Studies On The Discharging And Distribution Of Heavy Metal Pollution In The Pearl River Delta

Statistical and field monitoring data were used to study the discharging and spacial distribution of heavy metal of the Pearl River Delta area (simplified as PRD area) and Dongguan City, respectively. At the same time, the reason of this distribution and its damage on the ecological environment were discussed. Finally, suggestions and solutions on these problems were proposed.After 20 years drastic economic development, the Pearl River Delta, once the economic ordinary area of the country, has rank the first of China's economic developed area. Meanwhile, the cumulated environment problems have revealed themselves. The problems, which occurred in this area, will also happen in those so-called economic-catching-up areas of China. In this case, reflections on the gain and loss of the Pearl River Delta in the past 20 years will benefit other developing areas of China today. The paper focused on the heavy metal, the persistent trace toxic pollutant, which closely related to the daily life of local people.Innovations of the paper include:Integrate the study of heavy metal pollution with industrial development and government strategy on economy for the future. Cluster method was used to select the critical cities and industries for the discharging of heavy metal. Scenario analysis was performed to give the picture of heavy metal pressure on local environment in the next 10 or 20 years. Then, a so-called trace-back-to-market method was used to calculate the economic loss from heavy metal discharging in the PRD area. (Based on the statistical data)For the field monitoring data, 1) geostatistic method was used to analyze the scope, pollution sources, am'sotropism of the pollutants. Isoline picture and trend picture of soil heavy metal were plotted and, combined by GIS (Geographic Information System) method and Kriging method, the areas of ecological regions were calculated. All this convenience in analyzing spacial data, which characterize the variogram and Kriging method of geostatistics, are the weakness of average value method and general statistics. 2) principal factor method as well as environment knowledge were used to analyze the reason for the spacial differentiation of soil heavy metal. 3) the value of loss of ecological service capacity was also calculated by Kriging method. Finally, conclusions were got from the former study:First, discharging amount of heavy metal in PRD area reached its highest point in 1998, again, after experiencing a slump in 1999, rose in 2000. Since 2000, PRD area has become the main source of heavy metal discharging of Guangdong Province.Second, sources of Pb were along the rivers and roads; Cr, which sources mostly located along the rivers, was mainly caused by human activity; sources of Cd and Cu concentrated in the waterside area which were characterized by heavy pollutant industries; high value place of Cu located in Qingxi township, where the electronic industries were prosperous, reflect a strong influence of such industries.Third, the reachable and effective distance of pollutant source of heavy metal is 30km.Forth, the distribution of heavy metal in upstream area and south mountain area were mainly influenced by the use of pesticides and chemical fertilizer. Meanwhile, the vegetable land in south mountain area were also dominated by electroplating industries, which was the most important factor for the heavy metal distribution in farmland in the middle-transition area, where the vegetable land were influenced by smelting industries.Fifth, the environment loss of Guangzhou and Jiangmen, caused by discharging of heavy metal, was more than other cities of PRD area. A drastic decline of environmental loss was found since 2001, after a mild decline since 1999.Sixth, loss of ecological service capacity caused by Cd pollution and heavy metal total pollution were 4,700,945$/a and 4,700,945$/a respectively.