Mercury in San Francisco Bay can become a problem if it accumulates in food webs to concentrations that adversely affect people or wildlife. Some studies indicate that mercury bioaccumulation correlates to wetland acreage at the ecosystem scale. Wetland restoration might therefore represent a threat to ecosystem health. Assessing this threat requires understanding the geography of mercury availability and uptake into food webs within and among wetlands for key species at scales that can be translated into restoration design or management actions. Biosentinel species are part of a cost-effective approach to practical risk assessment. We are developing a suite of habitat-specific biosentinels that reflect specific food-web compartments of intertidal sub-habitats. These biosentinels indicate differences in mercury risk across scales of time and space that are relevant to intertidal restoration design and management. Initial results from three years of monitoring and process studies will be presented that indicate how landscape setting, historical land use, geomorphology, plant community composition, and population ecology influence the definition and solution of the mercury problem.