| Bryophyte is a widely accepted plant as environmental indicator because of its unique structure and physiological feature. Many countries and regions in the world have used bryophyte to indicate and monitor the environmental changes. The Yangtze River Delta is one of the six city belts in the world with rapid economic development. Its environmental quality and change has caused peoples attention increasingly. For better understanding the quality and changes of environments in region of the Yangtze River Delta, the moss Haplocladium plants as the experimental material were widely collected from different sides in central cities of Shanghai, Nanjing and Hangzhou as well as adjacent areas. In addition, the historical specimens of samples of Haplocladium were also collected from the herbaria. By means of ICP-OES analysis method, the contents of heavy metals Cd, Cr, Cu, Pb, Zn in Haplocladium plants collected from different sides and herbaria were determined. The data were analyzed by methods of Cluster Analysis and Kriging in order to indicate spatial and temporal distribution pattern of the contents of the heavy metals in the moss samples from different sides and times in the region. The main research results are as follows:(1) The heavy metal contents of Haplocladium plants collected from 27 sites in Shanghai were assayed and mapped based on the assay. The results showed that the heavy metal pollution in Shanghai was higher in the downtown and lower in the suburban. There was well correlation between the contents of heavy metals in the moss from different sides and the distribution pattern of industrial localities. The heavy metal pollution in Shanghai was increasingly heavier based on comparison of contents of heavy metals in the historical specimens collected during past 45 years. (2) Based on analysis of the heavy metal contents in historical and collected Haplocladium plants from Nanjing and by means of Cluster Analysis and Kriging method, the results indicated that the content of heavy metal in Haplocladium plants had great consistency with distribution pattern of industrial areas in city in Nanjing.. Analysis of the contents of heavy metal in the plants from 16 sites in Nanjing showed that it was higher in city center, busy traffic area and industrial zone and lower in suburban. In addition, the content of five heavy metals in recent five years in Nanjing has an overall reduced trend.(3) 25 sample sides in Hangzhou were set up and the heavy metal contents of fresh Haplocladium plants samples collected from different sides were determined. The results were analyzed by Cluster Analysis method and showed with isoline map. It also showed a feature that the heavy metal contents in city centre, heavy traffic zone were higher, and then extend to the industrial zone, and lower in suburban district.(4) The results of analyzing the heavy metal contents of Cr,Cd,Cu,Pb,Zn of ten cities in the regions of Yangtze River Delta implied that the cities such as Suzhou and Zhenjiang ,which are in the wake of developed industries and intensive industrial zone, have more serious heavy metal pollution than the other cities. Comparing with the recent years heavy metal contents in the plants from different times, it was found that the metal pollution presents a rising trend in most cities, but declined in Nanjing in 2010.This study provided a scientific basis for understanding the condition of heavy metal pollution and spatial and temporal changes in Yangtze River Delta. It is a first attempt to use bryophytes to indicate and monitor large-scale regional environmental quality and change in China. The results show that bryophytes can effectively indicate environmental pollution condition and changes in certain areas and certain time and provide a scientific basis for regional environmental protection with a wide foreground. |
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