title: Chromium distribution in an Amazonian river exposed to tannery effluent.
abstract: This study aims to evaluate the Cr concentrations in surface water, suspended particles, and bottom sediments exposed to tannery effluent releases in the Candeias River. Cr concentrations were compared in relation to environmental thresholds imposed by United States Environmental Protection Agency (USEPA) and the Brazilian Environmental Council (CONAMA), and the geoaccumulation index (Igeo) was calculated in bottom sediment. Samples were collected in flood and dry seasons. Cr extraction was done by an acid extraction and quantified by flame atomic absorption spectrometry. Most samples were found to be below the environmental thresholds imposed by CONAMA and USEPA, except in the one from the discharge zone sampled during the dry season, showing values 1.5 and 6.1 higher than CONAMA in water and bottom sediment, respectively. Cr concentrations were significantly higher (P < 0.001) in suspended particles during dry season than flood season. Surface water and bottom sediment did not show significant differences between the seasons. The Igeo revealed an enrichment of Cr in bottom sediments after discharge zone, indicating that the effluent may be contributing to metal accumulation in the sediment. Apparently, the Candeias River shows a wash behavior on the river bottom, leaching the accumulated metal deposited on the riverbed to other areas during the flood pulses, which decreases Cr concentration in the discharge zone during dry seasons. Thus, this behavior can promote Cr dispersion to unpolluted areas.
authors.affiliation: Laboratory of Environmental Biogeochemistry Wolfgang Christian Pfeiffer, Federal University of Rondônia, BR-364, Km 9.5, toward Rio Branco, Porto Velho, Rondônia, Brazil. edu-d20@hotmail.com.
authors.forename: Eduardo Araujo
authors.initials: EA
authors.lastname: de Sousa
authors.affiliation: Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, 373, Av. Carlos Chagas Filho, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Cleber Calado
authors.initials: CC
authors.lastname: Luz
authors.affiliation: Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, 373, Av. Carlos Chagas Filho, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Dario Pires
authors.initials: DP
authors.lastname: de Carvalho
authors.affiliation: Department of Civil and Water Engineering, Laval University, 1065, av. de la Médecine, Quebec City, Quebec, Canada.
authors.forename: Caetano Chang
authors.initials: CC
authors.lastname: Dorea
authors.affiliation: Laboratory of Environmental Biogeochemistry Wolfgang Christian Pfeiffer, Federal University of Rondônia, BR-364, Km 9.5, toward Rio Branco, Porto Velho, Rondônia, Brazil.
authors.forename: Igor Bruno Barbosa
authors.initials: IB
authors.lastname: de Holanda
authors.affiliation: Laboratory of Environmental Biogeochemistry Wolfgang Christian Pfeiffer, Federal University of Rondônia, BR-364, Km 9.5, toward Rio Branco, Porto Velho, Rondônia, Brazil.
authors.forename: Ângelo Gilberto
authors.initials: ÂG
authors.lastname: Manzatto
authors.affiliation: Laboratory of Environmental Biogeochemistry Wolfgang Christian Pfeiffer, Federal University of Rondônia, BR-364, Km 9.5, toward Rio Branco, Porto Velho, Rondônia, Brazil.
authors.forename: Wanderley Rodrigues
authors.initials: WR
authors.lastname: Bastos
mesh_terms: D001938:Brazil; D002857:Chromium / Q000032:analysis*; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000032:analysis*; D007220:Industrial Waste / Q000032:analysis*; D052638:Particulate Matter / Q000032:analysis*; D045483:Rivers / Q000737:chemistry*; D012621:Seasons; D013054:Spectrophotometry, Atomic; D013633:Tanning; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D007220:Industrial Waste; D052638:Particulate Matter; D014874:Water Pollutants, Chemical; D002857:Chromium
keywords: Amazon; Chromium enrichment; Environmental impact; Geoaccumulation; Livestock