Groundwater arsenic concentrations and cancer incidence rates: A regional comparison in Oregon

Arsenic contamination of groundwater is a global issue with national implications. Chronic exposure to arsenic in drinking water has been linked to both carcinogenic and non-carcinogenic health outcomes. The purpose of this study was to determine if there is a spatial relationship between groundwater arsenic concentrations and cancer incidences within two regions of Oregon. The objectives of this study were to: (1) determine if there is a spatial relationship between arsenic concentrations in the Willamette Valley and Southeast Oregon and incidence rates of bladder, liver, lung, and kidney cancers; (2) contribute to the Centers for Disease Control and Prevention's development of the Environmental Public Health Tracking network by using secondary data to investigate linkages of arsenic in groundwater and associated health effects; and (3) serve as an exploratory tool for identifying a public health concern that can be followed up with comprehensive analytical studies of the region. The study used four secondary data sets: Cancer data from the Oregon State Cancer Registry; community water system arsenic data from the Oregon Department of Human Services Drinking Water Program; groundwater arsenic data from the U.S. Geological Survey National Water Inventory System; and population data from the U.S. Census Bureau. Data were analyzed for statistical and spatial analyses using SAS and ArcGIS. Preliminary results indicate several significant differences of risk between population and arsenic concentration intervals. However, the inherent limitations of secondary data have produced unexpected results. Maps created to illustrate the extent of the environmental hazard have also provided interesting results.