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Health effects -Because coliform is used as an indicator of contamination, a well with persistent 18 <br />coliform bacteria or with fecal coliform present should be considered an unsafe source of drinking <br />water. The presence of coliform indicates that conditions are favorable for the presence of other <br />bacteria that can cause health problems such as diarrhea, upset stomach, cramps, and vomiting. <br />Remedial action -When coliform is present, the well should be chlorinated thoroughly and retested. <br />If total coliform bacteria return after this treatment, the owner can opt to either attempt to repair the <br />well by installing a liner, or to 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 <br />• Alkalinity <br />• Barium <br />• Cadmium <br />• Calcium <br />• Chloride <br />• Chromium <br />• Copper <br />• Fluoride <br />• Hardness <br />• Magnesium <br />• Mercury <br />• Selenium <br />• Silver <br />• Sulfate <br />• 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 />mg/l. Two of these four wells exceeded the NC public health goal of 2.8 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 not considered a health risk, levels of iron above 0.3 mg/1 can cause <br />the water to have a red or brown muddy appearance and can stain white plumbing fixtures and <br />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 />