Geological context and human exposures to element mixtures in mining and agricultural settings in Colombia

Anthropogenic and natural sources contribute to chemical mixtures in air, water, and soil, posing potential risks to the environment and human health. To understand the interplay between element profiles in the human body, geographical location, and associated economic activities, we carried out an observational analytic cross-sectional study. The study recruited 199 participants from three municipalities, two of which had gold-mining as their primary economic activity, while the other was dedicated to agricultural and other local activities not related to mining. The concentrations of a total of 30 elements in human hair samples and 21 elements in environmental soil samples were measured using various spectrometry techniques. Unsupervised clustering analysis using Self-Organizing Maps was applied to human hair samples to analyze element concentrations. Distinct clusters of individuals were identified based on their hair element profiles, which were mapped to geographical location and economic activities. While higher levels of heavy metals (Ag, As, Hg, and Pb) were observed in individuals engaged in mining activities in certain clusters, individuals in agricultural areas show higher concentrations of elements found in pesticides (Ba and Sr). However, the elemental composition of hair is influenced not only by the anthropogenic activities but also by the inherent geological context where people live. Our findings highlight the significance of accounting for environmental factors when evaluating human health risks, as the intricate mixture of elements can yield valuable insights for targeted health interventions.