Review and Analysis of Inhalation Dosimetry Methods for Application to Children’s Risk Assessment
- 1 April 2005
- journal article
- review article
- Published by Taylor & Francis Ltd in Journal of Toxicology and Environmental Health, Part A
- Vol. 68 (8), 573-615
- https://doi.org/10.1080/15287390590921793
Abstract
Young children have a greater ventilation rate per body weight or pulmonary surface area as compared to adults. The implications of this difference for inhalation dosimetry and children’s risk assessment were evaluated in runs of the U.S. Environmental Protection Agency (U.S. EPA) 1994 reference concentration (RfC) methodology and the ICRP 1994 International Commission on Radiological Protection. 1994. Human respiratory tract model for radiological protection., ICRP Pub. No. 66.. [Google Scholar] inhalation dosimetry model. Dosimetry estimates were made for 3-mo-old children and adults for particles and Category 1 and 2 reactive gases in the following respiratory-tract regions: extrathoracic (ET), tracheobronchial (BB), bronchioles (bb), and pulmonary (PU). Systemic dosimetry estimates were made for nonreactive (Category 3) gases. Results suggest similar ET dosimetry for children and adults for all types of inhaled materials. BB dosimetry was also similar across age groups except that the dosimetry of ultrafine particles in this region was twofold greater in 3-mo-old children than in adults. In contrast, the bb region generally showed higher dosimetry of particles and gases in adults than in children. Particle dose in the PU region was two- to fourfold higher in 3-mo-old children, with the greatest child/adult difference occurring for submicron size particles. Particulate dosimetry estimates with the default RfC methodology were below those found with the ICRP model for both adults and children for submicrometer sized particles. There were no cases in which reactive gas dosimetry was substantially greater in the respiratory regions of 3-mo-old children. Estimates of systemic dose of Category 3 gases were greater in 3-mo-old children than in adults, especially for liver dose of metabolite for rapidly metabolized gases. These analyses support the approach of assuming twofold greater inhalation dose in children than adults, although there are cases in which this differential can be greater and others where it can be less.Keywords
This publication has 86 references indexed in Scilit:
- Ontogeny of Hepatic and Renal Systemic Clearance Pathways in InfantsClinical Pharmacokinetics, 2002
- DOSIMETRY MODELING OF HIGHLY SOLUBLE REACTIVE GASES IN THE RESPIRATORY TRACTInhalation Toxicology, 2001
- A CFD–PBPK Hybrid Model for Simulating Gas and Vapor Uptake in the Rat NoseToxicology and Applied Pharmacology, 1998
- Onset of xenobiotic metabolism in children: Toxicological implicationsFood Additives & Contaminants, 1998
- Size, Myths and the Clinical Pharmacokinetics of Analgesia in Paediatric PatientsClinical Pharmacokinetics, 1997
- Seasonal and spatial variation of the bacterial mutagenicity of fine organic aerosol in southern california.Environmental Health Perspectives, 1996
- Experimental data for total deposition in the respiratory tract of childrenToxicology Letters, 1994
- An Analysis of Pollutant Gas Transport and Absorption in Pulmonary AirwaysJournal of Biomechanical Engineering, 1990
- A model of the regional uptake of gaseous pollutants in the lung *1II. The sensitivity of ozone uptake in laboratory animal lungs to anatomical and ventilatory parametersToxicology and Applied Pharmacology, 1987
- Oral breathing in newborn infantsThe Journal of Pediatrics, 1985