Risk Assessment IDentification and Ranking –
Indoor and Consumer Exposure (RAIDAR-ICE) Model
RAIDAR-ICE is a versatile, efficient tool for screening and prioritization of neutral organic chemicals based primarily on near-field direct and indirect exposure pathways and associated potential human health concerns. The model development aims to balance the complexity of processes related to assessing human exposure and potential risk with data availability at a screening-level for thousands of chemicals.
RAIDAR-ICE builds onto the ICECRM mass balance framework. Both models contain an indoor chemical fate module, which describes a generic, evaluative indoor environment consisting of seven compartments (indoor air, polyurethane foam, carpet, vinyl floor, and organic films on vertical, up-facing and down-facing surfaces). In addition, the models include a PBTK model comprising compartments for (i) hand skin surface, (ii) the remaining skin surface on the body, and (iii) the human body. This toxicokinetic model describes the adsorption, metabolism (biotransformation) and elimination (exhalation, renal excretion, fecal egestion, skin desquamation) processes of chemicals and is parameterized here for a representative male adult. Whereas ICECRM considers only human exposure to chemicals released into physical compartments of the simulated indoor environment and subsequent indirect exposures, RAIDAR-ICE additionally includes the capacity for direct chemical applications to the body within the mass balance equations. Far-field exposure estimates (i.e., intake rates from water, food, outdoor air) can be used as input to the RAIDAR-ICE model for aggregate exposure assessment. RAIDAR-ICE also inherits concepts from the RAIDAR model. Most notably, the calculated human exposure is combined with user-defined toxicity (hazard) data to derive risk-based assessment endpoints and critical emission rates.
RAIDAR-ICE is part of the US EPA’s ExpoCast System for the Empirical Evaluation of Models (SEEMS) human exposure framework (https://www.epa.gov/chemical-research/rapid-chemical-exposure-and-dose-research).
– Li, L.; Westgate, J. N.; Hughes, L.; Zhang, X.; Givehchi, B.; Toose, L.; Armitage, J. M.; Wania, F.; Egeghy, P.; Arnot, J. A. 2018. A model for risk-based screening and prioritization of human exposure to chemicals from near-field sources. Environ. Sci. Technol., 52, (24), 14235-14244. DOI: 10.1021/acs.est.8b04059