RESUMO
The whale shark (Rhincodon typus) is an endangered species that may be exposed to micro- and macro-plastic ingestion as a result of their filter-feeding activity, particularly on the sea surface. In this pilot project we perform the first ecotoxicological investigation on whale sharks sampled in the Gulf of California exploring the potential interaction of this species with plastic debris (macro-, micro-plastics and related sorbed contaminants). Due to the difficulty in obtaining stranded specimens of this endangered species, an indirect approach, by skin biopsies was used for the evaluation of the whale shark ecotoxicological status. The levels of organochlorine compounds (PCBs, DDTs), polybrominated diphenyl ethers (PBDEs) plastic additives, and related biomarkers responses (CYP1A) were investigated for the first time in the whale shark. Twelve whale shark skin biopsy samples were collected in January 2014 in La Paz Bay (BCS, Mexico) and a preliminary investigation on microplastic concentration and polymer composition was also carried out in seawater samples from the same area. The average abundance pattern for the target contaminants was PCBs>DDTs>PBDEs>HCB. Mean concentration values of 8.42ng/g w.w. were found for PCBs, 1.31ng/g w.w. for DDTs, 0.29ng/g w.w. for PBDEs and 0.19ng/g w.w. for HCB. CYP1A-like protein was detected, for the first time, in whale shark skin samples. First data on the average density of microplastics in the superficial zooplankton/microplastic samples showed values ranging from 0.00items/m3 to 0.14items/m3. A focused PCA analysis was performed to evaluate a possible correlation among the size of the whale sharks, contaminants and CYP1A reponses. Further ecotoxicological investigation on whale shark skin biopsies will be carried out for a worldwide ecotoxicological risk assessment of this endangerd species.
Assuntos
Espécies em Perigo de Extinção , Exposição Ambiental/efeitos adversos , Plásticos/toxicidade , Tubarões/fisiologia , Pele/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Poluição da Água/efeitos adversos , Animais , Biomarcadores/metabolismo , Biópsia/veterinária , Família 1 do Citocromo P450/metabolismo , DDT/análise , DDT/toxicidade , Monitoramento Ambiental , Feminino , Proteínas de Peixes/metabolismo , Éteres Difenil Halogenados/análise , Éteres Difenil Halogenados/toxicidade , Masculino , México , Oceano Pacífico , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/toxicidade , Projetos Piloto , Plásticos/análise , Bifenilos Policlorados/análise , Bifenilos Policlorados/toxicidade , Análise de Componente Principal , Água do Mar/química , Tubarões/crescimento & desenvolvimento , Pele/química , Pele/crescimento & desenvolvimento , Pele/metabolismo , Poluentes Químicos da Água/análiseRESUMO
The main objective of this study was to apply a set of sensitive non-lethal biomarkers in skin biopsies of fin whales (Balaenoptera physalus) to evaluate the toxicological status of this mysticete in the Pelagos Sanctuary (Mediterranean Sea) and in the Gulf of California (Sea of Cortez-Mexico). We developed a "multi-trial diagnostic tool" (based on field and in vitro studies), combining molecular biomarkers (western blot of CYP1A1, CYP2B) and gene expression (qRT-PCR of HSP70, ERα, AHR, E2F-1) with the analysis of OCs, PAHs and PBDEs. The study revealed a higher level of toxicological stress in the Mediterranean fin whales.