Zinc,lead, and cadmium tolerance and accumulation in Cistus libanotis,Cistus albidus,and Cistus salviifolius: Perspectives on phytoremediation

Heavy metal contamination is of particular concern for human health and the environment. Phytoremediation is an emerging cost‐effective strategy to remediate heavy metal contaminated soil. However, this technique is limited by the small number of plants that are tolerant to heavy metals and are also accumulators. This study assayed zinc, lead, and cadmium tolerance and accumulation in Cistus libanotis, Cistus albidus, and Cistus salviifolius. The plants were cultivated in hydroponic conditions and exposed to different concentrations of Pb(NO₃)₂ (100 and 200 µM), ZnSO₄ (100 and 200 µM), or CdCl₂ (10 and 20 µM) for 3 weeks. Plant biomass and metal accumulation in roots and aboveground parts varied greatly among the species. All three species appeared to be sensitive to Zn. However, C. albidus displayed strong tolerance to Pb and accumulated large quantities of Pb and Cd in its roots. C. libanotis accumulated large quantities of Pb and Cd in its aboveground parts. C. libanotis can thus be classified as a Pb and Cd accumulator species. The study results show that C. albidus is suitable for phytostabilization of Pb‐contaminated soils, while C. libanotis can be used for phytoextraction of both Pb and Cd.     

Past, present, and future of MSW landfills in Japan

This article focuses on the historical development of landfill technology since the beginning of the nineteenth century in Japan. The regulations and guidelines that form a framework for the technology are reviewed, and the historical background and the current state of Japanese municipal solid waste (MSW) management are described. Through the analysis of data collected from facility leaflets, changes in the leachate treatment system are surveyed. Finally, the concept of the “sustainable bioreactor landfill with low organics” is proposed.     

Remediation,land use,and risk at Rocky Flats,and a comparison with Hanford

US Department of Energy (US DOE) responsibilities for its former national atomic weapons complex include remediation of the Rocky Flats facility near Denver, Colorado. In 1993, the site's primary mission shifted from “production'' of plutonium components for atomic weapons to cleanup of extensive radioactive and chemical contamination representing the legacy of production activities. Remediation was governed by the agreements between the US DOE as the responsible party and the US Environmental Protection Agency and the state of Colorado as joint regulators. In 1995, the Rocky Flats Future Use Working Group issued its final report, recommending among other features that long‐term cleanup reduce contamination levels to background. This article describes the circumstances that led the US DOE to complete the Rocky Flats cleanup more quickly and makes comparisons to the situation at the US DOE's Hanford site. © 2011 Wiley Periodicals, Inc.     

Superfund site remediation by landfilling—overview of landfill design,operation, closure,and postclosure issues

This article discusses the appropriateness of using landfills as part of remediating hazardous chemical and Superfund sites, with particular emphasis on providing for true long‐term public health and environmental protection from the wastes and contaminated soils that are placed in the landfills. On‐site landfilling or capping of existing wastes is typically the least expensive approach for gaining some remediation of existing hazardous chemical/Superfund sites. The issues of the deficiencies in US EPA and state landfilling approaches discussed herein are also applicable to the landfilling of municipal and industrial solid “nonhazardous” wastes. These deficiencies were presented in part as “Problems with Landfills for Superfund Site Remediation” at the US EPA National Superfund Technical Assistance Grant Workshop held in Albuquerque, New Mexico, in February 2003. They are based on the author's experience in investigating the properties of landfill liners and the characteristics of today's landfills, relative to their ability to prevent groundwater pollution and to cause other environmental impacts. Discussed are issues related to both solid and hazardous waste landfills and approaches for improving the ability of landfills to contain wastes and monitor for leachate escape from the landfill for as long as the wastes in the landfill will be a threat. © 2004 Wiley Periodicals, Inc.     

