Contaminants

Our objective is to determine the relative propensity of sediment material formed under two different in situ coagulation treatments (iron sulfate, polyaluminum chloride) to release MeHg into surface waters under environmentally relevant conditions that may affect flocculant stability and MeHg production rates.

The objectives of this study are to quantify and characterize (1) phytoplankton production on Liberty Island, (2) utilization and transformation of nutrients, and (3) attenuation/loss of phytoplankton as the material is transported from Liberty Iisland into Cache Slough.

The objective specific to work conducted by the CAWSC is to produce a continuous time-series of suspended-sediment flux at an existing site in Alviso Slough.

The overall project objective is to further our understanding of the link between nitrogen and phytoplankton dynamics in the Sacramento River and to elucidate effects of wastewater treatment plant effluent on food web dynamics.

The Rim Fire has burned over 400 square miles of the Tuolumne River and Merced River watersheds in central California and is now the 3rd largest wildfire in state history. The burn area is largely on the Tuolumne between Hetch Hetchy Reservoir and Don Pedro Reservoir, both of which serve as critical sources of drinking water and irrigation water to San Francisco Bay area and Central Valley...

Pesticides are used throughout the State of California in both urban and agricultural settings and are routinely detected in surface water. Each year, new pesticides are introduced to the market and often become detected in surface water. It can take several years or more for routine monitoring programs to acquire the capability to detect new and understudied pesticides of concern because...

The atmosphere plays an important role in the delivery to and cycling of mercury (Hg) in the environment and it can be a major source of Hg contamination to surface waters. Globally, atmospheric deposition of Hg is the primary source of Hg related concerns for human and ecosystem health (Fitzgerald and others, 1998). In California and other areas in the United States, Hg use in gold and silver...

Extensive mercury use during historical gold processing has resulted in widespread mercury contamination and bioaccumulation of methylmercury in watersheds in the northwestern Sierra Nevada (Slotton and others 1997; Alpers and Hunerlach, 2000). A recent USGS report (May and others, 2000) documented the presence of elevated mercury in fish tissues in five reservoirs in the Bear River, Deer Creek...

Between 1956 and 1972, the Stringfellow Hazardous Waste Site, Riverside County, Calif., discharged approximately 34 million gallons of industrial wastes to unlined surface impoundments located at the head of Pyrite Canyon. Contaminants from the site have been detected as far as 4 miles downgradient near the Santa Ana River. Perchlorate in excess of the California Maximum Contaminant Level of 6...

Dredging to maintain water storage capacity by the Nevada Irrigation District (NID) occurred at Lake Combie reservoir, one of several reservoirs along the Bear River, California over the past 40 years on an as-needed basis to maintain water storage capacity. Maintenance dredging operations were halted by the Central Valley Regional Water Quality Control Board (CVRWQCB) in 2002 because of elevated...

Dredging operations for gold along the American River began in the 1860s and continued through the early part of the 20th century, ending about 1962. More than one billion cubic yards of gravel were dredged, making the American River dredge field the second largest in California.

Pesticides are used in both agricultural and urban settings to manage unwanted plants, insects, fungi, and other pests. However, these substances and their breakdown products can move beyond their intended application sites through various means, ending up in areas where they weren't meant to be. This movement can happen via the air, through water (both surface and groundwater), and by sticking to...