How did a tailings spill change the distribution of legacy organochlorine compounds in a Southeast Atlantic inner shelf area: Is a hidden danger being transferred to the ocean?

Ana Caroline Cabral; Amanda Câmara de Souza; Fabian Sá; Renato Rodrigues Neto; César C Martins

doi:10.1016/j.scitotenv.2023.166939

How did a tailings spill change the distribution of legacy organochlorine compounds in a Southeast Atlantic inner shelf area: Is a hidden danger being transferred to the ocean?

Sci Total Environ. 2023 Dec 20:905:166939. doi: 10.1016/j.scitotenv.2023.166939. Epub 2023 Sep 13.

Authors

Ana Caroline Cabral¹, Amanda Câmara de Souza², Fabian Sá³, Renato Rodrigues Neto³, César C Martins⁴

Affiliations

¹ Centro de Estudos do Mar, Campus Pontal do Paraná, Universidade Federal do Paraná, Caixa Postal 61, 83255-976 Pontal do Paraná, PR, Brazil; Programa de Pós-Graduação em Sistemas Costeiros e Oceânicos, Universidade Federal do Paraná, Caixa Postal 61, 83255-976 Pontal do Paraná, PR, Brazil.
² Centro de Estudos do Mar, Campus Pontal do Paraná, Universidade Federal do Paraná, Caixa Postal 61, 83255-976 Pontal do Paraná, PR, Brazil.
³ Laboratório de Geoquímica Ambiental e Poluição Marinha, Departamento de Oceanografia e Ecologia, Universidade Federal do Espírito Santo, Av. Fernando Ferrari, 514, Vitória CEP 29075-910, ES, Brazil.
⁴ Centro de Estudos do Mar, Campus Pontal do Paraná, Universidade Federal do Paraná, Caixa Postal 61, 83255-976 Pontal do Paraná, PR, Brazil. Electronic address: ccmart@ufpr.br.

PMID: 37709099
DOI: 10.1016/j.scitotenv.2023.166939

Abstract

Polychlorinated biphenyls (PCBs) and dichloro-diphenyl-trichloroethane (DDT) were evaluated in water and sediments from the Espírito Santo Inner Shelf (ESIS), Brazil, three years after the Fundão dam failure (FDF). We discuss the levels, sources, fate, and current environmental risks of these contaminants on temporal and spatial scales. In addition, the associated coastal dispersion patterns, water-sediment exchange trends, and environmental alterations were also discussed. Low contributions and no environmental risks were verified for PCBs after FDF. However, the low concentrations and frequency of occurrence in the samples did not allow for further reliable conclusions regarding the source of this contaminant. In contrast, hazard risk has been detected for DDTs in water and sediments. In sediments, there were a significant increase in level (up to 13.42 ng g^-1; outlier = 369.6 ng g^-1), inventory (maximum = 35.98 ng cm^-2) and mean total mass (21.1 ± 39.4 kg) of DDTs after FDF. The integrated assessment of the spatial distribution in water and sediment suggests that DDTs was released from the Doce River, travelled south by the water column, and returned to the mouth region by northward sediment transport, where it accumulated. However, intense rainfall increased the input of DDTs to the ESIS and may have also altered its spatial distribution. Fugacity fraction analysis (ƒƒ) indicated a net flux of DDTs from water to sediment, suggesting that vertical sinking was an important transport process in this area. Finally, the findings indicate that FDF contributed to DDTs input on ESIS by remobilizing contaminated past sediments and soils from the Doce River drainage basin. This contribution is expected to continue since a large amount of tailings is still stored in the river basin and estuary. These results highlight the importance of assessing the indirect impacts of large-scale land disasters on marine environments, and may be helpful in future interpretations of additional local trends and global inventories of legacy pollutants.

Keywords: Fugacity; Persistent organic pollutants; Pollutant remobilization; Tailing dam failure; Water-sediment exchange.