloy). The coated tows were then infiltrated with SiC, TiO[sub 2], SiO[sub 2] and B[sub 4]C by a chemical vapor infiltration process. The B-C coatings were found to provide advantageous interfacial properties over carbon and BN coatings in several different composite systems. The effectiveness of these different coatings to act as a chemically inert barrier layer and their relationship to the degree of interfacial debonding on the mechanical properties of the composites were examined. The effects of thermal stability and strength of the coated fibers and composites were also determined for several difference atmospheres. In addition, a new method for determining the tensile strength of the as-received and coated yarns was also developed. The coated fibers and composites were further characterized by AES, SEM, XPS, IR and X-ray diffraction analysis.

  3. Vitrified metal finishing wastes I. Composition, density and chemical durability.

    PubMed

    Bingham, P A; Hand, R J

    2005-03-17

    Durable phosphate glasses were formed by vitrifying waste filter cakes from two metal finishing operations. Some melts formed crystalline components during cooling. Compositional analysis of dried, heat treated and vitrified samples was made using energy-dispersive X-ray spectroscopy, X-ray fluorescence spectroscopy, inductively-coupled plasma spectroscopy and Leco induction furnace combustion analysis. Hydrolytic dissolution, measured by an adapted product consistency test, was reduced by up to 3 orders of magnitude upon heat treatment or vitrification, surpassing the performance of borosilicate glass in some cases. This was attributed to the high levels of iron and zinc in the wastes, which greatly improve the durability of phosphate glasses. One of the wastes arose from a metal phosphating process and was particularly suitable for vitrification due to its high P2O5 content and favourable melting behaviour. The other waste, which arose from a number of processes, was less suitable as it had a low P2O5 content and during heating it emitted harmful corrosive gases and underwent violent reactions. Substantial volume reductions were obtained by heat treatment and vitrification of both wastes. Compositions and performances of some vitrified wastes were comparable with those of glasses which are under consideration for the immobilisation of toxic and nuclear wastes.

  4. Cheminformatics Analysis of EPA ToxCast Chemical Libraries to Identify Domains of Applicability for Predictive Toxicity Models and Prioritize Compounds for Toxicity Testing

    EPA Science Inventory

    An important goal of toxicology research is the development of robust methods that use in vitro and chemical structure information to predict in vivo toxicity endpoints. The US EPA ToxCast program is addressing this goal using ~600 in vitro assays to create bioactivity profiles o...

  5. Safety Issues of HG and PB as IFE Target Materials: Radiological Versus Chemical Toxicity

    SciTech Connect

    Reyes, S; Latkowski, J F; Cadwallader, L C; Moir, R W; Rio, G. D; Sanz, J

    2002-11-11

    We have performed a safety assessment of mercury and lead as possible hohlraum materials for Inertial Fusion Energy (IFE) targets, including for the first time a comparative analysis of the radiological and toxicological consequences of an accidental release. In order to calculate accident doses to the public, we have distinguished between accidents at the target fabrication facility and accidents at other areas of the power plant. Regarding the chemical toxicity assessment, we have used the USDOE regulations to determine the maximum allowable release in order to protect the public from adverse health effects. Opposite to common belief, it has been found that the chemical safety requirements for these materials appear to be more stringent than the concentrations that would result in an acceptable radiological dose.

  6. [Respiratory tract diseases caused by chemically irritating or toxic pollutants at the work site].

    PubMed

    Baur, X

    1995-05-01

    Update statistics of job-related diseases show there is still a high level in reported and also in recognised and financially compensated airway diseases caused by the action of chemically irritating or toxic substances during work. Most reported cases occur in the chemical and metal processing industries. Main triggering substances are said to be isocyanates, aerosols of pollutants produced during welding, cutting, casting or moulding (smoke), by solvents and hair dyes. Experiments prove that a variety of these noxious substances produce dose-dependent hypersensitivity of the bronchial system. Long-term monitoring of granary workers clearly points to both the possibility of and the need for early diagnosis followed by mandatory and immediate abstention from further exposure to avoid occurrence of irreversible disease patterns. Work-related health risks over and above job-conditioned diseases must be generally included in the protective measures in accordance with the new EC guidelines.

  7. Expert-system comparison of structural determinants of chemical toxicity to environmental bacteria

    SciTech Connect

    Pangrekar, J.; Rosenkranz, H.S. . Dept. of Environmental and Occupational Health); Klopman, G. . Dept. of Chemistry)

    1994-06-01

    The CASE (computer automated structure evaluation) structure-activity relational expert system was used to analyze the toxicity of a database of chemical sets to environmental bacteria (aerobic heterotrophs, nitrosomonas, methanogens, and photobacteria [Microtox [reg sign]test]). The analyses revealed that the data sets related to each of the antimicrobial activities, albeit containing a relatively small number of chemicals, are characterized by structural determinants significantly associated with the probability of antimicrobial activity, as well as with antibacterial potency. Although there were a number of similarities among the structural determinants associated with each of these antimicrobial activities, there were also features unique to each assay that presumably reflect species-specific targets of bactericidal activity. Overall the assay for antimethanogenic activity appears to be the most informative as well as the one most predictive of the activity in the other three assays.

  8. Profiling Developmental Toxicity of 387 Environmental Chemicals using EPA’s Toxicity Reference Database (ToxRefDB)

    EPA Science Inventory

    EPA's Toxicity Reference Databases (ToxRefDB) was developed by the National Center for Computational Toxicology in partnership with EPA's Office of Pesticide Programs, to store data derived from in vivo animal toxicity studies [www.epa.gov/ncct/toxrefdb/]. The initial build of To...

