Toxic Truth: Lead found unsafe at any level in body

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A DECADE after Pasminco’s lead and zinc smelter closed at Boolaroo and as the land is being prepared for redevelopment, the Newcastle Herald and Macquarie University collected more than 130 soil and  dust samples from homes and public spaces in surrounding suburbs. The analysis revealed alarming levels of contamination remained, despite a government-approved Lead Abatement Scheme.

AUSTRALIAN blood lead level guidelines are expected to be halved next year, after a national report found there was no safe level of exposure.

The recommended standard of lead in blood is likely to fall from 10 micrograms per decilitre to under five, with any readings above the proposed new level to be reported to public health authorities.

A National Health and Medical Research Council  draft report, issued earlier this year, found that even low lead exposure was associated with behavioural problems such as poor attention, impulsivity and hyperactivity.

In adolescent boys and girls it was linked to a delay in physical sexual maturity and in adults, including pregnant women, with increased blood pressure.

Most critically, the report found children’s exposure to very small amounts of lead – resulting in blood lead levels below five – was associated with reduced average academic achievement and IQ.

Chair of the NHMRC Lead Working Committee, Adjunct Associate Professor Sophie Dwyer, said the paper’s findings – based on a review of scientific evidence from OECD countries between 2004 and 2013 – were ‘‘not surprising’’.

‘‘One of the problems with lead is it has no role in the body, it doesn’t contribute to the body’s functioning,’’ she said.

In the past, Australian authorities attempted to identify how much lead people could ‘‘safely’’ be exposed to without risking their health, but the conversation has since changed.

 Pasminco Sulphide at Cockle Creek

Pasminco Sulphide at Cockle Creek

‘‘There is no ‘safe’ level of lead that has been proven not to cause any health problems,’’ the report states.

Dr Dwyer estimates the current average blood-lead level among Australians would be around two.

This level is much lower than for previous generations, when lead was used in many industries and products and added to paints and petrol.

‘‘We looked at what the current background levels were and set five as a level above which you are probably seeing an exposure that’s not background exposure,’’ Dr Dwyer said.

‘‘It’s not a safe level, but a level that indicates a person is exposed to lead in an atypical way.’’

While low exposure to lead indicated by levels of less than 10 does not cause noticeable health effects, it may have subtle health effects  detected when comparing large groups of people such as communities or regions.

The World Health Organisation updated its fact sheet on lead in October, which said childhood exposure was linked to about 600,000 new cases of children developing intellectual disabilities every year.

‘‘There is no known safe blood lead concentration,’’ the fact sheet reiterated.

‘‘But it is known that, as lead exposure increases, the range and severity of symptoms and effects also increases.’’

The NHMRC committee’s final report will be referred to the council when it meets in March.

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