July 15, 2004 Tolchester Beach (Kent Co.) and Potomac River algal bloom updates.

Maryland Department of Natural Resources (DNR) and the Academy of Natural Sciences (ANSERC) identified blue-green algae that are widespread above the Route 301 Bridge to Mattawoman Creek (Potomac River) on July 6 but levels of Microcystis were typically below 10,000 cells/ml (Figure 1). Two exceptions were samples collected by ANSERC at the Mattawoman Boat Ramp (13,000 cells/ml Microcystis) and on the mainstem Potomac near Wellington Beach (30,000 cells/ml Microcystis) during routine water quality monitoring. Colonial Beach, VA, on the Potomac River had blue-green blooms that led to a beach closure before the July 4th holiday, however, the beach reopened July 3 with measurements of low algal concentrations.

In Kent County, Maryland, Department of the Environment field personnel collected a water sample from a blue-green algal bloom located off of Tolchester Beach on July 8. A slick of algae was noted in the mainstem Chesapeake Bay from Worton Creek down to the region of Tolchester Beach (Figure 1). The water sample contained 1,178,678 cells/ml Microcystis and has been sent to Wright State University for microcystin toxin testing; results are pending.

Bush River, Sassafras River, Middle River, Gunpowder River and Seneca Creek
were regions of blue-green blooms identified in May and June this year have no new bloom samples detected this month through July 14. Otter Point on the Bush River still had signs posted last week providing cautions about contact with blue-green algal bloom waters. There are no beach closures in Maryland due to blooms at this time.

Pockets of blue-green algal blooms may be encountered during boating and other recreational activities. People should take common precautions to reduce the risk of illness or discomfort related to blue-green algal blooms:

• The public should not swim in areas where a blue-green algae bloom is evident.



• Do not drink water from any area with the appearance of a blue-green algae bloom.



• If contact is made with problem water, simply wash off with fresh water.
  In some cases, skin irritations may occur after prolonged contact. If irritations persist, see a physician or local health care provider.



• Keep pets and livestock away from bloom areas.
  Blue-green algal blooms may contain toxins that could be harmful or fatal to pets and livestock.



• Do not eat viscera (internal organs) of fish caught in bluegreen bloom waters.



• Inhalation exposure to blue-green algal bloom waters may result in irritation of the eyes, ears, nose and throat with extended recreational activity on such waterways.

Please note that illness associated with harmful algal blooms is now a reportable illness so physicians should be reporting these to local health departments. The MD DNR in coordination and cooperation with DHMH and MDE will continue to monitor all blue-green algal 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