Health Indicator Report of Community Water: Di (2-ethylhexyl)phthalate (DEHP) Concentration
DEHP is a man-made chemical commonly added to plastics to increase their elasticity. It is a colorless oily liquid with a slight odor (http://www.atsdr.cdc.gov/toxprofiles/index.asp). It is slightly soluble in water. It is lipophilic and therefore, soluble in blood and body fluids containing lipoproteins. Most (about 95%) of DEHP produced is added as a plasticizer to polyvinyl chloride (PVC) for manufacturing flexible vinyl products. A long list of PVC products containing DEHP includes tablecloths, shower curtains, furniture and automobile upholstery, imitation leather, garden hoses, vinyl floor tiles and flooring, swimming-pool liners, sheathing for wire and cable, rainwear, shoes, toys, dolls, food packaging materials, tubing used in commercial milking equipment, weather stripping and medical devices, such as blood and intravenous solution bags, catheters, tubing for dialysis and intravenous solutions, and oxygen masks. Due to its widespread use in plastics, DEHP may be present everywhere in the environment, including air, soil, water, plants, fish, and other animals. DEHP in soil, water, and animals high on the food chain can be broken down by microorganisms into harmless chemicals, with gaseous carbon dioxide being one of the main products (http://www.atsdr.cdc.gov/toxprofiles/index.asp). It does not break down easily when present in the deep soil or on the bottom of lakes and rivers, as it attaches strongly to soil/sediment particles. For the general public, ingestion of contaminated drinking water and food, inhalation of contaminated indoor air, and exposure through medical procedures are the primary pathways of potential exposure to DEHP (http://www.atsdr.cdc.gov/toxprofiles/index.asp).
NotesData Source: New Mexico Environment Department's Drinking Water Bureau, New Mexico Safe Drinking Water Information System (SDWIS). Measured DEHP concentrations in finished drinking water can be used to understand the distribution of potential DEHP 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 comparison of potential DEHP exposure between the populations served by different water systems over time.
Data SourceNew Mexico Environment Department, Drinking Water Bureau
Data Interpretation IssuesTo measure DEHP 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. Measures do not account for the variability in sampling, number or sampling repeats, etc. Every effort is made to evaluate samples to ensure quality; however, there may still be artifacts in some analytical data, due to potential for adsorption of some contaminants (such as DEHP) to sample containers or other random issues that may occur at different stages of sample collection, preparation and laboratory analyses. Furthermore, concentrations in drinking water cannot be directly converted to exposure 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. In addition, the older data (i.e., 1999 through 2004) may be of poor quality that could result in over- or under-estimated DEHP concentration in CWS drinking water.
DefinitionDi(2-ethylhexyl)phthalate (DEHP) concentrations (in micrograms of DEHP per liter of water or mcg/L) in community drinking water systems (CWS) are combined with information about each CWS (such as service population) to generate the following measures shown in this report: 1) statewide DEHP concentration distribution in CWSs by mean and maximum over time, 2) annual distribution of mean and maximum DEHP concentration for persons served by CWS and 3) annual distribution of mean and maximum DEHP concentration by CWS. EPHT data queries -- https://nmtracking.org/dataportal/query/selection/water/WaterSelection.html -- provide detailed results by year for 1) mean DEHP concentration by CWS for a select year, 2) maximum DEHP concentration by CWS for a select year, 3) mean DEHP concentration and the number of CWS by year, 4) maximum DEHP concentration and the number of CWS by year, 5) mean DEHP concentration and the number of persons served by year or 6) maximum DEHP concentration and the number of persons served by year. 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 radium 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.
NumeratorConcentration of DEHP.
How Are We Doing?The use of DEHP as a plasticizer has been declining in the U.S. and Europe due to concerns about its potential toxicity. It is being replaced with other plasticizers that may have lower toxicity. For example, it was the most common plasticizer used in pacifiers, rattles, and teethers until the early 1980s, when manufacturers voluntarily agreed to eliminate intentional addition of DEHP. The U.S. Congress (the Consumer Product Safety Improvement Act (CPSIA) of 2008) has permanently banned three types of phthalates, including DEHP, in any amount greater than 0.1 percent (calculated for each phthalate individually) in children's toys and any child care article that is designed or intended by the manufacturer to facilitate sleep or the feeding of children age 3 and younger with sucking or teething (http://www.cpsc.gov/en/Business--Manufacturing/Business-Education/Business-Guidance/Phthalates-Information/). Furthermore, it is no longer used in plastic food wrap products manufactured in the U.S. (http://toxnet.nlm.nih.gov/cgi-bin/sis/search2/f?./temp/~iLKSIm:1).
