Lead-Contaminated Soil Abatement and Urban Children's Blood Lead Levels
- Michael Weitzman, MD;
- Ann Aschengrau, ScD;
- David Bellinger, PhD;
- Ronald Jones;
- Julie Shea Hamlin, MPH;
- Alexa Beiser, PhD
- From the Department of Pediatrics, University of Rochester (NY) School of Medicine and Dentistry (Dr Weitzman); Department of Epidemiology and Biostatistics, Boston (Mass) University of Public Health (Drs Aschengrau and Beiser); Department of Neurology, Harvard School of Medicine, Boston (Dr Bellinger); Department of Public Health, Cleveland, Ohio (Mr Jones); and Department of Pediatrics, Cedars-Sinai Medical Center, Los Angeles, Calif (Ms Hamlin). Dr Weitzman was a member of the Department of Pediatrics at Boston City Hospital/Boston University School of Medicine during much of this study.
Abstract
Objective. —To test the hypothesis that a reduction of 1000 ppm or more of lead in soil accessible to children would result in a decrease of at least 0.14 μmol/L (3 μg/dL) in blood lead levels.
Setting. —Urban neighborhoods with a high incidence of childhood lead poisoning and high soil lead levels.
Design. —Randomized controlled trial of the effects of lead-contaminated soil abatement on blood lead levels of children followed up for approximately 1 year after the intervention.
Patients. —A total of 152 children less than 4 years of age with venous blood lead levels of 0.34 to 1.16 μmol/L (7 to 24 μg/dL). Children were largely poor and had a mean age at baseline of 32 months, a mean blood lead level of 0.60 μmol/L (12.5 μg/dL), and a median surface soil lead level of 2075 ppm.
Interventions. —Children were randomized to one of three groups: the study group, whose homes received soil and interior dust abatement and loose paint removal; comparison group A, whose homes received interior dust abatement and loose paint removal; and comparison group B, whose homes received only interior loose paint removal.
Main Outcome Measures. —Change in children's blood lead levels from preabatement levels to levels approximately 6 and 11 months after abatement.
Results. —The mean decline in blood lead level between preabatement and 11 months after abatement was 0.12 μmol/L (2.44 μg/dL) in the study group (P=.001), 0.04 μmol/L (0.91 μg/dL) in group A (P=.04), and 0.02 μmol/L (0.52 μg/mL) in group B (P=.31). The mean blood lead level of the study group declined 0.07 μmol/L (1.53 μg/dL) more than that of group A (95% confidence interval [CI], -0.14 to -0.01 μmol/L [-2.87 to -0.19 μg/dL]) and 0.09 μmol/L (1.92 μg/dL) more than group B (95% CI, -0.16 to -0.03 μmol/L [-3.28 to -0.56 μg/dL]). When adjusted for preabatement lead level, the 11-month mean blood lead level was 0.06 μmol/L (1.28 μg/dL) lower in the study group as compared with group A (P=.02) and 0.07 μmol/L (1.49 μg/dL) lower than in group B (P=.01 ). The magnitude of the decline independently associated with soil abatement ranged from 0.04 to 0.08 μmol/L (0.8 to 1.6 μg/dL) when the impact of potential confounders, such as water, dust, and paint lead levels, children's mouthing behaviors, and other characteristics, was controlled for.
Conclusions. —These results demonstrate that lead-contaminated soil contributes to the lead burden of urban children and that abatement of lead-contaminated soil around homes results in a modest decline in blood lead levels. The magnitude of reduction in blood lead level observed, however, suggests that lead-contaminated soil abatement is not likely to be a useful clinical intervention for the majority of urban children in the United States with low-level lead exposure.
(JAMA. 1993;269:1647-1654)
Footnotes
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These findings were reported to the Environmental Protection Agency in July 1992. This article has not been subjected to the agency's peer and administrative review and therefore may not necessarily reflect the views of the agency, and no official endorsement should be inferred.
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Reprint requests to Department of Pediatrics, Rochester General Hospital, 1425 Portland Ave, Rochester, NY 14621 (Dr Weitzman).
