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The accompanying chart shows the applicable PHG or MCLG and MCL for each <br />contaminant identified above. The chart includes the maximum, minimum, and average <br />concentrations of each contaminant in drinking water supplied by the City in calendar <br />years 2013 through 2015. <br />4.0 Numerical Public Health Risks <br />Section 116470(b)(2) of the Health and Safety Code requires disclosure of the <br />numerical public health risk, determined by OEHHA, associated with the MCLs, Action <br />Levels, PHGs and MCLGs. Available numerical health risks developed by OEHHA for <br />the contaminants identified above are shown on the accompany chart. Only numerical <br />risks associated with cancer- causing chemicals have been quantified by OEHHA. <br />Arsenic — OEHHA has determined that the theoretical health risk associated with the <br />PHG is 1 excess case of cancer in a million people and the risk associated with the <br />MCL is 2.5 excess cases of cancer in 1,000 people exposed over a 70 -year lifetime. <br />Chromium, Hexavalent — OEHHA has determined that the theoretical health risk <br />associated with the PHG is 1 excess case of cancer in a million people and the risk <br />associated with the MCL is 5 excess cases of cancer in 10,000 people exposed over a <br />70 -year lifetime. <br />Coliform Bacteria, Total — USEPA has determined that the health risk associated with <br />the MCLG is 0. <br />Gross Alpha — USEPA has determined that the theoretical health risk associated with <br />the MCLG is 0 and the risk associated with the MCL is 1 excess case of cancer in 1,000 <br />people over a lifetime exposure. <br />Gross Beta — USEPA has determined that the health risk associated with the MCLG is <br />0 and the risk associated with the MCL is 2 excess cases of cancer in 1,000 people <br />over a lifetime exposure. <br />Perchlorate — OEHHA has not established a numerical health risk for perchlorate <br />because PHGs for non - carcinogenic chemicals in drinking water are set at a <br />concentration at which no known or anticipated adverse health risks will occur, with an <br />adequate margin of safety. <br />Uranium — OEHHA has determined that the theoretical health risk associated with the <br />PHG is 1 excess case of cancer in a million people and the risk associated with the <br />MCL is 5 excess cases of cancer in 100,000 people exposed over a 70 -year lifetime. <br />City of Santa Ana <br />Exhibit 1 <br />75C -6 <br />2016 PHG Report <br />