Influence of delipidation on Hg analyses in biological tissues: a case study for an Antarctic ecosystem

• Published in: Water, Air, & Soil Pollution
• Main Authors: Cipro, Caio, Bustamante, Paco, Montone, Rosalinda
• Other Authors: LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Instituto Oceanográfico, Universidade de São Paulo (USP)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: food web; delipidation; mercury; Antarctica; [SDV.TOX.ECO]Life Sciences [q-bio]/Toxicology/Ecotoxicology; Antarctic; Weddell; Antarc*; Antarctic Fur Seal; Cape Petrel; Crabeater Seal; Elephant Seal; Southern Elephant Seal; Weddell Seal
• Online Access: https://hal.archives-ouvertes.fr/hal-01683626; https://hal.archives-ouvertes.fr/hal-01683626/document; https://hal.archives-ouvertes.fr/hal-01683626/file/Cipro%20et%20al%202017%20WATE.pdf; https://doi.org/10.1007/s11270-017-3367-8

International audience The use of low-polarity organic solvents is widespread in cleanup/extraction processes in order to carry compounds of interest, remove interferences and separate phases, among other uses. A large number of studies have used delipidation to remove excess of lipids to analyse carbon stable isotopes in biological tissues for trophic and behavioural ecology investigations. In this context, the primary aim of this study is to assess the influence of one delipidation process on the results of total mercury (Hg) analyses and the possible use of delipidated samples from previous analyses, such as for stable isotopes, in Hg level determination. Samples of vegetation (angiosperm, lichens and mosses), invertebrates (krill and limpets), fish (marbled and black rockcod), bird liver and eggs (Antarctic, Gentoo and Adélie penguins, kelp gull, Antarctic tern, cape petrel and giant southern petrel) and pinniped tissues (Weddell seal, crabeater seal, southern elephant seal and Antarctic fur seal) were analysed for Hg before and after delipidation by cyclohexane. The difference between the two measurements ranged individually from −63 to 136% (in the moss Sanionia uncinata) and the averages ranged from −60 to 66% (in pinniped tissues). The proportion of organic Hg, which presents considerable lipophilicity, but also high affinity for sulfhydryl groups in proteins, might be responsible for such variability. Given the limitations of our study, we think it is safe to say that delipidated samples could not be used to infer total Hg values in non-delipidated ones.