Study on characteristics of migration and variation of water pollutants in Daqing wetalnd

Wetland research has been the research hotpot both in domestic and at abroad in recent years,Pollutants migration and transformation law of wetland water is still not very clear.The wetland has a larger area in Daqing regional,but oil field produced water and industrial and domestic wastewater discharged release to the wetland environment,which had significant impact on the water environment of Daqing wetland.Thus,The study of self-purification efficiency of wetland water and its changing condition has important significance to reveal the change of ecosystem health.Therefore,the water sample,phragmites austral of wetland plant and wetland soil were collected at different typical location(the inlet,the outlet,intermediate position) in different seasons.The change of water quality,plants and soil under the conditions of different spatio-temporal patterns were investigated.The results showed that the pollution degree was he most seriously in Summer,The order of pollution degree was SummerAutumnSpring.The lowest comprehensive pollution index was 13.11 in spring.The highest comprehensive pollution index was TN with 14.05.The order of comprehensive pollution index of five water quality index was TNCOD Mineral oil NH4+-N BOD5.The water contaminate removal mainly occurred in the front area of wetland.In monitoring period,TN removal of anterior region accounted for about 71.86% of total region in the wetland,COD removal of anterior region accounted for about 77.51% of total region in the wetland,NH4+-N removal of anterior region accounted for about 56.46% of total region in the wetland,Mineral oil removal of anterior region accounted for about 79.91% of total region in the wetland.BOD5.removal of anterior region accounted for only about 56.46% of total region in the wetland.Pollutants removal in the wetland systems declined along the water flow direction,and the self-purification of wetland was better.A series of studies on the role of plants and soil indicated that the plants removed the nitrogen and phosphorus directly by absorption,and this process performed better in the growing season of plants.The plants on the foreside of the wetland grew better than those grew on the rearward,and they can also absorb more nitrogen and phosphorus.This regulation was accorded with the one that the pollutants removal declined along the water flow direction.In addition,wetland soil adsorbed some pollutants of water body.In a word,plants and soil of wetland play important roles in the pollutants removal of wetland water.