[Study on genomic stability of male workers in an e-waste dismantling area in Tianjin]

Objective: To study on the genomic stability of male workers engaged in e-waste dismantling area in Tianjin. Methods: In 2016, an e-waste dismantling area in Tianjin and an area 50 km away from the e-waste dismantling area (no e-waste or other chemical, industrial and agricultural pollution nearby) were selected as the study area and the reference area. Male residents of the study area and male farmers who planted vegetables, fruits, and crops in the reference area were selected as the exposed and reference group by using the convenient sampling method. The exposed group included 146 workers who engaged in e-waste recycling work more than 1 year. The reference group included 121 farmers who never engaged in e-waste recycling work. Questionnaires were used to collect information of all subjects. The semen and peripheral blood were also collected. Trace elements and polychlorinated biphenyl concentration in blood were detected. DNA damage in peripheral blood and sperm was detected, and gene expression was analyzed. DNA damage was assessed using tail DNA% (TDNA%), tail moment (TM) and olive tail moment (OTM) of comet assay. Results: The ages of the exposed group and the reference group were (33.6±12.1) and (33.9±11.9) years old, respectively. The proportions of subjects with exposure time of ≤3, 4-6, ≥7 years were 43% (63 cases), 26% (53 cases) and 21% (30 cases), respectively. The Pb and polychlorinated biphenyl(PCB) concentrations in the exposed group [(90.4±15.3) μg/ml and (101±30) ng/ml, respectively] were higher than those in the reference group [Pb and PCB concentrations were (60.2±8.9) μg/ml, and (2.5±1.4) ng/ml, respectively (both P values <0.05)]. The TDNA%, TM and OTM of peripheral blood and sperm in the exposed group were 5.9%±0.3% and 2.6%±0.90%, 0.93±0.16 and 0.51±0.20, 0.82±0.09 and 0.56±0.07, respectively, which were all higher than those in the reference group [TDNA%, TM and OTM of peripheral blood and sperm were 1.8%±0.2% and 1.9%±0.2%, 0.21±0.04 and 0.32±0.10, 0.19±0.03 and 0.20±0.08, respectively (all P values <0.001)]. The results of gene expression showed that 20 differentially expressed genes, including 13 up-regulated genes and 7 down-regulated genes, were detected in the exposed group compared with the reference group. Conclusion: There are obvious DNA damage and DNA repair gene disorder in male workers of an e-waste dismantling area in Tianjin. The current operation mode brings potential health risks to workers.