What Is Being Done?DEHP can enter drinking water mainly from its discharge from rubber and chemical factories or as run-off into surface water sources. DEHP levels in drinking water from most (about 99% in 2014) CWS in New Mexico were below the EPA-established drinking water standard or Maximum Contaminant Level (MCL) for DEHP of 6 micrograms per liter (6 mcg/L) or 6 parts per billion (6 ppb) to protect public health (EPA, 2001; 40CFR141.32(e)(62); 40CFR141.61c; http://www.ecfr.gov). The EPA?s Phase V Rule, the regulation for DEHP, became effective in 1994. This MCL is the highest level of DEHP which is allowed in drinking water and it is the enforceable standard. Community systems' drinking water is routinely monitored and tested for DEHP by CWS to comply with the 6 mcg/L EPA standard for DEHP. Every year, each CWS sends their customers a consumer confidence report (also called a water quality report) that lists any levels of DEHP measured. EPA also requires all CWS to give their customers public notice when their water supply violates the DEHP standard. This would include information about what is being done to correct the situation. However, in New Mexico, people who use their private wells water for drinking are solely responsible for testing the water for DEHP (for information about laboratories certified to test drinking water and certified home treatment units visit https://nmtracking.org/environment/water/private_wells/Testing.html). Some people who drink water containing DHEP in excess of EPA standard and over many years may experience health problems of the liver or could experience reproductive difficulties and may have an increased risk of getting liver cancer.
Health Program InformationHuman data indicate that approximately 55% of ingested DEHP and its degradation products or metabolites in water or food is absorbed from the gastrointestinal tract. DEHP does not appear to be efficiently absorbed through the human skin; only trace amounts of DEHP might be absorbed through the intact skin. Following ingestion exposure, most of DEHP is broken down or metabolized in the body to over 30 metabolites, which after absorption rapidly leave the human body in the urine. Depending on the amount ingested, most (approximately 65%) of DEHP metabolites are removed from the body by the kidneys and eliminated primarily in urine within a 24 hours (http://www.atsdr.cdc.gov/toxprofiles/index.asp). Approximately 20-25% of the absorbed DEHP (mainly un-metabolized) leaves the body in the feces. Urinary and blood DEHP and its metabolites can be used as biomarkers of exposure. DEHP and its metabolites absorbed into the bloodstream are distributed to the various organs, including the liver, kidneys, testes, and other tissues. Because DEHP is lipophilic, it tends to accumulate in fat and fatty (adipose) tissues and it was found in human kidneys; small amounts of DEHP or its metabolites could be secreted in breast milk. Health effects of exposure to DEHP are determined by its exposure dose or amount (how much), the duration and frequency of exposure (for how long and how often), and the route of exposure (e.g., ingestion, inhalation, skin contact). Most of the knowledge about possible DEHP toxicity comes from studies of laboratory animals (mainly rats and mice) given high amounts of the chemical orally. Human toxicity data are limited to gastrointestinal effects following ingestion of high amounts (10 grams or approximately 0.4 ounces) of DEHP. DEHP and its putative toxic metabolite mono(2-ethylhexyl)phthalate caused liver toxicity, decreased testicular weight, and testicular atrophy and decreased fertility in rodents fed with high amounts of the chemicals over a short-term or chronic exposure duration (http://www.atsdr.cdc.gov/toxprofiles/index.asp; http://www.cdc.gov/biomonitoring/DEHP_BiomonitoringSummary.html). However, no liver toxicity nor testicular atrophy were seen in other studies such as of marmoset monkeys fed very high amounts of DEHP for over a year. Other studies demonstrated suppression of estradiol (a form of estrogen which is a female sex hormone) production in female rats administered high doses of DEHP. Because rats and mice may be exceptionally sensitive to some of the DEHP toxicities (e.g., to the liver), some of those toxic effects may not occur in humans and primates. EPA determined that DEHP is a probable human carcinogen (Group B2), based on inadequate human evidence and adequate evidence for cancer (liver cancers or hepatocellular carcinoma and adenoma) in laboratory animals fed high amounts of DEHP in food for most of their lives (http://cfpub.epa.gov/ncea/iris/search/index.cfm?keyword=117-81-7). Based on the same evidence, the International Agency for Research on Cancer (IARC) determined that DEHP is possibly carcinogenic to humans (Group 2B) (http://monographs.iarc.fr/ENG/Classification.index.php). The U.S. Department of Health and Human Services (DHHS) has determined that DEHP is reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity (hepatocellular adenoma and/or carcinoma) from studies in experimental animals (mice and rats of both sexes with tumor incidences showing significant dose-related trends in both species (http://ntp.niehs.nih.gov/pubhealth/roc/index.html).
Page Content Updated On 04/17/2019, Published on 04/17/2019