Characterization of composites based on expanded polystyrene wastes and wood flour

This paper aims to evaluate the potential for the use of recycled expanded polystyrene and wood flour as materials for the development of wood plastic composites. The effects of wood flour loading and coupling agent addition on the mechanical properties and morphology of wood thermoplastic composites were examined. In addition, a methodology for the thermo-mechanical recycling of expanded polystyrene waste was developed. The results show that the mechanical properties decreased as the wood flour loading increased. On the other hand, the use of poly(styrene-co-maleic anhydride), SMA, as a coupling agent improved the compatibility between the wood flour and polystyrene matrix and the mechanical properties subsequently improved. A morphological study revealed the positive effect of the coupling agent on the interfacial bonding. The density values obtained for the composites were compared with the theoretical values and showed agreement with the rule of mixtures. Based on the findings of this work, it appears that both recycled materials can be used to manufacture composites with high mechanical properties and low density.     

Organochlorine concentrations in franciscana dolphins, Pontoporia blainvillei, from Brazilian waters

Blubber samples were collected from ten franciscana dolphins either incidentally captured in fishing operations or stranded on São Paulo (SP) and Paraná (PR) states littoral, Southeastern and Southern Brazilian coast, respectively. Determination of PCB, DDT and HCB concentrations were performed by capillary gas chromatograph coupled to electron capture detector (ECD). ΣDDT, ΣPCB and HCB concentrations ranged from 264 ng g⁻¹ to 5811 ng g⁻¹ lipid, from 909 ng g⁻¹ to 5849 ng g⁻¹ lipid and from 10 ng g⁻¹ to 61 ng g⁻¹ lipid, respectively. Regarding DDTs, the distribution of the mean percentages decreased in the following order: p,p′-DDE > p,p′-DDD > p,p′-DDT. The ΣDDT/ΣPCB ratio varied between 0.27 and 0.42 in Northern and Central SP coast, while in Southern SP and PR coast the values were 1.6 and 1.9, respectively. Dissimilarities in ΣDDT/ΣPCB ratios point to different sources of organochlorine compounds to franciscana dolphins in the study area. Considering the endocrine disruptive action of organochlorine compounds, the concentrations found in franciscana dolphins from Brazilian waters may represent an additional obstacle to the conservation of this endangered cetacean species.     

Quality considerations of European PM emission inventories

This paper reviews information on emission inventories of particulate matter (PM) in Europe. A large body of scientific literature is available to cover many different aspects. Studies focus on specific sources or source sectors (road transport as well as off-road machinery, domestic heating, industry, agriculture, and natural sources), among which especially road transport emissions are clearly best established. Emission inventories comprising all sources are available for specific European regions, often pointing out regional differences, but also for the entire continent. Still these inventories often are not able to satisfy the needs. Due to PM specific circumstances such as the large number of sources, very different release pathways and differences of the individual particles in terms of chemical composition or size, it is very difficult to appropriately handle measurement conditions to arrive at adequate emission factors, especially when emission points cannot be defined clearly. Information on fugitive emissions (caused by wind shear, material transfer processes or other mechanical forces from non-point sources) is sparse, except for road traffic emissions where recent data seems to converge. The problem of data gaps concerns activities in industry (quarries), agriculture, but also natural particles like sea salt and wind-blown dust. Comparing complete inventories to independent efforts in assessing emissions, e.g. atmospheric measurements combined with source apportionment, allows to better understand and quantify the reliability of inventory data. Methodological improvements and harmonization currently under way in Europe will focus efforts and allow for more reliable PM inventories in the near future.     

An international comparative study of end-of-life vehicle (ELV) recycling systems

End-of-life vehicles (ELV) have become a global concern as automobiles have become popular worldwide. An international workshop was held to gather data and to discuss 3R policies and ELV recycling systems, their background and present situation, outcomes of related policies and programs, the framework of recycling and waste management, and case studies on related topics in several countries and regions, as well as the essential points of the comparison. Legislative ELV recycling systems are established in the EU, Japan, Korea, and China, while in the US, ELV recycling is managed under existing laws on environmental protection. Since automobile shredding residue (ASR) has a high calorific value and ash content, and includes heavy metals as well as a mass of unclassified fine particles, recycling ASR is considered highly difficult. Countries with a legislative ELV system commonly set a target for recovery rates, with many aiming for more than 95 % recovery. In order to reach this target, higher efficiency in ASR recovery is needed, in addition to material recycling of collectable components and metals. Environmentally friendly design was considered necessary at the planning and manufacturing stages, and the development of recycling systems and techniques in line with these changes are required for sound ELV management.     

