Increased mortality odds ratio of male liver cancer in a community contaminated by chlorinated hydrocarbons in groundwater

Abstract

Aims: To investigate the association between cancer mortality risk and exposure to chlorinated hydrocarbons in groundwater of a downstream community near a contaminated site.

Methods: Death certificates inclusive for the years 1966–97 were collected from two villages in the vicinity of an electronics factory operated between 1970 and 1992. These two villages were classified into the downstream (exposed) village and the upstream (unexposed) according to groundwater flow direction. Exposure classification was validated by the contaminant levels in 49 residential wells measured with gas chromatography/mass spectrometry. Mortality odds ratios (MORs) for cancer were calculated with cardiovascular-cerebrovascular diseases as the reference diseases. Multiple logistic regressions were performed to estimate the effects of exposure and period after adjustment for age.

Results: Increased MORs were observed among males for all cancer, and liver cancer for the periods after 10 years of latency, namely, 1980–89, and 1990–97. Adjusted MOR for male liver cancer was 2.57 (95% confidence interval 1.21 to 5.46) with a significant linear trend for the period effect.

Conclusion: The results suggest a link between exposure to chlorinated hydrocarbons and male liver cancer risk. However, the conclusion is limited by lack of individual information on groundwater exposure and potential confounding factors.