California's quicksilver cleanup

A statewide mercury program aims to catalogue and address pollution in California waters



At best estimate, there are more than 200 derelict mercury mines in California. They’ve cumulatively left the state with at least 188 polluted water bodies.

That’s 188 sources containing mercury, a compound that can act as a neurotoxin in large enough doses. So it’s no wonder state officials are coordinating to clean up the whole mess.

IN ITS WAKE :  This photo, taken during a 2009 visit to the Klau/Buena Vista mine west of Paso Robles, highlights a pool of mining byproducts at the site. - FILE PHOTO BY STEVE E. MILLER
  • IN ITS WAKE : This photo, taken during a 2009 visit to the Klau/Buena Vista mine west of Paso Robles, highlights a pool of mining byproducts at the site.

As 2011 rounded out, the State Water Resources Control Board—the agency responsible for all waters within the state’s jurisdiction—announced a statewide program to establish thresholds for acceptable mercury concentrations in the fish tissue humans and wildlife eat, and to create a police to reduce mercury in state reservoirs. Once complete, the effort will be the first and most widely coordinated plan to develop Total Maximum Daily Loads (TMDLs) undertaken by the State Water Board. According to the board, a TMDL “is a number that represents the assimilative capacity of a receiving water to absorb a pollutant.” Translation: It’s the level after which a pollutant in local waters becomes a problem.

“The idea is, because we know we’ve got a number of impacted water bodies … we really want to see: Can we work regionally and statewide, together?” water board spokesman George Kostyrko told New Times.

To date, the state’s nine regional water boards have acted separately to develop local TMDLs and address mercury contamination within their borders. According to a 2010 list of impaired water bodies, there are 188 creeks, lakes, and reservoirs in California with a mercury problem. Region 3, which oversees waters in the Central Coast, lists six such water bodies; San Luis Obispo County is home to two sources—the Nacimiento and San Antonio reservoirs—labeled as “impaired by mercury,” according to an early fact sheet drafted for the Statewide Mercury Program.

“Mercury is obviously something that is hazardous to human health,” said Chris Rose, senior environmental scientist for the Central Coast Regional Water Quality Control Board.

But SLO County’s problems—and indeed those for the entire Region 3—are peanuts compared to other areas, Rose said. California’s biggest problem areas lie in the Central Valley (Region 5) and the San Francisco Bay Area (Region 2). As a critical component used for mining in the height of California’s gold rush, mercury was ripped out of hills and mountains, mostly in the Sierra Nevadas. In the wake of the state’s gold scramble, that area was left riddled with hundreds of abandoned mercury mines, most of which were simply left to age and spill their toxic byproducts into nearby water sources.

For example, the U.S. Environmental Protection Agency is in the middle of a multi-million dollar cleanup of the Klau/Buena Vista mine—about 12 miles west of Paso Robles—which is the suspected culprit behind Lake Nacimiento’s mercury contamination, as well as suspected contamination of Las Tablas Creek.

- STILL CURIOUS?:  More information on California’s Statewide Mercury Program is available at -

Jim Sickles, a project manager for the EPA who’s overseeing the Klau/Buena Vista cleanup, said he expects further studies of the mine, Las Tablas Creek sediments, and Nacimiento water contamination to take off in the next year or two, but a complete cleanup effort is likely as far out as 2015.

However, the Klau/Buena Vista situation is special, one that qualified for remediation through the EPA’s so-called super fund. California’s TMDL program, on the other hand, is more aimed at determining the trigger for other mercury cleanups in the state. Nationally, many eyes seem fixed on the problems associated with mercury, whether it be the remnants of historic mining operations, as in California; or airborne pollution spewed out of coal plants, as is the case in other parts of the country.

“There’s been a tremendous amount of pressure nationally to pay attention to mercury,” said Gordon Hensley of San Luis Obispo Coastkeeper. “… Here, the exposure’s confined to the water.”

Kostyrko said there’s been a strong effort by the Water Board for the past year to work collectively on mercury issues affecting California.

Technically, cleanup and enforcement efforts are aimed at methylmercury, the neurotoxic form of mercury found in the sediment of creeks, rivers, and lakes, as well as fish. Humans and wildlife that eat contaminated fish in high enough doses can suffer from the effects of mercury poisoning.

A statewide TMDL for mercury would essentially set a standard for acceptable levels in California waters, and therefore a measurement after which the state could mandate mercury cleanups and identify offenders. It might also mean new requirements for agencies that rely on permits to discharge into water bodies, such as wastewater treatment plants, Hensley said.

But the statewide TMDL program is still in its infancy. The first step will be a round of public comments and workshops, followed by a proposed TMDL for mercury, which will go out for further comment and workshops. At some point, the proposal will go to water board members for consideration. According to Kostyrko, a draft TMDL is tentatively expected for December 2013.

News Editor Colin Rigley can be reached at [email protected].


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