Risk-based Decision Process for Arsenic in Soils: Implications of Conservative Protocols

Making defensible risk-based decisions is a complex process that incorporates risk assessment into a risk management framework. Many site investigations require additional study, negotiations and/or actions for arsenic detected in soil samples, in many cases where no process related sources are identified and no other chemicals of concern are identified. Regulatory agencies develop guidance to standardize approaches to risk-based site investigations that focus on achieving “safe” concentrations. For arsenic, the action level is frequently in the “gray region”, a U.S. Environmental Protection Agency (USEPA) term associated with a region of high uncertainty for risk management decisions in the “decision performance curve” associated with the data quality objective (DQO) process. Recognizing the conservative nature of the risk-based screening value for arsenic, approaches to enforce this level (or proof of comparability to natural background) may have numerous consequences including ineffective use of resources, stigmas on properties or actions at industrial or hazardous sites that are inconsistent with their regional setting. Florida has developed regulations and guidance on investigation of brownfield sites and has supported a study by the University of Florida (UF) to evaluate natural background concentrations in Florida soils. This paper discusses the sources of uncertainty near the soil cleanup target levels (SCTLs) in the Florida decision-making framework.     

Risk-based Decision Process for Arsenic in Soils: Implications of Conservative Protocols

Making defensible risk-based decisions is a complex process that incorporates risk assessment into a risk management framework. Many site investigations require additional study, negotiations and/or actions for arsenic detected in soil samples, in many cases where no process related sources are identified and no other chemicals of concern are identified. Regulatory agencies develop guidance to standardize approaches to risk-based site investigations that focus on achieving "safe" concentrations. For arsenic, the action level is frequently in the "gray region", a U.S. Environmental Protection Agency (USEPA) term associated with a region of high uncertainty for risk management decisions in the "decision performance curve" associated with the data quality objective (DQO) process. Recognizing the conservative nature of the risk-based screening value for arsenic, approaches to enforce this level (or proof of comparability to natural background) may have numerous consequences including ineffective use of resources, stigmas on properties or actions at industrial or hazardous sites that are inconsistent with their regional setting. Florida has developed regulations and guidance on investigation of brownfield sites and has supported a study by the University of Florida (UF) to evaluate natural background concentrations in Florida soils. This paper discusses the sources of uncertainty near the soil cleanup target levels (SCTLs) in the Florida decision-making framework.     

A Strategy and Methodology for Defensibly Correlating Spilled Oil to Source Candidates

The source of crude oils and petroleum products released into navigable waterways and shipping lanes is not always known. Thus, the defensible identification of spilled crude oils and petroleum products and their correlation to suspected sources is a critical part of many oil spill assessments. Quantitative "fingerprinting" analysis, when evaluated using straightforward statistical and numerical analyses, provides a defensible means to differentiate among qualitatively similar oils and provides the best assessment of the source(s) for spilled oils. Polycyclic aromatic hydrocarbon (PAH) and petroleum biomarker concentration data are a particularly useful quantitative measure that can benefit most oil spill investigations. In this paper the strategy and methodology for correlation analysis that relies upon quantitative gas chromatography/mass spectrometry operated in the selected ion monitoring mode (GC/MS-SIM) is demonstrated in a case study involving 66 candidate sources for a heavy fuel oil spill of unknown origin. The strategy includes identification of 19 chemical indices (out of 45 evaluated) based upon PAH's and biomarkers that were (1) independent of weathering; and (2) precisely measured, both of which are determined by statistical analysis of the data. The 19 chemical indices meeting these criteria are subsequently analysed using principal component analysis (PCA), which helps to determine defensibly the "prime suspects" for the oil spill under investigation. The strategy and methodology described, which combines statistical and numerical analysis of quantitative chemical data, can be adapted and applied to other environmental forensic investigations with the objective of correlating any form of contamination to its suspected sources.     

