Correlation between gold and mercury in human blood among individuals in northwestern Tanzania

Mercury is a highly toxic metal of major global health concern, with exposure disproportionately affecting low- and middle-income countries (LMICs) where artisanal and small-scale gold mining (ASGM) is common. While mercury exposure has been well documented among mining populations, less is known about exposure in general urban populations. We analyzed baseline data from 1000 adults enrolled in the Mwanza HIV and Cardiovascular Disease cohort (2015–2019) in northern Tanzania. Blood total mercury (T-Hg) and total gold (T-Au) concentrations were measured from dried blood spots using inductively coupled plasma mass spectrometry. Associations between T-Hg and T-Au concentrations were evaluated using Spearman’s rank correlation. All participants had detectable blood mercury levels, with a median T-Hg concentration of 5.02µg/l, and 7.2% had levels exceeding the World Health Organization toxic threshold of≥20 µg/l. Detectable T-Au was observed in approximately 60% of participants, with a median T-Au concentration of 0.09µg/l. In bootstrap multivariable regression analyses, HIV infection was associated with higher T-Au concentrations. T-Hg and T-Au concentrations were moderately positively correlated in Spearman’s rank correlation. After multivariable adjustment, T-Hg remained positively associated with T-Au concentrations.