Workers exposed to lead at a battery recycling plant in Mexico: Blood lead levels; DNA damage and repair in blood cells (comet assay).

Abstract

Occupational exposure is a problem that needs to be understood to implement action that prevent diseases. In this cross-sectional study, we monitored the total (116) workers at a battery recycling plant. The objective was to understand if the oxidative biomarkers of lead exposure are of relevance to the functionality of DNA-repair mechanisms. We determined in all of them the Blood Lead Levels (BLL), δ-ALAD activity, lipid peroxidation, DNA damage (alkaline comet assay) and the ability to repair damage induced by ionizing radiation. Our results indicate that Pb-exposed workers exceed the permissible exposure limits and present high values of all variables determined. It was found that BLL and genotoxicity determined in workers show correlation with years worked, δ-ALAD activity and DNA repair capacity, while lipid peroxidation only correlated with BLL. The main result of the study was the detection of elevated oxidative damage in workers exposed to Pb, with no correlation established with the functionality of DNA repair mechanisms (they only repair 50 % of the induced damage). This finding suggests that the oxidative damage generated by Pb partially compromises the genetic stability of these workers, who have worked an average of 5 years at this recycling plant despite exceeding permissible exposure levels. This highlights the need for future studies to determine the induction of systemic homeostasis mechanisms that remain functional in workers, despite their exposure levels.