October 9, 2014
Increased levels of metals such as cadmium, arsenic, lead and manganese in North Carolina are present in private well water, and some may be linked to defects in children, a new UNC Gillings School of Global Public Health study has found.
In a research article published Sept. 15 by BioMed Central Public Health, researchers at the Gillings School and colleagues from the N.C. Birth Defects Monitoring Program (NCBDMP) found associations between statewide levels of metals in wells and detrimental health outcomes.
The study reported that drinking metal-contaminated water may be a public health concern in North Carolina. In addition to causing heart defects, exposure to these metals can lead to spontaneous abortion, stillbirth, low birth weight and impaired neural development in infants.
Senior author on the study was Rebecca Fry PhD, associate professor of environmental sciences and engineering and deputy director of the UNC Superfund Research Program, joined by Gillings School colleagues Alison P. Sanders PhD, a former graduate student in the department of environmental sciences and engineering and first author of the study; Tania A. Desrosiers, PhD, research specialist, and Andrew F. Olshan, PhD, Barbara Sorenson Hulka Distinguished Professor in Cancer Epidemiology and chair of the Department of Epidemiology; Joshua L. Warren, PhD, postdoctoral fellow, and Amy H. Herring, ScD, professor in the Department of Boostatistics; and Robert E. Meyer, PhD, adjunct professor in the Department of Maternal and Child Health and director of the NCBDMP.
Diet and drinking water are common sources of metal exposure, and 2.3 million North Carolina residents get their drinking water from private wells. The quality of these wells is not federally monitored, and metal levels in private wells are not regulated by the state. Testing of private well water for contaminants also is not required at the state or federal level.
The research included census tracts from groups across the state. Private well water data from between 11,000 and 47,000 wells was provided by the N.C. Department of Health and Human Services. The research examined private well water and found levels of arsenic, cadmium, manganese and lead. Using a semi-ecologic study design, the researchers were able to estimate the association between metal levels and specific birth defect types.
The study identified three findings of note, including that levels of metals are elevated in private wells across the state, with some metals such as arsenic and manganese co-existing in the water; people living in residences with high levels of exposure to manganese had higher prevalence of heart defects; and populations in arsenic- and manganese-exposed areas corresponded with a prevalence of heart defects.
The study supports previous evidence of an association between metal exposure and heart defects, and the report urges that these relationships be prioritized for future studies. Further research is needed to better understand the biological and genomic mechanisms that underlie metal-birth defect associations.