42 million Americans use groundwater vulnerable to contamination by volatile organic compounds

October 27, 1999

Researchers with the U.S. Geological Survey estimate that 42 million Americans use groundwater vulnerable to low-level contamination by volatile organic compounds (VOCs). The estimate is based on the first nationwide assessment of untreated groundwater aquifers, which found VOC levels in excess of federal drinking water criteria in about 6 percent of urban wells and 1.5 percent of rural wells. The amount of human exposure to the VOCs is uncertain, according to the researchers.

The research, involving water samples collected between 1985-1995 from nearly 3,000 wells throughout the United States, will be published Oct. 29 in the web edition of the journal Environmental Science & Technology. The report is scheduled to appear in the Dec. 1 print edition of the peer-reviewed journal, which is published by the American Chemical Society, th7e world's largest scientific society.

Researchers examined water quality of many of the nation's principal aquifers as part of the study, according to the report's lead author Paul Squillace, a research hydrologist with the U.S. Geological Survey office in Rapid City, S.D. The sampled wells were primarily located along the east and west coasts, and in the central United States.

"The samples were collected to represent the groundwater quality in the aquifer and not the water quality at the tap," says Squillace. "This resource assessment is the first national scale assessment of [untreated] drinking water aquifers," he claims. The U.S. Environmental Protection Agency requires states to routinely monitor the quality of treated water.

The study concludes that people in the eastern half of the United States are more likely to live in areas where groundwater contains VOCs than people in the western half of the country. It also found that people living in more populated areas, the northeast and the west coast, were most likely to use groundwater containing VOCs. "The larger the population density, the greater the detection frequency of VOCs in the aquifers," notes Squillace.

"Among all wells, untreated groundwater in urban areas was four times more likely to exceed a drinking-water criterion than untreated groundwater in rural areas," according to the report.

Chlorination of public water, the most common treatment method, generally does not reduce VOC contamination, says Squillace. However, he notes, treatment facilities routinely monitor for VOCs and must use other treatment methods, such as aeration, if levels get above allowable limits. Such is not the case with private wells, he adds.

Volatile organic compounds are found in a variety of products, including gasoline, paints, plastics and solvents. The gasoline additive MTBE (methyl tert-butyl ether) and solvent compounds were "among the most frequently detected VOCs in urban and rural areas," according to the report.

"VOCs can be important environmental contaminants because many are mobile, persistent and toxic," the report points out. "The U.S. EPA has established maximum contaminant levels in drinking water for 27 VOCs because of human health concerns," it adds.

The VOCs detected in aquifers commonly are mixtures of several compounds. "Because current health criteria are based on exposure to a single [VOC] contaminant, the health implications of these mixtures are not known," Squillace emphasizes.

How much actual human exposure there might be to VOCs in aquifers is "uncertain," says Squillace. But, since so many people obtain their water from aquifers, "monitoring and proactive protection of these aquifers would seem prudent," he says.
-end-
Additional information and figures:
(figure 1)
U.S. Geological Survey researchers used water samples collected from 2,948 wells nationwide over a ten year period to evaluate the water quality of many of the country¹s principal aquifers. Contamination by volatile organic compounds, such as solvents and the gasoline additive MTBE, exceeded federal drinking water criteria in 6.4 percent of urban wells and 1.5 percent of rural wells. (Graphic published by Environmental Science & Technology, courtesy of USGS

(figure 6)
Volatile organic compounds, such as solvents and the gasoline additive MTBE, are more likely to be found in groundwater in densely populated areas of the country, particularly in the eastern half of the U.S., according to U.S. Geological Survey researchers. The estimates are based on a USGS study of nearly 3,000 wells nationwide. (Graphic published by Environmental Science & Technology, courtesy of USGS)

A nonprofit organization with a membership of nearly 159,000 chemists and chemical engineers, the American Chemical Society publishes scientific journals and databases, convenes major research conferences, and provides educational, science policy and career programs in chemistry. Its main offices are in Washington, D.C., and Columbus, Ohio. ( http://www.acs.org )

American Chemical Society

Related Water Quality Articles from Brightsurf:

A watershed moment for US water quality
A new federal rule that determines how the Clean Water Act is implemented leaves millions of miles of streams and acres of wetlands unprotected based on selective interpretation of case law and a distortion of scientific evidence, researchers say in a new publication.

'Pregnancy test for water' delivers fast, easy results on water quality
A new platform technology can assess water safety and quality with just a single drop and a few minutes.

New process could safeguard water quality, environment and health
Swansea University researchers have developed a new way to quickly find and remove wastewater pollutants, which can reduce their impact on the environment.

23 years of water quality data from crop-livestock systems
Researchers summarize runoff water quantity and quality data from native tallgrass prairie and crop-livestock systems in Oklahoma between 1977 and 1999.

Lessening water quality problems caused by hurricane-related flooding
June 1 is the start of hurricane season in the Atlantic, and with 2020 predicted to be particularly active, residents in coastal regions are keeping watchful eyes on the weather.

Control of anthropogenic atmospheric emissions can improve water quality in seas
A new HKU research highlighted the importance of reducing fossil fuel combustion not only to curb the trend of global warming, but also to improve the quality of China's coastal waters.

Pharma's potential impact on water quality
When people take medications, these drugs and their metabolites can be excreted and make their way to wastewater treatment plants.

Study: Your home's water quality could vary by the room -- and the season
A study has found that the water quality of a home can differ in each room and change between seasons, challenging the assumption that the water in a public water system is the same as the water that passes through a building's plumbing at any time of the year.

Researchers create new tools to monitor water quality, measure water insecurity
A wife-husband team will present both high-tech and low-tech solutions for improving water security at this year's American Association for the Advancement of Science (AAAS) annual meeting in Seattle on Sunday, Feb.

How anti-sprawl policies may be harming water quality
Urban growth boundaries are created by governments in an effort to concentrate urban development -- buildings, roads and the utilities that support them -- within a defined area.

Read More: Water Quality News and Water Quality Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.