title: Non-lethal sampling for mercury evaluation in crocodilians.
abstract: Mercury (Hg) is a ubiquitous environmental contaminant that poses potential threats to ecosystems due to its toxicity to humans and wildlife. The development of non-lethal sampling techniques is a critical step for evaluation of Hg in threatened species in tropical floodplain environments, where most of Hg found is the result of land use and gold mining activities, and more methylation sites are available. We evaluated the spatial and seasonal effectiveness of caudal scutes and claws to estimate Hg bioaccumulation in crocodilians (Caiman yacare), in the scarcely documented Pantanal. Hence, we investigated the potential for Hg bioaccumulation in top predators according to its proximity to mining sites, and in water bodies with different hydrological characteristics and connectivity with the main river during two phases of the flood pulse (dry and flood). The highest Hg concentrations were detected in caimans captured close to mining activities, in claws (2176 ng g(-1) ww) and caudal scutes (388 ng g(-1) ww). THg concentration in claws was related to the flood season and its mean concentration was thirteen fold higher than Hg concentration in scutes during whole year. Both tissues were found to be effective as non-lethal sampling techniques for measuring Hg bioaccumulation in reptiles over time. Nevertheless, claw tissue seems to have a more consistent result, since its constitutional chemical characteristics makes it a better indicator of spatial patterns that influence on Hg exposure.
authors.affiliation: Mato Grosso State University, UNEMAT, Biology Department, Cáceres, Brazil.
authors.forename: Wilkinson L
authors.initials: WL
authors.lastname: Lázaro
authors.affiliation: Mato Grosso State University, UNEMAT, Biology Department, Cáceres, Brazil.
authors.forename: Robson F
authors.initials: RF
authors.lastname: de Oliveira
authors.affiliation: Mato Grosso State University, UNEMAT, Biology Department, Cáceres, Brazil.
authors.forename: Manoel
authors.initials: M
authors.lastname: dos Santos-Filho
authors.affiliation: Mato Grosso State University, UNEMAT, Biology Department, Cáceres, Brazil.
authors.forename: Carolina J
authors.initials: CJ
authors.lastname: da Silva
authors.affiliation: Federal University of Rio de Janeiro, Carlos Chagas Filho Biophysics Institute, Eduardo Penna Franca Radioisotopes Laboratory, Rio de Janeiro, Brazil.
authors.forename: Olaf
authors.initials: O
authors.lastname: Malm
authors.affiliation: Mato Grosso State University, UNEMAT, Biology Department, Cáceres, Brazil.
authors.forename: Áurea R A
authors.initials: ÁR
authors.lastname: Ignácio
authors.affiliation: Environmental Chemistry Department, Institute of Environmental Assessment and Water Research, IDAEA-CSIC, Barcelona, Spain. Electronic address: sergi.diez@idaea.csic.es.
authors.forename: Sergi
authors.initials: S
authors.lastname: Díez
mesh_terms: D000489:Alligators and Crocodiles / Q000378:metabolism*; D000818:Animals; D001938:Brazil; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D006801:Humans; D008628:Mercury / Q000032:analysis* / Q000493:pharmacokinetics; D008906:Mining; D045483:Rivers / Q000737:chemistry; D012621:Seasons; D013048:Specimen Handling / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000493:pharmacokinetics
chemical_list: D014874:Water Pollutants, Chemical; D008628:Mercury
keywords: Caiman; Caudal scutes; Claws; Flood and dry season; Mercury; Pantanal; Reptile