  9. Dynamic development of the protein corona on silica nanoparticles: composition and role in toxicity

    NASA Astrophysics Data System (ADS)

    Mortensen, Ninell P.; Hurst, Gregory B.; Wang, Wei; Foster, Carmen M.; Nallathamby, Prakash D.; Retterer, Scott T.

    2013-06-01

    The formation and composition of the protein corona on silica (SiO2) nanoparticles (NP) with different surface chemistries was evaluated over time. Native SiO2, amine (-NH2) and carboxy (-COO-) modified NP were examined following incubation in mammalian growth media containing fetal bovine serum (FBS) for 1, 4, 24 and 48 hours. The protein corona transition from its early dynamic state to the later more stable corona was evaluated using mass spectrometry. The NP diameter was 22.4 +/- 2.2 nm measured by scanning transmission electron microscopy (STEM). Changes in hydrodynamic diameter and agglomeration kinetics were studied using dynamic light scattering (DLS). The initial surface chemistry of the NP played an important role in the development and final composition of the protein corona, impacting agglomeration kinetics and NP toxicity. Particle toxicity, indicated by changes in membrane integrity and mitochondrial activity, was measured by lactate dehydrogenase (LDH) release and tetrazolium reduction (MTT), respectively, in mouse alveolar macrophages (RAW264.7) and mouse lung epithelial cells (C10). SiO2-COO- NP had a slower agglomeration rate, formed smaller aggregates, and exhibited lower cytotoxicity compared to SiO2 and SiO2-NH2. Composition of the protein corona for each of the three NP was unique, indicating a strong dependence of corona development on NP surface chemistry. This work underscores the need to understand all aspects of NP toxicity, particularly the influence of agglomeration on effective dose and particle size. Furthermore, the interplay between materials and local biological environment is emphasized and highlights the need to conduct toxicity profiling under physiologically relevant conditions that provide an appropriate estimation of material modifications that occur during exposure in natural environments.The formation and composition of the protein corona on silica (SiO2) nanoparticles (NP) with different surface chemistries was evaluated

  10. Identification and quantification of toxic chemicals by use of Escherichia coli carrying lux genes fused to stress promoters

    SciTech Connect

    Ben-Israel, O.; Ben-Israel, H.; Ulitzur, S.

    1998-11-01

    The luxCDABE bioluminescence genes of the Vibrio fischeri lux system have been used as a reporter system for different stress and regulatory promoters of Escherichia coli. Selected E. coli strains carrying lux genes fused to different promoters were exposed to various toxic chemicals, and the recorded luminescence was used for the characterization of the biologic signature of each compound. Analysis of these data with the aid of a proper algorithm allowed quantitative and qualitative assessment of toxic chemicals. Of the 25 tested chemicals, 23 were identified by this novel strategy in a 3-h procedure. This system can also be adapted for the identification of simple mixtures of toxic agents when the biologic signatures of the individual compounds are known. This biologic recognition strategy also provides a tool for evaluating the degree of similarity between the modes of action of different toxic agents.

  11. Chemical toxicity to environmental bacteria: Quantitative structure activity relationships and interspecies correlations and comparisons (Volumes I and II)

    SciTech Connect

    Blum, D.J.W.

    1989-01-01

    Toxicity data were collected for four groups of bacteria and a fish. These data were collected for four groups of bacteria and a fish. These data were used to compare and correlate the toxicities to different organisms, and to develop Quantitative Structure Activity Relationships (QSARs) correlating chemical structure with toxicity. Chemical toxicity to aerobic heterotrophic bacteria, Nitrosomonas, and methanogens were measured using serum bottle techniques in order to determine the concentration of chemical which caused 50% inhibition in microorganism's activity. Toxicity to Photobacteria phosphoreum (Microtox bacteria) and fathead minnows was also tested or data collected from the literature. Toxicants included chlorinated and other substituted benzenes and phenols, chlorinated alkanes, and a variety of additional compounds covering a range of chemical structures. Data were obtained for 50 to 130 chemicals per species. The sensitivity of the organism fell into two groups with Microtox bacteria, Nitrosomonas, and fathead minnows showing significantly greater sensitivity than aerobic heterotrophs and methanogens. Highly successful interspecies correlations were found between Microtox and each of the other species.

  12. In vitro cytotoxicity testing of 30 reference chemicals to predict acute human and animal toxicity

    SciTech Connect

    Barile, F.A.; Arjun, S.; Borges, L. )

    1991-03-11

    This study was conducted in cooperation with the Scandinavian Society of Cell Toxicology, as part of the Multicenter Evaluation for In Vitro Cytotoxicity (MEIC), and was designed to develop an in vitro model for predicting acute human and animal toxicity. The technique relies on the ability of cultured transformed rat lung epithelial cells (L2) to incorporate radiolabled amino acids into newly synthesized proteins in the absence or presence of increasing doses of the test chemical, during a 24-hr incubation. IC50 values were extrapolated from the dose-response curves after linear regression analysis. Human toxic blood concentrations estimated from rodent LD50 values suggest that our experimental IC50's are in close correlation with the former. Validation of the data by the MEIC committee shows that our IC50 values predicted human lethal dosage as efficient as rodent LD50's. It is anticipated that this and related procedures may supplement or replace currently used animal protocols for predicting human toxicity.

  13. The synergistic toxicity of the multiple chemical mixtures: implications for risk assessment in the terrestrial environment.

