Following a release from the Lake Zoar Authority (LZA) appearing in The Newtown Bee's May 26 issue that generated some concerns on social media about possible health connections between blue-green algae blooms along the local waterway and amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease), Newtown Health District Director Donna Culbert sought clarification on the issue with state specialists.

Newtown, along with Monroe, Oxford, and Southbury, borders the 909-acre Lake Zoar, which also has hundreds of residential homes, and numerous beaches, boat launches, and recreational access points along its waterfront. Lake Zoar was created in 1917 by the construction of Stevenson Dam, Ms Culbert said.

According to the LZA release, exposure in high levels is a suspected cause of illness as severe as ALS in humans - a neurodegenerative disease - and can be fatal to pets and livestock. But Ms Culbert said the latest studies on the issue show no reasonable health outcome from exposure to the algae that is legitimately associated with ALS affection.

"With no reference to back it up, this statement [in the release] looks like a rumor," the local health official said. "As I understand from Chuck Lee at DEEP, Lake Zoar is one of the lakes that has a problem with nutrient load, and as such, these lakes are at greater risk for blooms. This is not new news."

The latest state guidance for local health officials regarding blue-green algae was just published on June 1, days after the LZA release, and was created in a cooperative effort between the DEEP and the state Health Department.

Algae Science

The report states that blue-green algae, also known as cyanobacteria, occur naturally in lakes and ponds throughout Connecticut, and are components of the aquatic food chain. In ordinary circumstances, cyanobacteria cause no apparent harm; however, warmer water temperatures and high nutrient concentrations may induce a rapid increase in their abundance.

This response is commonly called a "bloom," because algal biomass increases to the extent that normally clear water becomes markedly turbid. This tainted water takes on a green, blue-green, or reddish-brown colored hue. The report states that blue-green algae biomass can contain a mix of toxins, including skin irritants and potent liver toxins.

The Centers for Disease Control and Prevention (CDC) conducted a passive surveillance study tracking reports of human and animal morbidity and mortality for the US during the years 2007-2011. Dermal effects (e.g.; rash, itching, blistering) are the most frequently reported human health effect following direct contact with freshwater blooms, and GI/respiratory effects were also prominent.

For those recreating on or near an affected water body, the Connecticut report states the route of direct exposure to toxins from blue-green algae may be via ingestion, breathing, or contact with skin. Ingestion for this recreational scenario is possible when swimming.

Therefore, the report concludes, it may be necessary to take measures to block the oral and dermal potential exposure pathways by prohibiting swimming during a blue-green algae bloom. As ingestion of relatively large quantities of algae-tainted water can cause serious harm, pet owners should not let their pets swim in an algal bloom.

As algae blooms do not occur in groundwater, drinking water wells in the vicinity of the affected lake are not at risk of contamination from potential migration of the algal cells or toxins through groundwater into nearby wells.

Fish living in waters affected by a blue-green algae bloom may accumulate algal toxins in their muscle tissue and internal organs; however the health risk posed by consumption of such fish is uncertain.

Public Safety

Effective public notification and risk communication are important attributes during and immediately after a blue-green algae bloom. Posting closure signs at swimming areas and advisory signs at other access points used for public recreation is the primary intervention.

If an algal bloom event is evident, then Health District officials have the authority to close an impacted beach and/or issue a warning at other access points where recreational activities may involve contact with tainted water.

A 2014 report in the Scientific American magazine is among various media sources that explored the possible blue-green algae/ALS connection. That report affirmed that researchers at Dartmouth-Hitchcock Medical Center identified several ALS hot spots in lake and coastal communities in New England, and suspected that toxic blooms of blue-green algae may have played a role.

But the article goes on to state, "While the toxin does seem to kill nerve cells, no research, even in animals, has confirmed the link to ALS."

A more recent 2017 report by University of Maine PhD student Matthew Kruger did connect blue-green algae blooms and BMAA or beta-Methylamino-L-alanine, a non-proteinogenic amino acid, which is associated with an increased prevalence of neurodegenerative diseases including Alzheimer's, Parkinson's, and ALS.

Research on the potential connection continues.