[Federal Register Volume 68, Number 70 (Friday, April 11, 2003)]
[Notices]
[Pages 17797-17800]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-8951]


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ENVIRONMENTAL PROTECTION AGENCY

[FRL-7481-5]


Science Advisory Board; Request for Nominations for Experts for a 
Panel on Multimedia, Multipathway, and Multireceptor Risk Assessment 
(3MRA) Modeling System

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice.

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SUMMARY: The Environmental Protection Agency Science Advisory Board 
(SAB) is announcing the formation of a new panel regarding the 
Multimedia, Multipathway, and Multireceptor Risk Assessment (3MRA) 
Modeling System and soliciting nominations for membership on this 
panel.

DATES: Nominations should be submitted no later than May 2, 2003.

ADDRESSES: Nominations should be submitted in electronic format through 
the Form for Nominating Individuals to Panels of the EPA Science 
Advisory Board provided on the SAB Web site. The form can be found at 
http://www.epa.gov/sab/sab_panel_form.htm. To be considered, all 
nominations must include the information required on that form. Anyone 
who is unable to submit nominations via this form may contact Ms. 
Kathleen White, Designated Federal Officer (DFO), as indicated below.

FOR FURTHER INFORMATION CONTACT: Any member of the public wishing 
further information regarding this Request for Nominations may contact 
Ms. Kathleen White, (DFO), U.S. EPA Science Advisory Board (1400A), by 
telephone/voice mail at (202) 564-4559, by fax at (202) 501-0582; or 
via e-mail at [email protected].

SUPPLEMENTARY INFORMATION:
    1. Summary: The Environmental Protection Agency (EPA) Science 
Advisory Board (SAB) is announcing the formation of a new Panel to 
review the technical validity of the Multimedia, Multipathway, and 
Multireceptor Risk Assessment (3MRA) Modeling System for setting 
national risk-based regulations on the waste program. The SAB is 
soliciting nominations to establish the members of the new Panel.
    This Panel is being formed to provide advice to the Agency, as part 
of the EPA SAB's mission, established by 42 U.S.C. 4365, to provide 
independent scientific and technical advice, consultation, and 
recommendations to the EPA Administrator on the technical bases for EPA 
decision making. The Board is a chartered Federal Advisory Committee, 
which reports directly to the Administrator.
    2. Background: There have been substantial efforts by Federal and 
State organizations and the private sector to develop risk assessment 
tools that include the evaluation of contaminants in different media 
and the integration of exposures across pathways to help establish an 
integrated risk-based assessment.
    In December 1995, EPA's Office of Solid Waste proposed to amend 
existing regulations for disposal of listed hazardous wastes under the 
Resource Conservation and Recovery Act (RCRA). The December 1995 
proposal (60 FR 6634, December 21, 1995) outlined the Hazardous Waste 
Identification Rule (HWIR) that was designed to establish constituent-
specific exit levels for low risk solid wastes that are currently 
captured in the RCRA subtitle C hazardous waste system. Under this 
proposal, waste generators of listed wastes that could meet the new 
concentration-based criteria defined by the HWIR methodology would no 
longer be subject to the hazardous waste management system specified 
under subtitle C of RCRA. This would have established a risk-based 
``floor'' for low risk hazardous wastes that would encourage pollution 
prevention, waste minimization, and the development of innovative waste 
treatment technologies.
    In May and June of 1995, EPA's Science Advisory Board (SAB) 
reviewed the proposed HWIR methodology for calculating exit 
concentrations and in May 1996 published its findings in Review of a 
Methodology for Establishing Human Health and Ecologically Based Exit 
Criteria for the Hazardous Waste Identification Rule (HWIR) (EPA-SAB-
EC-96-002), available at http://www.epa.gov/sab/pdf/ec96002.pdf. In 
addition to this review, EPA's Office of Research and Development 
(ORD), and numerous industrial and environmental stakeholders, also 
reviewed the proposed methodology. While the SAB concluded that the 
methodology ``lacks the scientific defensibility for its intended 
regulatory use,'' the SAB also made the following recommendations that, 
when addressed, should provide an adequate scientific basis for 
establishing a risk-based methodology applicable at the national level 
for the waste program:
    (a) Develop a true multi-pathway risk assessment in which a 
receptor receives a contaminant from a source via all pathways 
concurrently, is exposed to the contaminant via different routes, and 
accounts for the dose corresponding to each route in an integrated way;
    (b) Maintain mass balance;
    (c) Conduct substantial validation of the methodology and its 
elements, against actual data derived from either the laboratory or 
field, prior to implementation of the model;
    (d) Conduct a systematic examination of parameters to ensure a 
consistent and uniform application of the proposed approach, and 
further, the full suite of uncertainties to be addressed for the final 
methodology;
    (e) Discard the proposed screening procedure for selecting the 
initial subset of chemicals for ecological analysis and instead require 
that a minimum data set

