Initial analyses were conducted with 2-d model averaging times, given available activity diaries used in SHEDS-Multimedia; we subsequently focused on 30-d averaging time simulations consistent with the IEUBK period, per recommendations of a work-in-progress peer consultation panel (Versar, Inc.
Using a 2-d model averaging time does not align with IEUBK, but shows closer comparison to NHANES BLL data and GSD, as shown in Supplemental Materials (Figures S2-S3, and Table S6).
The potential effects of Zn on gastrointestinal uptake of Pb are of interest because risk assessment for Pb involves use of the IEUBK
model for lead in children (2,3).
As you know, the IEUBK model is controversial," wrote Bruce Lanphear, MD and Director of the Cincinnati Children's Environmental Health Center, in a May 31, 2004 letter to TCEQ Regional Administrator Richard Greene.
Doctor Ian von Lindern of TerraGraphics Environmental Engineering expressed that EPA may be abusing the uncertainty of IEUBK model results to advance a cleanup level less stringent than 500 parts per million.
The children of Klity villages may be at risk of Pb poisoning by excess Pb exposure via the following five exposure pathways (Figure 2) considered in our IEUBK model: a) directly drinking contaminated water; b) ingesting edible plants grown in Pb contaminated soil, or using Pb contaminated water for irrigation; c) ingesting fish and other aquatic animals; d) being in contact with polluted soil around their houses or playgrounds in the floodplain of the creek; and e) breathing air contaminated by Pb-contaminated dust.
To estimate the probability of the amount of BLLs as a function of Pb in contaminated sediment using IEUBK, we established two relationships: one between Pb in Klity sediment and Pb in drinking water from the creek and one between Pb in Klity sediment and Pb in edible fish in the creek.
In light of uncertainties and limitations of fecal tracer soil ingestion studies, these site-specific estimates likely have broader application to the IEUBK
model and to human health risk assessment.
Short Sheet: Overview of the IEUBK
Model for Lead in Children.
He points to his own unpublished research indicating that less than 5-10% of the lead in urban garden soil is bioavailable, compared with the 30% assumed by the IEUBK
model and ALM, which predict BLLs expected as a consequence of environmental lead exposure.
Mean observed BPb values for recent Indianapolis data are lower than the 1994-1998 results in Syracuse, so IEUBK
model input values would have to be lower to replicate the observations.