Quantitative structure-activity relationships and toxicity studies of mixtures of chemicals with anaesthetic potency: Acute lethal and sublethal toxicity to Daphnia magna

Abstract

In this study quantitative structure-activity relationships (QSARs) were calculated between hydrophobicity of a group of organic chemicals with anaesthetic potency and toxicity (immobilization, mortality and inhibition of reproduction) to Daphnia magna. Differences in slopes of the high quality QSARs might be explained in terms of possible different sites of action for the three criteria of effect.The combined effects of mixtures of 5-50 chemicals on immobilization and mortality did not deviate from additivity, while the effect on reproduction deviated somewhat from it.

Fish acute toxicity syndromes and their use in the QSAR approach to hazard assessment.

“…(1) (Fig. 2): log LC50 = -0.94 logP + 0.94 log (0.000068 logP + 1) -1.25 (1) (r2 = 0.9936) Similar relationships with the guppy (33) and Daphnia magna (34) have been reported as well. Also presented in Figures 1 and 2 is the relationship between water solubility and log P, which delineates the "aquatic toxicity space" as that region below water solubility; i.e., acute toxicity cannot be measured under equilibrium conditions at concentrations greater than aqueous solubility (25).…”

Joint effects of a mixture of 14 chemicals on mortality and inhibition of reproduction of Daphnia magna

“…Also with other chemicals a reduced joint toxicity was found in experiments with inhibition of reproduction as a parameter in comparison with mortality experiments (Hermens et al, 1984a). Therefore, it cannot be excluded that the potential for addition is reduced when more specific sublethal effects are studied, as suggested in the EIFAC report (EIFAC, 1980).…”

“…The acute mortality to the guppy (K6nemann, 1981) and to Daphnia magna (Hermens et al, 1984a) of mixtures of 50 non-reactive, non-ionized organic chemicals, related in action to the volatile anaesthetics, could be predicted successfully with this concentration addition model. Also in mixtures of chlorophenols (Kfnemann, 1981) and anilines (Hermens et al, 1984b), the joint acute mortality was concentration additive.…”

Modeling Acute and Chronic Toxicity of Nonpolar Narcotic Chemicals and Mixtures toCeriodaphnia dubia

“…Regression models from other published data on D. magna had similar slopes (P"0.7643), but were not coincident (P"0.0152). When constrained to the common slope (0.8530), the intercept for the data of Calamari et al (1983;0.1272) was similar to that for this study (!0.0541), while intercepts for the data of Hermens et al (1984) and Richter et al (1983) were significantly higher (intercept"0.8400, P"0.0009, and intercept:0.6838, P"0.0023, respectively). The maximum difference in intercepts (0.9481 between this study and that of Hermens et al, 1984) corresponds to variation in chronic response by a factor of 8.87 for the different experiments.…”