Development of Nationwide Excess Lifetime Cancer Risk Evaluation Methods with Comprehensive Past Asbestos Exposure Reconstruction

Abstract

Although exposure to asbestos via various routes has been acknowledged, comprehensive exposure and risk assessment methods have not been developed at the national level. We conducted a study to reconstruct comprehensive past asbestos exposure estimations and to suggest a method to calculate the Excess Lifetime Cancer Risk (ELCR) of Koreans. The past occupational exposure reconstruction was conducted by rebuilding the previous general population job-exposure matrix (JEM). The para-occupational and household exposure estimation was based on the pooled analysis of data from other countries as well as Korea. The neighborhood exposure from occupational sources by distance was estimated by the exponential decay model. As a result, 141 JEM exposure groups across four periods including ~79, the 80s, 90s, 2000s with a ratio of 2.0:1.0:0.5:0.05 were reconstructed. The para-occupational and household exposures were 11% and 1% of the JEM respectively. The environmental exposure source concentration from outside occupational exposure was 2.5% of the inside concentration. The ratio of the concentration of environmental exposure source (C0) to distance d (Cd) was exp-kd with a decay constant k of 6.834. The mean concentrations (f/cc) were 2.28 × 10−3 for outdoor, 4.65 × 10−5 for indoor, 1.95 × 10−2 for transportation activity, 4.44 × 10−2 for agricultural activity, and 4.68 × 10−2 for daily life activity in naturally occurring asbestos areas. Indoor and outdoor asbestos concentrations from living in a slate roof house were 1.73 × 10−6 and 2.70 × 10−8, respectively. For improved generalizability, validity, and applicability of the proposed method, further studies on each route with real assessments and experiments are required.

Development of New Health Risk Assessment of Nanoparticles: EPA Health Risk Assessment Revised

“…Nevertheless, nanoparticle toxicity can lead to different diseases or can induce negative effects within the human body, where cancer represents one of the leading diseases that causes death. Currently, the state-of-the-art method for such calculations is based on the EPA (U.S. Environmental Protection Agency) health risk assessment, which is still being used even in recent publications [ 53 ]; for substances of categories A, B1, and B2 it is calculated as follows: where ELCR represents the excess lifetime cancer risk, the EC value (µg·m −3 ) is the exposure concentration of the substance and IUR represents the inhalation unit risk ((μg·m −3 ) −1 ). It is evident that this methodology treats the toxic agent in terms of the homogeneous concentration of the toxic agent (as a simple soluble compound or gas).…”