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Abstracts (PDF file, 1.8MB) - Society for Risk Analysis

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SRA 2013 Annual Meeting <strong>Abstracts</strong><br />

P.136 BRACCA, M; MONZON, A; DEMICHELIS, SO*;<br />

ENVIRONMENT LABORATORY - DDPYT - UNLA;<br />

sandrademichelis@yahoo.com<br />

Bad decisions increases health risks: reopening of an<br />

abandoned asphalt plant a case of study.<br />

The overall goal of this work is to diminish risk by planning the<br />

recovery of use and the habitat remediation of an abandoned<br />

asphalt plant (now micro-dump) belonging to the municipality<br />

of Lanus. The site is surrounded by housing and obsolescence<br />

and waste is an environmental liability that requires early<br />

intervention, After EIS, recommended the elimination of<br />

landfill, neutralization of obsolete material, the relocation of the<br />

asphalt plant and soil remediation. The situation analysis<br />

concludes that the ground is not suitable <strong>for</strong> development and<br />

operation of plant and waste and debris existence justifies its<br />

intervention. The government proposed not to move the plant,<br />

but reactivate. The negative impacts will occur on human<br />

health in case of reopening are associated with the appearance<br />

of asphalt fumes, with immediate consequences <strong>for</strong> those<br />

exposed directly and increased risk of various cancers. As <strong>for</strong><br />

the environmental and health damage existing waste cause pest<br />

invasion, air pollution, leachate generation that pollute<br />

groundwater The transfer proposal showed investment will be<br />

much more expensive than the reopening; however, these do<br />

not include the health costs it will generate <strong>for</strong> government<br />

since public health is covered by state; there<strong>for</strong>e preventive<br />

measures are proposed as the relocation of the plant is better<br />

than reopening, by clearing the dump and the property,<br />

remediation of soil gas extraction methods and aeration will<br />

result in diminish damages. At present authorities prefers<br />

reopen it but they did not per<strong>for</strong>m EIS. If the proposal of<br />

eradication fails and the reopening of the plant will take place,<br />

a program that includes surveillance and mitigation must be<br />

developed.<br />

T4-J.2 Brand, K; University of Ottawa; kbrand@uottawa.ca<br />

Outcome in<strong>for</strong>med Departures from a Default Science<br />

Policy Assumption<br />

Default assumptions are integral to chemical risk assessments,<br />

serving to bridge knowledge-gaps that would otherwise derail<br />

quantitative assessment. Each default assumption generally<br />

enjoys both an evidential base (establishing it as a reasonable<br />

approach <strong>for</strong> filling its respective knowledge-gap) and a policy<br />

sanction of being more likely to err on the side of caution.<br />

Under certain circumstances a departure from a default<br />

assumption (e.g., one concerning dose-response relationship<br />

shape) may be both warranted and championed; the focus of<br />

the champion being upon avoiding the prospect of ``regulatory<br />

overkill'' whereby excessive and undue regulatory costs stem<br />

from the adoption of an unwarranted default. The question of<br />

an appropriate standard of proof to demand be<strong>for</strong>e warranting<br />

such a departure has been the source of longstanding<br />

discussion. In this talk I offer a standard expected utility (SEU)<br />

framework <strong>for</strong> in<strong>for</strong>ming this question. Under the SEU<br />

framework a sliding scale is prescribed as the appropriate<br />

standard of proof, and revealed to depend centrally upon the<br />

ex-ante outcomes that hinge upon the choice (between the<br />

default and alternative assumption). The implications of this<br />

framework <strong>for</strong> future deliberations over whether to depart from<br />

a default assumption are discussed as are some of the<br />

challenges that may be posed when implementing it in practice.<br />

T3-B.3 Brewer, LE*; Teushler, L; Rice, G; Wright, JM; Neas, L;<br />

ORISE Fellow in the Research Participation Program at the U.S.<br />

EPA, Office of the Science Advisor (LEB); U.S. EPA, National<br />

Center <strong>for</strong> Environmental Assessment (LT, GR, JMW); U.S. EPA,<br />

