A probabilistic modeling approach to assess human inhalation exposure risks to airborne aflatoxin B1 (AFB1)

To assess how the human lung exposure to airborne aflatoxin B1 (AFB1) during on-farm activities including swine feeding, storage bin cleaning, corn harvest, and grain elevator loading/unloading, we present a probabilistic risk model, appraised with empirical data. The model integrates probabilistic exposure profiles from a compartmental lung model with the reconstructed dose-response relationships based on an empirical three-parameter Hill equation model, describing AFB1 cytotoxicity for inhibition response in human bronchial epithelial cells, to quantitatively estimate the inhalation exposure risks. The risk assessment results implicate that exposure to airborne AFB1 may pose no significance to corn harvest and grain elevator loading/unloading activities, yet a relatively high risk for swine feeding and storage bin cleaning. Applying a joint probability function method based on exceedence profiles, we estimate that a potential high risk for the bronchial region (inhibition=56.69% with 95% confidence interval (CI): 35.05-72.87%) and bronchiolar region (inhibition=44.93% with 95% CI: 21.61 - 66.78%) is alarming during swine feeding activity. We parameterized the proposed predictive model that should encourage a risk-management framework for discussion of carcinogenic risk in occupational settings where inhalation of AFB1-contaminated dust occurs. ? 2005 Elsevier Ltd. All rights reserved.