Mosses As Indicators For Monitoring Atmospheric Heavy Metal Pollution In Wuxi,China

Bryophytes have simple structure, which is benefical to accumulate heavy metals from air.They are effective biomontiors for estimating atmospheric heavy metal deposition.In thisstudy,monitoring of atmospheric deposition of six heavy metals(Cd,Cr,Cu,Ni,Pb and Zn) usingterrestrial moss samples was carried out in the Wuxi Region, Jiangsu, China. For this purpose,Haplocladium microphyllum and H. angustifolium were selected as the biomonitors and the mosssamples were collected from49sites by means of systematic sampling. The spatial distribution ofsix heavy metals was analysed based on the moss data.Moss bags made of Sphagnumjunghuhnianum were used to monitor the pollution of five heavy metal elements (Cd,Cu,Pb,Vand Zn) in four roads. The influence of traffic flow on the atmospheric heavy metal pollution wasanalyzed.The main results are as follows:(1) No significant correlation was observed between the heavy metal concentrations inHaplocladium and soils. It was obvious that soil substrate had little effect on the heavy metalconcentrations in mosses, coinciding with the opinion that mosses absorb heavy metals mainlyfrom atmospheric deposition. Bryophytes are suitable biominitors for monitoring atmosphericheavy metal pollution.(2) Using contamination factors (CF) as the evaluation index,the evaluation system of thepollution level for six heavy metal elements（Cd、Cr、Cu、Ni、Pb、Zn）in Wuxi wasestablished.Once the content of heavy metal elements was obtained, the pollution level can beevaluated.(3) The total pollution coefficient was calculated for all sampling sites to identify theseriously polluted areas and slightly-polluted areas of heavy metals in Wuxi.(4) Using Geographic Information with Kriging algorithm, the spatial distribution of heavymetal deposition for each element was presented. Based on the moss data, the spatial distributionof six heavy metal elements associated with air pollution was analyzed.(5) The accumulation ability of S. junghuhnianum changes with heavy metals. Theconcentrations of heavy metals in S. junghuhnianum was topped by Zn, followed by Pb, Cu, Cr,and V, indicating the metal enrichment capacity of S. junghuhnianum in descending order was Zn,Pb, Cu, Cr, and V.(6) Moss-bag technique was applied to monitor the atmospheric heavy metal pollution offour roads in Wuxi.The pollution degree of four roads in descending order was Tongjiang Avenue,National Highway No.312, Fengbin Road, Minfeng Road and Hui hill, coinciding with thevehicle flow.The greater the vehicle flow is, the more serious the atmospheric heavy metalpollution is.Vehicle flow has direct influence on the heavy metal pollution level.(7) The moss-bag monitoring result showed that atmospheric heavy metal pollution of thefour roads in winter was more serious than that in summer.(8) The correlation between the heavy metal concentrations in S. junghuhnianum and thevehicle flow indicated the close relation between them. Vehicle flow has important effect on the heavy metal pollution level.