The proof is in the plumbing. Low-level lead contamination of water is widespread in Australian homes, with brass tap fittings the most likely source.

This is the finding of a large-scale study on water samples from kitchen taps in 212 homes dotted across New South Wales, the state that contains Sydney.

Authorities around the world routinely monitor drinking water in storage reservoirs and distribution pipes to ensure that lead levels are below guideline limits. But lead from brass kitchen taps can enter water further down the supply chain, says Paul Harvey at Macquarie University in Sydney.


In their study, Harvey and his colleagues detected lead in 56 per cent of samples – and 8 per cent of those exceeded the limit of 10 micrograms per litre set in the Australian Drinking Water Guidelines.

In a subsequent experiment, the researchers tested water before and after it passed through brass taps, which contain small amounts of lead, and lead-free stainless steel taps. Lead was only found in water that had passed through brass ones.

“Water sits inside the brass barrel of your tap, where it can be exposed to lead for a long time, especially if it sits there overnight,” Harvey says.

Toxic effects

Lead is a neurotoxin that is particularly harmful to children. Studies have linked low-level lead exposure to reductions in IQ and attention span, as well as a greater tendency for antisocial behaviour.

Australia’s 10-microgram lead limit for drinking water was set in the mid-1990s, but the World Health Organization has since deemed that no level of exposure is safe.

The researchers are yet to test whether higher lead levels in home water supplies correlate with higher amounts in the blood and adverse health effects, but Harvey believes there is potential for harm.

“Having seen what I’ve seen in terms of the concentrations in the water and the widespread nature of it, it is raising the alarm,” he says.

A handful of samples contained almost 90 micrograms of lead per litre – comparable to the levels recorded during the recent water crisis in Flint, Michigan, after distribution pipes began to corrode.

However, the Australian results may be unrepresentative because they were collected after taps had been off for 9 hours, says David Simon of the South Australian health department, who sat on the most recent National Health and Medical Research Council lead working committee.

“Generally, people consume water over the whole day,” he says. “Therefore, consumption of contaminants would be lower than indicated by the study, which measured worst-case levels after 9 hours of stagnation.”

Reducing exposure

Evidence of small amounts of lead leaching from taps has also been found in the US and the UK. In 2014, the US government mandated a lead limit of 0.25 per cent in plumbing fittings.

Taps in Australia and the UK are typically made of brass that contains lead at a level of about 2 to 4 per cent.

Introducing similar restrictions to those in the US would be a simple way to cut down on unnecessary exposure levels, even if they are low, says Harvey.

Consumers can also attach lead filters to their taps or switch to stainless steel, he says.

Journal reference: Environmental Research, DOI: 10.1016/j.envres.2016.07.041

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