Quantifying the fate of mercury in the Great Lakes Basin: toward an ecosystem approach.

We argue that the need to reduce human exposure to mercury in the Great Lakes Basin and thus reduce the risk of adverse effects can be accomplished only by reducing the quantity of all mercury species cycling in the ecosystem. It is pointed out that much can be learned from experiences with PCBs. PCB concentrations and exposures have been reduced, in part, because a clear picture has been established of relative sources and PCB' s environmental fate in the form of mass balance models, which document the "big picture" of PCB behavior at a range of scales. It is suggested that a similar strategy is needed for mercury as part of the effort to protect human health throughout the entire Great Lakes ecosystem.