Metabolism of hexachlorobenzene in the fry of steelhead trout, Salmo gairdneri (Oncorhynchus mykiss)

Dietary intake of hexachlorobenzene (HCB) by steelhead trout (Salmo gairdneri) fry required 12 to 14 days to reach steady state equilibrium. On cessation of feeding, half of the absorbed HCB was eliminated in seven days and half of the remaining HCB in the following three days. The fry (10-gm body wt) during the exposure phase metabolized HCB to very low levels of pentachlorophenol (PCP), which was conjugated further with glucuronic acid. PCP was also produced in vitro by hepatic microsomal P-450 of the larger fry. The small 1-gm fry at the end of the experiment (20 days post-exposure) showed traces of only 2,5-dichloro-, 2,3,6,-trichloro- and 2,4,5-trichloro-phenol.