Study On The Level And Distribution Of Organic Halogen Compounds In Water And Surface Sediments Of The Yellow River Basin

Polybrominated diphenyl ether (PBDEs), polychlorinated biphenyl (PCBs), organochlorine pesticides (OCPs), dechlorane plus (DP) and novel brominated flame retardants (NBFRs), which have been widely used or are still present in the commercial market, were discussed in this study. With their persistence and toxicity, PBDEs, PCBs and OCPs were banned in the whole world or some regions. DP was considered as replacement of Mirex and BDE-209, with increasing report about its persistence and toxicity. However, studies about NBFRs were rare. Not only evidences about NFBRs production information or toxicity but also studies about their levels and distributions in the environmental media were scarce. Recently, these organohalogened compounds were detected in almost all the environmental matrix, such as soil, sediment, water and so on, therefore, widely concern about their distributions and environmental behaviors were attracted worldwide.In this study, PBDEs, PCBs, OCPs, DP and NBFRs were analyzed in water and sediments of the Yellow River, which were collected from Qinghai-Tibet Plateau to estuary. Overall, levels of all the contaminant were lower than other study in China or other countries. Levels of PBDEs were affected by industry activities in the Yellow River, and the concentrations in remote districts were lower than developed regions. BDE-209 was the dominated congener in sediment, following by BDE-47 and BDE-99. The potential BDE-209 local emission sources in the Yellow River were found, and the degradation of higher brominated congeners might be the source of the other BDE congeners. Levels of PCBs in sediments fell in the range from 2.3 to 14.8 pg·g-1 d.w., which was lower than other regions both in China and abroad. PCBs concentration and the congener composition were significantly correlated with human activities. HCH, DDTs and HCHs were the dominated OCPs in the Yellow River. HCB and DDTs had no correlation with OC, suggesting a potential local source in the Yellow River. But concentration of HCHs was significantly correlated with OC, and β-HCH was the dominated isomer in this area. The evidences showed that HCHs in the sediments were caused by historical use. The ratio of p,p’-DDT and p,p’-DDE was greater than 1, indicating a potential newly input in the Yellow River region. HBB, PBBz and PBT were detected in most of the samples from the Yellow River. Because HBB emission sources in study area, and HBB concentrations were related to local industrial types. As PBBz and PBT were detected in background sites, which were sparsely populated, they could be considered as the potential persistent organic pollutants. Decabromodiphenyl ether (DBDPE) had a low concentration and the detectable ratio. DP concentration ranged from 1.11 to 10.47 pg’g d.w..fsyn, defined as the ratio of sys-DP and ∑DP ranged from 0.22 to 0.32, which was close to the value in commercial products. This result suggested that there were local DP sources in the Yellow River basin.Water samples that collected from the Yellow River were also analyzed. As same as the levels in sediments, PBDEs, PCBs, OCPs, DP and NBFRs in the water of the Yellow River were lower than other regions both in China and abroad. Composition of PBDE congeners was analyzed and we found that PBDE congeners were mainly affected by local emission. There were potential local emission source of BDE-209 in the Yellow River, as well as penta-BDEs. Similar congener composition of PCBs was found in water samples, which was dominated by PCB-118 and PCB-105. Longrange-transportation sources had a greater influence on PCB levels in remote sites. Levels of OCPs were increasing with the increase of altitude. There were local HCHs input in the whole area except for the Qinghai-Tibet Plateau, although different isomers were inputted in different area. There was newly input of DDTs in the Yellow River basin. HBB, PBBz and PBT were detected in water samples, and PBBz and PBT were similar in all the sampling sites. PBBz and PBT could be considered as the potential organic pollutants. DBDPE was only detected in the developed regions of Yellow River. With the limited detected ratio and low concentration, DBDPE was considered as a rarely used compound in the Yellow River. Despite of its low concentration, DP was detected in all the water samples, suggesting a widely use of DP in China. In this study, several organohalogened compounds, such as PBDEs, PCBs, OCPs and so on, were compared in tree bark, sediment and water that collected in 8 sampling sites of the Yellow River. Similar distribution was found between sediment and tree bark samples, while the distribution in water was complicated due to more environmental factors to water. The result suggested the equilibrium among different environment matrix of organohalogened compounds which had been banned, while point sources were the key factor to compounds which was still existed in the commercial market.