clean and clear

Determination of Sediment Phosphorus Concentrations in ST. Albans Bay, Lake Champlain:
Assessment of internal loading and seasonal
variations of phosphorus sediment-water column cycling

September 30, 2005

FORWARD

St. Albans Bay has been badly polluted by phosphorus loading for many years. Forming a plan to deal with this pollution has been a time consuming task because of the need to determine how the phosphorus gets into the water, how it interacts with the various currents and minerals in the bay’s sediments and whether the conditions in the bay allow for it to eventually flush itself out.

Two studies of the bay sediments, conducted in 1982 and 1992, suggested that phosphorus levels were declining, due in part to a major upgrade in sewage treatment. This meant it was possible that the bay might recover on its own. However, subsequent monitoring has shown that phosphorus levels have not declined over the years as expected. So, at the urging of the St. Albans Area Watershed Association, the Agency of Natural Resources used funding from the Clean and Clear Action Plan to update the research on phosphorus levels in the sediments.

Dr. Greg Druschel of the University of Vermont Geology Department conducted this research over the summer of 2004. The results of his study (71 pgs, 1403KB PDF) confirmed that there is still a substantial reservoir of phosphorus in the sediments which can be transferred into the water under certain chemical conditions and nourish algae blooms for many years to come.

What next? Given the results of the study, the Agency is considering whether to examine treatment options to control the internal phosphorus loading in St. Albans Bay as discussed in the Lake Champlain Phosphorus TMDL.

For more information, please contact:

Dr. Gregory Druschel, University of Vermont Department of Geology
Eric Smeltzer, Environmental Scientist, Agency of Natural Resources