Identification of oxidized TNT metabolites in soil samples of a former ammunition plant

Water extracts of soil samples of the former ammunition plant “Tanne” near Clausthal-Zellerfeld, Lower Saxony, Germany, were investigated for highly polar oxidized 2,4,6-trinitrotoluene (TNT) metabolites. 0.4 to 9.0 mg/kg dry soil 2,4,6-trinitrobenzoic acid (TNBA) and 5.8 to 544 mg/kg dry soil 2-amino-4,6-dinitrobenzoic acid (2-ADNBA) were found. In addition to the oxidized metabolites, TNT, 4- and 2-aminodinitrotoluene (4- and 2-ADNT), and 2,4-dinitrotoluene (2,4-DNT) were extractable with water. Most interestingly, in one sample, 2-ADNBA represented the main contaminant. The origin of the oxidized nitroaromatics is unknown at this time. They might be generated chemically or photochemically. Furthermore, a biological synthesis seems possible.     

Fiberboard plant emissions control using a silent discharge plasma

A silent discharge plasma reactor was constructed to test a potential industrial application for controlling volatile organic carbon emission from fiberboard manufacturing plants. The reactor consisted of a cylindrical single barrier dielectric barrier discharge cell connected to a high‐voltage ac power supply. Various concentrations of turpene in air were introduced into the reactor under dry and wet conditions. The destruction removal efficiencies (DRE) were monitored using a gas chromatograph mass spectrometer (GCMS) and the concentrations of carbon dioxide generated from the oxidation ofturpene were monitored using a Fourier Transform Infrared Spectrometer (FTIR). It was found that 90 percent of the turpenes could be removed at modest energy densities and that adding water to the gas mix greatly enhanced the destruction of the turpenes. However, even at high energy densities, the oxidation of turpenes did not completely form carbon dioxide. The results suggest that the Silent Discharge Plasma (SDP) system can be used to control the emission of volatile organic compounds (VOCs) from fiberboard plants, but that further testing is needed to limit the emission of carbon monoxide.     

The development and achievements of EU waste policy

While waste amounts are still growing in the EU, there is a clear shift in the waste management options employed to deal with waste. Less waste is landfilled and more is recycled or incinerated with energy recovery. In all, 62% of municipal waste was landfilled in 1995, but that figure had fallen to 40% by 2008. Waste management has a strong influence on the environment by either provoking or preventing impacts; for example, greenhouse gas emissions vary significantly between treatment options. The overall CO2-equivalent impacts from municipal waste management have in the same period been more than halved. The drivers for this change in waste management have been EU and national policies and legislation that have set up clear targets for recycling and recovery of waste. This article gives an overview of the set targets, the achieved results, and the consequences for greenhouse gas emissions of municipal waste management.     

Photodegradation of malachite green and malachite green carbinol under irradiation with different wavelength ranges

The dye malachite green (MG) is used worldwide as a fungicide in aquaculture. It is a toxic substance which in aqueous solutions is partly converted into its non-ionic colorless form (leucocarbinol). The equilibrium between these two forms is pH-dependent (pK = 6.9). To assess the photodegradation of MG under sunlight conditions, both species were irradiated separately in aqueous solutions with different pH values (4.0 and 12.0) using various ultraviolet and visible wavelength ranges (UV/VIS). A 700 W high-pressure mercury lamp with special filters was used. No artificial photooxidizers such as H₂O₂ or TiO₂ were added. MG leucocarbinol proved to be much more sensitive to irradiation than the dye form. Quantum yields Φ were calculated for some wavelength ranges as follows: MG carbinol: Φ_(280-312nm) is 4.3 × 10⁻³, Φ_(313-410nm) is 5.8 × 10⁻³, and MG dye: Φ_(280-312nm) is 4.8 × 10⁻⁵, Φ_(313-365nm) is 1.1 × 10⁻⁵, and Φ_(>365nm) is 0, respectively. Therefore, the solar photolysis of MG is an important sink and primarily depends on the photodegradation of the colorless leucocarbinol. During the irradiation of MG leucocarbinol with wavelengths >365 nm, an intermediate was formed which has photocatalytical properties.     

How do different process options and evaluation settings affect economic and environmental assessments? A case study on methyl methacrylate (MMA) production processes

We present an investigation on how economic and environmental assessment results change when different process options or evaluation settings are considered. As the main case study the production technology of methyl methacrylate (MMA) is investigated. Six commercial processes using different reaction routes are modelled and evaluated with respect to their economic and environmental performance. On these six base case models different process options and evaluation settings are considered and the resulting impacts on the assessment results are quantified. Major findings of the study are that the more decision-variables become fixed, the smaller becomes the impact of the decisions still to be taken—but not only with respect to the economic performance but also with regard to the environmental assessment result. Along the process development steps the potential impacts on the economic and environmental performance decrease to the same degree. The results obtained for the evaluation settings do not show such a systematic pattern as those for the process options. This finding indicates that decision makers face many options in the economic and especially the environmental assessment of chemical processes which might lead to quite different magnitudes in variability due to either the choice of method or the choice of method parameters. This paper demonstrates that the resulting variability might be crucial with respect to the decision making outcome.     

