Groundwater quality for 75 domestic wells in Lycoming County, Pennsylvania, 2014

Drinking water health standards comparison and chemical analysis of groundwater for 72 domestic wells in Bradford County, Pennsylvania, 2016

“…Studies in Pike County and Sullivan County indicated few exceedances of the drinking water health standards, and samples that had elevated pH and methane often showed higher concentrations of sodium, lithium, boron, fluoride, and bromide (Senior, 2009(Senior, , 2014Sloto, 2013;. Studies in Wayne County and Lycoming County presented similar results but also included bacteria sampling that indicated exceedances of the drinking water health standards and geochemical modeling that offered further insight into the effect that water-rock reactions, topographic position, and pH have on the regional groundwater chemistry (Senior and others, 2017;Gross and Cravotta, 2017).…”

“…If the notched intervals around the medians for sample subsets do not overlap, the medians are statistically different at the 95-percent confidence interval. An extensive description of the graphical and statistical methods used in this report and the basis for classifications used in the appendix are described in Gross and Cravotta (2017).…”

“…A conceptual hydrogeochemical model that indicates spatial relations among the salinity, water types, redox, and methane sources associated with shallow, intermediate, and deep groundwater flow systems for Bradford and surrounding counties is described in Gross and Cravotta (2017). Most wells constructed for domestic use are completed within the local freshwater-flow system.…”

Evaluation of radon occurrence in groundwater from 16 geologic units in Pennsylvania, 1986–2015, with application to potential radon exposure from groundwater and indoor air

“…Radon concentrations in groundwater have been measured across Pennsylvania by the USGS and are described in various reports, such as those by Lindsey and Ator (1996), Senior (1998), Sloto (2000), Senior (2009), Johnson and others (2011), Chapman and others (2013, , Senior (2014), Sloto (2014), Senior and others (2016), and Gross and Cravotta (2017), for selected counties and regions. Lindsey and Ator (1996) examined radon concentrations in groundwater samples collected from 267 bedrock wells in the Lower Susquehanna and Potomac River Basins, which include a portion of south-central Pennsylvania.…”

“…Similar results were reported for groundwater samples collected in 2014 from 75 wells in Lycoming County, which shares Sullivan County's western boundary; radon concentrations exceeded 300 pCi/L in 67 percent of samples and 4,000 pCi/L in 4 percent of samples. Three samples with radon concentrations greater than 4,000 pCi/L were from geologic units primarily consisting of sandstone (Gross and Cravotta, 2017 (Miles and Whitfield, 2001) was used for aggregating most analyses, a geographic information system (GIS) was used to remove two records with spatial coordinates that did not fall within the boundaries designated by the geology dataset. Nevertheless, even geocoding precision scores equal to 100 can be inaccurate by as much as 700 feet, which poses minor classification limitations in a small number of cases (Gross, 2013).…”