Harmful Algal Blooms
The Swimmable ShoreRivers program works with government health agencies at the local and state levels to monitor toxic algal blooms and inform the public of serious potential health risks to humans and pets. Algal blooms occur naturally in the summer, but increased levels of nutrient pollution in our waterways from fertilizers, septic systems, and wastewater plants fuel larger, more toxic, and longer-lasting blooms.
In the ShoreRivers region, toxic blooms occur most frequently on the Sassafras River due to its lower salinity levels. Due to the severity of toxins in the water, the Maryland Department of the Environment frequently has to issue water contact advisories for the river or its tributaries.
ShoreRivers’ monitoring shows that algal conditions vary based on location, weather, and other factors, making systematic, scientific analysis vital.
In the summer of 2020 the Sassafras River experienced the longest, largest, and most toxic algal bloom every recorded on the river. Here is an update from Sassafras Riverkeeper Zack Kelleher in week two of what ended up being a ten week bloom.
