Accounting for Climate Change: Introduction

The assessment of greenhouse gases (GHGs) emitted to and removed from the atmosphere is high on both political and scientific agendas internationally. As increasing international concern and cooperation aim at policy-oriented solutions to the climate change problem, several issues have begun to arise regarding verification and compliance under both proposed and legislated schemes meant to reduce the human-induced global climate impact. The approaches to addressing uncertainty introduced in this article attempt to improve national inventories or to provide a basis for the standardization of inventory estimates to enable comparison of emissions and emission changes across countries. Authors of the accompanying articles use detailed uncertainty analyses to enforce the current structure of the emission trading system and attempt to internalize high levels of uncertainty by tailoring the emissions trading market rules. Assessment of uncertainty can help improve inventories and manage risk. Through recognizing the importance of, identifying and quantifying uncertainties, great strides can be made in the process of Accounting for Climate Change.     

Application of the SOLVTM Process: A Total Systems Approach to Environmental Remediation

Commodore Solution Technologies, Inc. has developed an innovative total systems approach to environmental remediation that utilizes a patented chemistry called Solvated Electron Technology (SET^TM). Solvated electron solutions are some of the most powerful reducing agents know. Formed by dissolving alkali and alkaline-earth metals in anhydrous liquid ammonia to produce a solution of metal cations and free electrons, solvated electron solutions are capable of providing reductants of great activity and uniqueness. They provide a highly useful mechanism for the reductive destruction of many organic molecules and are extremely effective in the dehalogenation of halogenated organic compounds. Commodore has received a nation-wide EPA operating permit for the nonthermal destruction of PCBs using this process. The SoLV^TM process is a total solution approach that incorporates SET^TM with pre-and post-treatments, when necessary, for environmental cleanup. It is applicable to a broad range of substrates including liquids, solids, soils, and job materials. This article presents results from several pilot, field, and commercial validation studies utilizing the SoLV^TM process.     

1,2,4-三氯苯环境污染修复技术研究进展

综述了物理修复、化学修复、微生物修复及联合修复等几种主要的1,2,4-三氯苯(1,2,4-TCB)环境污染修复技术的研究进展。阐述了各种修复方法的反应原理、修复条件和效果,对比了各种修复方法的优缺点。提出今后的研究方向:解决物理吸附法修复1,2,4-TCB污染后的吸附剂的后续处理问题;优化化学降解1,2,4-TCB的工艺条件,避免二次污染,进行现场试验,实现工程应用;分离、培育1,2,4-TCB的优势降解菌种;深入研究联合修复技术的降解机理,实现1,2,4-TCB的高效、彻底降解。     

δ13C of Tree-Ring Lignin as an Indirect Measure of Climate Change

High-resolution paleoclimatic data are an essential requirement for testing numerical models of climate change and the global carbon cycle. If the long tree-ring chronologies, originally established for the purpose of dendrochronology, are to be fully exploited as an indirect measure of past climatic variability, additional techniques are required to obtain this information. The determination of the δ¹³C value of tree-ring cellulose has been used successfully to reconstruct past climates. However, under both aerobic and anaerobic conditions, the polysaccharide components of vascular plants (mainly cellulose and hemicelluloses) are more prone to rapid degradation than lignin. This has serious implications for the use of carbon isotope values of tree-ring cellulose as an indirect measure of past climates. An absolutely dated ring-width chronology was established for oaks (Quercus robur L.) growing at Sandringham Park in eastern England. Carbon isotope values were determined on α-cellulose and `Klason' lignin isolated from annual latewood samples over the period AD 1895–1999. The carbon isotope values of earlywood lignin are correlated with the latewood carbon isotope values of the previous year, supporting the theory that some of the carbon utilised in earlywood synthesis is assimilated in the previous year. The high-frequency variance in the carbon isotope indices of latewood lignin and cellulose is highly correlated with combined July and August environmental variables, indicating that they were formed at similar times. There was no evidence of secondary lignification. These resultsdemonstrate that the determination of carbon isotope values of latewood lignin offers the potential to obtain unambiguous proxy climatic data covering several millennia.     

