title: Manganese and Mercury Levels in Water, Sediments, and Children Living Near Gold-Mining Areas of the Nangaritza River Basin, Ecuadorian Amazon.
abstract: 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 (HEx) and a moderately contaminated (MEx) 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 HEx zone (between 2660 and 3990 µg l(-1)); however, Hg levels, in general, were lower than the detection limit (DL; <1.0 µg l(-1)). Similarly, Mn levels in sediments were also increased (3090 to 4086 µg g(-1)). Median values of MnH in children of the HEx and MEx zones were 5.5 and 3.4 µg g(-1), respectively, whereas the median values of HgU concentrations in children living in the HEx and MEx zones were 4.4 and 0.62 µg g-creat(-1), respectively. Statistically significant differences were observed between both biomarkers in children from the HEx and MEx zones. In addition, boys presented significantly greater MnH levels in both zones. The greater MnH values were found in children living in alluvial areas, whereas children living in the high mountain areas, where some ore-processing plants are located close to or inside houses and schools, had the greater HgU concentrations. In summary, the data reported in this paper highlights that artisanal and small-scale gold-mining activities can not only produce mercurial contamination, that can also release other heavy metals (such as Mn) that may pose a risk to human health.
authors.affiliation: Dirección de Investigación, Universidad Nacional de Loja, La Argelia, Loja, Ecuador.
authors.forename: Max V
authors.initials: MV
authors.lastname: González-Merizalde
authors.affiliation: Laboratory of Toxicology, College of Pharmacy, Federal University of Bahia, Salvador, Bahia, 40170-115, Brazil.
authors.forename: José A
authors.initials: JA
authors.lastname: Menezes-Filho
authors.affiliation: Laboratorio de Análisis Químico, Universidad Nacional de Loja, La Argelia, Loja, Ecuador.
authors.forename: Claudia Teresa
authors.initials: CT
authors.lastname: Cruz-Erazo
authors.affiliation: Dirección de Investigación, Universidad Nacional de Loja, La Argelia, Loja, Ecuador.
authors.forename: Santos Amable
authors.initials: SA
authors.lastname: Bermeo-Flores
authors.affiliation: Dirección de Investigación, Universidad Nacional de Loja, La Argelia, Loja, Ecuador.
authors.forename: María Obdulia
authors.initials: MO
authors.lastname: Sánchez-Castillo
authors.affiliation: National Institute of Public Health, Mexico City, Mexico.
authors.forename: David
authors.initials: D
authors.lastname: Hernández-Bonilla
authors.affiliation: Investigador Prometeo, Universidad Nacional de Loja, La Argelia, Loja, Ecuador. abrahanmora@hotmail.com.
authors.forename: Abrahan
authors.initials: A
authors.lastname: Mora
mesh_terms: D002648:Child; D004484:Ecuador; D004781:Environmental Exposure / Q000032:analysis* / Q000706:statistics & numerical data; D005260:Female; D019015:Geologic Sediments / Q000737:chemistry*; D006801:Humans; D008297:Male; D008345:Manganese / Q000032:analysis* / Q000378:metabolism; D008628:Mercury / Q000032:analysis* / Q000378:metabolism; D008906:Mining; D045483:Rivers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data*
chemical_list: D014874:Water Pollutants, Chemical; D008345:Manganese; D008628:Mercury