Contaminants

The effect of selenium toxicity on wildlife has been known for more than 50 years. This issue drew particular attention in the 1980s when embryo deformity and mortality was observed in birds at a wildlife refuge in California. Harmful effects from selenium were determined to be connected to irrigation drainage water. As a result, an effort began to monitor levels of selenium in irrigation drainage...

John Izbicki, PhD, a Research Hydrologist with the U.S. Geological Survey (USGS) California Water Science Center (CAWSC), led a five-year scientific study to determine the range of natural and anthropogenic (human-caused) hexavalent chromium concentrations, also referred to as chromium-6 or Cr(VI), in Hinkley Valley. The study was cooperatively funded by the Lahontan Regional Water Quality Control...

Keswick Reservoir, on the Sacramento River, receives both water and contaminants from the Spring Creek Debris Dam. The term contaminants refers here to different kinds of chemicals that are in some instances delivered to lakes and rivers. These chemicals can have a detrimental effect on drinking water supplies and the health of humans, fish, and other aquatic species.

The Biogeochemistry (BGC) Group uses an interdisciplinary approach to address surface water quality issues and food web dynamics throughout California, particularly in the Sacramento-San Joaquin Delta and San Francisco Bay.

Mercury (Hg) is a contaminant of significant concern in the San Francisco Bay-Delta estuary and watershed (Bay-Delta). The formation, fate, and transport of methylmercury (MeHg), a particularly toxic organic form of Hg that readily bioaccumulates in wildlife, has been studied extensively throughout the system. However, there is widespread recognition of the need for more comprehensive monitoring...

The abandoned Sulphur Bank Mercury Mine on the shores of Clear Lake in Northern California has been designated as a "Superfund Site" by the U.S. Environmental Protection Agency (EPA). This means that the EPA has determined that the area is contaminated by hazardous waste and requires cleanup because it poses a risk to human health and/or the environment. One of the chief contaminants at the site...

Located in Nevada County, California, Malakoff Diggins State Historic Park was the Sierra Nevada’s largest hydraulic gold mine, operating from 1866 to 1884. Historically, part of the process of hydraulic mining included using mercury to extract gold from produced sediment through the process of amalgamation. This process left thousands of pounds of mercury and other heavy metals in the area...

Better understanding of mineral deposits and their impact on the environment, including the water system, is necessary for the protection of public health. The USGS is working with other federal and state agencies to identify the environmental behavior of these deposits and their waste products. USGS scientists are using geospatial data (data that can be mapped) to prioritize abandoned mine land...

Suisun Bay is an area identified as critical habitat for the threatened Delta Smelt. Several important changes in the pelagic food web of this area have been documented over the last two decades indicating that food for Delta Smelt and other threatened fishes is in short.

At two priority locations on BLM-administered land in the Yuba River watershed, the USGS has documented relatively rapid erosion of river bank material that consists of mercury (Hg)-laden sediment with a significant component of mining debris.

The California Department of Pesticide Regulation (DPR) has been monitoring pesticide concentrations in about 70 domestic drinking water wells located in vulnerable areas of Fresno and Tulare Counties for approximately 15 years. A recent analysis of the monitoring data indicated that there were decreases in simazine, diuron, and bromacil concentrations in many wells during 2000-2010.

The Leviathan Mine, located in Alpine County is one of the worst sites in California for acid mine drainage. The site is on the National Priority List for CERCLA (Superfund) (U.S. EPA, 2011) and U.S. EPA is working with ARCO/BP (the Responsible Party) on designing and implementing site remediation. The USGS did research there during the 1980s on geochemistry (e.g., Nordstrom and Ball, 1986). The...