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Susan Griffin,¹ Allan Marcus,² Terry Schulz,³ and Susan Walker⁴

¹U.S. Environmental Protection Agency, Region VIII, Denver, Colorado, USA
²U.S. Environmental Protection Agency, Environmental Criteria and Assessment Office, Research Triangle Park, North Carolina, USA
³Golden, Colorado, USA
⁴AGEISS Environmental, Inc., Denver, Colorado, USA

Abstract

The integrated exposure uptake biokinetic (IEUBK) model, recommended for use by the U.S. Environmental Protection Agency at residential Superfund sites to predict potential risks to children from lead exposure and to establish lead remediation levels, requires an interindividual geometric standard deviation (GSD_i) as an essential input parameter. The GSD_i quantifies the variability of blood lead concentrations for children exposed to similar environmental concentrations of lead. Estimates of potential risks are directly related to the GSDi, and therefore the GSD_i directly impacts the scope of remediation at Superfund sites. Site-specific GSD_i can be calculated for sites where blood lead and environmental lead have been measured. This paper uses data from blood and environmental lead studies conducted at the Bingham Creek and Sandy, Utah, Superfund sites to calculate GSD_i using regression modeling, box modeling, and structural equation modeling. GSD_is were calculated using various methods for treating values below the analytical method detection and quantitation limits. Treatment of nonquantifiable blood lead concentrations affected the GSD_i more than the statistical method used to calculate the GSD_i. For any given treatment, the different statistical methods produced similar GSD_is. Because of the uncertainties associated with data in the blood lead studies, we recommend that a range of GSD_is be used when analyzing site-specific risks associated with exposure to environmental lead instead of a single estimate. Because the different statistical methods produce similar GSD_is, we recommend a simple procedure to calculate site-specific GSD_i from a scientifically sound blood and environmental lead study. Key words: blood lead variability, integrated exposure uptake biokinetic model, interindividual geometric standard deviation, lead exposure, risk analysis. Environ Health Perspect 107:481-487 (1999) . [Online 6 May 1999]

http://ehpnet1.niehs.nih.gov/docs/1999/107p481-487griffin/ abstract.html

Address correspondence to S. Walker, AGEISS Environmental, Inc., 1900 Grant Street, Suite 1130, Denver, CO 80202 USA. Telephone: (303) 861-7558. Fax: (303) 861-7546. E-mail: susanw@ageiss.com

Any views or opinions expressed in this paper are the views of the authors and do not necessarily represent U.S. EPA policy or guidance. No official endorsement should be inferred.

Received 9 March 1998 ; accepted 2 October 1998.