At first sight, Griffith seems like a regular rural town in the Murrumbidgee Irrigation Area of Australia. In recent years, however, a potential link has been discovered between a fatal disease and a lake in this town, namely between Motor Neuron Disease (MND) and Lake Wyangan.
MND is a progressive neurological disorder that slowly takes away people’s ability to walk, speak, swallow and finally breathe. According to Health Direct, people diagnosed with MND usually live another 2-3 years. MND is caused by a genetic condition or a combination of environmental, lifestyle and genetic factors. The number of non-genetic cases in Australia has increased by 250% in the last 25 years, but the situation is worst in New South Wales’s agricultural area, Riverina, which includes the towns of Griffith and Wagga Wagga, where rates of MND are 7 times the national average (The Guardian) .
What might be causing these abnormally high numbers? Scientists blame the blue-green algae in Lake Wyangan, which is close to Griffith and surrounded by farms. It is a terminal, dual-basin lake that receives inflows from natural drainage, irrigation return flows, local stormwater and, supplementary “top ups” that arrive via irrigation infrastructure.
SBS News and Griffith City Council claim that blue-green algae results from a combination of drought, calm weather conditions and irrigation return flows. These algal blooms affect aquatic life, block water pumps and can make water undrinkable.
NB: “Blue-green algae” is a misleading name, since it refers to a cyanobacterium that produces a neurotoxin called BMAA. The fact that algal toxins can be colourless and odourless as well as persisting for weeks after an algal bloom makes it hard to avoid BMAA.
A study published in 2020 found that the ingestion of BMAA causes nerve damage similar to that observed in the early stages of MND. Although there is not yet enough evidence to prove blue-green algae causes MND, the connection deserves attention. According to The Guardian, the NSW government does not want to fund research, since a causal link could lead to legal liabilities for the government.
Despite all these challenges, the Griffith City Council has ambitious plans to improve water quality in the lake and sustainably supply water to Riverina’s irrigators. The plans focus on reducing salinity and managing nutrient levels to reduce algal blooms as well as connecting the two basins so that a flow-through system improves irrigation water quality.
The future will determine if those plans are effective.
* Please help my Water Scarcity students by commenting on unclear analysis, alternative perspectives, better data sources, or maybe just saying something nice 🙂