Methodology for conducting screening-level ecological risk assessments for hazardous waste sites. Part I: overview

The Idaho National Engineering and Environmental Laboratory (INEEL) is a Department of Energy (DOE) facility. To assess the impact of the site activities and releases on ecological receptors, the INEEL implemented a phased approach for conducting ecological risk assessments (ERAS). This approach applies an iterative, 'tiered' process, in which conservative preliminary assessments support progressively more refined assessments. The first phase is the screening-level ERA, which is a 'preassessment' performed at the Waste Area Group (WAG) level. This paper will address innovative methods, at the screening level, used to address systematically the complexity of the INEEL site, including adaptations of existing ERA methodologies to accommodate the functional grouping approach.     

Methodology for conducting screening-level ecological risk assessments for hazardous waste sites. Part III: exposure and effects assessment

The Idaho National Engineering and Environmental Laboratory (INEEL) has implemented a phased approach to ecological risk assessment (ERA). The first step in this process is a screening-level ERA at each facility. Basic to this approach was the development of ecologically based screening levels (EBSLs), defined as concentrations of chemicals in soil (or other media) that are not expected to produce any adverse effects on selected ecological receptors under chronic exposure conditions (analogous to preliminary remediation goals or soil screening levels). EBSLs are calculated by rearrangement of standard exposure equations to solve for soil concentration when chemical intake rate is set at a developed toxicity reference value (TRV). A TRV is defined as a chronic dose that is likely to be without appreciable risk of deleterious effects. This definition was extended to define TRVs and ultimately EBSLs for the functional groups used in the INEEL screening-level ERAS.     

Making cleanup decisions at hazardous waste sites: the clean sites approach.

This paper provides a summary of the results of an 18-month study conducted by Clean Sites, Inc. of Alexandria, Virginia. The study was designed to take a critical look at the way remedies are selected for abandoned hazardous waste sites that are cleaned up under the authority of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or Superfund) and to develop recommendations for improving that process. The recommendations were released in an October 1990 report entitled "Improving Remedy Selection: An Explicit and Interactive Process for the Superfund Program." Through a cooperative agreement with the U.S. Environmental Protection Agency, Clean Sites is working to test these recommendations. At two actual Superfund sites, Clean Sites will assist EPA in performing the remedy selection in accordance with the process Clean Sites has developed.     

Haloacetic acids in the aquatic environment. Part II: ecological risk assessment

Haloacetic acids (HAAs) are environmental contaminants found in aquatic ecosystems throughout the world as a result of both anthropogenic and natural production. The ecological risk posed by these compounds to organisms in freshwater environments, with a specific focus on aquatic macrophytes, was characterized. The plants evaluated were Lemna gibba, Myriophyllum spicatum and M. sibiricum and the HAAs screened were monochloroacetic acid (MCA), dichloroacetic acid (DCA), trichloroacetic acid (TCA), trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CDFA). Laboratory toxicity data formed the basis of the risk assessment, but field studies were also utilized. The estimated risk was calculated using hazard quotients (HQ), as well as effect measure distributions (EMD) in a modified probabilistic ecological risk assessment. EMDs were used to estimate HAA thresholds of toxicity for use in HQ assessments. This threshold was found to be a more sensitive measure of low toxicity than the no observed effect concentrations (NOEC) or the effective concentration (EC10). Using both deterministic and probabilistic methods, it was found that HAAs do not pose a significant risk to freshwater macrophytes at current environmental concentrations in Canada, Europe or Africa for both single compound and mixture exposures. Still, HAAs are generally found as mixtures and their potential interactions are not fully understood, rendering this phase of the assessment uncertain and justifying further effects characterization. TCA in some environments poses a slight risk to phytoplankton and future concentrations of TFA and CDFA are likely to increase due to their recalcitrant nature, warranting continued environmental surveillance of HAAs.     

Soil remediation techniques at uncontrolled hazardous waste sites. A critical review

The objective of this critical review is to address soil remediation techniques at uncontrolled hazardous waste sites with regard to the following areas: 1) important regulatory and technical issues and information needs concerning soil remediation at uncontrolled hazardous waste sites; 2) approaches for selection of remediation techniques; and 3) the current state of knowledge regarding soil remediation techniques, including applications and limitations. The areas identified above are addressed with regard to current information, selected milestone publications, and specific applications of technologies to provide a synthesis of the topic. The information concerning current issues, approaches, and soil remediation techniques presented was critically reviewed in order to: 1) identify deficiencies in current approaches; 2) develop a conceptual framework for remediation; and 3) recommend improved approaches for selection of remediation technologies.     

