BMAA is a toxin that has been linked to several neurodegenerative diseases such as ALS, Parkinson’s, and Alzheimer’s. Although the neurotoxin is not fully understood, its correlation with degenerative loco-motor symptoms is enough to cause alarm for scientists, especially now after a new study from University of British Columbia's Okanagan campus has discovered high levels of BMAA in cyanobacteria blooms in Lake Winnipeg.
Cyanobacterial blooms have been present in Lake Winnipeg since the mid-1990s because of more and more phosphorus in the lake from fertilizers. These blooms have become more extreme as climate change and eutrophication also take their toll.
"Cyanobacteria blooms have become increasingly common in Lake Winnipeg since the 1990s," says Susan Murch, the lead author of the study. "These bacteria have also been known to produce BMAA under the right conditions and we wanted to establish whether this could be happening in one of Canada's largest and most important freshwater lakes." The research is published in the journal, Neurotoxicity Research.
"Agricultural and human activities along with factors like climate change are very likely behind the increased size and frequency of blooms," Murch says. "We now know that with these blooms comes the very real risk of increased exposure to BMAA and the public health impacts that follow."
Partnering with the Lake Winnipeg Research Consortium, the researchers collected samples of cyanobacteria from sampling stations and blooms in the lake throughout July and September in 2016. They later analyzed the samples for BMAA and found high levels of the neurotoxin in the center of the north basin of the lake, the deepest and lowest-nitrogen zone of the lake where the bloom is the most extreme. BMAA levels here were measured at an average concentration of 4 μg/g. “These findings indicate that the production of non-protein amino acids varies with the depth and nutrient contents of the bloom,” write the authors.
Much more research needs to be conducted in order to understand if BMAA bioaccumulation threatens the entire Lake Winnipeg food web (and hence the people eating the fish). The authors also warn that these blooms are common in freshwater lakes worldwide, and it’s possible that other lakes also have high concentrations of BMAA.
"We hope that an increased awareness of risks of BMAA along with a better understanding of the human impacts on algal blooms will help us better manage the potential consequences to public health."