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

SRA 2013 Annual Meeting Abstracts
W2-K.3 Salazar, DE*; Chatterjee, S; University of Southern
California; danielsalazaraponte@gmail.com
Managing risk through resilience and recovery in seaport
operations
Port operations are vital for the welfare of the country,
supporting food security and economic activity. Arguably,
natural hazards constitute the main threat to port operations,
although intentional attacks can inflict significant damage too.
Depending on the importance of each port and its exposure to
risk, different strategies for risk management are possible.
However, in some cases and due to the criticality of certain
locations, resilience should be enhanced to secure at least some
minimal level of operation capacity in the aftermath of a
disaster. Although some frameworks for allocation of resources
in critical infrastructure protection have been published, they
pay more attention to prevention than resilience and recovery.
In this research we focus on what to do in the aftermath of a
disaster. We present a methodology to assess resilience in port
operations using statistical and simulation modeling methods
for risk and operability assessment and decision analysis tools
for resource allocation.
M2-D.1 Sasso, AF*; Schlosser, PM; US Environmental
Protection Agency; sasso.alan@epa.gov
A harmonized PBPK model of hexavalent chromium in
rats and mice
Hexavalent chromium (Cr(VI)) is an environmental and
occupational contaminant, and is present in both soil and
drinking water in the United States. In 2-year drinking water
bioassays, the National Toxicology Program found clear
evidence of carcinogenic activity in male and female rats and
mice. Because reduction of Cr(VI) to Cr(III) is an important
detoxifying step that can occur in the gastrointestinal (GI) tract
prior to systemic absorption, numerous physiologically-based
pharmacokinetic (PBPK) models have been developed over the
past two decades to estimate inter-species differences in
toxicity. While the currently available models adequately
simulate the available dietary and drinking water datasets
available for Cr(VI) and Cr(III), intravenous and gavage data
were typically not evaluated. Due to uncertainties related to the
kinetics and absorption of Cr(VI) in the GI tract, data for other
routes of exposure provide valuable toxicokinetic information.
Furthermore, all previous kinetic models for GI reduction
assume a single pathway is responsible for the reduction of
Cr(VI) to Cr(III), which does not capture the underlying
complexities of GI reduction kinetics. The current work
attempts to 1) harmonize assumptions between alternate prior
PBPK models, 2) adequately simulate data for different routes
of exposure and study designs, and 3) incorporate a revised
model for GI reduction kinetics (which assumes multiple
parallel reduction reactions). The potential impacts on future
human health risk assessments will be discussed. The views
expressed are those of the authors, and do not necessarily
represent the views or policies of the U.S. EPA.
P.16 Sax, S*; Prueitt, R; Goodman, J; Gradient;
ssax@gradientcorp.com
Weight-of-Evidence Evaluation of Short-term Ozone
Exposure and Cardiovascular Effects
There is a considerable body of research on the cardiovascular
(CV) effects associated with ozone exposure, including
epidemiology, toxicology, and controlled human exposure
studies. US EPA is considering these data to determine whether
to update the ozone National Ambient Air Quality Standards
(NAAQS). We conducted a weight-of-evidence (WoE) analysis to
determine if there was an association between CV effects and
short-term ozone exposures at levels below the current primary
ozone NAAQS of 75 parts per billion. Our analysis followed an
updated WoE framework based on EPA's NAAQS framework.
We found that the epidemiology evidence of CV morbidity and
mortality is inconsistent and lacks coherence across specific CV
endpoints. Specifically, the lack of epidemiology evidence of
morbidity effects is not coherent with reported mortality
estimates. Toxicology studies, although somewhat more
consistent, are conducted at high exposure levels well above
the current NAAQS, and there is limited information on
dose-response relationships. Furthermore, there is a lack of
coherence between reported results from epidemiology studies
(suggesting no effects) and results from animal studies
(suggesting small effects at high exposure levels). Similarly,
controlled human exposure studies report inconsistent effects
after exposure to high ozone levels above the current NAAQS.
Overall, our WoE analysis indicates that CV effects are not
associated with short-term ozone exposures below the current
NAAQS.
W4-D.5 Sayes, CM; RTI International; csayes@rti.org
Life cycle considerations for nano-enabled products
containing multiwalled carbon nanotubes (MWCNTs):
Research to inform future risk analyses and risk
management
Engineered nanomaterials can bring great advantages to the
development of sustainable products in multiple industries
(e.g., construction, textile goods, sporting equipment). For
example, multiwalled carbon nanotubes (MWCNTS) can
increase the resistance of construction materials to aging (UV,
mechanical stress, etc.), particularly when used as a coating.
Risk analyses can inform the dynamic development of MWCNTs
used in this industry by providing information to risk managers
on potential MWCNT risks to humans and the environment.
Risk assessors can use a product life cycle perspective to better
inform risk managers about critical considerations in the
development of safe nanomaterials, such as MWCNTs. To carry
out these analyses, risk assessors need data from researchers
on product development and manufacturing, exposure
(consumer and occupational) and human and environmental
impacts of MWCNT-enabling technologies. The objective of this
talk is to present the most recent environmental health and
safety findings on MWCNTs incorporated into current and
emerging products. Specifically, this talk outlines our data on:
1) production of unique nanocomposites for products, 2)
characterization methods for nano-enabled products, and 3)
exposures and hazards to nanocomposites during the
production phase. Information presented here will support an
interactive discussion on what additional data in these areas
would most facilitate risk analyses that use a product life cycle
perspective to inform subsequent risk management decisions
about MWCNTs.
December 8-11, 2013 - Baltimore, MD