十溴联苯醚环境修复技术的研究进展

介绍了溴代阻燃剂十溴联苯醚（BDE-209）环境修复技术的研究进展。从光降解、零价铁降解、生物降解3个方面对BDE-209的降解机理和降解后的产物进行了介绍。BDE-209经光照、厌氧微生物、零价铁的脱溴作用后,降解成低溴代联苯醚产物;好氧微生物利用低溴代联苯醚作为生长碳源,将其在酶的作用下开环降解,进入三羧酸循环或彻底分解成CO₂和H₂O。提出应采用多种方法协同作用,更有效地降解多溴联苯醚化合物。     

Environmental Effects Monitoring in Sydney Harbor During Remediation of One of Canada's Most Polluted Sites: A Review and Lessons Learned

This article reviews a comprehensive marine environmental effects monitoring program (MEEMP) comprised of components capable of detecting changes in the marine environment over short or extended temporal scales during remediation of one of Canada's most polluted sites at the Sydney Tar Ponds. The monitoring components included: water and sediment quality, amphipod toxicity testing, mussel tissue, crab hepatopancreas tissue, and benthic community assessments. The MEEMP was designed to verify the impact predictions for the remediation project (i.e., no immediate damage to the marine ecosystem through remediation activities). Some components were capable of providing conclusive data (e.g., sediment and water quality), while others only yielded data that were inconclusive or difficult to attribute to remediation activities (e.g., intertidal community assessments and amphipod toxicity testing). Components that provided only inconclusive results or were difficult to attribute to remediation activities were discontinued, resulting in substantial cost savings during the project, but without compromising the overall objectives of the program, which was to monitor for potential adverse environmental effects of remediation on the marine environment in Sydney Harbor and to verify environmental effects predictions made in the Environmental Impact Statement for the project. The rationale for discontinuing certain MEEMP components and discussion of conclusive results are incorporated into “lessons learned” for environmental remediation practitioners and regulators working on similar large‐scale multiyear remediation projects. © 2014 Wiley Periodicals, Inc.     

Remediation of an oily leachate pond in Estonia.

Until recent years, waste oil and oil-contaminated waters commonly ended up in landfills. At some dump sites, ponds of oily liquids and leachate were formed. To remediate such ponds, an interdisciplinary approach is now required, keeping costs at an affordable level, particularly in countries with changing economies. From 1974 to 1993, liquid oily wastes taken to the Laguja landfill, in Estonia, were disposed of in a pond with a surface area of 9800 m2. It was estimated that the pond contained 4500-6000 m3 of oily water and 3500 m3 of oil-containing bottom sediments. This study aimed at developing an environmentally sound and cost-effective method for remediation of the oily liquids, leachate and contaminated underlying sediment material, to meet the existing legal demands. It was concluded that treatment of contaminated water is well established and the procedures carried out to meet the regulatory demands achieved satisfactory results. However, regarding treatment of sediments it was concluded that legal and technological aspects, as well as monitoring procedures are not fully established and are usually underestimated. Laboratory investigations can provide valuable information in decision-making, and contribute to effective full-scale remediation planning.     

Quantitative Environmental Footprints and Sustainability Evaluation of Contaminated Land Remediation Alternatives for Two Case Studies

Since the US Environmental Protection Agency (US EPA) launched its “green remediation” program and EU member states began to reassess their national regulations for environmental remediation in order to reach a Europe‐wide consensus on policy and standards, the need and interest for sustainable remediation of contaminants from brownfields has grown considerably. Concomitantly, the ability to calculate and assess the suitability as well as the environmental footprints and associated risks of a growing number of remediation techniques has become a priority. The authors quantitatively evaluate the differences between various remediation techniques, and for this purpose, a number of ex situ and in situ remediation techniques are adapted to model 21 remediation scenarios for two contaminated sites in the Gothenburg region of Sweden: the Bohus Varv site on the Göta älv river bank and the Hexion site in Mölndal. A wide range of quantitative results for these models are presented, compared, and analyzed. Based on the results from both projects, it is concluded that: (1) remediation techniques requiring long distance residual transportation have significant footprints, except the transportation of contaminated residuals by train due to Swedish energy production conditions; (2) residual transportation by ship results in much higher SO_x, NO_x, and particle releases compared to the other alternatives; and (3) residual transporation by truck results in high accident risks. Finally, activities powered by electricity result in a reduced footprint compared to activities powered by fossil fuels, considering Swedish energy production conditions. The authors conducted a cross‐benefit analysis of SiteWise^TM applications which recognizes its potential as a tool for presenting life cycle assessment analyses with appropriate system boundary definitions and an easy inventory analysis process. Results from this tool provide valuable support to decision makers aiming at more sustainable remediation. © 2013 Wiley Periodicals, Inc.     

