Phototransformation of Alphacypermethrin as Thin Film on Glass and Soil Surface∗

Photodegradation of alphacypermethrin ((RS)-α cyano-3-phenoxy benzyl (1RS) cis-3-(2,2,dichlorovinyl)-2,2-dimethyl cyclopropane carboxylate) was studied as a thin film on glass surface and on black and red soil surfaces. A number of photoproducts from glass surfaces have been isolated, characterized and identified by gas chromatography-mass spectroscopy (GC-MS). However, only two of them viz. 3-phenoxy benzyl alcohol and [2,2-dichlorovinyl-3(2,2,dimethyl) cyclopropane carboxylate] could be identified from both the soil. Rate of photodegradation on glass and soil surface under UV and sunlight followed first order kinetics with significant correlation coefficients. The rate of photodegradation was greater on black than on red soil.

     

Variations of anthropogenic CO2 in urban area deduced by radiocarbon concentration in modern tree rings

Radiocarbon concentration in the atmosphere is significantly lower in areas where man-made emissions of carbon dioxide occur. This phenomenon is known as Suess effect, and is caused by the contamination of clean air with non-radioactive carbon from fossil fuel combustion. The effect is more strongly observed in industrial and densely populated urban areas. Measurements of carbon isotope concentrations in a study area can be compared to those from areas of clear air in order to estimate the amount of carbon dioxide emission from fossil fuel combustion by using a simple mathematical model. This can be calculated using the simple mathematical model. The result of the mathematical model followed in this study suggests that the use of annual rings of trees to obtain the secular variations of ¹⁴C concentration of atmospheric CO₂ can be useful and efficient for environmental monitoring and modeling of the carbon distribution in local scale.     

The elephant in the room – A comparative study of uncertainties in carbon offsets

The clean development mechanism (CDM) is a flexible mechanism under the Kyoto Protocol, which makes it possible for developed countries to offset their emissions of greenhouse gases through investing in climate change mitigation projects in developing countries. When the mitigation benefit of a CDM project is quantified, measurable uncertainties arise that can be minimised using established statistical methods. In addition, some unmeasurable uncertainties arise, such as the rebound effect of demand-side energy efficiency projects. Many project types related to land use, land-use change and forestry (LULUCF) have been excluded from the CDM in part because of the high degree of statistical uncertainty in measurements of the carbon sink and risk of non-permanence. However, recent discussions within the United Nations Framework Convention on Climate Change (UNFCCC) have opened up for the possibility of including more LULUCF activities in the future. In the light of this discussion, we highlight different aspects of uncertainties in LULUCF projects (e.g. the risk of non-permanence and the size of the carbon sink) in relation to other CDM project categories such as renewables and demand-side energy efficiency. We quantify the uncertainties, compare the magnitudes of the uncertainties in different project categories and conclude that uncertainties could be just as significant in CDM project categories such as renewables as in LULUCF projects. The CDM is a useful way of including and engaging developing countries in climate change mitigation and could be a good source of financial support for LULUCF mitigation activities. Given their enormous mitigation potential, we argue that additional LULUCF activities should be included in the CDM and other future climate policy instruments. Furthermore, we note that Nationally Appropriate Mitigation Actions (NAMAs) are currently being submitted to the UNFCCC by developing countries. Unfortunately, the under-representation of LULUCF in comparison to its potential is evident in the NAMAs submitted so far, just as it has been in the CDM. Capacity building under the CDM may influence NAMAs and there is a risk of transferring the view on uncertainties to NAMAs.     

Evaluation of municipal solid waste composting kinetics

Most modern municipal solid waste (MSW) composting operations have emphasized the enhancement of decomposition of the organic fraction of the waste to comply with strict environmental regulations. This can be achieved once the composting process kinetics are well understood. This study examined process kinetics through experimentation with bench-scale reactors under controlled composting conditions to show the interdependence between biological, chemical and physical factors during composting of MSW. The effects of temperature, moisture content, waste particle size and carbon to nitrogen (C/N) ratio on process kinetics were evaluated. The results obtained revealed that these factors should be carefully controlled in order to achieve optimum process performance. It has been found that the organic matter degradation during composting follows a first-order kinetic model.     

