Co-occurrence and spatial distribution of organic micropollutants in surface waters of the River Aconcagua and Maipo basins in Central Chile

Organic Micropollutants (OMPs) might pose significant risks to aquatic life and have potential toxic effects on humans. These chemicals typically occur as complex mixtures rather than individually. Information on their co-occurrence and their association with land use is largely lacking, even in industrialized countries. Furthermore, data on the presence of OMPs in freshwater ecosystems in South America is insufficient. Consequently, we assessed the co-occurrence and distribution of OMPs, including pharmaceuticals, pesticides, personal care products, surfactants, and other industrial OMPs, in surface waters of two river basins in central Chile. We focused on identifying and ranking quantified chemicals, classifying their mode of actions, as well as correlating their occurrence with distinct land uses. We identified and quantified 311 compounds that occurred at least once in the River Aconcagua and River Maipo basins, encompassing compounds from urban, agricultural, industrial, and pharmaceutical sectors. Pharmaceuticals were the most frequently occurring chemicals, followed by pesticides, personal care and household products. OMPs with neuroactive properties dominated surface waters in Central Chile, along with OMPs known to alter the cardiovascular and endocrine systems of humans and aquatic animals. Finally, we observed positive correlations between agricultural and urban land uses and OMPs. Our findings represent a step forward in extending current knowledge on the co-occurrence patterns of OMPs in aquatic environments, particularly in developing countries of the southern hemisphere.