By Marianne Metzger

In March, US EPA administrator Lisa Jackson announced there were going to be major changes to how drinking water is regulated. There are four strategies the agency hopes to implement in order to improve protection of our drinking water.

Strategy 1. Contaminant groups
New adjustments in policy will allow regulators to look at groups of contaminants that are similar, and issue new regulations that would apply to several contaminants. Current regulations call for examination of one pollutant at a time, which is painstakingly slow and allows many people to be exposed to chemicals that pose health risks during the evaluation process.

Strategy 2. Technology promotion
The agency will promote development of new drinking water technologies to address health concerns posed by the broad spectrum of contaminants being found in drinking water. It expects to accomplish this by collaborating with universities, technology developers and the private sector to develop new or improved water and energy-efficient treatment technologies to reduce health-based contaminants that are and will continue to confront water utilities.

Strategy 3. Statute authority
US EPA will use the authority of other statutes in an effort to help protect drinking water. Specifically, the Federal Insecticide, Fungicide, Rodenticide Act (FIFRA) requires registration of chemicals being used as pesticides. US EPA plans to use these registrations to develop risk assessments and analytical methods in support of developing new drinking water regulations. Toxic Substance Control Act (TSCA) is another statute that would be useful in the development of new drinking water regulations, as it addresses production, importation, use and disposal of specific chemicals.

Strategy 4. Partnership formation
The agency will seek to form partnerships with states to share access to all public water systems monitoring data. Through the use of advanced information technology, US EPA wants to facilitate data exchange capability between the states and the agency without imposing further burden on states for information collection.

Additionally, US EPA announced it will look to make four contaminants in drinking water more strictly regulated. These contaminants include: trichloroethylene (TCE), tetrachloroethylene (PCE), acrylamide and epicholohydrin, all of which are known carcinogens. They are being considered due to the results of the second Six Year Review of the National Primary Drinking Water Regulations. It was found that, with currently available technology, these four contaminants can be further regulated to protect public health.

An in-depth look at the contaminants
Trichloroethylene is a volatile organic chemical used mainly as a degreasing agent for fabricated metals parts. It is also used in many other applications including: dry cleaning operations; textile production; organic synthesis; aerospace operations; as a household cleaner for walls, carpets and rugs; a refrigerant; a heatexchange liquid and a fumigant. It is also used as an ingredient in paints and varnishes, adhesives, pesticides, gums, resins and tar. TCE in water can be a result of the breakdown of its parent compound tetrachloroethylene (PCE). Toxicological studies indicate that animals that were exposed to levels of TCE above typical environmental levels exhibited changes in the nervous system, liver and kidney damage, tumors in the liver, kidney, lung and possibly leukemia.

US EPA is currently reviewing TCE to determine which class of carcinogen it will fall under. Under the Safe Drinking Water Act (SDWA), the agency has established a maximum contaminant level goal (MCLG) of zero for trichloroethylene. A MCLG is the level at which there are no observed health affects. The agency has established a maximum contaminant level (MCL) of 0.005 mg/L (or five parts per billion). An MCL is the enforceable standard which public water supplies are required to meet. This level is set as close to the MCLG as possible, considering available technology cost and benefit, and possible occurrence levels in drinking water.

Tetrachloroethylene (also known as PCE, Perchloroethylene and PERC) is primarily used in the dry cleaning business and textile industry. It is also used for metal degreasing and in various consumer products. Toxicological studies on animals indicate that exposure to higher PCE levels caused damage to the kidney and liver. The US Department of Health and Human Services has determined it is reasonable to conclude that PCE is a carcinogen. Currently the MCLG for tetrachloroethylene is zero, and the MCL is 0.0052 mg/L or five parts per billion.