Risk Assessment in Remediation: Accurately Accounting for Uncertainty

Cleanup levels at hazardous waste sites are typically developed based at least in pan on either generic or site-specific risk assessments. Risk assessment in its purest form should be a measure of the potential for a site to cause adverse effects and therefore should be used as the basis for cleanup. However, the process of risk assessment continues to be subject to problems, primarily related to inherent uncertainties in the exposure parameters and toxicity criteria that are the building blocks of the risk assessment. Criticism of risk assessments and risk-based decisions range from comments that the process inadequately protects human health to comments that the process is overly protective, and examples of both ends of the spectrum are readily available. Site remediation professionals should be aware of the issues related to uncertainty and understand the potential problems in order to ensure appropriate and effective site cleanup. © 1999 John Wiley & Sons, Inc.     

Remediation of a Diffuse Trichloroethene Plume in an Urban Setting

During an environmental assessment of a former fleet vehicle maintenance facility located in Jacksonville, Florida, dissolved trichloroethene (TCE) concentrations exceeding the Florida groundwater standard (3 micrograms per liter) were detected at a depth of 40 feet (12 meters) below land surface (bls). A plume was delineated that measured approximately 600 feet (183 meters) by 150 feet (46 meters), extending across a major road and onto adjacent properties. Shaw Environmental, Inc., which was acquired by CB&I in February 2012, performed pilot tests with in situ oxygen curtain (iSOC), and the injection of Anaerobic Biochem Plus (ABC+), a mixture of lactates, a phosphate buffer, fatty acids, and zero‐valent iron. Based on the pilot‐test results, ABC+ appeared the more effective of the two methods and was selected for full‐scale implementation. In February 2011, Shaw Environmental, Inc. and a subcontractor used direct‐push technology to inject ABC+ in 120 borings. By September 2011, the treatment succeeded in lowering the concentrations of TCE to below the Florida standard in all impacted wells. Subsequent sampling events indicate that TCE concentrations have remained below the standard, but sampling continues for iron, which is decreasing but remains slightly elevated. © 2013 Wiley Periodicals, Inc.     

Chelating Ability and Microbial Stability of an <Emphasis Type="SmallCaps">l</Emphasis>-Arginine-Modified Chitosan-Based Environmental Remediation Material

To improve the heavy metal ion chelating ability and the microbiological stability of chitosan (CS), l-arginine (l-Arg) was grafted on CS polymer in the presence of the condensing agent 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) and the coupling reagent N-hydroxysuccinimide (NHS) to prepare a natural polymer-based environmental rehabilitation material: l-arginine-grafted chitosan (CA). The graft mechanism is discussed, and the reaction conditions were optimized. The product was characterized using elemental analysis, infrared spectroscopy (FT-IR) and ¹³C-NMR spectroscopy (¹³C-NMR). The optimal reaction conditions were a reactant molar ratio nCS:nArg:nEDC:nNHS of 3:3:3:1, a reaction time of 12 h, and a reaction system pH?=?5. Under these conditions, the grafting ratio (GR) was 16.85%, while the product yield (PY) was 90.48%. The results of the adsorption experiments showed that the CA (GR?=?16.85%) had a better removal capacity for highly concentrated Cu²⁺ and Ni²⁺ ions than CS. The antibacterial activity of the CA was also enhanced. When the GR reached 16.85%, the CA almost completely inhibited the growth of colibacillus and Staphylococcus aureus. Due to its high chelating ability and microbiological stability, this novel metal-ion adsorption material, CA, can be considered to have broad application potential in heavy metal ion-polluted water and soil remediation.     

Application of an Adapted Version of MT3DMS for Modeling Back‐Diffusion Remediation Timeframes

