IMPORTANT INFORMATION ABOUT YOUR DRINKING WATER
Mohawk Valley Water Authority – NY3202411
Elevated Trihalomethane Levels Detected in Mohawk Valley Water Authority
This is an alert about your drinking water. The Mohawk Valley Water Authority (MVWA) is in violation of
the Maximum Contaminant Level (MCL) for Total Trihalomethanes (TTHMs).
MVWA monitors eight (8) sites quarterly for TTHM. One site located near the former Oneida County Airport in Oriskany exceeded
the MCL. The limit is 80 parts per billion (ppb) and the value was 81ppb in May and 83ppb in August. All other areas remain
in compliance. MVWA has taken several short- and long-term proactive measures to lower TTHM in the area including,
- Extensive flushing in the area to decrease water age, a major contributor to elevated TTHM levels.
- Carefully lowering the chlorine residual level in the system to decrease TTHM formation.
- Changing our granular activated carbon (GAC) replacement strategy to maximize organics removal at the water treatment plant.
- Evaluating different types of GAC used at the water treatment plant.
Trihalomethanes are a group of chemicals that includes chloroform, bromoform, bromodichloromethane, and chlorodibromomethane.
Trihalomethanes are formed in drinking water during treatment by chlorine, which reacts with certain acids that are in
naturally occurring organic material (e.g., decomposing vegetation such as tree leaves, algae, or other aquatic plants)
in surface water sources such as rivers and lakes. The amount of trihalomethanes in drinking water can change from day to day,
depending on the temperature, the amount of organic material in the water, the amount of chlorine added, and a variety of
other factors. Drinking water is disinfected by public water suppliers to kill bacteria and viruses that could cause
serious illnesses. Chlorine is the most commonly used disinfectant in New York State. For this reason, disinfection of
drinking water by chlorination is beneficial to public health.
Some studies suggest that people who drink chlorinated water (which contains trihalomethanes) or water containing elevated
levels of trihalomethanes for long periods of time may have an increased risk for certain health effects. For example,
some studies of people who drank chlorinated drinking water for 20 to 30 years show that long term exposure to disinfection
by-products (including trihalomethanes) is associated with an increased risk for certain types of cancer. A few studies of
women who drank water containing trihalomethanes during pregnancy show an association between exposure to elevated levels
of trihalomethanes and small increased risks for low birth weights, miscarriages and birth defects. However, in each of the
studies, how long and how frequently people actually drank the water, as well as how much trihalomethanes the water
contained is not known for certain. Therefore, we do not know for sure if the observed increases in risk for cancer and
other health effects are due to trihalomethanes or some other factor. The individual trihalomethanes chloroform,
bromodichloromethane and dibromochloromethane cause cancer in laboratory animals exposed to high levels over their lifetimes.
Chloroform, bromodichloromethane and dibromochloromethane are also known to cause effects in laboratory animals after high
levels of exposure, primarily on the liver, kidney, nervous system and on their ability to bear healthy offspring. Chemicals
that cause adverse health effects in laboratory animals after high levels of exposure may pose a risk for adverse health
effects in humans exposed to lower levels over long periods of time.
We will keep you informed regularly regarding the status of our sampling and any changes to the quality of our water.
For more information, please contact Mohawk Valley Water Authority at (315) 792-0338.