Mercury Strategy for the Bay-Delta Ecosystem, January 26-28

Last week Dr. Monohan, Science Director at The Sierra Fund and Chico State Adjunct Professor, participated in a three day workshop in Sacramento at the Cal EPA building to update the 2003 Mercury Strategy for the Bay-Delta Ecosystem.

The first day of the workshop focused on Sources of Mercury, the second on Biogeochemistry of Mercury, and the third on Bioaccumulation of Mercury in the Foodweb. Participants included world famous mercury researchers from across the nation. To note a few, Dr. Joel Blum from the University of Michigan presented on The use of the natural abundance of stable mercury isotopes to determine the relative contribution of mercury sources to sediment and biota in the San Francisco Bay Delta System; Dr. Mark Marvin-DiPasquale from USGS presented on Controls on mercury methylation; and  Dr. Josh Ackerman from USGS presented an Overview of mercury risk to wildlife and factors influencing risk.

The largest sources of mercury to the Bay-Delta are the tributaries in both the Sierra Nevada from historic gold mines that used mercury for gold processing, and in the Coast Range from historic mercury mines. Dr. Monohan helped inform the discussion with the work that The Sierra Fund and others have been conducting to quantify the sediment and mercury loads coming from hydraulic mine sites in the Sierra.

The Sierra Fund prepared two posters for the workshop’s poster session. One, titled Mercury Abatement in Sierra Headwaters: An Overview of Two Pilot Projects, describes The Sierra Fund’s work at Malakoff Diggins State Historic Park and on the Nevada Irrigation District’s project at Combie Reservoir. The Sierra Fund and partners are working to develop these pilot projects to inform strategic mercury cleanup efforts in the Sierra.

The second poster provided an overview of The Sierra Fund’s biennial conference, “Reclaiming the Sierra 2015: The New Gold Rush,” which featured technical presentations, policy workshops, tours, and a poster session. These conferences are designed to prioritize and instigate action to clean up abandoned mines, and The Sierra Fund is looking forward to holding our next conference in the spring of 2017.

The Bay-Delta Mercury workshop participants will convene again in June 2016 to review the revised strategy. The strategy will be used by managers to set and meet regulatory requirements for mercury and by scientists to scope future research efforts to address mercury pollution.