Biological accumulation of chlordane compounds in marine organisms from the northern North Pacific and Bering Sea

Sum of chlordane compounds (ΣCHL; cis-chlordane + trans-chlordane + cis-nonachlor + trans-nonachlor + oxychlordane) are concentrated gradually with trophic levels from zooplankton to Dall's porpoise (Phocoenoides dalli) through squid and fish. The order of bioconcentration factors (BCF: concentration in organism/concentration in seawater) in these organisms was ΣDDT (p,p′-DDE + p,p′-DDD + p,p′-DDT)>ΣCHL≦PCBs>ΣHCH (α-HCH + β-HCH + γ-HCH). Calculation for the concentration factor against food, namely biomagnification factor (BMF: concentration in organism/concentration in its food), was made for Dall's porpoise and thick-billed murre (Uria lomvia). The BMFs of these chemicals in thick-billed murre were lower than those of Dall's porpoise, suggesting the degradation and/or excretion of organochlorines through the uropygial gland with lipids. Moreover, the lowest BMF of ΣCHL in thick-billed murre among organochlorines may indicate that chlordane compounds (CHLs) are metabolized more rapidly by this seabird than Dall's porpoise.