Phosphorus in tributaries to Lake Mälaren, Sweden: analytical fractions, anthropogenic contribution and bioavailability.
Riverine phosphorus (P) concentration and P-transport to Lake Mälaren, the third largest lake in Sweden, has been monitored for 35 years in 12 major tributaries. During a period of 15 months, complementary assessments of particulate P, suspended matter and dissolved reactive P were made. Particulate P comprised 64%, dissolved unreactive P 23% and dissolved reactive P 13% as flow-weighted means, with high seasonal variability. "Background" or "reference" P-transports in the streams were estimated by different methods and the anthropogenic contribution to P-transport was shown to be reduced over time. Potential algal availability of particulate P showed a mean availability of c. 45% for water draining arable and forested land, while the availability was higher for sewage discharge particulate P and algal P. Calculated total bioavailable P in tributaries was shown to equal reactive P measured on coarsely filtered water and it was indicated that the proportion of bioavailable P was higher during the period with high anthropogenic P-contribution than with a lower contribution.
Persson
G
G
Department of Environmental Assessment, Swedish University of Agricultural Sciences, Box 7050, SE-750 07 Uppsala, Sweden. Gunnar.Persson@ma.slu.se
D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D056890:Eukaryota / Q000378:metabolism; D005618:Fresh Water / Q000737:chemistry*; D006801:Humans; D010316:Particle Size; D010758:Phosphorus / Q000032:analysis* / Q000493:pharmacokinetics; D013535:Suspensions; D013548:Sweden; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014876:Water Pollution / Q000517:prevention & control
D013535:Suspensions; D014874:Water Pollutants, Chemical; D010758:Phosphorus