No effect of mercury exposure on kidney function during ongoing artisanal gold mining activities in Colombia

Abstract

This cross-sectional study examined whether people who are exposed to mercury (Hg) vapours in ongoing artisanal gold mining activities have alteration in kidney function monitoring parameters. The study enrolled 164 miners and 127 participant controls. The Hg concentrations for miners and control participants were measured in blood (B-Hg; median 7.0 vs. 2.5 µg/L), urine (U-Hg; median 3.9 vs. 1.5 µg/g creatinine) and hair (H-Hg; median 0.8 vs. 0.4 µg/g hair). The biomarkers of renal function were creatinine, albumin and excretion of β-2 microglobulin. Glomerular filtration rate (eGFR) was calculated using the chronic kidney disease epidemiology collaboration equation. Significant statistical differences were found in Hg concentrations and eGFR levels between the two study groups ( p < 0.01) but not with the other biomarkers of renal function. A multiple regression model was applied to explore the relationship of eGFR levels and Hg concentrations. However, no association was found between the prevalence of reduced eGFR (<71.96 mL/min/1.73 m) and the B-Hg or U-Hg levels after adjustment for covariates. Nevertheless, it was observed that having B-Hg levels above 10 µg Hg/L decreased the eGFR by 1.7 mL/min/1.73 m (confidence interval 95% -5.1 to 1.7) compared to having levels below 2.0 µg Hg/L. Our results found no support for kidney damage associated with Hg vapour exposure in ongoing artisanal gold mining, whose population has a level of Hg exposure from low to moderate (B-Hg from 3.4 to 11.0 µg/L and U-Hg from 1.3 to 9.6 µg/g creatinine).

Chemical Element Mixtures and Kidney Function in Mining and Non-Mining Settings in Northern Colombia

“…The goldmining district at northeast of the country include municipalities in which large-scale and artisanal gold mining are combined within the same territory. Our previous work on this mining population provided no support for early kidney damage associated with Hg vapor exposure in artisanal gold miners [20]. We also provided evidence that germline genetic variation, particularly in multispecific transporters and glutathione-related genes, mitigates Hg nephrotoxicity in miners [21,22].…”

“…The objective of that study was to assess the effects of chronic exposure to Hg in artisanal gold mining settings on biomarkers of renal dysfunction comparing non-exposed and exposed groups of individuals. Selection criteria and population characteristics were previously described in detail [20]. In that study we assessed the effects of Hg on health as this metal has been widely used by artisanal miners to extract gold using amalgamation procedures [27].…”

An improved method for assessing environmental impacts caused by chemical pollutants: A case study in textiles production

“…Mercury is mainly in the form of vapour into the respiratory tract. Occupational mercury poisoning is mostly chronic (Rodríguez et al, 2016). Any form of mercury in sufficiently large doses can be toxic.…”