North Lake Macquarie - Blood Lead testing 2015

Background

A lead smelter operated in Boolaroo between 1897 and 2003. Studies from 1991 onwards found elevated blood lead levels in children who lived within several kilometres of the smelter. In 1991, 84% of children aged one to four years in Boolaroo and Argenton had blood lead levels of 10 micrograms per decilitre (µg/dL) or above, a level at which learning and behavioural problems may occur.

From 1998 to 2001 a household abatement program provided carpet and ceiling vacuuming, removal of visible slag and top dressing of soil. There was however no appreciable reduction in children’s blood lead levels as a result. 

After the smelter’s closure, average blood lead levels in children under five years of age steadily declined from 9.6 µg/dL in 2003/04 to 6.8 µg/dL in 2004/05 and to 4.5 µg/dL in 2005/06. The proportion of children in this age group with lead levels greater than 10 µg/dL also declined from 40% in 1997 to 26% in 2004, 17% in 2005 and 7% in 2006.

National Health Medical Research Council

Australia’s National Health and Medical Research Council’s (NHMRC) recent review of lead exposure confirmed there is convincing evidence for adverse health impacts if a person has a blood lead level of 10 µg/dL or greater.

Young children are more likely to be exposed to lead, to absorb it and accumulate it during their important developing years. The NHMRC recognises that most Australians live in areas where there are small amounts of lead. It recommends that a blood lead level greater than 5 µg/dL may indicate avoidable exposure to lead and should be investigated and reduced, particularly for young children and pregnant women. For further information, see the NHMRC information paper.

Blood lead screening program in North Lake Macquarie 2015

In 2014 Macquarie University students analysed soil samples in North Lake Macquarie and found that half of them had lead levels greater than the Health Investigation Level of 300 parts per million (ppm).  This was not unexpected as no significant remediation had occurred in the area.

There is a known link between lead-in-air levels (in this case, emissions from the functioning smelter) and blood lead levels. While previous lead screening indicated that reduction of lead-in-air levels rather than soil levels were responsible for reductions in blood lead levels in children in North Lake Macquarie, it was important to confirm the previous downward trend had continued and respond to community concerns.

Between 29 June and 17 July 2015, HNE Health screened 72 children aged from six months to five years of age and eight pregnant women living in Boolaroo, Argenton and Speers Point. The screening involved a single finger prick which was considered less distressing for young children, and families were given the results immediately.

In this most recent screening program, no one returned a blood lead level greater than 5 µg/dL. The machine used for testing can detect blood lead levels as low as 3.3 µg/dL. Levels below this display on the machine as ‘low’ and of the 72 children tested, 63 (88%) returned a ‘low’ reading.

The methods and results of the blood lead survey in North Lake Macquarie have been carefully considered by the expert Lead Reference Group (LRG) advising the NSW Chief Health Officer.  The LRG concluded that results indicate that the risk of children accumulating excess lead in the area has remained low since the closure of the smelter in 2003. The group included Professor Alison Jones a globally recognised clinical toxicologist.  Professor Jones advised, “The low blood lead levels in the children and pregnant women screened are reassuring, and confirm the steady decline in blood lead levels since the Pasminco lead smelter was closed in 2003”.

For more information, see the Blood Lead Screening in North Lake Macquarie, 2015 final report.

In line with the NHMRC Position Statement on Lead and the screening protocols endorsed by the LRG, clinical follow up is not required for any of the children or pregnant women who participated in the screening.

In addition to lead exposure related to previous smelting, parents and pregnant women should be aware of other potential sources of lead including old paint (prior to 1970), which may pose a risk particularly during home renovations.

Blood Lead Testing 

For those who did not participate in the Blood Lead Screen in 2015, screening of children aged six months to five years of age and pregnant women from Boolaroo, Argenton and Speers Point is available and can be organised through consultation your family doctor, using a traditional venous blood test.