Persistence, bioaccumulation and vertical transfer of pollutants in long-finned pilot whales stranded in Chilean Patagonia

• Published in: The Science of the total environment 2021-05, Vol.770, p.145259, Article 145259
• Main Authors: Garcia-Cegarra, Ana M., Jung, Jean-Luc, Orrego, Rodrigo, Padilha, Janeide de A., Malm, Olaf, Ferreira-Braz, Bernardo, Santelli, Ricardo E., Pozo, Karla, Pribylova, Petra, Alvarado-Rybak, Mario, Azat, Claudio, Kidd, Karen A., Espejo, Winfred, Chiang, Gustavo, Bahamonde, Paulina
• Format: Article
• Language: English
• Subjects: Animals; Bioaccumulation; Biodiversity; Chile; Chilean Patagonia; Environmental Monitoring; Environmental Pollutants; Fin Whale; Globicephala melas; Life Sciences; Mass stranding; Persistent organic pollutants; Systematics, Phylogenetics and taxonomy; Trace elements; Water Pollutants, Chemical - analysis; Whales, Pilot
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2021.145259

Long-finned pilot whales (LFPW) are cetaceans with strong social groups often involved in mass strandings worldwide. However, these beachings occur for reasons that are not fully understood. In 2016, 124 LFPW were stranded on the Chilean Patagonian islands, offering a unique opportunity to obtain crucial information on the ecology, biology, and genetics of this population. In addition, we examined whether persistent organic pollutants (POPs) and trace elements (TEs) were responsible for this mass mortality. Stable isotopes (δ13C & δ15N) and genetic analyses were used to reconstruct the trophic ecology, social structure, and kinship of LFPW and compared to POPs and TEs levels found in LFPW. Mitochondrial DNA analyses on 71 individuals identified four maternal lineages within the stranded LFPW. Of these animals, 32 individuals were analyzed for a suite of POPs, TEs, and lipid content in blubber. The highest levels were found for ΣDDXs (6 isomers) (542.46 ± 433.46 ng/g, lw) and for total Hg (2.79 ± 1.91 mg/kg, dw). However, concentrations found in these LFPW were lower than toxicity thresholds and those reported for LFPW stranded in other regions. Evidence was found of ΣDDX, Σ7PCBs, and Cd bioaccumulation and maternal transfer of POPs in mother/offspring groups. Nevertheless, no clear relationship between contaminant concentrations and LFPW mortality was established. Further research is still needed to assess LFPW populations including conservations status and exposure to chemicals in remote areas such as Patagonia. [Display omitted] •A mass stranding of Globicephala melas occurred in northern Chilean Patagonia.•Samples were collected for genetic, stable isotopes and pollutant analyses.•Bioaccumulation of DDXs, PCBs and Cd was observed in adult individuals.•Maternal transfer of PCBs, DDXs and HCH occurred among mother/offspring pairs.•We demonstrate the persistence of pollutants in top predators of Chilean Patagonia.