    PubMed

    Chen, Chen; Wang, Yanhua; Qian, Yongzhong; Zhao, Xueping; Wang, Qiang

    2015-04-01

    The combined toxicity of five insecticides (chlorpyrifos, avermectin, imidacloprid, λ-cyhalothrin, and phoxim), two herbicides (atrazine and butachlor) and a heavy metal (cadmium) has been examined with the earthworm acute toxicity test. Toxicological interactions of these chemicals in four, five, six, seven, and eight-component mixtures were studied using the combination-index (CI) equation method. In four-component and five-component mixtures, the synergistic effects predominated at lower effect levels, while the patterns of interactions found in six, seven, and eight-component mixtures displayed synergism. The λ-CY+IMI+BUT+ATR+CPF+PHO combination displayed the most strongly synergistic interaction, with CI values ranging from 0.09 to 0.15. The nature of the interaction changes with the effect level and the relevance of synergistic effects increase with the complexity of the mixture. The CI method was compared with the classical models of concentration addition (CA) and independent action (IA) and we found that the CI method could accurately predict the combined toxicity. The predicted synergism resulted from co-existence of the pesticides and the heavy metal especially at low effect levels may have important implications in risk assessment for the real terrestrial environment.

  14. Toxicity of the Organophosphate Chemical Warfare Agents GA, GB, and VX: Implications for Public Protection.

    PubMed Central

    Munro, N

    1994-01-01

    The nerve agents, GA, GB, and VX are organophosphorus esters that form a major portion of the total agent volume contained in the U.S. stockpile of unitary chemical munitions. Congress has mandated the destruction of these agents, which is currently slated for completion in 2004. The acute, chronic, and delayed toxicity of these agents is reviewed in this analysis. The largely negative results from studies of genotoxicity, carcinogenicity, developmental, and reproductive toxicity are also presented. Nerve agents show few or delayed effects. At supralethal doses, GB can cause delayed neuropathy in antidote-protected chickens, but there is no evidence that it causes this syndrome in humans at any dose. Agent VX shows no potential for inducing delayed neuropathy in any species. In view of their lack of genotoxcity, the nerve agents are not likely to be carcinogens. The overreaching concern with regard to nerve agent exposure is the extraordinarily high acute toxicity of these substances. Furthermore, acute effects of moderate exposure such as nausea, diarrhea, inability to perform simple mental tasks, and respiratory effects may render the public unable to respond adequately to emergency instructions in the unlikely event of agent releaase, making early warning and exposure avoidance important. Likewise, exposure or self-contamination of first responders and medical personnel must be avoided. Control limits for exposure via surface contact of drinking water are needed, as are detection methods for low levels in water or foodstuffs. Images Figure 2. PMID:9719666

  15. Chemical composition of milk from a herd of Norwegian goats.

    PubMed

    Brendehaug, J; Abrahamsen, R K

    1986-05-01

    The chemical composition of Norwegian bulk collected goats' milk from the University herd was analysed during one lactation period (30 weeks, 20 samples during 1983). There was considerable variation in chemical composition during the year. Fat content decreased over the first 4 months of lactation and increased during the mountain pasture period. Protein concentration decreased during the first 4 months, and then increased until the end of lactation. Lactose concentration decreased throughout lactation. Casein nitrogen (casein N) was highest at mid lactation and lowest at the beginning and end of lactation. beta-Lactoglobulin N showed the opposite trend. Citrate content showed a significantly quadratic decrease and total ash content an increase with advancing lactation. Mutual significant correlations between total P, K, Na, Ca and Mg were calculated, and all increased throughout lactation. There was significant positive correlation between concentrations of individual medium-chain fatty acids and stage of lactation. They remained more or less constant during the first part of the lactation, decreased to minima when the goats were on pasture, and increased during the last phase of lactation. Concentration of C16 fatty acid was negatively correlated with C18 and C18:1. Goat flavour intensity score and quality flavour score were highest at mid lactation, and positively correlated with the acid degree value.

  16. Description, chemical composition and noble gases of the chondrite Nogata

    NASA Astrophysics Data System (ADS)

    Shima, M.; Murayama, S.; Okada, A.; Yabuki, H.; Takaoka, N.

    1983-06-01

    Microscopic, electron-microprobe, chemical-composition, and noble-gas-isotopic-abundance studies of a 20-g sample of the ordinary chondrite Nogata are reported. The historical report of the fall of the chondrite at Nogata, Japan in the year 861 is supported by C-14 dating of the wooden box in which it has been stored in a Shinto shrine. The measurement data are presented in tables and discussed. Except for a low Fe content, the chemical composition and petrological structure of the chondrite are consistent with an L6 classification. Nogata is found to be more lightly shocked and to contain relatiely more radiogenic and spallogenic noble gases than other L chondrites. The gas-retention ages calculated for Nogata are 4.5 (He-4) and 4.7 (Ar-40) x 10 to the 9th years; the cosmic-ray-exposure age is about 4 x 10 to the 7th years. It is suggested that the metamorphism of the chondrite was completed within about 10 to the 8th years of the formation of its parent body.

  17. Chemical composition of Titan's lakes and noble gases sequestration

    NASA Astrophysics Data System (ADS)

    Cordier, D.; Mousis, O.; Lunine, J.-I.; Lavvas, P.; Lobo, L.; Ferreira, A.

    2010-04-01

    Titan is one of the most enigmatic objects in the Solar System. The presence of hydrocarbon lakes and even a global ocean have been suspected for decades. The dark features discovered by the CASSINI spacecraft are good candidates for these expected lakes (see McEwen et al. 2005 and Stofan et al. 2007). Their chemical composition has still not been measured but numerical models can give relatively accurate predictions. In the present work, we use the recent model of Titan's lakes chemical composition elaborated by Cordier et al. (2009) in light of the recent Cassini-Huygens measurements in order to investigate the possibility of sequestration of large quantities of noble gases in these liquids. Indeed, the noble gas abundances have been found to be largely in subsolar abundances in the atmosphere of Titan and the origin of this impoverishment is still poorly understood. Our preliminary results show that, under specific circumstances, at least the atmospheric depletion in krypton could be caused by its dissolution in the Titan's surface hydrocarbon liquid phase.

