title: Methylmercury in a predatory fish (Cichla spp.) inhabiting the Brazilian Amazon.
abstract: This research tested whether limnological conditions, biological characteristics of fish and anthropogenic impacts influenced the assimilation of methylmercury into the muscle of a sedentary piscivorous fish, Cichla spp., from three rivers (Negro, Madeira, Tapajós) and two hydroelectric reservoirs (Balbina, Tucuruí) within the Brazilian Amazon. Methylmercury in this fish ranged from 0.04 to 1.43microgg(-1) w.w. across sites. No significant differences were observed in the methylmercury concentrations between males and females, or for different morphotypes of this species. Positive correlations were found between methylmercury and fish body weight. No differences were found between the weight normalized methylmercury (MeHg) concentrations or its percent of total mercury in fish from the three rivers; weight normalized MeHg was highest in one of the two reservoirs. In Rio Tapajós, where gold mining and deforestation cause high water turbidity, fish showed the highest MeHg and concentrations were different across the four sites examined. In all sampling areas, the %MeHg was found to be higher than 70.
authors.affiliation: Laboratório de Radioisótopos Eduardo Penna Franca, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), 21941-902 Rio de Janeiro, Brazil. kehrig@biof.ufrj.br
authors.forename: Helena do A
authors.initials: Hdo A
authors.lastname: Kehrig
authors.forename: Bruce M
authors.initials: BM
authors.lastname: Howard
authors.forename: Olaf
authors.initials: O
authors.lastname: Malm
mesh_terms: D000818:Animals; D001835:Body Weight; D001938:Brazil; D023681:Cichlids / Q000378:metabolism*; D003247:Conservation of Natural Resources; D005260:Female; D006046:Gold; D008297:Male; D008767:Methylmercury Compounds / Q000032:analysis*; D008906:Mining; D011235:Predatory Behavior; D045483:Rivers; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply
chemical_list: D008767:Methylmercury Compounds; D014874:Water Pollutants, Chemical; D006046:Gold