Reducing Meat Consumption in Today’s Consumer Society: Questioning the Citizen-Consumer Gap

Our growing demand for meat and dairy food products is unsustainable. It is hard to imagine that this global issue can be solved solely by more efficient technologies. Lowering our meat consumption seems inescapable. Yet, the question is whether modern consumers can be considered as reliable allies to achieve this shift in meat consumption pattern. Is there not a yawning gap between our responsible intentions as citizens and our hedonic desires as consumers? We will argue that consumers can and should be considered as partners that must be involved in realizing new ways of protein consumption that contribute to a more sustainable world. In particular the large food consumer group of flexitarians offer promising opportunities for transforming our meat consumption patterns. We propose a pragmatic approach that explicitly goes beyond the standard suggestion of persuasion strategies and suggests different routes of change, coined sustainability by stealth, moderate involvement, and cultural change respectively. The recognition of more routes of change to a more plant-based diet implies that the ethical debate on meat should not only associate consumer change with rational persuasion strategies and food citizens that instantiate “strong” sustainable consumption. Such a focus narrows the debate on sustainable protein consumption and easily results in disappointment about consumers’ participation. A more wide-ranging concept of ethical consumption can leave the negative verdict behind that consumers are mainly an obstacle for sustainability and lead to a more optimistic view on modern consumers as allies and agents of change.     

The effects of biochars from rice residue on the formation of iron plaque and the accumulation of Cd, Zn, Pb, As in rice (Oryza sativa L.) seedlings

A historically multi-metal contaminated soil was amended with biochars produced from different parts of rice plants (straw, husk and bran) to investigate how biochar can influence the mobility of Cd, Zn, Pb and As in rice seedlings (Oryza sativa L.). Rice shoot concentrations of Cd, Zn and Pb decreased by up to 98%, 83% and 72%, respectively, due to biochar amendment, though that of As increased by up to 327%. Biochar amendments significantly decreased pore water concentrations (C_pw) of Cd and Zn and increased that of As. For Pb it depended on the amendment. Porewater pH, dissolved organic carbon, dissolved phosphorus, silicon in pore water and iron plaque formation on root surfaces all increased significantly after the amendments. The proportions of Cd and Pb in iron plaque increased by factors 1.8-5.7 and 1.4-2.8, respectively; no increase was observed for As and Zn. Straw-char application significantly and noticeably decreased the plant transfer coefficients of Cd and Pb. This study, the first to investigate changes in metal mobility and iron plaque formation in rice plants due to amending a historically contaminated soil with biochar, indicates that biochar has a potential to decrease Cd, Zn and Pb accumulations in rice shoot but increase that of As. The main cause is likely biochar decreasing the C_pw of Cd and Zn, increasing the C_pw of As, and increasing the iron plaque blocking capacity for Cd and Pb.     

Adsorption of mono- and di-butyltin by a wheat charcoal: pH effects and modeling

Understanding adsorption processes of butyltins (BTs) such as monobutyltin (MBT) and dibutyltin (DBT) by black carbons is important for the evaluation of BT exposure risks to organisms and humans. However, relevant knowledge is scarce. In this study, the acidity constants pK_a,1 = 2.3, pK_a,2 = 3.5 and pK_a,3 = 5.9 for MBT and pK_a,1 = 3.0 and pK_a,2 = 5.1 for DBT are estimated via potentiometric titration. Additionally, adsorption isotherms of BTs to a wheat charcoal were determined. The adsorption behavior was observed to be pH-dependent due to BT speciation and the pH-dependent surface charge of the charcoal. MBT adsorption to the charcoal decreases with increasing pH from 4 to 8, while the highest adsorption occurs at pH 6 for DBT. Adsorption of the BTs is successfully described in the pH range of 3-10 by using a newly developed pH-dependent Dual Langmuir model. The model has the potential to predict the interaction of BT species with charcoal, which can contribute to the risk assessments of BTs in the environment.     

Diversity and distribution of riparian plant communities in relation to stream size and eutrophication

The present study was conducted in 47 different riparian areas distributed throughout Denmark to investigate diversity and distributional patterns of plant communities along a lowland stream size gradient (first to fifth order). The investigated areas were representative for Danish riparian areas not in use for agricultural production. We investigated plant community richness along a stream size gradient and the influence of eutrophication on the abundance of different plant communities. Vegetation analyses were performed in transects placed perpendicular to the stream channel, with a total of 1798 plots analyzed. Overall, we found a positive relationship between stream mean depth as a measure of stream size and the number of plant community types identified in the riparian areas. We also found that the abundance of the identified communities was positively correlated with their nutrient preference and negatively correlated with their moisture preference. The abundance of alkaline fens and Molinia meadows (protected community types) in riparian areas decreased with increasing size of the stream, whereas the abundance of humid meadows and wet herb fringes increased with increasing size of the stream. Based on our findings, we recommend that wide buffer zones be established along streams with protected habitat types in the associated riparian areas to reduce the direct impact from agriculture. Furthermore, we recommend that wide buffer zones be established along middle-sized and large streams because several community types may develop.