  18. Evidence of Coal-Fly-Ash Toxic Chemical Geoengineering in the Troposphere: Consequences for Public Health.

    PubMed

    Herndon, J Marvin

    2015-08-11

    The widespread, intentional and increasingly frequent chemical emplacement in the troposphere has gone unidentified and unremarked in the scientific literature for years. The author presents evidence that toxic coal combustion fly ash is the most likely aerosolized particulate sprayed by tanker-jets for geoengineering, weather-modification and climate-modification purposes and describes some of the multifold consequences on public health. Two methods are employed: (1) Comparison of 8 elements analyzed in rainwater, leached from aerosolized particulates, with corresponding elements leached into water from coal fly ash in published laboratory experiments, and (2) Comparison of 14 elements analyzed in dust collected outdoors on a high-efficiency particulate air (HEPA) filter with corresponding elements analyzed in un-leached coal fly ash material. The results show: (1) the assemblage of elements in rainwater and in the corresponding experimental leachate are essentially identical. At a 99% confidence interval, they have identical means (T-test) and identical variances (F-test); and (2) the assemblage of elements in the HEPA dust and in the corresponding average un-leached coal fly ash are likewise essentially identical. The consequences on public health are profound, including exposure to a variety of toxic heavy metals, radioactive elements, and neurologically-implicated chemically mobile aluminum released by body moisture in situ after inhalation or through transdermal induction.

  19. Evidence of Coal-Fly-Ash Toxic Chemical Geoengineering in the Troposphere: Consequences for Public Health

    PubMed Central

    Herndon, J. Marvin

    2015-01-01

    The widespread, intentional and increasingly frequent chemical emplacement in the troposphere has gone unidentified and unremarked in the scientific literature for years. The author presents evidence that toxic coal combustion fly ash is the most likely aerosolized particulate sprayed by tanker-jets for geoengineering, weather-modification and climate-modification purposes and describes some of the multifold consequences on public health. Two methods are employed: (1) Comparison of 8 elements analyzed in rainwater, leached from aerosolized particulates, with corresponding elements leached into water from coal fly ash in published laboratory experiments, and (2) Comparison of 14 elements analyzed in dust collected outdoors on a high-efficiency particulate air (HEPA) filter with corresponding elements analyzed in un-leached coal fly ash material. The results show: (1) the assemblage of elements in rainwater and in the corresponding experimental leachate are essentially identical. At a 99% confidence interval, they have identical means (T-test) and identical variances (F-test); and (2) the assemblage of elements in the HEPA dust and in the corresponding average un-leached coal fly ash are likewise essentially identical. The consequences on public health are profound, including exposure to a variety of toxic heavy metals, radioactive elements, and neurologically-implicated chemically mobile aluminum released by body moisture in situ after inhalation or through transdermal induction. PMID:26270671

  20. Relationship between biotransformation and the toxicity and fate of xenobiotic chemicals in fish.

    PubMed Central

    Lech, J J; Bend, J R

    1980-01-01

    Many of the biotransformation reactions which have been described for xenobiotic substances in mammals have been demonstrated in fish in both in vitro and in vivo experiments. Several of these biotransformation reactions have been shown to occur in fish at rates which are sufficient to have significant effects on the toxicity and residue dynamics of selected chemicals. Inhibition of these reactions can lead to increased toxicity and bioaccumulation factors for certain chemicals. Several classes of compounds, including some polychlorinated biphenyls, are metabolized slowly, and their disposition in fish may not be influenced to any great extent by biotransformation. Metabolites of compounds which are biotransformed rapidly may appear in certain fish tissues, and in many instances these are not accounted for by conventional residue analysis methods. Microsomal mixed-function oxidases in several species of fish have been demonstrated to be induced by specific polycyclic aromatic hydrocarbons and by exposure of fish to crude oil. Induction of these enzymes in fish can result in both qualitative and quantitative differences in the metabolic disposition of xenobiotics to which fish are exposed. PMID:6993198

  1. Evidence of Coal-Fly-Ash Toxic Chemical Geoengineering in the Troposphere: Consequences for Public Health.

    PubMed

    Herndon, J Marvin

    2015-08-01

    The widespread, intentional and increasingly frequent chemical emplacement in the troposphere has gone unidentified and unremarked in the scientific literature for years. The author presents evidence that toxic coal combustion fly ash is the most likely aerosolized particulate sprayed by tanker-jets for geoengineering, weather-modification and climate-modification purposes and describes some of the multifold consequences on public health. Two methods are employed: (1) Comparison of 8 elements analyzed in rainwater, leached from aerosolized particulates, with corresponding elements leached into water from coal fly ash in published laboratory experiments, and (2) Comparison of 14 elements analyzed in dust collected outdoors on a high-efficiency particulate air (HEPA) filter with corresponding elements analyzed in un-leached coal fly ash material. The results show: (1) the assemblage of elements in rainwater and in the corresponding experimental leachate are essentially identical. At a 99% confidence interval, they have identical means (T-test) and identical variances (F-test); and (2) the assemblage of elements in the HEPA dust and in the corresponding average un-leached coal fly ash are likewise essentially identical. The consequences on public health are profound, including exposure to a variety of toxic heavy metals, radioactive elements, and neurologically-implicated chemically mobile aluminum released by body moisture in situ after inhalation or through transdermal induction. PMID:26270671

