The blue-green algae bloom that has persisted on the Sassafras River since July 17th is showing signs of decline. The latest laboratory results received this week for samples collected on August 21st at Betterton Beach were positive for microcystin toxin but toxin levels were at their lowest level since July 22nd (Figure 1).

Figure 1. Time series of microcystin toxin results for Sassafras River samples, summer 2003.

Blue-green algal concentrations were 12,700 cells/ml on September 4th for Betterton Beach. This was the third consecutive sampling that recorded less than 100,000 cells/ml (Figure 2). However, aerial investigations on August 28th still showed evidence of surface scum accumulations of blue-green algae with predictably high bloom concentrations in the water immediately north and east of Betterton Beach (Figure 3).

Figure 2. 2003 History of Blue-green counts and toxin results on the Sassafras River.               +Tox = positive toxicity test for microcystin.

The Maryland Department of Natural Resources will continue to monitor all Microcystis blooms throughout the state. For up to date information on all of Maryland's harmful algal blooms and water quality, please visit Eyes on the Bay.

Figure 3. Surface accumulations evident along the shore of Sassafras River about 1 mile east of Betterton Beach. August 28th, 2003. Photo by Hunter Harris, Aloft Inc.