The Impact Of Oil Pollution On Microbial Activity Of The Liaohe Delta Typical Wetland

Liaohe Delta is the largest warm temperate coastal wetlands of Asia, with enormous environmental regulatory function, the ecological benefits and economic value. Due to human over-exploitation of wetland resources and pollutant emissions of land-based sources, wetland ecosystems are being destroyed, wetland area is shrinking, ecological environment is deteriorating, and ecological restoration of wetlands has become a common concern. The oil field development and other production activities result in heavily pollution of acres of land of Liaohe oil field and around the region, the petroleum also became one of major pollutants of the Liaohe River Wetland. Especially the rapid development of the oil industry in recent years, wetland destruction caused by oil pollution is increasingly serious, and control of oil pollution in Liaohe River Wetland needs to be urgently addressed.Microbial activity plays the most important role in transformation of organic matter of wetlands soil, and microbial populations and enzyme activities have a very close relationship with the degradation of petroleum contaminants of wetland soil. Taking soil enzyme as one of the indicators of soil quality assessment in the field of environment has become a hot research topic. In recent years, many scholars have used microbial activity to assess different types of oil-contaminated soil, but the impact of oil pollution of estuarine wetlands soil on microbial activity has relatively little research.Horizontal distribution of petroleum hydrocarbon pollution and the number of Hydrocarbon Degradation Bacteria (HDB) of Liaohe reed wetland in the summer and autumn and the number of HDB and soil enzyme activity of Liaohe reed wetland in the summer are studied in this paper. The results show that: the number of HDB in soil of summer is greater than the number of autumn, the soil concentrations of petroleum hydrocarbons in the autumn are higher than in summer, and the temperature, soil pH, total nitrogen content and total phosphorus content is the major factors of the number of HDB; soil in the region where reed grow better have a higher TPHs removal rate of petroleum hydrocarbon pollutants soil; the soil concentrations of petroleum hydrocarbons in 2010 are higher than in 2009, the numbers of HDB are higher than 10~6 /g; Dehydrogenase, catalase and lipase activities show a positive correlation with soil petroleum hydrocarbon concentration, and the Dehydrogenase is the most significant(r=0.924;p﹤0.01).The impact of oil pollution on the microbial quantity and enzyme activities of Liaohe delta typical wetland are also studied and the result show that, different degrees of oil pollution affect soil microbial quantity and enzyme activities differently: with the oil concentration of 1000μg/g, the two types wetland soil TPHs removal rate is more than 90%, when the oil concentration﹥﹦5000μg/g, the two types wetland soil TPHs removal rate are more than 70%; oil pollution stimulated reed wetlands soil microbial activity, but the number of HDB, catalase and lipase activities are inhibited in addition to dehydrogenase which is significantly increased; dehydrogenase activity could reflect soil microbial activity during the process of bioremediation of contaminated soils, and could be used as biological indicators of the extent of oil pollution of wetlands and removal of oil pollution.Experiments of the bioremediation of oil-contaminated soil of Liaohe wetland have found that: aboriginal microbe was one of the main ways of removal of oil pollutant of wetland soil; Staphylococcus pasteuri secreted higher lipase activity, and played a catalytic role in removing the oil pollutants of soil when it was non-rhizosphere environment, where the removal rate of soil TPHs was from 77% to 82%; planting reed significantly promoted the degradation of oil pollutants of wetland soil, and promoted the removal rate of soil TPHs from 77% to 86%.