کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4409684 | 1307500 | 2013 | 9 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Phosphorus partitioning between sediment and water in the riparian wetland in response to the hydrological regimes Phosphorus partitioning between sediment and water in the riparian wetland in response to the hydrological regimes](/preview/png/4409684.png)
Water quality in watersheds is severely impacted by nutrient enrichment as a result of agricultural activities. Understanding hydrological effects on P dynamics can optimize the ecological function of riparian wetlands to reduce nonpoint source pollution. The XiaZhuHu wetlands were selected for field P investigation, and two typical hydrological batch studies of 35 d each (a static column observation simulating the dry season, and a steady-flow flume observation simulating the rainy season) were conducted to understand sediment P dynamics and evaluate capacity of P immobilization. The average equilibrium P concentration of 0.02 mg L−1 among the 31 sampled sediments was generally lower than the average dissolved reactive P concentrations in the overlying water, indicating an ecological role as a P sink. In static simulation observation, there was a fast-pace sorption process during the first 3 d followed by a slower paced process, and the mass of P adsorbed per unit sediment surface (MPAS) reached 0.16 mg cm−2. The temporal curves of P equilibrium between flowthrough water and top sediment (5 cm) were characterized as a quasi “V”-pattern, and the MPAS ranged from −0.04 to 0.46 mg cm−2 during the steady-flow observation. The newly-trapped P was mainly found in Al-bound P and subsequently as Fe-bound P, which would be helpful for sediment P immobilization. Based on our findings, the sediment of the tested wetlands could retain external P from agricultural land by as much as 10–30 times the area of itself, which accounts for approximately 3.3–10% of the watershed area.
► Sediment acting as an ecological role of P sink mainly depends on EPC index.
► P entrapment by sediment during dry and rainy seasons reached −0.04 to 0.46 mg cm−2.
► Riparian wetland may retain P from agriculture soil by 30 times the area of itself.
► 3.3–10% of watershed area is suggested for wetland to balance agricultural impact.
Journal: Chemosphere - Volume 90, Issue 8, February 2013, Pages 2288–2296