Arsenic in North Carolina: Public Health Implications

Abstract

Arsenic is a known human carcinogen and relevant environmental contaminant in drinking water systems. We set out to comprehensively examine statewide arsenic trends and identify areas of public health concern. Specifically, arsenic trends in North Carolina private wells were evaluated over an eleven-year period using the North Carolina Department of Health and Human Services (NCDHHS) database for private domestic well waters. We geocoded over 63,000 domestic well measurements by applying a novel geocoding algorithm and error validation scheme. Arsenic measurements and geographical coordinates for database entries were mapped using Geographic Information System (GIS) techniques. Furthermore, we employed a Bayesian Maximum Entropy (BME) geostatistical framework, which accounts for geocoding error to better estimate arsenic values across the state and identify trends for unmonitored locations. Of the approximately 63,000 monitored wells, 7,712 showed detectable arsenic concentrations that ranged between 1 and 806 μg/L. Additionally, 1,436 well samples exceeded the EPA drinking water standard. We reveal counties of concern and demonstrate a historical pattern of elevated arsenic in some counties, particularly those located along the Carolina terrane (Carolina slate belt). We analyzed these data in the context of populations using private well water and identify counties for targeted monitoring, such as Stanly and Union Counties. By spatiotemporally mapping these data, our BME estimate revealed arsenic trends at unmonitored locations within counties and better predicted well concentrations when compared to the classical kriging method. This study reveals relevant information on the location of arsenic-contaminated private domestic wells in North Carolina and indicates potential areas at increased risk for adverse health outcomes.

Long-term health consequences of prenatal arsenic exposure: links to the genome and the epigenome

“…While the World Health Organization (WHO) established a recommended limit of 10 μg/L (WHO 2006) for arsenic in drinking water, levels that exceed this value have been detected in drinking water sources in areas throughout the world, including but not limited to Bangladesh, India, Mexico, the United States, and Vietnam (ATSDR 2007). New locations with drinking water contaminated with iAs continue to be identified as highlighted by our recent identification of elevated iAs in private wells in North Carolina (Ayotte, Montgomery et al 2003, Camacho, Gutiérrez et al 2011, Sanders, Messier et al 2012). These elevated levels are of concern as iAs is a known carcinogen with target sites including the liver, lung, prostate, skin, and urinary bladder (NTP 2011).…”

Assessment of outdoor radiofrequency electromagnetic field exposure through hotspot localization using kriging-based sequential sampling

“…It takes into account the spatial structure of the interpolated variable (here, the electric-field strength), determines the best estimator of the variable (the error is minimized at all points), and it gives us information about the accuracy of the interpolation, by calculating an error estimate, called kriging variance (Matheron, 1963). Because of this, kriging is an often used interpolation technique in environmental research (e.g., Liu and Rossini, 1996;Paniagua et al, 2013;Sanders et al, 2012;Zirschky, 1985). The kriging variance can be used to quantify the model uncertainty, and to assist the sample search strategy in identifying potentially interesting regions in the study area based on a given condition.…”

Arsenic alters transcriptional responses to Pseudomonas aeruginosa infection and decreases antimicrobial defense of human airway epithelial cells

“…Polarized HBE cells were exposed to 0, 5, 10 or 50 µg/L total arsenic in basolateral Bronchialife media for 6 days, with media replaced every other day. Arsenic exposure concentrations were chosen to reflect concentrations measured in serum of US and Bangladeshi populations drinking water with 10–600 µg/L arsenic (Hall et al, 2007; Sanders et al, 2012). Exposures were conducted with a mixture representative of arsenic speciation in human serum; 25% iAs III , 25% MMA III and 50% DMA V as described previously (Hall et al, 2007; Notch et al, 2015).…”