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Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory: Final Report 6 Findings and Recommendations This chapter summarizes the committee’s findings and recommendations developed in Chapters 3, 4, and 5 of this report. Los Alamos National Laboratory’s (LANL’s) current groundwater protection program began under mandate from the New Mexico Environment Department (NMED) in 1998, and it is to be completed by 2015 according a Consent Order issued by NMED. To help ensure a timely and successful completion, the Department of Energy (DOE) requested the National Academies to provide technical advice on certain technical aspects of the program. The committee’s statement of task is given in Sidebar 1.1. Because the groundwater protection program is at about its midpoint, the committee viewed it as a work in progress, and this report is necessarily a snapshot in time. The committee’s findings are based on information presented by LANL and other stakeholders through about April 2007. The committee’s recommendations are directed toward improving the effectiveness of the program and providing a sound scientific basis for LANL’s future remedial actions and long-term monitoring. OVERARCHING FINDINGS LANL’s groundwater protection program faces substantial technical challenges. There is considerable uncertainty about the contamination sources themselves. The pathways for transport of contaminants from their sources include four different hydrologic regimes: (1) surface streams and runoff, (2) near-surface groundwater in the canyon alluvium, (3) intermediate-perched groundwater in the unsaturated (vadose) zone, and (4) a deep, regional aquifer. Each of these regimes adds considerable uncertainty to the understanding of the overall system. Even with best efforts to understand contaminant sources and pathways, the uncertainty will always be great. Nevertheless, LANL has no other options except to advance its program in the face of uncertainty. Surprises will be inevitable in this learning process. On the positive side, LANL scientists learned a good deal through the Hydrogeologic Workplan, which was conducted from 1998 to 2005 (LANL, 2005a). While the thickness of the vadose zone and the depth of the regional aquifer, some 1000 feet, make their scientific study difficult, these features are assets for groundwater protection. The substantial relief provided by the canyons that cut through the volcanic sequence provides a good conceptual picture of the site’s geology. The direction of surface and groundwater flow is generally known, even if the identification of the specific pathways is problematic. Regardless of the difficulties that lie ahead, prudence and the law require that a groundwater monitoring system be established. The recommendations in this report support the proposition that it is technically feasible to monitor the groundwater. The efficacy of the monitoring system will have to be determined based on the analysis of the future data that will be obtained as the system is developed. There are four overarching findings that arose from the committee’s study and that have relevance to essentially all parts of the task statement. Geochemistry LANL demonstrated substantial progress in site characterization under the Hydrogeologic Workplan. However, LANL’s work in geochemistry has not kept pace with work in hydrogeology.1 Geochemistry is central to understanding the extent to which contaminants move with groundwater; it is a tool for better understanding hydrogeologic pathways; and it is essential for determining the degree to which monitoring data are representative of actual groundwater. The specific need is to understand how contaminant migration caused by 1 Water is primarily responsible for the migration of contaminants. Hydrogeology is the study of groundwater behavior in the subsurface. Geochemistry is the study of the chemical properties of the solid materials of the Earth, and in this case would include how contaminants interact with these materials and groundwater.
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Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory: Final Report groundwater is affected by geologic or anthropogenic media that are encountered along the groundwater’s flowpath. The committee saw few fundamental, site-specific studies that quantitatively address this need. Conducting such studies in the laboratory is not difficult, but it requires dedicated scientific effort to plan and conduct appropriate tests and to interpret their results. Mass Balance LANL needs better ways to demonstrate its considerable understanding—and eventually its mastery—of potential threats to the regional aquifer. Specifically this means knowing the site’s inventory of contaminants and where they are.2 Most contaminants are evidently still in or near their sources; a sizeable fraction of some have migrated into the vadose zone; and a small fraction are in the regional aquifer. This information needs to be quantified and presented succinctly. The committee judged that mass balance is an appropriate tool for this purpose.3 Mass balances, which LANL has begun developing for a few disposal areas (Birdsell et al., 2006), could be developed for other high-inventory areas and integrated to eventually account for contaminants sitewide. Such accounting for contaminants is the essence of groundwater protection, and it can help foster trust among LANL, its regulators, and public stakeholders. Uncertainty Uncertainty is inherent in scientific knowledge, and work to address uncertainty leads to improved knowledge. LANL needs to do a better job of describing uncertainties in its groundwater protection program to both scientific and public audiences. This includes describing fundamental conceptual uncertainty—things that are simply not known, such as the nature of some groundwater pathways—and measurement uncertainty, such as the variability of laboratory results for contaminants detected at very low levels. The committee judged that