ARNOLD AIR FORCE BASE, Tenn. -- Our water system, at Arnold Air Force Base, recently violated a drinking water standard. Although this incident was not an emergency, as our customers, you have a right to know what happened and what we are doing to correct this situation.
We routinely monitor for the presence of drinking water contaminants. During the April 1, 2020 through March 31, 2021 compliance period, the water system’s Locational Running Annual Average (LRAA) at site #201, (Arnold AFB Commissary; bldg. 125) and site #202, (Aeropropulsion Systems Test Facility Test Support; bldg. 1099) for Total Trihalomethanes (TTHMs) has been calculated to be 0.083 mg/L and 0.087 mg/L respectively. This value exceeds the maximum contaminant level of 0.080 mg/L set for TTHMs.
What should I do?
There is nothing you need to do. You do not need to boil your water or take other corrective actions. If a situation arises where the water is no longer safe to drink, you will be notified within 24 hours.
If you have a severely compromised immune system, have an infant, are pregnant, or are elderly, you may be at increased risk and should seek advice from your health care providers about drinking this water.
What does this mean?
This is not an emergency. If it had been an emergency, you would have been notified within 24 hours.
Total Trihalomethanes are four volatile organic chemicals which form when disinfectants react with natural organic matter in the water. Disinfectants are used to minimize the risk of microbial contaminants in drinking water. The Environmental Protection Agency considers microbial contaminants as the greatest risk to the public.
People who drink water containing trihalomethanes in excess of the MCL over many years may experience problems with their liver, kidneys, or central nervous system, and may have an increased risk of getting cancer.
What is being done?
TTHM levels during the second quarter of 2020 were high due to a chlorine dioxide generator (water treatment method) malfunction causing the treatment plant to shut it down for repair. This occurred during the same period the TTHM samples were collected which is not representative of a fully functional system. This equipment has been fixed and this issue is resolved.
The TTHM levels for the fourth quarter were exceeded due to an incorrect ratio of chlorine to sodium chlorite feeding the chlorine dioxide generator. The chlorine feed was too high helping to contribute to the production of TTHM. The ratio was corrected Nov. 24, 2020. Non-regulatory samples that have been taken since Nov. 24 have confirmed that the corrections made to the chlorine dioxide generator has reduced the TTHM levels both at the plant and in the distribution system. AEDC will continue to monitor and maximize the operation of the chlorine dioxide generator.
For more information, call 931-454-6232.
Please share this information with all the other people who drink this water, especially those who may not have received this notice directly (for example, people in apartments, nursing homes, schools, and businesses). You can do this by posting this notice in a public place or distributing copies by hand or mail.
This notice is being sent to you by the AEDC Main Base Complex water system, PWSID #TN0004408.
Date distributed: March 20, 2021.