Polybrominated diphenyl ethers (PBDEs) effects on Chironomus sancticaroli larvae after short-term exposure

- Effects of BDE-17, BDE-47 and BDE-99 on C. sancticaroli larvae were examined.
- AChE, α and β esterase, and GST activity were influenced by the studied PBDEs.
- DNA strand breaks were observed in larvae exposed to some BDE-99 concentrations.
- PBDEs influenced the normal metabolism of the C. sancticaroli.

In-vivo effects of polybrominated diphenyl ethers (PBDEs) containing 3, 4 and 5 bromine atoms were tested on fourth-instar larvae of Chironomus sancticaroli (Diptera: Chironomidae) after 48 h of exposure, by measuring the activity of the acetyl cholinesterase, alpha and beta esterases and glutathione S-transferase. The PBDE congeners 2,2′,4-triBDE (BDE-17), 2,2′,4,4′-tetraBDE (BDE-47) and 2,2′,4,4′,5-pentaBDE (BDE-99) were evaluated at 0.5, 1.0, 2.0 and 3.0 ng mL−1. Acetyl cholinesterase activity decreased significantly (p≤0.05) at all evaluated concentrations of the three PBDE congeners, except for larvae exposed to BDE-17 at 1.0 and 2.0 ng mL−1. The significant inhibition of acetyl cholinesterase activity ranged from 18% (BDE-47 at 0.5 ng mL−1) to 72% (BDE-47 at 2.0 ng mL−1). The enzymes alpha and beta esterase were also affected by the three congeners, reducing their activity from 14% (BDE-99 at 1.0 ng mL−1) to 52% (BDE-47 at 2.0 ng mL−1) and from 7% (BDE-99 at 2.0 ng mL−1) to 34% (BDE-47 at 3.0 ng mL−1) respectively. Substantial increments in glutathione S-transferase activity were similarly observed, varying from 138% (BDE-99 2.0 at ng mL−1) to 346% (BDE-17 at 1.0 ng mL−1). DNA strand breaks were detected exclusively in larvae exposed to BDE-99 at 2.0 and 3.0 ng mL−1 (H=11.7, p=0.019). These results showed that C. sancticaroli larvae were sensitive to the PBDEs treatments under the experimental conditions.

The polybrominated diphenyl ethers, BDE-17, BDE-47 and BDE-99 influenced the activities of the neurotoxic enzymes acetyl cholinesterase, alpha and beta esterases, as well as the antioxidant defence enzyme glutathione-S-transferase of Chironomus sancticaroli larvae. In addition, BDE-99 triggered DNA strand breaks. Chironomid species are important components of aquatic food chain and aquatic environments.192