Early life-stage toxicity in zebrafish (Danio rerio) following embryonal exposure to selected polychlorinated biphenyls.

Polychlorinated biphenyls are a widespread aquatic contaminant. In this article, specific polychlorinated biphenyl congeners were examined for embryo and early life-stage toxicity in zebrafish (Danio rerio). A set of three polychlorinated biphenyl congeners (non-ortho polychlorinated biphenyl 126, mono-ortho polychlorinated biphenyl 28 and di-ortho polychlorinated biphenyl 153) were tested. The typical lesions observed were yolk sac edema, vertebra defect, craniofacial malformations (double head, triple retina), anaxial body and inhibition of swim bladder inflation. Moreover, embryo and larval mortality increased and hatching success decreased. The severity of abnormalities and mortalities were concentration- and congener-dependent. Of the compounds tested, polychlorinated biphenyl congener 126 was found to be highly toxic to the fish embryos following exposure. The Lethal Concentration 50 values for polychlorinated biphenyl 28, polychlorinated biphenyl 126, polychlorinated biphenyl 153 calculated by probit analysis were 3.270, 1.298 and 5.375 ppm, respectively. The inhibition of swim bladder inflation was the most sensitive endpoint measured, and it is suggested that the inhibition of swim bladder inflation may be mediated by mechanism with an aryl hydrocarbon receptor activation.