Algal blooms harm the environment by releasing toxins

The emerging toxin β-methylamino-L-alanine (BMAA) and its toxic structural isomer 2,4 – diaminobutyric acid (2,4-DAB) were detected in algal samples collected from both rural and urban waterways. These neurotoxins, produced by cyanobacteria that are a feature of algal blooms in Australian rivers and lakes, have been the subject of a number of recent studies linking them to neurodegenerative disease patient clusters.

These toxins are associated with amyotrophic lateral sclerosis (ALS) or motor neurone disease (MND). MND is also known as Lou Gehrig’s disease in the US.

The UTS led research, aimed at establishing standard methods to detect and quantify these toxins, highlights the need for the development of a robust monitoring program for Australian cyanobacterial blooms, the researchers say.

Waterways in the Murray –Darling basin in eastern Australia are of particular concern because the semi-arid environment, use of river water for irrigation, slow moving water and high risk of eutrophication make these rivers susceptible to frequent large scale blooms.

“Cyanobacteria are an ancient group of microorganisms found in both terrestrial and aquatic environments and they produce a diverse range of bioactive molecules some of which are toxic to humans and animals,” says UTS researcher and Chief Investigator on the study, Associate Professor Kenneth Rodgers.

“There is very strong evidence now that these toxins are associated with the formation in the brain of protein aggregates similar to what we see in Alzheimer’s disease and ALS amyotrophic lateral sclerosis or motor neurone disease, patients,” Dr Rodgers says.

The researchers say that BMAA is of particular concern because it is fairly ubiquitous and accumulates through the food chain which increases the risk of human exposure through diet.

“BMAA is also thought to be capable of spreading via aerosols and a recent North American epidemiological study confirms that people who live near water bodies that experience frequent cyanobacterial blooms have an increase ALS risk,” UTS Faculty of Science PhD candidate and lead author of the study Brendan Main says.

The relationship between BMAA and neurodegeneration is also supported by a number of recent laboratory and field studies. The fact that BMAA was frequently detected in the local bloom samples suggests the toxin may be common in the aquatic environment and strengthens the argument for ongoing monitoring of both BMAA and 2,4-DAB in drinking water and water used for primary production, the researchers say.

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