Investigating the real-world emission characteristics of light-duty gasoline vehicles and their relationship to local socioeconomic conditions in three communities in Los Angeles,California

This paper discusses results from a vehicular emissions research study of over 350 vehicles conducted in three communities in Los Angeles, CA, in 2010 using vehicle chase measurements. The study explores the real-world emission behavior of light-duty gasoline vehicles, characterizes real-world super-emitters in the different regions, and investigates the relationship of on-road vehicle emissions with the socioeconomic status (SES) of the region. The study found that in comparison to a 2007 earlier study in a neighboring community, vehicle emissions for all measured pollutants had experienced a significant reduction over the years, with oxides of nitrogen (NO_X) and black carbon (BC) emissions showing the largest reductions. Mean emission factors of the sampled vehicles in low-SES communities were roughly 2–3 times higher for NO_X, BC, carbon monoxide, and ultrafine particles, and 4–11 times greater for fine particulate matter (PM_2.5) than for vehicles in the high-SES neighborhood. Further analysis indicated that the emission factors of vehicles within a technology group were also higher in low-SES communities compared to similar vehicles in the high-SES community, suggesting that vehicle age alone did not explain the higher vehicular emission in low-SES communities.

Evaluation of the emission factor distribution found that emissions from 12% of the sampled vehicles were greater than five times the mean from all of the sampled fleet, and these vehicles were consequently categorized as “real-world super-emitters.” Low-SES communities had approximately twice as many super-emitters for most of the pollutants as compared to the high-SES community. Vehicle emissions calculated using model-year-specific average fuel consumption assumptions suggested that approximately 5% of the sampled vehicles accounted for nearly half of the total CO, PM_2.5, and UFP emissions, and 15% of the vehicles were responsible for more than half of the total NO_X and BC emissions from the vehicles sampled during the study.

Implications: This study evaluated the real-world emission behavior and super-emitter distribution of light-duty gasoline vehicles in California, and investigated the relationship of on-road vehicle emissions with local socioeconomic conditions. The study observed a significant reduction in vehicle emissions for all measured pollutants when compared to an earlier study in Wilmington, CA, and found a higher prevalence of high-emitting vehicles in low-socioeconomic-status communities. As overall fleet emissions decrease from stringent vehicle emission regulations, a small fraction of the fleet may contribute to a disproportionate share of the overall on-road vehicle emissions. Therefore, this work will have important implications for improving air quality and public health, especially in low-SES communities.     

Solubility and adsorption behaviors of chlorpyriphos-methyl in the presence of surfactants

In the present work changes in the adsorption of the pesticide chlorpyrifos-methyl (CLP-m) on soil colloids induced by application of surfactants were determined using a batch equilibrium method. The surfactants used were sodium dodecyl sulphate (SDS), Tween 20, and dihexadecyldimethylammonium bromide (DHAB). The adsorption isotherms of CLP-m in aqueous medium and in surfactant solutions at concentration equal to the critical micelle concentration (CMC) fitted the Freunlich adsorption equation generally with R² values greater than 0.96. While the addition of SDS and DHAB decreased the pesticide adsorption, the addition of Tween 20 increased the pesticide adsorption. The increases or decreases in the adsorption in the experiment revealed that the behavior of CLP-m in soil water-systems mainly depends on the type of surfactant. Moreover water solubility of CLP-m changes by the three surfactants below and above their CMC were studied. While the solubility of CLP-m was enhanced by SDS both below and above the CMC, the solubility of the pesticide was enhanced by DHAB only above the CMC. Tween 20 did not influence the solubility of CLP-m.     

The influence of copper on tebuconazole sorption onto soils, humic substances, and ferrihydrite

The aim of this study is to investigate how the presence of Cu influences tebuconazole (Teb) sorption onto contrasting soil types and two important constituents of the soil sorption complex: hydrated Fe oxide and humic substances. Tebuconazole was used in commercial form and as an analytical-grade chemical at different Teb/Cu molar ratios (1:4, 1:1, 4:1, and Teb alone). Increased Cu concentrations had a positive effect on tebuconazole sorption onto most soils and humic substances, probably as a result of Cu?Teb tertiary complexes on the soil surfaces. Tebuconazole sorption increased in the following order of different Teb/Cu ratios 1:4?>?1:1?>?4:1?>?without Cu addition, with the only exception for the Leptosol and ferrihydrite. The highest K _f value was observed for humic substances followed by ferrihydrite, the Cambisol, the Arenosol, and the Leptosol. The sorption of analytical-grade tebuconazole onto all matrices was lower, but the addition of Cu supported again tebuconazole sorption. The Teb/Cu ratio with the highest Cu addition (1:4) exhibited the highest K _f values in all matrices with the exception of ferrihydrite. The differences in tebuconazole sorption can be attributed to the additives present in the commercial product. This work proved the importance of soil characteristics and composition of the commercially available pesticides together with the presence of Cu on the behavior of tebuconazole in soils.     

