NJDEP Develops Color-Coded Public Health Alert Index For HABs

Just in time for lakes reopening Memorial Day weekend, the New Jersey Department of Environmental Protection has (NJDEP) rolled out a color-coded health alert index for recreational activities in freshwater lakes impacted by harmful algal blooms (HABs). 

According to NJDEP, the index released May 21 makes it clearer to the public that boating and related activities in some instances may still be permissible when lower levels of HABs are detected.

HABs can vary in severity from lake to lake and even within individual lakes so alert levels may vary from location to location, depending on conditions, particularly in large lakes such as Lake Hopatcong, Greenwood Lake and Spruce Run Reservoir in northern New Jersey, stated NJDEP.

Recreational Activities

The index touted by NJDEP would provide a more refined guidance for recreational activities. For example, swimming, water skiing, paddle boarding and kayaking are not recommended during a bloom due to the greater probability of ingestion. 

Secondary recreational activities such as boating, canoeing and fishing carry less levels of risk because the potential of ingestion or immersion in water is less likely to occur. At no time is it recommended to eat fish caught in a waterbody during a harmful algal bloom or drink water from it.

The index is part of a response initiative by Gov. Phil Murphy following nearly 40 HABs that impacted New Jersey in 2019. This initiative includes more than $13 million in state funding for local projects to mitigate and respond to HABs as well as development of tools to enhance monitoring and communications of health information to the public.

Chart Development

The chart was developed after a series of meetings Murphy and NJDEP held with impacted communities starting in November 2019 as part of its efforts to map out a better path moving forward. 

“We can’t predict with certainty when HABs will occur, but with this enhanced communication and color-coded alert index, we hope that the appropriate responses to HABs will become much more predictable and targeted, which should provide much more certainty as well as flexibility for residents and businesses to make sensible decisions,” said NJDEP Commissioner Catherine McCabe in a press statement.

The color-coded alert index with signage provides greater precision on recreational use recommendations for impacted water bodies based on levels of cyanobacteria and/or cyanotoxins present, according to NJDEP. The index has multiple alert categories, each providing recommendations of activities that should not be pursued based on water monitoring results.

Watch Level

A Watch will be posted when cell counts exceed 20,000 cells to notify the public of potential less serious health effects and allow them to make informed decisions about their recreational activities. 

Alert Level

The Alert level is for public bathing beaches only and is indicated when a HAB has been confirmed, with cell counts between 40,000 and 80,000 and no known toxins above the public health threshold. At the Alert level, the index suggests beaches increase monitoring for future toxin production.

Advisory Level

An Advisory will be posted when cell counts exceed 80,000 cells or when toxin levels exceed 3 micrograms per milliliter of microcystins. An Advisory will be issued if toxin production occurs at or above 3 micrograms per milliliter of microcystins, even if cell counts are below 80,000.

Warning, Danger Levels

The Warning and Danger tiers are designed to communicate HABs that are producing very high levels of toxins which justify additional caution. NJDEP stated New Jersey has experienced approximately a dozen HAB events over the last three years that would trigger a Warning; monitoring has never indicated a HAB event which produced toxins that would trigger a Danger alert level.

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