Differences between freshwater and seawater killifish (Oryzias latipes) in the accumulation and elimination of pentachlorophenol

Freshwater and seawater acclimated (FWA and SWA) killifish (Oryzias latipes) were exposed to pentachlorophenol (PCP) for 3–10 days. Uptake and clearance rates of FWA and SWA killifish were determined. The estimated bioaccumulation factors (BCF) of PCP for FWA and SWA killifish were 1680 and 370, respectively. The smaller uptake rate and faster clearance rate resulted in the lower BCF for SWA killifish. Fresh- and seawater killifish excreted the PCP metabolites, the glucuronide and sulfate conjugates of PCP; the major metabolite of freshwater killifish was PCP sulfate; for seawater acclimated fish, it was PCP glucuronide. The greater excretion of PCP glucuronide by seawater killifish may be responsible for the rapid elimination of PCP. PCP accumulation in killifish decreased with higher pH levels in both freshwater and seawater environments, but these differences were less than the effect of salinity. The results indicate that salinity can affect the accumulation and elimination of environmental pollutants in killifish.