VOCs Turn Up in Well Water

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VOCs Turn Up in Well Water

_http://www.ehponline.org/realfiles/docs/2007/115-11/ss.html_

(http://www.ehponline.org/realfiles/docs/2007/115-11/ss.html)

Sensitive Measure Reveals Groundwater Contaminant

 

About 15% of the U.S. population get their drinking and household water from

a largely unmonitored source: private residential wells. About 400,000 new

wells are drilled every year. A new USGS study suggests that the water in a

small percentage of domestic wells could contain unsafe levels of volatile

organic compounds (VOCs) [_EHP 115:1539–1546; Rowe et al._

(http://www.ehponline.org/docs/2007/10253/abstract.html) ].

[GRAPH HERE]

 

Of 2,401 wells assayed by Rowe et al., 1% had water containing VOCs above

EPA maximum contaminant levels.

 

 

 

PAHs and PM2.5 are generated primarily by combustion of petroleum products,

coal, wood, tobacco, trash, fat, and other substances. The concentrations of

PAHs and PM2.5 in the two Czech Republic districts studied, Prachatice and

Teplice, were similar to those found in many U.S., European, and Asian cities.

VOCs come from a wide variety of sources, including gasoline, plastics,

paints, dyes, solvents, adhesives, insecticides, and spot removers, and have

wide-ranging health effects. The chemical and physical properties of VOCs allow

the compounds to move between the atmosphere, soil, surface water, and

groundwater. Once in the environment, some VOCs degrade quickly whereas others

persist for decades.

The USGS collected data on 55 VOCs primarily between 1991 and 2002. The team

analyzed water samples before homeowners treated or filtered the water,

which could help reduce VOCs. Many—possibly half of all well users—don't

filter

their water. The wells ranged in depth from 6 to 1,500 feet, with a median

depth of about 140 feet. Of the 2,401 wells studied, 65% had detectable levels

of VOCs, and 1% had levels above the EPA maximum contaminant level for the

compound(s) observed. The most common compounds found were chloroform, toluene,

1,2,4-trimethylbenzene, and perchloroethene.

Factors associated with the presence of VOCs were dissolved oxygen content,

precipitation, the presence of a hazardous waste site within 1 km of the

well, aquifer type, and water temperature. The authors note that identifying

factors associated with VOC occurrence may aid in understanding the sources,

transport, and fate of these compounds in groundwater.

Tina Adler