[[Page 17798]]

be satisfied before ecologically based exit criteria are calculated;
    (f) Seek the substantive participation, input, and peer review by 
Agency scientists and outside peer review groups as necessary, to 
evaluate the individual components of the methodology in much greater 
detail; and,
    (g) Reorganize and rewrite the documentation for both clarity and 
ease of use.
    As a result of the methodology reviews, the Office of Solid Waste 
(OSW) collaborated with the Office of Research and Development (ORD) to 
develop and document a sound science foundation, supporting data for an 
assessment, and related software technology for an integrated, 
multimedia modeling system (entitled 3MRA) following the 
recommendations of the SAB and other reviewers. This effort was 
initiated with the peer review of an integrated research and 
development plan (ORD/OSW Integrated Research and Development Plan for 
the Hazardous Waste Identification Rule (HWIR), 1998 available at: 
http://www.epa.gov/epaoswer/hazwaste/id/hwirwste/risk.htm), that 
describes the assessment methodology, the technical bases for the 
integrated multimedia modeling system, and quality controls to be 
followed during the developmental process. The Multimedia, 
Multipathway, and Multireceptor Risk Assessment (3MRA) modeling system 
represents a collection of science-based models and databases that have 
been integrated into a software infrastructure that is based on the 
FRAMES (Framework for Risk Analysis in Multimedia Environmental 
Systems) concept, which provides a computer-based environment for 
linking environmental models and databases and managing the large 
amounts of information within the system, including the visualization 
of outputs. This integrated multimedia modeling system provides 
national-level estimates of human and ecological risks resulting from 
long-term (chronic) chemical release from land-based waste management 
units. Over 45 experts participated in the peer review process of the 
underlying science within the 3MRA modeling system.
    The EPA plans to use the modeling system to help inform managers on 
a variety of decisions in the waste program, such as setting 
concentration-based exit criteria for wastes in the hazardous waste 
management regulations, or deciding whether technology-based standards 
are protective of human health and the environment.
    3. Proposed Charge to the Panel: The EPA is asking the SAB to focus 
its review in the following four areas: assessment methodology, 3MRA 
modeling system, modeling system evaluation, and modeling system 
documentation. Charge questions related to those areas are identified 
in the relevant section below.

Assessment Methodology

    The 3MRA assessment methodology presents a strategy for estimating 
national distributions of human and ecological risks resulting from 
long-term (chronic) chemical release from land-based waste management 
units. The national distribution is constructed by performing ``site-
based'' assessments at a statistically significant number of randomly 
sampled hazardous waste site locations across the U.S. In the 
assessment methodology, a pollutant is released from a waste management 
unit to the various media (air, water, soil) according to its chemical 
properties and characteristics of the unit. The pollutant is 
transported through the media and exchanged between media via system 
linkages. Receptors are exposed concurrently to the pollutant via 
multiple pathways/routes resulting in an integrated dose.
    The methodology describes a tiered approach for populating data 
files for each site evaluation. The approach is referred to as ``site-
based'' because the assignment of data values for the site being 
simulated occurs according to a tiered protocol. Data values are filled 
first with data at a site level; when site data are not available, a 
statistically sampled value from a geographically relevant regional 
distribution of values are used; and lacking a representative regional 
distribution for the variable, a value from a national distribution is 
assigned.
    The 3MRA methodology was designed specifically to include Monte 
Carlo simulation methods to address both uncertainty and variability in 
the risk outputs. Statistical distributions for many modeling 
parameters were developed and upon implementation provide a statistical 
measure of variability and uncertainty, i.e., the range and 
distribution of potential exposures and risks occurring at a site. When 
applied to the sites in a national assessment, the result is a 
statistical measure of variability and uncertainty, and national 
distributions of risks. The sites currently in the database are 
randomly selected from sites across the United States to represent the 
national variability in waste management scenarios and locations. The 
methodology for selecting the sites allows for measures of protection 
to be calculated at the site level and aggregated over all the sites to 
develop the national distribution of risks.
    Charge Question 1: While the EPA had the assessment methodology 
peer reviewed prior to the development of the 3MRA modeling system, 
does the SAB have any additional comments about the methodology as 
implemented?

