BIOACCUMULATION AND LACK OF TOXICITY OF OCTACHLORODIBENZOFURAN (OCDF)AND OCTACHLORODIBENZO-P-DIOXIN (OCDD) TO EARLY-LIFE STAGES OF ZEBRA FISH (BRACHYDANIO-RERIO)

Previous studies with octachlorodibenzo-p-dioxin (OCDD) and octachloro dibenzofuran (OCDF) in juvenile or adult fish exposed via water reveal ed no toxicity, despite significant bioaccumulation. With 2,3,7,8-tetr achlorodibenzo-p-dioxin (2,3,7,8-TCDD), the fish early-life stage stud y has been shown to be the most sensitive test system. Therefore, the effects of OCDD and OCDF on the early-life stages of zebra fish (Brach ydanio rerio) were determined during a flow-through test based on a co lumn generator method. No statistically significant effect of OCDD and OCDF on the survival and hatching time of the eggs was found. Further more, no effects on survival, weight, general appearance or behaviour of the larvae were observed at the end of the exposure period of 32 da ys. GC-MS analysis of test solution samples revealed geometric mean me asured concentrations of 32 (OCDD) and 34 ng/l (OCDF), respectively. C oncentrations in surviving larvae at the end of the study were 61 (OCD D) and 94 (OCDF) mu g/kg, respectively. These concentrations in zebra fish larvae were several orders of magnitude higher than concentration s in fish collected from the wild. In a review of the available labora tory fish experiments, we found a lack of biomagnification of OCDD and OCDF. We do not expect to find adverse effects of these compounds on the aquatic environment. (C) 1997 Elsevier Science Ltd.