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

SRA 2013 Annual Meeting Abstracts
T1-E.4 Furukawa, K; Radiation Effects Research Foundation;
furukawa@rerf.or.jp
A Bayesian semi-parametric dose response estimation in
radiation risk assessment
Characterizing the dose effect relationship and estimating
acceptable exposure levels are the primary goal of quantitative
risk assessments. In analysis of health risks associated with
exposure to ionizing radiation, while there is a clear agreement
that moderate to high radiation doses cause harmful effects in
humans, we have insufficient information to understand the
possible biological effects at low doses, e.g., doses below 0.1
Gy. A conventional approach to dose response analyses tends to
base inference on an idealized model that is chosen primarily
due to the lack of statistical power, which may be misleading in
characterizing the low dose effects and, especially, estimating
their uncertainties. As an alternative approach, this study
proposes a Bayesian semi-parametric model that has a
piecewise linear dose response function with auto-regressive
priors as a smoother, applied to data grouped in closely spaced
dose categories. A simulation study shows that the proposed
approach can yield relatively robust and efficient estimations
under various situations assuming dose response relationships
that are often considered as possible models of radiation
oncogenesis at low doses. The new approach is applied to the
cancer incidence data of the Life Span Study cohort of Japanese
atomic bomb survivors, which has long been an important data
source for developing quantitative estimates of risk from
exposure to radiation.
W3-F.5 Fusco, MP; Global Catastrophe Research Institute;
markpfusco@gmail.com
Christian Apocalyptic Literature in Theological
Scholarship & The 'Prepper' Movement
There has been an increase in the number and variety of
movements in the United States that are preparing for a global
catastrophic event. The motivation inspiring these ‘preppers’ is
as varied as their understanding of how future scenarios
(political, social, environmental, extraterrestrial, technological,
biological, etc.), will necessarily lead to devastation on the
global level. Each of these approaches provides data points
given its unique methods and interpretative frameworks.
Preppers often take their interpretation and projection of hard
scientific data as being commensurate with their religious
presuppositions. In the presentation we will outline how
theological scholarship understands the scriptural account of
the last days as recorded in the book of Revelation, as one
means to frame a conversation with preppers.
T3-E.1 Gaborek, BJ; Bellin, CA; Dellarco, M; Egeghy, P; Heard,
N; Jensen, E; Lander, DR; Tanir, JY*; Zaleski, RT; Sunger, N;
DuPont ; jtanir@hesiglobal.org
Optimizing a Tiered Exposure Framework to Aid Risk
Assessment Decision-Making
The science of risk assessment is utilized on a world-wide basis
by regulatory authorities and industry to protect the health and
welfare of humans and the environment from a broad range of
chemicals, biological materials, and consumer products. Risk
assessment is based on evaluating both the hazard
(toxicological impact) and the exposure (likelihood and
frequency of contact) components of risk, most often in a
quantitative manner. During the last several years, exposure
has been incorporated earlier and more prominently into the
risk assessment process. In addition, numerous organizations
across the globe have initiated a “tiered” approach to utilizing
exposure data. Generally in a tiered exposure assessment, the
first quantified estimates are deterministic and tending toward
overestimation. These lower tier exposure estimates are often
useful in screening or prioritizing additional efforts. With
advancement to higher tiers, the estimates become
progressively less conservative and more certain.
Consequently, these exposure predictions often facilitate
decision-making at a more chemical or product-specific level.
As part of the ILSI Health and Environmental Sciences
Institute’s RISK21 initiative, the Exposure Science Sub-team
focused on developing a novel, streamlined, and tiered
approach for estimating exposure that maximizes use of readily
available information (existing approaches, tools, and data) and
that aligns with available hazard data. The goal of this effort
was to identify efficiencies that, if implemented in risk
assessment, would facilitate quicker decision-making and focus
resources in areas with greatest information value. As an
introduction to subsequent presentations in this symposium,
this discussion introduces the proposed framework, briefly
compares it to other tiered frameworks, and then describes the
Tier 0 level of the framework with some degree of detail. This
abstract does not necessarily reflect U.S. EPA policy.
P.24 Gadagbui, B; Maier, A; Nance, P*; JayJock, M; Franklin, C;
Toxicology Excellence for Risk Assessment; nance@tera.org
A Decision Tool for Assessing Polymers and Polymeric
Substances with Potential Hazards to Human Health
Polymers display a wide variety of characteristics - e.g.,
presence of non-bound residual monomers, polymerization
chemicals, degradation products, and additives - that may pose
a potential health hazard. There is a paucity of direct testing
data on many polymers to adequately evaluate their toxicity,
but several regulatory agencies have provided guidance for
assessing polymer safety. We evaluated each of these
approaches and identified the strengths and weaknesses of
each. No single published model appears to cover all
characteristics of interest. This suggests the need to develop a
comprehensive decision tool to identify polymeric substances
that may pose potential toxicological hazards to human health.
We developed a decision tool that incorporates a weight of
evidence approach integrating information for many individual
hazard flags. Hazard flags were placed into four broad
categories: (1) empirical hazard information on the polymer or
residual monomer; (2) evidence of toxicity based on structural
properties (i.e., based on polymer class, monomer components,
or reactive functional groups); (3) potential for significant
tissue dose (i.e., based on molecular weight distribution or
systemic bioavailability); and (4) hazard based on foreseeable
special use considerations. Some of these hazard flags have not
been considered previously by the regulatory agencies. We
tested this approach for a number of polymers to demonstrate
how the new tool (integrates) incorporates all available
regulatory approaches as well as the new features and provides
a comprehensive decision framework for evaluating polymer
safety.
December 8-11, 2013 - Baltimore, MD