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2 0 1 8 W A T E R Q U A L I T Y R E P O R T 5 1 PA R T P E R T R I L L I O N UNREGULATED SYNTHETIC OR NATURALLY OCCURRING CHEMICALS THAT ARE NOT COMMONLY MONITORED BY WATER UTILITIES ARE KNOWN AS CONTAMINANTS OF EMERGING CONCERN. The Town of Cary is committed to providing high-quality, safe drinking water and closely follows the scientific study of contaminants of emerging concern. More than 100,000 chemicals are registered in the United States, and new chemicals and microorganisms continue to be identified. Some of these contaminants can be detected at extremely low levels (parts per trillion - ppt) by continuously improving test methods. For reference, one ppt is approximately the equivalent of one grain of sugar dissolved in an Olympic-sized swimming pool. The health significance of these trace contaminants is often under review and the subject of further study and research. The fact that a substance is detectable doesn't mean it is immediately harmful. The EPA issues a health advisory for contaminants of emerging concern when research indicates a potential health impact. Health advisories provide information to the public so state and local agencies can take appropriate action to protect public health. The potential health impacts are usually risk-based, where a small amount of a substance, consumed regularly over a long period of time, may increase the risk of certain diseases for some portion of the population. In 2018, as part of a year-long research project investigating treatment improvements, the Town of Cary tested the drinking water for the following contaminants of emerging concern: Per and polyfluoroalkyl substances (PFAS), pharmaceuticals and personal care products (PPCPs) and 1,4-dioxane. PFAS are a class of man-made chemicals used for consumer product applications such as waterproof and stainproof fabrics, nonstick cookware, some food packaging materials and fire suppression foams. In 2018, the Town of Cary tested the drinking water twenty-two times for 39 PFAS compounds. Seven PFAS compounds were detected. The combined concentration of PFOA and PFOS ranged from 0 ppt to 6.3 ppt — which is significantly less than the federally established health advisory of 70 ppt. Pharmaceuticals and personal care products (PPCP) consist of human and veterinary medicine, including hormones, and consumer products such as fragrances, lotions, and sunscreens. The drinking water was monitored two times in 2018 for 94 different PPCP. Five compounds were detected. The EPA has not yet established any health advisories for PPCP in drinking water. 1,4-Dioxane is a colorless, flammable liquid often used as a solvent or solvent stabilizer in the manufacture and processing of polyethylene terephthalate (PET), cotton, textile products, automotive coolant, cosmetics, shampoos and other products. The drinking water was tested for 1,4-dioxane four times in 2018. Results ranged from 0.07 to 0.24, with an average of 0.16 ppb. All results were well below the US EPA's health advisory of 35 ppb. Using the findings from the treatment study, the Town of Cary plans to further improve the water treatment process. Upgrades include changing the filter media from sand and anthracite coal to granular activated carbon as well as converting the existing chemical filtration process to a biological filtration process. These innovative treatment technologies are designed to further reduce contaminants of emerging concern from our drinking water. However, complete elimination of all emerging contaminants is not technologically feasible at this time. EMERGING CONTAMINANTS

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