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Health Indicator Report of Community Water: Haloacetic Acids (Five) (HAA5) Concentration - Disinfection Byproducts

Disinfection byproducts (DBP) are formed when disinfectants, such as chlorine are used in a water treatment to inactivate (or kill) pathogens (i.e., disease causing organisms) present in the source of water (i.e., lake, river, reservoir, or ground water aquifer). Different disinfectants produce different types and amounts of DBPs that may be harmful to human health. Therefore, the Environmental Protection Agency (EPA) developed requirements or regulations for water treatment that would both protect people from waterborne pathogens and related diseases and the potential harmful effects of DBPs. Most common DBPs are produced when chlorine reacts with natural organic matter (e.g., decaying vegetation) present in the source water. Water in which DBPs are present is a very complex mixture. Formation and presence of DBPs is dependent on a number of factors, including the chemical disinfectant used, water quality conditions such as the content and amount of organic matter, pH, temperature, disinfection method used, and duration of treatment (how long disinfectant is in contact with the water, which means that if a person lives on the very outer edge of the water distribution system, the person will have higher levels of DBPs in the water than someone right next to the water treatment facility). Other factors include the combination or sequential use of multiple disinfectants or oxidants. Furthermore, the composition of the DBP mixture may change seasonally. The highest levels of DBPs are expected to be formed in water derived from surface sources (such as rivers, lakes, or reservoirs) because ground water usually contains little organic matter. About 500 different chlorination byproducts have been identified, including haloacetic acids (HAAs) and trihalomethanes (THMs), which are the most prevalent byproducts and some of which are carcinogenic to experimental animals. However, none of the individual DBPs dominates the toxicity of this mixture and potential chemically-related toxicity or health effects are a function of exposure to the DBP mixture. Some people who drink water containing HAA5 in excess of EPA's standard and over many years may experience health problems of the liver, kidney, or central nervous system and increased risk of developing some cancers (such as bladder, rectal, and colon cancer), especially cancer of the urinary bladder (http://www.who.int/ipcs/publications/ehc/ehc_216/en/; http://monographs.iarc.fr/ENG/Monographs/vol84/). HAAs have also been shown to cause adverse reproductive and developmental effects in experimental animal studies (such as reduced sperm motility). Among a few human studies evaluating the association between exposure to DBPs and reproductive and developmental effects or adverse pregnancy/birth outcomes, some suggested an increased risk from exposure to DBPs while others have shown none. Although findings about adverse pregnancy outcomes have not been definitive, DBPs have been implicated in fetal loss and a variety of adverse birth outcomes, including growth retardation and birth defects (e.g., neural tube defects). Note that exposure to HAAs in drinking water may also occur by inhalation or skin absorption, in addition to ingestion of contaminated drinking water.

Notes

Data Source: New Mexico Environment Department's Drinking Water Bureau, New Mexico Safe Drinking Water Information System (SDWIS). Measured HAA5 concentrations in finished drinking water can be used to understand the distribution of potential haloacetic acids (HAAs) exposure level for populations served by community water supplies. Due to potential errors in estimating service population, the measures may overestimate or underestimate the number of potentially affected people. These measures allow for comparisons of potential HAAs exposure between the populations served by different water systems over time.

Data Source

New Mexico Environment Department, Drinking Water Bureau

Data Interpretation Issues

Measures do not account for the variability in sampling, number of sampling repeats, and variability of HAA5 concentrations within systems. HAA5 levels vary seasonally and therefore, quarterly samples may not capture maximum levels and may not even adequately reflect short-term levels. Also, HAA5 levels are variable spatially and temporary within a distribution system. HAA5 concentrations increase with time after disinfection and therefore, with distance from the water treatment plant. Furthermore, HAA5 sampling locations may change over time, which can make difficult comparisons of measurements from year to year. Better estimation of HAA5 levels would require spatial and hydraulic modeling of contaminant distribution systems. Beginning October 1, 2013, Stage 2 Disinfection By Products Rules (DBPR) became effective. Systems are required to evaluate their distribution system and identify the locations with high HAA5, referred to as the locational running annual average (LRAA). Haloacetic acids typically continue to form in the distribution system over time so the highest concentration of these are most often found at sites located in areas with low but existing disinfectant residual (above 0.2 mg/L chlorine) and often downstream of storage facilities, near the ends of the distribution system, at or before the last group of customers and areas where two sources of water mix. Thus, this is where sampling locations for HAA5 are most appropriately located (the Maximum Retention Time or MRT Site). Finally, concentrations in drinking water cannot be directly converted to exposure estimates, because water consumption varies by climate, level of physical activity, and between people. Due to potential errors in estimating service population, the measures may overestimate or underestimate the number of potentially affected people.

Definition

Haloactic acids (five) or HAA5 concentrations (measured as the sum of the concentrations of monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid, and dibromoacetic acid in micrograms of HAA5 per liter of water or mcg/L) in community drinking water systems (CWS) are used in conjunction with information about each CWS (such as service population and latitude and longitude of representative location of the CWS service area) to generate the following measures shown in this report: 1) statewide HAA5 concentration distribution in CWSs by mean and maximum over time, 2) annual distribution of mean and maximum HAA5 concentration for persons served by CWS and 3) annual distribution of mean and maximum HAA5 concentration by CWS. EPHT data queries -- https://nmtracking.org/dataportal/query/selection/water/WaterSelection.html -- provide detailed results by year for 1) mean HAA5 concentration by CWS for a select year, 2) maximum HAA5 concentration by CWS for a select year, 3) mean HAA5 concentration and the number of CWS by year, 4) maximum HAA5 concentration and the number of CWS by year, 5) mean HAA5 concentration and the number of persons served by year, 6) maximum HAA5 concentration and the number of persons served by year, 7) quarterly distribution of number of CWS by mean HAA5 concentration or 8) quarterly distribution by number of people served by mean HAA5 concentration. Additionally, users may query the number of persons served and the number of CWS in the state for a select year. A CWS is a public water system (PWS) that serves year-round residents of a community, subdivision, or mobile home park that has at least 15 service connections or an average of at least 25 residents. These CWSs are a subset of all New Mexico PWSs. To measure HAA5 concentration in CWS, drinking water samples are usually taken at entry points to the distribution system or representative sampling points after water treatment has occurred.

