Abstract:
Mercury can be very toxic to human health even at low dose of exposure. Artisanal small-
scale miners (ASGMs) use mercury in gold production, hence are at risk of mercury-induced
organ dysfunction.
Aim
We determined the association between mercury exposure, thyroid function and work-
related factors among artisanal small-scale gold miners in Bibiani- Ghana.
Method
We conveniently recruited 137 consenting male gold miners at their work site in Bibiani-
Ghana, in a comparative cross-sectional study. Occupational activities and socio-demo-
graphic data of participants were collected using a questionnaire. Blood sample was ana-
lysed for total mercury and thyroid hormones.
Results
Overall, 58.4% (80/137) of the participants had blood mercury exceeding the occupational
exposure threshold (blood mercury 5μg/L). T3(P<0.0001) and T4(P<0.0001) were signifi-
cantly reduced among the exposed group compared to the non-exposed. TSH showed no
significant variation between the exposed and non-exposed groups. Longer work duration
( 5years), gold amalgamation, gold smelting and sucking of excess mercury with the
mouth were associated with increased odds of mercury exposure. Blood mercury showed
negative correlation with T3(r = -0.29, P<0.0001), and T4(r = -0.69, P<0.0001) and positive
correlation with work duration (r = 0.88, P<0.001). Even though a positive trend of associa-
tion between blood mercury and TSH levels was recorded, it was not significant (r = 0.07, P
= 0.4121)
Conclusion
Small scale miners in Bibiani are exposed to mercury above the occupational threshold
which may affect thyroid hormone levels.
