Please note, this notice is an update to the previous water notice (dated February 24, 2016) provided by the NY State Department of Health that outlines their more comprehensive assessment of the violation and any impacts. This does not represent a second violation. Nyack Water customers will receive this notice via mail posting.
Nyack Water Department
IMPORTANT INFORMATION ABOUT YOUR DRINKING WATER
Total Trihalomethanes MCL Violation at Nyack Water Department
Our water system recently violated a drinking water standard. Although this is 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. Testing results from the second quarter of 2015 to the first quarter of 2016 show that our system exceeds the standard, or maximum contaminant level (MCL), for total trihalomethanes. The concentration of total trihalomethanes averaged at one of our system’s locations for these four quarters was 82.3 mcg/L. The standard for total trihalomethanes is 80 micrograms per liter (mcg/L or parts per billion). Whether or not the standard is exceeded is determined by averaging all the samples collected at each sampling location for the past 12 months.
What does this mean?
The presence of total trihalomethanes at the concentrations detected in the water system does not constitute an immediate health hazard. The standard is not a “bright line” between trihalomethane concentrations that cause health effects and those that do not. It is set at a water concentration at which exposure is much lower than exposures identified as causing health effects in studies of laboratory animals. Thus, exceedance of the standard is not an indicator for health effects, but an indicator for water suppliers to take action to reduce the trihalomethane concentrations, and maintain what is already a large margin of protection against health effects.
What are trihalomethanes?
Trihalomethanes are a group of chemicals that are formed in drinking water during disinfection when chlorine reacts with 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. They are disinfection byproducts and include the individual chemicals chloroform, bromoform, bromodichloromethane, and chlorodibromomethane. The amount of trihalomethanes formed in drinking water during disinfection 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.
Disinfection of drinking water by chlorination is beneficial to public health. Drinking water is disinfected by public water suppliers to kill bacteria and viruses that could cause serious illnesses, and chlorine is the most commonly used disinfectant in New York State. All public water systems that use chlorine as a disinfectant contain trihalomethanes to some degree.
What are the health effects of trihalomethanes?
Some studies suggest that people who drank water containing trihalomethanes for long periods of time (e.g., 20 to 30 years) have an increased risk of certain health effects. These include an increased risk for cancer and for low birth weights, miscarriages and birth defects. The methods used by these studies could not rule out the role of other factors that could have resulted in the observed increased risks. In addition, other similar studies do not show an increased risk for these health effects. Therefore, the evidence from these studies is not strong enough to conclude that trihalomethanes were a major factor contributing to the observed increased risks for these health effects. Studies of laboratory animals show that some trihalomethanes can cause cancer and adverse reproductive and developmental effects, but at exposures much higher than exposures that could result through normal use of the water. The United States Environmental Protection Agency reviewed the information from the human and animal studies and concluded that while there is no causal link between disinfection byproducts (including trihalomethanes) and human health effects, the balance of the information warranted stronger regulations that limit the amount of trihalomethanes in drinking water, while still allowing for adequate disinfection. The risks for adverse health effects from trihalomethanes in drinking water are small compared to the risks for illness from drinking inadequately disinfected water.
What is being done?
We are working to minimize the formation of total trihalomethanes while ensuring we maintain an adequate level of disinfectant. We are taking steps in an effort to reduce natural organic matter, and thus reduce the precursors of total trihalomethane formation. We will also increase flushing within the distribution system to reduce or avoid one of the mechanisms controlling their formation (water aging). We will be testing again after we initiate these practices to determine if our efforts were successful and following up with further actions as warranted.
What are some other measures people can take?
Some people may wish to take additional practical measures to reduce their exposure. We do not consider these measures necessary to avoid health effects, but they are provided as options. These include using bottled water for drinking and cooking purposes, or using water pitchers containing an activated carbon filter or a tap-mounted activated carbon filter. These filters are readily available in many grocery and home improvement stores. Ventilating bathroom areas (e.g., using exhaust fans or opening windows) when showering or bathing can also help reduce exposures from chemicals released into the air.
Where can I get more information?
For more information, please contact our Water Department Superintendent, Harry Williams at 845-358-3734 or write to Nyack Water Department, 9 North Broadway, Nyack, NY 10960 and/or Rockland County Department of Health at 845-364-2608.
Please share this information with all the other people who drink this water, especially those who may not have received this notice directly. 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 email blast and by US postal service. State Water System ID#: NY4303666.