An additional threat to populations predicted to collapse: Organobromine compounds of natural and anthropogenic sources in rough-toothed dolphins from the Southwestern Atlantic Ocean

Nara de Oliveira-Ferreira; Elitieri B Santos-Neto; Bárbara M R Manhães; Camila Domit; Eduardo R Secchi; Silvina Botta; Haydée A Cunha; Alexandre F Azevedo; Tatiana L Bisi; José Lailson-Brito

doi:10.1016/j.chemosphere.2023.138237

An additional threat to populations predicted to collapse: Organobromine compounds of natural and anthropogenic sources in rough-toothed dolphins from the Southwestern Atlantic Ocean

Chemosphere. 2023 May:323:138237. doi: 10.1016/j.chemosphere.2023.138237. Epub 2023 Feb 28.

Affiliations

¹ Laboratório de Mamíferos Aquáticos e Bioindicadores (MAQUA), Faculdade de Oceanografia, Universidade do Estado do Rio de Janeiro (UERJ), Rua São Francisco Xavier, 524, Postal Code: 20550-013, Rio de Janeiro, Brazil; Programa de Pós-Graduação em Ciências Biológicas - Biofísica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), Avenida Carlos Chagas Filho, 373, Postal Code: 21941-590; Rio de Janeiro, Brazil. Electronic address: nara.oliveira@biof.ufrj.br.
² Laboratório de Mamíferos Aquáticos e Bioindicadores (MAQUA), Faculdade de Oceanografia, Universidade do Estado do Rio de Janeiro (UERJ), Rua São Francisco Xavier, 524, Postal Code: 20550-013, Rio de Janeiro, Brazil.
³ Laboratório de Ecologia e Conservação (LEC), Centro de Estudos do Mar (CEM), Universidade Federal do Paraná (UFPR), Avenida Beira Mar s/n, Postal Code: 83255-000, Pontal do Paraná, Paraná, Brazil.
⁴ Laboratório de Ecologia e Conservação da Megafauna Marinha (ECOMEGA), Instituto de Oceanografia, Universidade Federal do Rio Grande (FURG), Avenida Itália, km 8, Postal Code: 96203-900, Rio Grande, Rio Grande do Sul, Brazil.
⁵ Laboratório de Mamíferos Aquáticos e Bioindicadores (MAQUA), Faculdade de Oceanografia, Universidade do Estado do Rio de Janeiro (UERJ), Rua São Francisco Xavier, 524, Postal Code: 20550-013, Rio de Janeiro, Brazil; Departamento de Genética, Instituto de Biologia Roberto Alcântara Gomes, Universidade do Estado do Rio de Janeiro (UERJ), Rua São Francisco Xavier, 524, Postal Code: 20550-013, Rio de Janeiro, Brazil.
⁶ Laboratório de Mamíferos Aquáticos e Bioindicadores (MAQUA), Faculdade de Oceanografia, Universidade do Estado do Rio de Janeiro (UERJ), Rua São Francisco Xavier, 524, Postal Code: 20550-013, Rio de Janeiro, Brazil; Programa de Pós-Graduação em Ciências Biológicas - Biofísica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), Avenida Carlos Chagas Filho, 373, Postal Code: 21941-590; Rio de Janeiro, Brazil.

PMID: 36863632
DOI: 10.1016/j.chemosphere.2023.138237

Abstract

Organic contaminants with toxic effects, like the conventional brominated flame retardants (BFRs) and BFRs of emergent concern, and their synergistic effects with other micropollutants, can be an additional threat to delphinids. Rough-toothed dolphins (Steno bredanensis) populations strongly associated with coastal environments already face a potential risk of decline due to high exposure to organochlorine pollutants. Moreover, natural organobromine compounds are important indicators of the environment's health. Polybrominated diphenyl ethers (PBDEs), pentabromoethylbenzene (PBEB), hexabromobenzene (HBB) and the methoxylated PBDEs (MeO-BDEs) were determined in the blubber of rough-toothed dolphins from three ecological populations from the Southwestern Atlantic Ocean (Southeastern, Southern and Outer Continental Shelf/Southern populations, SE, S, and OCS/S, respectively). The profile was dominated by the naturally produced MeO-BDEs (mainly 2'-MeO-BDE 68 and 6-MeO-BDE 47), followed by the anthropogenic BFRs PBDEs (mainly BDE 47). Median ΣMeO-BDE concentrations varied between 705.4 and 3346.0 ng g^-1 lw among populations and ΣPBDE from 89.4 until 538.0 ng g^-1 lw. Concentrations of anthropogenic organobromine compounds (ΣPBDE, BDE 99 and BDE 100) were higher in SE population than in OCS/S, indicating a coast - ocean gradient of contamination. Negative correlations were found between the concentration of the natural compounds and age, suggesting their metabolization and/or biodilution and maternal transference. Conversely, positive correlations were found between the concentrations of BDE 153 and BDE 154 and age, indicating low biotransformation capability of these heavy congeners. The levels of PBDEs found are concerning, particularly for SE population, because they are similar to concentrations known for the onset of endocrine disruption in other marine mammals and may be an additional threat to a population in a hotspot for chemical pollution.

Keywords: Brazilian coast; Delphinids; MeO-BDE; Organic compounds; PBDE; Pollution.

MeSH terms

Animals
Atlantic Ocean
Dolphins* / metabolism
Environmental Monitoring
Flame Retardants* / analysis
Halogenated Diphenyl Ethers / analysis
Water Pollutants, Chemical* / analysis

Substances

Halogenated Diphenyl Ethers
Water Pollutants, Chemical
Flame Retardants