Impact of chlorination on the incidence of cancers and miscarriages in two different campus communities in India. In India Chlorinated water may halve the risk of cancer compared to untreated water. ?Demonstrates importance of pathogens or reassurance regarding safety of chlorine.

J Environ Sci Eng. 2008 Jul;50(3):175-8. Impact of chlorination on the incidence of cancers and miscarriages in two different campus communities in India. Goel S. SourceDepartment of Civil Engineering, Indian Institute of Technology, Kharagpur, West Bengal, India. sudhagoel@civil.iitkgp.ernet.in Abstract Long-term impacts of drinking chlorinated water on the incidence of cancers and miscarriages were assessed in a population-based cross-sectional study conducted in the two campus communities of IIT Kanpur (IITK) and IIT Kharagpur (IITKgp). IITK has been using untreated groundwater since the community was established in 1963, while IITKgp has been using chlorinated water for more than 30 years. A house-to-house survey was carried out to gather information on residential history, i.e age, education, income, source and extent of treatment of water and health characteristics. Only adults above 20 years of age were included for data analyses. Odds ratios were calculated based on the hypothesis that exposure to chlorinated drinking water may result in a higher incidence of cancers and miscarriages as found in many studies. The odds ratios (OR) in this study were found to be 0.56 (95% CI = 0.16 to 1.62) for cancers and 0.33 (95% CI = 0.19-0.56) for miscarriages. These OR values are not statistically significant indicating the lack of association between cancers or miscarriages and exposure to chlorinated drinking water, and are in agreement with some published epidemiological studies as well. Reciprocal OR values were calculated based on an alternative hypothesis that chlorination actually decreases the risk of cancers and miscarriages. Based on this, the OR values for cancers are 1.77 (95% CI = 0.55 to 5.66) and for miscarriages are 3.07 (95% CI = 1.78 to 5.29). These results show that there is no association between exposure to chlorinated drinking water and cancers while there is significant decrease in the incidence of miscarriages for those exposed to chlorinated drinking water.