COMMENT ON 'THE LONG-TERM FATE OF POLYCHLORINATED BIPHENYLS IN SAN FRANCISCO BAY, (USA)'

摘要

In a recent paper published in Environmental Toxicology and Chemistry (ET&C), Davis presents a simple mass balance model of poly chlorinated biphenyls (PCBs) in the water and sediment of San Francisco Bay. The author uses the model to derive conclusions about the dominant processes affecting PCBs and the relationship between the recovery of the bay and external loads. As discussed below, a realistic analysis of long-term PCB fate and transport in the bay must include the effects of tidal exchange between the bay and the ocean. Davis's model neglects tides and the impact of ocean water that enters through the Golden Gate on PCB levels in the bay, leading him to reach conclusions that cannot be reconciled with evidence of ongoing natural recovery in the bay. We present a revised version of the author's model that accounts for tides and is more representative of the system.