According to the Agency for Toxic Substances and Disease Registry (ATSDR), trichloroethylene is found in 852 of 1430 National Priorities List (NPL) sites; tetrachloroethylene is found in 771 of the NPL sites, as identified by US EPA. The US Geological Survey (USGS) conducted a study about volatile organic chemicals in about 3,500 water supplies (including private wells and public water supplies), sampled between 1985 and 2002. The most commonly detected VOCs were chloroform, TCE, PCE and Methyl tert-butyl ether (MTBE). In that same study, TCE and PCE were among the VOCs that were most frequently detected above federal standards. Given the fact that TCE is a known carcinogen, and its occurrence in our water supply as well as the technology available for monitoring and treating TCE in water, the US EPA is looking at stricter requirements. In the second Six Year Review of the US EPA Primary Standards, it was found that current analytical methods would allow for laboratories to detect even lower levels, which means the agency could lower the MCL.

This will require testing methods be refined so labs are able to meet levels significantly lower than the established guideline. Public water supplies with TCE or PCE contamination may have to further upgrade water treatment technologies to reduce current levels to below the new federal standard. US EPA will start the process to revise the standards for these two compounds, but it won’t happen overnight. It could take several years before completion and implementation.

Additionally, US EPA is also considering stricter regulations for epichlorohydrin and acrylamide. Both are classified as probable carcinogens, so the agency has established an MCLG for both at a level of zero. These two compounds are, however, regulated differently than TCE and PCE; they are regulated by Treatment Techniques and have no established MCL. US EPA regulated them as treatment techniques because there were no standard analytical methods available for measurement in water. These two compounds constitute impurities in polymers and copolymers used in treating some municipal water. In order to meet the regulations, systems must certify in writing to the state (using either the manufacturer or third-party certification) that they are not exceeding specified levels. US EPA chose to regulate these compounds because methods were readily available for measurement of the residual monomer in polymer products. This was already being done by the manufacturers on a routine basis. The levels are specified as follows:

  • Acrylamide = 0.05 percent residual acrylamide in polymer/copolymers and a maximum dosage of one mg/L (or equivalent)
  • Epichlorohydrin = 0.01 percent residual epichlorohydrin in polymer/copolymer and a maximum dosage of 20 mg/L (or equivalent)

The residual monomer level for each was set at the lowest level manufacturers could feasibly achieve at the time the regulations were promulgated. New information obtained during the Six-Year Review 2 indicates that improved technology and manufacturing could now allow production of the polymer with lower residual monomer content, which means systems using these chemicals will have to meet stricter requirements on the amount of residual allowed. What does this mean for the water treatment industry? Any polymer certified by NSF 60 as a coagulant aid will need to undergo new testing in order to prove lower residual monomer levels.

While the US EPA is applauded for its outside-of-the-box thinking for upcoming regulations to protect our drinking water, only time will tell if it will indeed work. As technology advances, so should our regulations, and proposed methods of regulating these contaminants could prove to be quite beneficial to human health.

References

  1. US EPA, Office of Water, Analytical Feasibiity Support Document for the Second Six -Year Review of Existing National Primary Drinking Water Regulations. October 2009
  2. US EPA, Enesta Jones, EPA Admistrator Jackson Outlines New Vision for Clean, Safe Drinking Water, March 22, 2010
  3. United States Geological Survey, Volatile Organic Compounds in the Nation’s Ground Water and Drinking Water Supply Wells—A Summary. April 2006
  4. US EPA, www.epa.gov/safewater/contaminants/basicinformation/trichloroethylene.html
  5. US EPA, www.epa.gov/safewater/contaminants/basicinformation/tetrachloroethylene.html

About the author
Marianne R. Metzger recently rejoined National Testing Laboratories, Ltd. as the GPG Business Manager. She handles various market segments including water treatment, well drilling, public water supplies and homeowners. Metzger has a degree in environmental geology and political science from Case Western Reserve University of Cleveland. She was employed at Accent Control Systems as a sales engineer, working with water treatment equipment on commercial and industrial applications. Previously, Metzger spent over 10 years with NTL in a variety of positions including customer service, technical support and Business Group Manager. She can be reached by phone at (800) 458-3330 ext. 223 or via email at mmetzger@ntllabs.com

 

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