Simulation of back‐diffusion remediation timeframe for thin silt/clay layers, or when contaminant degradation is occurring, typically requires the use of a numerical model. Given the centimeter‐scale vertical grid spacing required to represent diffusion‐dominated transport, simulation of back‐diffusion in a 3‐D model may be computationally prohibitive. Use of a local 1‐D model domain approach for simulating back‐diffusion is demonstrated to have advantages but is limited to only some applications. Incorporation of a local domain approach for simulating back‐diffusion in a new model, In Situ Remediation‐MT3DMS (ISR‐MT3DMS) is validated based on a benchmark with MT3DMS and comparisons with a highly discretized finite difference numerical model. The approach used to estimate the vertical hydrodynamic dispersion coefficient is shown to have a significant influence on the simulated flux into and out of silt/clay layers in early time periods. Previously documented back‐diffusion at a Florida site is modeled for the purpose of evaluating the sensitivity of the back‐diffusion controlled remediation timeframe to various site characteristics. A base case simulation with a clay lens having a thickness of 0.2 m and a length of 100 m indicates that even after 99.96 percent aqueous TCE removal from the clay lens, the down‐gradient concentrations still exceed the MCL in groundwater monitoring wells. This shows that partial mass reduction from a NAPL source zone via in situ treatment may have little benefit for the long‐term management of contaminated sites, given that back‐diffusion will sustain a groundwater plume for a long period of time. Back‐diffusion model input parameters that have the greatest influence on remediation timeframe and thus may warrant more attention during field investigations, include the thickness of silt/clay lenses, retardation coefficient representing sorbed mass in silt/clay, and the groundwater velocity in adjacent higher permeability zones. Therefore, pump‐and‐treat systems implemented for the purpose of providing containment may have an additional benefit of reducing back‐diffusion remediation timeframe due to enhanced transverse advective fluxes at the sand/clay interface. Remediation timeframes are also moderately sensitive to the length of the silt/clay layers and transverse vertical dispersivity, but are less sensitive to degradation rates within silt/clay, contaminant solubility, contact time, tortuosity coefficient, and monitoring well‐screen length for the scenarios examined. ©2015 Wiley Periodicals, Inc.     

A Cost Comparison of Organic versus Inorganic Ion Exchange Resin for Remediation of High-Level Waste

Ion exchange (IX) can be used to aid in the remediation of underground storage tank (UST) radioactive waste at the U.S. Department of Energy's Hanford site in the state of Washington. In particular, IX can be used to concentrate the radionuclides in liquid-based waste prior to immobilization for final disposal. Concentration of the radionuclides can significantly reduce the final immobilized high-level waste volume and consequent overall remediation cost. Organic and inorganic IX resins each have unique advantages and disadvantages regarding the remediation process. This study presents a comparison of the remediation cost for UST waste at Hanford for a phenol-formaldehyde type organic resin versus crystalline silico-titanate inorganic resin. It was determined that with optimum processing conditions such as waste blending and sludge washing, remediation with the inorganic resin would be less expensive than the organic resin. Assuming baseline remediation conditions, the use of inorganic rather than organic IX resin for UST remediation at Hanford can save approximately $383 million. A limited sensitivity analysis was performed as pan of this study and is reported in the following. © 1999 John Wiley & Sons, Inc.     

Successful Deployment of an Innovative Environmental Technology: The Terra-Kleen Experience

The National Research Council's report, Innovations in Ground Water and Soil Cleanup: From Concept to Commercialization, reviewed the implementation of innovative remediation technologies and portrayed a bleak outlook for them. Conversely, Terra-Kleen has invented, patented, permitted, and profited through the use of an innovative technology in the current market. Terra-Kleen has implemented a solvent extraction technology for the removal of PCBs, PAHs, and chlorinated pesticides from soil, sediment, and debris. To date, Terra-Kleen has successfully processed over 23 million pounds of PCB-contaminated soil in Alaska, California, Florida, Ohio, and Oklahoma. The company has been profitable each year since its inception, and has averaged a revenue growth rate of 94 percent per year for the last four years. Corporate growth has been financed entirely through profits and conventional bank loans at favorable interest rates. This article reviews the factors that have led to Terra-Kleen's success, overviews the solvent extraction technology, and details specific projects that have implemented the technology.     

Chemical Changes in Sediment Pore-Waters of an Acidic Mining Lake After Addition of Organic Substrate and Lime for Stimulating Lake Remediation

In the past five years, enclosures have beeninstalled in an acidic mining lake in Lusatia to investigate insitu remediation processes. They were treated with straw, withstraw and Carbokalk, or with Carbokalk alone, where Carbokalkis a by-product of the sugar industry (solid precipitate ofnon-sugars after lime clarification of extracted sugar beetjuice). Sediment samples were taken as cores to get informationabout the behaviour of organic and inorganic components insediment pore-water with depth. Vertical distributions of pH,soluble reactive phosphate, nitrate, ammonium, silica,aluminium, iron, manganese, calcium, magnesium, sodium,potassium, sulphate, and DOC were measured. The resultingprofiles, each consisting of 15 data points at differentdepths, were compared by cluster analysis. The similarities ofsediment cores from different treated enclosures relating toprofiles of chemical components were discussed. Increasedconcentrations of potassium and sulphate were found in pore-water after substrate treatment. The data imply dissolution ofpotassium iron sulphate hydroxide minerals (jarosite) after anincrease of pH caused by dissolution of lime and by sulphatereducing processes which were stimulated by organic substrateaddition.