Toxic Effects Of BDE-47 And The Lixivium Of Soil And Sediment From Electronic Waste Recycling Site To Aquatic Organisms

Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants in numerous electronic products, and 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) is one main homolog of PBDEs which exists widely in environmental samples and human tissues. Guiyu, a small town which located at Shantou district in the South China, is the largest dissembling and processing center of electronic waste in China and even the world, where PBDEs are detected extensively in various environmental medium. Selenastrum capricormutum, Daphnia magna and Xiphophorus helleri are the representative organisms of different trophic levels in aquatic ecosystem. The toxic effects of BDE-47 and the lixivium of the environmental samples from Guiyu on Selenastrum capricormutum, Daphnia magna, Xiphophorus helleri were studied in the present study.The results showed that BDE-47 was middle-toxic to Selenastrum capricornutum, the 96h EC50 was 2.18 mg·L-1 in BDE-47 exposure. With the increase of exposure concentration of BDE-47, the chlorophylla a content decreased gradually in Selenastrum capricornutum cells, the content of GSH had slight variances among different treatments groups, and GST, APX and CAT activity increased firstly and then inhibited gradually. On the contrary, MDA reduced firstly and then increased steadily. The activity of SOD was almost suppressed continuously. Both APX and SOD were sensitive and suitable to be used as potential biomarkers for the exposure of BDE-47 compared with the other parameters.BDE-47 was high-toxic for Daphnia magna, the 48h LC50 was 1.04 mg·L-1. With the increase of exposure concentration of BDE-47, the activity of SOD and GST were induced firstly and then inhibited. Both SOD and GST expressed sensibility, but GST is comparatively more sensitive than SOD for the BDE-47 exposure. The chronic test of BDE-47 to Daphnia magna indicated that the length was inhibited, the fecundity was inhibited at the low concentration groups, however, the contrary performance were observed at high concentration groups. The eggs production number of the first time and the total egg production number are the most sensitive parameters for the chronic test of BDE-47.BDE-47 was high-toxic for Xiphophorus helleri. The 96h LC50 was 2.75 mg·L-1. GST and EROD were induced significantly when BDE-47 level was at only 0.02 mg·L-The content of GSH was decreased after 72h and 168h, and reached the lowest value after 168h. With the increase of exposure concentration of BDE-47, CAT activity was induced firstly and then inhibited. On the contrary, it was reduced firstly and then increased gradually for MDA. MDA and EROD were the more sensitive measured parameters and more suitable be used as potential biomarkers for BDE-47 exposure.The contents of GSH and MDA of tested aglae had slight variances among different treatments groups with lixivium derived from Guiyu soil and sediment samples. With the increase of exposure concentration of the lixivium, both SOD and GST activity were increased. The activity of CAT reached the lowest at the concentration of 100% of the lixivium of the soil and sediment. The activity of GST was almost suppressed continuously after the exposure of the the lixivium of the sediment, but the activity of GST was reduced firstly and then increased with the concentration increased of the lixivium of the sediment. APX and SOD were sensitive and suitable to be used as candidates potential biomarkers for the exposure of BDE-47 compared with the other parameters.The chronic test of the lixivium to Daphnia magna indicated that the fecundity were inhibited at all concentration groups, and was embodied in the parameters of the frequency of production and the total egg production number. SOD was increased firstly and then reduced after the 24h exposure of the lixivium, and there was no significant change after 48h exposure. GST was suppressed continuously after the exposure of the lixivium. On the contrary, the content of MDA was above the control group. Both GST and MDA were sensitive and suitable to be used as potential biomarkers for the exposure of BDE-47 compared with the other parameters.