Basis for decision
There is no indication that people have been in contact with
concentrations of lead or a toxic form of chromium (hexavalent
chromium) in their private drinking water wells. Many people in the
area have in the past and currently get their drinking water from private
wells. Studies of groundwater flow in the area of the CTS site indicate
that groundwater located at different depths are inter-connected and
have been used as regional drinking water sources.
Lead in groundwater was found at concentrations greater than the
health guideline value referenced by the N.C. Department of Health
and Human Services (DHHS) for private well water supplies. It has not
been confirmed that the groundwater with the elevated lead has been
used, or will be used, as a drinking water source.
Elevated levels of chromium have been identified in groundwater in the
area of the CTS property. If the chromium is present as substantial
concentrations of hexavalent chromium, and the waters have been, or
maybe used as a drinking water source, adverse non-cancer and cancer
health effects could result from long-term ingestion.
Conclusion 3
The DPH concludes that other groundwater contaminants,
including the volatile organic compound (VOC) trichloroethylene
(TCE) and vinyl chloride, are not expected to harm people’s health.
Basis for decision
There is no indication that people have been drinking water that
contains VOC contaminants observed in the groundwater samples. The
concentrations of TCE and other contaminants related to the CTS site
and detected in groundwater beyond the property (off-site) were lower
than the levels expected to harm people’s health.
Vinyl chloride was found in groundwater on the CTS property, but not
off-site. Long-term ingestion of vinyl chloride at the concentration
observed in the on-site groundwater could result in both non-cancer
harm to people’s health and a moderate cancer risk. There is no
potential for health effects if the vinyl chloride does not travel off-site
and people are not exposed.
The DPH concludes that the residents using a private well
identified in 1999 as contaminated with trichloroethylene (TCE),
for possibly as long as 11 years, could have been harmed by
drinking the water or breathing TCE escaping from the water to
the household air.
Persons using two spring private wells serving one home until
approximately 1994, and serving two other homes until 1999, could
have been harmed by drinking the water or breathing TCE
escaping from the water to the household air.
TCE contamination was identified in three private wells serving three
homes in July 1999 and the wells were disconnected. It is not known
when the contamination first appeared in the well water, or what the
range of TCE concentrations were over the time the well was being
used. Some of the health issues reported by family members include
those that have been associated with TCE contact. An increased cancer
risk is indicated if the long-term occupants of the residence were in
contact with TCE concentrations similar to those in the single well
water sample collected in 1999.
Drinking water contaminated with TCE and breathing TCE volatilized
from the drinking water supply over many years in large amounts may
cause adverse health effects. These effects include increased risk of
kidney or liver cancer; dizziness, lung irritation, impaired heart
function; and nerve, kidney or liver damage. Reproductive effects such
as impaired fetal growth or decreased fertility may also result. There
may be an increased risk of birth defects or leukemia to children of
women exposed during pregnancy.
Conclusion 5
The DPH N.C. Central Cancer Registry (CCR) determined that
cancer rates for the population living in a 1-mile radius around the
CTS property were not elevated.
Basis for decision
The CCR studied the number of cancers reported by health care
providers in the area surrounding the CTS site to the expected number
of cases in the same time period. The study focused on the types of
cancers linked with TCE contact: liver cancer, renal cancer, and non-
Hodgkin lymphoma. The results of the investigation indicate that the
observed numbers of cases of these cancers fall within the expected
range, and there is no evidence of a clustering of cancer cases in the
study area.
The cancer evaluation is limited by the small population size of the
study area and the availability of cancer records only since 1990.
Because of the long latency period of most cancers the evaluation is
also limited by the use of a person’s address at the time of diagnosis
rather than the ability to identify if and where the critical exposure that
led to cancer development took place.
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