Comparative toxicity of trophic exposures to polybrominated compounds (2, 4, 6 - Tribromophenol and BDE-209) to Oreochromis niloticus (Linnaeus, 1758)

Abstract

In the last decades, there has been an increase in demand for new polymers, including flame-retardants compounds, to meet fire prevention by international safety standards. The decabromodiphenyl ether (BDE-209) is a polybrominated diphenyl ether (PBDE) congener still in use worldwide. This compound presents lipophilic properties and so is easily bioaccumulated in the food chain. The 2, 4, 6 - Tribromophenol (TBP) is a PBDE metabolite also used as pesticide and flame-retardant for wood conservation. In the current study, the acute and chronic toxicity of BDE-209 and TBP was evaluated in Oreochromis niloticus through the analyses of redox unbalance, neurotoxicity and histopathological biomarkers after acute (24, 48, 72 and 96 h) and chronic (90 days) exposures to 0.5, 5 and 50 ng/g of the PBDEs. The results showed effects in GST activity and damage to biomolecules in both acute and chronic exposures. Histopathological findings were observed in the acute experiment, while hepatocyte lesions were found in both experiments. Only BDE-209 presented neurotoxic effects. The current study revealed new endpoints related with polybrominated compounds in fish, highlighting the needs to review the risk of exposure to biota and human populations.