RAINWATER tanks in Melbourne are commonly contaminated with lead and other heavy metals, a study to be presented this week has found. The joint Melbourne Monash University and CSIRO research found the use of lead in roofs to join surfaces and channel away water elevated the risks, pushing the lead content in tank water as high as 50 times Australia’s drinking water guidelines, The Australian newspaper reports.
But even across a broader range of roof types and tanks, one-third of those surveyed contained lead concentrations in the water exceeding safe drinking levels by up to 35 times.
“Concentrations of aluminium, cadmium, iron and zinc were also found at levels exceeding acceptable health and esthetic levels,” the study reports.
Australians have increasingly embraced rainwater tanks, pushing the share of homes with water tanks to nearly 20 per cent last year from 15 per cent three years earlier.
Of the remainder, 60 per cent of homes are considering installing rainwater tanks, amid escalating water restrictions because of the drought, according to the Australian Bureau of Statistics.
But while most homes with tanks install them to save water, the second most common reason for buying them is to service properties that are not connected to mains water.
In South Australia, almost half of households use some water from tanks, and more than a fifth use them as their main source of drinking water.
Study co-author Grace Mitchell said some people also simply preferred the taste of rainwater, or considered it more natural. “It is more natural in the sense that it’s not treated but in some cases that’s not a good thing,” she said.
The Monash University senior research fellow said the surprisingly large incidence of contamination reinforced the need for people to stick with drinking mains water, or to get their tank water tested for heavy metals.
Footnote: Dr Grace Mitchell is a Senior Research Fellow with the Institute for Sustainable Water Resources in the Dept of Civil Engineering at Monash University. Grace specialises in total urban water cycle management and innovative water servicing approaches for urban greenfield and redevelopment sites.
By Siobhain Ryan THE AUSTRALIAN
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