Algae toxins threat to health

Wednesday, Aug. 20, 2008

The high algal toxin levels were discovered by the Maryland Department of Natural Resources and the Morgan State Estuarine Research Center from the boat piers at Sweden Point Marina on Mattawoman Creek in Smallwood State Park in Marbury to Maryland Point on the Potomac River in Nanjemoy, said Olivia Campbell, DNR spokeswoman. The Charles County Department of Health issued a warning about the algae blooms last week.

Contact with the toxic algae could cause gastrointestinal illness or skin irritations in humans and could be fatal to livestock and pets. State health officials advise people to not swim or boat where the algal blooms are evident and to not get the water in the mouth, eyes, nose, ears and throat.

‘‘Excessive nutrient pollution in the water fuels the growth of the algal blooms, which are not uncommon in the fresh water and low salinity waters of the Potomac River,” said Tom Parham, DNR’s tidewater ecosystem assessment director, in a press release. ‘‘Harmful algal blooms such as these can be prevented if more people living in the Potomac River watershed take steps to reduce runoff pollution.”

The area where people put boats in the water at Sweden Point was posted to warn of the danger of coming into contact with the algae blooms, said Bill Leebel, health department spokesman.

‘‘Our main concern is that folks keep themselves and their pets out of the water,” he said Monday. ‘‘The blooms hug the shoreline and once they hit brackish water the salt level kills the algae.”

No reports of human or pet illness from coming into contact with the algal blooms have been reported to the health department, Leebel said, adding that there were no blooms reported in local waterways last summer.

Some easy methods to help cut back on the pollution that causes the algal blooms include planting native trees and rain gardens, using rain barrels and not fertilizing lawns and gardens in the spring, Parham said.

State biologists were in Charles County on Monday to monitor the impacted areas of the creek and river, said Kara Turner, DNR spokeswoman, adding that the algal blooms were at a much lower level in the Potomac River.

Microcystis aeruginosa is a naturally occurring alga in the tidal freshwater and low salinity brackish water areas of the Chesapeake Bay and Maryland coastal bays, according to DNR officials. Large blooms occasionally occur in the warmest months of the year.

The alga detected in the Mattawoman and Potomac River is one of 700 species that may be found in water samples that are collected from the Chesapeake Bay.

Boaters and swimmers are asked to stay away from the blooms, which resemble thick mats that coat the water so heavily that you cannot see your hand an inch below the surface, according to state biologists. In calm waters, it might look like spilled green paint on the water’s surface.

If the algae is blown by wind or pushed by currents into higher-salinity waters where it cannot survive, it takes on a greenish-yellow color and a chunky appearance until it dies.

In the algae comes into contact with the skin, wash it off with fresh water. If skin irritation persists, state health officials advise that people should contact a doctor.

The state also warns that people should not eat the internal organs of fish that are caught in the areas where there are algal blooms.

Large blooms can kill fish and shellfish because they deplete the water of oxygen, according to DNR’s Web site. Algae can remove oxygen through normal respiration at night or through the decomposition process as the blooms die and in those situations there might not be enough oxygen in the water to support fish or shellfish in the vicinity.

State biologists have conducted a Chesapeake Bay monitoring program to examine algae density and distribution throughout the year in the main stem of the bay and its tributaries since 1985, according to DNR officials. Information collected during the monitoring process is analyzed with water quality data to better understand the environmental factors that contribute to algal blooms and insure that proper management actions are taken to reduce the severity of future blooms.

State biologists will continue to sample the water and monitor the blooms in the Potomac River and Mattawoman Creek, Leebel said.

‘‘Blue green algae is in the water all of the time at very low levels,” he said. ‘‘This is one of those things, an environmental phenomenon, that occurs when all of the variables, warm weather and high phosphate levels from fertilizers and human and animal waste fall into place. The state wants to continue monitoring the blooms until they disappear.”