Research On Environmental Behavior And Adsorption Removal Of Polybrominated Diphenyl Ethers In Sedimentary Column From The Anhui Section Of Huaihe River Basin

Polybrominated diphenyl ethers（PBDEs）have the characteristics of hydrophobicity,long-distance migration and biological toxicity,which can accumulate in organisms through the magnification of the food chain,posing a lasting threat to human health and ecological environment.Due to the low water solubility of PBDEs,it is easy to adsorb on suspended particles and eventually accumulate in sediments,so it is of great practical significance to study the pollution characteristics of PBDEs in sediments.In this study,three sedimentary column samples were collected from different locations in Anhui section of the Huaihe River Basin from August to September in 2021 to study the content,time distribution and composition characteristics of PBDEs,influencing factors and evaluate the ecological environment and health risks.In addition,the effects of adsorption time,solution initial p H and temperature on the adsorption behavior of decabromodiphenylether（BDE-209）on biomass charcoal were also investigated under the conditions of adsorption time,solution initial PBDEs and temperature,which provided new ideas and ways for the treatment of decabromodiphenylether pollution in soil and sediment.The main conclusions of this study are as follows:1.PBDEs monomers were detected in the sediments of Anhui section of the Huaihe River basin.The detected concentration of BDE-209 was 1～2 orders of magnitude higher than that of other PBDEs monomers.The total concentration range and average concentration of∑₉BDEs and BDE-209 were 0.04～6.1 ng/g（3.1ng/g）and 0.02～5.6ng/g（3.3 ng/g）,respectively.Compared with those at home and abroad,the pollution degree of PBDEs in the sediments of the study area is at a low level.2.The time distribution characteristics of PBDEs in sedimentary columns in different regions are basically the same,showing a rising trend as a whole.The results of correlation analysis between TOC,economic development level and PBDEs show that TOC plays an important role in promoting the increase of PBDEs content in sediments,and PBDEs is positively correlated with GDP and industrial GDP,reflecting that regional economic and industrial activities have a positive impact on the input of PBDEs.3.The ecological risk value of pentabromine and decabromodiphenyl ether in the sediments of the study area is much higher than that of other homologues,but the total ecological risk of PBDEs is in the low and middle level,and the impact on the ecological environment is limited.Health risk assessment shows that the health risk value of children is much higher than that of adults,but the health risk caused by PBDEs to residents in the study area is an acceptable level and will not affect human health.4.The adsorption process of BDE-209 on commercial plant ash can be divided into two stages:fast adsorption and slow adsorption.In the early stage of the reaction,fast adsorption occupies an absolutely dominant position,while in the middle and later stage of the reaction,slow adsorption gradually plays a leading role.From the whole adsorption process,the ratio of slow adsorption capacity to fast adsorption capacity is about 1:7,and the fast adsorption capacity determines the total adsorption capacity of the reaction.The adsorption process is fitted by the adsorption model,and the results show that when the p H is constant and the temperature is 25℃,the adsorption capacity of commercial plant ash to BDE-209 is 80%～89%of that at 5℃,which reduces the adsorption capacity,indicating that the adsorption process is an exothermic reaction.When the temperature is constant,p H=6 or 9,the BDE-209adsorption capacity of commercial plant ash is improved to a certain extent compared with the neutral condition,and the adsorption capacity in alkaline environment is more significant.