Temporal trends of persistent organic pollutant contamination in Franciscana dolphins from the Southwestern Atlantic

• Published in: Environmental research Vol. 216; no. Pt 1; p. 114473
• Main Authors: Montone, Rosalinda C., Alonso, Mariana B., Santos, Marcos César O., Méndez-Fernandez, Paula, Taniguchi, Satie, Barbosa, Ana Paula M., Gonçalves, Renato M., Padilha, Janeide de Assis, Bertozzi, Carolina, da Silva, Josilene, Marigo, Juliana, Pereira, Antonio Derley S., Lourenço, Rafael A.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.01.2023
• Subjects: Animals; Brazil; Cetacean; DDT; Dichlorodiphenyltrichloroethane (DDTs); Dolphins; Environmental Monitoring; Environmental Pollutants; Halogenated Diphenyl Ethers - analysis; Hexachlorobenzene; Mirex; Persistent Organic Pollutants; Polychlorinated biphenyls (PCBs); Polychlorinated Biphenyls - analysis; Temporal trend; Water Pollutants, Chemical - analysis; Brazil; Brazil; Cetacean; Polychlorinated biphenyls (PCBs); Dichlorodiphenyltrichloroethane (DDTs); Temporal trend
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2022.114473

Persistent organic pollutants (POPs) were analyzed in 136 blubber samples of Franciscana dolphins from Brazil (Pontoporia blainvillei), which is the most threatened dolphin in the Southwestern Atlantic. The dolphins were caught by the fishery fleet and collected from 2000 to 2018 in three regions of São Paulo state: northern São Paulo (SPN), central São Paulo (SPC), and southern São Paulo (SPS). The POPs analyzed in this study were polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDTs), Mirex, hexachlorobenzene (HCB), chlordane compounds (CHLs), hexachlorocyclohexane isomers (HCHs), and polybrominated diphenyl ethers (PBDEs). The concentrations ranged from 36 to 7200 ng g−1 lipid weight (lw) and 113–42200 ng g−1 lw for predominant compounds DDTs and PCBs, respectively. Similar profiles of PCB congeners were observed with a predominance of hexachlorinated compounds, representing approximately 50% of the total PCB amount; the highest PCB concentrations were observed from Baixada Santista (SPC) proximate to a highly urbanized and industrial coastal area. Significant differences were observed between the sexes and maturity of dolphins, mainly for PCBs, DDTs, and Mirex. In general, POPs other than HCB in Franciscana dolphins showed downward temporal trends, matching the regulatory periods for restricting and/or banning these compounds. Although POP concentrations are declining, PCB levels remain high in small dolphins, suggesting adverse health effects on Franciscanas. As organic contaminants are one of the numerous threats Franciscanas have been vulnerable to along the Brazilian coast, we recommend monitoring POPs levels every five years to check for declining (or stabilizing) trends. •Franciscana dolphins showed predominantly PCBs, followed by DDTs and Mirex.•Increased proximity to highly urbanized regions indicated higher PCB levels.•Downward temporal trends were observed for most POPs in Franciscana dolphins.