A Strategy and Methodology for Defensibly Correlating Spilled Oil to Source Candidates

The source of crude oils and petroleum products released into navigable waterways and shipping lanes is not always known. Thus, the defensible identification of spilled crude oils and petroleum products and their correlation to suspected sources is a critical part of many oil spill assessments. Quantitative “fingerprinting” analysis, when evaluated using straightforward statistical and numerical analyses, provides a defensible means to differentiate among qualitatively similar oils and provides the best assessment of the source(s) for spilled oils. Polycyclic aromatic hydrocarbon (PAH) and petroleum biomarker concentration data are a particularly useful quantitative measure that can benefit most oil spill investigations. In this paper the strategy and methodology for correlation analysis that relies upon quantitative gas chromatography/mass spectrometry operated in the selected ion monitoring mode (GC/MS-SIM) is demonstrated in a case study involving 66 candidate sources for a heavy fuel oil spill of unknown origin. The strategy includes identification of 19 chemical indices (out of 45 evaluated) based upon PAH's and biomarkers that were (1) independent of weathering; and (2) precisely measured, both of which are determined by statistical analysis of the data. The 19 chemical indices meeting these criteria are subsequently analysed using principal component analysis (PCA), which helps to determine defensibly the “prime suspects” for the oil spill under investigation. The strategy and methodology described, which combines statistical and numerical analysis of quantitative chemical data, can be adapted and applied to other environmental forensic investigations with the objective of correlating any form of contamination to its suspected sources.     

Recognizing local people's priorities for tropical forest biodiversity

Tropical forest people often suffer from the same processes that threaten biodiversity. An improved knowledge of what is important to local people could improve decision making. This article examines the usefulness of explicitly asking what is important to local people. Our examples draw on biodiversity surveys in East Kalimantan (Indonesian Borneo). With local communities we characterized locally valued habitats, species, and sites, and their significance. This process clarified various priorities and threats, suggested refinements and limits to management options, and indicated issues requiring specific actions, further investigation, or both. It also shows how biological evaluations are more efficient with local guidance, and reveals potential for collaborations between local communities and those concerned with conservation. Such evaluations are a first step in facilitating the incorporation of local concerns into higher-level decision making. Conservationists who engage with local views can benefit from an expanded constituency, and from new opportunities for pursuing effective conservation.     

Cost-benefit analysis as a tool for decision making in environmental projects

BACKGROUND, AIM AND SCOPE: The Damage-Function method is an efficient tool recently used in decision-making processes concerning environmental management. It is based on finding the relation between the origin of an environmental charge, and its impact on human health and the environment. The aim of the present investigation was to assess the positive impacts, also called benefits, of changes in environmental quality, and the economic viability of an industrial project on reduction of PCDD/F emissions. It has been developed with monetary criteria of two worldwide ambits: USA and European-Union countries. METHODS: The current study is a continuation of a previous investigation in which Substance Flow Analysis and Control Analysis Techniques were used to identify and to analyze all main flow values of PCDD/Fs inside the system of Tarragona Province (Spain). In the present study, Cost-Benefit Analysis (CBA) has been employed. The benefits derived from a minimization in the incidence of cancer due to a reduction in the emission of PCDD/Fs have been evaluated considering the value of a statistically saved life (VSL). Statistical analysis about uncertainty has also been incorporated. Here, the Monte Carlo simulation technique has been used. RESULTS: It is shown that CBS results depend firstly on the kind of VSL used. In fact, the differences between the decisions as a result of applying monetary criteria in USA and EU can be explained by differences between VSL values. CONCLUSION AND RECOMMENDATION: It is concluded that, for prices estimated in Euros, the emission cleaning project in the industrial plant is not feasible under any circumstance. However, although CBA seems to be a good analytical method, the final decision corresponds to the managers, who must weigh up not only the monetary criteria, but factors such as social questions.     

Using decision paths to explore three environmental cleanup decisions: a cross-case analysis

Transparent decisions are widely sought by parties interested in and affected by cleanup activities at government-owned facilities. In an approach to transparency, this paper uses decision paths and timelines to compare three decisions at the US Department of Energy Hanford site. A regulatory decision strategy, consisting of seven sequential (linear) steps, is used as the basis for the analysis. We find that the decision path is different for each case, although the timeframe associated with the main steps is similar. Also, although decision steps are evident in each case study, the decision process unfolds in cycles rather than following the linear path typically described to stakeholders. Finally, we observe a stronger emphasis on the information-gathering step than on other steps in the decision process. These findings suggest that new ways of representing decision situations are needed if transparency is to be achieved.     

An environmental decision framework applied to marine engine control technologies

This paper develops a decision framework for considering emission control technologies on marine engines, informed by standard decision theory, with an open structure that may be adapted by operators with specific vessel and technology attributes different from those provided here. Attributes relate objectives important to choosing control technologies with specific alternatives that may meet several of the objectives differently. The transparent framework enables multiple stakeholders to understand how different subjective judgments and varying attribute properties may result in different technology choices. Standard scoring techniques ensure that attributes are not biased by subjective scoring and that weights are the primary quantitative input where subjective preferences are exercised. An expected value decision structure is adopted that considers probabilities (likelihood) that a given alternative can meet its claims; alternative decision criteria are discussed. Capital and annual costs are combined using a net present value approach. An iterative approach is advocated that allows for screening and disqualifying alternatives that do not meet minimum conditions for acceptance, such as engine warranty or U.S. Coast Guard requirements. This decision framework assists vessel operators in considering explicitly important attributes and in representing choices clearly to other stakeholders concerned about reducing air pollution from vessels. This general decision structure may also be applied similarly to other environmental controls in marine applications.     

Policy and Science Implications of the Framing and Qualities of Uncertainty in Risks: Toxic and Beneficial Fish from the Baltic Sea

Policy and research issues in the framing and qualities of uncertainties in risks are analyzed, based on the assessments of dioxin-like compounds (DLCs) and other ingredients in Baltic Sea fish, a high-profile case of governance. Risks are framed broadly, to then focus on dioxins and beneficial fatty acids, fish consumption, human health, and science-management links. Hierarchies of uncertainty (data, model, decision rule, and epistemic) and ambiguity (of values) are used to identify issues of scientific and policy contestation and opportunities for resolving them. The associated complexity of risks is illustrated by risk–benefit analyses of fish consumption and by evaluations of guideline values, highlighting value contents and policy factors in presumably scientific decision criteria, and arguments used in multi-dimensional risk and benefit comparisons. These comparisons pose challenges to narrow assessments centered, for e.g., on toxicants or on food benefits, and to more many-sided and balanced risk communication and management. It is shown that structured and contextualized treatment of uncertainties and ambiguities in a reflexive approach can inform balances between wide and narrow focus, detail and generality, and evidence and precaution.     

Multi-stage optimal design for groundwater remediation: A hybrid bi-level programming approach

This paper presents the development of a hybrid bi-level programming approach for supporting multi-stage groundwater remediation design. To investigate remediation performances, a subsurface model was employed to simulate contaminant transport. A mixed-integer nonlinear optimization model was formulated in order to evaluate different remediation strategies. Multivariate relationships based on a filtered stepwise clustering analysis were developed to facilitate the incorporation of a simulation model within a nonlinear optimization framework. By using the developed statistical relationships, predictions needed for calculating the objective function value can be quickly obtained during the search process. The main advantage of the developed approach is that the remediation strategy can be adjusted from stage to stage, which makes the optimization more realistic. The proposed approach was examined through its application to a real-world aquifer remediation case in western Canada. The optimization results based on this application can help the decision makers to comprehensively evaluate remediation performance.     

国家级流域水环境保护总体规划一般模式研究

流域综合水管理是发达国家普遍采用的管理模式,主要手段之一是制定流域水环境保护总体规划.流域水环境保护总体规划是流域各相关利益方就流域社会经济发展与水环境保护达成的决策,是其他所有规划制定的基础和依据,核心内容是规划目标的确定.流域水环境保护总体规划是流域综合管理的决策平台和信息共享平台,是环境保护的刚性约束,为流域水资源开发利用划定红线.流域水环境保护总体规划是目标导向型的,通过指标体系指导省级行政区负责制定的小流域水环境保护规划,协调流域内省级行政区国民经济和社会发展规划、土地利用总体规划、城市总体规划等其他部门规划.中国目前缺乏流域水环境保护总体规划,基于此提出了国家级流域水环境保护总体规划的一般模式,包括基本内容、规划文本和规划实施3个部分.流域水环境保护总体规划实施的主要手段是审批小流域水环境保护规划.     

Through-electromigration: a new method of investigating pore connectivity and obtaining formation factors

The retardation of radionuclides and other contaminants in fractured crystalline rock is strongly associated with the diffusive properties of the rock matrix. At present, the scientific community is divided concerning the question of long-range pore connectivity in intrusive igneous rock. This paper presents a fast new method, called the through-electromigration method, of obtaining formation factors and investigating pore connectivity. The method involves the migration of an ionic tracer through a rock sample with an electrical potential gradient as the main driving force. The method is analogous to the through-diffusion method but the experimental time is reduced by orders of magnitude. This enables investigations of pore connectivity, as measurements can be made on longer samples. In a preliminary investigation, the new method is compared to the traditional through-diffusion method as well as to rock resistivity methods. The diffusive properties of nine granitic rock samples from Laxemar in Sweden, ranging from 15 to 121 mm in length, have been investigated and the results are compared.     

Confirmation of polychlorinated biphenyl (PCB) distribution in the blood and verification of simple quantitative method for PCBs based on specific congeners

We measured the concentration of each polychlorinated biphenyl (PCB) congener in whole blood, plasma and blood cells, and investigated the distribution of PCBs in human blood using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). The PCB concentrations in plasma and whole blood in terms of lipid concentrations were almost equal, with a correlation coefficient of r = 0.972. In the blood, the ratio of PCBs in blood cells to those in plasma was generally about 1:9 and the congener distribution patterns in blood cells and plasma were similar.We performed verification of a simple mass screening method by obtaining information on the main PCB congeners for investigations on human accumulation and exposure. The total concentration of the seven PCB congeners (UNEP-7) proposed to the United Nations Environment Programme (UNEP) by Muir and Morita was about 50% of the total concentration of all PCB congeners, and UNEP-30 was about 80%. The seven main congeners in the blood (MCB-7) showed a value that was about 60%, and MCB-30 showed a value that was about 90%. Determinations with the main congeners in the blood showed a correlation of r = 0.990 or more between the main eight congeners (MCB-7 plus #74) and the total PCB concentration for all congeners. The results suggest that, although total PCB concentration can be effectively estimated from the main seven congeners, the main eight congeners would be preferable, and that the use of these congeners in the simple mass screening method would be effective for populations in areas uncontaminated by PCBs.     

Parametrization of groundwater quality of the Quaternary aquifer in N’Djamena (Chad), Lake Chad Basin: application of numerical and multivariate analyses

The urban groundwater of the Quaternary aquifer of the Lake Chad basin in N’Djamena has been subject to many hydrochemical studies. However, the results are often not presented in a way that enables water quality managers to make an appropriate decisions, which restrict development and poverty reduction efforts. The objective of the present study was to contribute the improved management of the local groundwater resources. A total of 85 groundwater samples were interpreted using hydrochemical techniques associated with integrated numerical indices and multivariate statistical analysis. The hydrochemical results coupled with the relative residence time of water have shown that the chemical composition of these waters is linked to geogenic and anthropogenic factors and to their proximity to the Chari-Logone rivers. These investigations showed that the groundwater quality in N’Djamena is characterized by a high spatial variability. This study also assessed the suitability of groundwater for user needs and identified areas which are more/less favorable for a specific use. The evaluation of water quality and its suitability for human consumption is also a problem of optimizing data acquisition strategy, and this study used the correlation between water quality index (WQI) and electrical conductivity (EC) to orientate future data acquisition strategies. This parametrization can assist the decision makers and water management professionals in evaluating groundwater availability and setting up a robust water quality management plan in areas with similar hydrogeological and climatic conditions.

     

The influence on partial order ranking from input parameter uncertainty. Definition of a robustness parameter

The method of partial order ranking has been used within the environmental area for a variety of purposes as an attractive way of handling complex information. However, the environmental data are often associated with a significant degree of uncertainty. In this investigation the general nature of the influence from data uncertainty on the partial order ranking is analyzed. A Monte Carlo type analysis is performed in which a series of randomly formed data are used to test the influence of data uncertainty. The partial order ranking is interpreted, where the results are transferred to a one-dimensional ranking scale taking into account that not all elements are ranked with the same certainty. A simple general robustness parameter (E) in form of the expected number of comparisons for each ranking element is defined and correlated to the uncertainty analysis results. A simple equation relates E to the number of elements and the number of parameters, respectively. The magnitude of the ranking uncertainty is shown to increase rapidly when the E value decreases below 4-5 comparisons per element. When the E value exceeds 5 the ranking uncertainty becomes nearly constant and independent on the actual E value.     

Ecosystems,Ecological Restoration,and Economics: Does Habitat or Resource Equivalency Analysis Mean Other Economic Valuation Methods Are Not Needed?

Coastal and other area resources such as tidal wetlands, seagrasses, coral reefs, wetlands, and other ecosystems are often harmed by environmental damage that might be inflicted by human actions, or could occur from natural hazards such as hurricanes. Society may wish to restore resources to offset the harm, or receive compensation if this is not possible, but faces difficult choices among potential compensation projects. The optimal amount of restoration efforts can be determined by non-market valuation methods, service-to-service, or resource-to-resource approaches such as habitat equivalency analysis (HEA). HEA scales injured resources and lost services on a one-to-one trade-off basis. Here, we present the main differences between the HEA approach and other non-market valuation approaches. Particular focus is on the role of the social discount rate, which appears in the HEA equation and underlies calculations of the present value of future damages. We argue that while HEA involves elements of economic analysis, the assumption of a one-to-one trade-off between lost and restored services sometimes does not hold, and then other non-market economic valuation approaches may help in restoration scaling or in damage determination.     

What Price Air Quality the Cost of New Jersey’s Inspection/Maintenance Program

Selection of acceptable sites for industrial facilities, especially hazardous waste management facilities, can be made using a relatively new technique referred to as “fuzzy set analysis.” The methodology presented is applicable to multiple alternative decision making, when criteria are of unequal importance, and is based on the concept of establishing a subjective value for each alternative according to each criterion, and then raising the subjective value to a power commensurate with the relative importance of the criterion. This exponential weight is calculated on the basis of a preferential analysis of criteria comparisons. Apart from the ranking of the alternatives, fuzzy set analysis provides a quantitative representation of the community opinion of the order of importance of the criteria, regardless of the sites being considered. Based on the importance factors averaged from a cross section of the community, public concern could also be ranked.     

Is adaptive management helping to solve fisheries problems?

Adaptive management has been widely recommended as a way to deal with extreme uncertainty in natural resource and environmental decision making. The core concept in adaptive management is that policy choices should be treated as deliberate, large-scale experiments; hence, policy choice should be treated at least partly as a problem of scientific experimental design. There have now been upwards of 100 case studies where attempts were made to apply adaptive management to issues ranging from restoration of endangered desert fish species to protection of the Great Barrier Reef. Most of these cases have been failures in the sense that no experimental management program was ever implemented, and there have been serious problems with monitoring programs in the handful of cases where an experimental plan was implemented. Most of the failures can be traced to three main institutional problems: i) lack of management resources for the expanded monitoring needed to carry out large-scale experiments; ii) unwillingness by decision makers to admit and embrace uncertainty in making policy choices; and iii) lack of leadership in the form of individuals willing to do all the hard work needed to plan and implement new and complex management programs.