An estimation of the health impact of groundwater pollution caused by dumping of chlorinated solvents

BackgroundHazardous waste sites are major environmental concerns, but few studies have quantified their expected utility loss on health.ObjectivesTo evaluate the health impact of groundwater pollution by an electronics manufacturing factory, we conducted a health risk assessment based on expected utility loss from liver cancer.MethodsBased on measurements of major pollutants, we estimated the likelihood of developing liver cancer after exposure to groundwater contamination. All patients with liver cancer between 1990 and 2005 in the Taiwan Cancer Registry were followed through 2007 using the National Mortality Registry to obtain survival function. Quality of life was assessed with two cross-sectional surveys, one employing the standard gamble method, and the other using the EQ-5D instrument. Quality-adjusted life expectancy (QALE) was estimated by multiplying the utility values with survival function under the unit of quality-adjusted life year (QALY). The difference of QALE between the cancer cohort and the age- and gender-matched reference population was calculated to represent the utility loss due to liver cancer.ResultsA total of 94,144 patients with liver cancer were identified. The average utility loss to development of liver cancer was 17.5 QALYs. Based on toxicological approach, we estimated that groundwater pollution caused 1.7 extra cases of liver cancer, with an overall loss of 29.8 QALYs. Based on epidemiological approach, the expected annual excess number of liver cancer would be 3.65, which would have been accumulated through the years, had the pollution not mitigated.ConclusionsWe demonstrated a practical approach for comparative health risk assessment using QALY as the common unit. This approach can be used for policy decisions based on possible health risks.