Spatial Variation in Contaminant Occurrence in Marine Fishes and Prawns from Coastal Tanzania

Ane Haarr; Eliezer B Mwakalapa; Jan L Lyche; Aviti J Mmochi; Anuschka Polder; Anders Ruus; Katrine Borgå

doi:10.1002/etc.5254

Spatial Variation in Contaminant Occurrence in Marine Fishes and Prawns from Coastal Tanzania

Environ Toxicol Chem. 2022 Feb;41(2):321-333. doi: 10.1002/etc.5254. Epub 2022 Jan 24.

Authors

Ane Haarr¹, Eliezer B Mwakalapa², Jan L Lyche³, Aviti J Mmochi⁴, Anuschka Polder³, Anders Ruus^{1

5}, Katrine Borgå^{1

6}

Affiliations

¹ Department of Biosciences, University of Oslo, Oslo, Norway.
² Department of Natural Sciences, Mbeya University of Science and Technology, Mbeya, Tanzania.
³ Department of Paraclinical Sciences, Norwegian University of Life Sciences, Ås, Norway.
⁴ Institute of Marine Sciences, University of Dar es Salaam, Zanzibar, Tanzania.
⁵ Norwegian Institute for Water Research, Oslo, Norway.
⁶ Center for Biogeochemistry in the Anthropocene, University of Oslo, Oslo, Norway.

PMID: 34888929
DOI: 10.1002/etc.5254

Abstract

There are limited data on organic contaminants in marine biota from coastal Tanzania, especially on the occurrence of industrial-use contaminants such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). The present study, performed in 2018-2019 in coastal Tanzania and Zanzibar Island, aimed at assessing spatial variation in the occurrence of PCBs; brominated flame retardants (BFRs), including PBDEs; and organochlorine pesticides, including dichlorodiphenyltrichloroethane (DDT), among three locations that differ in degree of anthropogenic activity. Analyzed samples included edible tissues of marine fishes and prawns representing different trophic levels and habitats. The results indicate a mainland-island difference, with fishes and prawns collected on Zanzibar having significantly lower PCB and DDT concentrations but higher concentrations of hexachlorobenzene compared to the two mainland locations. The highest contaminant concentrations were found in fishes and prawns collected around central Dar es Salaam harbor, with median ΣPCBs ranging from 22.3 to 577 ng/g lipid weight and ΣDDTs from 22.7 to 501 ng/g lipid weight, suggesting local sources. Concentrations of PBDEs were similar among locations, suggesting more diffuse sources. None of the "newer-type" BFRs, including compounds introduced as replacements for PBDEs, were detected in the present study. Stable isotope values of carbon (δ¹³ C) and nitrogen (δ¹⁵ N) varied among locations, and the relationship between contaminants and δ¹⁵ N varied among locations and habitat (pelagic/demersal). Concentrations measured in the present study are below European guidelines for human consumption of fishes and prawns. However, industrial-use contaminants should be monitored in developing countries because they are contaminants of emerging concern as a result of increasing industrialization and global trade of used products and wastes. Environ Toxicol Chem 2022;41:321-333. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Keywords: Brominated flame retardants; Coastal ecosystems; Organochlorines; Polychlorinated biphenyls; Spatial variation; Tropical ecotoxicology.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
DDT
Decapoda*
Environmental Monitoring / methods
Fishes
Flame Retardants* / analysis
Halogenated Diphenyl Ethers / analysis
Hydrocarbons, Chlorinated* / analysis
Lipids
Polychlorinated Biphenyls* / analysis
Tanzania

Substances

Flame Retardants
Halogenated Diphenyl Ethers
Hydrocarbons, Chlorinated
Lipids
DDT
Polychlorinated Biphenyls