Evaluation of home lead remediation in an Australian mining community
Introduction
Protecting children from the consequences of previous widespread use of lead is an ongoing challenge. While primary prevention is clearly important to avoid more children being exposed to lead, effective strategies for reducing already elevated blood lead levels are also required.
A recent Cochrane review of 12 randomized controlled trials of household interventions in communities where paint was the major source of lead exposure concluded that education and dust control on their own were not effective in reducing blood lead levels of young children (Yeoh et al., 2008). More intensive interventions to remove or control sources of lead in a child's home environment (i.e., home remediation or abatement) have ‘common-sense’ appeal but can be logistically complex and costly to implement, and their effectiveness is not well established (Haynes et al., 2002.) Various strategies, including remediation or abatement of homes, appear to have contributed to declines in blood lead at hazardous waste sites (Lorenzana et al., 2003), but overall the effectiveness of soil abatement and combinations of interventions remain unclear due to a lack of evidence (Yeoh et al., 2008). Thus, despite the difficulty of implementation in a way that is consistent with necessary public health responses, there is clearly a need for better quality evidence about the effectiveness of lead remediation programs, and stringent epidemiological evaluations are required (Lorenzana et al., 2003). This paper reports the results from a randomized controlled trial of home remediation that was integrated into a lead management program which aimed to reduce blood lead levels of pre-school aged children in Broken Hill, a mining town in the arid region of New South Wales, Australia.
Lead has been mined in Broken Hill for over a century and was considered as primarily an occupational health and safety issue. A combination of factors, including local concern over dust generated from an open cut mine in the center of town and increasing evidence of the health effects of blood lead levels previously thought safe, resulted in the blood lead levels of the city's children being surveyed in 1991; 86% had blood lead levels of 10 µg/dL or above (Lyle et al., 2006). Initial investigations showed soil and dust to be major lead sources for both children and indoor dust; paint and petrol were also important sources (Gulson et al., 1994, Phillips, 1998). In 1994 a government-funded program (described in detail in Lyle et al., 2006) was established to reduce blood lead levels among pre-school aged children. It included five elements:
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blood lead monitoring and case finding targeting all pre-school aged children;
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case management of children with high blood lead levels;
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public land remediation;
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public education and health promotion; and
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evaluation, research and development.
Case management options for children with high blood lead levels were based on the then Australian National Health and Medical Research Council Guidelines (National Health and Medical Research Council, 1993) and informed by local data and studies that established a link between high blood lead levels in Broken Hill children and lead levels in garden soils and house dust and hand mouth behaviour (Phillips, 1998). The use of remediation/abatement of residential dwellings as a case management option was also supported by findings that poorly sealed ceilings and walls in Broken Hill homes were an important potential source of lead in household dust (Boreland et al., 2002) and that paint was a significant lead source for some children (Gulson et al., 1994).
Thus, home remediation was included as a part of the case management program for children with blood lead levels ≥ 15 µg/dL from 1995. Eligible children with blood lead levels ≥ 30 µg/dL were offered immediate home remediation. Eligible children with blood lead levels of 15–29 µg/dL were allocated to ‘immediate’ or ‘delayed’ home remediation; a subset of these participated in a randomized controlled trial.
This paper addresses two questions:
Does home remediation lower blood lead levels in young children who have blood lead concentrations between 15 and 29 µg/dL?
Are changes in children's blood lead level correlated with changes in indoor lead loading after remediation— i.e., is there a dose response effect?
Section snippets
Case management program
A blood lead surveillance program, in place since 1990, aims to test all pre-school aged children annually. The parents of all children tested receive information and education about lead hazards. An algorithm for the management of children with elevated blood lead has been developed (Lyle et al., 2006) and modified. If a child's blood lead level was ≥ 15 µg/dL, their home was assessed for lead, environmental samples were collected, and their behaviour assessed.
Blood lead testing and quality assurance
Trained venepuncturists collected 1
Results
Of the 1231 children screened between October 1994 and August 1996, 365 (29.7%) were eligible for home lead remediation. The families of 117 agreed to the conditions and were enrolled into the program (Fig. 1). Four did not return for blood lead testing after remediation and so have been excluded from all analysis. The characteristics of the remaining 113 children are shown in Table 2. Thirteen of these had an initial blood lead level ≥ 30 µg/dL and so were not enrolled in the randomised trial,
Discussion
The Broken Hill community has benefited over two decades from a successful environmental lead management program that has seen a steady and sustained decline in blood lead levels in young children (Lyle et al., 2006, Boreland et al., 2008). Home lead remediation was a major feature of the management program between 1995 and 1997, and was provided to around one-in-ten children tested. While the removal or containment of all sources of lead in a home and yard would be expected to effect a
Acknowledgements
Bill Balding, Stephen Corbett, and Hugh Burke developed the Broken Hill Lead Management Program and the initial study design, and Geoffrey Morgan provided early statistical support. The continued decline in the blood lead level of children in Broken Hill is testament to the dedication and effectiveness of the staff of the Broken Hill Lead Management Program. The Broken Hill University Department of Rural Health is funded by the Australian Government Department of Health and Ageing.
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