Comparative analysis of health risk assessments for municipal waste combustors

Quantitative health risk assessments have been performed for a number of proposed municipal waste combustor (MWC) facilities over the past several years. This article presents the results of a comparative analysis of a total of 21 risk assessments, focusing on seven of the most comprehensive methodologies. The analysis concentrates on stack emissions of noncriteria pollutants and is comparative rather than critical in nature. Overall, the risk assessment methodologies used were similar whereas the assumptions and input values used varied from study to study. Some of this variability results directly from differences in site-specific characteristics, but much of it is due to absence of data, lack of field validation, lack of specific guidelines from regulatory agencies, and reliance on professional judgment. The results indicate that carcinogenic risks are more significant than chronic non-carcinogenic risks. In most instances polychlorodibenzodioxins, polychlorodibenzofurans, and cadmium contribute more significantly to the total carcinogenic risk from MWC stack emissions than other contaminants. In addition, the contribution to total risk of all indirect routes of exposure (ingestion and dermal contact) exceeds that of the direct inhalation route for most studies reviewed.     

危险废物事故排放的河流水环境健康风险评价

分析了基于水体中污染物迁移转化方程的水质预测模型,并借鉴美国环保局推荐使用的健康风险评价模型,建立了一种危险废物事故排放时水环境对人体健康风险的评价方法。以电镀污泥为例验证了该方法的有效性。结果显示:该方法需要参数少且计算简单;电镀污泥中目标污染物(Cr、Cu、Ni、Zn)所引起的河流水环境非致癌风险(1.67)超过了美国标准中的可接受风险水平1.00,不可接受;致癌风险(0.88E-11)则小于美国标准中的可接受风险水平1.00E-06,风险不明显。     

危险废物城市环境风险评估方法及案例研究

在不同经济社会发展情况下,危险废物的风险源危险性和风险受体脆弱性存在很大差异。因此,城市对危险废物采取的风险防控和应急措施应该因城市而异。然而,目前我国大部分城市对危险废物的管理仍然是全过程从严管理,并未建立基于风险评估的环境管理体系。本研究以城市为边界,从危险废物的风险源危险性、风险受体脆弱性和风险防控与应急能力3个维度构建评估指标体系,然后在层次分析法的基础上,采用等比例分配法对指标进行赋权,并运用线性加权法合成经过正向化处理的指标评分值,从而得出危险废物城市环境风险评估结果。通过计算3个维度评分值的耦合度,可以确定风险防控与应急能力维度与风险源危险性维度和风险受体脆弱性维度的匹配程度。运用该方法对深圳市开展案例研究,结果表明,深圳市在“无废城市”建设试点期间,主要通过提升风险防控与应急能力,将危险废物城市环境风险值降低了20.7%;并且风险防控与应急能力维度与风险源危险性维度和风险受体脆弱性维度的匹配度较高,属于高风险高能力城市。因此,建议深圳市在下一步工作中,继续完善涉危险废物项目环境准入审查,严格评估危险废物再利用安全,不断加强信息化手段在环境监管中的应用,避免涉危险废物突发环境事件的发生,全面降低危险废物对城市造成的环境风险。     

Towards sets of hazardous waste indicators. Essential tools for modern industrial management

Decision-makers require useful tools, such as indicators, to help them make environmentally sound decisions leading to effective management of hazardous wastes. Four hazardous waste indicators are being tested for such a purpose by several countries within the Sustainable Development Indicator Programme of the United Nations Commission for Sustainable Development. However, these indicators only address the 'down-stream' end-of-pipe industrial situation. More creative thinking is clearly needed to develop a wider range of indicators that not only reflects all aspects of industrial production that generates hazardous waste but considers socio-economic implications of the waste as well. Sets of useful and innovative indicators are proposed that could be applied to the emerging paradigm shift away from conventional end-of-pipe management actions and towards preventive strategies that are being increasingly adopted by industry often in association with local and national governments. A methodological and conceptual framework for the development of a core-set of hazardous waste indicators has been developed. Some of the indicator sets outlined quantify preventive waste management strategies (including indicators for cleaner production, hazardous waste reduction/minimization and life cycle analysis), whilst other sets address proactive strategies (including changes in production and consumption patterns, eco-efficiency, eco-intensity and resource productivity). Indicators for quantifying transport of hazardous wastes are also described. It was concluded that a number of the indicators proposed could now be usefully implemented as management tools using existing industrial and economic data. As cleaner production technologies and waste minimization approaches are more widely deployed, and industry integrates environmental concerns at all levels of decision-making, it is expected that the necessary data for construction of the remaining indicators will soon become available.     

