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27 <br /> Health effects —Because coliform is used as an indicator of contamination, a well with persistent <br /> coliform bacteria or with fecal coliform bacteria present should be considered an unsafe source of <br /> drinking water. The presence of coliform indicates that conditions are favorable for the presence of <br /> other bacteria that can cause health problems such as diarrhea, upset stomach, cramps, and vomiting. <br /> Remedial action -When coliform bacteria is present, the well should be chlorinated thoroughly and <br /> retested. If total coliform bacteria return after this treatment, the owner may attempt to repair the <br /> well by installing a liner, or may install a treatment system on the well, typically a chlorinator or <br /> ultraviolet light disinfection unit. If the well exhibits persistent fecal coliform, the well should either <br /> be replaced or repaired with a liner. <br /> Observed incidence of bacteria in wells in Orange County—A sampling of 1500 wells in Orange <br /> County between 2002 and 2006 showed that 32% of the wells had total coliform bacteria and 4% <br /> contained fecal coliform bacteria. <br /> Inorganic Chemical Water Quality <br /> For all 11 wells, the following parameters were tested and were either found within the range of <br /> acceptable drinking water standards, or no drinking water standard exists. <br /> • Arsenic • Fluoride <br /> • Alkalinity • Hardness <br /> • Barium • Magnesium <br /> • Cadmium • Mercury <br /> • Calcium • Selenium <br /> • Chloride • Silver <br /> • Chromium • Sulfate <br /> • Copper • Zinc <br /> The following observations were made regarding other inorganic chemical parameters: <br /> Iron - <br /> Of the 11 wells sampled, four wells exceeded the recommended drinking water limit of 0.30 <br /> milligrams per liter(mg/1). Two of these four wells exceeded the NC public health goal of 2.8 <br /> mg/l. <br /> Iron occurs naturally in groundwater and is the most common source of nuisance problems with well <br /> water in Orange County. While generally not considered a health risk at moderate levels, amounts <br /> of iron above 0.3 mg/1 can cause the water to have a red or brown muddy appearance and can stain <br /> white plumbing fixtures and clothes. <br /> Remedial action - Remedies for those wells with high iron levels include installing a liner in the <br /> well or installing an iron filter or other treatment unit. The liner repair may be an option in limited <br /> cases, depending on the well structure and water bearing zones. <br /> Manganese— <br /> Of the 11 wells sampled, one well exceeded the recommended drinking water limit of 0.05 mg/l. <br /> Page 6 of 11 <br />