The U.S. Army Corps of Engineers Philadelphia District announced Thursday that the harmful algal bloom status at Blue Marsh Lake in Bern Township has been downgraded from a warning to an advisory.
The Army Corps oversees the lake and park, which spreads into Penn and Lower Heidelberg townships.
It had closed the swim beach at the Dry Brooks Day Use Area of the lake on Aug. 26 and advised visitors to avoid any contact with the lake water because of high levels of blue-green algae in the water, which can be toxic.
“The update in status does not eliminate the risks associated with harmful algae,” said the statement released Oct. 28. “Please be aware of the presence of moderate levels of blue-green algae in the lake and the potential for harmful toxins to be present. Visitors are advised to be alert for harmful algal bloom conditions and to avoid contact with discolored water or scum.”
Blue-green algae, or cyanobacteria, can multiply quickly in warm water and create toxins that are harmful to people and pets.
A Corps spokesman had said the algae blooms occur every summer at Blue Marsh Lake and that they are a result of the agricultural uses of the land surrounding the park, runoff and significant amounts of rain.
The Corps said it has been working with the Pennsylvania Department of Environmental Protection to conduct sampling and testing at different locations at the lake.
