Nitrate in drinking water, even at safe levels (within 50 mg nitrate/liter of water), increases colorectal cancer (CRC) risk. Scientists assessed drinking water nitrate level exposure in 2.7 million adults and examined 200,000 drinking water analyses from 1978 to 2011 in Denmark. Comparing this data with population-based health registry data, scientists identified 5,944 CRC cases. Analysis of the data showed that exposure to the highest levels of nitrate in drinking water (greater than 9.3 mg/liter of water) increased CRC risk by 15% when compared to those who were exposed to the least amount of nitrate exposure (1.3mg/liter of water). A significant increase in CRC risk was seen starting at nitrate levels as low as 4mg/liter of water. International Journal of Cancer
→Takeaway: This study is consistent with findings from previous international studies, suggesting that nitrate drinking water standards should be more stringent to decrease disease risk. In addition, small private wells and areas where nitrate leaching is higher should be targeted in order to decrease nitrate levels throughout the water system. To decrease your drinking water nitrate exposure use a filter on your drinking water source that removes nitrates.