Ecotoxicological evaluation of 4-aminobiphenyl using a test battery

Experimental bioassays are currently used in ecotoxicology and environmental toxicology to provide information for risk assessment evaluation of new chemicals and to investigate their effects and mechanisms of action; in addition, ecotoxicological models are used for the detection, control, and monitoring of the presence of pollutants in the environment. As a single bioassay will never provide a full picture of the quality of the environment, a representative, cost-effective, and quantitative test battery should be developed. In this study, the effects of 4-aminobiphenyl (4-ABP) were investigated using a battery of ecotoxicological model systems, including immobilization of Daphnia magna, development of zebrafish embryos, and inhibition of mammalian cell proliferation. The growth inhibition effects of 4-ABP were assessed on mouse connective tissue fibroblast cells (L929 cells) and human hepatocelluar carcinoma cells (HepG2 cells) by using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-trazolium bromide reduction assay. The results reveal that 4-aminobiphenyl is toxic for aquatic organisms and mammalian cells. The system most sensitive to 4-aminobiphenyl is D. magna immobilization, followed by development of zebrafish embryos, and inhibition of cell proliferation. L929 and HepG2 cell growth inhibition bioassays show low sensitivity. These findings indicate that a single model for the possible harmful effect of 4-ABP has its limitations; only a test battery, composed of bioassays on different species, can provide an accurate assessment of the action of 4-ABP in the whole environment.