In the field of aquatic toxicology, quantitative structure-activity relationships (QSARs) have developed as scientifically credible models for predicting the toxicity of chemicals when little or no empirical data are available. In recent years, 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 objective of this research was to develop procedures that relate modes of acute toxic action in the fathead minnow (Pimephales promelas) to chemical structures and properties. An empirically derived database for diverse chemical structures of acute toxicity and corresponding modes of toxic action was developed through joint toxic action studies, the establishment of toxicodynamic profiles, and behavioral and dose-response interpretation of 96-h LC50 tests. Using the results from these efforts, as well as principles in the toxicological literature, approximately 600 chemicals were classified as narcotics (three distinct groups), oxidative phosphorylation uncouplers, respiratory inhibitors, electrophiles/proelectrophiles, acetylcholinesterase inhibitors, or central nervous system seizure agents. Using this data set, a computer-based expert system has been established whereby chemical structures are associated with likely modes of toxic action and, when available, corresponding QSARs.

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Predicting modes of toxic action from chemical structure: Acute toxicity in the fathead minnow (Pimephales promelas)

Metal bioavailability and toxicity to fish in low-alkalinity lakes: A critical review.

Preface. 1. Introduction. 2. Sources of Aquatic Pollution. 3. Bioconcentration in Fish Tissue. 4. Introduction to Fish Reproduction. 5. Disruption of Hypothalamic and Pituitary Function. 6. Disruption of Male Reproductive Function. 7. Disruption of Female Reproductive Function. 8. Disruption in Eggs, Embryos, Larvae and Juvenile Fish. 9. Disruption of Liver Function. 10. Disruption of Thyroid and Interrenal Function. 11. The Fish-Wildlife-Human Connection. Appendix. References. Species Key. Index.

Endocrine Disruption in Fish

Behavioral toxicity tests, if properly designed, can be used in conjunction with standard acute lethality tests, chronic full or partial life cycle tests, and early life stage toxicity tests to add ecological realism to toxicant assessments and the regulations made as an outgrowth of these assessments. Changes in certain fish behaviors, especially cough rate and avoidance reactions, are very sensitive indicators of sublethal exposure to metals. Other tests involving predator avoidance, feeding behavior, learning, social interactions, and a variety of locomotor behaviors show promise but have been insufficiently studied to judge their sensitivity or utility. No behavioral tests have been standardized and few have been verified in the field. We discuss the behavioral tests that have been used with metals, examine their sensitivity compared with standard laboratory toxicity tests, and assess the potential ecological significance of the behavioral changes observed.

Effects of metals on fish behavior: a review

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Nutrient Requirements Of Fish

Three generations of brook trout (Salvelinus fontinalis) were exposed to several concentrations of total cadmium (0.06–6.4 μg Cd/liter). Significant numbers of first- and second-generation adult males died during spawning at 3.4 μg Cd/liter. This concentration also significantly retarded growth of juvenile second- and third-generation offspring. The maximum acceptable toxicant concentration (MATC) for brook trout exposed to cadmium in Lake Superior water (hardness 44 mg/liter as CaCO 3, pH 7–8) lies between 1.7 and 3.4 μg Cd/liter. Cadmium-residue analyses of kidney, liver, gill, gonad, spleen, muscle, and red blood cells frown first- and second- generation trout indicated that kidney, liver, and gill tissue accumulated the greatest amounts of cadmium at each water exposure concentration. No significant increases in cadmium were measured in edible muscle at any of the cadmium water concentrations tested. Cadmium residues in kidney, liver, and gill tissue of fish frown all exposure concentrations ...

Toxic Effects of Cadmium on Three Generations of Brook Trout (Salvelinus fontinalis)

Laboratory brook trout were used to evaluate, refine, or develop biochemical procedures for the analysis of fish blood Analytical values were obtained for the following blood properties: total and differential leucocytes and erythrocytes; erythrocyte and plasma proteins (by electrophoresis); plasma refractive index; erythrocyte sedimentation rate; erythrocyte osmotic fragility; blood surface tension and density; haemoglobin; and packed cell volume These blood factors are discussed with reference to fish health and disease and to changes caused by deleterious quantities of water pollutants

Cells, proteins, and certain physical‐chemical properties of brook trout (Salvelinus fontinalis) blood

Effect of selected environmental pollutants and other chemicals on the activity of urease (in vitro).

Acetylenic and allylic alcohols have been reported to be 20 to 5,000 times more acutely toxic to fathead minnows (Pimephales promelas) than would be expected from a narcosis-based mechanism of action. The greater-than-expected toxicity of these alcohols has been proposed to be a result of metabolic activation to the corresponding reactive α,β-unsaturated aldehydes or allene derivatives. Using purified horse liver and rainbow trout (Oncorhynchus mykiss) hepatic cytosol alcohol dehydrogenase (ADH) preparations, the propensity of a series of acetylenic and allylic alcohols to inhibit enzyme activity, in both the presence and the absence of reduced glutathione, was ascertained. Those alcohols classified as reactive toxicants in acute toxicity tests were generally effective inhibitors of ADH activity, whereas those alcohols classified as narcotics were generally ineffective inhibitors. The results from this study suggest that (a) acetylenic and allylic alcohols may be metabolically activated to reactive species and (b) to compare and ultimately predict the toxicity of these unsaturated alcohols, their rates of metabolic activation and the reactivity of the subsequently produced aldehydes must be quantified.

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Inhibition of alcohol dehydrogenase activity by acetylenic and allylic alcohols: Concordance with in vivo electrophile reactivity in fish

Approximate weights offish were calculated from length and width measurements of their photographic images. In the calculations we employed the formula Wt = KLW², where Wt = weight (g); K = proportionality factor, derived from a subsample of the population under study; L = length (cm); and W = width (cm). When tested against true weights, the derived weights had a mean error of ±8.6%.

Glenn M. Christensen

Papers

Toxic Effects of Cadmium on Three Generations of Brook Trout (Salvelinus fontinalis)

Cells, proteins, and certain physical‐chemical properties of brook trout (Salvelinus fontinalis) blood

Effect of selected environmental pollutants and other chemicals on the activity of urease (in vitro).

Inhibition of alcohol dehydrogenase activity by acetylenic and allylic alcohols: Concordance with in vivo electrophile reactivity in fish

Estimation of Live Fish Weight by Photography