Manganese and Mercury Levels in Water, Sediments, and Children Living Near Gold-Mining Areas of the Nangaritza River Basin, Ecuadorian Amazon

Artisanal and small-scale gold-mining activities performed in mountain areas of the Southern Ecuadorian Amazon have incorporated several heavy metals into the aquatic systems, thus increasing the risk of exposure in populations living in adjacent zones. Therefore, the objective of this study was to evaluate the contamination levels of mercury (Hg) and manganese (Mn) in several rivers of the Nangaritza River basin and assess the exposure in school-aged children residing near the gold-mining zones. River water and sediment samples were collected from a highly contaminated (HE x ) and a moderately contaminated (ME x ) zones. Hair Mn (MnH) and urinary Hg (HgU) levels were determined in school-aged children living in both zones. High concentrations of dissolved Mn were found in river waters of the HE x zone (between 2660 and 3990 µg l −1 ); however, Hg levels, in general, were lower than the detection limit (DL;