Lead (Pb) is a toxic heavy metal with no known biological role in the human body. Blood lead testing measures the concentration of lead in whole blood, which reflects recent and ongoing exposure. Lead is a potent neurotoxin, particularly damaging to the developing nervous system of children, but also harmful to adults at elevated concentrations.
Lead accumulates in bone over years, creating a long-term reservoir that can release lead back into circulation during pregnancy, breastfeeding, menopause, and periods of bone resorption. Even low blood lead levels previously considered safe are now associated with cognitive decline, hypertension, and reduced kidney function in adults. There is no established safe blood lead level.
FAQs
Where is lead exposure most common in Australia?
Lead exposure remains a concern in workers in battery manufacturing, smelting, foundry work, lead plumbing, and some mining and recycling industries. Environmental exposure from lead paint in pre-1970s homes (particularly during renovation), contaminated garden soil near highways or industrial sites, and some imported products also contributes.
Can lead accumulated in bones be released later in life?
Yes. The skeleton stores approximately 90% of total body lead. During periods of increased bone turnover including pregnancy, breastfeeding, menopause, and osteoporosis, stored lead is released back into the blood. This is why women may have elevated blood lead in pregnancy or post-menopause even without current exposure.
Is there a safe blood lead level?
No safe threshold has been established. Even levels below 0.24 umol/L are associated with some degree of neurocognitive effects, particularly in children. The goal is to minimise exposure as much as possible rather than stay below a specific threshold.
What are the symptoms of lead poisoning?
Acute high-level lead poisoning causes abdominal pain, vomiting, encephalopathy, and seizures. Chronic lower-level exposure causes more subtle effects including fatigue, irritability, difficulty concentrating, headache, peripheral neuropathy, and hypertension. Many people have no obvious symptoms despite elevated blood lead.
