Cyanobacteria Harmful Algal Blooms
Conducting monitoring, public communication and educational outreach efforts.
Cyanobacteria are normal natural components of freshwater ecosystems found around the world but when water conditions are right, they can grow out of control and form surface blooms. These blooms are variously referred to as cyanobacteria harmful algal blooms, CyanoHABs or cyanobacteria blooms.
Perform a self-risk assessment prior to recreating can keep you, your family and your pets safe. There are two steps to a self-risk assessment. First, visually evaluate the water prior to recreating, looking for any discoloration or unusual growth. Second, check our resources to stay informed about active blooms across the state.
Cyanobacteria blooms can be harmful to pets, livestock, wildlife and people. Cyanobacteria can cause both acute and chronic illnesses. Acute effects, such as skin and mucous membrane irritation, can occur after short-term exposure. Chronic effects such as liver, kidney and central nervous system damage can occur from ingesting impacted water over a long period of time.
Cyanobacteria Plan Prevention and Remediation
Report an Illness
If you or someone in your family (including pets) becomes ill or develops a rash after recreating at one of New Hampshire’s surface waters, you should first consult with your doctor. You can then submit a detailed report to help us track waterborne-related illnesses. You can also check out the Center for Disease Controls fact sheets about cyanotoxin exposure for health care providers and veterinarians.
Drinking Water Exposure
In response to the growing concern about the public health risks of cyanobacteria and the increase in reported bloom occurrences in New Hampshire waterbodies, NHDES Drinking Water Bureau now offers grants to help public water systems implement programs to monitor for potentially harmful cyanobacteria blooms. Additionally, NHDES’ CyanoHAB Response Protocol for Public Water Supplies provides guidance regarding how to respond should a bloom occur within a surface waterbody used as a public drinking water source. General information about cyanotoxins in public drinking water supplies can be found through the EPA.