Estimates of PAHs burdens in a population of ampeliscid amphipods at the head of the Mississippi Canyon (N. Gulf of Mexico)

The bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) by a dense population of ampeliscid amphipods (12,094±2499 ind m⁻²) in the head of the Mississippi Canyon at a depth of 480 m is examined and compared with estimation for amphipods from a shallow-water location, the Houston Ship Channel. The distribution of individual PAHs in sediments varies from the distribution in the organisms both in deep and shallow water, suggesting preferential uptake/depuration or uptake from pore or bottom waters. The average bioaccumulation factor (4.36±2.55) and the biota sediment accumulation factor (0.24±0.13) of total PAHs by the ampeliscid amphipods at the canyon's head are within the range reported for other benthic invertebrates. The average bioaccumulation factors are highest for dibenzothiophenes (up to 132 for C1-dibenzothiophenes) and alkylated PAHs and lowest for parent high molecular weight PAHs (HPAHs). Shallow-water amphipods are similar to deep-water amphipods in showing high preference to bioaccumulate alkylated PAHs and low preference to bioaccumulate parent HPAHs.