3MRA Modeling System

    To implement the 3MRA methodology, the EPA chose to develop a 
comprehensive software-based modeling system, which facilitates the 
consistent use of sound-science models through a framework that 
controls model sequencing, facilitates data exchange, and provides data 
analysis and results visualization tools. Following modern Object 
Oriented software design and development principles and honoring the 
use of legacy models (i.e., fate and transport models that have a long 
history of use at the EPA), the EPA has constructed a modern modeling 
system that facilitates the consistent and reproducible application of 
the 3MRA modules and databases to problems requiring a national-scale 
assessment of site-based risks. The 3MRA modeling system is underpinned 
by a software infrastructure named FRAMES. FRAMES provides a computer-
based environment for linking and applying environmental models and 
managing the large amounts of information within the system.
    The 3MRA modeling system consists of: (a) 17 science-based modules 
that estimate chemical fate, transport, exposure, and risk; (b) 7 
system processors that select data for model execution; manage 
information transfer within the system; ``roll-up'' site-based results 
into distributions of risk at the national level; and provide a 
visualization of the system outputs; and (c) multiple databases that 
(currently) contain the data for waste managements sites across the 
country as well as regional and national distributions of data values, 
(d) a software infrastructure (framework) based on FRAMES.
    The 3MRA system was designed to provide flexibility in producing 
distributions of hazards or risks at sites that may manage exempted 
waste because the final regulatory decision framework for defining 
chemical-specific exit levels has not been formulated. The system is 
designed to allow the evaluation of human health impacts to the general 
population or selected subpopulations and the impact of varying the 
measures of protection at different probability levels. The system

[[Page 17799]]

has similar capabilities with respect to evaluating the impacts on 
ecological systems.
    Charge Question 2a: Does the 3MRA modeling system provide a tool 
for performing national risk assessments that facilitates consistent 
use of the science and provides a mechanism for reproducing results?
    Charge Question 2b: Does the 3MRA modeling system provide decision-
makers sufficient flexibility for understanding the impacts on 
potential chemical exemption levels by allowing varying measures of 
protection based on the number of receptors and/or number of sites 
protected, types of human and ecological receptors, and distance?
    Charge Question 2c: Does the 3MRA modeling system provide 
appropriate information for setting national risk-based regulations for 
the waste program?

