New insight on vulnerability of public-supply wells to contamination

August 5, 2013

Key factors have been identified that help determine the vulnerability of public-supply wells to contamination. A new USGS report describes these factors, providing insight into which contaminants in an aquifer might reach a well and when, how and at what concentration they might arrive.

About one-third of the U.S. population gets their from public-supply wells.

"Improving the understanding of the vulnerability of public-supply wells to contamination is needed to safeguard public health and prevent future contamination," said Suzette Kimball, acting USGS Director. "By examining ten different aquifers across the nation, we have a more thorough and robust understanding of the complexities and factors affecting water quality in our public supplies."

The study explored factors affecting public-supply-well vulnerability to contamination in ten study areas across the Nation. The study areas include Modesto, Calif., Woodbury, Conn., near Tampa, Fla., York, Nebr., near Carson City and Sparks, Nev., Glassboro, N. J., Albuquerque, N. Mex., Dayton, Ohio, San Antonio, Tex., and Salt Lake City, Utah.

Measures that are crucial for understanding public-supply-well vulnerability include: 1) the sources of the water and contaminants in the water that infiltrate the ground and are drawn into a well; 2) the geochemical conditions encountered by the groundwater; and 3) the range of ages of the groundwater that enters a well.

"Common sense might say that wells located near known contaminant sources would be the most vulnerable, but this study found that even where contaminant sources are similar, there are differences in public-supply-well vulnerability to contamination," said Sandra Eberts, the study team leader.

The study found that conditions in some aquifers enable contaminants to remain in the groundwater longer or travel more rapidly to wells than conditions in other aquifers. Direct pathways, such as fractures in rock aquifers or wellbores of non-pumping wells, frequently affect groundwater and contaminant movement, making it difficult to identify which areas at land surface are the most important to protect from contamination. An unexpected finding is that human-induced changes in recharge and groundwater flow caused by irrigation and high-volume pumping for public supply changed aquifer geochemical conditions in numerous study areas. Changes in often release naturally occurring drinking-water contaminants such as arsenic and uranium into the groundwater, increasing concentrations in public-supply wells.

Knowledge of how human activities change aquifer conditions that control which contaminants are released to groundwater and how persistent those contaminants are once in the groundwater can be used by water managers to anticipate future water quality and associated treatment costs.

The quality of drinking water from the Nation's public water systems is regulated by the U.S. Environmental Protection Agency under the Safe Drinking Water Act. The USGS studies are intended to complement drinking water monitoring required by federal, state and local programs.

Explore further: Contaminants in groundwater used for public supply

More information: oh.water.usgs.gov/tanc/NAWQATANC.htm

Related Stories

Contaminants in groundwater used for public supply

May 21, 2010

More than 20 percent of untreated water samples from 932 public wells across the nation contained at least one contaminant at levels of potential health concern, according to a new study by the U.S. Geological Survey.

Groundwater a viable resource for Malaysians

September 5, 2012

A report on productive aquifers in hard rock on the west coast of Peninsular Malaysia suggests greater water supply than has previously been recognised. The work, published in the Pertanika Journal of Science and Technology, ...

How does groundwater pumping affect streamflow?

November 16, 2012

Groundwater provides drinking water for millions of Americans and is the primary source of water to irrigate cropland in many of the nations most productive agricultural settings. Although the benefits of groundwater development ...

Recommended for you

Scientists reveal origin of Earth's oldest crystals

April 28, 2016

New research suggests that the very oldest pieces of rock on Earth—zircon crystals—are likely to have formed in the craters left by violent asteroid impacts that peppered our nascent planet, rather than via plate tectonics ...

Geochemical detectives use lab mimicry to look back in time

April 28, 2016

New work from a research team led by Carnegie's Anat Shahar contains some unexpected findings about iron chemistry under high-pressure conditions, such as those likely found in the Earth's core, where iron predominates and ...

New maps chart Greenland glaciers' melting risk

April 22, 2016

Many large glaciers in Greenland are at greater risk of melting from below than previously thought, according to new maps of the seafloor around Greenland created by an international research team. Like other recent research ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.