Water and carbon fluxes above European coniferous forests modelled with artificial neural networks

Artificial neural networks are used to select a minimal set of input variables to model water vapour and carbon exchange of coniferous forest ecosystems, independently of tree species and without detailed physiological information. Neural networks are used because of their power to fit highly non-linear relations between input and output-variables. Radiation, temperature, vapour pressure deficit and time of the day showed to be the dynamic input variables that determine ecosystem water fluxes. The same variables, together with projected leaf area index are needed for modelling CO₂-fluxes. The results for the individual sites show that the neural networks found mean water and carbon flux responses to the driving variables valid for all sites. The sensitivity analysis of the derived neural networks shows that the LAI-effect of the CO₂-flux model is overfitted because of the low variability of LAI. However, the predictions of CO₂-fluxes of sites not included in the calibration set indicate that the LAI-response of the network is reliable and that results can be used as a first estimate of the net ecosystem carbon exchange of the forest sites. Independent predictions of forest ecosystem vapour fluxes were equally satisfying as empirical models specifically calibrated for the individual sites. The results indicate that both short term water and carbon fluxes of European coniferous forests can be modelled without using detailed physiological and site specific information.     

BVOC emissions, photosynthetic characteristics and changes in chloroplast ultrastructure of Platanus orientalis L. exposed to elevated CO2 and high temperature

To investigate the interactive effects of increasing [CO₂] and heat wave occurrence on isoprene (IE) and methanol (ME) emissions, Platanus orientalis was grown for one month in ambient (380 μmol mol⁻¹) or elevated (800 μmol mol⁻¹) [CO₂] and exposed to high temperature (HT) (38 °C/4 h). In pre-existing leaves, IE emissions were always higher but ME emissions lower as compared to newly-emerged leaves. They were both stimulated by HT. Elevated [CO₂] significantly reduced IE in both leaf types, whereas it increased ME in newly-emerged leaves only. In newly-emerged leaves, elevated [CO₂] decreased photosynthesis and altered the chloroplast ultrastructure and membrane integrity. These harmful effects were amplified by HT. HT did not cause any unfavorable effects in pre-existing leaves, which were characterized by inherently higher IE rates. We conclude that: (1) these results further prove the isoprene's putative thermo-protective role of membranes; (2) HT may likely outweigh the inhibitory effects of elevated [CO₂] on IE in the future.     

Does nitrogen deposition increase forest production? The role of phosphorus

Effects of elevated N deposition on forest aboveground biomass were evaluated using long-term data from N addition experiments and from forest observation plots in Switzerland. N addition experiments with saplings were established both on calcareous and on acidic soils, in 3 plots with Fagus sylvatica and in 4 plots with Picea abies. The treatments were conducted during 15 years and consisted of additions of dry NH₄NO₃ at rates of 0, 10, 20, 40, 80, and 160 kg N ha⁻¹ yr⁻¹. The same tree species were observed in permanent forest observation plots covering the time span between 1984 and 2007, at modeled N deposition rates of 12-46 kg N ha⁻¹ yr⁻¹. Experimental N addition resulted in either no change or in a decreased shoot growth and in a reduced phosphorus concentration in the foliage in all experimental plots. In the forest, a decrease of foliar P concentration was observed between 1984 and 2007, resulting in insufficient concentrations in 71% and 67% of the Fagus and Picea plots, respectively, and in an increasing N:P ratio in Fagus. Stem increment decreased during the observation period even if corrected for age. Forest observations suggest an increasing P limitation in Swiss forests especially in Fagus which is accompanied by a growth decrease whereas the N addition experiments support the hypothesis that elevated N deposition is an important cause for this development.     

