重金属污染场地风险评估与治理技术体系研究

在对发达国家污染场地风险评估与治理修复技术方法进行分析的基础上,针对我国重金属污染场地的实际特点,通过调查、分析、实践、优化等方式,对风险评估与治理修复技术开展了系统研究,对风险评估技术在我国的实际应用以及治理修复技术体系的构建提出了模型优化、技术路线优化等相关建议,提出了以浸出浓度为基础依据初步构建重金属污染场地理修复技术体系,并针对治理修复技术的国内产业化分析了技术标准、技术开发应用、市场引导、政府监管等关键影响因素。     

南太湖地区湖州市大气PM_(2.5)中多环芳烃的研究——污染现状和人体暴露健康风险评价

运用智能综合大气采样仪采集了南太湖地区湖州市大气PM 10和PM 2.5样品,采用高效液相色谱检测了该样品中16种多环芳烃化合物,通过苯并(a)芘(Ba P)致癌等效浓度、人群终身超额致癌风险和预期寿命损失等指标,评价湖州市大气PM2.5中多环芳烃的人群健康风险。结果表明:全市大气PM 2.5中多环芳烃全年总平均浓度为11.59 ng/m 3,季平均浓度范围在4.775~23.98 ng/m3之间,季节之间呈现一定的变化,冬季秋季春季夏季;全市大气PM 2.5中多环芳烃的苯并(a)芘总致癌等效浓度(TEQ)年均值为1.138 ng/m3,污染所致的成人和儿童的终身超额致癌风险分别为8.7×10-6和6.0×10-6,成人的预期寿命损失为44.5 min。     

甲苯污染场地基于人体健康的风险评估

某化工生产车间历史上发生甲苯泄漏,造成了现场的土壤和地下水污染。采用基于人体健康的风险评估以分析污染对敏感受体的风险,并确定污染物修复目标值和修复范围。结果表明,风险评估过程模型计算复杂,涉及参数众多,运用可信的风险评估商业软件可以快速模拟各种模式并进行计算,大大提高工作效率。     

The bumpy road to better risk control: A Tour d'Horizon of new concepts and ideas

How can we be sure that sufficient safeguards are in place and safety level is acceptable? As we heard Prof. Nancy Leveson stating at last year's MKOPSC symposium, even with all components functioning, dysfunctional component interaction can still be a cause of mishap. Human factor expert, Prof. Erik Hollnagel, asserts it in even stronger terms: the Efficiency-Thoroughness Trade-off principle, or rather dilemma, contends that one can hardly do it perfectly well. Perfect thoroughness, certainly in complex situations, requires an amount of time with which efficiency will be in conflict. For improved situational awareness, sufficient resilience, and adequate risk control, we must adopt a top-down system approach. Hazard scenarios possible in the system, with all its entangled interactions of hardware, procedures, and humans shall be identified bottom-up and causal relations made clear. Fortunately, in recent years two potentially helpful tools have become available: Blended Hazid, a vastly improved, heavily computerized system approach making use of HazOp and FMEA, and Bayesian networks, a tool to model cause–effect structures allowing inclusion of uncertainty information. Bayesian networks as an infrastructure enable also the use of indicator values to relate the result of safety management effectiveness, which expresses itself as safety attitude of employees, competence, workload, and motivation, with their effects on error and failure probability. This paper will explain the directions these developments are advancing and the openings they provide for further process safety research and risk assessment, which when applied will result in improved process risk control.     

Towards more detailed determination of third party impact on risk on natural gas pipelines: Influence of population density

The paper presents a refined way to quantify the effects of third party interference on risk that is posed on people by transmission pipelines for natural gas. The main focus is set on the influence of population density on risk. Using the interdisciplinary approach, the presented study combines the knowledge from relevant risk assessment recommendations, physical consequences of hazardous events, existing history databases of hazardous event frequencies and urban planning. A quantitative boundary between two most populated types of area was established. A flexible risk coefficient was determined for a suburban type of populated area that is dependent on average population density. Consequently, a new approach for determination of a hazard distance from the pipeline and area boundaries for calculation of average population density was presented. This differs from the established methods described in some guidelines, but is based on results of applied quantitative risk assessment. The final result is more accurate determination of risk levels in suburban areas. Described methods may serve as a supplement to the existing models for quantitative risk assessment on pipelines used in natural gas transportation and may be used by pipeline operators as well as policy- and decision makers.     

Numerical and reduced-scale experimental investigation of blast wave shape in underground transportation infrastructure

When an explosion occurs in a tunnel, the study of the blast wave quickly becomes complicated, owing to the multiple propagation patterns of the blast wave (incident wave, regular and Mach reflections) and to the geometrical conditions. Considering this problem, two patterns can be revealed. Near the explosive, the well-known free-field pressure wave can be observed. After multiple reflections on the tunnel's walls, this overpressure behaves like a one-dimensional (1D) wave. One aim of this paper is to determine the position of this transition spherical-to-planar wave propagation in a tunnel using both numerical and reduced-scale experiments, and thereby validate the dedicated law established in a previous work.For this purpose, a detonation of TNT in a tunnel with a cross-section of up to 55 m² is considered. Results show good agreement between the numerical simulations and experiments. The transition zone between the three-dimensional (3D) and the 1D wave is well detected. An application to a simplified subway station is also investigated which shows that significant planar waves can be transmitted to the neighboring stations via the junction tunnels.     

