The Human Health Assessment To Phthalate Acid Esters (PAEs) And The Photometric Characteristics Of Chromophoric Dissolved Organic Matter In Erlong Lake

Erlong Lake is the receiving water body of industrial sewage discharge in Liaoyuan city upstream,and has been playing a variety of functions such as flood control,irrigation,aquaculture,drinking water,power generation and tourism.The monitoring method of lake water environment using remote sensing technology is developing rapidly.Colored dissolved organic material（CDOM）is the colored fraction of dissolved organic matter（DOM）,which has a profound effect on underwater light penetration as CDOM strongly absorb slightly in the blue and UV region,and can be conducted by remote sensing technology fastly.Phthalates esters（PAEs）are a class of important organic compounds,which are often added into polymer systems as plasticizers.Due to their wide application,they have become the most common pollutants worldwide.This study selected the priority control toxic pollutions of dimethyl phthalate（DMP）,diethyl phthalate（DEP）,butyl phthalate（DBP）were listed by the US National Environmental Protection Bureau（EPA）as the research objects,we studied the temporal and spatial distribution,sources and human health risks of phthalates at 25 monitoring sites.This article takes Erlong Lake as research object and using fluorescence regional integration（EEM-FRI）technology to determine the components and sources of CDOM.The main content was to analyze the correlation between CDOM absorption characteristics,fluorescence characteristics,water quality parameters and PAEs.And through outside measure and laboratory experiment obtains three periods data.Morever,we studied the optical properties and sources of CDOM and the correlation between CDOM and PAEs in Erlong Lake.Meanwhile,the human health risk assessment of three target phthalate ester homologues in Erlong Lake was studied.The main research results are as follows:（1）The absorption of CDOM in aqueous phase showed obvious differences in different periods.Through the relationship of S_275-295和E_250:365 in three water season was wet water season>average water season>low water season,The relationship of SUVA₂₅₄ was low water season>average water season>wet water season we found that in the dry water season,the aromatic compounds and high-molecular weight fulvic acid components of CDOM in the water of Erlong Lake account for a relatively large proportion.Further CDOM was greatly affected by the input from land source.In wet water season,the precipitation effect has dilute the aromatic components and high-molecular weight fulvic acid components of CDOM in Erlong Lake.Therefore,there were more autochthonous organic matters,and the organic matters with higher degree of humus from terrestrial sources were reduced,meanwhile,the degradation ability of microorganisms was enhanced and a large number of small-molecular weight organic matters were produced.（2）The mean value of FI₃₁₀ in the three water season was greater than 0.8,and the value of FI₃₁₀ in wet water season was higher than that in low water season and average water season.Due to the high microbial activity in June,there were more CDOM from biological sources.Through ArcGIS spatial analysis,it was obvious that more autochthonous CDOM from microbial activities during the three water season in the south of Erlong Lake.The mean value of fluorescence index FI₃₇₀ in Erlong Lake was less than 1.4 in the three water season,and the CDOM in the water was mainly from terrestrial sources.According to the spatial analysis characteristics of fluorescence index using ArcGIS,the source of CDOM in the water of Erlong Lake is mainly affected by land use type,precipitation and human activities on the shore.（3）The fluorescence components in erlong lake were mainly terrestrial components R3（fulvic acid substances）and R5（humic acid substances）.Morover,fluorescence intensity accounted for 60.41%（June 2017）,70.02%（October 2017）and51.34%（May 2018）of the total fluorescence intensity,the value of P_（3+5）in low water season is higher than that in wet water season and average water season,furthermore,in low water season,terrestial CDOM accounts for a large proportion in Erlong Lake.（4）According to the the relationship between water quality parameters and fluorescence components.We found that DOC components in the water body are mainly derived from soluble microbial metabolic by-products and phytoplankton degradation products,and a small part of them are derived from terrestrial sources such as sewage and agricultural fertilizer residues in soil runoff.In general,the main components of CDOM in Erlong Lake are autochthonous tryptophan and microbial protein by-products,as well as terrestrial fulvic acid and humic acid organic compounds.The composition and distributions of CDOM were impacted by the environmental factors such as freezing,precipitation,sewage discharge,agricultural wastewater and aquatic plants.（5）The mean concentrations of DBP detected in the present study was well above the reference dose(RfD:3μg L^-1)regarded as unsafe by China for surface water（Environmental Quality Standard for Surface Water of China,GB3838-2002）.However,there were significant relationships between∑3PAEs and R3（R²=0.88,p<0.001）,R4（R²=0.89,p<0.001）.In surface natural water,PAEs account for a part of CDOM absorption.This experimental result provides the correlation between PAEs and FRI fluorescence components of CDOM.It provides a basis for the rapid and accurate monitoring of water quality by remote sensing,and lays a theoretical foundation for quantitative water quality monitoring and health risk assessment based on remote sensing technology.（6）The health risk assessment was performed for Erlong Lake.For two exposure pathways in three water seasons,the risk index（HI）of phthalates at 25 sampling sites in Erlong Lake was all less than 1,and the PAEs with the highest contribution rate to non-carcinogenic health risk of PAEs pollutants were all DEP.The research of CDOM optical properties in water is an important content of water color remote sensing research,contribute to the analysis the relationship of the components of CDOM,relative molecular weight and the source,and build the correlation of CDOM-PAEs,is the precondition for the implementation of the fast and exact monitoring water quality remote sensing,in order to quantitative water quality monitoring and health risk assessment based on remote sensing technology to lay the theory foundation.