The Need

Close scrutiny of environmental cleanup efforts is becoming a focus of many action groups, ranging in diversity from governmental advisory groups to local stakeholders. Given the large financial impact of environmental remediation and its importance to human and ecological health, it becomes critical that:

• cleanup policies be based upon the best available science

• remediation is managed to achieve the least risk to the public

• remediation decisions be effectively communicated to risk managers and to the public

• environmental cleanup maximizes the safety benefit for a given financial investment

The Ernest Orlando Lawrence Berkeley National Laboratory has created the SELECT project, an initiative involving the Energy & Environment, Earth Sciences, Life Sciences and Information & Computing Sciences divisions.

The SELECT project brings together scientists who work together on methods to manage environmental cleanup systematically, making possible cost-effective decisions based on comparative risk analysis. The goal of the SELECT initiative is to design and develop a flexible, PC-based, object-oriented software system that will integrate, analyze, and present environmental information to managers, engineers, scientists, regulators, and the public. It will assist these users in selecting cost-effective environmental remediation strategies based on scientifically sound risk analysis. SELECT primarily focuses on (1) cost-effective environmental remediation based on comparative health-risk analysis of alternative remediation strategies, and (2) information visualization tools that enhance communication among stakeholders.

The initiative was spawned from the scientific advances that Berkeley lab scientists made through DOE-supported research such as OHER's radon research program, OBES's geosciences program, and the radioactive waste program. This DOE-developed core competency encompasses subsurface site characterization, contaminant transport and exposure models, estimates of cancer risk from contaminant exposure, and the evaluation and improvement of remediation effectiveness, technologies, and strategies. A number of features distinguish SELECT from similar activities elsewhere: its modeling of actual physical processes (as opposed to regulatory processes), focus on human health risk reduction in a comparative context, and ability to incorporate the most up-to-date scientific knowledge.

The Vision

• an integrated, scientific assessment of an environmental problem that can be continually updated with the most advanced computational methods,

• decision tools that primarily focus on selecting cost-effective environmental remediation that maximizes health-risk reduction, and

• information visualization tools that will enhance communication with stakeholders.
  
  

SELECT Integrates Science into Environmental Decision Making

The SELECT methodology will be embodied in a distributed, object-oriented computational framework that integrates state-of-the-art scientific advances in:

• site characterization,

• subsurface and atmospheric transport processes,

• exposure analysis,

• health-hazard assessment, including comparisons of estimated upper-bound cancer risks from background exposures with potential upper-bound risks from exposures at the contaminant site, and

• the financial cost of environmental remediation.

SELECT Provides Tools to Visualize the Effects of Alternative Strategies

A series of visualizations illustrates the movement of a water front over time through a porous media containing a uniform distribution of hydrocarbon.

As time passes and the water front moves through the media, the region behind the moving water front is oil-free. The chemical concentrations are computed by a finite-difference simulation used to model chemical flooding.

Current Status of the SELECT Project

The SELECT methodology has been incorporated into a prototype simulation. This prototype simulates the current and future states of a contaminant plume over time for each remediation alternative being considered. This is followed by estimating the exposures of a residential population to the contaminant. Using rodent carcinogenic potency values and exposure estimates, including (often profound) estimates of uncertainty, potential cancer risk is estimated. Where possible, pharmacokinetic analyses of cancer risk are incorporated. Possible cancer hazards are compared to similarly estimated hazards from typical exposure to rodent carcinogens, e.g., to natural chemicals in the diet, which are common background exposures. Costs associated with a specific remediation action are integrated with risk estimates to identify cost-effective strategies. Secondary risks produced by remediation are also evaluated. Information visualization tools are used to reduce the information to an understandable form that site managers can use to formulate strategic plans and that the public and other stakeholders can readily understand.

A 10 minute demonstration of the current version (SELECT P1) of the interface can be viewed here.

Future Development of the SELECT Project

• Completion of a comprehensive uncertainty analysis
• Inclusion of all major VOCs
• Development of a robust economics model
• Inclusion of metals and radionuclides
• Expansion to include reproductive and ecological risks

At present, the SELECT methodology incorporates evaluation of uncertainties due to parameter uncertainty and due to exposure population heterogeneity. We will extend the uncertainty analyses for additional components of SELECT (e.g., cancer potency), and will begin to develop new methods for dealing with the overall uncertainties that arise from linking many different kinds of models--from transport to cancer potency--each of which are formulated differently. Currently, there is no consensus approach for comprehensive treatment of key sources of uncertainty in estimates of cancer potency for most rodent carcinogens, even though such uncertainty may dominate all other sources of uncertainty. We plan to develop a flexible method to reflect chemical specific uncertainties, based on widely available rodent-bioassay and related evidence upon which assumptions regarding carcinogenicity and cancer potency are currently predicated. Methods for estimating overall uncertainties for SELECT present a challenging scientific problem that will have applications to other integrated assessment models.

What YOU Can Do to Help with This Important Effort