Evaluation of recycling policies for PET bottles based on multiattribute utility indices

This study focused on waste plastic, especially the polyethylene telephthalate (PET) bottle as representative waste, which has been assigned as goods to be recycled by the Packaging Waste Recycling Law in Japan. We developed a plastic transport model which explained the entire flow of plastic from the production stage to the disposal stage within an the evaluation model of plastic recycle policy based on multiattribute utility theory. This model is designed to be used by local municipal governments in supporting the evaluation of the PET bottle recycling policy. In evaluating the plastics recycling policy, we selected indices relating to economy, ecology, and rate of resource recycling. The results indicate that when the evaluation of the material recycling policy and thermal recycling policy in the model city were characterized in terms of their economic and environmental aspects the thermal recycling policy had the highest utility within our scenario. Received: July 31, 1998 / Accepted: January 26, 1999     

Estrogen equivalent concentration of 13 branched para-nonylphenols in three technical mixtures by isomer-specific determination using their synthetic standards in SIM mode with GC-MS and two new diasteromeric isomers

Thirteen isomers of branched para-nonylphenols (para-NP) in three technical mixtures were isomer-specifically determined using their synthesized standards by SIM of structurally specific ions, m/z 135, 149 or 163 with GC–MS. Of the 13 isomers, four isomers, 4-(2,4-dimethylheptan-4-yl)phenol, 4-(4-methyloctan-4-yl)phenol, 4-(3-ethyl-2-methylhexan-2-yl)phenol (3E22NP) and 4-(2,3-dimethylheptan-2-yl)phenol synthesized for their determinations were first used as standard substances. The 13 isomers in the technical mixtures individually occurred at mass percent portion of more than 2%. The total mass percent portions in the mixtures from Tokyo Chemical Industry (TCI), Aldrich, and Fluka covered with 89 ± 2%, 75 ± 4% and 77 ± 2%, respectively. The abundance of 4-(3,6-dimethylheptan-3-yl)phenol in the three mixtures was the largest with 11.1 ± 2% to 9.9 ± 0.3%, while that of 4-(2-methyloctan-2-yl)phenol was the smallest with 2.9 ± 0.3% to 3.0 ± 0.2%. Additionally, structures of four new isomers of more than 1% portion present in a technical mixture were elucidated as two pairs of diastereomeric isomers: two types of 4-(3,4-dimethylheptan-4-yl)phenol (344NP) and those of 4-(3,4-dimethylheptan-3-yl)phenol (343NP). By estrogenic assay of 13 isomers with yeast estrogen screen system, the activity of 3E22NP was the highest, while that of 4-(3-methyloctan-3-yl)phenol was the least. Their relative activities to that of 3E22NP were individually calculated. Estrogenic equivalent concentrations of the three technical mixtures were predictively evaluated. The ratio of the EEC to the conventional concentration, total mass percent portions of the 13 isomers in technical mixtures were 0.208 for TCI, 0.206 for Aldrich and 0.205 for Fluka. The predicted estrogenic activity of measured concentration of para-NP in technical mixtures was approximately 5-fold greater than the measured estrogen agonist activity.     

Field validation of an active sampling cartridge as a passive sampler for long-term carbonyl monitoring

A carbonyl sampler originally designed for the active sampling method (Sep-Pak XPoSure) was used for long-term passive sampling, and its applicability as a passive sampler was examined through field experiments. The uptake rates of passive sampling were determined experimentally from collocated passive and active samplings for various sampling periods. The obtained uptake rates of formaldehyde, acetaldehyde, and acetone were 1.48, 1.23, and 1.08 mL/min, respectively. These uptake rates were consistent for a wide range of the sampling term (12 hr-2 weeks). Uptake rates of each carbonyl were proportional to the diffusion coefficients of each. Therefore, the ratios of diffusion coefficients were used to calculate the uptake rates of carbonyls for which the rates were not determined experimentally. Lower limits of determination were 2.16-17.5 microg/m3 for 2-week sampling. It was confirmed that 2-week monitoring of carbonyl concentrations up to 118-229 microg/m3 was possible. Relative standard deviations of the passive method generated from the repeatability test were 2-12.3% error for five samplings, and the recovery efficiencies were larger than 90%. Thus, the passive sampler was found to be highly suitable for long-term monitoring of carbonyl compounds.     