greater openness about uncertainty—on the parts of LANL and its stakeholders—could improve the quality and transparency of LANL’s groundwater protection program. Peer Review Peer review is the standard of science. The committee is not hesitant to take LANL’s motto: “The World’s Greatest Science Protecting America” at face value. However, like many publications from DOE laboratories, LANL reports typically fall in the area of non-peer-reviewed literature. LANL has produced massive amounts of report material, and the additional step of summarizing and publishing key portions, as it did with some information from the Hydrogeologic Workplan (VZJ, 2005), can help authenticate LANL’s groundwater protection program. This is not to discount LANL’s other peer-reviewed publications from the program, but rather to encourage more. Besides peer-reviewed literature, other venues are available for peer review of important work that is not amenable to journal publication.4 Demonstrations of sound science through peer review will go a long way toward ensuring the effectiveness of LANL’s groundwater protection program and enhancing confidence among stakeholders. FINDINGS AND RECOMMENDATIONS TO ADDRESS THE TASK STATEMENT This section gives the detailed findings and recommendations developed in the main text of this report according to the task statement. Findings and Recommendations on Sources of Contamination and Source Controls Radioactive or chemically hazardous wastes disposed onsite at LANL constitute the sources of contamination that the committee considered in addressing its statement of task. These sources are the inputs from which contaminants enter the soils, rocks, and water that comprise the hydrogeologic environment beneath the LANL site. The Laboratory has practiced onsite disposal of its wastes since the early 1940s. Disposal methods include the discharge of liquid effluents into canyons and the emplacement of solid wastes, mainly on mesa tops.5 The committee’s statement of task posed three questions regarding sources: What is the state of the Laboratory’s understanding of the major sources of groundwater contamination originating from Laboratory operations and have technically sound measures to control them been implemented? 2 LANL does not need a detailed inventory of each and every possible contaminant. Based on information presented to the committee, chromium, nitrates and high-explosive residues, perchlorate, and radionuclides appear to be most important. Others are listed in the Consent Order and DOE regulations. 3 The elements of mass balance are discussed in Chapter 3. 4 It may not always be the case that detailed, site-specific groundwater protection work will rise to the level of novel methods or results of broad interest (outside of the communities affected by LANL or DOE practices) that is often a prerequisite for journal publication, or the work might simply be too detailed or lengthy for a typical journal article of 4-12 published pages. However, even routine aspects of this work would benefit from some type of outside peer review. There are alternatives for peer review. For example, the Española Basin Technical Advisory Group includes 12 organizations (including LANL) that consider the Española Basin a primary groundwater resource. This advisory group has objectives of developing strategies for integration and coordination of technical studies and information transfer. Such an organization is an example of an appropriate venue for peer review of groundwater protection studies that would not lend themselves to peer-reviewed journal articles. See http://esp.cr.usgs.gov/ebtag/About.html. 5 Discharges of gaseous effluents are not considered in this report.
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Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory: Final Report Have potential sources of non-Laboratory groundwater contamination been identified? Have the potential impacts of this [non-Laboratory] contamination on corrective-action decision making been assessed? The committee’s short answer to the first question is yes for liquid sources and no for solids. Liquid waste discharges are generally eliminated or controlled. LANL’s data indicate that previous liquid discharges were the sources of contamination currently found in groundwater. However, solid wastes and contaminants deemed by LANL to have less near-term potential to impact groundwater have received much less attention than the liquid sources and are not well understood, especially in terms of source inventories. The short answer to the second question is a qualified yes. The answer to the third has to be no because LANL is only beginning to determine corrective actions under the Consent Order. This aspect of decision making was not discussed with the committee. The committee offers the following findings and recommendations to assist LANL in future work to understand and control its contamination sources, with emphasis on longer-term concerns that have not been addressed during the first portion of the groundwater protection program. Solid wastes, e.g., the 25 material disposal areas (MDAs), and certain contaminants deemed by LANL to be essentially immobile (e.g., Pu) have the potential for impacting groundwater in the future. MDA AB in Technical Area-49 (TA-49), which contains some 2300 Ci of Pu-239, is an example. The committee received little information that would provide assurance that these sources are well understood or well controlled. Recommendation: LANL should complete the characterization of major contaminant disposal sites and their inventories, i.e., complete the investigation of historical information about these disposal sites with emphasis on radionuclides and chemicals likely to impact human health and the environment. Selected sites should be characterized by field analysis when historical information is insufficient to determine quantities of major contaminants disposed and to confirm the degree of transport that has occurred. LANL should devote greater effort to characterizing