In
greater Augusta of central Maine, 53 out of 1093 (4.8%) private
bedrock well water samples from 1534 km2 contained [U]
>30 μg/L, the U.S. Environmental Protection Agency’s
(EPA) Maximum Contaminant Level (MCL) for drinking water; and 226
out of 786 (29%) samples from 1135 km2 showed [Rn] >4,000
pCi/L (148 Bq/L), the U.S. EPA’s Alternative MCL. Groundwater
pH, calcite dissolution and redox condition are factors controlling
the distribution of groundwater U but not Rn due to their divergent
chemical and hydrological properties. Groundwater U is associated
with incompatible elements (S, As, Mo, F, and Cs) in water samples
within granitic intrusions. Elevated [U] and [Rn] are located within
5–10 km distance of granitic intrusions but do not show correlations
with metamorphism at intermediate scales (100−101 km). This spatial association is confirmed by a high-density
sampling (n = 331, 5–40 samples per km2) at local scales (≤10–1 km) and
the statewide sampling (n = 5857, 1 sample per 16
km2) at regional scales (102–103 km). Wells located within 5 km of granitic intrusions are at risk
of containing high levels of [U] and [Rn]. Approximately 48 800–63 900
and 324 000 people in Maine are estimated at risk of exposure
to U (>30 μg/L) and Rn (>4000 pCi/L) in well water, respectively.
In epidemiology research, a list of residences a person has occupied as well as a history of tenants for a residence are useful pieces of information for investigating geographically localized risk factors, environmental exposures, and for analyzing disease clusters. This article reports on a methodology for constructing residential and tenure histories using multi‐year white page phone listings. Residential histories associate a person with a list of addresses of residence and the length of occupancy at each address. Tenure histories document the list of persons occupying a residence along with length of occupancy. These histories were created using fuzzy matching on name address pairs between sequential years. Simulated annual phone listing data were used to develop and test the methodology which was then applied to an actual white page phone listing for a study town in Maine. The approach is applied locally and generates partial local residential and tenure histories that capture local migrations. We see these local history sets as building blocks for constructing more geographically extensive histories over time. Geocoded results were compared against numbers of housing units reported in the 2000 and 2010 US Census to assess the proportion of local residences captured by phone listings.
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