Current practices in the identification of critical habitat for threatened species

The term critical habitat is used to describe the subset of habitat that is essential to the survival and recovery of species. Some countries legally require that critical habitat of listed threatened and endangered species be identified and protected. However, there is little evidence to suggest that the identification of critical habitat has had much impact on species recovery. We hypothesized that this may be due at least partly to a mismatch between the intent of critical habitat identification, which is to protect sufficient habitat for species persistence and recovery, and its practice. We used content analysis to systematically review critical habitat documents from the United States, Canada, and Australia. In particular, we identified the major trends in type of information used to identify critical habitat and in occupancy of habitat identified as critical. Information about population viability was used to identify critical habitat for only 1% of the species reviewed, and for most species, designated critical habitat did not include unoccupied habitat. Without reference to population viability, it is difficult to determine how much of a species’ occupied and unoccupied habitat will be required for persistence. We therefore conclude that the identification of critical habitat remains inconsistent with the goal of protecting sufficient habitat to support persistence and recovery of the species. Ensuring that critical habitat identification aligns more closely with its intent will improve the accuracy of the designations and may therefore help improve the benefits to species recovery when combined with adequate implementation and enforcement of legal protections.     

A risk framework for preventing salinity

Salinity is an insidious soil conservation issue. Its expression can be greatly removed in time and space from its causes, so a focus on prevention is preferred. To avoid over or under-investment, a communication strategy for salinity needs to be a staged approach, the risks defined and the assets at risk identified.This paper describes a risk assessment schema and associated information base designed to support community investment in preventative actions. It describes a new approach to salinity risk similar to the concepts of diagnosis and staging used by physicians for diseases such as cancer. It outlines the diagnostic tools now being developed to define the timeframes of salinity development, the biophysical features of the landscape within which salinity develops and the riskiness of current and alternative management systems and matches this with a complementary community process designed to build knowledge and intervention. A GIS/database system captures the concepts of salinity risk and a large array of diagnostic information in a form designed for the development of salinity knowledge in the community and to guide investment in salinity prevention. The communication strategy and the salinity risk system are being applied in the Fitzroy Basin, Australia, an area of approximately 150,000 km² straddling the Tropic of Capricorn.     

Incorporating bioavailability into management limits for copper in sediments contaminated by antifouling paint used in aquaculture

Although now well embedded within many risk-based sediment quality guideline (SQG) frameworks, contaminant bioavailability is still often overlooked in assessment and management of contaminated sediments. To optimise management limits for metal contaminated sediments, we assess the appropriateness of a range methods for modifying SQGs based on bioavailability considerations. The impairment of reproduction of the amphipod, Melita plumulosa, and harpacticoid copepod, Nitocra spinipes, was assessed for sediments contaminated with copper from antifouling paint, located below aquaculture cages. The measurement of dilute acid-extractable copper (AE-Cu) was found to provide the most useful means for monitoring the risks posed by sediment copper and setting management limits. Acid-volatile sulfide was found to be ineffective as a SQG-modifying factor as these organisms live mostly at the more oxidised sediment water interface. SQGs normalised to %-silt/organic carbon were effective, but the benefits gained were too small to justify this approach. The effectiveness of SQGs based on AE-Cu was attributed to a small portion of the total copper being present in potentially bioavailable forms (typically <10% of the total). Much of the non-bioavailable form of copper was likely present as paint flakes in the form of copper (I) oxide, the active ingredient of the antifoulant formulation. While the concentrations of paint-associated copper are very high in some sediments, as the transformation of this form of copper to AE-Cu appears slow, monitoring and management limits should assess the more bioavailable AE-Cu forms, and further efforts be made to limit the release of paint particles into the environment.     

The need for attuned soil quality risk assessment for non-Western humans and ecosystems,exemplified by mining areas in South Africa

Worldwide, soils are under threat of deterioration and contamination due to anthropogenic activities. Whilst risk assessment of soils in Europe has been well studied, the same cannot be said of soils in Southern Africa. Soil screening values exist in SA, which enables soil quality assessment, but lack a clear risk-based scientific foundation and site-specific risk assessment. This is specified, in the light of the proximity of mine tailings disposal facilities to residential areas, exposing people to a wide range of possible contaminants. The aim of this paper is to give an overview of soil quality risk assessment with specific reference to European models, and to explore how these could be used in a Southern African context where soil quality risk assessment is a relatively new and insufficiently investigated field. Therefore, the attention in this paper is on typical non-Western conditions to which soil quality risk assessment has to be attuned.