Participatory assessment of pollution and health risk in artisanal and small-scale gold mining communities in Colombia

The predominantly Afro-descendant communities of Yolombó and La Toma depend on the region's rich natural resources through livelihoods such as farming, fishing, and artisanal and small-scale gold mining (ASGM). Previous studies of the region have identified elevated levels of mercury in several surface and groundwater sites. Furthermore, recent regional studies have identified human health risks associated with mercury exposure through hazard quotient (HQ) modeling and global sensitivity and uncertainty analysis (GSUA). However, there has yet to be a comprehensive analysis of water pollution involving different metals and metalloids potentially present in ASGM-influenced areas to estimate the associated environmental and human health impacts. In this study, we employed a participatory methodology to identify sources of exposure in Colombian ASGM communities through surveys, consumption diaries, and interviews. We then screened for relevant metals and metalloids through groundwater analysis using inductively coupled plasma optical emission spectroscopy (ICP-OES) and cold vapor atomic absorption spectrometry (CV-AAS). Furthermore, we calculated water pollution indices, including heavy metal pollution index (HPI), degree of contamination (Cd), heavy metal toxicity load (HMTL) and heavy metal evaluation index (HEI). Finally, we quantified human health risks related to groundwater consumption through the HQ and hazard index (HI). Although the groundwater assessed in this study generally meets United States and Colombian regulatory standards, heightened Fe, Mn, and Al levels were observed. The pollution indices generally agreed that three of the sites tested showed medium to high pollution levels. The HI showed that the combined effect of all metals tested did not substantiate risk for most participants. However, the HI of one participant, a child, exceeded the 1.00 threshold. Furthermore, the presence of Pb, despite meeting regulatory limits, necessitates further scrutiny due to its substantial impact on pollution and human health hazard indices.