Measurement of as species in rice by HPLC-ICPMS after extraction with sub-critical water and hydrogen peroxide

The use of sub-critical water and hydrogen peroxide provides a fast, clean and efficient means of extracting arsenic from rice.</p

An evaluation of the use of reptile dermal scutes as a non-invasive method to monitor mercury concentrations in the environment

Reptiles are ideal organisms for the non-invasive monitoring of mercury (Hg) contamination. We have investigated Hg bioaccumulation in tissue layers of reptile dermis as a basis for establishing a standardized collection method for Hg analysis. Tissue samples from freshwater turtle species Podocnemis unifilis and Podocnemis expansa and caiman species Melanosuchus niger and Caiman crocodilus, all from the Amazonian region, were analysed in this study. We first tested the relationships between Hg concentrations in keratin and bone to Hg concentrations in muscle to determine the best predictor of Hg concentration in muscle tissue. We then investigated the potential for measuring Hg concentrations across turtle carapace growth rings as an indicator of longer term changes in Hg concentration in the environment. Hg concentrations were significantly lower in bone (120 ng g(-1) caimans and 1 ng g(-1) turtles) than keratin (3600 ng g(-1) caimans and 2200 ng g(-1) turtles). Keratin was found to be a better predictor of exposure to Hg than muscle and bone tissues for both turtles and caimans and also to be a reliable non-invasive tissue for Hg analysis in turtles. Measurement of Hg in carapace growth rings has significant potential for estimating Hg bioaccumulation by turtles over time, but full quantification awaits development and use of a matrix-matched reference material for laser ablation ICPMS analysis of Hg concentrations in keratin. Realising this potential would make a valuable advance to the study of the history of contamination in mining and industrial sites, which have until now relied on the analysis of Hg concentrations in sediments.We thank the CNPQ (Conselho Nacional de Desenvolvimento Científico e Tecnológico) who funded the BAJAQUEL Project (processo 408760/ 2006-0 Granted to Ronis Da Silveira). Laboratory analyses were funded by the Ecochemistry Laboratory at the University of Canberra and by the Research School of Earth Sciences at the Australian National University, and were performed with the assistance of Les Kinsley

Mercury Concentrations In Different Tissues of Turtle And Caiman Species From The Rio Purus, Amazonas, Brazil

Total mercury (Hg) concentrations of muscle, liver, blood, and epidermal keratin were measured in typically consumed,economically and culturally important species of turtle (Podocnemis unifilisandPodocnemis expansa) and caiman (Melanosuchus nigerandCaiman crocodilus) from the Rio Purus in the Amazon basin, Brazil. Methylmercury (MeHg) concentrations were also measured inmuscle tissue, representing thefirst analysis of MeHg concentrations in Amazonian reptile species. In muscle tissues Hg was mostlyMeHg (79–96%) for all species. No correlations existed between animal size and total Hg or MeHg concentrations for any species otherthanM. niger, possibly as a result of growth dilution or the evolution of efficient Hg elimination mechanisms. Significant linearcorrelations were found between total Hg concentrations in all pairs of nonlethally sampled tissues (keratin and blood) and internaltissues (muscle and liver) forM. nigerand between keratin and internal tissues forP. expansa, indicating that nonlethally sampledtissues can be analyzed to achieve more widespread and representative monitoring of Hg bioaccumulation in Amazonian reptiles.Although mean Hg concentrations in muscle for all species were below the World Health Organization guideline for safe consumption(500mgkg–1), mean concentrations in caiman liver were above the safe limit for pregnant women and children (200mgkg–1). Nosignificant differences were found between total Hg and MeHg concentrations in tissues from wild-caught and farm-raisedP. expansa,suggesting that farming may not reduce Hg exposure to humans.Environ Toxicol Chem2015;34:2771–278l ogico, which funded the BAJAQUEL Project (408760/2006-0 granted to R.D. Silveira). Laboratory analyses were funded by theEcochemistry Laboratory at the University of Canberra and performed withthe assistance of F. Krikowa. Turtle and caiman samples were collected inconjunction with Instituto Nacional de Pesquistas da Amaz^onia andUniversidade Federal do Amazonas, Brazil, under the auspices of IBAMAcollection permit 13347-1, IBAMA/CITES export permit 11BR006659/DF,CITES import permit 2011-AU-635980, and AQUAS quarantine permitNA111023

Remnants of the cretaceous Colombian oceanic plateau in Ecuador: Evidence from petrology and geochemistry on picrite and Mg-rich basalts

International audienc

Remnants of the cretaceous Colombian oceanic plateau in Ecuador: Evidence from petrology and geochemistry on picrite and Mg-rich basalts

International audienc

Remnants of the cretaceous Colombian oceanic plateau in Ecuador: Evidence from petrology and geochemistry on picrite and Mg-rich basalts

International audienc