title: The contribution of roadside soil to phosphorus loading in the eutrophic Lagos Lagoon, Nigeria.
abstract: Roadside soils were sampled from the Lagos Lagoon catchment during the wet and dry seasons over the period 2005-2009. Lagoon sediment samples were also collected within the same period. All samples were digested with aqua regia to determine total phosphorus and extracted with 0.5 M sodium bicarbonate to determine the bioavailable fraction (Olsen-P). A segmented flow analyser method was used for analysis and good accuracy was demonstrated for two reference soils (SO-2 from CCMET and SRM 2711 from NIST). The Lagos Lagoon is a hypereutrophic water body (1270 ± 1170 μg P L(-1)), with significant areas of anoxia and water hyacinth growth. The total phosphorus concentrations in roadside soils (16 sites; mean ± 2 S.D.) were 285 ± 279 mg kg(-1) in the wet season and 424 ± 629 mg kg(-1) in the dry season, indicating that rainwater leaching is a major source of phosphorus in the lagoon. The bioavailable fractions were 5.17 ± 3.47 mg kg(-1) (2.1 ± 1.5% of the total) in the wet season and 13.0 ± 8.7 mg kg(-1) (4.3 ± 4.5% of the total) in the dry season.
authors.affiliation: Department of Chemistry, University of Lagos, Lagos, Nigeria.
authors.forename: Akeem
authors.initials: A
authors.lastname: Abayomi
authors.forename: Malcolm
authors.initials: M
authors.lastname: Nimmo
authors.forename: Claire
authors.initials: C
authors.lastname: Williams
authors.forename: Kehinde O
authors.initials: KO
authors.lastname: Olayinka
authors.forename: Bola
authors.initials: B
authors.lastname: Osuntogun
authors.forename: Babajide
authors.initials: B
authors.lastname: Alo
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Worsfold
mesh_terms: D004784:Environmental Monitoring; D005068:Eutrophication; D005618:Fresh Water / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry; D009549:Nigeria; D010758:Phosphorus / Q000032:analysis*; D012621:Seasons; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*; D014186:Transportation / Q000706:statistics & numerical data; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D010758:Phosphorus