Health risk of childhood exposure to PCDD/Fs emitted from a municipal waste incinerator in Zhejiang, China.

This study aimed to evaluate the body burdens of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and their associated health impacts toward school-age children living near a municipal waste incinerator (MWI). A total of 82 children from the exposure area and 49 from the control area were recruited. We measured blood PCDD/F levels, conducted comet assays, calculated the percentage of 5-methylcytosine (%5-mC) and 5-hydroxymethylcytosine (%5-hmC), performed flow cytometry, measured hormonal levels, and analyzed hematological parameters. We also examined 17 congeners of PCDD/Fs in environmental samples, namely, eggs, rice, water, soil, and PM2.5. The mean blood levels of ΣPCDD/Fs and TEQ-ΣPCDD/Fs were statistically higher in the exposure group than in the control group (3.40 vs. 2.77 pg/g wet weight and 0.40 vs. 0.28 pg WHO-TEQ/g wet weight, respectively; p < 0.05). By contrast, the %5-mC and %5-hmC levels were statistically lower in the exposure group than in the control group (1.15% vs. 4.66% and 0.22% vs. 0.30%, respectively; p < 0.01), whereas the mean % tail DNA was statistically higher in the exposure group than in the control group (10.10% vs. 8.28%, p < 0.01). The mean blood levels of ΣPCDD/Fs and TEQ-ΣPCDD/Fs were both negatively correlated with %5-mC (r = -0.245 and r = -0.217, respectively; p < 0.01) but not with %5-hmC and % tail DNA (p > 0.05). Furthermore, the mean ΣPCDD/F levels in eggs and soil obtained from the exposure area were statistically higher than those of the samples obtained from the control area (31.08 vs. 4.32 pg/g dry weight and 1026.04 vs. 674.97 pg/g dry weight, respectively). In conclusion, children living near the MWI may suffer genetic and epigenetic modifications, such as DNA damage or global DNA hypomethylation due to the MWI-emitted PCDD/Fs and other contaminants.