Preliminary Study Of Pollution, Degradation And Remediation In Aquatic Ecosystem Of Yellow River Delta Wetland

In recent years, extensive attention to wetland pollution, degradation, ecological restoration and protection of wetland has arised in domestic and international scholars. Yellow River delta wetlands, as the central interaction of land and oceasion, is more liable to be influenced by human activities due to its ecologically sensitive and fragile traits. At presnet, a range of issues such as pollution, degradation and reduction of ecological function hace occrued in this region. This research, oreinted to aquatic ecosystems of the Yellow River delta coastal wetland, is targetd to investigate and critically evaluate the current pollution of aquatic ecosystem, analyse and assess the feature and process of aquatic ecosystem degradation and the process of reed wetlands restoring from pollutant. The main outcomes of this research shows below:1 The pollution status and quality evaluation of aquatic ecosystem in Yellow River delta coastal wetlandThe water quality of Yellow River delta coastal wetland was mild eutrophication and deteriorated, by the main pollutants incuding:TN, TP, NH4+-N, UIA and petroleum. The mainstream and static water areas are polluted slightly, while branches such as Guangli River, Shenxiangou River, Tiao River and Chao River are polluted seriously. COD and DIN are the main factors that incur the obvious eutrophication in costal water areas. The sediments of surface suffered in mild pollution by nitrogen and phosphorus, midium heavy mentle pollution, poteitial threat from Hg,Cd, regional oil and polychlorinated biphenyls (PCBs). The marine creature in wetland is facing the pollution of Pb and Cr with excess of 100% degree.2 Evaluation of aquatic ecosystem degradation in Yellow River delta coastal wetlandYellow River delta coastal wetland has a tendency of recession through the analysis of its current ecological feature and functional condition in in three dimensions of biology, physics and chemistry. In Physical perpective, natural wetland area reduced sharply and the diversity of landscape decreased; In view of Biology, biodiversity, amounts of creatures and production shows a tendency of shrinking yearly. Moreover, changes occur in biological communities and ecosystems structure. From chemical view, issues are organized as freshwater wetlands, water environment pollution of coastal waters, soil pollution, biological pollution and soil salinization. According to AHP to construct multi-level evaluation index system through the relationship between each component, the results indicated that Yellow River wetland is suffering from slight general degradation which degree is not high, but has presented the overall degradation trend, and this trend will not cease in a short period. Agricultural reclamation, terrigenous pollution, oil industry development, excessive ultilization of the wetland resources, biological invasion, storm surge, rising sea level are summarized as the main factors causing the degradation of wetlands.3. Ecological restoration of Yellow River delta coastal wetland:the preliminary research of purification of reed wetlandsApplying black box rule, reed wetland which save and restoration more complete in the Yellow River delta National Nature Reserve are studied, respectively, to conduct monitoring of pollutants interception and estimating ability to purification of natural and artificial reed wetland system. The results showed that, the removal efficiency of the total nitrogen (TN), ammonia nitrogen (NH3-N), nitrate nitrogen (NO2-N), total phosphorus (TP) and phosphate of natural reed wetlands were 24.495, 13.190,2.238,0.824 and 0.353 mg/(m2·d) respectively, then the total nutrient removal of reed wetland in Reserve was estimated,138.7 t of TN,4.7 t of TP,74.7 t of NH3-N,12.7 t of NO2-N can be removed during irrigation every year. The removal efficiency of TN, TP. COD of artificial reed wetland were 42.415,0.786,78.793 mg/(m2·d), respectively, artificial wetland removal efficiency was significantly higher than natural wetland. According to data analysis and experimental investigation found that measures cuncluding strengthen pollution control; ecological water supplement and construction of protected area are the most effective and can get restoration results immediately.