Use of the IEUBK Model for Determination of Exposure Routes in View of Site Remediation

ABSTRACT

The Integrated Exposure Uptake Biokinetic (IEUBK) model is frequently used to estimate blood lead concentrations of children exposed to lead. Simulations with the IEUBK model were run to estimate the blood lead concentration in children living in the vicinity of a non-ferrous plant, situated in Hoboken, Belgium. Concentrations in soil ranged from 59–2425 mg Pb/kg dm, average concentrations in house dust ranged from 234–73394 mg Pb/kg dm. Measured blood lead concentrations in children aged 2–7 years were between 3 and 35 μ g/dl. Exposure sources were indoor dust in the house and the school, outdoor dust and soil in the home surrounding and at the school's playground, and suspended dust in the air. Soil ingestion values and lead exposure from food were changed to Flemish values. The model was able to predict the measured blood lead concentrations adequately except for the lowest exposure group. Predictions showed a systematic overestimation. Analysis of the data revealed that the neighbourhood's school is an important source of exposure to lead; indoor house dust dominates exposure for children going to school outside the area, because of the high concentrations of lead in indoor dust (3 to 5 times higher than in outdoor soil).

Key Words:

• IEUBK
• exposure assessment
• lead
• children

ACKNOWLEDGMENTS

This study was made possible by the financial support of Umicore nv. The study was reviewed by the Medical Working Group for the Moretusburg quarter.

Notes

¹: Averagesoilconcentrations (C _soil ) were calculated as

where time spent outside (t_outside) equals 2.88 h/d for the home, 0.7 h/d for the school and 0.42 h/d for places outside the Moretusburg quarter respectively; average dust concentrations (C_dust) were calculated as

where time spent inside (t_inside) equals 4.37 h/d for the home (excluding sleeping), 2.8/d for the school and 0.83 h/d for places outside the quarter, respectively (excluding sleeping).

²: Zone represents location of the house; school represents location of the school: inside quarter (school Mo) or outside quarter (school outside Mo).