Spatial and temporal distribution of potentially toxic elements and human health risk assessment in the gold mining area of Santa Rosa, Southern Ecuador

The mining industry plays a crucial role in global economic growth by providing essential raw materials for sectors such as construction, electronics, and energy. However, it also poses significant public health and environmental challenges. This study evaluates the presence of potentially toxic elements (PTEs) in water bodies in the Santa Rosa mining area, aiming to determine the spatial and temporal distribution of PTEs, as well as quantify the health risk for individuals who use the rivers for recreational purposes. Surface water samples were collected along the Santa Rosa River and Los Gringos and El Panteón streams during the dry (DS) and rainy (RS) seasons. Physicochemical parameters were measured in situ, and the content of PTEs (Al, As, Cd, Co, Cu, Fe, Mn, and Zn) was determined by ICP-MS. Multivariate statistical analyses were conducted to identify patterns and significant relationships within the dataset. The spatial and temporal distribution of PTEs was assessed using geographic information systems. The human health risk was estimated in terms of non-carcinogenic (HI) and carcinogenic risk (CR). The results revealed that Los Gringos and El Panteón streams, located near areas of intense mining activity, exhibit high concentrations of Al, Cd, Cu, Mn, and Zn, exceeding the permissible limits established by Ecuadorian regulations. Regarding risk assessment, the values of non-carcinogenic risk were below the reference threshold. In contrast, the carcinogenic risk assessment showed that 60% of river users are exposed to risk levels above the acceptable threshold, primarily due to As-exposure through incidental ingestion during recreational activities.