Editor's note: This is the first in a two-part story, originally published in UC Davis Magazine, about Clear Lake and the research that UC Davis scientists are conducting at the Superfund site. By Susanne Rockwell Herman Pit, from a distance a deceptively pretty pond, was once an open-pit mercury mine. The land around the pond is mostly bare, with thin tufts of summer-dried grass growing in patches on mounds and depressions of orange-tinged rubble, composed of iron, aluminum, sulfur, silica and other minerals found in this volcanic region 120 miles north of San Francisco in the Coast Range. Various pieces of testing equipment-trays floating in the pond to measure evaporation rates and devices for measuring water levels-stud the site. Large corrugated black pipes connect the pit to Clear Lake to prevent rainy-season overflow from sweeping over the dam of waste rock. On a little test plot, a handful of scrub oaks and native grasses thrive in soil heavily amended with compost from Petaluma and a lime byproduct from a Woodland sugar beet factory. Known as Sulphur Bank Mercury Mine, the property was designated a Superfund site in 1991 and is one of more than 1,200 such hazardous waste areas in the United States that the federal government is currently studying or in the process of cleaning up. For the past seven years, Tom Suchanek, a research scientist with the UC Davis Department of Wildlife, Fish and Conservation Biology and director of the Clear Lake Environmental Research Center, has headed a Superfund team of three dozen scientists and graduate students from campus. Using federal Environmental Protection Agency funding of about $500,000 a year, they have been studying this former open-pit mine and its relationship to the high levels of mercury in certain Clear Lake fish. In the process, Suchanek and his team have conducted what has turned out to be the largest Superfund mercury-mining investigation in the country. "You need interdisciplinary studies to find answers," Suchanek maintains. For the Clear Lake project, he gathered ecologists, engineers, microbiologists, wildlife conservationists, chemists, geochemists, soil scientists and geologists. This kind of research takes not only in-depth expertise but scientists willing to cross disciplines to communicate with others. Suchanek fostered a process of regular daylong symposiums along with other opportunities for participants to debate interpretations via long-sometime fractious-discussions. It's been a process of hashing out opposing hypotheses and connecting the dots between hitherto discrete disciplines to create those exhilarating "ah ha!"s of discovery. From seven years of eliminated hypotheses, serendipitous discoveries, and huge quantities of measurements and statistics leading to stacks of research findings, a whole picture of the mercury contamination has begun to emerge in the past year. That picture confirms the initial suspicion -- that the mine site is, indeed, a primary source of mercury for Clear Lake -- but also includes a host of surprises. "This is a monster project that started out as an attempt to solve the problem of acid-mine discharge into the water with a 'we've got to do something about this' approach," explains Jeff Mount, former chair of the geology department at UC Davis. "But it's become a classic example of the future of environmental research." Adding to campus reputation As the geologists, chemists, engineers, ecotoxicologists, biologists and conservationists make their discoveries at Clear Lake, they are adding to UC Davis' already dominant strength in the state as an environmental campus with a particular expertise in water research. For California, where "save the environment" is often a code phrase for "clean up the water," the Clear Lake studies have the potential to provide a number of answers to questions about how water becomes tainted. That problem certainly has caught the attention of state voters, who in 1996 approved nearly $1 billion in bonds to ensure safe drinking water and increase water supplies, as well as to clean up pollution in rivers, lakes, bays and coastal areas. Since then, Proposition 204 has been funding a number of studies, many involving UC Davis scientists, through a powerful 5-year-old confederation of 11 state and federal agencies called CALFED. Most recently, the confederation has been funding research that focuses on the impact of metal-rich fluids from these old mining sites that, even many decades after the mines have closed, are washing contaminants and mud into the Sierra, Cascade and Coast ranges' watersheds and out into San Francisco Bay. "There's such a large amount of sediment still moving down," explains Rob Zierenberg, formerly of the U.S. Geological Survey and now a geochemist in the UC Davis Department of Geology. "The Gold Rush permanently changed the whole San Francisco Bay," he said, noting that the San Pablo Bay mud flats were created as a result of the hydraulic mining. Mine started for gunpowder makers Sulphur Bank Mercury Mine's operation began promisingly enough. Settlers on the Oaks Arm of the lake in 1862 noticed a sulfur deposit in an area with geothermal springs. They began mining the pale-yellow non-metallic substance for sale to gunpowder makers. Within a few years, the settlers discovered the sulfur was contaminated with cinnabar -- an ore that contains mercury, which when extracted into a liquid becomes quicksilver. Mercury, by this time, was essential to efficient gold mining. Miners had discovered that they could extract gold by adding quicksilver to crushed ore to create a gold/mercury alloy. They would then heat the alloy, vaporizing the mercury and leaving the pure gold. Although the mercury was valuable and miners recycled it, much was lost in the environment through inefficient vaporizing/condensation processes. The gold mining demand for mercury during the late 19th century helped spur mercury mine development -- more than 300 abandoned mercury mines and prospects can now be found along the California Coast Range. To meet the demand, the Sulphur Bank Mercury Mine owners in 1872 began sending Chinese workers down holes 50 to 60 feet deep to extract cinnabar. The mine owners escalated their excavation in 1882 by constructing mine shafts into the ground 200 feet or more deep. Since the lakeshore area was also a geothermal site, the deeper mines were hot -- as high as 120 degrees Fahrenheit at the bottom of the shafts. Laborers could spend only a little time below before being hauled up and cooled down with hoses-and then lowered again to dig more ore. Other mine workers were stationed at sites scattered above the mine, processing mercury from the ore by cooking the rocks in "retorts," or mining ovens. The ovens evaporated the mercury, which then was converted by distilling it back to the more-stable liquid quicksilver. Trails of calcines and waste rock that contain low levels of mercury still scar the hills above the barbed-wire fence that encloses the Superfund site. The shafts gave way to an open pit when gas-driven steam shovels, bulldozers and dump trucks were developed in the late 1920s. This method is believed to have caused a major increase in the amount of mercury-contaminated sediment going into Clear Lake beginning in 1927. Suchanek has found sediment cores from the lake bottom show a corresponding increase in mercury. That heightened mercury level continues in the lake today. By the time the mine was closed in 1957, more than 4,000 tons of pure mercury had been extracted. What remained was a hole 90 feet deep that began to fill with water from geothermal springs and creeks running through the property. The surrounding environment was left barren except for waste rock-laced with low levels of pyrites and mercury. The waterhole, now dubbed Herman Pit, is sparkling clear because nothing besides bacteria can live in this highly acidic pool, Suchanek points out. The pit, in fact, measures a quite-acidic pH 3, in contrast to the lake's just slightly alkaline pH 8. According to geochemist Zierenberg, the acidity can be traced to a mineral called pyrite, or iron sulfide, which is common in rocks in the area. Pyrite, when exposed to oxygen-whether in the air or in water-creates sulfuric acid. The sulfuric acid, in turn, dissolves metals in the site's rocky and churned-up ground. These metallic fluids-filled with aluminum, zinc, arsenic, copper and, of course, mercury-make up the acid mine drainage. Next week: What the UC Davis research scientists found when they studied the effects of mercury on Clear Lake.