Numerator

Concentration of HAA5.

Denominator

Not applicable.

Healthy People Objective: EH-5, Reduce waterborne disease outbreaks arising from water intended for drinking among persons served by community water systems

U.S. Target: 2 outbreaks

Other Objectives

CDC Environmental Public Health Tracking, Nationally Consistent Data and Measures (EPHT NCDM)

What Is Being Done?

Haloacetic acids five (HAA5) are a group of five chemicals (monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid, and dibromoacetic acid) formed when chlorine or other disinfectants such as chloramine, used to control pathogens, react primarily with naturally occurring organic matter in the water. HAA5 levels in drinking water from most community water systems (CWS) are low; however, there is wide variation in the levels of HAA5 found in CWS supplies across New Mexico. Regulation of HAA5 under the Safe Drinking Water Act began with the Stage 1 Disinfectants and Disinfection Byproducts Rule of 1998 (Stage 1 DBPR), which set a drinking water standard or Maximum Contaminant Level (MCL) for HAA5, defined as the sum of concentrations in micrograms per liter (mcg/L) of the five haloactic acid compounds (monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid, and dibromoacetic acid) of 60 mcg/L or 60 parts per billion (60 ppb), rounded to two significant figures after addition, for all CWS that disinfect. Community systems' drinking water is routinely monitored and tested for HAA5 by CWS to comply with the 60 mcg/L EPA standard (http://www.gpoaccess.gov/ecfr/). In NM, HAA5 monitoring framework or water sampling frequency varies among water systems depending on the water source (ground or surface water), population of residents served (less than 500, 500 or greater but less than 10,000 and 10,000 and greater), number of treatment plants and levels of HAA5 measured at location representing maximum residence time; (1) water systems using only ground water routinely sample with one water sample per treatment plant, and if serving at least 10,000 persons, then sample every quarter whereas those with smaller populations sample annually during the month with the warmest water temperature, (2) water systems using only ground water may reduce monitoring frequency to once a year at the location reflecting maximum residence time during the warmest water month of the year if serving at least 10,000 person and annual average HAA5 concentration is less than or equal to the MCL or, if the systems serves less than 10,000 persons, then samples are collected once every three years, (3) water systems using surface water and serving fewer than 500 persons routinely sample once a year at the location reflecting maximum residence time during the warmest water month of the year, (4) water systems using surface water and serving from 500 to under 10,000 persons routinely sample once per quarter per treatment plant, (5) water systems using surface water and serving from 500 to under 10,000 persons may reduce monitoring frequency to sample once per year per treatment plant at the location reflecting maximum residence time during the warmest water month of the year, (6) water systems using surface water and serving at least 10,000 persons routinely sample four times per quarter per treatment plant and (7) water systems using surface water and serving at least 10,000 persons may reduce monitoring frequency to sample once per treatment plant per quarter per year if annual average HAA5 is half or less of the MCL. Stage I DBPR monitoring sunset September 30, 2013. Beginning October 1, 2013, all CWSs became responsible for Stage 2 DBPR Compliance monitoring. Systems were required to evaluate their distribution system and identify the locations with high HAA5. CWS serving at least 10,000 began April 1, 2012. CWS serving 50,000 to 99,999 began compliance October 1, 2012. Compliance with the maximum contaminant levels was calculated for each location in the distribution system. This approach, referred to as the locational running annual average (LRAA), differs from the Stage 1 requirements, which determine compliance by calculating the running annual average of samples from all system monitoring locations.

Evidence-based Practices

Every year, CWS send to their customers a consumer confidence report (also called a water quality report) that lists any levels of HAA5 measured. EPA also requires all CWS to give their customers public notice when their water supply violates the HAA5 standard. This would include information about what is being done to correct the situation. Other actions may be required to prevent serious health risk to drinking water customers, such as providing alternative drinking water supplies. However, people who use their private wells water for drinking are solely responsible for disinfecting and testing the water for HAAs (for information about chlorination of private well water and laboratories certified to test drinking water and certified home treatment units visit: https://nmtracking.org/environment/water/PrivateWells.html).

Health Program Information

Water in which DBPs are present is a very complex mixture. Formation and presence of DBPs is dependent on a number of factors, the chemical disinfectant(s) used, water quality conditions such as the content and amount of organic matter, pH, temperature, disinfection method used, and duration of treatment (how long disinfectant is in contact with the water, which means that if a person lives on the very outer edge of the water distribution system, the person will have higher levels of DBPs in the water than someone right next to the water treatment facility). Other factors include the combination or sequential use of multiple disinfectants or oxidants. Furthermore, the composition of the DBP mixture may change seasonally. The highest levels of DBPs are expected to be formed in water derived from surface sources (such as rivers, lakes, or reservoirs) because ground water usually contains little organic matter.
Page Content Updated On 03/22/2018, Published on 03/22/2018
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Content updated: Thu, 22 Mar 2018 15:34:35 MDT