Estimating the effects of soil remediation on children’s blood lead near a former lead smelter in Omaha Nebraska, U.S.

Background: Lead exposures from legacy sources threaten children’s health. Soil in Omaha Nebraska was contaminated by emissions from a lead smelter and refinery. The U.S. Environmental Protection Agency removed and replaced contaminated soil at the Omaha Lead Superfund Site between 1999 and 2016. Objectives: We assessed the association of blood lead levels (BLLs) in children living near or on the site with both soil lead concentrations and soil remediation. Methods: We linked information on soil lead concentrations at residential properties with children’s BLLs, grouping children based on whether they had pre- and/or post-remediation BLLs. We examined the association of soil lead concentrations with elevated BLL using generalized estimating equations (GEEs). We estimated the odds ratio (OR) of pre-remediation to post-remediation elevated BLL using GEE and conditional logistic regression. We applied a difference-in-differences approach to examine improvement in BLL, comparing pairs of consecutive BLLs with and without soil-based intervention. All analyses controlled for temporal trends and children’s characteristics. Results: Elevated BLL (>5 µg/dL) was associated with both residential (e.g., OR=1.94 [95%CI: 1.77, 2.13; 400-800 versus 5 or 10 µg/dL) was higher before remediation (ORs ranged from 1.48 to 6.61) in models that examined this relationship across and within children. BLL reduction was not associated with soil-based intervention in fully adjusted difference-in-differences models. Conclusion: Both residential and neighborhood soil concentrations were important predictors of elevated BLL in children residing near or on this superfund site. Neighborhood soil remained a strong predictor following remediation. We showed the benefit of soil remediation in most models. Difference-in-differences results should be interpreted cautiously for reasons including the high correlation between remediation and time between BLLs.

Impact/Purpose

This research improved our understanding of factors that contributed to the reduction of blood lead levels (BLLs) at the Omaha Lead Superfund Site (OLSS). We showed an association of soil lead concentration and EPA soil removal and replacement actions with reductions in BLLs of children living near a former lead smelter. Lessons learned from compiling and analyzing these data can help inform and guide efforts of others who are conducting analyses at similarly affected sites.

Citation

Ye, D., James Brown, D. Umbach, J. Adams, W. Thayer, M. Follansbee, AND E. Kirrane. Estimating the effects of soil remediation on children’s blood lead near a former lead smelter in Omaha Nebraska, U.S. National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, NC, 130(3):037008 1-17, (2022). [DOI: 10.1289/EHP8657]

• EHP8657.S001.ACCO.PDF (PDF)  (NA  pp, 1.2 MB, about PDF)
• EHP8657.PDF (PDF)  (NA  pp, 1.5 MB, about PDF)
• EHP8657.SMCONTENTS.508.PDF (PDF)  (NA  pp, 324.0 KB, about PDF)

DOI: Estimating the effects of soil remediation on children’s blood lead near a former lead smelter in Omaha Nebraska, U.S.