The Distribution Characteristics And Assessment Of Semivolatile Organic Compounds In Groundwater In Different Areas

Groundwater is an important source of drinking water for human beings.With the increasing of human activities,organic contaminants have gradually become the most influential indicators.In this paper,the semi-volatile organic compounds(SVOCs)as target contaminants to research its distribution characteristics and status evaluation in different areas in groundwater,which can provide data support for groundwater pollution monitoring in the future,and provide evidences for groundwater protection.In this study,a total of 82 samples of pore water and karst water were collected from Hutuo River Pluvial Fan Plain in Shijiazhuang,the Pearl River Delta Plain in Guangzhou and the Kaste area in Qujing of Yunnan,and 102 SVOCs were tested in the laboratory,including polycyclic aromatic hydrocarbons(PAHs),pesticides,other industrial materials and products.The detection frequency and detection concentration of each area were analyzed with statistics methods.Using the isomer ratio method to determine the sources of pollution.The paper analyzed the reasons for the different occurrence of SVOCs in each area by combining properties of compounds.The results show:PAHs are mainly 2-4 rings in groundwater,and the detection frequency of Chrysene is highest(6.1%).The sources of PAHs pollution in Shijiazhuang are mainly caused by combustion.PAHs in Guangzhou could be caused by industrial pollution,and it is related to precipitation in Qujing.The most common pesticides in groundwater are methyl parathion and β-BHC.The detection frequency were 19.5% and 18.3%respectively,and the main distribution areas were Qujing and Guangzhou respectively.The most common type of other industrial material is 2,6-dinitrotoluene,and the detection frequency is as high as 65.9%.There were two indexs of SVOCs detected exceeding the standard,benzo(a)pyrene and aldrin with an exceeding rate,2.4%,and that samples are located in Shijiazhuang area.The three types of contaminants with detection frequency from high to low are industrial substances,pesticides,PAHs in groundwater in Shijiazhuang and Guangzhou.The concentration of pesticides is higher than that of industrial substances in Shijiazhuang.Pesticides are the main contaminants in Qujing.Guangzhou is heavily polluted by industrial contaminants.Both agricultural and industrial pollution in Shijiazhuang are heavy.Qujing is mainly polluted by agriculture activities.Organic pollution is closely related to population density and industrial layout in each area.The pollution status evaluation results showed that the pollution level was highest in Shijiazhuang,followed by Guangzhou,then Qujing karst area,and the proportions of above the medium-pollution areas were 37.03%,14.28%,and 0%,respectively.There are many contamination control factors in Shijiazhuang,and the contribution rates from high to low are industrial material--2,6-dinitrotoluene(90%),pesticides--aldrin(30%)and methyl parathion(20%),and PAHs--Benzo(a)pyrene(10%),all three types are shown here;the contribution rate of 2,6-dinitrotoluene in Guangzhou is 100%.In addition,the contribution factors are all pesticides in Guangzhou,mainly dimethoate,heptachlor,and BHCs;the contribution index of karst area in Qujing is mainly methyl parathion(67%).