Affiliations: State Key Laboratory of Environmental Aquatic
Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy
Sciences, Beijing 100085, China | Department of Water Sources and Environmental
Engineering, China University of Geosciences, Beijing 100083, China
Abstract: Wetland systems in headstream watersheds are important to control
the nonpoint source pollutant phosphorus. Experiments were conducted using
intact sediment-water columns obtained from the multipond system in Liuchahe
watershed of Chaohu Lake to determine its capacity to retain P. It was found
that pond sediments had strong P retention ability. For the Hill pond, Village
pond and Rice pond, their retention coefficient (A) were 288.3, 279.2 and 260.8
L/m^2, respectively. The equilibrium P concentration
(EPC_w) were 0.016, 0.028 and 0.018 mg/L, respectively. The
Hill pond indicated the highest P retention ability. P retained in the pond
sediments indicated high stable degree. P removal from the overlying water
column into the pond sediments followed a first-order kinetic model. Under the
experimental hydrological conditions, the retention time had a positive
correlation with the P loading. The multipond system could provide enough
retention time to retain P in drainage runoffs. At the P levels evaluated, the
sediments of the multipond system are effective sinks to retain P from nonpoint
source runoffs.
