Environmental Characteristics And Management Systems Of Soils And Dusts From Shanghai Urban Areas

Human activities, in general, exert a substantial impact on the environment. In particular, population and industrial center in the urban area pollute the air, water and soil, causing a decline in the quality of the environment. Under urbanization, the quality of urban soils and dusts and the effects of ecology and environment are the important parts of urban ecosystem and human health, and the basis of management on urban continuable development, during the extending of urban area. So the research on distribution,transportation and effect factors on nitrogen,phosphorus and heavy metal from urban soils and dusts is a hot issue on the urban ecosystem.The present study focuses on the urban area of Shanghai, reporting the pollution sources, main contamination elements and the environmental situation of urban soils and dusts. Nitrogen, phosphorus and heavy metal contaminations of the environment have been and continue to be a world wide phenomenon that has attracted a great deal of attention from governmental and regulatory bodies anxious to prevent further environmental deterioration and to assess the potential health risks, which can be the basis to protect the urban ecosystem and human health. The following conclusions can be drawn:(1) In order to identify patterns in the spatial distribution of soil and dust variable, it is essential to present soil and dust survey data in the form of a map. Mapping contamination distribution allows immediate appreciation of the change in the contaminant with space and enables identification of areas that may contain hazardous concentrations. Knowledge of the spatial distribution of a contaminant is essential for site assessment and any subsequent risk assessment. Kriging is a spatial prediction method, which is designed to minimize the estimation variance and has the desirable feature of providing a measure of the uncertainty associated with predictions. It is an advanced field to research urban soils and dusts contamination by connecting Kriging and the ecological situation of Shanghai.(2) Nitrogen and phosphorus concentrations were used as the input data for a grid-based contouring map, to study the distribution of nitrogen and phosphorus in urban soils and dusts. The software used for the geochemical mapping was SURFER7.0. A geostatistics method called Kriging was adopted for the interpolation of geographical data. By using this, a serious difference for nitrogenand phosphorus from urban soils can be shown, because of the raw material and anthropic influence, and there were obvious difference on urban dusts, which is the result of the long distance transportation and human activities. The physio-chemical parameters in soils and dusts were the primary factors controlling the concentrations and spatial distribution of nitrogen and phosphorus.(3) This study also used information from the Langmuir-isotherm equation to describe the chemical mechanism of P-sorption reactions by soils/dusts. A series of laboratory experiments was carried out to quantify physical and chemical factors that control the level of soluble P in urban soils and dusts. As variations of pH is known to have a little influence to the adsorption and desorption process of P. For the water-to-soil/dust ratio, higher water-to-soil/dust ratio can lead to the decrease of desorption concentration, which meets the power isotherms. The phosphate desorption-absorption kinetic charcterictics can reflect the situation of urban water systems and the risk of human health.(4) The sources of the different elements in urban soils and dusts are typically common to most urban environments (traffic, heating systems, industry, natural substrate, etc), but their intensities and patterns of distribution vary accordingly to the peculiarities of each city. In the case of Shanghai urban area, traffic and industry activities are the important sources of heavy metal pollution. The physical and chemical factors, such as pH, grain size and TOC, control the level of trace element in urban soils and dusts. From the analysis of the correlation...