  2. Saffron as an antidote or a protective agent against natural or chemical toxicities.

    PubMed

    Razavi, Bibi Marjan; Hosseinzadeh, Hossein

    2015-01-01

    Saffron (Crocus sativus) is an extensively used food additive for its color and taste. Since ancient times this plant has been introduced as a marvelous medicine throughout the world. The wide spectrum of saffron pharmacological activities is related to its major constituents including crocin, crocetin and safranal. Based on several studies, saffron and its active ingredients have been used as an antioxidant, antiinflammatory and antinociceptive, antidepressant, antitussive, anticonvulsant, memory enhancer, hypotensive and anticancer. According to the literatures, saffron has remarkable therapeutic effects. The protective effects of saffron and its main constituents in different tissues including brain, heart, liver, kidney and lung have been reported against some toxic materials either natural or chemical toxins in animal studies.In this review article, we have summarized different in vitro and animal studies in scientific databases which investigate the antidotal and protective effects of saffron and its major components against natural toxins and chemical-induced toxicities. Due to the lake of human studies, further investigations are required to ascertain the efficacy of saffron as an antidote or a protective agent in human intoxication.

  3. Toxicity Screening of the ToxCast Phase II Chemical Library Using a Zebrafish Developmental Assay (SOT)

    EPA Science Inventory

    As part of the chemical screening and prioritization research program of the US EPA, the ToxCast Phase II chemicals were assessed using a vertebrate screen for developmental toxicity. Zebrafish embryos (Danio rerio) were exposed in 96-well plates from late-blastula stage (6hr pos...

  4. Impact of environmental chemicals on key transcription regulators and correlation to toxicity end points within EPA's ToxCast program

    EPA Science Inventory

    Exposure to environmental chemicals adds to the burden of disease in humans and wildlife to a degree that is difficult to estimate and, thus, mitigate. The ability to assess the impact of existing chemicals for which little to no toxicity data are available or to foresee such eff...

  5. PROLIFERATION AS A KEY EVENT IN DEVELOPMENTAL TOXICITY: "CHEMICAL SCREENING IN HUMAN NEURAL STEM CELLS USING HIGH CONTENT IMAGING

    EPA Science Inventory

    New toxicity testing approaches will rely on in vitro assays to assess chemical effects at the cellular and molecular level. Cell proliferation is imperative to normal development, and chemical disruption of this process can be detrimental to the organism. As part of an effort to...

  6. Probing the ToxCastTM Chemical Library for Predictive Signatures of Developmental Toxicity - Poster at Teratology Society Annual Meeting

    EPA Science Inventory

    EPA’s ToxCast™ project is profiling the in vitro bioactivity of chemical compounds to assess pathway-level and cell-based signatures that correlate with observed in vivo toxicity. We hypothesize that cell signaling pathways are primary targets for diverse environmental chemicals ...

  7. The effects of ultraviolet-B radiation on the toxicity of fire-fighting chemicals.

    PubMed

    Calfee, Robin D; Little, Edward E

    2003-07-01

    The interactive effects of ultraviolet (UV) and fire-retardant chemicals were evaluated by exposing rainbow trout (Oncorhyncus mykiss) juveniles and tadpoles of southern leopard frogs (Rana sphenocephala) to six fire-retardant formulations with and without sodium ferrocyanide (yellow prussiate of soda [YPS]) and to YPS alone under three simulated UV light treatments. Yellow prussiate of soda is used as a corrosion inhibitor in some of the fire-retardant chemical formulations. The underwater UV intensities measured were about 2 to 10% of surface irradiance measured in various aquatic habitats and were within tolerance limits for the species tested. Mortality of trout and tadpoles exposed to Fire-Trol GTS-R, Fire-Trol 300-F, Fire-Trol LCA-R, and Fire-Trol LCA-F was significantly increased in the presence of UV radiation when YPS was present in the formulation. The boreal toad (Bufo boreas), listed as endangered by the state of Colorado (USA), and southern leopard frog were similar in their sensitivity to these chemicals. Photoenhancement of fire-retardant chemicals can occur in a range of aquatic habitats and may be of concern even when optical clarity of water is low; however, other habitat characteristics can also reduce fire retardant toxicity. PMID:12836977

  8. The effects of ultraviolet-B radiation on the toxicity of fire-fighting chemicals.

    PubMed

    Calfee, Robin D; Little, Edward E

    2003-07-01

    The interactive effects of ultraviolet (UV) and fire-retardant chemicals were evaluated by exposing rainbow trout (Oncorhyncus mykiss) juveniles and tadpoles of southern leopard frogs (Rana sphenocephala) to six fire-retardant formulations with and without sodium ferrocyanide (yellow prussiate of soda [YPS]) and to YPS alone under three simulated UV light treatments. Yellow prussiate of soda is used as a corrosion inhibitor in some of the fire-retardant chemical formulations. The underwater UV intensities measured were about 2 to 10% of surface irradiance measured in various aquatic habitats and were within tolerance limits for the species tested. Mortality of trout and tadpoles exposed to Fire-Trol GTS-R, Fire-Trol 300-F, Fire-Trol LCA-R, and Fire-Trol LCA-F was significantly increased in the presence of UV radiation when YPS was present in the formulation. The boreal toad (Bufo boreas), listed as endangered by the state of Colorado (USA), and southern leopard frog were similar in their sensitivity to these chemicals. Photoenhancement of fire-retardant chemicals can occur in a range of aquatic habitats and may be of concern even when optical clarity of water is low; however, other habitat characteristics can also reduce fire retardant toxicity.

