Cumulative Environmental Impact Of Pollutants On Dalian Bay

In this paper, we researched cumulative environmental impacts of pollutants on Dalian bay. As a dynamic space, off-shore area not only has a diversity of coasal zone resources and natural geography characteristics of sea and land interactions, but also has a distinct social and economic feature. Due of the rapid development of economy, the off-shore area has been severely affected by wastes from busy production activities around coastal regions.Firstly, production activities were investigated and analysed to identify the main cumulative impact sources around Dalian bay. Further more, in order to explore and research cumulative impacts on the gulf, we used the way of cause and effect assay chart to analyse these sources, and then chosed cumulative impact indicators which are water and sediment of Dalian bay. For water, cumulative situation of degradable pollutants are mainly discussed, and for sediment, the situation of heavy metals are mainly analysed.Secondly, a soft of Vensim was used to construct a model of system dynamics of water to research cumualtive impact of degradable pollutants.In the model, three indexs of degradable pollutants COD, TN and TP and oil were mainly traced, of which sources and changes were discussed in detail, and the cumulative situation of water was also assessed. According to simulation results, the cumulative value of oil is the highest, which illustrates that the cumulation of oil has the most serious impact on Dalian bay compared with others. The comprehensive cumualtive value of water began to overstep the principle critical value 1 from 2003 in Dalian bay. That is to say, to some degree, the water quality has been affected because of the cumulation of pollutants of water. In the end, three scenarios were seted to predict cumulative conditions of water of Dalian bay in 2020.Finally, a method of index of Geoaccumulation (Igeo) was used to analyse cumulative situations of heavy metals in sediment of Dalian bay. In this part, four types of heavy metal selected were discussed in detail, and results show that cumulation sequences are Cd> Pb> Zn> Cu. Based on further analysises, we found that cumulative sources of heavy metals mainly are industrial solid wastes dumped into gulf from enterprises around Dalian bay, also, reasons of change conditon of heavy metals are the mixed action of the rapid economic development and industrial structure of enterprises in Dalian.