Pilot - scale studies of Hexavalent Chromium
نویسنده
چکیده
rinking water utilities face the challenge of addressing emerging water quality concerns to ensure adequate protection of public health, sometimes without final federal or state drinking water regulations. Total chromium, i.e., trivalent chromium [Cr(III)] plus hexavalent chromium [Cr(VI)], has been regulated by national drinking water regulations since 1975. The federal regulatory maximum contaminant level (MCL) for total Cr is 100 μg/L, whereas the MCL in California is 50 μg/L. Although no federal limit has been established for Cr(VI) in drinking water, California’s Department of Health Services has a mandate by state law to establish a Cr(VI)-specific MCL. The Cr(VI) carcinogenic de minimis risk level established by the state in 1999 was 0.2 μg/L, which contributed to a public health goal (PHG) of 2.5 μg/L for total Cr (OEHHA, 1999). Although this PHG was later rescinded and is currently under review, the potential for a new MCL for Cr(VI) and a lower California MCL for total Cr provided the impetus to identify treatment technologies able to remove Cr to levels far lower than the current limits. In 2000, public concern about the presence of Cr(VI) in drinking water was stimulated in large part by the movie Erin Brockovich, which highlighted a groundwater Cr pollution lawsuit in Hinkley, Calif. In response to this public concern, the city of Glendale, Calif. with the participation of the California cities of Los Angeles, Burbank, and San Fernando, initiated a four-phase program to D
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