DefinitionTetrachloroethylene or perchloroethylene (PCE) concentrations (in micrograms of PCE 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 PCE concentration distribution in CWSs by mean and maximum over time, 2) annual distribution of mean and maximum PCE concentration for persons served by CWS and 3) annual distribution of mean and maximum PCE concentration by CWS.
EPHT data queries -- https://nmtracking.org/dataportal/query/selection/water/WaterSelection.html -- provide detailed results by year for
1) mean PCE concentration by CWS for a select year,
2) maximum PCE concentration by CWS for a select year,
3) mean PCE concentration and the number of CWS by year,
4) maximum PCE concentration and the number of CWS by year,
5) mean PCE concentration and the number of persons served by year or
6) maximum PCE 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.
NumeratorConcentration of PCE.
Data Interpretation IssuesTo measure the PCE 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. Furthermore, concentrations in drinking water cannot be directly converted to exposure because water consumption varies by climate, level of physical activity, and between persons. In addition, households may have installed water treatment systems at the tap which may reduce exposure. 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 results in over- or underestimated PCE concentration in CWS drinking water during 1999-2004.
Why Is This Important?PCE is a nonflammable colorless liquid. It is a chlorinated solvent commonly used as a dry cleaner, fabric finisher, degreaser, rug and upholstery cleaner, paint and stain remover, and a chemical intermediate in manufacturing other chemicals and is used in some consumer products, including printing ink, glues, sealants, polishes, and lubricants (1).
PCE is present in the environment from its past and recent industrial releases or other uses. It has been found in soil, ground water and surface water as a result of its use in manufacture, consumer products and disposal practices. It is one of the most frequently (the 3rd most common) found chemical contaminant in ground water at hazardous waste sites. People who live near facilities that use PCE or near hazardous waste sites containing PCE may have a higher exposure to PCE. It readily separates from contaminated soil and water into the air. However, when it leaches deeper into subsurface soil, it does not break-down readily. Also, it is expected to remain in ground water for long periods of time, because it cannot readily evaporate from groundwater as it would from surface waters. In air, it breaks down very slowly and can travel long distances.
The highest exposure to PCE occurs in occupational setting from inhalation of airborne PCE. For the general public, PCE-contaminated drinking water and air are the most important sources of exposure to this solvent. PCE may enter indoor air from contaminated soils or shallow ground water through cracks in the foundation of a building or from household uses of PCE-containing water, including from dishwashing, bathing, showering, or flushing toilets.
Ingestion of PCE-containing drinking water and inhalation of PCE-contaminated air are the major routes of exposure for the general population. It is well absorbed into the human body from the lungs, gastrointestinal tract, and skin. Chronic inhalation exposure to high amounts of PCE may adversely affect the nervous system, liver, kidneys, and reproductive systems (1). These effects have been linked to exposures, primarily in occupational setting, such as in dry cleaning industry. People who are exposed to PCE for long periods of time to lower levels of PCE in air may have changes in mood, memory, attention, reaction time, or vision. Although human studies are not clear about PCE effects on pregnancy and unborn children, studies in animals suggest possibility that PCE may lead to miscarriages, some birth defects (e.g., orofacial clefts), and slowed growth of the baby following ingestion and inhalation exposure of some people.
Furthermore, exposure to PCE for a long time may lead to a higher risk of getting cancer, however, the type of cancer that may develop is not well-understood, but associations have been seen for cancer of the urinary bladder (1, 2). The results of many epidemiological studies of cancer incidence and mortality in groups of workers exposed occupationally to PCE are equivocal and do not support a cause-and -effect relationship between PCE and cancer. This is why the EPA considers PCE likely to be carcinogenic to humans by all routes of exposure based on suggestive evidence in human studies (1) and the International Agency for Research on Cancer (IARC) classified PCE as probably carcinogenic to humans or Group 2A carcinogen, based on limited evidence in humans and sufficient evidence in animals (2).
References: (1) (http://www.atsdr.cdc.gov/toxprofiles/tp18.pdf ); (2) http://monographs.iarc.fr/ENG/Monographs/vol106/mono106-002.pdf.
Other ObjectivesCDC Environmental Public Health Tracking, Nationally Consistent Data and Measures (EPHT NCDM).
Environmental Health Epidemiology Bureau, Environmental Public Health Tracking Program, New Mexico Department of Health, 1190 S. Saint Francis Drive, Suite 1320, Santa Fe, NM 87505, Heidi Krapfl, Chief, (505) 476-3577, email@example.com, or Brian Woods, Environmental Epidemiologist, (505) 827-2868, firstname.lastname@example.org
What Is Being Done?In 2014, PCE levels in drinking water from CWS in New Mexico were below the Environmental Protection Agency (EPA)-established drinking water standard or Maximum Contaminant Level (MCL) for PCE of 5 micrograms per liter (5 mcg/L) or 5 parts per billion (5 ppb) (Safe Drinking Water Act (SDWA). This MCL is the highest level of PCE, which is allowed in drinking water and it is the enforceable standard. Community systems' drinking water is routinely monitored and tested for PCE by CWS to comply with the 5 mcg/L EPA standard for PCE. Every year, CWS send to their customers a consumer confidence report (also called a water quality report) that lists any levels of PCE measured. EPA also requires all CWS to give their customers public notice when their water supply violates the PCE standard. This would include information about what is being done to correct the situation. However, people who use their private wells water for drinking are solely responsible for testing the water for PCE (for information about laboratories certified to test drinking water and certified home treatment units visit https://nmtracking.org/environment/water/private_wells/Testing.html). The health effects in people using water containing PCE in excess of EPA's standard for drinking water and other household uses (such as bathing, showering, and dishwashing) over many years are mainly unknown. However, some people may experience health problems, as discussed above and may develop certain cancers (such as the urinary bladder).