Yard waste compost as a stormwater protection treatment for construction sites.

Runoff water quality improvement from three yard waste compost erosion control treatments were compared with two conventional treatments and an untreated control on plots of 3:1 slope during two growing seasons, using natural events and simulated rainfall. Runoff volume, suspended solids, nutrients, biomass, turf shear strength, and turfgrass color scale were monitored. The most effective compost treatment, a 5-cm thick blown compost blanket, produced 12.7 times less runoff and 9.8 times less sediment load than a straw mat and silt fence treatment. The compost treatments generated eight times more biomass than the straw mat treatments. Root development was significantly better on the compost treatments based on turf shear strength measurements. Tilled-in compost was not as effective as a compost blanket at reducing sediment loss, particularly before the establishment of grass on the plot. The cost of compost treatments was similar to that of straw mat with silt fence treatments.     

Environmental risks of chemicals and genetically modified organisms: a comparison. Part II: Sustainability and precaution in risk assessment and risk management

The principles of precaution and sustainability require more consideration in the assessment of environmental risks posed by chemicals and genetically modified organisms. Instead of applying risk reduction measures when there are serious indications for damage, full scientific certainty is often waited for before taking action. The precautionary principle particularly should be applied in those cases in which the extent and probability of damage are uncertain, e.g. in the case of persistent chemicals which are additionally bioaccumulative or highly mobile. Based on these principles, environmental action targets for risks associated with GMOs and chemicals can be developed. Risk management not only includes statutory measures but also instruments designed to influence behaviour indirectly are important to achieve the goals. Particularly for risks of GMOs which provoke fear, risk communication is important. Some rules to which attention should be paid in communication with the public are presented.     

A case study for demonstrating the application of U.S. EPA's monitored natural attenuation screening protocol at a hazardous waste site

Natural attenuation assessment data, collected at a Superfund site located in Louisiana, USA, are presented. The study site is contaminated with large quantities of DNAPL waste products. Source characterization data indicated that chlorinated ethene and ethane compounds are the major contaminants of concern. This case study illustrates the steps involved in implementing the U.S. EPA's [U.S. EPA, 1998. Technical protocol for evaluating natural attenuation of chlorinated solvents in ground water, by Wiedmeier, T.H., Swnason, M.A., Moutoux, D.E., Gordon, E.K., Wilson, J.T., Wilson, B.H., Kampbell, D.H., Hass, P.E., Miller, R.N., Hansen, J. E., Chapelle, F.H., Office of Research and Development, EPA/600/R-98/128] monitored natural attenuation (MNA) screening protocol at this chlorinated solvent site. In the first stage of the MNA assessment process, the field data collected from four monitoring wells located in different parts of the plume were used to complete a biodegradation scoring analysis recommended by the protocol. The analysis indicates that the site has the potential for natural attenuation. In the second stage, a detailed conceptual model was developed to identify various contaminant transport pathways and exposure points. The U.S. EPA model and BIOCHLOR was used to assess whether the contaminants are attenuating at a reasonable rate along these transport paths so that MNA can be considered as a feasible remedial option for the site. The site data along with the modeling results indicate that the chlorinated ethene and chlorinated ethane plumes are degrading and will attenuate within 1000 ft down gradient from the source, well before reaching the identified exposure point Therefore, MNA can be considered as one of the feasible remediation options for the site.     

Decomposition of organohalogen compounds in municipal solid waste incineration plants. Part I: Chlorofluorocarbons

Disposal of chlorofluorocarbons in a municipal solid waste incinerator has been studied. Destruction of CFC-11 (trichloromonofluoromethane) and CFC-113 (trichlorotrifluoroethane) was found to be better than 99.9%. Neither emission limits for hydrogen chloride or hydrogen fluoride specified in the 17^th BImSchV are exceeded during CFC incineration nor could formation of toxic halogenated organic compounds like dibenzo-p-dioxins or dibenzofurans be observed.     

Siting a municipal solid waste disposal facility,Part II: The effects of external criteria on the final decision

The procedure of a multi-criteria decision analysis supported by the geographic information systems was applied to the site selection process of a planning municipal solid waste management practice based on twelve different scenarios. The scenarios included two different decision tree modes and two different weighting models for three different area requirements. The suitability rankings of the suitable sites obtained from the application of the decision procedure for the scenarios were assessed by a factorial experimental design concerning the effect of some external criteria on the final decision of the site selection process. The external criteria used in the factorial experimental design were defined as “Risk perception and approval of stakeholders” and “Visibility”. The effects of the presence of these criteria in the decision trees were evaluated in detail. For a quantitative expression of the differentiations observed in the suitability rankings, the ranking data were subjected to ANOVA test after a normalization process. Then the results of these tests were evaluated by Tukey test to measure the effects of external criteria on the final decision. The results of Tukey tests indicated that the involvement of the external criteria into the decision trees produced statistically meaningful differentiations in the suitability rankings. Since the external criteria could cause considerable external costs during the operation of the disposal facilities, the presence of these criteria in the decision tree in addition to the other criteria related to environmental and legislative requisites could prevent subsequent external costs in the first place.