Applied geologic,microbiological, and engineering constraints of in-situ BTEX bioremediation

An in-situ bioremediation project has been designed and constructed for a site in south-central Kansas just north of Wichita. A pipeline leaked an unknown quantity of refinedfuels in the 1970s. The spill was undetected until hydrocarbons were found in a nearby municipal water supply well. Of concern, from a regulatory perspective, are the alkylbenzene components found in the groundwater, including benzene, toluene, ethylbenzene, and xylene (BTEX). Initial abatement procedures, including free product removal and pumping, had become ineffective. In-situ bioremediation was selected to complete the restoration process. The project emphasizes the need for a strong understanding of the geologic and hydrogeologic conditions prevalent under the site. Site studies were conducted to determine the distribution and mass of the contaminant and the hydraulic regime. Laboratory microbial studies were used to determine the efficacy of nitrate as a primary electron acceptor. Information from site studies was used to design a treatment system tailored to the requirements of the site. The treatment system is designed to deliver the maximum amount of nutrient-enriched water to the contaminated zone while maintaining hydraulic control of the site.     

Stabilization of As, Cr, Cu, Pb and Zn in soil using amendments--a review

The spread of contaminants in soil can be hindered by the soil stabilization technique. Contaminant immobilizing amendments decrease trace element leaching and their bioavailability by inducing various sorption processes: adsorption to mineral surfaces, formation of stable complexes with organic ligands, surface precipitation and ion exchange. Precipitation as salts and co-precipitation can also contribute to reducing contaminant mobility. The technique can be used in in situ and ex situ applications to reclaim and re-vegetate industrially devastated areas and mine-spoils, improve soil quality and reduce contaminant mobility by stabilizing agents and a beneficial use of industrial by-products. This study is an overview of data published during the last five years on the immobilization of one metalloid, As, and four heavy metals, Cr, Cu, Pb and Zn, in soils. The most extensively studied amendments for As immobilization are Fe containing materials. The immobilization of As occurs through adsorption on Fe oxides by replacing the surface hydroxyl groups with the As ions, as well as by the formation of amorphous Fe(III) arsenates and/or insoluble secondary oxidation minerals. Cr stabilization mainly deals with Cr reduction from its toxic and mobile hexavalent form Cr(VI) to stable in natural environments Cr(III). The reduction is accelerated in soil by the presence of organic matter and divalent iron. Clays, carbonates, phosphates and Fe oxides were the common amendments tested for Cu immobilization. The suggested mechanisms of Cu retention were precipitation of Cu carbonates and oxy-hydroxides, ion exchange and formation of ternary cation-anion complexes on the surface of Fe and Al oxy-hydroxides. Most of the studies on Pb stabilization were performed using various phosphorus-containing amendments, which reduce the Pb mobility by ionic exchange and precipitation of pyromorphite-type minerals. Zn can be successfully immobilized in soil by phosphorus amendments and clays.     

Toxicity potentials from waste cellular phones,and a waste management policy integrating consumer,corporate, and government responsibilities

Cellular phones have high environmental impact potentials because of their heavy metal content and current consumer attitudes toward purchasing new phones with higher functionality and neglecting to return waste phones into proper take-back systems. This study evaluates human health and ecological toxicity potentials from waste cellular phones; highlights consumer, corporate, and government responsibilities for effective waste management; and identifies key elements needed for an effective waste management strategy. The toxicity potentials are evaluated by using heavy metal content, respective characterization factors, and a pathway and impact model for heavy metals that considers end-of-life disposal in landfills or by incineration. Cancer potentials derive primarily from Pb and As; non-cancer potentials primarily from Cu and Pb; and ecotoxicity potentials primarily from Cu and Hg. These results are not completely in agreement with previous work in which leachability thresholds were the metric used to establish priority, thereby indicating the need for multiple or revised metrics. The triple bottom line of consumer, corporate, and government responsibilities is emphasized in terms of consumer attitudes, design for environment (DfE), and establishment and implementation of waste management systems including recycling streams, respectively. The key strategic elements for effective waste management include environmental taxation and a deposit-refund system to motivate consumer responsibility, which is linked and integrated with corporate and government responsibilities. The results of this study can contribute to DfE and waste management policy for cellular phones.     

Biodegradability of Thermally Aged PHB,PHB-V,and PCL in Soil Compostage

The biodegradability of poly--hydroxybutyrate (PHB), poly--hydroxybutyrate-co-valerate (PHB-V) and poly--caprolactone (PCL) were examined following thermal aging in an oven for 192, 425 and 600 h. Different temperatures, 100, 120 and 140°C for PHB and PHB-V and 30, 40 and 50^oC for PCL were used to assess the influence of this parameter on biodegradation. The biodegradability tests were done in soil compostage at pH 11.0 and involved measuring the residual mass of polymer. Thermal analysis of the polymers was done using a differential scanning calorimeter (DSC). The melting temperature and crystallinity were also determined. Thermal ageing increased the biodegradability only for PHB at 120 and 140^oC, and there was no correlation between crystallinity and the biodegradation of the polymers.     

