RMP Sponsors Forum on Methlymercury in Restored Marshes

Forum on Science to Support Management of Methylmercury in Restored Tidal Marshes

The RMP sponsored a forum to review information and information needs relating to managing methylmercury in restored tidal marshes in San Francisco Bay. The forum was held to address a lack of consensus on the best approach for monitoring methylmercury and using monitoring data in decision-making. The forum addressed the state of knowledge regarding the role wetland restoration and management play in methylmercury impairment locally and regionally, and helped inform decision-making by the San Francisco Bay Regional Water Quality Control Board and other agencies.

This discussion was structured around management questions and hypotheses of interest to the Regional Water Board. A panel of invited experts, including Dr. Jim Wiener of the University of Wisconsin at LaCrosse, Dr. Rob Mason from the University of Connecticut, and Dr. Jeremy Lowe from ESA, provided valuable input. A series of presentations summarized existing knowledge and set the stage for discussing the questions and hypotheses of interest.

The group reached consensus on some key points:
• There will likely be a short-term spike in methylmercury within the project following restoration activities. However there was no consensus around the long-term effect on levels of concern in biota - long-term monitoring would be needed to evaluate this.
• A regional increase in methylmercury in the Bay because the amount of methylmercury exported will be a small part of the overall mass balance.
• The increased methylmercury risk to marsh and salt pond wildlife (local effects) may still be substantial.
• Biosentinel monitoring and process studies are both needed: biosentinels to generate hypotheses, and process studies to test hypotheses.
• In order to understand how to design restoration projects to reduce methylmercury risk we would need to invest in research and pilot studies.

A full summary of the meeting, the Powerpoints that were presented, and other meeting materials are available on the web page for the event.