Modeling System Evaluation

    In response to the SAB recommendation that substantial evaluation 
of the modeling system is essential to building confidence in the 
system, the EPA focused significant efforts to ensure the scientific 
integrity of the 3MRA system and its results during system development 
and post-development. The EPA designed and implemented rigorous quality 
assurance and quality control procedures for software development, data 
collection, verification testing, and peer review on the scientific 
components of the system.
    The EPA implemented specific steps to build a level of confidence 
in the system to ensure that the system will present a reasonable 
estimate of nationwide risk for a national-level assessment.
    First, the overall technical approach and each science-based module 
included in 3MRA have been peer reviewed. Teams of peer reviewers (at 
least three per module) provided critical feedback about the science-
based modules. All told, over 45 independent experts reviewed the 
science modules to ensure that the theoretical concepts describing the 
processes within release, fate, transport, uptake, exposure, and risk 
components were adequate representations of the processes to be 
evaluated.
    Second, all software components and databases underwent a series of 
tests to verify that the software and data were performing properly. At 
the heart of this protocol is the requirement that each component of 
the modeling system include a designed and peer reviewed test plan that 
is executed by both the model developer and a completely independent 
modeler (i.e., someone who did not participate in the original model 
development). These procedures, test plans, test packages, and test 
results are fully documented and available to the public.
    Third, a comprehensive data collection approach was developed to 
parameterize the modeling system in accordance with the site-based 
approach described in the assessment methodology. This data collection 
plan described the general collection methodology for the major types 
of data (for example, facility location, land use, soil 
characteristics, receptor locations), including quality assurance and 
quality control procedures and references for data sources. Fourth, the 
3MRA modeling system has undergone a comparison analysis with EPA's 
Total Risk Integrated Methodology (TRIM) that is currently under 
development. The objective of the model comparison effort was to 
increase confidence that the 3MRA modeling system produces estimates 
consistent with other multi-media models.
    While complete validation of a modeling approach would be the 
ultimate proof for a multimedia system like the 3MRA, the EPA did not 
find a multimedia data set to compare with the system's predictive 
outputs. In addition, the model comparison study was conducted using an 
actual industrial site where environmental monitoring data for mercury 
representing the relationship between contaminant source and 
environmental concentrations were available (albeit an incomplete set 
of observational data). Finally, a formal program focusing on 
sensitivity and uncertainty analysis for high-order modeling systems 
has been initiated at ORD. The early focus of this program is the 
investigation of parameter sensitivities and system uncertainties 
within the 3MRA modeling system. A supercomputer has been configured to 
allow exhaustive experimentation with the 3MRA system in Monte Carlo 
mode. Initial results of these efforts have been documented.
    Charge Question 3a: Is the software development and verification 
testing approach implemented for the 3MRA modeling system sufficient to 
ensure confidence that the modeling results reflect the modeling system 
design?
    Charge Question 3b: Given the thorough evaluations that EPA has 
implemented using the available data resources and technologies, while 
also recognizing the real world limitations that apply to validating 
the 3MRA modeling system, have we reasonably demonstrated through 
methodology design, peer review, quality control, sensitivity analyses, 
and model comparison, that the 3MRA modeling system will produce 
scientifically sound results of high utility and acceptance with 
respect to multimedia regulatory applications?

3MRA Modeling System Documentation

    In response to significant comments regarding the lack of clarity 
and transparency associated with documentation of the earlier modeling 
system the EPA has devoted significant time and resources to correcting 
this limitation. The 3MRA represents a comprehensive risk assessment 
capability and as such integrates the science from all contributing 
disciplines. Documentation is necessarily voluminous. In preparing the 
current documentation our intent is to provide different levels of 
presentation depending on the intended audience. The EPA has prepared a 
significant number of reports and documents at various levels of 
technical complexity that describe the 3MRA modeling system and the 
related HWIR application.
    The review documents consist of a four volume set of documents, 
providing a comprehensive overview of the 3MRA modeling system. These 
documents are intended to be the primary means by which the general 
public would become familiar with the 3MRA system and are also intended 
to provide the level of information necessary for a risk assessor to 
make an informed decision regarding the applicability of the 3MRA 
modeling system to specific risk assessment problems.
    Charge Question 4: Has the EPA made substantive progress, relative 
to 1995, in designing and preparing documentation for the 3MRA modeling 
system? Does the SAB have additional suggestions for improving the 
presentation of the comprehensive set of materials related to this 
modeling system?
    4. Development Plan Document Available: For the purpose of enough 
understanding about the 3MRA modeling system to nominate candidates, 
the reader may find the ORD/OSW Integrated Research and Development 
Plan for the Hazardous Waste Identification Rule (HWIR), 1998 helpful. 
This document introduces the policy and technical issues shaping the 
development of the 3MRA modeling system. This document is available at: 
http://www.epa.gov/epaoswer/hazwaste/id/hwirwste/risk.htm.
    5. SAB Request for Nominations: Any interested person or 
organization may nominate qualified individuals for Membership on the 
Subcommittee.