Behavior of As,Cd, Co,Cr, Cu,Pb, Ni,and Zn at the soil/plant interface around an uncontrolled landfill (Casablanca,Morocco)

The present work undertaken in the environmental context aims to study the distribution of heavy metals in plants that grow naturally around uncontrolled landfills. The study's goal was to identify plants that can be used to remediate contaminated soils. For this purpose, 14 plants species and their rhizospheric soil samples were collected and analyzed for arsenic, cadmium, cobalt, chromium, copper, lead, nickel, and zinc by inductively coupled plasma‐atomic emission spectrometry. The results showed the presence of elevated metal concentrations in soil, many exceeding the regulatory values, and that many species exhibited an ability to accumulate multiple metals in their shoots and roots without sustaining toxicity. This was confirmed by bioconcentration and translocation factors generally higher than 1.     

Integrated Environmental and Hydraulic Design of Xerias River,Corinthos, Greece,Training Works

The modern design of flood protection and training works in cases of major natural streams and creeks, requires a fine balance between a sound engineering approach in all engineering aspects on one hand, and an environmentally acceptable solution on the other. Progress in integrating environmental and hydraulic design has been achieved over the years due to different factors, like proper collaboration of engineering disciplines, hydraulic modeling enhancement, development and use of suitable materials, amelioration of the construction methods, and proper restoration and use of the affected areas. In this paper, a synopsis of the experience that has been gained by our firm over the years in designing flood protection and river training works for urban and rural areas is presented, including the general design principles to be used as guidelines, and illustrated with the case study of river Xerias, Greece. The river Xerias is located in Peloponnese, Greece. It flows from south to north and has a catchment area of 170 km². For the last 1500 m before discharging into the Corinthian gulf, the river flows through the city of Corinthos. This is the reach, which overflowed and flooded the city during the January 1997 flood, causing a lot of damage and human life casualties.     

Tensile Strength, Elongation, Hardness, and Tensile and Flexural Moduli of PLA Filled with Glycerol-Plasticized DDGS

Rapid growth of the biofuel industry is generating large amounts of coproducts such as distillers dried grains with solubles (DDGS) from ethanol production and glycerol from biodiesel. Currently these coproducts are undervalued, but they have application in the plastics industry as property modifiers. The objective of this research effort is to quantify the effects on mechanical properties of adding DDGS and glycerol to polylactic acid (PLA). The methodology was to physically mix DDGS, as filler, with PLA pellets and injection mold the blends into test bars using glycerol as a plasticizer. The bars were subject to mechanical testing procedures to obtain tensile strength, tensile and flexural moduli, elongation to break, and surface hardness of blends from 0 to 90?%, by weight, of plasticized filler. Blends were typically relatively brittle with little or no yielding prior to fracture, and the addition of glycerol enabled molding of blends with high levels of DDGS but did not increase strength. Any presence of filler decreased the tensile strength of the PLA, and 20?C30?% filler reduced strength by 60?%. The 35?C50?% filled PLA had about one-fifth the value for pure PLA; at 60?C65?% filler level, about 10?% tensile strength remained; and over 80?% filler, 95?% of the strength was lost. Over 20?% filler, the tensile modulus decreased. The 35?% plasticized, filled blend yielded about one-half the stiffness as the pure PLA case; flexural modulus trended in the same manner but demonstrated a greater loss of stiffness. Most blends had less than 3?% elongation to break while surface hardness measurements indicated that up to 60?% filler reduced Shore D hardness by less than 20?%. The tensile strength and modulus data are consistent with the findings of other researchers and indicate that the type of filler and amount and sequence of plasticization are secondary effects, and the total PLA displaced is the dominant factor in determining the mechanical strength of the PLA and DDGS blends. Up to 65?% plasticized DDGS filler can be injection molded, and sufficient mechanical strength exists to create a variety of products. Such a novel material provides higher-value utilization of the biofuel coproducts of glycerol and DDGS and maintains the biodegradable and biocompatible nature of PLA.     

