Characterization Of PBDEs In Typical Lakes And Reservoirs In North And Northeast China

Due to their low cost and superior flame retardant qualities,polybrominated diphenyl ethers（PBDEs）,a class of brominated aromatic compounds and typical POPs,are used as additive brominated flame retardants in a variety of industries,including paints,plastics,rubber,foams,textiles,and electronics.PBDEs are easily released into the environment during production,application,and disposal since they are added to items without chemical bonding.They have been found in a range of natural settings as well as in plant and animal tissues.Because of their bioconcentration and toxicity,PBDEs are difficult to totally breakdown in the environment,may also be transported over great distances and bioaccumulate and biomagnify in the food chain,and are hazardous to many systems after entering the human body.The ensuing health issues and environmental contamination are very concerning.The lives and productivity of the nearby urban population depend on lakes and reservoirs,which are significant freshwater resources and sources of drinking water in China.They also control the availability of drinking water.Freshwater resources are not distributed equally throughout China’s territory,with more than 80%of them being concentrated in its developed eastern parts while the north is experiencing a severe water crisis,particularly in north China region.PBDEs released into lakes and reservoirs with domestic and industrial wastewater are a constant threat to the ecosystem of the surrounding environment,especially the security of drinking water resources for nearby residents,along with the rapid economic development,increased human activities,and growing urbanization.Even though there are numerous studies on the pollution of PBDEs in lakes and reservoirs in China,the majority of them are focused in the industrialized regions of the southeast coast and the Yangtze River system,and there aren’t many comprehensive studies on the pollution of PBDEs in northern lakes and reservoirs.Therefore,this study chose seven typical freshwater lakes and reservoirs,including Baiyangdian Lake,Hengshui Lake,Nansi Lake,Songhua Lake,Xiaoxingkai Lake,Yuqiao Reservoir,and Guanting Reservoir,as the study area to examine the contamination characteristics of PBDEs in surface water and surface sediments of various lakes and reservoirs as well as the regional differences in the spatial distribution of PBDEs.The composition characteristics and potential sources of PBDEs congeners in the surface water and surface sediment of the lake reservoir were explored.The ecological risk assessment of PBDEs congeners in the surface water and surface sediment of the lake reservoir was performed.The partition coefficients of PBDEs in the aqueous-sediment phase were calculated,and finally the partition behavior of PBDEs between the aqueous and sediment phases was explored to predict.The following are the primary research findings and contents:（1）The contamination characteristics of PBDEs in surface water and surface sediment of seven typical lakes and reservoirs were compared.The detection characteristics of PBDEs in surface water and surface sediment were discovered to differ noticeably.Three lakes and reservoirs（Yuqiao Reservoir,Nansi Lake and Guanting Reservoir）detected more PBDEs in surface water than in surface sediment,one lake（Nansi Lake）detected as many PBDEs in surface water as in surface sediment,and three lakes（Baiyangdian Lake,Songhua Lake and Xiaoxingkai Lake）detected fewer PBDEs in surface water than in surface sediment.The surface water of Nansi Lake and the surface sediment of Baiyangdian Lake were found to contain the highest levels of total PBDEs,respectively.In general,the contamination levels in the surface water of Nansi Lake and Guantingl Reservoir were high,the contamination levels in the surface sediment of Baiyangdian Lake were high,and the contamination levels in the samples from the other lakes and reservoirs were all at moderate to low levels compared to the contamination of PBDEs in other studies conducted domestically and abroad.（2）Significant differences in the compositional characteristics of PBDEs in surface water and surface sediment,as well as significant variability between sampling sites in each lake reservoir,were found when the composition of PBDEs congeners in surface water and surface sediment in each lake and reservoir was analyzed.Although,the lower brominated BDEs（Mono-BDEs,Di-BDEs,Tri-BDEs,Tetra-BDEs,and Penta-BDEs）were generally the most predominant,Deca-BDEs predominated in the surface sediments of only a very small number sampling sites in Baiyangdian Lake and Hengshui Lake.When the findings of the principal component analysis are combined,the usage of PBDEs in the vicinity of lake and reservoir basins in North and Northeast China is complex,and the main potential sources can be divided into the following three categories:direct emissions from human activities,degradation of highly brominated BDEs,and transport of PBDEs in a variety of ways from other environments into the lakes and reservoirs.（3）Congeners of PBDEs found in the surface water and surface sediments of the lakes and reservoirs underwent an ecological risk assessment.The findings indicated that the mixture of Penta-BDEs in the surface water posed a significant ecological risk and would be detrimental to aquatic life in the lakes and reservoira.The ecological danger of Octa-BDEs mixes,in contrast,was low.Penta-BDEs in the surface sediments posed the greatest ecological danger,and all seven typical lakes and reservoirs had a medium to high ecological risk to sediment species.Moreover,Deca-BDEs pose a significant ecological risk in the surface sediments of Baiyangdian Lake.In addition,the environment is not much at danger from Tri-BDEs,Tetra-BDEs,Hexa-BDEs,or Octa-BDEs.（4）In seven typical lakes and reservoirs,the water-sediment partitioning characteristics of PBDEs were studied.There were both positive and negative correlations between PBDEs concentrations and DOC（TOC）values,but is only a highly significant positive association between Penta-BDEs in the surface sediments and TOC（p<0.01）.The partition coefficients of PBDEs in the aqueous-sediment phase were calculated,and it was discovered that the higher the K_TOC,the greater the likelihood that PBDEs would build up and settle in the surface sediments of this lake（reservoir）.