A cross-sectional study of exposure to mercury in schoolchildren living near the eastern seaboard industrial estate of Thailand.

Background: Industrial activity in Thailand's coastal areas has significantly increased mercury concentrations in seawater, causing accumulation through the food chain. Continuous exposure to mercury has been linked to bioaccumulation in living organisms and potential adverse health effects in children.

Methods: Blood samples were collected from 873 schoolchildren aged 6-13 years living in four sites near the eastern seaboard industrial estates of the Gulf of Thailand in 2011. Total mercury level in whole blood (Hg-B) was compared with standard reference values.

Results: Mean (± standard deviation) concentrations of Hg-B from schoolgirls (2.19 ± 0.5 μg/L; n = 405) and schoolboys (2.29 ± 0.3 μg/L; n = 468) did not exceed the regulatory limits of the United States Environmental Protection Agency (US EPA), the German Commission on Human Biological Monitoring (HBM I, II) or Clarke's analysis of drugs and poisons reference values. Nevertheless, 67 children (34 girls and 33 boys) had individual values that exceeded the lowest of these standards (4 μg/L).

Conclusion: The relatively low concentrations of Hg-B detected in this study suggested a relatively low risk for schoolchildren. However, 67 children had elevated mean total Hg-B concentrations, especially in the two sites located nearest the industrial area. This information may serve as an early warning of the potential for pollution to affect children living around industrial areas. Further regular monitoring, including studies assessing the health impact of mercury pollution in this region of Thailand, is to be encouraged.