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

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 48h 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 3.0ngmL(-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 2.0ngmL(-1). The significant inhibition of acetyl cholinesterase activity ranged from 18% (BDE-47 at 0.5ngmL(-1)) to 72% (BDE-47 at 2.0ngmL(-1)). The enzymes alpha and beta esterase were also affected by the three congeners, reducing their activity from 14% (BDE-99 at 1.0ngmL(-1)) to 52% (BDE-47 at 2.0ngmL(-1)) and from 7% (BDE-99 at 2.0ngmL(-1)) to 34% (BDE-47 at 3.0ngmL(-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 1.0ngmL(-1)). DNA strand breaks were detected exclusively in larvae exposed to BDE-99 at 2.0 and 3.0ngmL(-1) (H=11.7, p=0.019). These results showed that C. sancticaroli larvae were sensitive to the PBDEs treatments under the experimental conditions.