A new publication contributes additional evidence for the connection between naturally-occurring neurotoxins, produced by cyanobacteria, and neurodegeneration in vulnerable humans (Pablo and others 2009).
Cyanobacteria, sometimes described as blue-green algae, are ubiquitous in freshwater, marine and terrestrial systems, where they produce the neurotoxic amino acid b-N-methylamino-l-alanine (BMAA) as a chemical defense against predators.
Harmful algal blooms, such as those of cyanobacteria, are often attributed to anthropogenic eutrophication--nutrient enrichment of aquatic ecosystems by humans (Smith and Schindler 2009). Phosphorus availability limits algal growth in many lakes, such that additional inputs from fertilizers and detergents can stimulate blooms.
Cyanobacteria, in particular, are able to take advantage of phosphorus inputs as they can fix atmospheric nitrogen, thereby satisfying their metabolic needs and allowing them to out-compete other algal species that do not have a mechanism for fixing nitrogen. These anthropogenic inputs of phosphorus can persist for decades through internal nutrient cycles, posing long-term ramifications for public health.
The Center for Disease Control provides additional information on cyanobacteria, including precautionary recommendations.