The effects of copper pyrithione, an antifouling agent, on developing zebrafish embryos

Abstract

A substitute for the organotins has been the use of metal pyrithiones, principally zinc and copper (CuPT) as antifouling agents. Zebrafish, Danio rerio, embryos were exposed after fertilization to increasing concentrations of CuPT (2, 4, 8, 12, 16, 32 and 64 μg/L) for 24 h. Morphological abnormalities at 30, 96 and 120 hours post fertilization (hpf) were recorded. Abnormalities at concentrations of 12 μg/L and higher were observed. Notochords became severely twisted as concentrations increased. These distortions of the notochord originated in the tail at the lower concentrations and proceeded rostrally with increasing dose. Edema was observed in the cardiac and yolk sac regions at the 12 and 16 μg/L CuPT concentrations. Light microscopy showed disorganization of muscle fibers, disruption and distortion of the transverse myoseptum and vacuolization of the myocyte. Hatching was measured every 12 h for 5 days following the 24 h exposure. Hatching decreased in a dose dependent manner. At 120 hpf, 47 % of the 64 μg/L CuPT treated embryos hatched. Inductively coupled plasma atomic absorbance spectrophotometry (ICPAAS) revealed copper bioaccumulation in whole embryo tissue and was significantly elevated in 32 and 64 μg/L CuPT treatment groups as compared to controls. Lipid peroxidation end products were significantly increased in animals exposed to 32 and 64 μg/L of CuPT. These data demonstrate that oxidative stress may play a role in the toxicity. The abnormalities and deformities observed in fish larvae would significantly decrease survival in polluted aqua-systems and question the use of this product as an antifouling agent.