Frequently Asked Questions Regarding Your Disinfection Byproduct Notice:
The City of Burlington was recently required to provide its water customers with a notification regarding a violation of a drinking water standard. These notices were sent out with monthly water bills and hand delivered to apartment complexes for those residents who do not receive a water bill directly from the City.
These notices were concerning an exceedance of the Stage 2 Haloacetic Acid (HAA) standard for Drinking Water.
This is the third consecutive quarter that the HAA limits have been exceeded for the Burlington Water System.
Water Resources Staff put together this page to help explain the causes of these recent violations as well as to answer some of the questions that water customers may have regarding this issue. If the information contained here does not adequately address your questions or concerns, please feel free to contact the Water Resources staff at (336) 222-5133 or to contact staff at the NC Department of Environment and Natural Resources at (336) 771-5080.
FAQ-1: What are the Risks to Public Water System Customers from Disinfection Byproducts?
Answer-1: Trihalomethanes (THMs) and Haloacetic acids (HAAs) form when disinfectants are added to drinking water systems to kill potentially dangerous microorganisms. The added disinfectants react with naturally occurring organic chemicals in the water to form other chemicals, including THMs and HAAs. Because long-term exposures to these chemicals in our water may result in adverse health effects, EPA has established standards (the MCLs) for them. When they exceed their respective MCLs in drinking water, your provider is required to notify you. Notification is not intended to suggest that you or your family members will be harmed by the detected levels, but instead is meant to keep you informed. Exceedance of MCLs also informs the water supplier that action is warranted to reduce the concentrations of those chemicals in the water system.
The required public notice language for these violations includes statements like:
• This is not an emergency.
• You do not need to use an alternative water supply.
• Some people who drink water containing these chemicals in excess of the MCL over many years may have an increased risk of cancer (HAA and THM) or some other long-term health effect (THM only).
When EPA establishes the MCL for a chemical that is known or suspected to cause adverse health effects from long-term exposures, it assumes that the people who drink that water consume two liters (about half a gallon) of it every day for seventy years (approximately one lifetime). MCLs also are set at levels that are expected to protect susceptible groups in our population, for example, children, pregnant women, the elderly, and people who may have existing health problems. For chemicals that may cause cancer, EPA also considers what amount of the chemical would cause an increased risk of one (1) case in one million (1,000,000) people who are exposed over their lifetime.
It is unlikely that the short amount of time (relative to seventy years) that customers will drink the water with high THMs and HAAs should cause any adverse effect on their health. EPA has identified THMs and HAAs as a long-term health risk, not a short-term health risk. It would be much more risky to drink water that did not have enough chlorine than to drink water that has high levels of disinfection byproduct.
There is no imminent risk to the health of customers.
FAQ-2: What is an HAA
Answer-2: HAA is an abbreviation for Haloacetic Acid. Haloacetic Acids are one of the regulated classes of Disinfection By-Products, often referred to as DBPs. There are 5 compounds that make up the regulated HAAs. The sum total of all five of these HAA’s is used in the compliance calculation for drinking water.
FAQ-3: What are disinfection byproducts (DBPs)?
Answer-3: Chlorine disinfection of drinking water is one of the major public health advances in the 20th century. One hundred years ago, typhoid and cholera epidemics were common through American cities; disinfection was a major factor in reducing these epidemics. Unfortunately, disinfectants can react with naturally occurring materials in the water to form disinfection byproducts (DBPs), which may pose health risks. The specific DBP regulations that are discussed here are for two DBP families: trihalomethanes (THMs) and haloacetic acids (HAAs).
FAQ-4: What is the history of DBP regulation?
Answer-4: In November 1979, EPA set an interim maximum contaminant level (MCL) for total THMs of 0.10 milligrams per liter (mg/L) as an annual average for community public water systems (PWSs) serving 10,000 or more people. The Stage 1 Disinfectants and Disinfection Byproducts Rule (DBP1) was promulgated in December 1998 as the first phase in a rulemaking strategy required by Congress as part of the 1996 Amendments to the Safe Drinking Water Act. DBP1 lowered the MCL for THMs to 0.080 mg/L, and added an MCL for HAAs of 0.060 mg/L, both based on an annual average. The Stage 2 Disinfectants and Disinfection Byproducts Rule (DBP2) of December 2005 builds upon the DBP1 to address higher risk public water systems for protection measures beyond those required for existing regulations.
FAQ-5: What are the requirements of DBP2?
Answer-5: Under the Stage 1 DBP Rule (DBP1), water system compliance was based on the annual average of THMs and HAAs. Since higher levels of THMs and HAAs are found in the warmer months of the year, it was necessary to look at a systems performance over a 12-month period to assess compliance.
The DBP2 rule required water systems to determine the sample sites in their distribution system with the highest risk for DBPs and then take compliance samples at those locations. The idea is that if the worst case sites in a water system are below the standard, then it is safe to assume that the rest of the sites in a system are also below the limits.
Secondly, the DBP2 rule required that compliance calculation look at each sample site individually. This is called the Locational Running Annual Average, or LRAA. Instead of averaging all 8 sample sites together every quarter and reporting a single value to the State – which was the rule under the DBP1 rule, water systems are required to report the running annual average for each site individually. This means that water systems now have to be in compliance at all 8 sites each year rather than averaging the 8 sample results together to get a system average.
FAQ-6: What are the benefits of the rule?
Answer-6: Quantified benefits estimates for DBP2 are based on reductions in fatal and nonfatal bladder cancer cases. EPA has projected that the rule will prevent approximately 280 bladder cancer cases per year in the United States. Of these cases, 26 percent are estimated to be fatal. Based on bladder cancer alone, the rule is estimated to provide annual monetized benefit of approximately $763 million to $1.5 billion savings.
FAQ-7: How many sites in Burlington are affected by this violation?
Answer-7: There are eight (8) sample locations around the City that are used as DBP2 compliance sites. Six (6) of these sites represent “worst case” sites for Disinfection Byproducts and two (2) were selected from among the eight DBP1 sample locations. AS of October 2013, only 1 of the 8 sample locations is above the regulatory limit for HAA. The annual average for this site was 65 ppm of HAA – slightly above the regulatory limit of 60 ppm.
FAQ-8: What is the City of Burlington doing to correct this issue?
Answer-8: The Water Resources Staff has been working to identify the cause of this violation and incorporate a treatment strategy to reduce the levels of DBP in the water system. Colder weather and colder water will help reduce the formation of these DBPs and the addition of ammonia as part of the treatment process will help slow the formation of these byproducts. In addition, the use of certain treatment chemicals during certain times of the year has demonstrated some promise of reducing these DBPs and returning the City water system back into compliance.
FAQ-9: Who can I call if I have other questions?
Answer-9: You can reach the Water Resources Staff by calling (336) 222-5133 on weekdays between the hours of 7:30 AM and 5:00 PM. Just let us know that you have a question regarding the Disinfection Byproduct notice and you will be connected to the appropriate person.