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Distribution and bioavailability of cadmium in ornithogenic coral-sand sediments of the Xisha archipelago, South China Sea
2012
Liu, Xiaodong | Lou, Chuangneng | Xu, Liqiang | Sun, Liguang
Total cadmium (Cd) concentrations in four ornithogenic coral-sand sedimentary profiles displayed a strong positive correlation with guano-derived phosphorus, but had no correlation with plant-originated organic matter in the top sediments. These results indicate that the total Cd distributions were predominantly controlled by guano input. Bioavailable Cd and zinc (Zn) had a greater input rate in the top sediments with respect to total Cd and total Zn, and a positive correlation with total organic carbon (TOC) derived from plant humus. Multi-regression analysis showed that the total Cd and TOC explained over 80% of the variation of bioavailable Cd, suggesting that both guano and plant inputs could significantly influence the distribution of bioavailable Cd, and that plant biocycling processes contribute more to the recent increase of bioavailable Cd. A pollution assessment indicates that the Yongle archipelago is moderately to strongly polluted with guano-derived Cd.
显示更多 [+] 显示较少 [-]Size dependent bioaccumulation and ecotoxicity of gold nanoparticles in an endobenthic invertebrate: The Tellinid clam Scrobicularia plana
2012
Pan, Jin-Fen | Buffet, Pierre-Emmanuel | Poirier, Laurence | Amiard-Triquet, C. | Gilliland, Douglas | Joubert, Yolaine | Pilet, Paul | Guibbolini, Marielle | Risso de Faverney, Christine | Roméo, Michèle | Valsami-Jones, Eugenia | Mouneyrac, Catherine
Gold nanoparticles (AuNPs) have important technological applications resulting in an increased potential for release to the environment, and a greater possibility of toxicological effects. The marine bivalve Scrobicularia plana was exposed to AuNPs of size 5, 15 and 40nm during a 16 d laboratory exposure at 100μg Au L⁻¹. After exposure to AuNPs forming aggregates (>700nm), the clams accumulated Au in their soft tissues. Biochemical (biomarkers) and behavioral (burrowing and feeding) responses were investigated. Au NPs were responsible of metallothionein induction (5, 40nm), increased activities of catalase (15, 40nm) and superoxide dismutase (40nm) and of glutathione S-transferase by the three sizes of AuNPs indicating defense against oxidative stress. Exposure to AuNPs impaired burrowing behavior. However, it must be underlined that these effects were observed at a dose much higher than expected in the environment.
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