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9.A. - Page 18 Page 2 of 3 <br /> OEHHA's PHG focuses on hexavalent chromium, not trivalent chromium. <br /> Q. How is chromium used? <br /> A. Chromium is used in many products and processes, including stainless steel, textile dyes, <br /> wood preservation, leather tanning, and anti-corrosion coatings. Chromium coatings are <br /> applied to aluminum, zinc, cadmium, copper, silver, magnesium and tin to prevent rust or <br /> other damage that can occur from exposure to oxygen. <br /> Q. How is a PHG used? <br /> A. The California Department of Public Health (CDPH), which regulates public drinking <br /> water suppliers, uses PHGs to set California's regulatory drinking water standards, officially <br /> known as Maximum Contaminant Levels (MCLs). State law requires CDPH to set each MCL <br /> as close to the corresponding PHG as is economically and technically feasible, and to place <br /> primary emphasis on the protection of public health. <br /> CDPH can set the MCL above the level of the PHG if it finds that it is not economically or <br /> technically feasible to reduce the contaminant to the PHG level. State law prohibits OEHHA <br /> from considering economic issues when it develops a PHG. <br /> An MCL is an enforceable standard. This means that when an MCL is established for a <br /> specific contaminant, the level of that contaminant in public drinking water systems must not <br /> exceed the MCL. The PHG is not an enforceable standard. <br /> Q. How is a PHG established? <br /> A. The process for establishing a PHG is detailed and rigorous. OEHHA scientists first <br /> compile all relevant scientific information available. This includes studies of the chemical's <br /> effect on laboratory animals and studies of humans who were exposed to the chemical. The <br /> scientists use the data from these studies to perform a health risk assessment that <br /> determines the levels of the contaminant in drinking water that could be associated with <br /> various adverse health effects. <br /> OEHHA must consider many factors in the health risk assessment. They include impacts on <br /> certain groups of people, such as pregnant women, young children, the elderly or persons <br /> with pre-existing illnesses. These groups may be especially susceptible to the chemical's <br /> adverse effects. <br /> To calculate a PHG, OEHHA uses this information to identify the level of the chemical in <br /> drinking water that would not cause significant adverse health effects in people who drink <br /> that water every day for 70 years. OEHHA assumes that an adult will drink two liters of water <br /> per day. OEHHA must also consider any evidence of immediate and severe health effects. <br /> It establishes the PHG at a level that provides protection against any known cancer and <br /> "non-cancer" health effects associated with exposure to the chemical. <br /> For more information on PHGs, please visit <br /> http://www.oehha.ca.gov/water/phg/pdf/PHGfacts.pdf. <br />