A Pilot Study of Children’s Blood Lead Levels in Mount Isa, Queensland

Abstract

Mount Isa, Queensland, is one of three Australian cities with significant lead emissions due to nonferrous mining and smelting. Unlike the two other cities with lead mines or smelters, Mount Isa currently has no system of annual, systematic, community-wide blood lead level testing; and testing rates among Indigenous children are low. In previous screenings, this group of children has been shown to have higher average blood lead levels than non-Indigenous children. The first aim of this study was to assess whether parents and children would participate in less invasive, rapid point-of-care capillary testing. The second aim was to measure blood lead levels among a range of children that roughly reflected the percentage of the Indigenous/non-Indigenous population. This pilot study is based on a convenience sample of children between the ages of 12 and 83 months who were recruited to participate by staff at a Children and Family Centre. Over three half-days, 30 children were tested using capillary blood samples and the LeadCare II Point-of-Care testing system. Rapid point-of-care capillary testing was well tolerated by the children. Of 30 children tested, 40% (n = 12) had blood lead levels ≥5 µg/dL and 10% had levels ≥10 µg/dL. The highest blood lead level measured was 17.3 µg/dL. The percentage of children with blood lead levels ≥5 µg/dL was higher among Indigenous children compared to non-Indigenous (64.2% compared to 18.8%) as was the geometric mean level (6.5 (95% CI, 4.7, 9.2) versus 2.4 (95% CI, 1.8, 3.1)), a statistically significant difference. Though based on a small convenience sample, this study identified 12 children (40%) of the sample with blood lead levels ≥5 µg/dL. Due to historical and ongoing heavy metal emissions from mining and smelting in Mount Isa, we recommend a multi-component program of universal blood lead level testing, culturally appropriate follow-up and intervention for children who are identified with blood lead levels ≥5 µg/dL. We further recommend focused outreach and assistance to the Indigenous community, and further control of emissions and remediation of existing environmental lead contamination in children's play and residential areas.

The Blood Lead Levels of Children and the Loss of Ca2+ from Neurons Owing to Lead

“…A downward trend in basic BLLs was observed. The BLLs of boys were higher than that of girls every year, which is consistent with the findings of a previous study [16]. The boy to girl ratio was the highest in 2019, but the median BLL was the second lowest.…”

Trace Element Analysis in Whole Blood and Plasma for Reference Levels in a Selected Queensland Population, Australia

“…The overall mean and reference range values of blood Pb levels (13.6 μg/L; 3.8–49.6 μg/L) in this study were lower than 50 μg/L (5 μg/dL), the recommended threshold for notification and investigation in Queensland population [ 41 ]. Air pollution and emission from mining activities and smelters have been shown to contribute to elevated levels of blood Pb (19–224 μg/L or 1.9–22.4 μg/dL) in Queensland children [ 13 , 42 ]. The blood Pb levels tend to increase and accumulate with age, and the present study has shown that the age group over 40 years had blood Pb levels significantly higher ( p = 0.003) than the age group under 40 years ( Table 7 , Figure S1 ).…”

“…However, there have been studies on levels of individual elements such as lead in children blood in Mt. Isa residents and selenium in selected Queensland populations of different ages [ 13 , 14 , 15 ]. Our work is the first study providing the reference range values of essential and non-essential trace elements in blood and plasma of a selected cohort of adults in Queensland, Australia.…”

Public Health Risks Associated with Heavy Metal and Microbial Contamination of Drinking Water in Australia

“…In Australia, research into child lead levels has been focused on at-risk populations, particularly in the lead mining towns of Mt Isa [37] and Broken Hill, where environmental contamination is thought to be the main driving factor causing elevated BLLs in these communities [38]. A recent small study of 30 children in Mt Isa found that 40% of children had a BLL of ≥5 µg/dL, and 10% had levels of ≥10 µg/dL [39]. In Broken Hill, government intervention in the early 1990s through educational, behavioral, and environmental interventions resulted in a significant increase in the percentage of children with BLLs ≤10 µg/dL, increasing from 13.6% in 1991 to 64.2% in 2001 [40].…”