sources with significant inventories of contaminants (especially plutonium) that usually are strongly sorbing but still have the long-term potential to migrate in the presence of water. Priority for investigating sources is established by the Consent Order. This recommendation emphasizes the need to confirm assumptions that underpin the assignment of lower priority to “immobile” wastes. There are still large uncertainties in LANL’s estimates of the inventories of principal contaminant sources and their locations. Similarly, analyses are lacking to approximate the current locations of contaminants (which may have migrated from these sources) in the various hydrogeological units that constitute the LANL site and surrounding areas. Recommendation: For the major disposal sites, LANL should develop mass balance estimates of the quantities of disposed chemicals and radionuclides remaining in the surface soil and/or residing in the shallow alluvium, the vadose zone, and the regional aquifer. Sitewide, LANL should perform a mass balance for hazardous and radioactive substances by assessing the types, quantities, and volumes of individual hazardous materials that have entered the site over the years.6 These analyses, with estimates of data uncertainties, should help LANL account for contaminant sources, releases, radioactive decay, and migration through the hydrogeologic system in a way that is transparent and understandable to all of its stakeholders. Surface water is an important pathway for transport of contaminants to the groundwater. Stormwater can remobilize contaminants that have been deposited in canyons and transport them downstream. The contaminants can enter the shallow groundwater away from their original source or be transported offsite. Recommendation: LANL needs to quantify the inventories of contaminants released in the canyons in order to understand their potential threat to groundwater. The sitewide mass balance of inventories of hazardous and radioactive substances should include the surface water transport pathway. LANL should continue to develop surface water and sediment monitoring programs. LANL should continue, and improve, its control of contaminants moving down the canyons to prevent further surface transport and redistribution offsite of both mobile and sorbing contaminants. Measures to control surface transport down canyons, including further reduction of aqueous discharges, removal of contaminated media, and appropriate use of barriers, are needed. 6 When taking mass loss mechanisms into account (e.g., radioactive decay rates), this will identify the upper boundary of pollutant mass that may still exist at the site today.
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Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory: Final Report The geochemistry of contaminant migration has not been studied at a level of detail comparable to the site investigations conducted under the Hydrogeologic Workplan. This is a gap in LANL’s current groundwater protection program. Recommendation: LANL should better integrate geochemistry into its conceptual modeling. Laboratory experiments and field tests, in addition to literature data, are necessary to substantiate LANL’s general observations and assumptions about the geochemical behavior of contaminants. LANL will continue to be an active DOE site with the potential for release of contaminants from its ongoing operations. Discharges and releases have been cut substantially at TA-50, the location of the site’s radioactive liquid waste treatment facility. Yet, its discharges will continue to provide a flow of water that will tend to remobilize contaminants already deposited in the canyons. Recommendation: LANL should continue to review all operations and reduce discharges and releases to the greatest extent practical. This includes efforts to minimize the disposal of solid wastes on mesa tops because waste disposal in those areas can pose a long-term threat to the regional groundwater. Findings and Recommendations on Contaminant Pathways and the Interim Monitoring Plan LANL carried out its Hydrogeologic Workplan from 1998 through 2004 to better characterize the site’s hydrogeology and the potential pathways for contaminant transport. The purpose of the characterization program was to develop the scientific basis for a sitewide groundwater monitoring plan. The committee’s statement of task posed two questions regarding LANL’s current (interim) monitoring program: Does the laboratory’s interim groundwater monitoring plan follow good scientific practices? Is it adequate to provide for the early identification and response to potential environmental impacts from the laboratory? Is the scope of groundwater monitoring at the laboratory sufficient to provide data needed for remediation decision making? If not, what data gaps remain, and how can they be filled? After reviewing LANL’s Interim Facility-wide Monitoring Plan7 the committee answered the two parts of item 1 with a qualified yes and no, respectively. While the Interim Plan generally follows good scientific practices, there are opportunities for improving it. The plan is not adequate to provide early identification of potential contaminant migration with high confidence because LANL’s understanding of pathways for contaminant transport, especially inter-watershed pathways, is not yet adequate to support such confidence. The committee answered item 2 with a qualified no. Findings and recommendations to assist LANL address remaining gaps in pathway conceptualizations and improve its monitoring plans are as follows: The current conceptualization of the LANL flow system into alluvial, intermediate-perched, and regional components, along with their importance to understanding the flow system within and below wet canyons, is a major accomplishment by LANL scientists. However, there is a lack of understanding of the interconnectedness of pathways between basins. While there is a general understanding that perched waters are probably redirecting contaminants from