Menindee resident John Brereton has a theory about what caused his wife, Pam, to develop motor neurone disease (MND), and it is a path that scientists are investigating.
Up to 2,000 Australians are estimated to have MND, but diagnosis is painstakingly difficult because researchers are not yet sure how the disease is triggered.
"I couldn't really say for certain, but I do believe the blue-green algae has got something to do with it," Mr Brereton said.
Ms Brereton grew up in Ballarat, near Lake Wendouree, which experiences algal blooms like many waterways in Australia.
John and Pam Brereton also lived in the Darling River town of Menindee for 19 years and used river water for cleaning and bathing, but drank filtered rainwater.
Menindee, in far-west NSW, was the scene of mass fish kills over summer, which the Department of Primary Industries said were caused partly due to blue-green algae.
"The algae has killed the fish. It's killing everything, actually," Mr Brereton said.
Fears in Menindee reflect those of people in Griffith in central NSW, where the incidence of MND is seven times higher than the national average, according to recent research.
The common link between the towns is proximity to a water source that is frequently beset by outbreaks of blue-green algae.
However, the CEO of the Motor Neurone Disease Association of NSW (MND NSW) Graham Opie is not convinced.
"There are so many theories. The fact is we just don't know what causes or triggers MND," he said.
Blue-green algae, or cyanobacteria, are the oldest living organisms on the planet precisely because they are good at out-competing others by releasing toxins.
One of these is the neurotoxin BMAA.
Dr Ken Rodgers from the Neurotoxin Research Group at the University of Technology Sydney specialises in environmental neurotoxins and how they interfere with the body's functions.
"I think people should be worried. I get contacted regularly by people who have MND and have had obvious exposure to cyanobacteria," Dr Rodgers said.
Cyanobacteria are always present in rivers and lakes, but only bloom into blue-green algae when conditions are favourable.
Low water flows, high temperatures, and nutrient build-up from agricultural run-off are all factors that contribute to algal blooms.
"I'm not trying to be alarmist," Dr Rodgers said.
"Algal blooms are dangerous, but they're being monitored by professionals so just follow the guidelines."
Alerts issued by water authorities stipulate that people should not swim in, drink from, or eat seafood from algae-affected waterways.
Dr Rodgers said governments should be doing more than that to mitigate risk.
"You've got to try to take away the risk, even if it's not going to affect everybody," he said.
"Governments have got to start looking after the waterways, keep flows going, stop allowing big companies to dump chemicals into the waterways."
Mr Opie of MND NSW said there had been no recorded increase in its membership base in the far-west of NSW, an area struck by repeated blue-green algae events in its waterways.
"We've had fairly constant numbers, and those numbers haven't changed in the 13 years I've been with the organisation," he said.
Dr Rodgers said that just because toxins may be present in the water, it did not mean people exposed to blue-green algae would get sick.
"Someone who smokes from 16 to when they're 100 years old doesn't disprove that smoking causes cancer, it just shows that some people have resistance genes, and some have susceptibility genes," he said.
"It's the same story with exposure to environmental toxins."
But he believed "there's no question that BMAA can cause neurological disease".
"The question is — how big is the risk and what makes you susceptible?" Dr Rodgers said.
He is calling on governments to invest more research dollars into the environmental factors that may trigger MND.
"What we're trying to do is understand how the toxin affects us, and from there we could try to work out what the susceptibility genes might be," he said.
Mr Brereton of Menindee said he believed he would never know exactly why his wife got sick, but hoped that some day the cause would become clear.
"She was a fit woman all her life, worked, never had any illnesses, and then all of a sudden — bang," he said.
"I just hope that no-one has to put up with it. It's a very cruel disease."
Posted Wed 27 Mar 2019 at 7:45pm Wednesday 27 Mar 2019 at 7:45pm Wed 27 Mar 2019 at 7:45pm , updated Wed 27 Mar 2019 at 8:25pm Wednesday 27 Mar 2019 at 8:25pm Wed 27 Mar 2019 at 8:25pm
