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 In
early 2004 you may have noticed water well drilling taking
place within Carmichael Water District’s service area,
especially near Grant Avenue, Hollister Avenue and Marshall
Avenue. The purpose of the water well drilling is to monitor
for potential contaminants, such as N-nitrosodimethylamine
(NDMA).
During the last quarter of 2003, Aerojet drilled a test well
located in Rancho Cordova at Rossmoor Bar. Rossmoor Bar is
located in the American River Parkway directly across the
river from the end of Landis Avenue. Samples from the test
well detected the presence of NDMA in the range of 200-300
mg/L (milligrams per liter or parts per million). Because
of these high levels, Aerojet has been ordered to drill additional
monitoring wells within the Carmichael Water District’s
service area. The purpose of these monitoring wells is to
determine if NDMA or any other contaminant has crossed under
the American River into Carmichael.
NDMA is a contaminant of recent concern by drinking water
regulators because of its discovery in contaminated groundwater
supplies. NDMA is identified as a carcinogen by Title 22,
California Code of Regulations (22CCR), Section 12000 pursuant
to the Safe Drinking Water and Toxic Enforcement Act of 1986
(Proposition 65), Health and Safety Code Section 25249.5,
et, . In April 1998, California Department of Health Services
(DHS) established a drinking water action level (AL) for NDMA
of 2 ng/L (nano grams per liter or parts per trillion).
The United States Environmental Protection Agency (EPA) also
evaluated the health effects of NDMA and classifies it as
a probable human carcinogen. Following the initial northern
California findings in February 1998, DHS informed affected
Drinking Water Utilities that the Office of Environmental
Health Hazard Assessment (OEHHA) had evaluated NDMA’s
cancer risk. OEHHA established in 22CCR 12705(b)(1) a 0.04
ug/l per day exposure level for NDMA for “no significant
risk”, for purposes of Proposition 65’s warning
requirements and discharge prohibition. This equates to 0.02
ug/L (parts per billion) in drinking water, using a 2-liter
daily consumption for 70 years. This corresponds to a theoretical
risk of up to one excess case of cancer per million people
drinking 2 liters of water per day for a 70-year lifetime.
Since 2000, Carmichael
Water District has tested all ground water wells and surface
water supply for NDMA and to date has had zero detections.
In 2001, Carmichael Water District completed it new Surface
Water Treatment. The new plant has the capacity to deliver
up to 90% of the District’s water supply needs. The
District will continue to monitor the results from Aerojet’s
monitoring and to conduct its own testing for NDMA in all
its drinking water supplies.
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