title: Sex-related mercury bioaccumulation in fish from the Madeira River, Amazon.
abstract: Sex plays an important role in the kinetics and dynamics of methylmercury in some animals. Although fish is the main source of mercury exposure to consumers, the role of sex in fish-Hg bioaccumulation is less known. We studied total Hg (THg) concentrations in 2538 samples (males=1052, females=1486) of fish from different trophic levels (herbivorous, planctivorous, detritivorous, omnivorous, carnivorous, piscivorous); for each species we made a post hoc estimation of the minimum number of samples required to detect variance-based differences between sexes. Only five of the 41 studied species showed significant difference between sexes; but, no consistent dominant pattern of THg concentrations favored either sex. When grouped by trophic levels, overall mean difference in THg concentrations between males and females were not statistically significant. Correlation analysis showed sex-dependent THg bio-accumulation as a function of condition factor was statistically significant and negative for all trophic levels (detritivorous, herviborous, omnivorous, planctivorous, carnivorous, and piscivorous).
  
  
  CONCLUSIONS
  Sex is not the main driver of Hg bioaccumulation in most Amazonian fish species; however, studies have to consider the minimum number of samples required to ascertain sex effects on THg bioaccumulation. Therefore, neither the surveillance of environmental pollution nor the current food advisories based on muscle THg need to change because of fish sex.
authors.affiliation: Laboratório de Biogeoquímica Ambiental, Universidade Federal de Rondônia, Brazil. Electronic address: bastoswr@unir.br.
authors.forename: Wanderley R
authors.initials: WR
authors.lastname: Bastos
authors.affiliation: Faculdade de Ciências da Saúde, Universidade de Brasília, Brazil.
authors.forename: José G
authors.initials: JG
authors.lastname: Dórea
authors.affiliation: Instituto de Química, Universidade de Brasília, Brasília, Brazil.
authors.forename: José Vicente E
authors.initials: JVE
authors.lastname: Bernardi
authors.affiliation: Laboratório de Biogeoquímica Ambiental, Universidade Federal de Rondônia, Brazil.
authors.forename: Angelo G
authors.initials: AG
authors.lastname: Manzatto
authors.affiliation: Laboratório de Biogeoquímica Ambiental, Universidade Federal de Rondônia, Brazil; Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brazil.
authors.forename: Marilia H
authors.initials: MH
authors.lastname: Mussy
authors.affiliation: Laboratório de Biogeoquímica Ambiental, Universidade Federal de Rondônia, Brazil.
authors.forename: Leidiane C
authors.initials: LC
authors.lastname: Lauthartte
authors.affiliation: Laboratório de Biogeoquímica Costeira, Instituto de Ciências do Mar, Universidade Federal do Ceará, Brazil.
authors.forename: Luiz D
authors.initials: LD
authors.lastname: Lacerda
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brazil.
authors.forename: Olaf
authors.initials: O
authors.lastname: Malm
mesh_terms: D000818:Animals; D005260:Female; D005399:Fishes / Q000378:metabolism*; D020387:Food Chain; D008297:Male; D008628:Mercury / Q000378:metabolism*; D009132:Muscles / Q000378:metabolism; D045483:Rivers; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D014874:Water Pollutants, Chemical; D008628:Mercury
keywords: Amazon; Fish; Madeira River; Mercury; Muscle; Sex