Estimated probability of arsenic in groundwater from bedrock aquifers in New Hampshire, 2011

Ayotte, Joseph D.; Cahillane, Matthew J.; Hayes, Laura; Robinson, Keith

doi:10.3133/sir20125156

Cited by 11 publications

(14 citation statements)

References 17 publications

(10 reference statements)

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“…Arsenic is present in excess of maximum contaminant levels in domestic water supplies around the world, and can be elevated due to anthropogenic (e.g., agricultural or industrial) or geogenic sources. In New Hampshire, and the larger northeastern United States region of New England, geogenic arsenic is of great concern in drinking water supplies in bedrock aquifers (Ayotte et al ; Moore ; Ayotte et al ; Ayotte et al ; Flanagan et al ; Zheng and Ayotte ; Baris et al ). In New Hampshire, nearly half of the state's population depends on a domestic well water supply, where at least 75 percent comes from drilled bedrock wells and the rest from shallow glacial aquifer wells (U.S. Census Bureau ).…”

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confidence: 99%

“…In New Hampshire, nearly half of the state's population depends on a domestic well water supply, where at least 75 percent comes from drilled bedrock wells and the rest from shallow glacial aquifer wells (U.S. Census Bureau ). As many as 30 percent of these bedrock wells, supplying potentially 120,000 people, may have arsenic concentrations above 10 micrograms per liter (μg/L), the federally and internationally advised limit for safe drinking water (Ayotte et al ; Peters and Blum ; Moore ; Ayotte et al ). Elevated mortality rates for bladder cancer within New England date back to 1950, possibly implicating regionally specific domestic well use (Ayotte et al ) and exposure to naturally occurring inorganic arsenic as a contributor (Baris et al ).…”

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confidence: 99%

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Assessing Models of Arsenic Occurrence in Drinking Water from Bedrock Aquifers in New Hampshire

Andy

Fahnestock

Lombard

et al. 2017

Contemporary Water Research

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Three existing multivariate logistic regression models were assessed using new data to evaluate the capacity of the models to correctly predict the probability of groundwater arsenic concentrations exceeding the threshold values of 1, 5, and 10 micrograms per liter (µg/L) in New Hampshire, USA. A recently released testing dataset includes arsenic concentrations from groundwater samples collected in 2004–2005 from a mix of 367 public‐supply and private domestic wells. The use of this dataset to test three existing logistic regression models demonstrated enhanced overall predictive accuracy for the 5 and 10 μg/L models. Overall accuracies of 54.8, 76.3, and 86.4 percent were reported for the 1, 5, and 10 μg/L models, respectively. The state was divided by counties into northwest and southeast regions. Regional differences in accuracy were identified; models had an average accuracy of 83.1 percent for the counties in the northwest and 63.7 percent in the southeast. This is most likely due to high model specificity in the northwest and regional differences in arsenic occurrence. Though these models have limitations, they allow for arsenic hazard assessment across the region. The introduction of well‐type (public or private), well depth, and casing length as explanatory variables may be appropriate measures to improve model performance. Our findings indicate that the original models generalize to the testing dataset, and should continue to serve as an important vehicle of preventative public health that may be applied to other groundwater contaminants in New Hampshire.

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Assessing Models of Arsenic Occurrence in Drinking Water from Bedrock Aquifers in New Hampshire

Andy

Fahnestock

Lombard

et al. 2017

Contemporary Water Research

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“…This probability of finding arsenic at a location above a given threshold was estimated using multivariate logistic regression models (“probability models”) developed for New Hampshire [28]. The probability models were developed using measurements of arsenic from public and private wells as the dependent (or predicted) variable, and using a variety of geologic, geochemical, hydrologic, and anthropogenic data as the independent variable (predictor) [28-31]. …”

Section: Introductionmentioning

confidence: 99%

“…Threshold values of 1, 5, and 10 μg/L were modeled to identify areas of the State where the probabilities are high for finding low-level (greater than or equal to 1 μg/L) and high-level (greater than or equal to 10 μg/L) arsenic contamination in groundwater. Standard model testing and performance metrics were evaluated and are described in detail elsewhere [28]. …”

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Geospatial association between adverse birth outcomes and arsenic in groundwater in New Hampshire, USA

Shi

Ayotte

Onda

et al. 2014

Environ Geochem Health

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Background There is increasing evidence of the role of arsenic in the etiology of adverse human reproductive outcomes. Since drinking water can be a major source of arsenic to pregnant women, the effect of arsenic exposure through drinking water on human birth may be revealed by a geospatial association between arsenic concentration in groundwater and birth problems, particularly in a region where private wells substantially account for water supply, like New Hampshire, US. Methods We calculated town-level rates of preterm birth and term low birth weight (term LBW) for New Hampshire, using data for 1997-2009 and stratified by maternal age. We smoothed the rates using a locally-weighted averaging method to increase the statistical stability. The town-level groundwater arsenic values are from three GIS data layers generated by the US Geological Survey: probability of local groundwater arsenic concentration > 1 μg/L, probability > 5 μg/L, and probability > 10 μg/L. We calculated Pearson's correlation coefficients (r) between the reproductive outcomes (preterm birth and term LBW) and the arsenic values, at both state and county levels. Results For preterm birth, younger mothers (maternal age < 20) have a statewide r = 0.70 between the rates smoothed with a threshold = 2,000 births and the town mean arsenic level based on the data of probability > 10 μg/L; For older mothers, r = 0.19 when the smoothing threshold = 3,500; A majority of county level r values are positive based on the arsenic data of probability > 10 μg/L. For term LBW, younger mothers (maternal age < 25) have a statewide r = 0.44 between the rates smoothed with a threshold = 3,500 and town minimum arsenic level based on the data of probability > 1 μg/L; For older mothers, r = 0.14 when the rates are smoothed with a threshold = 1,000 births and also adjusted by town median household income in 1999, and the arsenic values are the town minimum based on probability > 10 μg/L. At the county level, for younger mothers positive r values prevail, but for older mothers it is a mix. For both birth problems, the several most populous counties - with 60-80% of the state's population and clustering at the southwest corner of the state – are largely consistent in having a positive r across different smoothing thresholds. Conclusion We found evident spatial associations between the two adverse human reproductive outcomes and groundwater arsenic in New Hampshire, US. However, the degree of associations and their sensitivity to different representations of arsenic level are variable. Generally, preterm birth has a stronger spatial association with groundwater arsenic than term LBW, suggesting an inconsistency in the impact of arsenic on the two reproductive outcomes. For both outcomes, younger maternal age has stronger spatial associations with groundwater arsenic.

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Prediction of elevated groundwater fluoride across India using multi-model approach: insights on the influence of geologic and environmental factors

Sarkar

Mukherjee

Chakraborty

et al. 2022

Environ Sci Pollut Res

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Estimated probability of arsenic in groundwater from bedrock aquifers in New Hampshire, 2011

Cited by 11 publications

References 17 publications

Assessing Models of Arsenic Occurrence in Drinking Water from Bedrock Aquifers in New Hampshire

Assessing Models of Arsenic Occurrence in Drinking Water from Bedrock Aquifers in New Hampshire

Geospatial association between adverse birth outcomes and arsenic in groundwater in New Hampshire, USA

Prediction of elevated groundwater fluoride across India using multi-model approach: insights on the influence of geologic and environmental factors

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