areas directly below canyons where they originally infiltrate, to submesa areas and to other nearby canyons, the detailed knowledge needed to predict subsurface flowpaths does not exist. Lack of understanding of these phenomena, coupled with rapid flow in the alluvium and apparent rapid flow facilitated by perched waters, was central to the surprise over detection of chromium near the water supply wells. An improved knowledge of these inter-watershed processes is needed to design an effective, early warning monitoring program. Recommendation: LANL should add a sitewide perspective to its future groundwater monitoring plans. This perspective would include the following: Design additional characterization, modeling, and geochemical investigations to better understand potential fast pathways between watersheds. Increase the area of the regional aquifer that is monitored by sampling inter-canyon areas from mesas or using directional wells from canyon bottoms. Provide additional monitoring locations in the southern area of the site and on Pueblo de San Ildefonso lands. Develop more applications of geophysical techniques to supplement information provided by well drilling and sampling, especially for understanding vadose zone pathways. As LANL’s site characterization and monitoring programs mature, well locations should be derived from a quantitative spatial analysis of monitoring well locations to identify areas with the greatest uncertainty in plume concentrations, using geostatistics or other methods, possibly coupled with flow and transport modeling. 7 The Interim Monitoring Plan was subsequently included as section 1 in LANL’s 2006 Integrated Sitewide Monitoring Plan (LANL, 2006a). Three additional sections dealt with offsite monitoring and monitoring to satisfy the conditions of two discharge permits. These additions did not affect the committee’s review or its findings or recommendations.
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Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory: Final Report Mathematical models are essential tools for both codifying current knowledge and identifying knowledge gaps. Although LANL is using a numerically sophisticated multiphase model for vadose and regional groundwater modeling, it is not yet possible to predict with confidence when, where, or if a contaminant might appear in the regional aquifer. This is due largely to an exceptionally complex vadose zone. Studies show that most of the mass of many contaminants is likely still in the vadose zone on the way down from the release location to the regional aquifer. Recommendation: LANL should increase its efforts to develop and use quantitative methods to describe contaminant pathways through the vadose zone and into the regional aquifer, as follows: Mathematical models that incorporate the uncertainties from alternative conceptual models should underpin plans for design and operation of the sitewide monitoring system. Characterization of the vadose zone begun under the Hydrogeologic Workplan should continue with emphasis on new results from characterization and monitoring being used to test and improve the mathematical models. To support an evaluation of the effectiveness of the monitoring system to provide early warning of potential impacts on the regional aquifer, LANL should quantify, to the extent possible, the inventory and current location of the contaminants disposed of in the major waste sites. Large waste disposal sites in the dry canyons and on dry mesas have not received as much attention as wet canyons and wet mesas because they presumably lack an aqueous driver to move contamination. The presumed dry locations have received minimal characterization with regard to the presence, strength, and potential impact of aqueous drivers. In some of these, surface disturbances have led to unexpected increased infiltration rates. LANL provided few data to justify assumptions about the relative immobility of wastes at these sites. Recommendation: LANL should confirm the integrity (lack of surface disturbances or conditions leading to increased infiltration) of the major disposal sites in the dry canyons and mesas. LANL should schedule regular subsurface surveillance beneath disposed wastes on dry mesas and in dry canyons. LANL’s present conceptualizations of the regional aquifer lead to very different pictures of how contaminants in the aquifer might behave. If there is low connectivity between layers within the aquifer, the contaminants might remain near the top of the regional aquifer and most likely discharge in the springs near the Rio Grande. On the other hand, higher connectivity could result in the contaminants spreading vertically and more likely entering the deep screened intervals of regional water supply wells. Recommendation: LANL should continue efforts begun under the Hydrogeologic Workplan to characterize the regional aquifer. More large-scale pumping tests and improved analyses of the drawdown data are needed to establish a scientifically defensible conceptual model of the aquifer, i.e., leaky-confined, unconfined, or layered. LANL’s efforts to understand the role of geochemistry in contaminant migration have not kept pace with efforts to understand hydrology. The committee found a lack of basic, site-specific geochemical data to support LANL’s assumptions about the relative immobility of important contaminants—especially radionuclides—along transport pathways and judged that LANL underestimated the value of both field and laboratory geochemical measurements. Recommendation: LANL should increase its attention to geochemistry within the context of its site characterization work. LANL scientists should conduct more field and laboratory studies to measure basic geochemical parameters such as sorption coefficients with the goal of testing and verifying their conceptualizations of subsurface hydrogeochemical processes. The following finding and recommendations reflect the committee’s evaluation of the Interim Facility-wide Groundwater Monitoring Plan (LANL 2006c), which was requested in the Statement of Task. The Hydrogeologic Workplan has been effective in improving characterization of the site’s hydrogeology. However, the knowledge gained through the workplan does not appear to have been used effectively in the development of the interim monitoring plan. The workplan is mentioned only in the introduction of the interim plan, and rationale for the siting of new wells in the interim plan is not grounded in the scientific understanding of the site evident in the Synthesis Report and other publications such as the Vadose Zone Journal (VZJ, 2005). Recommendations: LANL should demonstrate better use of its current understanding of contaminant transport pathways in the design of its groundwater monitoring program. Tables in the monitoring plan that give the rationale for locating monitoring wells should at least provide a general linkage between the proposed
