The changes of essential trace elements in residents from an e-waste site and the relationships between elements and hormones of the hypothalamic-pituitary-thyroid (HPT) axis

The heavy metals pollution and related health issues were widely reported in e-waste sites, while the impacts of e-waste exposure on the essential trace elements have been neglected. The aim of this study was focused on the internal Cu, Fe, Mn and Zn levels in the residents from an e-waste site and the potential endocrine disrupting effects of these essential trace elements on the hypothalamic-pituitary-thyroid (HPT) axis. This was a crosssectional study that 87 subjects were recruited from the e-waste site and 81 from the reference site. The results indicated that the e-waste exposed group had significantly lower Fe, Mn level when compared with the reference group (p < 0.05). Cu and Zn were also lower in the exposed group but the differences were not statistically significant. The exposed group had significantly higher TSH level and Fe was significantly associated with TSH in the females (beta (95% CI): - 1.892 (-3.309, -0.475), p = 0.009), rather than in males or all subjects. The exposed group also showed oxidative stress which was indicated by the increased concentrations of MDA and 8-iso-PG. It was further indicated the elevated MDA was mediated by the increase of TSH in the females but not directly related to Fe. In conclusion, the e-waste exposed group showed a decrease of essential trace elements, an increase of TSH and oxidative stress. The decreased Fe was related to the elevated TSH in the females, which further indirectly mediated the increase of oxidative stress. The results suggested that the internal exposure levels and the potential health effects of the essential trace elements in populations from e-waste sites should be of more concern. And the women might be more vulnerable and they need more protection to against the adverse health effects from e-waste.

Automated summary

The study focused on investigating the levels of essential trace elements copper, iron, manganese, and zinc in residents from e-waste sites, as well as the potential endocrine effects on the HPT axis. Results showed significantly lower levels of iron and manganese in the e-waste exposed group, along with higher TSH levels. Oxidative stress was also observed, with MDA and 8-iso-PG concentrations being increased and correlated with higher TSH levels.