Human exposure to cyanobacteria and BMAA.

Cyanobacteria are found worldwide, primarily in aquatic habitats. They are increasing in abundance as a result of increasing nutrient inputs from various human activities. Recent data indicate that most cyanobacteria produce the neurotoxin beta-N-methylamino-L-alanine (BMAA), and this toxin can biomagnify UP some food chains to rather high concentrations in animals used as food by humans. BMAA may pose an increasing human health risk.