Short-Term Bioassays in the Analysis of Complex Environmental Mixtures III


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In the four years since the 1978 Symposium on the Application of Short-Term Bioassays in the Fractionation and Analysis of Complex Environmental Mixtures the use of short-term bioassays to evaluate potential health hazards of complex environmental mixtures has substantially increased. Increased research activity has been particularly noticeable in mobile source emissions, where initial observations on the mutagenic activity of diesel particulate extracts reported at the 1978 symposium stimulated the development of major research programs in government and industry. In the absence of appropriate reference materials, the U.S. Environmental Protection Agency initiated comparative genotoxicity studies to determine the relative mutagenic and carcinogenic activity and, ultimately, the potential human health risk due to exposure to various complex emission products. Among the materials investigated were those of known health risk, such as coke oven and roofing tar emissions and cigarette smoke condensates, and those of unknown hazard, such as exhaust from diesel-and gasoline-powered vehicles. Studies on diesel emission products proved useful in short term bioassay development, as the diesel exhaust extracts were genetically active with low cellular toxicity and could be obtained in relatively large quantities. Availability of such samples aided chemical characterization, and it was eventually determined that the nitro-polynuclear aromatic hydrocarbons were among the mutagenic components of diesel exhaust particulate.




Short-Term Bioassays in the Analysis of Complex Environmental Mixtures II


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More than one hundred short-term bioassays are now available for detecting the toxicity, mutagenicity, and potential carcinogenicity of chemicals. These bioassays were developed and validated with individual compounds, and their principal application was perceived to be in evaluating the health hazard of such materials. However, man is rarely exposed to single chemicals; his exposure to hazardous chemicals is more commonly a multifactorial phenomenon. Although chemical analysis can be used to detect known hazardous compounds, it would be a staggering and expensive task to analyze large numbers of samples for all known or suspected hazardous constituents. Furthermore, the biological activity of a complex mixture cannot be reliably predicted from knowledge of its components. On the other hand, bioassays alone cannot tell us which components of complex mixtures are responsible for the biological activity detected. Thus, cost effectiveness and technical feasibility dictate stepwise and perhaps iterative application -of both chemical and biological methods in evaluating the health effects of complex environmental mixtures. Through the coupling of reliable biological detection systems with methods of chemical fractionation and analysis, it is frequently possible to isolate the individual chemical species that show biological activity. Initially, complex mixtures may be separated and bioassayed in carefully defined chemical fractions. The results of such short-term screening bioassays then may be used td guide the course of further fractionation and to determine the need for more stringent and comprehensive biological testing.




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Current Catalog


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First multi-year cumulation covers six years: 1965-70.




Multiple Stressor Effects in Relation to Declining Amphibian Populations


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For well over a decade, scientists have been trying to pinpoint the environmental cause for declining populations of amphibians in many habitats across the globe. Here, scientists and resource management professionals from a range of disciplines discuss standardized amphibian toxicity tests and meth







Nanotoxicology


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Nanomaterials - structures with characteristic dimensions between 1 and 100 nm -exhibit a variety of unique and tunable chemical and physical properties that have made engineered nanoparticles central components in an array of emerging technologies. The use of nanotechnology is increasing; however its potential adverse effects on human health are n




Bioremediation Technologies


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FROM THE INTRODUCTION This three-volume series, Bioremediation: Principles and Practice, provides state of the art description of advances in pollution treatment and reduction using biological means; identify and address, at a fundamental level, broad scientific and technological areas that are unique to the subject or theme and that must be understood if advances are to be made; and provide a comprehensive overview of new developments at the regulatory, desk-top, bench-scale, pilot scale, and full-scale levels. The series covers all media-air, water, and soil/sediment-and blends the talents, knowledge, and know-how of academic, industrial, governmental, and international contributors. The series addresses the removal of both hazardous and nonhazardous contaminants from the liquid, solid, and gas phase using biological processes. This includes the biological treatment of wastes of municipal and industrial origin; bioremediation of leachates, soils, and sediments; and biofiltration for contaminated gases.




EPA-600/8


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