<\/p>\n
ABS: The Triad approach represents an evolution and progression of technical thinking about contaminated sites. Triad serves as a platform to integrate the experiences, lessons learned, and advances in science and technical tools and know-how gained over the past 25+ years of hazardous site investigation, cleanup, and reuse.<\/p>\n
The Purpose of the Triad Approach<\/p>\n
Experienced practitioners from the public and private sectors have pooled their efforts to create the Triad approach. This scientific effort is supported by EPA to foster modernization of technical practices for characterizing and remediating chemically contaminated sites. The goal of the Triad approach is to manage decision uncertainty, that is, to increase confidence that project decisions (about contaminant presence, location, fate, exposure, and risk reduction choices and design) are made correctly and cost-effectively. (\u201cCorrect\u201d decisions are here defined as the decisions that would be made if fully completely accurate knowledge of contamination nature and extent and receptor exposure were available to decision-makers.) The foundation for site-related decisions that are both correct and optimized (from a cost-benefit standpoint) is the conceptual site model (CSM). A CSM uses all available historical and current information to estimate<\/p>\n
\u2022 where contamination is (or might be) located,<\/p>\n
\u2022 how much is (or might be) there, \u2022 how variable concentrations may be and how much spatial patterning may be present,<\/p>\n
\u2022 what is happening to contaminants as far as fate and migration,<\/p>\n
\u2022 who might be exposed to contaminants or harmful degradation products, and<\/p>\n
\u2022 what might be done to manage risk by mitigating exposure.<\/p>\n
As a primary Triad product, an accurate CSM will distinguish and delineate different contaminant populations for which decisions about risk and remediation will differ. Distinguishing between different contaminant populations improves the quality and interpretation of data, as well as the confidence and resource effectiveness of project decisions. Triad achieves sufficiently accurate CSMs by proactively identifying and managing decision uncertainties (i.e., those unknowns that stand in the way of making confident decisions) and data uncertainties (sources of variation in data results when decisions are based on data). These tasks are accomplished by incorporating advanced science and technology tools into the project toolbox.<\/p>\n
The Triad approach represents an evolution and progression of technical thinking about contaminated sites. Triad serves as a platform to integrate the experiences, lessons learned, and advances in science and technical tools and know-how gained over the past 25+ years of hazardous site investigation, cleanup, and reuse. It was developed through the efforts of practitioners dedicated to perfecting the science and art of site characterization and cleanup, despite recognizing the difficulties posed by the fundamentally heterogeneous nature of contaminated sites. Triad supports second-generation practices that, although somewhat different from current practices, truly sustain all three benchmarks of \u201cbetter, faster, and cheaper\u201d projects (Crumbling, et al 2003). The Triad approach is a scientific and technical initiative, not a regulatory approach, although it is hoped that regulatory bodies will take note of advancing scientific knowledge and technical capability and integrate them into their regulatory frameworks.<\/p>\n
The Elements of the Triad Approach<\/p>\n
\u201cTriad\u201d is not an acronym, and should not be written to appear as one. The word is intended to convey that there are three elements. The most important element of the Triad, systematic project planning (called \u201cstrategic planning\u201d by some), supports the ultimate Triad goal of confident decision-making. To ensure high decision confidence and stakeholder satisfaction (\u201cbetter\u201d projects) Triad encourages developing:<\/p>\n
\u2022 \u201csocial capital\u201d (i.e., an atmosphere of trust, transparent, open communication, and cooperation between parties working toward a protective, yet cost-effective resolution of the \u201cproblem\u201d);<\/p>\n
\u2022 consensus on the desired outcome (i.e., end goal) for the site\/project;<\/p>\n
\u2022 a preliminary CSM from existing information;<\/p>\n
\u2022 a list of the various regulatory, scientific and engineering decisions that must be made in order to achieve the desired outcome;<\/p>\n
\u2022 a list of the unknowns that stand in the way of making those decisions (i.e., decision uncertainties);<\/p>\n
\u2022 strategies to eliminate, reduce, or \u201cmanage around\u201d those unknowns; and<\/p>\n
\u2022 proactive control over the greatest sources of uncertainty in environmental data (i.e., sampling-related variables such as sample volume and orientation, particle size, sampling density, subsampling, etc.).<\/p>\n
