Environmental Site Assessment Research Articles

Stabilization treatment of contaminated soil: a field-scale application in Shanghai, China

Stabilization is one of the best demonstrated available technologies for treating toxic pollutants in soils and has been used worldwide but is rarely used for treatment of contaminated sites in China despite many bench-scale studies. Here, a field-scale application of stabilization treatment in Shanghai, China was summarized to demonstrate the whole engineering process and the key technical issues regarding stabilization of contaminated soil. A site contaminated with arsenic (As) and polycyclic aromatic hydrocarbons (PAHs), formerly used as a lighting plant in Shanghai, was chosen as the demonstration site. Stabilizing measures were taken to treat the contaminated soil to reuse the site for residential purposes. The whole engineering remediation process consisted of phase I environmental site assessment (ESA) and phase II ESA, quantitative human health risk assessment, remediation alternatives evaluation, bench-scale testing, remedial design, engineering implementation, and post-remediation assessment. A third party conducted evaluation monitoring indicated desirable results were achieved via the stabilization treatment. In addition, some technical obstacles related to soil stabilization treatment were discussed, including soil quality evaluation, stabilization effectiveness validation, and soil reuse assessment.

Environmental Site Assessment of Al-Daura Refinery - Evaluation of Soil Pollution with Petroleum Products

Environmental Site Assessment of Al-Daura Refinery - Evaluation of Soil Pollution with Petroleum Products

Challenges and successes in using inductively coupled plasma mass spectrometry for measurements of tungsten in environmental water and soil samples

Military small arms ranges in the United States have been used for munitions training with tungsten rounds, which are comprised of powdered tungsten (W) pressed together with polymeric binders. As a result, W has been introduced into surface soils. The environmental and human health effects of W remain open questions. The US Army Corps of Engineers is responsible for environmental monitoring, site assessments, and cleanup of small arms ranges. This work requires routine measurements of tungsten in natural waters and soils. However, the existing sample preparation and analytical procedures were not specifically developed with W in mind for environmental analysis. Our work suggests modification of existing metal sample preparation and analytical procedures are necessary to accurately quantify W in environmental media. Our group has been actively conducting W measurements using inductively coupled plasma mass spectrometry (ICPMS), both with quadrupole and sector field ICPMS systems. We have used heavy rare earth elements and iridium as internal standards. For soils, the great majority of the W from small arms can be dissolved using acid leaching with HNO3–H3PO4 mixtures; more rigorous preparations with fusion or HF digestions can also be used. In ICPMS analysis, the largest challenge involves dealing with the significant carry-over and memory of W in sample introduction systems. This ultimately limits measurement capabilities, particularly at sub-µg L−1 levels. With careful attention to the sample and standards’ matrix constituents, and proper washout time, successful analysis is possible and ICPMS is clearly the preferred technique. A commercially available fluoropolymer sample introduction system exhibits significantly improved memory characteristics.

Application of discriminant analysis with clustered data to determine anthropogenic metals contamination

Environmental site assessments involve, among other things, characterization of the nature and extent of contamination. In general, environmental assessors are interested in empirical methodologies that can be applied to a broad range of environmental media (e.g., soils, sediments, etc.) and situations. To date, no unified guidance has been adopted, and site investigations usually involve a tiered process with multiple analyses. We propose a multivariate analysis methodology utilizing discriminant analysis with clustered chemical concentrations as a novel application to environmental site assessments that determine, in relative order of magnitude, contaminated chemicals. Finite mixture models are presented as a means to assess latent chemical clusters with some basis in statistical inference. The methodology is illustrated with a typical localized data set containing total metal and metalloid (i.e., chemical) concentrations, extracted from bulk soil collected from reference and site-related locations, obtained from a former military installation in the southeast United Sates. The illustration is particularly applicable because site-related soils inherently possessed higher background chemical levels than reference soils, which biased conventional analyses. However, contrasting chemical compositions were inferred within site-related samples illustrating the versatility of the proposed methodology. Using these results along with known information regarding the history of contamination at the site, a qualitative and quantitative assessment of contaminated chemicals was made. Results are intended for illustration purposes only and are discussed within the context of environmental site assessment.

Evaluation of geochemical associations as a screening tool for identifying anthropogenic trace metal contamination

Geochemical association plots are used as a screening tool for environmental site assessments and use empirical log-log relationships between total trace metal concentrations and concentrations of a major (i.e., reference) soil metal constituent, such as iron (Fe), to discern sites with naturally elevated trace metal levels from sites with anthropogenic contamination. Log-log relationships have been consistently observed between trace metal and reference metal concentrations and are often considered constant. Consequently, we used a regional geochemistry data set to evaluate background trace metal/Fe log-log associations across soils with highly diverse composition. Our results indicate that, although geochemical associations may be proportional, they significantly differ across predominant United States Department of Agriculture (USDA) soil orders. This suggests that highly complex interactions between soil-forming factors and variable secondary clay mineral composition affect the ratio of trace metals to Fe concentrations in soils. Also, intra-order variability in trace metal/Fe ratios generally ranged multiple orders of magnitude which suggest that the order level of the USDA soil taxonomic system is insufficient to reasonably classify background trace metal concentrations. Consequently, geochemical association plots are a useful screening tool for environmental site assessments, but ubiquitous application of generic background metal data sets could result in erroneous conclusions. Because significantly different ratios were observed across predominant USDA soil orders, an agglomerative clustering technique was used to elucidate hierarchical patterns of association. We present these results as a mechanism to aid environmental assessors in screening candidate background metal data sets for their applicability to site-specific soil composition; although site-specific background metal data should be utilized if ample pristine reference sites with similar (i.e., sub-order) soil composition can be identified and sampled.

Environmental site assessment of an oil field and detection and imaging of sinkholes using a novel geophysical method

Geophysical surveying methods have expanded to address the issues associated with assessing near-surface conditions of oil fields and detection and imaging of sinkholes. Continual high demand for mineral resources to meet the growing need for energy and water have impacted the environment in many visible and not so visible ways. Resource extraction from the Earth usually results in ground subsidence and/or cavities. Over time, subsurface cavities may increase in size due to dissolution or erosion and could migrate upward to the surface.

The environmental manager's guide to environmental liability insurance

Those readers who have spent more It's not your grandfather's than a few years in the environmental insurance-policies have field-and those who count their experi­ changed ence in decadesare aware of how technology, regula­ tions, policies, and practices have evolved to pre­ vent and reduce pollution and clean up both his­ torical and recent contamination. Over the years, regulations and other initiatives have curtailed many of the activities that led to the release of contaminants. Solutions, both government­ driven and founded within the private sector, have arisen to address impacts to human health and the environment. Businesses have adopted many new practices that minimize impact on both the environment and their own bottom lines. In addition to rigor­ ous pollution prevention programs, buying green, product stewardship, ISO 14000 registration, and other initiatives that companies have embraced to address environmental impacts, many businesses have turned to the insurance market. resources damage, business interrup­ tion, and emotional pain and suffering experienced by resi­ dential neighbors who have to evacu­ ate during a chemi­ cal release. What does environmental liability insurance do'? In many cases, it greases the wheels to ensure that businesses can continue to operate and pro­ tect the environment. An environmental liability insurance policy can have a major impact when a merger and acquisition is being planned, a brownfield site is being redeveloped, or a real es­ tate developer wants to purchase property with­ out worrying about shouldering the expense of proving an innocent landowner defense if the Phase I environmental site assessment misses a recognized environmental condition. Environmental liability insurance is one more tool that, when joined with other advances in en­ vironmental technology and management, makes it possible for businesses and-particularly

AAI and the Necessity for an Opinion regarding Additional Investigation as Part of the Performance of an ASTM E1527-05 Phase I Environmental Site Assessment

On November 1, 2005, the U.S. EPA published its final rule pertaining to the Standards and Practices for All Appropriate Inquiries AAI . Shortly thereafter, ASTM published its updated E1527-05 Standard Practice for Environmental Site Assessments: Phase I Environmental Site Assessment Process. Much has been written about the new requirements and latest landowner liability protections LLP’s that evolved as a result of Congress’ actions and the new EPA rule i.e., the addition of the contiguous property owner CPO and bona fide prospective purchaser BFPP defenses to Comprehensive Environmental Response, Compensation, and Liability Act CERCLA liability . There is, however, one aspect of the AAI Rule and revised Standard that remains a source of confusion. It lies within the very last sentence of the AAI Rule, wherein it states: “The inquiry of the environmental professional should include an opinion regarding additional appropriate investigation, if any.” FR Doc. 05-21455, §312.31 b , Page 66113 . This directive is carried through to the new ASTM Standard, wherein it states, in part, “The environmental professional should provide an opinion regarding additional appropriate investigation, if any, to detect the presence of hazardous substances or petroleum products” ASTM Section 12.6.1 . The problem is that this language has been interpreted by many within the industry as guidance that directs that recommendations regarding the collection of new data through, for example, sampling and analysis, are now appropriate even mandated as part of the completion of a Phase I Environmental Site Assessment ESA . Such interpretation is misguided, and will have a profound impact on the commercial real estate industry, if not clarified. The position here is that if EPA intended to do away with the finality of a Phase I ESA except where recognized environmental conditions REC’s are identified in the context of specific uncertainties and mandated the collection of new data such as that associated with sampling and analysis, it could have chosen to do so but did not, as Section X of the Preamble language to the EPA Rule itself proclaims. First and foremost, the CERCLA a.k.a., Superfund, through its 1986 amendments, already included a provision that in order to qualify for the so-called “innocent landowner defense” to CERCLA, a subset of the CERCLA third party defense presented within 42 U.S.C. §9607 b 3 , one must satisfy a number of criteria, including: “the degree of obviousness of the presence or likely presence of contamination at the property, and the ability to detect the contamination by appropriate investigation” CERCLA §312.31 . Thus, we are not charting new ground here. The requirement to conduct appropriate investigation has always been a

Passive solar design of mass housing: Ensuring environmental improvements at the planning stage for suburban housing

The development of an Environmental Site Assessment tool is described which is designed to be used by planners and developers of speculative housing, for the appraisal of whole new housing developments. The aim of the tool is to establish the implications of trade-offs between passive solar designs and more conventional suburban housing, while achieving a particular site density target. The tool can determine what the effect of changing housing density will have upon a passive solar development. The whole life financial and environmental costs are then calculated accordingly for a housing project. Although the research has involved detailed analysis of building performance, the focus of the tool is on the footprint of the house and the early stage design of housing layouts. Thus, it can have an influence on passive solar performance from the earliest part of the planning process, even before the sketch design stage. The intention, with further development of the tool, is to provide a comparative analysis between dominant current approaches and emerging environmental methods of construction in housing developments. At this stage, the tool is a prototype which aims to simplify a focused range of complex planning issues to give an informed and best case scenario of anticipated costs and emissions over the lifecycle of housing developments. Although this tool is aimed at smoothing the adoption of more sustainable housing practice during the planning stage, by providing discourse between local authority planners and the builders of housing developments, ultimately the main aim is to benefit the environment by reducing emissions and the homebuyer by reducing household energy costs and increasing comfort.

Amplified geochemical imaging: an enhanced view to optimize outcomes

Harry S. Anderson of W. L. Gore & Associates describes the benefits of amplified geochemical imaging in a variety of context including environmental and oil and gas applications. Before surgeons begin any delicate operation, they use state-of–the-art imaging to afford an enhanced view into the human body. Without question, the accuracy and detail of a CAT scan or MRI increases their chance of a successful surgical outcome. With a resource so precious, who wouldn’t use the best technology? Likewise today’s earth scientists have sophisticated imaging tools available that provide them with the enhanced view they need to focus their efforts, save time and money, and generate more reserves and profits. 3D seismic imaging is the tool we often think of first in petroleum exploration but recent advances have made possible a complementary technique: amplified geochemical imaging. This advanced geoscience tool is used in diverse applications such as environmental site assessment and pipeline integrity management, as well as petroleum and mineral exploration. Since 1930, earth scientists have used surface geochemical techniques to explore for hydrocarbons. These techniques look for the effects of minute levels of hydrocarbons that migrate through the imperfect seals that cover every reservoir and migrate either as macroseepage via faults or as microseepage vertically through the reservoir overburden. (Klusman, 1993, Coleman et al., 1977) Some of these early techniques were crude and included soil analysis, active soil gas analysis, iodine mapping, and microbial counting. Unfortunately, exploration results using these early geochemical techniques were often disappointing. This is a direct result of several fundamental factors: - Inability of the sampling method to cope with heterogeneous soil characteristics including permeability, moisture, and organic content - Heavy losses in compounds due to sampling techniques (Hewitt and Lukash, 1996) - Monitoring indirect effects (like microbes or iodine) rather than direct effects - Poor sensitivity (ppm rather than ppb or ppt) - Severely limited set of compounds not representative of the target (C1-C6 only) - Failure to use statistical tools to clearly differentiate noise from signal

Perspective: Licensing for Environmental Assessment Professionals: The Time Has Come

Conditions in today's environmental site assessment industry dictate the necessity of a new type of licensing program designed to cover environmental professionals originating from a wide variety o...

Environmental hazards posed by the Los Angeles Basin urban oilfields: an historical perspective of lessons learned

Urban encroachment into areas historically reserved for oil and gas field operations is an ever-present problem within the Los Angeles Basin. The recent frenzy in real estate development has only intensified what can be characterized as a conflict in land usage. Subsurface mineral rights are severed from surface ownership, often resulting in developments being approved without adequate consideration of the underlying oil and gas field consequences. Also, surface operations are frequently co-located within residential areas without consideration of the health and safety consequences of emissions of toxics to air. This paper presents a review of the environmental, health and safety hazards posed by urban oilfield operations, with an emphasis upon the lessons learned from the “L.A. Basin: Original Urban Oilfield Legend” (see Castle and Yerkes 1976; Denton and others 2001; Endres and others 2002; Kouznetsov and others 1994; Katz and others 1994; Schumacher and Abrams 1994; and Schoell 1983). The Los Angeles Basin has provided the authors with one of the largest natural laboratories in the world for studying the consequences of these issues. The results presented are part of a long-term research program based upon the application of geoscience and petroleum engineering principles in obtaining a fundamental understanding of the root causes of the environmental hazards posed. Topics addressed include: (1) vertical migration of gas to the surface along faults and improperly completed or abandoned wellbores (e.g., due to poor cementing practices), (2) subsidence caused by the fluid production and declining reservoir pressures, (3) soil and groundwater contamination resulting from historic oil and gas field operations, and (4) air toxics resulting from surface operations. A number of case histories are discussed that illustrate the seriousness of the problem. A clear case is made for the urgent need for closer coordination and education by the petroleum industry of the local government planning departments. These departments have the principal role in determining land use policies, acting as the lead agency in performing environmental site assessments (e.g., under the California Environmental Quality Act), and in establishing mitigation measures for dealing with the long-term environmental hazards. This paper establishes prudent practices on the part of oilfield operators for the monitoring and mitigation of these hazards.

Due diligence and environmental site assessments: Impact of EPA's Upcoming “all appropriate inquiry” rule

Environmental Quality ManagementVolume 13, Issue 4 p. 59-69 Feature Due diligence and environmental site assessments: Impact of EPA's Upcoming “all appropriate inquiry” rule Kristen M. Graziano, Kristen M. Graziano Environmental Strategies Consulting, LLC, Reston, VirginiaSearch for more papers by this author Kristen M. Graziano, Kristen M. Graziano Environmental Strategies Consulting, LLC, Reston, VirginiaSearch for more papers by this author First published: 18 June 2004 https://doi.org/10.1002/tqem.20016AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume13, Issue4Summer 2004Pages 59-69 RelatedInformation

Imaging spectroscopy: Earth and planetary remote sensing with the USGS Tetracorder and expert systems

Imaging spectroscopy is a tool that can be used to spectrally identify and spatially map materials based on their specific chemical bonds. Spectroscopic analysis requires significantly more sophistication than has been employed in conventional broadband remote sensing analysis. We describe a new system that is effective at material identification and mapping: a set of algorithms within an expert system decision‐making framework that we call Tetracorder. The expertise in the system has been derived from scientific knowledge of spectral identification. The expert system rules are implemented in a decision tree where multiple algorithms are applied to spectral analysis, additional expert rules and algorithms can be applied based on initial results, and more decisions are made until spectral analysis is complete. Because certain spectral features are indicative of specific chemical bonds in materials, the system can accurately identify and map those materials. In this paper we describe the framework of the decision making process used for spectral identification, describe specific spectral feature analysis algorithms, and give examples of what analyses and types of maps are possible with imaging spectroscopy data. We also present the expert system rules that describe which diagnostic spectral features are used in the decision making process for a set of spectra of minerals and other common materials. We demonstrate the applications of Tetracorder to identify and map surface minerals, to detect sources of acid rock drainage, and to map vegetation species, ice, melting snow, water, and water pollution, all with one set of expert system rules. Mineral mapping can aid in geologic mapping and fault detection and can provide a better understanding of weathering, mineralization, hydrothermal alteration, and other geologic processes. Environmental site assessment, such as mapping source areas of acid mine drainage, has resulted in the acceleration of site cleanup, saving millions of dollars and years in cleanup time. Imaging spectroscopy data and Tetracorder analysis can be used to study both terrestrial and planetary science problems. Imaging spectroscopy can be used to probe planetary systems, including their atmospheres, oceans, and land surfaces.

