Kids growing up in Sydney homes are at risk of behavioural problems and IQ loss because of higher levels of lead in household dust, while their parents may face a greater risk of dying early from heart disease.
Preliminary results from DustSafe, a Federal Government-funded study that analyses the contents of vacuum cleaners, reveal homes in Sydney are twice as contaminated by lead as those outside the city.
Average levels of the neurotoxicant were found to be well above the standard maximum in residential soil, which is the nearest comparative measure. One home recorded 30 times the maximum amount.
The warning comes as new US research published in the prestigious medical journal The Lancet reveals low-level lead exposure may be responsible for 30 percent of premature deaths from heart disease.
Principal DustSafe researcher Mark Taylor, professor of environmental sciences at Macquarie University, said the average amount of lead detected in Sydney household dust “is really too high”.
“The concentrations of lead in Sydney homes are about twice what they are in homes outside of Sydney,” Professor Taylor told 9NEWS.
“We know that lead is a particularly damaging neurotoxicant. With respect to young children, it can cause decrements in IQ. We know it has been associated with ADHD and delayed maturation among other things. it impairs development.”
Of his US colleague’s research on the link to heart disease, he added that “there is no reason to assume that Australia has been immune to the consequences of lead exposure as detailed in the new Lancet study.”
“In Australia, we released more than 240,000 tonnes of lead from petrol over its 70 years of use in motor vehicles, causing elevated blood lead levels, particularly in major cities.”
The heart disease research, which involved more than 14,000 people, concluded, “low-level environmental lead exposure is an important but largely overlooked risk factor for cardiovascular disease mortality.”
Whether – or to what extent – children are affected by lead depends on their level of exposure to dust.
Professor Bruce Lanphear, the lead US author of the heart disease research and an expert in childhood exposure to neurotoxins, said kids are most vulnerable in their earliest years when they may get dust on their hands and toys.
“Young children – in particular toddlers, because they put their hands in their mouth so frequently and they are crawling around and grabbing things – most of (their exposure to lead) is through ingestion,” Professor Lanphear said.
“In that first year of life as they are beginning to become more mobile and they still have a lot of mouthing behaviours, that is when we see blood levels (of lead) start to increase.
“And in the second year of life, we start to see other sources like soil or window sill dust because children start to pull themselves up, or they are outside playing and oftentimes will put dirt or soil in their mouth.”
Prevention is key because the damage caused by lead exposure is irreversible, he said.
“As blood levels increase, IQ decreases and as they become school age they start to develop problems with learning and with attention, and ADHD type of problems.”
Lead usually gets into homes from outside, according to Professor Taylor, via soil or dust contaminated by industrial or vehicle emissions. However, renovations can also lead to a spike from old lead-based paint.
“One person’s house that we analysed had 9,000mg per kilogram because they had just renovated the house, pulled down old walls and ceilings,” Professor Taylor said.
Homes in Sydney’s inner-west are more likely to to have high levels of lead in the dust because of legacy contamination.
On the flipside, newer suburbs with modern houses outside the city centre such as Kellyville have lowers levels of lead.
Separate research by Professor Taylor has found children exposed to lead in the past in NSW were more likely to be involved with aggressive crime later in life.
The average amount of lead found in dust from Sydneysiders’ vacuum cleaners was just under 400mg per kilogram – more than the maximum standard limit of 300mg per kilogram in soil in residential gardens.
The preliminary results are based on 100 samples, which Professor Taylor says provide first insights into the prevalence of contaminants in households.
The DustSafe study, which is funded by the Federal Government as a Citizen Science project, is ongoing.