MEMPHIS, Tenn. (AP) — Memphis residents are as proud of their water as their barbecue and blues.

The Tennessee Valley Authority's coal-burning Allen Fossil Plant on Friday, July 14, 2017 in Memphis, Tenn. Groundwater in wells at the plant have tested for excessive levels of arsenic and lead. AP Photo/Adrian Sainz MEMPHIS, Tenn. (AP) — Memphis residents are as proud of their water as their barbecue and blues.

So alarms went off when state environmental officials and the Tennessee Valley Authority revealed high levels of arsenic and lead had been found in groundwater under the coal-fired Allen Fossil Plant in southwest Memphis.

A layer of clay lies between the groundwater and the aquifer, and the Tennessee Department of Environment and Conservation says it is confident the contaminants are not impacting drinking water. But the state has asked the department has asked Memphis Light, Gas & Water — the city's water utility — to test treated drinking water.

The department has told the TVA, which has a history of problems handling coal ash, that it must determine where the toxins came from. TVA spokesman Scott Brooks says the power company doesn't know the origin of the toxins and is cooperating with the state.