Download or read book Microbial Toxicity of Mixtures of Organic Chemicals Modeling and Validation for Non Uniform Mixtures written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Joint effects of binary and multi-component, uniform and non-uniform mixtures assayed in our microbial toxicity studies were found to be simply additive, or essentially simply additive. These results are in agreement with the conclusions reported in the literature on fish toxicity studies. Using QSAR models to predict single chemical toxicity and assuming perfect simple additivity, concentrations of the components in mixtures that would cause 50% inhibition were predicted. These predicted concentrations agreed well with the measured values over nearly three orders of magnitude with r2=0.80 at p=0.0001% for 610 sets of data points from 40 different mixtures on two different microorganisms. The overall average factor of error of these predictions was 1.82. The results of this study provide an impetus to utilize the large number of single chemical QSAR models reported in the literature by other researchers in predicting joint effects in the aquatic toxicology and ecotoxicological fields.

Download or read book Microbial Toxicity of Non Uniform Mixtures of Xenobiotic Chemicals written by and published by . This book was released on 1997 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: The scope of work under the AASERT grant included measuring and analysis of toxicity data for additional chemicals than the parent grant and to validate models developed under the parent grant. A total of 35 new chemicals were assayed using the procedures developed under the parent grant. Non-uniform, multi-component mixture studies were completed and analyzed using the new modeling approach developed during the previous period. A new statistical modeling approach to analyze nonuniform mixture has been formulated and tested on data generated under the parent grant.

Download or read book Joint Toxicity of Non uniform Mixtures of Organic Chemicals to Microorganisms written by Sheng Xu and published by . This book was released on 1997 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling Joint Effects of Mixtures of Chemicals on Microorganisms Using Quantitative Structure Activity Relationship Techniques Phase 3 written by and published by . This book was released on 1994 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: A laboratory procedure was developed to measure the toxicity of 35 organic chemicals in the soil medium using the respirometeric technique. These toxicity assays were carried out using a commercially available surrogate test culture of microorganisms. Reproducibility test were done on 12 of the chemicals yielding an average standard deviation of 0.034 and a coefficient of variation of 0.08. These tests were also repeated at different moisture holding capacities of 33%, 50%, 80% and 100% for six chemicals yielding an average standard deviation of 0.20 and coefficient of variation of 0.27. Using a part of the experimental IC50 results as a training set, Quantitative structure Activity Relationship (QSAR) models were developed to predict the toxicity of 12 chemicals in the testing set. Joint toxicity of 35 different combinations of mixtures in the soil were also measured at equitoxic ratios. The joint effects in there mixtures were analyzed for simple additivity. Result indicate that the test chemicals exhibited simple additivity when acting jointly in a uniform mixture. A QSAR approach is proposed to predict mixture toxicity based on single chemical QSAR models.

Download or read book Environmental Modeling written by Vijay P. Singh and published by Water Resources Publication. This book was released on 1999 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling Joint Effects of Mixtures of Chemicals on Microorganisms Using Quantitative Structure Activity Relationships written by and published by . This book was released on 1992 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: Toxicity of 50 organic chemicals to microorganisms was determined using the respirometeric approach. Using this experimental database, models for predicting toxicity (IC50 values) were developed using QSAR techniques. Toxicity measurements were also made for ten binary mixtures, and sixteen multi-component mixtures. The joint effects of organic chemicals in mixtures were analyzed by three different approaches. Using the QSAR model developed from single chemical studies, an approach was developed to analyze and predict joint effects of chemicals in mixtures. The results of this study indicate that the joint effects could be considered simply additive for the different classes of chemicals tested.

Download or read book Mixture Toxicity written by Cornelis A. M. van Gestel and published by CRC Press. This book was released on 2016-04-19 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last decade and a half, great progress has been made in the development of concepts and models for mixture toxicity, both in human and environmental toxicology. However, due to their different protection goals, developments have often progressed in parallel but with little integration. Arguably the first book to clearly link ecotoxicology an

Download or read book EPA Publications Bibliography written by United States. Environmental Protection Agency and published by . This book was released on 1985 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bioavailability of Contaminants in Soils and Sediments written by National Research Council and published by National Academies Press. This book was released on 2003-05-03 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bioavailability refers to the extent to which humans and ecological receptors are exposed to contaminants in soil or sediment. The concept of bioavailability has recently piqued the interest of the hazardous waste industry as an important consideration in deciding how much waste to clean up. The rationale is that if contaminants in soil and sediment are not bioavailable, then more contaminant mass can be left in place without creating additional risk. A new NRC report notes that the potential for the consideration of bioavailability to influence decision-making is greatest where certain chemical, environmental, and regulatory factors align. The current use of bioavailability in risk assessment and hazardous waste cleanup regulations is demystified, and acceptable tools and models for bioavailability assessment are discussed and ranked according to seven criteria. Finally, the intimate link between bioavailability and bioremediation is explored. The report concludes with suggestions for moving bioavailability forward in the regulatory arena for both soil and sediment cleanup.

Download or read book Toxicological Profile for Polycyclic Aromatic Hydrocarbons written by and published by . This book was released on 1995 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Methods for Measuring the Toxicity and Bioaccumulation of Sediment associated Contaminants with Freshwater Invertebrates written by and published by . This book was released on 2000 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Soil Ecotoxicology written by Joseph Tarradellas and published by CRC Press. This book was released on 1996-12-23 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soils are receptacles for a wide range of hazardous chemicals generated by human activities. Whether or not this contamination is deliberate, accurate toxicity assessments are important for health and economic reasons. Soil Ecotoxicology discusses the sources, fate, and transport of hazardous chemicals in soils. The fate (biodegradation and modeling) and the potential impacts of pesticides on soil ecosystems are emphasized, and methodologies for performing toxicity assessments are provided.

Download or read book OECD Guidelines for Testing of Chemicals written by Organisation for Economic Co-operation and Development and published by Organisation for Economic Co-operation and Development ; [Montréal : Renouf]. This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Methods for Assessing the Toxicity of Sediment associated Contaminants with Estuarine and Marine Amphipods written by and published by . This book was released on 1994 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book EPA Publications Bibliography written by and published by . This book was released on 1985 with total page 814 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Toxicological Profile for Tin and Compounds written by and published by . This book was released on 1992 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Toxicological Profile for Acrolein written by and published by . This book was released on 2007 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: