What's in Your Water? Groundwater Contamination of Private Wells in North Carolina An integrative investigation of the sources and effects of groundwater contamination for local communities and homeowners in North Carolina • Avner Vengosh, Erika Weinthal, Lori Snyder Bennear, Emily Klein, and Marie Lynn Miranda: Nicholas School of Environment and Earth Sciences, Duke University • Mark Wiesner: Pratt School of Engineering, Duke University • Hope Taylor-Guevara: Clean Water for North Carolina • Ted Campbell , Rick Bolich, North Carolina Dept. of Environment and Natural Resources, Division of Water Quality - Groundwater Section An integrative investigation of the sources and effects of groundwater contamination for local communities and homeowners in North Carolina Awareness, Willingness- Mobilization to-pay (Socioeconomic) (geochemistry) Occurrence (GIS) Public policy, Remediation Legislation (technology) Outreach USDA project 2006-03956 Statement of the Problem • More than two million residents in North Carolina use groundwater as a sole source for drinking water. Increase in population is associated with drilling new wells (5,000 to 6,000 per year). • In several areas, the levels of natural contaminants, radon, arsenic, and radium exceed drinking water regulations. • Wells of private homeowners are not regulated. Major hydrogeological units of North Carolina Hot spots Typical private well and geology in the Piedmont, NC Regolith saprolite Casing Transition zone …igneous, metasedimentary, Open hole and metavolcanic Fractured rock hole rocks (NCGS data) 2005, 103 private wells Detailed above Radon Formations 20,000 pCi/L (60X proposed MCL) Radon: 300 to 4000 pCi/L Radon: above 4000 pCi/L granite gneiss Ordivician, 438 M , interlayered w/ biotite augens granodiorite Henderson Devonian, 390 M Gneiss Cambrian, 500 M Meta-igneous rock Metasedimentary rock Ted Campbell, NC Division of Water Quality, Aquifer Protection Section Slate Belt and Raleigh Belt 60 wells above 4,000 pCi/L Metamorphosed Guilford granitic rock Franklin Felsic and mafic igneous 27 wells above and meta- Orange 10,000 pCi/L igneous rock Wake Granitic Median = 735 pCi/L Raleigh plutons Median = 586 pCi/L gneiss Max = 6,300 pCi/L Max = 4,229 pCi/L (70 private wells) (42 wells) (Spruill and others, 1997) Median = 2800 pCi/L (Orange Co. staff, 1997) Max = 32,000 pCi/L (305 private wells - Phase I & II) Meta-igneous rock (Cornell and others, 2005) (Bolich and Stoddard, 2004) Ted Campbell, NC Division of Water Quality, Aquifer Protection Section Radium violations (>5 pCi/L) in public water systems Modified after Menetrez and Watson, 1983. Natural radioactivity in North Carolina groundwater supplies. University of North Carolina, Water Resources Research Institution, Report 208, 30p. Distribution of radium in groundwater in Wake County Distribution of Arsenic in Groundwater in North Carolina High-arsenic Groundwater in the Slate Belt Distribution of natural contaminants in groundwater of North Carolina Health effects of arsenic radium, and radon • Epidemiological studies have shown that long-term utilization of drinking water with arsenic and radium levels exceeding the EPA MCL standards is associated with higher frequencies of lung and skin cancer (for arsenic) and leukemia and bone cancer (for radium). • High radon in domestic waters could increase the exposure of users to airborne radon due to degassing of radon from showers and other water utilities in the house. High level of airborne radon is associated with higher frequency of lung cancer. The Piedmont Geology (USGS data) How to protect North Carolina’s private wells • House Bill 2873 Safe Drinking Water/Private Wells: From 2008 all 100 counties establish permitting and inspection programs for new wells. Newly constructed private drinking water wells will be tested for inorganic contaminants (e.g.,arsenic, barium, cadmium, lead, iron) and bacterial indicators. • Emergency Drinking Water Fund as part House Bill 2884: Providing funding to notify well users within 1,500 feet of known contaminated sites and assistance with testing • Outreach, education - is that enough?