You are here:
AN INDOOR PESTICIDE AIR AND SURFACE CONCENTRATION MODEL
Citation:
Furtaw Jr., E J., D. H. Bennett, AND T. E. McKone. AN INDOOR PESTICIDE AIR AND SURFACE CONCENTRATION MODEL. Presented at 12th Conference of the International Society of Exposure Analysis, Vancouver, Canada, August 11-15, 2002.
Impact/Purpose:
Research will be conducted to develop and apply integrated microenvironmental, and physiologically-based pharmacokinetic (PBPK) exposure-dose models and methods (that account for all media, routes, pathways and endpoints). Specific efforts will focus on the following areas:
1) Develop the Exposure Related Dose Estimating Model (ERDEM) System.
Includes: Updating the subsystems and compartments of the ERDEM models with those features needed for modeling chemicals of interest to risk assessors;
Designing and implementing the graphical user interface for added features.
Refining the exposure interface to handle various sources of exposure information;
Providing tools for post processing as well as for uncertainty and variability analyses;
Research on numerical and symbolic mathematical/statistical solution methods and computational algorithms/software for deterministic and stochastic systems analysis.
2) Apply ERDEM and other quantitative models to understand pharmacokinetics (PK) and significantly reduce the uncertainty in the dosimetry of specific compounds of regulatory interest.
Examples of the applications are:
exposure of children to pesticides
study design
route-to-route extrapolation
species extrapolation
experimental data analysis
relationship between parametric uncertainty and the distribution of model results
validity of scaling methods within species
validity of scaling methods from one species to another species
reduction of uncertainty factors for risk assessment
Description:
A thorough assessment of human exposure to environmental chemicals requires consideration of all processes in the sequence from source to dose. For assessment of exposure to pesticides following their use indoors, data and models are needed to estimate pesticide concentrations in air, and loadings (surface concentrations) on a variety of surfaces which humans contact. The objective of the current project is to develop such a model. This model will be used to assist in the assessment of inhalation, dermal, and non-dietary ingestion pathways, which are potentially significant for exposure to pesticides used in residences. A limited amount of data has been collected on pesticide concentrations in various residential compartments following an application. Models are needed to interpret these data and make predictions about other scenarios and other pesticides based on chemical properties. In this presentation, we describe a mass-balance compartmental model with several parameter values derived from fugacity principles. The model simulates pesticide air concentrations and surface loadings following the use of an indoor source, i.e. the application of a pesticide to partial surfaces, such as would occur in a crack-and-crevice application. We include air (both gas phase and aerosols), carpet, smooth flooring, and walls as model compartments. We estimate the compartmental fugacity capacities and mass-transfer rate coefficients for several types of materials commonly found in residences. We also describe the framework and equations for a multi-compartment dynamic mass-balance model, and show model outputs compared to measured pesticide air concentrations and surface loadings as functions of time following a pesticide application.
This is an abstract of a proposed presentation and does not necessarily reflect the United States Environmental Protection Agency (EPA) policy. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.