BACKGROUND

The San Fernando Valley (SFV) Basin is an important source of drinking water for the Los Angeles metropolitan area, the cities of Glendale, Burbank, and San Fernando, La Canada- Flintridge, and the unincorporated area of La Crescenta.

In 1998, The Upper Los Angeles River Area (ULARA) Watermaster notified the USEPA and SWRCB that hexavalent chromium was being detected in SFV wells. Since then, an inter-agency committee, the Chromium Task Force, has focused its attention on understanding the nature of the problem. The task force meets quarterly to share information and to keep its members informed of developments regarding hexavalent chromium contamination.

The Regional Board has been charged by the USEPA with the task of locating the sources of hexavalent chromium contamination in the soil and groundwater. If dischargers do not cooperate, the Regional Board and/or USEPA may resort to taking enforcement actions to bring about adequate site characterization. The Regional Board was been awarded a grant from USEPA to address this task during the current fiscal year

THE CHROMIUM PROBLEM

There are two chemical forms of chromium. Chromium compounds have no taste or odor. Trivalent chromium (Cr+3) forms insoluble mineral precipitates and is, in small concentrations, necessary for life as an essential nutrient. Hexavalent chromium (Cr+6), however, forms very soluble, non-reactive compounds in groundwater and is highly toxic to organisms and plants. It is considered carcinogenic. The existence of hexavalent chromium in the environment is associated with industrial waste from metal plating operations, as an example. Chromium is also used when making steel and other alloys, bricks in furnaces, dyes and pigments, chrome plating, leather tanning, and in wood preserving.

Chromium contamination in the soil and groundwater has occurred in the SFV and other areas in southern California. Cr+6 has been detected in production and groundwater monitoring wells in the San Fernando Valley area. Cr+6 has been consistently detected in some shallow and deep monitoring wells primarily in the North Hollywood, Glendale, Burbank and Pollock Operable Units, from depths ranging from 31feet to as deep as 580 feet below ground surface.

Routine sampling of drinking water wells in the San Fernando Valley by the California Department of Health Services (DHS) and the Los Angeles City Department of Water & Power (LACDPW) have discovered elevated levels of Cr+6, also referred to as chromium VI. In the San Fernando Valley, the ratio of total chromium to Cr+6 is between 61% and 100%. No drinking water wells have exceeded the Maximum contaminant level or MCL. The highest value detected in drinking water wells has been 15 µg/L (December 1999). Area-monitoring wells (not used for drinking water supply) for LACDPW have detected total chromium concentrations as high as 97 µg/L (December 1999), while USEPA's monitoring well network has detected Cr+6 as high as 1,000 µg/L (March 2000). Chromium concentrations in groundwater are highly variable depending on how close a monitoring well may be to a potential source of contamination. The Federal Maximum Contaminant Level (MCL) for total chromium in drinking water is 100 micrograms per liter (µg/L). In California, because of the carcinogenic properties of some chromium compounds, a risk-based drinking water standard or MCL has been established for Total Chromium at 50 µg/L (the aggregate of trivalent and hexavalent chromium). There is no MCL established for chromium IV. Generally, the concentrations of chromium in drinking water wells are well below the 50 µg/L. However, in limited areas, the concentrations of chromium close to the source of contamination can be orders of magnitude greater.

THE REGIONAL BOARD'S CHROMIUM INVESTIGATION

The Regional Board has begun to investigate the hexavalent chromium problem in the San Fernando Valley. Regional Board staff has identified over 210-chromium users from a database comprised of 4,040 chlorinated volatile organic compound (VOC) developed under the Regional Board's Superfund investigation (Figure 1). Identification of sites is being coordinated with other agencies including the California Department of Toxics Substances Control (DTSC). In addition, DTSC has identified over 260 suspected chromium users from their Burbank and Glendale databases. The Chromium Investigation Protocol is currently being finalized with USEPA and it is expected that the investigation will formally begin in November 2000. As part of that effort, the Regional Board will be issuing letters to potential contamination sites requiring the completion of an initial questionnaire. Additional action at each site will include detailed inspections and a determination of the need for further assessment, if warranted.

