Society For Risk Analysis Annual Meeting 2013

Session Schedule & Abstracts

* Disclaimer: All presentations represent the views of the authors, and not the organizations that support their research. Please apply the standard disclaimer that any opinions, findings, and conclusions or recommendations in abstracts, posters, and presentations at the meeting are those of the authors and do not necessarily reflect the views of any other organization or agency. Meeting attendees and authors should be aware that this disclaimer is intended to apply to all abstracts contained in this document. Authors who wish to emphasize this disclaimer should do so in their presentation or poster. In an effort to make the abstracts as concise as possible and easy for meeting participants to read, the abstracts have been formatted such that they exclude references to papers, affiliations, and/or funding sources. Authors who wish to provide attendees with this information should do so in their presentation or poster.

Common abbreviations

Fuel, Asbestos, Dust, Spores & Death

Room: Key Ballroom 5   3:30 PM - 5:10 PM

Chair(s): Shawn Sager

Sponsored by EASG

M4-E.1  15:30  Specific Consumer Exposure Determinants (SCEDs) for fuel and lubricant scenarios. Zaleski RT*, Qian H, Money CM, Rohde A; ExxonMobil Biomedical Sciences Inc., CONCAWE

Abstract: Under REACH, classified substances produced in more than 10 tons per year require the development of exposure scenarios to ensure the safe use conditions of the substance and, further, communicate these conditions in the supply chain. The European Centre for Ecotoxicology and Toxicology of Chemicals Targeted Risk Assessment tool (ECETOC TRA) is a preferred screening tier exposure model for REACH, to assist in identifying safe use conditions. Consistent with REACH, the TRA is intentionally parameterized with conservative defaults for a broad range of consumer product uses. Because of the inherent conservatism of REACH process, much industry effort has been dedicated to better understanding consumer exposure determinants and strengthening the documentation and public availability of information supporting their basis. As part of the revised TRAv3 (released in 2012), ECETOC developed the concept of Specific Consumer Exposure Determinants (SCEDs) to facilitate the delivery of more realistic estimates of consumer exposure. The SCED enables industrial sector groups and trade associations to use available information on consumer use habits and practices to further refine the consumer exposure estimate for the product/substance. Based on recent public data, we have developed 9 SCEDs to cover a range of consumer fuel use scenarios and 4 SCEDs to better describe consumer lubricant use scenarios. The changes to the TRA defaults in these SCEDs help to more accurately describe current consumer uses in practice while retaining a conservative approach to the assessment of risk presented by each scenario. The Downstream Users of Chemical Coordination group (DUCC) is extending this concept to compile a library of SCEDs covering a range of consumer product sectors. The intent are that these materials, which will be public, can better describe the nature of current consumer exposures through various tools such as the TRA and the European Chemical Agency’s Chemical Safety Assessment and Reporting tool (CHESAR).

M4-E.2  15:50  Cumulative Exposures to Asbestos Fibers from Dropped Ceiling Installation and Maintenance. Boelter FW*, Xia Y, Persky JD; ENVIRON International

Abstract: Dropped ceilings began around 1940s to be used in commercial and to a lesser degree residential construction for better acoustics, modern appearance, reduction of heating and lighting costs, and compatibility with then-new suspended fluorescent lighting. Several fatal fires including the 1958 Our Lady of the Angels fire in Chicago in which combustible building materials including acoustic tiles were accused of costing loss of life, hastened the inclusion of fireproof asbestos in interior building materials until the mid to late 1970s. We developed an algorithm for the reconstruction of exposures to airborne asbestos fibers resulting from ceiling tile activities and implemented the algorithm using hypothetical work histories for five categories of people – specialty construction contractors, general building contractors, Do-It-Yourself nonprofessionals (DIYer), maintenance trades, and bystanders. We present new exposure data obtained through two field studies on asbestos-containing ceiling tiles removal and replacement and one chamber study involving cutting and installing such tiles. These data, coupled with professional judgment and mathematical modeling (Bayesian decision analysis and stochastic simulation), lead to the estimations of 8 h time-weighted average (TWA) as well as 1-year and 10-year cumulative exposures to asbestos fibers from working with asbestos-containing ceiling tiles. Our results estimate mean 1-year cumulative exposure expressed as f/cc-years to be 0.007 for specialty construction contractors, 0.0004 for general building contractors, 0.00008 for Do-It-Yourself nonprofessionals, 0.004 for maintenance trades, and 0.0004 for bystanders. The distributions of 8 h TWA dust and asbestos fiber exposures estimated for the five worker categories are compared to historical exposure data, while the cumulative exposure estimates are used to evaluate health risks. None of the five categories of workers receive a cumulative exposure (dose) that would significantly increase their risk for disease development.

