Researchers believe that similar issues in domestic kitchen taps are likely across Australia.

A new study indicates that some Australians could be getting a dangerous level of lead contamination from their kitchen taps.

Researchers from Macquarie University have detected copper and lead contaminants in domestic water samples across New South Wales - and in some cases the levels exceed what’s listed as acceptable in the Australian Drinking Water Guidelines set by the National Health and Medical Research Council.

Back in 2014, the researchers enlisted volunteer help from the community to gather domestic water samples. The results were published this week in Environmental Research.

Problem lies with taps, not water supply

“The water supply is fine. The issue is the water in the house,” says study co-author Professor Mark Taylor.

“We were aware that domestic water may be accidentally contaminated through lead use in brass fittings, so to characterise that we wanted to know what the extent of in-house contamination was.”

The water samples were collected after water sat in a tap for a nine-hour ‘stagnation period’, similar to what happens when you run the tap first thing in the morning to fill the kettle.

"My results show that there is quite a significant concentration of lead and copper in the drinking water that is coming out of people's kitchen taps into their morning cup of tea, or baby formula," says lead author of the study, PhD researcher Paul Harvey.

The team tested 212 such ‘first draw’ samples, and found copper in nearly all of them, while lead was present in 56 per cent of the households tested. According to guidelines, drinking water should contain no more than 10 micrograms of lead per litre - but 8% of the lead samples contained higher levels that that.

"The highest concentration sample that I collected in this study was 89 micrograms [of lead] per litre," says Harvey. “The results of this study demonstrate that along with other potential sources of contamination in households, plumbing products that contain up to 2.84 per cent of detectable lead are contributing to contamination of household drinking water.”

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A potentially widespread problem

The researchers believe their results could be extrapolated to the population of the whole country - making it a considerable health concern.

“Eight per cent may not sound like a big number, but if it is eight per cent of the Australian population, we're talking about a lot of people,” says Harvey.

“The sampling method appears robust and is analogous to that used in the United States,” says Professor Marc Edwards from Virginia Tech in the US, a leading water quality expert who was not involved in this study.

“While at one level collecting about 200 samples and finding 8% above Australian guidelines would appear to be a stretch in identifying a problem as widespread, in this case it merely confirms the obvious - Australian plumbing systems are subject to the exact same problems found elsewhere in the world,” he adds. Hot coffee causes cancer? Here's what you really need to know What's the actual deal with cancer, hot drinks, and coffee?

Health concerns from lead

Lead is well known for its harmful effects on the human body, and according to the NHMRC, infants, children, and pregnant women are at the greatest risk. Drinking water with high levels of lead can lead to its accumulation in the body, posing particular risks to children’s brain development even when there are no obvious signs of poisoning. Copper contamination is a less severe problem, but prolonged exposure can lead to liver damage.

“Something should be done to make consumers aware of the problem and avoid irreversible health harm,” states Edwards, who was involved in uncovering the high levels of lead contamination in the water supply of Flint, Michigan.

"The idea is not to set fear in everybody's minds and to tell them to stop drinking water. We want people to be vigilant and be aware that these things can be in the water," Harvey explains.

In response to this study, a NSW Health spokesperson tells SBS Science that “copper and lead dissolving from plumbing fixtures into drinking water has been recognised for a long time and is addressed in fact sheets for these compounds in the Australian Drinking Water Guideline.”

According to NSW Health drinking water recommendations, if water is left standing in the pipes for an extended time, it’s advisable to flush it from your tap for 2-3 minutes, and use that water for non-food related purposes, such as watering your plants.

“Despite following this established protocol, some of the flushed water samples still contained considerable concentrations of both copper and lead,” the researchers write.

Collecting water in rainwater tanks poses a higher risk of contamination, so NSW Health advises consumers to manage their tanks properly to avoid these risks.

It can be difficult to discern whether the plumbing in your house might be contaminating your water, so researchers are advising consumers to be cautious - especially if the family has young children.

“To mitigate the risks, perhaps you might buy a filter that is efficient at removing heavy metals, for example," suggests Harvey.

They are also advising worried consumers to get in touch with their water supplier or the local council to see whether water testing at the household level is available. If lead is confirmed to be a problem, changing taps to lead-free ones could be a necessary step - however, that incurs a higher cost.