Research On The Environmental Impact At The Marine Dumping Site For Dumping Dredged Material In The Estuary Of Zhanjiang

During this two decades, along with the reform and opening up as well as the rapid development of economic construction, as the major temporary spoil ground on the coast of Leizhou Peninsula, Zhanjiang temporary spoil ground is bearing vital environmental stress because of increasing frequency of dumping activities of dredged materials. Since the dredged materials into the oceans increase, it is necessary to consider the impact of dumping activities on spoil grounds as well as surrounding areas in order to protect marine environment from serious damage.In this assay, in the light of environment monitoring and management reality in spoil areas, in accordance with the work tasks in Zhuhai marine environment monitoring center, and on the basis of material collection, field investigation and monitoring, the monitoring materials of Zhanjiang temporary marine spoil ground in Zhuhai marine environment monitoring center in 2009~2010 are adopted to conduct the research on water depth, and the changes of the ocean water, sediments as well as marine biological environment in Zhanjiang temporary marine spoil ground as well as surrounding areas, and discussion is made on the impact of dumping activities on the marine environment. The conclusion is shown in following major aspects:1) The evaluation factors of sediments in all monitoring marine areas accord with the first-grade standard of the marine sediment quality, and the overall monitoring marine sediment environment maintains in a favorable state. According to the analysis results, the pollutant contents of sediments maintains a light change, and dumping activities do not pose negative impact on the sediment quality in the spoil area as well as its surrounding areas.2) In the sea water in the temporary spoil ground, inorganic nitrogen content exceeds the forth-grade marine water quality standard, and in terms of other monitoring factors, except some station with exceeding the standard, all accord with the first-grade marine water quality standard. Through the comparative analysis on the monitoring factors before, in and after the dumping activities respectively, in is found that all water quality monitoring factors maintain slight changes on the concentration, with content of some factors decreasing to a certain degree. Except that the monitoring results of the content of the inorganic nitrogen exceeds the first-grade standard because of its high background value, all others accord with the requirement of the first-grade standard. The analysis supports that dumping activities do not pose any impact on the water quality in this marine area basically.3) According to the analysis on the monitoring results, fishes as well as mollusks in the monitoring marine zone maintain a favorable biological quality state, all evaluation factors is within the first-glass value of the shellfish regulated in the national standard of Marine Biological Quality.4) In regard to the water depth, the comparative analysis is conducted on the water depth change in the spoil ground, indicating that, the water depth change is not obviously in the spoil ground and dumping activities do not cause obvious sludge to the marine areas at present.5) Cholorophyll a shows a slight change on its average content in monitoring marine zone, and marine primary productivity is affected by dumping activities to a certain degree in the marine areas.In sum up, monitoring results in various environment zones indicate a favorable water quality in monitoring zones and the environment state in areas surrounding the spoil area keeps good.