Orthophosphate adsorption by cedar wetland soils in northern lower Michigan

TitleOrthophosphate adsorption by cedar wetland soils in northern lower Michigan
Publication TypeReport
Year of Publication1987
AuthorsWetzel PR
Pagination15 pp.
InstitutionTip of the Mitt Watershed Council

Research on emergent wetlands suggests that cedar wetlands have the potential to improve water quality individually or collectively by removing orthophosphate (phosphate) from water draining a watershed. This work compares phosphate adsorptive abilities between the soils of nine cedar wetlands in northern lower Michigan. Soils were tested at three different phosphate concentrations to determine a possible sorption saturation point. Wet soil was placed in beakers containing phosphate solutions. After four hours the solutions were filtered and the phosphate was measured colorimetrically with a spectrophotometer. A two-way, mested ANOVA was used to test for the variance of soil adsorption between the wetland sites, between initial phosphate concentrations, and within wetland sites. The overall mean of phosphate adsorbed for all wetland sites and initial concentrations was 90%. The 0.05 confidence interval fell between 87 and 93 percent. Phosphate adsorption between and within wetland sites varied significantly. Soils adsorbed similar percentages of phosphate at all the initial concentrations tested, indicating that no saturation point was reached.