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Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory: Final Report locations and the site’s hydrology, or a section discussing the relation between well locations and pathway conceptualizations should be added. LANL should take a sitewide approach to monitoring the intermediate and regional aquifers. Furthermore, the interim plan should summarize (e.g., in Section 1.6) the ways in which the information from related studies will be used for updating the plan. The current description of the conceptual models (in Appendix A of the plan) is useful, but it should be improved. First and foremost would be a description of potential pathways, both surface and subsurface, that connect the sources (listed in Appendix A) with the groundwater that is being monitored. LANL should examine the potential for approaches that both optimize the monitoring network and incorporate uncertainty into its design (Minsker, 2003; EPA, 2006). Findings and Recommendations on Monitoring and Data Quality Implementing a monitoring plan involves the practicalities of constructing groundwater wells and analyzing samples from the wells. Any monitoring activity faces a conundrum: If little or no contamination is found, does this mean that there is in fact little or no contamination, or that the monitoring itself is flawed? During this study the committee was presented a good deal of information suggesting that most or all wells into the regional aquifer at LANL (R-wells) are flawed for the purpose of monitoring. The committee did not disagree, but rather found a lack of basic scientific knowledge that could help ensure future success. Evidence about the conditions prevalent around the screens in the compromised wells is indirect—relying on plausible but unproven8 chemical interactions, general literature data, analyses of surrogates, and apparent trends in sampling data that may not be statistically valid. The committee’s statement of task posed two questions regarding the reliability of data produced in LANL’s current monitoring program: Is the laboratory following established scientific practices in assessing the quality of its groundwater monitoring data? Are the data (including qualifiers that describe data precision, accuracy, detection limits, and other items that aid correct interpretation and use of the data) being used appropriately in the laboratory’s remediation decision making? The short answer to the first item is a qualified yes. LANL is using good practices in terms of having the proper quality assurance and quality control (QA/QC) plans and documentation in place, but falls short of consistently carrying out all the procedures cited in the plans. Well drilling and completion methods are continuing to evolve, and the site is only beginning to implement its groundwater monitoring program under the Consent Order. The answer to the second item as written was judged as no. Although LANL appears to be generating sound analytical data, the results presented in databases and LANL reports often do not carry the proper qualifiers according to good QA/QC practices. This especially applies to analytical results near or below the limits of practical quantitation and detection, near the natural background, or both. The difficulty here is that reported detection of contamination that is not statistically significant may be taken as real by regulators and other stakeholders—with concomitant concerns and calls for remedial actions. The following findings and recommendations are intended to strengthen LANL’s well drilling and sample analyses for site monitoring. Data from scientifically vetted (peer-reviewed) studies are necessary to authoritatively address concerns and uncertainties about how drilling and well completion processes might alter the native conditions around well screens and to ensure reliable monitoring activities in the future. The committee received little scientific information—for example, on a par with LANL’s publications about vadose zone pathways (VZJ, 2005)—regarding the geochemical behavior of contaminants in the subsurface or effects of non-native materials (drilling fluids, additives, construction materials) on the geologic media to be sampled. Recommendation: LANL should plan and carry out geochemical research to ascertain the interactive behavior of contaminants, materials introduced in drilling and well completion, and the geologic media. As a part of LANL’s future plans for sitewide monitoring, this work would include: Determining the nature of interactions among materials proposed for use in constructing monitoring wells and the types of geological media that LANL intends to monitor, Quantitative measurement of sorption of contaminants onto the natural, added, and possibly altered constituents that constitute the sampling environment of a monitoring well, and Publication of results in peer-reviewed literature. The committee is not recommending open-ended research. Rather, targeted investigations would underpin plans for future monitoring of specific areas of the site: 8 Not directly observed and measured under LANL site conditions.