Making Geology Relevant to Non-Science Majors Through the Environmental Site Assessment Project

The Environmental Site Assessment (ESA) project was developed to make geology more relevant to the non-science majors in Appalachian State University's Environmental and Applied Geology course. Pedagogically, this exercise is an example of directed-inquiry. Students are guided in applying the geoscience theory learned in the formal classroom setting to the reality of their own independent research projects. Through participation in the ESA project, students investigate earth resource issues of water quality and water supply, and geologic hazards specific to each student's place of residence. Student survey results indicated that this project had a positive impact on students' perceptions of the value and relevance of geoscience, particularly that knowledge gained from the ESA project would be very helpful to them in future decision-making situations, such as home or business site selection. With little modification, this exercise is transferable to survey geology courses at other colleges and to middle and high school earth and environmental science programs.

The complete book of pesticide management: science, regulation, stewardship, and communication

Contributors. Preface. Introduction. The Evolution of Pesticide Regulations: The Shift From Benefits to Risks (F. Whitford, et al.). Human Health Risk Assessment: Evaluating Potential Effects of Pesticides on Humans (F. Whitford, et al.). Epidemiology: Validating Human Risk Assessments (F. Whitford, et al.). Ecological Risk Assessments: Evaluating Pesticide Risks to Nontarget Species (F. Whitford, et al.). Water Quality Risk Assessment: Predicting Complex Interactions Between Pesticides and the Environment (F. Whitford, et al.). Product Development and Registration: Blending Scientific Information into Public Policy Decisions (F. Whitford, et al.). Pesticide Lables: The Convergence of Science, Public Policy, and User Responsibility (F. Whitford, et al.). Liabilities and Lawsuits: Understanding Regulations, Inspections, and the Courts (F. Whitford, et al.). Environmental Site Assessments: Managing the Facility Against Contamination (F. Whitford, et al.). Occupational Use of Pesticides: Handling Products in the Workplace (F. Whitford, et al.). Personal Protective Equipment: Selection, Care, and Use (F. Whitford, et al.). The Employee Bulletin Board: Where Employers Communicate Policies, Procedures, and Practices to Employees (F. Whitford, et al.). Planning for Emergencies: Preventing and Reacting to Emergencies in the Workplace (F. Whitford, et al.). The Insurance Policy: Protecting Yourself Against the Unexpected (F. Whitford, et al.). Educating the Community and the Workforce About Hazardous Chemicals (F. Whitford, et al.). Educating Your Consumer Clientele: A Holistic Approach to Pest Management (F. Whitford, et al.). Risk Communication: Interactions and Dialogues with the Public (F. Whitford, et al.). Today s Discussions, Tomorrow s Issues (F. Whitford, et al.). Conclusion. Index.

Beyond Phase I Environmental Site Assessments-conducting Business Environmental Risk Assessments Of Oil Field Acquisitions