Anaerobic Mesophilic Treatment of Cattle Manure in an Upflow Anaerobic Sludge Blanket Reactor with Prior Pasteurization

Abstract

Different autonomous communities located in northern Spain have large populations of dairy cattle. In the case of Asturias, the greatest concentration of dairy farms is found in the areas near the coast, where the elimination of cattle manure by means of its use as a fertilizer may lead to environmental problems. The aim of the present research work was to study the anaerobic treatment of the liquid fraction of cattle manure at mesophilic temperature using an upflow anaerobic sludge blanket (UASB) reactor combined with a settler after a pasteurization process at 70 °C for 2 hr. The manure used in this study came from two different farms, with 40 and 200 cows, respectively. The manure from the smaller farm was pretreated in the laboratory by filtration through a 1-mm mesh, and the manure from the other farm was pretreated on the farm by filtration through a separator screw press (0.5-mm mesh). The pasteurization process removed the pathogenic microorganisms lacking spores, such as Enterococcus, Yersinia, Pseudomonas, and coliforms, but bacterial spores are only reduced by this treatment, not removed. The combination of a UASB reactor and a settler proved to be effective for the treatment of cattle manure. In spite of the variation in the organic loading rate and total solids in the influent during the experiment, the chemical oxygen demand (COD) of the effluent from the settler remained relatively constant, obtaining reductions in the COD of ～85%.     

Metabolism of the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in a contaminated vadose zone

The aim of this study was to explore biodegradation potential of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in a deep contaminated unsaturated zone over Israel's coastal aquifer. While anaerobic biodegradation potential was observed throughout the profile down to the water table at a depth of 45 m, aerobic biodegradation was limited to the surface of the unsaturated zone. Traces of nitroso-RDX intermediates were detected in the soil samples, indicating possible in situ activity. Polymerase chain reaction and denaturing gradient gel electrophoresis analysis revealed that the microbial population in the soil consisted of protobacteria, but no known RDX degraders were detected. However, a 16S rRNA gene sequence most similar to Sphingomonas sp. was detected at all depths. Biodegradation rates were faster in the surface (0 and 1m) versus deeper soil samples (22 and 45 m) and were not affected under anaerobic conditions by the presence of nitrate, indicating a concurrent reduction of both compounds. RDX half-life in the surface soil was mostly dependent on carbon content and to lesser extent on soil moisture. Biomineralization of RDX to CO(2) was confirmed by incubating surface soil with (14)C-labeled RDX. An aerobic RDX-degrading bacterium, identified as Gordonia sp., was isolated from the soil: it degraded RDX aerobically and produced 4-nitro-2,4-diazabutanal. This study, the first to explore RDX biodegradation in the deep vadoze zone, indicates biodegradation potential throughout the profile, which is likely to support natural attenuation.     

Trace element accumulation in woody plants of the Guadiamar Valley, SW Spain: a large-scale phytomanagement case study

Phytomanagement employs vegetation and soil amendments to reduce the environmental risk posed by contaminated sites. We investigated the distribution of trace elements in soils and woody plants from a large phytomanaged site, the Guadiamar Valley (SW Spain), 7 years after a mine spill, which contaminated the area in 1998. At spill-affected sites, topsoils (0-25 cm) had elevated concentrations of As (129 mg kg(-1)), Bi (1.64 mg kg(-1)), Cd (1.44 mg kg(-1)), Cu (115 mg kg(-1)), Pb (210 mg kg(-1)), Sb (13.8 mg kg(-1)), Tl (1.17 mg kg(-1)) and Zn (457 mg kg(-1)). Trace element concentrations in the studied species were, on average, within the normal ranges for higher plants. An exception was white poplar (Populus alba), which accumulated Cd and Zn in leaves up to 3 and 410 mg kg(-1) respectively. We discuss the results with regard to the phytomanagement of trace element contaminated sites.