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Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory: Final Report contaminants of greatest concern in the area, geologic media expected to be sampled (known from previous site characterization), and drilling fluids, additives, and other materials intended to be used in constructing the monitoring well(s). Screening tests envisioned by the committee would include simple batch equilibrium tests to measure solubilities and sorption coefficients (Kd) and to determine what, if any, interactions actually occur among drilling materials and the geologic media—and whether alterations are permanent or temporary. More detailed column tests can simulate and measure effects of flow rate and surface area (mass transfer) around the well screens. Planning, conducting, and interpreting the results will require the high quality of science one would expect of a national laboratory. LANL’s work under the Hydrogeologic Workplan significantly enhanced understanding of the hydrological characteristics of the site, and lessons learned during the program can improve future drilling efforts. Wells constructed under the Hydrogeologic Workplan were intended for characterization. LANL later attempted to use the characterization wells that reached the regional aquifer for monitoring. As noted earlier, their use for monitoring was evidently compromised by drilling and well development procedures. Recommendation: LANL should plan and conduct future characterization drilling and monitoring well drilling as separate tasks. For monitoring locations where characterization data are unavailable, LANL should consider drilling simple test holes to obtain these data before attempting to drill the monitoring well(s). With the more complete hydrogeologic characterization that is now available (see Chapter 4), LANL can design and construct future monitoring wells more confidently. LANL’s plans to obtain geologic and geophysical logs during drilling further increase confidence that well screens can be installed to intercept a contaminant pathway. Recommendation: LANL should design and install new monitoring wells with the following attributes: A borehole drilled through the monitoring zone without the introduction of drilling muds or additives (i.e., use air or water), One screened interval that targets a single saturated zone, and A carefully planned design (length and depth) of the well screen, which is confirmed with information collected in the drilling process. Drilling under specific conditions and sampling requirements can lead to exceptions to the above, and adapting to circumstances will be necessary. With regard to LANL’s practices in assessing the quality of its groundwater sampling data, the committee found that good data quality procedures are in place, but there is a lack of follow-through in how the data are reported. Recommendation: LANL should ensure that there is consistency and clarity of all related sampling and analytical procedures with documented follow-through and appropriate action. This especially relates to: having clear data quality objectives; documenting how samples are to be collected; documenting how data are handled, statistically compiled, and reported; clear documentation of the quality of the data; and identification of all suspect data. Interpreting data at or near analytical detection limits is an area of growing scientific interest. LANL can benefit from scientific exchanges with other groups and organizations that are actively working in this area (e.g., the Environmental Protection Agency, American Society for Testing and Materials). Lack of agreement between LANL, regulators, and concerned citizens as to what constitutes the appropriate representation of groundwater contamination data is a source of confusion and distrust. Recommendation: LANL should ensure that measurements at or near background levels or near analytical detection limits (i.e., Method Detection Limits and Practical Quantitation Levels) are scientifically and statistically sound and are reported appropriately. The LANL site office of DOE should take steps to ensure that LANL and site regulators agree on how all such data are to be handled, compiled, and reported. LANL should make more effort to ensure that data uncertainties are made clear to public stakeholders. LANL’s Groundwater Background Investigation Report (LANL, 2006b) is an important step in establishing levels of naturally occurring contamination in the regional aquifer, although some data quality gaps were identified by the committee. The Integrated Groundwater Monitoring Plan (LANL, 2006c) lists non-LANL sources of groundwater contamination. Such data are important to support future remediation decision making. Recommendations: LANL should continue to track regional groundwater monitoring wells and water supply wells routinely to improve the statistical basis for reporting any increases above background.
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Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory: Final Report LANL’s Quality Assurance Project Plan should enforce the documentation of any and all instances where it is believed that chemicals or radionuclides detected in groundwater are not the result of LANL operations, e.g., naturally occurring or anthropogenic contaminants or the result of sampling artifacts. CONCLUDING REMARKS LANL’s groundwater protection program is at about its temporal midpoint, continuing for another eight years until 2015. The Consent Order establishes an enforceable process and schedule for the program. The committee hopes that the assessments, findings, and recommendations presented in this report will be useful in informing future technical decisions that will be made within the Consent Order process.
Representative terms from entire chapter: