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SC/69A/SM/06
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Resource ID
20065
Access
Open
Document Number
SC/69A/SM/06
Full Title
Persistent Organic Pollutants’ bioaccumulation and temporal trends in a resident population of the endangered Lahille’s bottlenose dolphin (Tursiops gephyreus)
Author
Bárbara Manhães, Pedro Fruet, Rodrigo Genoves, Nara De Oliveira-Ferreira, Eduardo Secchi, Elitieri Santos-Neto, Juliana Di Tullio, Silvina Botta, Lorenzo Von Fersen, Liane Dias, Jose Laílson-Brito
Authors Summary
This study aimed to characterize organochlorine compounds’ bioaccumulation- polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), and mirex in the blubber of males Lahille’s bottlenose dolphins from Patos Lagoon Estuary (PLE), southern Brazil, and to the investigate temporal trends of these compounds. Blubber biopsy samples from known adult males of Lahille’s bottlenose dolphins (n=28) were collected from living individuals between 2010 and 2020. Sampled dolphins were aged using the available long-term photoidentification database that is updated and maintained since 1974. The organochlorine compounds analyzed in the present study were PCBs and pesticides. PCBs presented higher concentrations, followed by DDTs and mirex. The high ΣPCB concentrations found in the present study (median: 79 µg.g-1 lw) are much above the thresholds established in the literature regarding PCB toxicity, which are: 1.3 µg.g-1 lw for endocrine disruption, 10 µg.g-1 lw for risk of decline in population growth rates, and 17 µg.g-1 lw in cetaceans’ blubber for physiological effects. Among pesticides, DDT’s profile reflects the historical use of DDT in PLE related to agricultural activities as well as other regions along the Brazilian coast. The mean mirex concentration was an order of magnitude higher than a previous study in PLE. PCBs showed an increase trend over the years (from 2010 to 2020) while DDT concentrations decreased from 2010 to 2015, and after that, an increase was observed. The temporal pattern described here would benefit from further analysis including a large and more balanced sample size in term of dolphin’s age and time of sampling.
Publisher
IWC
Publication Year
2023