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9.A. - Page 17 <br /> oteo a`$(.4 riosr, Final Public Health Goal for <br /> Hexavalent Chromium <br /> A fact sheet by the Office of Environmental Health Hazard <br /> • OEHHA <br /> • Assessment, California Environmental Protection Agency <br /> O 44a <br /> �s�A4B <br /> p4, CAtrFo,s0' s <br /> *'41 AROTE July 2011 <br /> Q. What is a Public Health Goal (PHG)? <br /> A. A Public Health Goal or PHG is a level of a contaminant in drinking water that does not <br /> pose a significant health risk. <br /> A PHG is not a regulatory standard. It is only one step in the process of developing an <br /> enforceable standard that is set by the California Department of Public Health for drinking <br /> water that public water systems must meet. <br /> State law requires OEHHA to develop PHGs for regulated drinking water contaminants. The <br /> PHG for chromium 6 is 0.02 parts per billion (ppb), which is the estimated "one in one <br /> million" lifetime cancer risk level. This means that for every million people who drink two <br /> liters of water with that level of chromium 6 daily for 70 years, no more than one person <br /> would be expected to develop cancer from exposure to chromium 6. The "one-in-one million" <br /> risk level is widely accepted by doctors and scientists as the "negligible risk" standard. <br /> A PHG reflects the risk from long-term exposure to a contaminant and should not be used to <br /> estimate risks from short-term or acute exposure. <br /> Q. What is hexavalent chromium? <br /> A. Hexavalent chromium, also known as chromium 6, is a heavy metal that is commonly <br /> found at low levels in drinking water. It can occur naturally but can also enter drinking water <br /> sources by historic leaks from industrial plants' hazardous waste sites. Various other <br /> sources also contribute to the amount of hexavalent chromium in groundwater. Chromium 6 <br /> is known to be a potent carcinogen when inhaled. It was recently found to also cause cancer <br /> in laboratory mice and rats that were exposed through drinking water. <br /> Q. What is the difference between chromium 6 and chromium 3? <br /> A. Chromium is found in drinking water sources and the environment in two principal forms: <br /> trivalent chromium (chromium 3) and hexavalent chromium (chromium 6). Chromium 3 is <br /> found naturally in foods at low levels and is an essential human dietary nutrient. Chromium <br /> 6 is the more toxic form of chromium. <br /> Chromium can transform from its hexavalent form to its trivalent form, and vice versa. When <br /> an industrial facility emits chromium 6 into the environment, it is sometimes deposited into <br /> the soil and often is converted to chromium 3 with some remaining traces of chromium 6. <br />