OTHER HEXAVALENT CHROMIUM IMPACTED AREAS

Hexavalent chromium impacted sites exist in other areas of the state, including Daly City, Davis, Brentwood, and Los Banos. In Los Angeles County, the Regional Board is continuing to oversee the assessment and cleanup of hexavalent chromium impacted sites at defense-related businesses, aircraft manufacturing and industrial plating sites. Hexavalent chromium contamination in the soil and groundwater has been found in the cities of Los Angeles, Arcadia, San Marino, Compton, Redondo Beach, Pomona, La Verne, Long Beach, Industry, Hawthorne, and South Gate. Many of these sites are being actively assessed or cleaned-up voluntarily under a State Cost Recovery Program administered by the Regional Board.

THE SUPERFUND INVESTIGATION

THE ORIGINAL PROBLEM - SOLVENTS

The primary contaminants of concern in the groundwater were the volatile organic compounds (VOCs) trichloroethylene (TCE) and perchloroethylene (PCE). In addition, the soil was investigated for the presence of these organic solvents and heavy metals such as lead, chromium, nickel and cadmium. This combination of solvents and heavy metals was widely used in a variety of industries including aerospace component manufacturing, metal plating, machinery degreasing, and dry cleaning. Most of the industries targeted were affiliated with the nation's defense industry that boomed in the area in the 1940's through the 1970's.

Concentrations of TCE and PCE were detected in a large number of production wells at levels that are above the Federal Maximum Contaminant Level (MCL) drinking water standards, which is 5 parts per billion (ppb) for each of these VOCs. The State of California MCL is also 5 ppb for TCE and PCE. These chemicals are known human carcinogens. Other contaminants, like nitrates, have also been detected above the Federal and/or State MCLs in the San Fernando Valley.

As a result of the groundwater contamination, as many as 20 production wells were taken out of service. The water agencies in the San Fernando Valley area closely monitor the quality of drinking water delivered to residents. The water meets all federal and state requirements and is safe to drink, as determined by DHS. In part due to groundwater contamination, much of the drinking water delivered to residents is purchased from the Metropolitan Water District (MWD) of Southern California.

IMPLEMENTING A SUPERFUND SOLUTION

State and local agencies acted to provide alternative water supplies and to investigate and clean up potential sources. USEPA, and other agencies, became involved in coordinating efforts to address the large-scale contamination. In 1984, EPA proposed four sites for inclusion on the Superfund National Priorities List (NPL) under the Comprehensive Environmental Response Compensation and Liability Act (CERCLA): North Hollywood, Crystal Springs, Pollock, and Verdugo. These areas were later subdivided into six operable units: North Hollywood, Burbank, Headworks, Glendale-North, Glendale-South, and Pollock (Figure 2). The original boundaries of the sites were based on drinking water wellfields that were contaminated by VOCs in 1984. In 1986, the four sites were included on the NPL. USEPA manages the four sites and adjacent areas where contamination has (or may have) migrated as one large site estimated at about 18 square miles. USEPA's groundwater solution for the San Fernando Valley involved water treatment of the VOC plume was estimated to cost $180 million over 20 years processing impacted water at a rate of 9,000 gallons per minute (gpm).

In 1987, EPA and Los Angeles Department of Water and Power (LADWP) signed a Cooperative Agreement providing federal funds to perform a remedial investigation (RI) of groundwater contamination in the San Fernando Valley. USEPA is coordinating the large-scale effort for groundwater monitoring and the basinwide groundwater feasibility study (FS).

The Los Angeles Regional Water Quality Control Board has entered into a cooperative agreement with USEPA to conduct site assessments, assisting with the identification of potentially responsible parties (PRPs), reviewing groundwater monitoring reports, directing cleanup, and issuing enforcement orders. The intent is to ensure that progress continues to be made within the six Superfund Operable Units in the San Fernando Valley. There are 4,040 cases in the SFV Superfund database.