Implications:

An experimental design was applied to a siting process based on different scenarios. The suitability rankings of suitable sites were obtained for each scenario. The external criteria used in the design were defined as perception and visibility. The presence of the external criteria produced meaningful differentiations. Two widespread persuasions about site selection were disproved using the results.     

Biosolids-amended soils: Part II. Chemical lability as a measure of contaminant bioaccessability.

Biosolids recycling by amending agricultural soils has increased significantly over the last few decades. The presence of contaminants in small, bioavailable quantities has generated concerns about health threats resulting from accumulation of potential toxins in the food chain. In this study, land application of biosolids was evaluated for environmental risk. Chemical lability tests for metals were used for the test soils and included analyses for water soluble, exchangeable, and metals extractable by the physiologically based extraction test. Chemical extractions detected slight increases in labile metal concentrations for many of the treated soils, particularly those receiving long-term applications of 5 years or more. Significantly higher metal concentrations were observed in the soils that had been exposed to biosolids before the U.S. Environmental Protection Agency (Washington, D.C.) 503 Rule (U.S. EPA, 2004) was implemented.     

Assessment of aliphatic-aromatic copolyester biodegradable mulch films. Part II: laboratory simulated conditions

In a previous paper, we demonstrated that the main mechanism of degradation of poly(butylene adipate-co-terephthalate) (PBAT) biodegradable mulch films when exposed to field conditions was crosslinking due to the photodegradation from solar radiation. The aim of this work was to determine the effect of crosslinking on the biodegradability of PBAT samples. PBAT films were subjected to UV photodegradation in laboratory simulated conditions to investigate the effects of crosslinking and other major changes in the structure and mechanical properties of the films. Crosslinking caused the films to become more brittle and produced a reduction of the tensile strength and percent elongation. Besides the crosslinking degradation mechanism, chain scission also occurred in the samples. After 45d of biodegradation test, the non-crosslinked PBAT sample reached 60% of mineralization. However, the percent mineralization was reduced when samples were crosslinked. The percent mineralization of samples with 10%, 30%, 50%, and 70% gel content was 36%, 43%, 21%, and 24%, respectively. Our results indicate that crosslinking is a key process underlying the degradation of the PBAT film and did affect the biodegradability of the films, since the samples with greater amount of gel content generally showed less percent mineralization in the biodegradation tests.     

Flotation of metal-loaded clay anion exchangers. Part II: the case of arsenates

Hydrotalcite-like materials, or otherwise termed layered double hydroxides, are clays with an ability to remove anions. As they usually are in powder form, these sorbents often present appreciable problems in the solid/liquid separation process following the sorption stage. Sorptive flotation of metal-loaded particles was investigated in this paper, as an alternative two-stage process. In the sorption process, satisfactory removals of arsenic(V) were obtained onto synthetic hydrotalcite particles from water. The effect of some parameters, like the solution ionic strength, concentrations, temperature, etc. was examined. During the second stage of the process, hydrotalcite fine particles were removed from the liquid phase by dispersed-air flotation; various surfactants were tested in relation to the ionic strength of the solution. The combined process of sorptive flotation provides promising results for arsenic removal.     

Environmental product attributes in end-of-life management in the UK. Part I: an end-of-life eco-declaration for waste IT and office equipment

The focus of this paper and its companion (Part II) is to identify producer responsibility associated with the proposed Waste from Electrical and Electronic Equipment (WEEE) Directive and the need for greater information about the environmental attributes of electrical and electronic equipment to facilitate end-of-life management of discarded products. Recently, a wide-ranging debate has started within the IT industry centred on the best way to define the exact nature of the information that needs to be supplied to recyclers by producers in order to comply with the proposed European Commission Directive. Using IT and office equipment as an indicative example, semi-structured telephone interviews were conducted with representatives of the UK electronics end-of-life management industry about the environmental attributes that are needed for compliance with the draft Directive. The results of this research indicate there is specific information about equipment that is required on a regular basis, the most important of which is centred on hazardous substances and materials contained in whole units, parts and components of that equipment. The content of an eco-declaration for end-of-life management of IT and office equipment derived from quantitative and qualitative interview data is presented.