Manganese in regional water supplies a real concern: CQU researcher
Published:09 March 2021
Many regional Queensland towns battle water discolouration annually and CQU researcher Dr Adam Rose says there are growing concern on the human health effects of Manganese (Mn) in drinking water
As many regional Queensland towns battle water discolouration, there has been growing concern on the human health effects of Manganese (Mn) in drinking water - and bottle-fed babies and pregnant mothers are most at risk.
That’s according to CQUniversity researchers who recently published a paper on the topic.
“If you are pregnant, I would recommend using bottled water, at least until Mn levels have reduced,” CQUniversity water expert Dr Adam Rose explained.
“And if you are currently bottle-feeding your infant, I would recommend using bottled water, as the combination of tap water high in Mn and the additional Mn found in baby formula has the potential to expose the young one to increased levels of Mn.”
Dr Rose explained that recent research had shown that increased levels of Mn in the system contributed to impacts on pregnant women, infant size and mortality, and intellectual function in children as well as in the elderly.
“The primary source of Mn in natural catchments is the surrounding soils, bedrock and organic matter washed into the water bodies that ends up increasing the levels in our regional water supplies.
“Traditionally, Mn has been limited to an aesthetic concern – at about this time every year residents notice their water coming out of taps that is somewhat discoloured and doesn’t look pleasing to drink. We are told is safe to do so – but is it?”
Dr Rose said that while Mn was an essential trace element used in bone formation and in amino acid, lipid and carbohydrate metabolism in humans, too high a level could prove dangerous.
“Chronic exposure to Mn in drinking water at concentrations below the health-based guidelines used in many countries may result in neurological disorders similar to a Parkinson’s-like disease called ‘Manganism’. Along with neurological disorders, modest Mn concentrations in drinking water have also been linked with increased dental caries, behavioural problems, reduced intelligence quotient (IQ) scores, difficulty with mathematics and reduced motor skills in children.”
Dr Rose said the treatment of water containing increased Mn concentrations can be difficult, as Mn took much longer to oxidise and precipitate compared with other metals such as iron.
“Given the challenges of effective and efficient Mn treatment removal, understanding the temporal and spatial relationships of Mn will be invaluable in assisting water managers to refine or customise treatment options. For example, an early forewarning of increased Mn may signal the need to add additional steps in the treatment process, as a measure to effectively remove Mn from the water. This is particularly the case in the context of smaller treatment plants, where resources may be limited, and communities do not have ready access to alternate supplies in the event of water contamination with Mn and resulting discolouration.”
Dr Rose said it remained unclear as to whether or not short-term increases in Mn concentrations could contribute significantly to long-term exposure from drinking water, particularly when age-specific drinking water intake was considered.
He said this problem, and many others, were predicted to become more frequent under climate change scenarios.
“For regional Queensland to ensure safe drinking water supplies into the future we need to start to rehabilitate our regional water cycles,” Dr Rose said.
“The only weapon we have in regional Queensland for our fight against climate change is water. So the solution is simple, we need to slow the flow, and give back our rivers some H2O.”