U.S. Geological Survey
U.S. Department of the Interior
News Release
Date: January 2, 2008
Contact: Joseph Ayotte 603-226-7810 jayotte@xxxxxxxx
603-568-0321 (cell)
Keith
Robinson 603-226-7807
kwrobins@xxxxxxxx
___________________________________________________________________________
Gasoline Additive MTBE Widespread
in New Hampshire’s Ground Water
The gasoline additive methyl tert-butyl
ether (MTBE) is widespread in New Hampshire’s ground water, particularly
in four counties -- Rockingham, Strafford, Hillsborough and Merrimack.
Ground water from these counties was more likely to contain MTBE
than were samples from the rest of the state. Across the state, however,
the MTBE concentrations were significantly below the state drinking water
limit and the federal drinking water advisory. These findings were
released today by the U.S. Geological Survey.
In Rockingham, Strafford, Hillsborough
and Merrimack counties, cleaner-burning reformulated gasoline was mandated
in 1995, but not in other counties in the state.
“In the four counties using reformulated
gasoline, we found MTBE at or above 0.2 parts per billion (ppb) in 30 percent
of public supply wells and in 17 percent of the private homeowner wells,”
said USGS hydrologist, Joseph Ayotte, lead author of the study.
“One in every three wells tested
in Rockingham County had MTBE. In the most densely populated areas
of the county, one in two wells tested contained MTBE,” said Ayotte. “We
also found that more than 70 percent of the water tested from wells serving
mobile home communities in the state had MTBE.
“While levels are mostly very
low, the study shows that MTBE occurs in ground waters throughout the state.
A low analytical measurement of 0.2 ppb enabled us to characterize MTBE
contamination throughout the state,” said Ayotte.
For this study, scientists sampled
more than 800 wells throughout New Hampshire in 2005 and 2006. Statewide,
scientists detected MTBE in untreated ground water from 18 percent of the
public supply wells and 9 percent of the private wells tested. Despite
the prevalence of MTBE in water samples from wells, most concentrations
measured were less than 1 ppb. About two percent of the public and
one percent of the private wells sampled had levels that were greater than
the state of New Hampshire health-based limit of 13 ppb.
Done in cooperation with the NH
Department of Environmental Services, this study is the most comprehensive
examination to date of MTBE in water from public and private wells in the
state.
“This study provides valuable
information for tracking this state-wide water contamination issue,” said
Thomas Burack, Commissioner, and New Hampshire Department of Environmental
Services. “We are now actively monitoring many public drinking water supplies
for MTBE. I believe we need to continue to study MTBE in the waters
of New Hampshire to determine how best to address an issue that is important
to the health and welfare of the entire state’s population and its environment.”
Nationwide, starting in 1979, MTBE
was added to gasoline as an octane booster to replace lead. In 1995,
under the Clean Air Act, cleaner-burning reformulated gasoline was required
for areas with the worst smog. In New Hampshire, the only areas that were
required to use reformulated gasoline were Rockingham, Strafford, Hillsborough
and Merrimack counties. Reformulated gasoline in New Hampshire had about
11 percent MTBE by volume. In January 2007, New Hampshire banned
MTBE use in gasoline.
No data exist on the human health
effects of ingesting MTBE in drinking water, although some studies have
generated concern about possible cancerous and non-cancerous effects. No
federal regulatory standards have been set for MTBE, but an advisory of
20-40 ppb has been issued by the U.S. Environmental Protection Agency.
Much of New Hampshire’s public
and private water supplies are derived from wells drilled into surficial
and bedrock aquifers, where ground water can travel slowly. This,
in addition to factors like New Hampshire’s unique geologic formations
and fractured-rock aquifers, makes it uncertain how long MTBE will persist
in the state’s ground water.
The USGS report, “Methyl tert-Butyl
Ether (MTBE) in Public and Private Wells in New Hampshire: Occurrence,
Factors, and Possible Implications,” is published in the journal Environmental
Science & Technology. The
abstract can be viewed at http://pubs.acs.org/journals/esthag/index.html
.
Information on previous studies
of MTBE in water supplies in New Hampshire can also be found at:
USGS Water Resources
of New Hampshire and Vermont
http://nh.water.usgs.gov/projects/mtbe.htm
New Hampshire
Department of Environmental Services
http://www.des.state.nh.us/factsheets/ws/ws-3-19.htm
U.S. Environmental
Protection Agency
http://www.epa.gov/waterscience/criteria/drinking/mtbe.html
USGS provides science for a changing
world. For more information, visit www.usgs.gov.
Subscribe to USGS News Releases
via our electronic
mailing list or RSS
feed.
***www.usgs.gov***
Diane Noserale
Media Relations, Eastern Region
U.S. Geological Survey
150 National Center
Reston, VA 20192
phone: 703-648-4333
fax: 703-648-4588