Environmental due diligence investigations for proposed oil field acquisitions are typically conducted for two different purposes. In the first case, an oil company desires to purchase an oil field to conduct on-going crude oil and natural gas production operation. In the second case, the owner of the property (an oil company) desires to sell an existing oil field operation to a real estate developer for residential, commercial, or industrial redevelopment. The American Society of Testing Materials (ASTM) has developed a standard practice for conducting Phase I Environmental Site Assessments (Phase I Assessment) associated with the transfer of commercial property (E-1527-97). The primary objectives of the ASTM standard practice is to identify apparent conditions of environmental concern and conduct adequate due diligence so that the buyer can avail himself of the “innocent purchaser provision” under Comprehensive Emergency Response, Compensation, and Liability Act (CERCLA). These objectives have limited relevance for most acquisitions of oil field properties. Most oil field properties have environmental impairments. The threshold questions relate to the allocation of risk for current and future liabilities between the buyer and seller. There is a petroleum products exclusion under CERCLA. An Environmental Business Risk Assessment goes beyond the traditional Phase I Assessment to better meet the business needs of purchasers of oil field properties. The scope of the Environmental Business Risk Assessment is tailored to the level of sophistication and the risk tolerance of the buyer and the nature of the deal. Buyers of oil field properties can range from oil companies with environmental staffs to real estate developers who have limited knowledge of oil field operations. Sophisticated buyers may only need assistance identifying “exception” issues and estimates of the most likely cost and worst case scenario costs associated with these identified current and future liabilities. These buyers can generally estimate future well abandonment and facility demolition costs in-house. These buyers may also be able to estimate in-house remediation costs associated with shallow crude oil–impacted soil and other conditions typical of oil field operations. Less sophisticated buyers may need more assistance in these areas. For buyers interested in redevelopment of oil fields, the threshold question is can the site be prepared for redevelopment at a low enough cost in order that the developer can make a desired rate of return on their investment. One way to address this issue is through a focused Phase I/Phase II Assessment conducted in stages. The primary objective of Phase I is to gather just enough information to select locations for the focused Phase II investigation. The objective of the first stage of the Phase II Investigation is to confirm the general nature and extent of environmental impairments to ascertain whether it makes sense to continue. In some cases, this initial investigation will suggest that the cost of site remediation will exceed an economic threshold that makes redevelopment of the site unattractive. If the initial Phase II Assessment work is favorable, additional work is conducted consistent with the level of business risk and uncertainty the developer is willing to accept. Historically, oil field sellers have provided either a full or partial indemnification to the buyer for environmental conditions that existed before the date of sale or have provided a due diligence period after the date of sale for the buyer to conduct additional environmental investigations. In the later case, the buyer could make claims against the seller for environmental conditions that were discovered that had a liability above a certain dollar amount as a post-closing adjustment to the purchase price. These types of deals are less common today. More typical today is an “as-is” sale where the seller is willing to entertain adjustments in the purchase price for environmental impairments identified by the buyer in a due diligence period before closing. The Environmental Business Risk Assessment provides information the buyer needs to make informed business decisions about allocation of risk as a part of the negotiation of the Purchase and Sales Agreement.

Phase I Environmental Site Assessment

Phase I Environmental Site Assessment

ICBMs and the Environment: Assessments at a Base in Kazakhstan

A paper by two U.S. scientists explores the environmental/health hazard posed by abandoned missile launch sites and control facilities (dismantled by 1998 as part of the Nunn-Lugar Cooperative Threat Reduction Program) at an ICBM base in north-central Kazakhstan. It summarizes the findings of Environmental Site Assessment Reports based on a program of water and soil sampling at the sites, with a particular focus on testing for the presence of polychlorinated biphenyls, various toxic metals, and radiation. The study is important in that it documents levels of contamination (and describes abatement measures) at a former Soviet missile base. Journal of Economic Literature, Classification Numbers: H50, 110, Q20, 7 figures, 10 references.

Environmental Site Characterization and Risk-Based Evaluation of a Site Contaminated with Tetrachloroethene (PCE) and Trichloroethene (TCE)

A healthcare company purchased property in eastern Iowa for a facility expansion. Before the purchase, a Phase I environmental site assessment (ESA) revealed that the property was the site of a former dry cleaning business. Phase II sampling and testing indicated that tetrachloroethene (PCE) and trichloroethene (TCE) had affected site soil and groundwater. Maximum concentrations of PCE and TCE in groundwater were 538 and 209 μg/L, respectively, and 105 and 1.51 mg/kg in soil. Additional sampling delineated the vertical and horizontal extent of contamination in the soil. The concentrations of the chlorinated solvents in both the soil and groundwater were below levels of regulatory concern. However, the company was concerned that the Iowa statewide standard for PCE in soil (780 mg/kg) might not provide adequate protection for several exposure pathways and wanted to assess the risk to the public from the contamination at the site. The results of a receptor survey were used to develop site-specific target levels (SSTLs) for contamination, using accepted human health exposure factors, models, and chemical-specific toxicity values. The recommended remedial options allowed the company to minimize the human health risks posed by contamination at the site. ABSTRACT