Water samples were collected from the Potomac River on Thursday, 2/21/2002 by the Maryland Department of the Environment and examined for algal concentrations by the Maryland Department of Natural Resources. The samples continue to show elevated concentrations of the potentially harmful algae, Dinophysis accuminata at concentrations up to 46,000 cells/liter. Elevated concentrations (greater than 5000 cells/liter) have been found from the Route 301 bridge over the Potomac River downstream to Ragged Point. Presence of Dinophysis in the water column has been detected downstream as far as Point Lookout. The U.S. Food and Drug Administration reported on Friday, 2/22/2002, that no toxins were found in a test of one algae sample collected on 2/15/2002 from the Potomac River. Additional algae and toxicity testing will be conducted this week.

For the latest information on the temporary closure of shellfish waters on the Potomac River, please visit the Maryland Department of Environment press release. The presence of the alga also led Virginia officials to close Virginias Potomac River tributaries south of the Route 301 bridge to shellfish harvesting, including the Little Wicomico River. Please refer to our Maryland DNR Harmful Algal Blooms web page on Dinophysis for additional links and information about the alga.