Gilman D. Veith

Bio: Gilman D. Veith is an academic researcher from United States Environmental Protection Agency. The author has contributed to research in topics: Modes of toxic action & Acute toxicity. The author has an hindex of 35, co-authored 78 publications receiving 4000 citations. Previous affiliations of Gilman D. Veith include University of Minnesota.

Structure–Toxicity Relationships for the Fathead Minnow, Pimephales promelas: Narcotic Industrial Chemicals

Abstract: Narcosis is a reversible state of arrested activity of protoplasmic structures caused by a wide variety of organic chemicals. This nonspecific mode of toxic action was found predominant in acute to...

Rules for distinguishing toxicants that cause type I and type II narcosis syndromes.

Abstract: Narcosis is a nonspecific reversible state of arrested activity of protoplasmic structures caused by a wide variety of organic chemicals. The vast majority of industrial organic chemicals can be characterized by a baseline structure-toxicity relationship as developed for diverse aquatic organisms, using only the n-octanol/water partition coefficient as a descriptor. There are, however, many apparent narcotic chemicals that are more toxic than baseline narcosis predicts. Some of these chemicals have been distinguished as polar narcotics. Joint toxic theory and isobole diagrams were used to show that chemicals strictly additive with phenol were generally more toxic than predicted by narcosis I models and characterized by a different mode of action called narcosis II syndrome. This type of toxicity is exemplified by certain amides, amines, phenols, and nitrogen heterocycles. Evidence is provided that suggests that narcosis II syndrome may result from the presence of a strong hydrogen bonding group on the molecule, and narcosis I syndrome results from hydrophobic bonding of the chemical to enzymes and/or membranes. This shift in toxic action is apparently indistinguishable for narcotic chemicals with log P greater than about 2.7. General rules for selecting the appropriate models are proposed.

An evaluation of using partition coefficients and water solubility to estimate bioconcentration factors for organic chemicals in fish

Abstract: Bioconcentration factors (BCF), water solubilities, and n-octanol-water partition coefficients are presented for 28 organic chemicals. The chemicals studied were of low to moderate lipid solubility, with bioconcentration factors ranging from 2 to 3400. The equation log BCF = 0.76 log P - 0.23 is proposed for estimating the bioconcentration factor from the partition coefficient. The cost-effectiveness of measuring and estimating the partition coefficient and water solubility of organic chemicals is also discussed. The cost of measuring these two parameters was approximately $1000. Partition coefficients calculated from data in the literature at a cost of $2.00 per chemical differed from the measured values by only 7.2 percent. The water solubilities calculated from the partition coefficient differed from the measured solubilities by 17.2 percent for those chemicals with a partition coefficient greater than 100.

Organic geochemistry of natural waters

Abstract: This book is written as a reference on organic substances in natural waters and as a supplementary text for graduate students in water chemistry. The chapters address five topics: amount, origin, nature, geochemistry, and characterization of organic carbon. Of these topics, the main themes are the amount and nature of dissolved organic carbon in natural waters (mainly fresh water, although seawater is briefly discussed). It is hoped that the reader is familiar with organic chemistry, but it is not necessary. The first part of the book is a general overview of the amount and general nature of dissolved organic carbon. Over the past 10 years there has been an exponential increase in knowledge on organic substances in water, which is the result of money directed toward the research of organic compounds, of new methods of analysis (such as gas chromatography and mass spectrometry), and most importantly, the result of more people working in this field. Because of this exponential increase in knowledge, there is a need to pull together and summarize the data that has accumulated from many disciplines over the last decade.

Adverse outcome pathways: A conceptual framework to support ecotoxicology research and risk assessment

Abstract: Ecological risk assessors face increasing demands to assess more chemicals, with greater speed and accuracy, and to do so using fewer resources and experimental animals. New approaches in biological and computational sciences may be able to generate mechanistic information that could help in meeting these challenges. However, to use mechanistic data to support chemical assessments, there is a need for effective translation of this information into endpoints meaningful to ecological risk-effects on survival, development, and reproduction in individual organisms and, by extension, impacts on populations. Here we discuss a framework designed for this purpose, the adverse outcome pathway (AOP). An AOP is a conceptual construct that portrays existing knowledge concerning the linkage between a direct molecular initiating event and an adverse outcome at a biological level of organization relevant to risk assessment. The practical utility of AOPs for ecological risk assessment of chemicals is illustrated using five case examples. The examples demonstrate how the AOP concept can focus toxicity testing in terms of species and endpoint selection, enhance across-chemical extrapolation, and support prediction of mixture effects. The examples also show how AOPs facilitate use of molecular or biochemical endpoints (sometimes referred to as biomarkers) for forecasting chemical impacts on individuals and populations. In the concluding sections of the paper, we discuss how AOPs can help to guide research that supports chemical risk assessments and advocate for the incorporation of this approach into a broader systems biology framework.