Human mercury exposure and irregular menstrual cycles in relation to artisanal gold mining in Colombia

Abstract

Introduction: Artisanal mining commonly extracts gold with an amalgamation process that uses mercury. The reproductive effects from exposure to elemental mercury used in gold mining have not been sufficiently studied.

Objective: To evaluate the effect of the exposure to elemental mercury used in gold mining on menstrual cycle regularity and the occurrence of miscarriages in Colombia.

Materials and methods: An analytical cross-sectional study was conducted. The participants were female residents of gold mining districts, with a history of exposure to elemental mercury. Menstrual regularity and the occurrence of miscarriages were compared between these women and an unexposed group. Exposure and outcome variables were registered based on a questionnaire which was evaluated for its test-retest reproducibility. Prevalence rates were calculated using a binomial model and goodness-of-fit was evaluated.

Results: A total of 72 women exposed to mercury and 121 unexposed women participated. The average time of exposure to mercury among exposed women was 19.58 ± 9.53 years. The adjusted prevalence of irregular menstruation over the last six months was higher in the group of women chronically exposed to mercury vapors (PR=1.59, 95% CI 0.93-2.73), while there was no difference in the proportion of women with a history of miscarriages.

Conclusions: Exposure to elemental mercury used in artisanal gold mining may be associated with a higher prevalence of irregular menstrual cycles but not with the occurrence of miscarriage.