In groundwater supply wells, which are typically free of industrial inputs, Cr VI correlates with dichlorodiphenyldichloroethylene DDE , vanadium, and ammonia and clusters with nitrate and dissolved oxygen, suggesting potential links between agricultural activities and Cr VI.
Specific controls on Cr VI vary substantially by region: from the metal plating industry around Los Angeles and the San Francisco Bay areas to natural redox conditions along flow paths in the Mojave Desert and to correlations with agricultural practices in the Central Valley of California.
While industrial uses of Cr lead to the most acute cases of groundwater Cr VI contamination, oxidation of naturally occurring Cr affects a larger area, more wells, and a greater number of people throughout California. Many of these sites are being actively assessed or cleaned-up voluntarily under a State Cost Recovery Program administered by the Regional Board. 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 's through the 's. These chemicals are known human carcinogens.
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.
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. The sampling reports can be accessed. Local and state agencies have worked to identify facilities that produce chromium 6, and to lower the amount of chromium 6 that they release.
The SCAQMD has been developing and implementing new air quality rules to regulate chromium 6 in metal processing facilities. In addition, the City of Paramount has adopted revised zoning rules for metal processing operations to reduce emissions.
DPH and the City of Los Angeles Department of Public works have also collaborated successfully to promote the use of alternative technologies to chromium 6.
A total of 76 event attendees including metal finishers, metal platers, speakers, City staff attended the Symposium and Business Resource Fair. Forty-three metal finishers and platers from both the City and the County attended. The Symposium included presentations on hexavalent chromium alternatives, trivalent chromium and waste reclamation strategies, and technologically advanced wastewater treatment solutions from industry leaders.
Business Visionaries. Hot Property. Times Events. Times Store. Facebook Twitter Show more sharing options Share Close extra sharing options. Employees at the Anaplex Corp. The metal plant is one of two ordered by L. County health officials to stop endangering the health of the public. By Tony Barboza.
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