The Effect of pH on the Release of Phosphorus from Potomac river Sediment 1987
- Published:
- November 1, 1987
- Originator:
- Chesapeake Bay Program
Recurring algal blooms in the tidal freshwater portion of the Potomac River indicate an association between chlorophyll a high phosphorus concentrations, and high pH of the water. In the present study, the release of phosphorus from sediments, as a function of overlying water pH was measured at eight locations. Phosphate release under aerobic conditions was found to increase as a function of overlying water pH. Between pH8 and 9 the sediment-water phosphate flux was low. Beginning with an overlying water pH in the range of 9.0 to 9.5, the phsophate flux increased. The increased release of phosphate at high pH is likely due to solubilization from iron and aluminum phosphate complexes. The rate of release of phosphorus from the sediments with an overlying water pH of 10 was similar to the amount of phosphorus necessary to account for the excess phosphorus in the bloom area.