Behaviour of Cd,Cr, Mn,Ni, Pb,and Zn in sewage sludge incineration by fluidised bed furnace

Cd, Cr, Mn, Ni, Pb, and Zn behaviour during sewage sludge incineration was investigated in seven pilot tests using a circulating fluidised bed furnace. Dewatered sludge at a solids concentration of 15-18% was fed to the furnace either alone (two tests) or spiked with chlorinated organic compounds (five tests). The behaviour of metals in the fluidised bed furnace was studied by comparing metal concentrations in the two main ash streams: ash separated from the cyclone immediately following the fluidised bed furnace, and fly ash recovered in the final bag filter. A metal enrichment factor was defined as the ratio of metal concentration between filter ash and cyclone ash. Only Cd and Pb showed any significant enrichment. Their enrichment factors were mainly affected by chlorine concentration in the feed sludge. To check whether simple equilibrium models may explain and predict metal behaviour, experimental data were compared with percentage of the metal vaporisation in the combustion chamber predicted using a thermodynamic model. Discrepancies between model predictions and experimental results are accounted for by considering that kinetics may be a limiting factor in the formation of metal chloride gaseous species. Due to the very short sludge residence time in the fluidised bed furnace, the gaseous compounds have little chance to evolve completely.     

Estimation of nitrogen flow change in Beijing,China, for the years 1995, 2000, and 2004

Rapid economic growth in China has led to environmental pollution. Recycling nutrients is essential for sustainable agriculture, and it is necessary to estimate the amount of available organic resources in order to achieve this. Using nitrogen as a tracer, we estimated the organic resource flows in 1995, 2000, and 2004 in Beijing. The agricultural nitrogen flow was calculated from the fertilizer, agricultural product, and byproduct flows. The livestock nitrogen flow was calculated from the feed, excretion, and stock flows. The human nitrogen flow was calculated from the food intake, excretion, and food waste flows. The amounts of recyclable organic resources were estimated from these nitrogen flows. The Daxing, Fangshan, Miyun, Shunyi, and Tongzho areas had high nitrogen loads in 2004, as did the outer suburbs, but Beijing proper had an extremely low nitrogen flow and the inner suburbs had low nitrogen flows. The estimated amount of compost that could be produced from domestic organic waste across Beijing was equivalent to 88,100 t of nitrogen. The Beijing area contains 394,100 ha of farmland, so, if the compost was applied at an equivalent of 100 kg of nitrogen per hectare, the equivalent of 48,000 t of nitrogen would be surplus.     

A review of corn masa processing residues: generation, properties, and potential utilization

The production of corn masa-based products in the US has been increasing over the last several years, and as a result, so has the quantity of waste materials being generated from this industry. Although currently landfilled, these byproduct streams may have potential for value-added processing and utilization, which are options that simultaneously hold the promise of increased economic benefit for masa processors as well as decreased potential pollution for the environment. Fundamental to any byproduct development effort is knowledge of the characteristics of the residue stream, because physical and chemical properties are vital for the proper design of subsequent processing operations and applications. Data for masa byproduct materials are currently not readily available, however. Thus, the objective of this study was to fully investigate, review, and summarize the existing literature in order to develop a comprehensive knowledge base for these residue streams. The most substantial findings from this study were that masa residues currently are not being utilized as coproducts, but instead are being landfilled; they have a high fiber content, and thus much untapped potential exists for its extraction and value-added utilization vis-à-vis human and industrial applications, including phytosterol and ethanol production. It was also determined that masa byproducts, due to the high fiber content, may also be suitable for use as livestock feed additives, especially for ruminant animals that can digest these materials. Furthermore, due to substantial calcium content, masa byproducts could also potentially be used as a calcium resource. Under current processing practices, though, these residues have very high moisture contents. Before they can be effectively and economically utilized, they must be dehydrated in order to reduce transportation costs, decrease microbial activity, and increase shelf life.     