  9. The effects of ultraviolet-B radiation on the toxicity of fire-fighting chemicals

    USGS Publications Warehouse

    Calfee, R.D.; Little, E.E.

    2003-01-01

    The interactive effects of ultraviolet (UV) and fire-retardant chemicals were evaluated by exposing rainbow trout (Oncorhyncus mykiss) juveniles and tadpoles of southern leopard frogs (Rana sphenocephala) to six fire-retardant formulations with and without sodium ferrocyanide (yellow prussiate of soda [YPS]) and to YPS alone under three simulated UV light treatments. Yellow prussiate of soda is used as a corrosion inhibitor in some of the fire-retardant chemical formulations. The underwater UV intensities measured were about 2 to 10% of surface irradiance measured in various aquatic habitats and were within tolerance limits for the species tested. Mortality of trout and tadpoles exposed to Fire-Trol?? GTS-R, Fire-Trol 300-F, Fire-Trol LCA-R, and Fire-Trol LCA-F was significantly increased in the presence of UV radiation when YPS was present in the formulation. The boreal toad (Bufo boreas), listed as endangered by the state of Colorado (USA), and southern leopard frog were similar in their sensitivity to these chemicals. Photoenhancement of fire-retardant chemicals can occur in a range of aquatic habitats and may be of concern even when optical clarity of water is low; however, other habitat characteristics can also reduce fire retardant toxicity.

  10. Chemical composition of fennel essential oil and its impact on Staphylococcus aureus exotoxin production.

    PubMed

    Qiu, Jiazhang; Li, Hongen; Su, Hongwei; Dong, Jing; Luo, Mingjing; Wang, Jianfeng; Leng, Bingfeng; Deng, Yanhong; Liu, Juxiong; Deng, Xuming

    2012-04-01

    In this study, fennel oil was isolated by hydrodistillation, and the chemical composition was determined by gas chromatography/mass spectral analysis. The antimicrobial activity of fennel oil against Staphylococcus aureus was evaluated by broth microdilution. A haemolysis assay, tumour necrosis factor (TNF) release assay, western blot, and real-time reverse transcription (RT)-PCR were applied to investigate the influence of fennel oil on the production of S. aureus virulence-related exoproteins. The data show that fennel oil, which contains a high level of trans-anethole, was active against S. aureus, with MICs ranging from 64 to 256 μg/ml. Furthermore, fennel oil, when used at subinhibitory concentrations, could dose-dependently decrease the expression of S. aureus exotoxins, including α-toxin, Staphylococcal enterotoxins (SEs) and toxic shock syndrome toxin 1 (TSST-1).

  11. Wet chemical synthesis of chitosan hydrogel-hydroxyapatite composite membranes for tissue engineering applications.

    PubMed

    Madhumathi, K; Shalumon, K T; Rani, V V Divya; Tamura, H; Furuike, T; Selvamurugan, N; Nair, S V; Jayakumar, R

    2009-07-01

    Chitosan, a deacetylated derivative of chitin is a commonly studied biomaterial for tissue-engineering applications due to its biocompatibility, biodegradability, low toxicity, antibacterial activity, wound healing ability and haemostatic properties. However, chitosan has poor mechanical strength due to which its applications in orthopedics are limited. Hydroxyapatite (HAp) is a natural inorganic component of bone and teeth and has mechanical strength and osteoconductive property. In this work, HAp was deposited on the surface of chitosan hydrogel membranes by a wet chemical synthesis method by alternatively soaking the membranes in CaCl(2) (pH 7.4) and Na(2)HPO(4) solutions for different time intervals. These chitosan hydrogel-HAp membranes were characterized using SEM, AFM, EDS, FT-IR and XRD analyses. MTT assay was done to evaluate the biocompatibility of these membranes using MG-63 osteosarcoma cells. The biocompatibility studies suggest that chitosan hydrogel-HAp composite membranes can be useful for tissue-engineering applications.

  12. Switchgrass biomass and chemical composition for biofuel in eastern Canada

    SciTech Connect

    Madakadze, I.C.; Stewart, K.; Peterson, P.R.; Coulman, B.E.; Smith, D.L.

    1999-08-01

    Switchgrass (Panicum virgatum L.) is one of several warm-season grasses that have been identified as potential biomass crops in North America. A two-year field study was conducted, on a free-draining sandy clay loam (St. Bernard, Typic Hapludalf), to characterize the growth and evaluate changes in biomass accumulation and composition of switchgrass at Montreal, QC. Three cultivars, Cave-in-Rock, Pathfinder, and Sunburst, were grown in solid stands in a randomized complete block design. Canopy height, dry matter (DM) accumulation and chemical composition were monitored biweekly throughout the growing season. Average maximum canopy heights were 192.5 cm for Cave-in-Rock, 169.9 for Pathfinder, and 177.8 for Sunburst. The respective end-of-season DM yields were 12.2, 11.5, and 10.6 Mg/ha. Biomass production among cultivars appeared to be related to time of maturation. Nitrogen concentration of DM decreased curvilinearly from 25 g/kg at the beginning of the season to 5 g/kg DM at season's end. Both acid-detergent fiber (ADF) and neutral-detergent fiber (NDF) concentrations increased to a maximum early in the season, after which no changes were detected. The average maximum values of ADF and NDF were, respectively, 647.6 and 849.0 g/kg DM for Cave-in-Rock, 669.1 and 865.2 for Pathfinder, and 661.8 and 860.9 for Sunburst. Changes in canopy height, DM accumulation, and chemical composition could all be described by predictive regression equations. These results indicate that switchgrass has potential as a biomass crop in a short-season environment.

