Toxic bullets

City testers check toxicity around gun club.

By Jo Stanley | Staff Writer
Published on Monday, August 2, 2004

Waters are rising at Lake Merced, bringing fresh possibilities to the popular lake but also new questions about whether lead accumulated over decades may cause contamination of The City's emergency water supply.

Lake Merced, which consists of four lakes covering roughly 250 acres, is intended to be available for drinking water in dire situations such as earthquake or drought -- just as it was during the late 1800s before Hetch Hetchy was constructed.

But lead accumulated for half a century may cause contamination as it washes up from shoreline mud near the Pacific Rod and Gun Club. The gun club, which has been leasing property along 1,500 feet of the South Lake since 1939, stopped using lead shot in the early 1990s. The majority of the residue has either settled into the soil or been covered over by layers of vegetation, clay pigeons or the newer steel shot onshore, according to the San Francisco Public Utilities Commission.

Since lead is a heavy metal and doesn't dissolve easily in water, there's hope it may not pose a health hazard to aquatic birds traversing the Pacific Flyway, trout swimming in the water, or humans who come for picnics and boating. In fact, according to SFPUC, that's exactly what a 1993 study indicated, leading to a finding by the California Fish and Game Department that no action was needed on The City's part.

However, the PUC is doing some voluntary testing for the highly toxic metal around certain parts of the lake this month, before proceeding with an ambitious plan to raise the water level by 5 feet more over the coming decade or so.

"We're mostly looking at the sediments," said the SFPUC's Greg Bartow. "It hasn't been used in 74 years but we wouldn't want lead levels to exceed drinking water standards."

He added that testing over recent years in the middle of South Lake has indicated those levels are dramatically lower than the minimum 50 parts per billion -- more like 0.2 parts per billion or lower.

Biologists are planning to set out in boats throughout the next few weeks to test areas closer to water's edge, as well as the band of mud between 10 and 100 feet wide just offshore from the gun club. If lead appears to be a problem, Bartow says excavation or capping the surface could become options.

The scientists also plan to analyze lake water for signs of other problem chemicals such as arsenic, copper and hydrocarbons that have been associated with the gun club.

In East Palo Alto, the PUC got stuck with a big bill for excavation work in wetlands when a gun club that had leased several dozen acres for decades went under in 1994. Since regional water quality control officials ordered a major cleanup, that city's engineers have begun a project whose cost is expected to mount into the millions before it's finished.

The once-depleted Lake Merced has drawn the interest of many groups -- besides the PUC and the Recreation and Park Department -- trying to bring it back in recent years, including the Friends of Lake Merced, the Golden Gate Audubon Society and a group of graduate students at nearby San Francisco State University who've conducted a number of studies. Despite that interest, the response during a recent public comment period on the PUC's Draft Workplan, titled "Lead Shot Characterization and Risk Assessment," has been a little disappointing, according to Barstow.

"We had a total of one comment," he said.