National Health and Environmental Effects Research<br />

Laboratory(LN); brewer.beth@epa.gov<br />

Using directed acyclic graphs in cumulative risk<br />

assessment (CRA)<br />

CRA is an emerging scientific approach <strong>for</strong> integrating human<br />

heath and ecological risks from aggregate exposures to<br />

physical, biological, chemical, and psychosocial stressors. A<br />

shift in emphasis from the traditional single-chemical risk<br />

assessment paradigm to community-focused assessments that<br />

combine risks from chemical and non-chemical stressors would<br />

benefit from a structured analysis of the potential pathways<br />

linking cause and effect. Directed acyclic graphs (DAGs) depict<br />

causal associations and provide an improved method <strong>for</strong><br />

communicating complex relationships linked by quantitative or<br />

qualitative data. Rules <strong>for</strong> constructing DAGs are more rigorous<br />

than <strong>for</strong> conceptual models typically created in the problem<br />

<strong>for</strong>mulation phase of a risk assessment, and a simple algorithm<br />

applied to the graph allows <strong>for</strong> the identification of confounders<br />

that is critically important to causal inference. As<br />

stressor-effect pathways are further elucidated through<br />

literature review and data collection, the DAG can be revisited<br />

and modified resulting in a model representative of the best<br />

evidence available <strong>for</strong> risk estimation. A DAG can there<strong>for</strong>e be<br />

utilized in three phases of CRAs: to identify potential<br />

confounders in planning, scoping, and problem <strong>for</strong>mulation; to<br />

clarify assumptions and illustrate the weight of evidence<br />

approach in the analysis phase; and to communicate risks to<br />

stakeholders and decision-makers in a clear, transparent<br />

manner. In sum, DAGs provide the strong logical structure<br />

necessary <strong>for</strong> understanding the complex causal relationships<br />

among stressors and effects, and <strong>for</strong> assessing cumulative risks<br />

to human health and the environment. (The views expressed in<br />

this abstract are those of the authors and do not necessarily<br />

reflect the views or policies of the U.S. EPA.)<br />

M2-D.3 Brinkerhoff, CJ*; Salazar, KD; Lee, JS; Chiu, WA; Oak<br />

Ridge Institute <strong>for</strong> Science & Education, Oak Ridge, TN;<br />

ORD/NCEA-IRIS, US EPA, Washington DC; ORD/NCEA-IRIS, US<br />

EPA, Research Triangle Park, NC; brinkerhoff.chris@epa.gov<br />

Development of a PBPK Model <strong>for</strong> ETBE and TBA in Rats<br />

and Its Application to Discern Relative Contributions to<br />

Liver and Kidney Effects<br />

Ethyl tert-butyl ether (ETBE) is an oxygenated gasoline<br />

additive. ETBE is rapidly absorbed and metabolized to<br />

acetaldehyde and tert-butyl alcohol (TBA). Published studies <strong>for</strong><br />

both ETBE and TBA in rats have reported liver and kidney<br />

effects including increased organ weights, and nephropathy.<br />

The magnitudes of these effects vary by chemical and route of<br />

exposure. Additionally, exposure to ETBE by inhalation<br />

produced an increased incidence of liver adenomas in male<br />

rats, but ETBE delivered in drinking water or TBA in drinking<br />

water did not. This difference could be due to the higher<br />

internal dose of ETBE in the inhalation study compared to the<br />

ETBE and TBA drinking water studies. A physiologically-based<br />

pharmacokinetic (PBPK) model could estimate internal doses to<br />

aid in interpreting these differences in effect however there are<br />

no existing models of ETBE in rats or of direct administration of<br />

TBA. We have developed and applied a PBPK model of ETBE<br />

and TBA in rats. The PBPK model was parameterized with<br />

toxicokinetic data in rats from iv and inhalation studies of TBA<br />

and from oral and inhalation studies of ETBE. The PBPK model<br />

was used to make quantitative comparisons of the internal<br />

blood concentrations of ETBE and TBA associated with kidney<br />

and liver effects. The dose-response relationships <strong>for</strong> ETBE<br />

blood concentration and liver adenoma incidence across<br />

inhalation and oral routes support the hypothesis that the<br />

differences in the incidence of liver adenomas are due to<br />

differences in internal dose of ETBE. The model is also being<br />

used to evaluate differences between administered and<br />

metabolized TBA in dose-response relationships <strong>for</strong><br />

nephropathy and kidney and liver weight changes. The views<br />

expressed in this abstract are those of the authors and do not<br />

necessarily represent the views or policies of the U.S.<br />

Environmental Protection Agency or other affiliations.<br />

December 8-11, 2013 - Baltimore, MD

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