The Quality of Sewanee’s Drinking Water

img_2897The 2014 water crisis in Flint, Michigan brought forth the realization once again that public water supplies were prone to contamination by dangerous chemicals. In the case of Flint, it was elevated levels of lead that caused alarm. Lead is a toxic metal that can build up in the body over time and can severely affect mental and physical development, especially among children (including lower IQ and increased hyperactivity). When Flint changed its water source from Lake Huron to the more corrosive waters of the Flint River, lead began to leach from the aging plumbing system and entered homes where it was consumed and used for bathing and washing. Some homes showed levels at a staggering 13,000 parts per billion (ppb), well above the Environmental Protection Agency’s (EPA) action level of 15 ppb. The shock continued as other communities discovered elevated lead levels in their water supply systems. The state of Maryland found that seven primary and secondary public schools had high levels of lead in their drinking water. Soon municipalities around the country were scrutinizing their water supplies more closely.

Lead in water doesn’t just get there from corroding pipe systems that are made of lead. Many locations around the world have naturally occurring lead in rock, sediment and soil. If groundwater in these areas is the drinking water source, then lead contamination can be expected. Lead mines often lead to groundwater contamination, as was the case in Picher, Oklahoma, which was declared a superfund site by the EPA. Its more than 1500 residents were mostly bought out by the federal government and the municipality has been a ghost town since its last resident died in 2015. Lead contamination from non-water sources, such as old lead paint in houses, may prove to be an even larger threat that water-borne lead.

What about the quality of water in Sewanee? If you are on the Sewanee Utility District’s (SUD) water supply system, then your water comes from our reservoir lakes (O’Donnell and Jackson). This water has either flowed across the ground or leached through the soil and rock into the reservoirs. Happily, the substrate in the area is very low in metals that are of concern in drinking water, including lead. After cleaning and chlorination at the filtration plant the water is sent on its way through pipes to town buildings. The pipes are made of various metals and plastics that could contribute some of their constituent materials to the water. One of my environmental science classes recently had tap water analyzed that was sampled from 24 University buildings (no private homes or businesses were sampled). The results indicate very low concentrations of 59 inorganic elements (metals) commonly found in tap water. Not only were metals well below the maximum allowable levels for drinking water as outlined by the EPA, but some metals of particular concern, like lead, were at such low levels that they could barely be detected.

Iron, which is classified by EPA as a secondary contaminant, can be a nuisance in well and lake water on the Cumberland Plateau, staining laundry and plumbing fixtures pink. It is found at such low levels in our tap water that one would have to drink about 180 liters of it to get the same amount present in a single typical, iron-bearing children’s vitamin. This is the most extensive sampling ever done for inorganic elements in tap water on the campus (note that other contaminants and biological components were not analyzed). The results were shared with the Sewanee Utility District and will contribute to a much more complete picture of Sewanee’s drinking water quality. Bottoms up!


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