Fish acute toxicity measures

The USEPA OPPT cannot design training sets, nor can it measure the toxicity of industrial chemicals directly. The TSCA prescribes that the chemical industry test chemicals for toxicity thus, the OPPT is dependent upon what toxicity data are submitted to the USEPA under the TSCA. The OPPT could design a training set for a (Q)SAR such as fish acute toxicity for aromatic diazoniums, but it does not have the ability to get the chemicals in the training set tested. Thus, some (Q)SARs used by the OPPT have training sets composed of two data, one datum, or no data—just assumptions about intercept, slope, and log Kow at which no toxic effects at saturation will occur. 

Acute toxicity and short-term bioaccumulation. Studies of acute toxicity measure the lethal response after 24 or 96 h of exposure in various bodies of water. Test species should be chosen from amongst most commonly used organisms and standardized procedures should be applied. The test should include at least three different trophic levels, namely primary producers, primary consumers and secondary consumers. Normally, organisms such as green algae, daphnids and fish are utilized. 

California Department of Fish and Game denotes the State of California Department of Fish and Game, Static Acute Bioassay Procedures for Hazardous Waste Samples, 1988. EPA-600/4-90/027F denotes US Environmental Protection Agency, Methods for Measuring the Acute Toxicity of Effluent and Receiving Waters to Freshwater and Marine Organisms,... 

Kanazawa, J. (1981) Measurement of the bioconcentration factors of pesticides by fresh-water fish and their correlation with physicochemical properties of acute toxicities. Pest. Sci. 12, 417 124. 

Kaiser, K.L.E., Dixon, D.G., Hodson, PV. (1984) QSAR studies on chlorophenols, chlorobenzenes and para-substituted phenols. In QSAR in Environmental Toxicology. Kaiser, K. L. E., Ed., pp. 189-206, D. Reidel Publishing Co., Dordrecht, The Netherlands. Kamlet, M.J., Doherty, R.M., Carr, P.W., Mackay, D., Abraham, M.H., Taft, R.W. (1988) Linear solvation energy relationship. 44. Parameter estimation rules that allow accurate prediction of octanol/water partition coefficients and other solubility and toxicity properties of polychlorinated biphenyls and polycyclic aromatic hydrocarbons. Environ. Sci. Technol. 22, 503-509. Kanazawa, J. (1981) Measurement of the bioconcentration factors of pesticides by fresh-water fish and their correlation with physicochemical properties of acute toxicities. Pest. Sci. 12, 417-424. 

The ECOSAR program is used to predict the aquatic toxicity of chemicals based on their similarity of structure to chemicals for which the aquatic toxicity has been previously measured. Since 1981, the USEPA has used (Q)SARs to predict the aquatic toxicity of all new industrial chemicals (Nabholz et al. 1993 Zeeman et al. 1995). The acute toxicity of a chemical to fish (both fresh- and saltwater), water fleas... 

In the MPD-SAR study, the USEPA and the European Union compared the predicted and measured ECs for the European Union s new chemicals. The measured ECs were those reported in the European Union s MPD set of experimental toxicity summaries. When the USEPA-predicted ECs for fish and daphnid acute toxicity values were compared to the appropriate MPD-measured acute values, there was, respectively, 77% and 59% agreement, 7% and 19% underprediction, and 16% to 23% overprediction by the USEPA. Potential reasons for the under- and overprediction were investigated, and 17 of the underpredictions and 21 of the overpredictions remained unresolved. Therefore, studies that had potential problems were eliminated, and the analysis was repeated. The highest quality subset of the data indicated 87% and 79% agreement between predictions and measured values. 

T ichlobenil (2,6-dichlorobenzonitrile) is used for weed control in cranberry marshes, in nursery stock and woody plants, for pre-emergent control in crops, and for aquatic weed control. The acute toxicity of dichlobenil to fish has been measured at the Fish-Pesticide Research Laboratory in Denver the 24-hour-LC50 values are 22 p.p.m. active ingredient to bluegills (Lepomis macrochirus Rafinesque) at 24 °C. and 23 p.p.m. to rainbow trout (Salmo gairdneri Richardson) at 13°C. 

Ethyl acrylate is acutely toxic to aquatic organisms. In a series of studies with analytically measured concentrations, ethyl acrylate exhibited a 96h LC50 of 4.6 mg in freshwater fish (rainbow trout), a 48h... 

Sprague, J.B. (1969) Review paper. Measurement of pollutant toxicity to fish. I. Bioassay methods for acute toxicity. Water Res., 3, 793-821. 

Comparison of measured data on acute toxicity with calculated baseline predictions revealed that 21.5% of the compounds (53 out of 246) were at least five times more toxic towards Daphnia than estimated, whereas almost 80% had non-specific toxicity. The identification of potential outliers from the baseline QSAR models based on the set of reactive substructures derived from fish tests (section 5.1) is only partly satisfactory 19 outliers (35.8%) were recognized from their substructures and seven baseline toxicants (3.6%) were incorrectly assumed to exert excess toxicity (Jackel and Nendza, 1994). Those compounds with reactive substructures actually show excess toxicity towards Daphnia, but not all outliers are recognized. Accordingly, the set of indicators devised for fish has to be adjusted to cover different modes of action on specific targets in different organisms. 

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