Important Facts for Drinking Water: DEHP (Di [2-Ethylhexyl] phthalate)

Definition

__Mean DEHP (Di [2-Ethylhexyl] phthalate) Levels for Utah__[[br]] 1) Yearly distribution of number of community water systems (CWS) by mean DEHP concentration 2) Yearly distribution of number of people served by CWS by mean DEHP concentration __Maximum DEHP Levels for Utah__[[br]] 3) Yearly distribution of number of CWS by maximum DEHP concentration 4) Yearly distribution of number of people served by CWS by maximum DEHP concentration

Numerator

1) Count of community water systems categorized by mean DEHP (Di [2-Ethylhexyl] phthalate) concentration for each year reported (cut-points: <=6, >6 ug/L DEHP, Not Detected) 2) Number of people served by community water systems categorized by mean DEHP concentration for each year reported (cut-points: <=6, >6 ug/L DEHP, Not Detected) 3) Count of community water systems categorized by maximum DEHP concentration for each year reported (cut-points: <=6, >6 ug/L DEHP, Not Detected) 4) Number of people served by community water systems categorized by maximum DEHP concentration for each year reported (cut-points: <=6, >6 ug/L DEHP, Not Detected)

Denominator

Not applicable.

Data Interpretation Issues

These calculations include all available data which varies by year and water system. This data does not include information about private water sources such as well water or tribal water systems. Population data for each community water system (CWS) are estimated based on number of connections. A CWS is a public water system which serves at least 15 service connections used by year-round residents or regularly serves at least 25 year-round residents. The current measures are derived for community water systems (CWS) only. Private wells may be another source of population exposure to DEHP (Di [2-Ethylhexyl] phthalate). Transient non-community water systems, which are regulated by EPA, may also be an important source of DEHP exposure. Measures do not account for the variability in sampling, numbers of sampling repeats, and variability within systems. Concentrations in drinking water cannot be directly converted to exposure, because water consumption varies by climate, level of physical activity, and between people (EPA 2004). Due to errors in estimating populations, the measures may overestimate or underestimate the number of affected people. (From the National Environmental Public Heath Tracking Network [NEPTHN] Nationally Consistent Data and Measures [NCDM] DEHP indicator document, version 4) Ground water systems may have many wells with different DEHP concentrations that serve different parts of the population. Compliance samples are taken at each entry point to the distribution system. In systems with separate wells serving some branches or sections of the distribution system, the system mean would tend to underestimate the DEHP concentration of people served by wells with higher DEHP concentrations. Exposure may be higher or lower than estimated if data from multiple entry points for water with different DEHP levels are averaged to estimate levels for the CWS. (Modified from the National Environmental Public Heath Tracking Network [NEPTHN] Nationally Consistent Data and Measures [NCDM] DEHP indicator document, version 4)

Why Is This Important?

People drink and use water every day. The majority of Americans are provided with high quality drinking water. About 90% of people in the U.S. get their water from a community water system versus a smaller water supply, such as a household well. The U.S. Environmental Protection Agency (EPA) sets regulations for treating and monitoring drinking water delivered by community water systems. Currently, there are water quality standards and monitoring requirements for over 90 contaminants. Drinking water protection programs play a critical role in ensuring high quality drinking water and protecting the public's health. Because people drink and use water every day, contaminants in drinking water have the potential to affect many people. The number of people served by a community water system varies from as low as 25 to hundreds of thousands. Community water systems in the U.S. provide among the highest quality drinking water in the world. However, some contaminants are present at low levels and it is still possible that drinking water can become contaminated at higher levels. If a person is exposed to a high enough level of a contaminant, they may become ill. Most of what we know about the health effects of DEHP (Di [2-Ethylhexyl] phthalate) comes from studies of rats and mice given high amounts of DEHP. Brief oral exposure to very high levels of DEHP damaged sperm in mice. Although the effect reversed when exposure ceased, sexual maturity was still delayed in the animals. High amounts of DEHP damaged the liver of rats and mice. Whether or not DEHP contributes to human kidney damage is unclear. (Nationally Consistent Data and Measures [NCDM] version 3). DEHP is the most commonly used group of related chemicals called phthalates or phthalic acid esters. Some people who drink water containing DEHP well in excess of the maximum contaminant level (MCL) for many years may have problems with their liver, experience reproductive difficulties, or have an increased risk of getting cancer (U.S. EPA, 2010). (Modified from the National Environmental Public Health Tracking Network [NEPHTN] Nationally Consistent Data and Measures [NCDM] DEHP indicator document, version 4) The Department of Health and Human Services has determined that DEHP may reasonably be anticipated to be a human carcinogen. The Environmental Protection Agency (EPA) has determined that DEHP is a probable human carcinogen. These determinations were based entirely on liver cancer in rats and mice. The International Agency for Research on Cancer has stated that DEHP cannot be classified as to its carcinogenicity to humans. (From the National Environmental Public Health Tracking Network [NEPHTN] Nationally Consistent Data and Measures [NCDM] DEHP indicator document, version 4)