Swimming at Spruce Run Reservoir in Hunterdon County, New Jersey, has been banned for the summer due to harmful algal blooms. State officials announced the closure on Thursday (July 4), citing health risks posed by the blooms.
Harmful algal blooms, or HABs, are a growing global problem and have been detected in various levels in New Jersey lakes this year, according to the state Department of Environmental Protection. The level of toxins in the water at Spruce Run is currently above the public health threshold, indicating a moderate risk of adverse health effects.
Spruce Run, a popular destination for swimming, fishing, and boating, has previously experienced harmful algal blooms, leading to swimming closures in 2021. The reservoir is the third-largest in New Jersey, boasting 1,290 acres of water and 15 miles of shoreline for recreation.
HABs occur when algae colonies grow and produce toxins that can harm people, fish, marine mammals, and birds. Most of the blooms in New Jersey are caused by cyanobacteria, also known as blue-green algae, which naturally occur in fresh water. In sunlight and hot weather, cyanobacteria can reach harmful levels, forming toxic blooms that resemble blue or green paint spilled into the water.
Exposure to cyanobacteria can cause rashes, allergy-like reactions, flu-like symptoms, stomach issues, and irritation of the eyes or respiratory system. Drinking the contaminated water can lead to more serious health issues, including liver damage and neurological problems.