title: A simple model for predicting aluminum bound phosphorus formation and internal loading reduction in lakes after aluminum addition to lake sediment.
abstract: The conversion of mobile phosphorus (P) to aluminum bound P (Al-P) after addition of Al to over 300 sub-samples from 35 sediment cores collected from 20 lakes in the upper Midwest, United States was investigated in this study. Consistent relationships between mobile P reduction and Al-P formation were detected across a broad range of mobile sediment P contents (0.04-2.8 g P m(-2) cm(-1) or 0.083-2.8 mg P g(-1)DW) and lake types. The conversion of mobile P to Al-P was dependent on the initial mobile sediment P content and the amount of Al added to the sediment. An empirical model was then developed to predict the formation of Al-P based on the amount of Al added relative to the initial mass of mobile P in the sediment. The results were compared to sediment collected from an Al treated lake and good agreement was found between the model and in-situ changes to sediment P fractions caused by Al treatment. The model developed in this study, unlike previous models with extreme, singular endpoints, allows for a continuum of estimates for mobile P conversion to Al-P, along with efficiency of P binding by Al, as Al dose varies. Model results can be used in conjunction with mobile sediment P based predictions for internal P loading to calculate an Al dose required to meet internal phosphorus loading goals for lake management and restoration without the need for expensive, time consuming Al additions to sediment.
authors.affiliation: Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment, Box 7050, 75007 Uppsala, Sweden. Electronic address: brian.huser@slu.se.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Huser
authors.affiliation: Barr Engineering, 4077 77th Street, Minneapolis, MN 55304, USA. Electronic address: kpilgrim@barr.com.
authors.forename: Keith M
authors.initials: KM
authors.lastname: Pilgrim
mesh_terms: D000535:Aluminum / Q000737:chemistry*; D004784:Environmental Monitoring / Q000379:methods*; D019015:Geologic Sediments / Q000737:chemistry*; D060106:Lakes / Q000737:chemistry; D008910:Minnesota; D008956:Models, Chemical; D010758:Phosphorus / Q000737:chemistry*; D013023:South Dakota; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D014874:Water Pollutants, Chemical; D010758:Phosphorus; D000535:Aluminum
keywords: Aluminum; Internal loading; Lakes; Mobile phosphorus; Sediment; Sorption