  13. 1992 Toxic Chemical Release Inventory: Emergency Planning and Community Right-To-Know-Act of 1986 Section 313

    SciTech Connect

    Not Available

    1993-07-01

    Section 313 of the Emergency Planning and Community Right-To-Know Act of 1986 (EPCRA) requires the annual submittal of toxic chemical release information to the US Environmental Protection Agency (EPA). The following document is the July 1993 submittal of the EPCRA Toxic Chemical Release Inventory Report (Form R). Included is a Form R for chlorine and for lead, the two chemicals used in excess of the established regulatory thresholds at the Hanford Site by the US Department of Energy, Richland Operations Office and its contractors during calendar year 1992.

  14. Chemical composition of rainwater in western Amazonia — Brazil

    NASA Astrophysics Data System (ADS)

    Honório, B. A. D.; Horbe, A. M. C.; Seyler, P.

    2010-11-01

    An extensive sample study in western Amazonia, Brazil was performed over the course of one year to i) establish the natural influence of the forest, ii) determine the contribution of the vegetation and fossil fuel burning and iii) detect the geographical and temporal influences on the rainwater composition. Six sampling stations were chosen on two 1000 km-long orthogonal axes. Parintins, Itapiranga, Manaus, Tabatinga were the stations from East to West, and Boa Vista, Manaus, and Apui were the stations from North to South. The results indicate a complex control of the chemical composition of the rainwater and a rather high heterogeneity among the stations. This heterogeneity can be explained by the influence of biogenic, terrestrial dust, agriculture activities and biomass-burning aerosols, and the urban development of Manaus City with its rapid increase in the use of fossil fuel. The isotopic composition of the rainwater indicates that from the north and west sides to the south and east sides, a slight geographical and temporal gradient exists, and more δ180 enriched rainwater tends to be present in the west (Tabatinga) and in the North (Boa Vista). During the dry season a more negative δ180 rainwater was observed in Manaus and Boa Vista stations, as compared to others stations. This observation indicates the more intense evaporative contribution of rainwater as a consequence of a rapid deforestation (savannization) process in the Manaus region.

  15. Handbook of acute toxicity of chemicals to fish and aquatic invertebrates : summaries of toxicity tests conducted at Columbia National Fisheries Research Laboratory, 1965-78

    USGS Publications Warehouse

    Johnson, W. Waynon; Finley, Mack T.

    1980-01-01

    Acute toxicity is a major subject of research at Columbia National Fisheries Research Laboratory for evaluating the impact of toxic chemicals on fishery resources. The Laboratory has played a leading role in developing research technology for toxicity testing and data interpretation. In 1965-78, more than 400 chemicals were tested against a variety of invertebrates and fish species representative of both cold- and warm-water climates. The use of acute toxicity tests for assessing the potential hazard of chemical contaminants to aquatic organisms is well documented (Boyd 1957; Henderson et al. 1960; Sanders and Cope 1966; Macek and McAllister 1970). Static acute toxicity tests provide rapid and (within limits) reproducible concentration-response curves for estimating toxic effects of chemicals on aquatic organisms. These tests provide a database for determining relative toxicity of a large number of chemicals to a variety of species and for estimating acute effects of chemical spills on natural aquatic systems; they also assist in determining priority and design of additional toxicity studies. Acute toxicity tests usually provide estimates of the exposure concentration causing 50% mortality (LC50) to test organisms during a specified period of time. For certain invertebrates, the effective concentration is based on immobilization, or some other identifiable endpoint, rather than on lethality. The application of the LC50 has gained acceptance among toxicologists and is generally the most highly rated test for assessing potential adverse effects of chemical contaminants to aquatic life (Brungs and Mount 1978; American Institute for Biological Sciences 1978a). The literature contains numerous papers dealing with the acute toxicity of chemicals to freshwater organisms. However, there is a tremendous need for a concise compendium of toxicity data covering a large variety of chemicals and test species. This Handbook is a compilation of a large volume of acute toxicity

  16. Handbook of acute toxicity of chemicals to fish and aquatic invertebrates : summaries of toxicity tests conducted at Columbia National Fisheries Research Laboratory, 1965-78

    USGS Publications Warehouse

    Johnson, W. Waynon; Finley, Mack T.

    1980-01-01

    Acute toxicity is a major subject of research at Columbia National Fisheries Research Laboratory for evaluating the impact of toxic chemicals on fishery resources. The Laboratory has played a leading role in developing research technology for toxicity testing and data interpretation. In 1965-78, more than 400 chemicals were tested against a variety of invertebrates and fish species representative of both cold- and warm-water climates.The use of acute toxicity tests for assessing the potential hazard of chemical contaminants to aquatic organisms is well documented (Boyd 1957; Henderson et al. 1960; Sanders and Cope 1966; Macek and McAllister 1970). Static acute toxicity tests provide rapid and (within limits) reproducible concentration-response curves for estimating toxic effects of chemicals on aquatic organisms. These tests provide a database for determining relative toxicity of a large number of chemicals to a variety of species and for estimating acute effects of chemical spills on natural aquatic systems; they also assist in determining priority and design of additional toxicity studies.Acute toxicity tests usually provide estimates of the exposure concentration causing 50% mortality (LC50) to test organisms during a specified period of time. For certain invertebrates, the effective concentration is based on immobilization, or some other identifiable endpoint, rather than on lethality. The application of the LC50 has gained acceptance among toxicologists and is generally the most highly rated test for assessing potential adverse effects of chemical contaminants to aquatic life (Brungs and Mount 1978; American Institute for Biological Sciences 1978a).The literature contains numerous papers dealing with the acute toxicity of chemicals to freshwater organisms. However, there is a tremendous need for a concise compendium of toxicity data covering a large variety of chemicals and test species. This Handbook is a compilation of a large volume of acute toxicity data

  17. Improving ecological risk assessment of persistent, bioaccumulative, and toxic (PBT) chemicals by using an integrated modeling system - An example assessing chloroparaffins in riverine environments.

