Time-course uptake and elimination of benzo(a)pyrene and its damage to reproduction and ensuing reproductive outputs of Pacific oyster, Crassostrea gigas

Abstract

The time-course of uptake and elimination of benzo(a)pyrene (BaP) for the Pacific oyster, Crassostrea gigas and reproduction damage and reproductive outputs were studied. Sexually immature C. gigas broodstock were fed for 28 days with live algae grown in four BaP solutions of 0, 50, 500, and 5,000 mu g L-1 (hereafter, control, 50, 500, and 5,000 oysters) and were subsequently conditioned to maturation by a feeding with BaP-free live algae under temperature manipulation for another 28 days. The 5,000 mu g L-1 oysters gained a steady state concentration, around 30,000 ng g(-1) d.w. for digestive gland, a week earlier compared to the 500 mu g L-1 oysters. The earlier gain or longer persistence of the steady state concentration influenced elimination of BaP, with an eliminating trend for 500 mu g L-1 oysters, while no elimination for 5,000 mu g L-1 oysters. The maternal persistence of the steady state concentration resulted in significant damages in the reproductive success and their reproductive outputs in terms of the hatching rate and larval growth, survival, and settlement. The 50 mu g L-1 oysters remained far below the steady state concentration, and showed a manifest eliminating behavior during the subsequent BaP-free 28 day maturation period. The reproductive success and initial larval events of 50 mu g L-1 oysters were comparable to those of control. However, the damage potential of the 50 mu g L-1 oysters might be more significant if their maternal exposure continued beyond 28 days, since the accumulation profile at this dose was linear.