Well water contaminants and colorectal cancer in North Dakota.

This study aims to identify common contaminants in well water linked to an increase in colorectal cancer (CRC) incidence rates in North Dakota (ND) counties. County-specific incidence rates for CRC were obtained from the ND Statewide Cancer Registry. Corresponding demographic, agricultural, and geophysical data were obtained from population-based sources. Associations between well water contaminants and CRC incidence were examined for 16 counties in ND with complete well water profiles between 1997-2019. Data were analyzed by multiple linear regression. Iron in well water exhibited a significant positive association with CRC incidence (4.75, P = 0.001), and barium exhibited a small, but significant negative association (-0.06907, P = 0.01). Residents in counties in ND with prevalent well water usage contaminated with iron may be at higher risk for CRC.