Academic journal article Journal of Environmental Health

Elevated Arsenic in Private Wells of Cerro Gordo County, Iowa: Causes and Policy Changes

Academic journal article Journal of Environmental Health

Elevated Arsenic in Private Wells of Cerro Gordo County, Iowa: Causes and Policy Changes

Article excerpt

Introduction

One of the most challenging environmental health problems today, known to affect millions of people worldwide, is arsenic-contaminated drinking water (Amini et al., 2008; Bhattacharya et al., 2007; Nordstrom, 2002; Smith, Lopipero, Bates, & Steinmaus, 2002). The World Health Organization (WHO, 2010, 2016) guideline for arsenic in drinking water is 10 micrograms per liter (pg/L). The U.S. Environmental Protection Agency has also set the maximum contaminant level (MCL) for arsenic at 10 pg/L (U.S. EPA, 2002). U.S. EPA regulates public water systems, but does not have the authority to regulate drinking water in private wells (U.S. EPA, 2016). Thus, many private wells are not tested for arsenic.

A complete literature review on arsenic contamination in groundwater and the resulting health effects is beyond the scope of this article. There are, however, some excellent review summaries on arsenic contamination in groundwater (Ahuja, 2008; Khan, Sakauchi, Sonoda, Washio, & Mori, 2003; Mukherjee et al., 2006; Ravenscroft, Brammer, & Richards, 2009; Welch, Lico, & Hughes, 1988). In addition, organic arsenic is not readily eliminated by the body, compounding chronic negative health effects (Bates, Smith, & Hopenhayn-Rich, 1992; Flora, 2015). In particular, chronic arsenic exposure can result in skin lesions, keratosis, peripheral neuropathy, gastrointestinal symptoms, renal system effects, high blood pressure, reproductive problems, cardiovascular disease, and cancer (Bhattacharya et al., 2007; Chen et al., 2009; Kapaj, Peterson, Liber, & Bhattacharya, 2006; Navas-Acien et al., 2005; Navas-Acien, Silbergeld, Pastor-Barriuso, & Guallar, 2008; Ng, Wang, & Shraim, 2003; Nordstrom, 2002; Smedley & Kinniburgh, 2002; WHO, 2010, 2016).

Arsenic in drinking water was initially discovered in Cerro Gordo County in the 1990s, with the extent of the problem becoming better known in recent years. Rural populations in the Midwest might be at higher risk, as they often tend to be less transient and families drink water from the same well source for many years. Arsenic in Iowa wells has been relatively unstudied (Schnoebelen & Walsh, 2014a, 2014b). The Iowa Statewide Rural Well Water Survey Phase 2 in 2005, however, showed that arsenic was present in 47% of the wells tested, with elevated arsenic levels found in 33 counties, including Cerro Gordo County (Center for Health Effects of Environmental Contamination, 2017).

Most private wells in the study area are open at depths between 100-400 feet and utilize the 1) Devonian Lime Creek Formation (Lime Creek Aquifer), the upper aquifer or 2) the Devonian Cedar Valley Group (Cedar Valley Aquifer), the lower aquifer. The limestone and dolostone formations of the aquifers are accompanied by minor shale deposits and pyrite (Iowa Department of Natural Resources [IDNR], 2013; Prior, Boekhoff, Howes, Libra, & VanDorpe, 2003). The Cedar Valley Aquifer exceeds 350 feet in thickness in places, is deeper, contains less shale, and yields more water than the Lime Creek Aquifer.

This 5-year study was funded through the Environmental Health Specialist Network (EHS-Net) Water Program at the Centers for Disease Control and Prevention (CDC) beginning in 2010 (CDC, 2014a, 2014b). The partners involved included the University of Iowa, Iowa Department of Natural Resources (IDNR), Iowa State Hygienic Laboratory (SHL), and Shawver Well Company. The diverse team had experts in public health and communication, analytical chemistry, geochemical modeling, geology, and well drilling.

The study objectives for Cerro Gordo County were to identify the source, mobilization, and distribution of arsenic in groundwater. In addition, the study team embarked on a strong education and outreach campaign to educate and inform private wells owners throughout the study.

Methods

Well Selection

Potential wells were selected using data from the IDNR GeoSAM database (IDNR, 2017). …

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