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Health Dept. Issues Advisory for Harmful Algal Blooms

Be on the lookout for harmful algal bloom this summer.

As the weather heats up this summer, the Putnam County Department of Health is alerting residents about harmful algal blooms, also known as “HABs.” They arrive when temperatures soar, presenting a serious health hazard for residents and their pets when swimming, boating or just cooling off at the water’s edge.

For the last two years, HAB detections have been observed at 20 of Putnam County’s 32 regulated bathing beaches.

“Our county is home to many beautiful and serene lakes, and we are aware that algal blooms are a concern for residents,” said County Executive Kevin Byrne. “Our community health assessment has identified this as a top 10 challenge. With the warming weather, this is not unexpected, and it is a problem statewide and beyond.”

Shawn Rogan, environmental health director at the department of health, said many algal blooms are harmless and, in fact, serve an important role in the aquatic food chain.

“However, some species produce toxins that are harmful to both people and animals,” he said. “In our freshwater lakes, HABs are usually cyanobacteria, more commonly known as blue-green algae. These bacteria are usually present in low numbers. When nutrient levels rise and warm temperatures occur, the algae reproduce rapidly to form blooms. This increases the toxin levels in the water and can pose a risk if toxins are ingested, inhaled, or simply through skin contact.”

Public Health Sanitarian Vincent Perrin explained that blue-green algae can take on different looks.

“They may appear like scattered green dots or long streaks,” he said. “Sometimes they look like pea soup or spilled paint. They may even simply appear as a blue-green or white discoloration to the water.”

Sometimes it is hard to tell a HAB from other non-toxic green algae blooms. As a result, the health department and the New York State Department of Environmental Conservation recommend avoiding all discolored water, floating mats or scums. To become more familiar with the look of these blue-green algae blooms, an HABs photo gallery can be viewed at

Understanding when and where HABs are most likely to occur improves monitoring and reporting these blooms to the health department. Many factors contribute to blooms, in addition to seasonal warm weather.

In Putnam, which has several areas with a high density of homes around lakes, the runoff from fertilizers and septic systems can contribute to increased nutrient levels – particularly phosphorus and nitrogen – in lakes. This local factor feeds algal growth.

Residents are advised not to go in any water that appears discolored.

“If you see what you think might be a HAB in or on the water, stay out and keep any pets away, as well,” said Rogan. “Tell the lifeguard, a staff person or the beach operator.”

HABs on public beaches can also be reported directly to the health department by calling 845-808-1390.

The health department regulates all public beaches. Annual inspections and water testing ensure that facilities are operating according to public health law. The department posts beach closures online daily. Closures become necessary not only when a HAB occurs, but also if coliform bacteria levels rise above a safe level.

Closure notices can be viewed at

“Remember, HABs can vary in color, from blue-green to white or yellow,” said Perrin. “Another HAB characteristic is that they can come and go very quickly. They can also seem to disappear, so that a beach with a HAB in the morning may look clear by afternoon, but unsafe toxin levels may still exist.”

If there is potential exposure, to people or pets, interim Health Commissioner Dr. Michael Nesheiwat advises rinsing with clean water as soon as possible.

“If exposure does occur and symptoms follow, you should consider medical attention,” he said. “Symptoms may include nausea, vomiting or diarrhea; skin, eye or throat irritation; and other allergic reactions or breathing difficulties.”

In addition to consulting a healthcare provider, the health department should be informed as soon as possible.


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