[[Page 17800]]

Individuals should have expertise in one or more of the following 
areas:

(a) Integrated Software Technology for Multimedia Modeling
(b) Sensitivity and Uncertainty Analyses for Higher Order Environmental 
Models
(c) Quality Assurance and Model Evaluation
(d) Integrated Multimedia Fate and Transport Modeling--air focus
(e) Integrated Multimedia Fate and Transport Modeling--surface water 
focus
(f) Integrated Multimedia Fate and Transport Modeling--groundwater 
focus
(g) Integrated Multimedia Fate and Transport Modeling--food chain focus
(h) Integrated Modeling for Human and Ecological Risk Assessments
(i) National Probabilistic Risk Assessment using Monte Carlo-based 
Methods
(j) Properties of Chemicals and Environmental Media
(k) Nation-wide Risk Assessments
(l) Human toxicology
(m) Ecological toxicology
(n) Risk Communication
(o) Familiarity with hazardous waste regulations and remediation 
technologies.

    6. Process and Deadline for Submitting Nominations: Any interested 
person or organization may nominate qualified individuals to add 
expertise in the above areas for the Panel. Nominations should be 
submitted in electronic format through the Form for Nominating 
Individuals to Panels of the EPA Science Advisory Board provided on the 
SAB Web site. The form can be found at http://www.epa.gov/sab/sab_panel_form.htm. To be considered, all nominations must include the 
information required on that form.
    Anyone who is unable to submit nominations using this form may 
contact Ms. Kathleen White at the mailing address in the section above 
entitled, FOR FURTHER INFORMATION CONTACT. Nominations should be 
submitted in time to arrive no later than May 2, 2003. Any questions 
concerning either this process or any other aspects of the notice 
should be directed to Ms. White.
    The EPA Science Advisory Board will acknowledge receipt of the 
nomination and inform nominators of the panel selected. From the 
nominees identified by respondents to this Federal Register notice 
(termed the ``Widecast''), SAB Staff will develop a smaller subset 
(known as the ``Short List'') for more detailed consideration. Criteria 
used by the SAB Staff in developing this Short List are given at the 
end of the following paragraph. The Short List will be posted on the 
SAB Web site at: http://www.epa.gov/sab, and will include, for each 
candidate, the nominee's name and their biosketch. Public comments will 
be accepted for 21 calendar days on the Short List. During this comment 
period, the public will be requested to provide information, analysis 
or other documentation on nominees that the SAB Staff should consider 
in evaluating candidates for Panel.
    For the EPA SAB, a balanced review panel (i.e., committee, 
subcommittee, or panel) is characterized by inclusion of candidates who 
possess the necessary domains of knowledge, the relevant scientific 
perspectives (which, among other factors, can be influenced by work 
history and affiliation), and the collective breadth of experience to 
adequately address the charge. Public responses to the Short List 
candidates will be considered in the selection of the panel, along with 
information provided by candidates and information gathered by EPA SAB 
Staff independently on the background of each candidate (e.g., 
financial disclosure information and computer searches to evaluate a 
nominee's prior involvement with the topic under review). Specific 
criteria to be used in evaluating an individual subcommittee member 
include: (a) Scientific and/or technical expertise, knowledge, and 
experience (primary factors); (b) absence of financial conflicts of 
interest; (c) scientific credibility and impartiality; (d) availability 
and willingness to serve; and (e) ability to work constructively and 
effectively in committees.
    Short List candidates will also be required to fill-out the 
``Confidential Financial Disclosure Form for Special Government 
Employees Serving on Federal Advisory Committees at the U.S. 
Environmental Protection Agency'' (EPA Form 3110-48). This confidential 
form, which is submitted by EPA SAB Members and Consultants, allows 
Government officials to determine whether there is a statutory conflict 
between that person's public responsibilities (which includes 
membership on an EPA Federal advisory committee) and private interests 
and activities, or the appearance of a lack of impartiality, as defined 
by Federal regulation. The blank form may be viewed and downloaded from 
the following URL address: (http://www.epa.gov/sab/pdf/epaform3110-48.pdf). Subcommittee members will likely be asked to attend two public 
face-to-face meetings and several public conference call meetings over 
the anticipated course of the review. The face-to-face meetings are 
likely to be in the July, August, September timeframe.

    Dated: April 4, 2003.
Vanessa T. Vu,
Director, EPA Science Advisory Board Staff Office.
[FR Doc. 03-8951 Filed 4-10-03; 8:45 am]
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