    EPA Science Inventory

    Chemical risk assessment (CRA) is primarily carried out at the screening level relying on empirical relationships between chemical properties and tested toxicity effects. Ultimately, risk to aquatic ecosystems is strongly dependent on actual exposure, which depends on chemical pr...

  18. Detection and monitoring of toxic chemical at ultra trace level by utilizing doped nanomaterial.

    PubMed

    Khan, Sher Bahadar; Rahman, Mohammed M; Akhtar, Kalsoom; Asiri, Abdullah M

    2014-01-01

    Composite nanoparticles were synthesized by eco-friendly hydrothermal process and characterized by different spectroscopic techniques. All the spectroscopic techniques suggested the synthesis of well crystalline optically active composite nanoparticles with average diameter of ∼ 30 nm. The synthesized nanoparticles were applied for the development of chemical sensor which was fabricated by coating the nanoparticles on silver electrode for the recognition of phthalimide using simple I-V technique. The developed sensor exhibited high sensitivity (1.7361 µA.mM(-1).cm(-2)), lower detection limit (8.0 µM) and long range of detection (77.0 µM to 0.38 M). Further the resistances of composite nanoparticles based sensor was found to be 2.7 MΩ which change from 2.7 to 1.7 with change in phthalimide concentration. The major advantages of the designed sensor over existing sensors are its simple technique, low cost, lower detection limit, high sensitivity and long range of detection. It can detect phthalimide even at trace level and sense over wide range of concentrations. Therefore the composite nanoparticals would be a better choice for the fabrication of phthalimide chemical sensor and would be time and cost substituted implement for environmental safety. PMID:25329666

  19. Larvicidal efficacies and chemical composition of essential oils of Pinus sylvestris and Syzygium aromaticum against mosquitoes

    PubMed Central

    Fayemiwo, Kehinde Adenike; Adeleke, Monsuru Adebayo; Okoro, Ovie Princewill; Awojide, Shola Hezekiah; Awoniyi, Ilias Olufemi

    2014-01-01

    Objective To assess the chemical composition and mosquito larvicidal potentials of essential oils of locally sourced Pinus sylvestris (P. sylvestris) and Syzygium aromaticum (S. aromaticum) against Aedes aegypti (A. aegypti) and Culex quinquefasciatus (C. quinquefasciatus). Method The chemical composition of the essential oils of both plants was determined using GC-MS while the larvicidal bioassay was carried out using different concentrations of the oils against the larvae of A. aegypti and C. quinquefasciatus in accordance with the standard protocol. Results The results as determined by GC-MS showed that oil of S. aromaticum has eugenol (80.5%) as its principal constituent while P. sylvestris has 3-Cyclohexene-1-methanol, .alpha., .alpha.4-trimethyl (27.1%) as its dominant constituent. Both oils achieved over 85% larval mortality within 24 h. The larvae of A. aegypti were more susceptible to the oils [LC50 (S. aromaticum)=92.56 mg/L, LC50(P. sylvestris)=100.39 mg/L] than C. quinquefasciatus [LC50(S. aromaticum)=124.42 mg/L; LC50(P. sylvestris)=128.00 mg/L]. S. aromaticum oil was more toxic to the mosquito larvae than oil of P. sylvestris but the difference in lethal concentrations was insignificant (P>0.05). Conclusion The results justify the larvicidal potentials of both essential oils and the need to incorporate them in vector management and control. PMID:24144127

  20. International harmonization of models for selecting less toxic chemical alternatives: Effect of regulatory disparities in the United States and Europe.

    PubMed

    Lam, Carl W; Aguirre, Muskilda P; Schischke, Karsten; Nissen, Nils F; Ogunseitan, Oladele A; Schoenung, Julie M

    2012-10-01

    The desire to reduce human exposure to toxic chemicals associated with consumer products that are marketed globally demands the creation of comparative toxicity assessment tools that are based on uniform thresholds of acceptable risks and guidelines for materials use across international boundaries. The Toxic Potential Indicator (TPI) is a quantitative model based on European Union (EU) regulatory standards for toxicity and environmental quality. Here, we describe a version of TPI that we developed with US regulatory thresholds for environmental and human health impacts of toxic materials. The customized US-based TPI (USTPI) model integrates occupational permissible exposure limits (PELs), carcinogen categories based on the scheme of the International Agency for Research on Cancer (IARC), and median effect concentration for acute aquatic toxicity (EC50s). As a case study, we compare calculated scores for EU-based TPI (EUTPI) and USTPI for a large group of chemicals including 578 substances listed in the US Toxics Release Inventory (TRI). Statistical analyses show that the median difference between USTPI and EUTPI scores do not approximate to zero, implying a general discrepancy in TPI score results. Comparison of chemical ranking with Spearman's correlation coefficient suggests a positive but imperfect rank correlation. Although some discrepancies between EUTPI and USTPI may be explained by missing toxicity information in some regulatory categories, disparities between the 2 models are associated mostly with different input parameters, i.e., different regulatory thresholds and guidelines. These results demonstrate that regional differences in regulatory thresholds for material toxicity may compromise the ideals of international agreements, such as the Globally Harmonized System (GHS) of Classification and Labeling of Chemicals, and emphasis needs to be placed on eliminating inconsistencies in hazard assessment frameworks for substances.