An LCA model for waste incineration enhanced with new technologies for metal recovery and application to the case of Switzerland

A process model of municipal solid waste incinerators (MSWIs) and new technologies for metal recovery from combustion residues was developed. The environmental impact is modeled as a function of waste composition as well as waste treatment and material recovery technologies. The model includes combustion with a grate incinerator, several flue gas treatment technologies, electricity and steam production from waste heat recovery, metal recovery from slag and fly ash, and landfilling of residues and can be tailored to specific plants and sites (software tools can be downloaded free of charge). Application of the model to Switzerland shows that the treatment of one tonne of municipal solid waste results on average in 425 kg CO₂-eq. generated in the incineration process, and 54 kg CO₂-eq. accrue in upstream processes such as waste transport and the production of operating materials. Downstream processes, i.e. residue disposal, generates 5 kg CO₂-eq. Savings from energy recovery are in the range of 67 to 752 kg CO₂-eq. depending on the assumptions regarding the substituted energy production, while the recovery of metals from slag and fly ash currently results in a net saving of approximately 35 kg CO₂-eq. A similar impact pattern is observed when assessing the MSWI model for aggregated environmental impacts (ReCiPe) and for non-renewable resource consumption (cumulative exergy demand), except that direct emissions have less and no relevance, respectively, on the total score. The study illustrates that MSWI plants can be an important element of industrial ecology as they provide waste disposal services and can help to close material and energetic cycles.     

Theoretical analysis of change in forest carbon use efficiency with stand development: A case study on Hinoki Cypress (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.) plantation from the seedling stage

Changes in carbon use efficiency (CUE), which is defined as the ratio of net primary production (NPP) to gross primary production (GPP), were estimated for the aerial parts of the Hinoki Cypress (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.) with respect to stand development. The analysis incorporated previously published data from the early stages of stand development, namely the seedling stages of the cypress. For this analysis, a simple mathematical model to assess the changes in CUE was developed by incorporating data on physiological variables and mass of woody species. The CUE tended to increase with increases in the aboveground biomass of the stand, and then decreased gradually despite increases in the aboveground biomass. The CUE-value (0.28, 0.39) of the seedling stage was lower than that (0.33-0.58) of the young or mature trees. To examine the effect of physiological variables and mass on CUE, the ratios of the specific respiration rate to the specific photosynthetic rate (r/a) and the leaf biomass to the aboveground biomass or leaf mass ratio (y_L/y_T) were calculated. The low value of CUE at the seedling stage was due to the high ratio of specific respiration rate to specific photosynthetic rate r/a, but was not due to the high value of the leaf mass ratio y_L/y_T. In addition, the decline in CUE associated with older stages of stand development was due to the decreasing changes in y_L/y_T, and the r/a ratio did not influence the change in CUE.     

Effects of ultrasonic treatment on dithiothreitol (DTT) assay measurements for carbon materials

The dithiothreitol (DTT) assay is the most commonly used method to quantify the oxidative potential of fine particles. However, the reported DTT decay rates of carbon black (CB) materials vary greatly among different researchers. This might have resulted from either the intrinsic toxicity of CB or the unsuitability of the DTT assay protocol for CB particles. In the current study, the protocol of the DTT assay for CB materials has been carefully evaluated. It was found that the dispersion degree of CB particles in water has a great influence on the DTT decay rate of CB materials. For CB particles (special black 4A (SB4A) and Printex U) and single-walled carbon nanotube tube (SWCNT), the DTT decay rate after sonication for 10?min became 4.2, 4.6 and 1.7 times higher than that without sonication. The rate continued to grow as a function of ultrasound time up to 30?min of sonication. Although the concentration of soluble transition metals and surface oxygen-containing species such as carbonyls increased slightly with sonication, they had no significant effects on the measured DTT activity, while the increase in the dispersion degree of aggregates was found to play a vital role in the observed enhancement of the DTT decay rates for different CB materials. Based on our results, 30?min of sonication is recommended for sample dispersion when measuring the DTT decay rate of CB materials.