The second element, dynamic work strategies, is the element that allows projects to be completed \u201cfaster\u201d and \u201ccheaper\u201d than ever possible under traditional, static work strategies. Work planning documents written in a dynamic or flexible mode guide the course of the project to adapt in real-time (i.e., while the work crew is still in the field) as new information becomes available. This allows preliminary CSMs to be tested and evolved to maturity (i.e., sufficiently complete to support the desired level of decision confidence) in real-time, saving significant time and money while supporting better resolution of uncertainties. A valuable aspect of dynamic work strategies, focused quality control (QC) that adapt in real-time (a form of \u201cprocess\u201d QC), makes analytical QC procedures more relevant and powerful than what is possible with traditional work static strategies with the analytical operator far removed from field involvement.<\/p>\n
Lastly, the third Triad element, real-time measurement technologies, makes dynamic work strategies possible by gathering, interpreting, and sharing data fast enough to support real-time decisions. The range of technologies supporting real-time measurements includes field analytical instrumentation, in situ sensing systems, geophysics, rapid turn-around from traditional laboratories, and computer systems that assist project planning, and store, display, map, manipulate, and share data. Although field analytical methods are usually less expensive to operate than fixed laboratory analyses, under the Triad analytic budgets will generally be the same or even higher than conventional. Sample densities are increased to manage the various factors contributing to sampling uncertainty. This allows highly accurate and detailed CSMs to be built as the foundation of confident decision-making. In the big picture, per-sample costs are much less important to the financial bottom-line than are the real-time, confident decisions that so dramatically lower the life-cycle costs of Triad projects.<\/p>\n
An ideal Triad project would strongly rely on each element. But we do not live in an ideal world, and \u201cthe perfect should not the enemy of the good,\u201d as the saying goes. Especially when project teams are first learning Triad concepts and attempting to blend technology and strategy tools into a Triad project,<\/p>\n
it should not be expected that all Triad projects will be equally strong in every element. However, there are a few basic features that define a Triad project:<\/p>\n
\u2022 consensus on clearly worded project goals and intended decisions (with expressions of what decision errors are tolerable and which are not) for field work before it begins,<\/p>\n
\u2022 a CSM that anticipates site-specific heterogeneities and contaminant distributions,<\/p>\n
\u2022 strategies to refine the CSM over the course of the project in relation to the intended decisions, and<\/p>\n
\u2022 discussions about the mechanisms to manage sampling and analytical uncertainties in data collection.<\/p>\n
These features are so fundamental to Triad that if they are lacking from planning or from project documents, a claim for a Triad project is suspect. The advantages offered by dynamic work strategies, high sampling densities and real-time refinement of the CSM to lower costs and increase decision confidence make them highly desirable, and Triad projects will naturally include them to the extent feasible. But the degree to which they are employed is not distinctive, since it will vary depending on many technical and logistical factors, not the least of which include regulatory, budgetary, contracting and legal constraints and the expertise of the project team.<\/p>\n
Summary<\/p>\n
The hazardous waste cleanup arena is changing as a result of 20-30 years of scientific, engineering, and regulatory experience. There are more options for effective remediation than ever before. But a common theme is that accurate site characterization is mandatory for cleanup technologies to perform efficiently. The generation of site data must be designed to produce a CSM that reliably portrays nature and extent of contamination in relation to the intended compliance and cleanup decisions. A data set that is representative of exposure risk probably will not be representative of decisions about remedial design. A data set useful to a remedial design that functions on larger spatial scales (such as thermal oxidation) will probably not be effective for designing a remedy that functions over a smaller spatial scale (such as chemical oxidation). Designs to generate data must take these factors into account from the start, or resources are wasted gathering irrelevant information. Or worse, the nonrepresentative data are not recognized as such and remedial design is based on faulty information, practically guaranteeing that remedial systems will be less than optimally effective. The Triad approach is but one example of the smarter work strategies now available. But coordinated effort and determination will be required to address the multitude of institutional barriers stemming from community inertia and out-of-date regulatory guidance.<\/p>\n","protected":false},"excerpt":{"rendered":"