Health risk assessment of heavy metals (Cr, Ni, Cu, Zn, Cd, Pb) in circumjacent soil of a factory for recycling waste electrical and electronic equipment

The aim of the study was to determine the potential environmental contamination in a typical factory for recycling waste electrical and electronic equipment in Shanghai. Heavy metals (Cr, Ni, Cu, Zn, Cd, Pb) in the soil around the factory have been evaluated in this paper. Compared with the background value, the concentrations of six metals detected in all the samples were higher, which showed that toxic metals were released into soil around the factory. Compared with the Environmental Quality Standards for Soils, China grade III, all the six metals are under soil guidelines. The non-cancer risk in different directions from the factory was in the order of: the north > the west > the south > the east. For inhalation and ingestion, the non-cancer risk in the soil west of the factory was biggest. Nevertheless, the non-cancer risk in the soil north of the factory was the biggest for dermal contact. The trend of cancer risk was the west > the south > the north > the east. The non-cancer risk and the carcinogenic risk for Cr, Ni, and Cd were all below the limiting value. This study might provide a reference for the risk assessment involved in electronic waste management and recycling activities.     

Review of in situ remediation technologies for lead,zinc, and cadmium in soil

This article presents a review of in situ technologies for the remediation of soils contaminated with lead, zinc, and/or cadmium. The objective of this review is to assess the developmental status of the available in situ technologies and provide a general summary of typical applications and limitations of these technologies. The literature review identified seven in situ remediation technologies—solidification/stabilization, vitrification, electrokinetic remediation, soil flushing, phytoextraction, phytostabilization, and chemical stabilization. These technologies were considered for their ability to meet a specific set of remediation objectives under a range of conditions. Each of these technologies has both strengths and weaknesses for addressing particular remedial situations discussed in the article for each of the technologies. A general summary of which technologies are most applicable to common remedial scenarios is also provided. © 2004 Wiley Periodicals, Inc.     

CSIA of TCE and Daughter Products With Multiple Sources,Multiple Attenuation Mechanisms,and Low Ethene

One of the most often asked questions from regulators considering monitored natural attenuation (MNA) for a site is if there are mechanisms in situ that can completely detoxify the contaminant of concern. This article describes a method that uses data derived from compound‐specific isotope analysis (CSIA) to investigate if complete in situ degradation of trichloroethene (TCE) has occurred. MNA was the selected remediation strategy at the former England Air Force Base (fEAFB) in Louisiana. Previously declining concentrations of TCE, 1,2‐cis‐dichloroethene, and vinyl chloride had increased in selected wells, and less ethene was observed than expected on the basis of mass balance. Reductive dechlorination, partial or otherwise, could not explain observed trends, so the question at fEAFB had become: Was there an in situ mechanism for complete TCE detoxification (i.e., complete degradation to innocuous end products) at the site? CSIA was used for investigating this question at fEAFB. A previously developed formalism was adapted to interpret the CSIA data to answer the question. Standard interpretation assuming only reductive dechlorination demonstrated detoxification in 9 of the 15 contaminated wells, whereas the interpretation developed here did so in 14. © 2014 Wiley Periodicals, Inc.     

Bench-scale PVC swelling and rod milling of waste wire harnesses for recovery of Cu,PVC, and plasticizers

Journal of Material Cycles and Waste Management - In this study, we conducted bench-scale investigations for the recovery of Cu wires, PVC coatings, and plasticizers from long non-uniform cables by...     

Nature,frequency, and cost of environmental remediation at onshore oil and gas exploration and production sites

This article quantifies the nature, frequency, and cost of environmental remediation activities for onshore oil and gas operations, as determined from over 4,100 environmental remediation cases in Texas, Kansas, New Mexico, and Colorado. For the purpose of this article, “remediation'' refers to cleanup efforts that entail longer‐term site characterization, monitoring, and remedial action beyond the initial spill cleanup or emergency response stage. In addition, data are also presented regarding short‐term spill cleanup activities in two of the four states. © 2011 Wiley Periodicals, Inc.     

The value of composting in Germany – Economy,ecology, and legislation

Based on a recent survey of German composting plants an evaluation of costs and benefits of composting was attempted. In this regard, several economical, ecological and legal aspects and some interrelations are discussed in this paper. A special emphasis is placed on the fees and compost prices of composting plants. It is also shown how the legal framework provides the economic basis for composting in Germany, how economical and ecological costs and benefits could be assessed, and why it is so difficult to determine the value of composting.