Temperature-dependent elimination of 2,4,6,2′, 4′-pentachloro[U-¹⁴C]biphenyl inNereis virens (Polychaeta)

Abstract

Four groups of 22 to 24 sandworms,Nereis virens, were maintained in closed aquarium systems with continuous charcoal filtration and 45 L capacity at 20% salinity and 4, 8, 12, and 16°C. The worms of 2.0 to 5.4 g initial wet weight inhabiting glass tubes were given 10 oral doses of 0.3μg 2,4,6,2′,4′-pentachloro[U-¹⁴C]biphenyl (PCB) during 10 consecutive days and were subsequently allowed to eliminate the compound for up to 45 weeks. Consumption and accumulation averaged 80.9, 78.3, 73.5, and 68.4% at the four temperatures. The elimination may be described with an exponential function and was fastest at 12°C. For instance, the times of initial 30% decrease t_e30 were 18.7, 16.8, 5.3, and 8.0 weeks at 4, 8, 12, and 16°C. Forty to 45% of the eliminated PCB were recovered from the feces, and the amounts from the feces confirmed the optimum PCB elimination at 12°C. The elimination optimum at submaximum temperatures suggests that PCB elimination byNereis virens, at least in part, is an active process. By comparison with earlier work, a dependence of the elimination times t_e30 or t_e50 on initial concentration was found thus favoring a multicompartment elimination model. Unequal PCB contents of anterior and posterior worm parts were governed by unequal lipid contents.