Pollution Characteristics And Risk Assessment Of Phthalate Esters In Typical Lake Of Xinjiang,China

As a common plasticizer and fragrance regulator,phthalate esters(PAEs)are widely used in daily life and chemical production.And the combination of PAEs and other substances is through physical action.They are easy to enter the environmental media under high temperature and high pressure conditions,thus causing harm to the environment.Bosten Lake and Ulungur Lake are two typical lakes located in the south and north of Xinjiang,both of which play an important role in breeding and animal husbandry.At the same time,they are also important national ecological reserves.Therefore,in this study,the concentration of PAEs in water and sediment of Ulungur Lake and Boston Lake in dry and flood periods was determined by gas chromatography-mass spectrometry(GC-MS),the pre-treatment conditions were selected,the temporal and spatial distribution characteristics of PAEs were analyzed,the source of PAEs was explored,and the correlation between the concentration of PAEs and physical and chemical properties of water and sediment was analyzed.And carry out ecological risk assessment.The main research results are as follows:(1)After the selection of a variety of extractants and extraction times,the pre-treatment method that n-hexane: dichloromethane(1:1,V: V)was used as the extractant and extracted for three times,then purified by HLB column solid phase and eluted by n-hexane: dichloromethane(1:1,V: V)was determined.(2)The detection of PAEs concentration found that PAEs existed widely in water and sediment,and the concentration of ∑PAEs was higher in dry season than in flood season.DMEP and DEHP,DBP and DMEP are the main PAEs in the water and sediment of Ulungur Lake,respectively.DBP and DIBP,DBP and DAP are the main PAEs in the water and sediment of Bosten Lake,respectively.Compared with the pollution level of PAEs in other water and sediments at home and abroad,the pollution level of PAEs in Ulungur Lake and Bosten Lake is at a moderate level,and the pollution level of PAEs in Bosten Lake is greater than Ulungur Lake.Principal component analysis and statistical analysis showed that PAEs came from domestic pollution and chemical production.According to the correlation between the concentration of PAEs and physicochemical properties of water and sediments in Ulungur Lake and Bosten Lake,the effect of the concentration of PAEs on physicochemical properties was more serious in dry season than in flood season.(3)According to the spatial distribution,the ∑PAEs in Ulungur Lake during dry season showed that the pollution in the area that rivers enter the lake was less than that in other areas,which was contrary to the distribution in flood season.The ∑PAEs of Bosten Lake in dry period showed that the pollution distribution in the area that the river enters the lake was greater than that in other areas,which was contrary to the distribution in flood period.The ∑PAEs in sediment of Ulungur Lake in dry season showed higher pollution concentration where the Ertysi River enters the lake and where the villages are dense.In flood season,the concentration of Kuyergat River enters the lake was lower.The ∑PAEs in the sediment of Bosten Lake was lower in the dry season,while the ∑PAEs in the flood season showed that the pollution in the river inlet area was greater than that in other areas.(4)The ecological risk assessment of PAEs in water and sediment was carried out by risk commercial method and effect range-low method respectively.The results showed that the risk of DEHP was high,DBP and DIBP had moderate risk,and the ecological risk of DEP and DMP was low.DIBP is seriously polluted in the sediment of Bosten Lake during the dry season,which poses a threat to the ecological environment,while other PAEs are not threatened temporarily.The environmental risk situation of PAEs in the water and sediment of Ulungur Lake and Bosten Lake is still severe.It is urgent to implement the abandonment,limitation and replacement of PAEs chemicals according to the local development and environmental pollution situation.The results of this study are helpful for relevant departments and scholars to understand the PAEs pollution in the water and sediment of typical lakes(Ulungur Lake and Bosten Lake)in Xinjiang,providing data support for related studies and data reference for lake environmental protection.