M4-E.3  16:10  Evaluation of a simple steady-state model: estimating resuspended particles in indoor air. Nemickas H, Sager* S*, Navon D, Hubbard T; ARCADIS

Abstract: This presentation evaluates a screening-level methodology used to quantify potential inhalation of resuspended constituents present on surfaces within buildings. The U.S. Army Center for Health Promotion and Preventative Medicine, Technical Guide 312, Health Risk Assessment Methods and Screening Levels for Evaluating Office Worker Exposures to Contaminants on Indoor Surfaces Using Surface Wipe Data (TG 312) includes methodology to estimate particulate concentrations in indoor air based on resuspension from contaminated surfaces. The simple steady-state model accounts for the rate at which surface contaminants are resuspended into the air, loss due to deposition, and air exchanges in the building or room. TG 312 documents the uncertainties associated with estimating resuspended particulate concentrations, recognizing there are numerous factors that affect resuspension of surface particles. While no quantitative relationships between surface wipe concentrations and concurrent air concentrations have been reported, the most common way to estimate particles resuspended from a surface is to use empirical or estimated resuspension factors (i.e., ratio of air concentration to surface concentration) from the literature. Differences between surface wipe data and concurrent air concentrations that range over six orders of magnitude have been reported. The simple steady-state model, while incorporating deposition loss and air exchange, ultimately relies on a resuspension factor to estimate air concentrations. Empirical data collected during the renovation work at one site indicated air concentrations closely matched (i.e., within an order of magnitude) air concentrations estimated using the simple steady-state model. Surface wipe and indoor air data from multiple sites will be used to evaluate this simple steady-state model for different constituents and under different building conditions. Potential implications for application of the methodology will be discussed.

M4-E.4  16:30  A risk model for inhaled toxins and spores associated with Stachybotrys chartarum. Prasad B*, Sunger N, Lennon E; Drexel University

Abstract: Stachybotrys chartarum, a black mold frequently present in damp indoor environments, has been well-characterized due to its ability to produce human toxins such as trichothecene. The inhalation exposure to S. chartarum has been implicated in cases of acute idiopathic pulmonary hemorrhages (AIPH) in infants. The goals for this study were (1) to determine the risk of death in human infants using the maximum reported concentration of toxins and spores in an average water-damaged residential unit and (2) to determine the levels at which S. chartarum might pose as an acceptable risk. Studies of experimental administration of S. chartarum spores or trichothecene toxin on young animals were selected to model the dose response relationship between exposure and probability of death. The best-fit dose-response models for the threshold data were the Log-logistic for S. chartarum spores as exposure indicator in infant rats, and the Weibull for the trichothecene toxin in young mice. Stochastic risk estimates were developed using the proposed dose-response models to predict the risk of death in infants exposed to spores or toxins via inhalation. Analysis results showed that there is significantly high daily risk for acute 24-hour exposure to toxins ranging from 1 in 10,000 to 3 in a million. For a 10% daily risk based on inhalation instillation, the acceptable level of human equivalent dose in environmental samples was 413 spores/m3 or 3.94E-05 mg-toxin/m3. Sensitivity analysis was conducted using Monte Carlo simulations to identify factors that are highly correlated with risk estimates. This study indicates that S. chartarum toxin exposure via inhalation in indoor environments may cause a risk for AIPH, but a conclusive epidemiology study is needed to validate the risk estimates. However, the conclusion of insignificant health risk to infants in moldy indoor environments is based on spore quantification and may under-report the disease burden associated with this fungi.

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