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The EPA started a short-term cleanup in fall of 2011, removing 233 drums of industrial waste and 6,100 gallons of chromium-contaminated water from the site. From 2012 through 2014, the EPA demolished the E.C Electroplating building, and contaminated soils and concrete from the site were excavated and removed.
Hexavalent chromium (chromium(VI), Cr(VI), chromium 6) is any chemical compound that contains the element chromium in the +6 oxidation state (thus hexavalent). [1] It has been identified as carcinogenic, which is of concern since approximately 136,000 tonnes (150,000 tons) of hexavalent chromium were produced in 1985. [ 2 ]
California was the first state to put into effect an MCL for hexavalent chromium (chromium 6) in drinking water in July 2014, setting a limit of 10 ppb. A 2015 United States Geological Survey (USGS) report, based on the EPA's 2010 review of the health effects of chromium 6 in drinking water, re-examined related federal regulations.
Hexavalent chromium is used in chrome plating, chromate coatings and primers, and in chromic acid. The maximum permitted concentrations in non-exempt products are 0.1% or 1000 ppm (except for cadmium, which is limited to 0.01% or 100 ppm) by weight.
The contamination resulted in a $333 million settlement in 1996. The clean-up process is ongoing as of 2022, with monthly monitoring reports submitted by PG&E. [69] This case has led to California being the only state in the US to adopt an MCL of 10 ppb specifically for hexavalent chromium instead of relying on an overall total chromium count. [70]
The EPA has been successful in restricting five chemicals using section 6 authority (PCBs, chlorofluorocarbons, dioxin, asbestos, and hexavalent chromium) in its 38-year history, [39] with the ban on asbestos being partially overturned in 1991. [40] EPA has restricting some existing chemicals using Section 5 SNURs. [41] [42]
The EPA and companies responsible for the waste in this area, which includes a three-mile section of Portage Creek as well as part of the Kalamazoo River, into which it flows, are currently involved in an effort to reduce the amount of toxic waste at the site, which is contaminated by PCBs (polychlorinated biphenyls) from paper mills and other ...
Chromium compounds are compounds containing the element chromium (Cr). Chromium is a member of group 6 of the transition metals. The +3 and +6 states occur most commonly within chromium compounds, followed by +2; charges of +1, +4 and +5 for chromium are rare, but do nevertheless occasionally exist. [3] [4]