Epidemiological Study on Health Risk Assessment of Exposure to PM2.5-Bound Toxic Metals in the Industrial Metropolitan of Rayong, Thailand

The concentrations of PM2.5 and metallic elements were measured in Rayong during the dry season (November 2021 to April 2022). The mean PM2.5 concentration was 20.1 +/- 10.9 mu g/m(3) (4.9-52.3 mu g/m(3)). Moreover, the percentages of days when those PM2.5 concentrations exceeded the daily WHO and US-EPA NAAQS limit were 56.8% and 10.2%, respectively. However, the levels did not exceed 50 mu g/m(3), which is the limit of the 24 h standard defined by the PCD in Thailand. The dominant heavy metals and elements in PM2.5 samples were Cr, Cu, Fe, Mn, Pb, V, and Zn, which constituted 70%. In Rayong, the PCA results showed that industrial emissions (Cd, Cu, Fe, Mn, Pb, and Zn) and traffic emissions (As, Cd, Cr, K, and Ni) were the major sources of PM2.5-bound heavy metals. Exposure to toxic metals in PM2.5 through the inhalation pathway in Rayong obviously entails a high potential risk of cancer (>10(-4)) based on the total lung cancer risk (TCRinh). It was found that the TCRinh values of Cr for combined age groups were higher than 10(-6), which implies a high cancer risk in Rayong.