Method And Application Of Monitoring Atmospheric Heavy Metals Pollution By Mosses In Huai’an City

The mosses are small,and their sensitivity to heavy metals in the atmosphere is higher than that of the seed plants because of their special structure.As recognized indicators of air pollution,they are often used for monitoring and assessment of heavy metal pollution in various regional environments.In this thesis,18 mosses around Hongze Lake were collected,and nine heavy metal elements such as Cu,Zn,Pb,Cd,Cr,Ni,Co,V,and Mn,as well as three non-heavy metal elements such as Al,Fe,and Ba were determined by ICP-AES and ICP-MS.It was described that the enrichment analysis and cluster analysis based on heavy metal contents in mosses.The suitable species for monitoring heavy metal pollution in the local atmosphere were recommended.At the same time,the calibration factors of 18 other mosses based on the heavy metal contents of Haplocladium microphyllum were calculated and further supplemented so that the method of monitoring atmospheric heavy metals in a single moss species can be improved.The contents of twelve metal elements were measured in the H.microphyllum that is common in the Huai’an City by the grid point method(15 km×15 km,50 squares).Correlation analysis and cluster analysis were carried out on the metal contents.The spatial distribution maps of twelve metal elements were drawn by Arc GIS software.The settlement and pollution of atmospheric heavy metals in various counties of Huai’an City were analyzed,and the potential ecological hazards of nine heavy metals were evaluated.The main results of this study were listed as below.1.Analysis of metal contents of European moss standard samples(M2 and M3).The variation between the obtained and recommended concentrations in M2 and M3 was found to be less than 15%,indicating that the precision of ICP-AES and ICP-MS is quite high and ensuring the accuracy and consistency of the analytical instruments between the laboratories.2.Monitoring mosses and their type classification.18 species,14 genera,and 9 families of mosses were collected and identified around the Hongze Lake.The Pottiaceae were the dominant family.Five new record species of Jiangsu Province were found,such as Barbula indica,Trichostomum planifolium,Brachythecium campylothallum,Dicranella varia,and Entodon divergens.Analysis of metal contents in mosses showed that 18 mosses had the most significant effect on the accumulation of Cu and Zn.According to the enrichment characteristics of mosses,18 mosses can be divided into four types: enrichment mosses,exclusion mosses,enrichment/exclusion mosses,and general mosses.It is recommended to use a wide range of enrichment and general mosses for monitoring atmospheric heavy metals pollution in this region.3.Estimation of calibration factors for metal contents of different monitoring mosses.According to the concentrations of twelve metals contained in H.microphyllum,the calibration factors of eighteen mosses in Hongze Lake area were calculated.4.Determination of metal contents in fifty samples of H.microphyllum.The median size order of the twelve metal elements is: Al>Fe>Zn>Mn>Ba>Cu>V>Cr>Pb>Ni>Co>Cd.5.Analysis of spatial distribution and element correlation of metal elements.The“Huaiyin-Qingjiangpu-Huai’an-Lianshui” urban circle is the most polluted.The correlation coefficient of Cd-V is the highest.In addition,Ni has significant or extremely significant positive correlation with other 11 elements.Mn and Cr have significant or extremely significant positive correlation with other 10 elements.6.Evaluation of heavy metal pollution in Huai’an City.Cd is the most important ecological risk factor.The pollution is the most serious in Qingjiangpu District.The highest ecological hazard is Wudun Town and the lowest Huangji Town.This thesis recommends the suitable moss species for monitoring heavy metal pollution in Huai’an City,which makes up for the lack of monitoring of single species and expands the scope of moss monitoring.At the same time,cluster analysis,correlation analysis and potential ecological risk analysis are carried out to accurately assess the status and trends of heavy metal pollution in the atmosphere,and we provide a theoretical basis for monitoring and controlling atmospheric heavy metals in Huai’an City.