Measurements of aerosol optical properties in central Tokyo during summertime using cavity ring-down spectroscopy: Comparison with conventional techniques

A highly sensitive cavity ring-down spectrometer (CRDS) was used to monitor the aerosol extinction coefficient at 532 nm. The performance of the spectrometer was evaluated using measurements of nearly monodisperse polystyrene particles with diameters between 150 and 500 nm. By comparing the observed results with those determined using Mie theory, the accuracy of the CRDS instrument was determined to be >97%, while the upper limit for the precision of the instrument was estimated to be 0.6–3.5% (typically 2%), depending on the particle number concentration, which was in the range of 30–2300 particles cm^?3. Simultaneous measurements of the extinction (b_ext), scattering (b_sca) and absorption (b_abs) coefficients of ambient aerosols were performed in central Tokyo from 14 August to 2 September 2007 using the CRDS instrument, two nephelometers and a particle/soot absorption photometer (PSAP), respectively. The value of b_ext measured using the CRDS instrument was compared with the sum of the b_sca and b_abs values measured with a nephelometer and a PSAP, respectively. Good agreement between the b_ext and b_sca + b_abs values was obtained except for data on days when high ozone mixing ratios (>130 ppbv) were observed. During the high-O₃ days, the values for b_sca + b_abs were ～7% larger than the value for b_ext, possibly because the value for b_abs measured by the PSAP was overestimated due to interference from coexisting non-absorbing aerosols such as secondary organic aerosols.     

A GIS-based zoning of illegal dumping potential for efficient surveillance

To assist in the efficient surveillance against illegal dumping, this study examined and evaluated two methods to illustrate the illegal dumping potential of sites using GIS (Geographic Information System) data. One approach focused on the occurrence of illegal dumping sites; the other on the size of the illegal dumping. Both approaches to zoning were implemented for the Kanto region of Japan, utilizing seven or eight major geographical attributes most closely related to illegal dumping. The zoning results revealed the areas requiring patrols against illegal dumping. Evaluation of the zoning results using the ROC (Receiver Operating Characteristic) curve showed the number of illegal dumping sites detectable under certain surveillance conditions and that the size-based zoning was superior, but this superiority was insignificant for revealing sites with higher potential for large illegal dumping, for which it would be sufficient to use the occurrence-based zoning. The evaluation also showed the contribution of each geographical attribute. Finally, application of the ROC curve to the surveillance planning process was examined, which enables the total social cost of pollution by illegal dumping, rehabilitation of dumping sites, and illegal dumping surveillance to be minimized.     

Characteristics of dioxin emissions at startup and shutdown of MSW incinerators

Dioxin concentrations from municipal waste incinerators in Japan and elsewhere often show low concentrations that comply with legal limits (in this paper, the term "dioxin" designates WHO-TEQ: PCDD/Fs+dioxin-like PCB). However, such data is usually generated under normal steady state operational conditions, and there has been little investigation of releases occurring during startup and shutdown. It is important, therefore, to ascertain quantitatively emissions in an unsteady state (startup and shutdown) in order to correctly evaluate the relationship between emissions from a facility and the surrounding environment. The present study aimed to examine dioxin emissions of a continuously operated incinerator at startup and shutdown, and estimating the time period of greatest emission, and the processes causing dioxin generation. The startup process was divided into five stages and the shutdown into two; at each stage, dioxins in the flue gas were measured at the boiler outlet and the stack. From the concentration of dioxins and the flue gas volume at each stage, the amount of dioxins at startup and shutdown were calculated, and these were compared with that under steady state conditions. Dioxin concentration at the stack under steady state conditions was a very low level, while those at startup and shutdown were higher. In the case where dioxin concentration under a steady state is a low level like in this study, it is indicated that the total annual dioxin emission from a facility could be attributed to the startup periods.     

Environmental impact assessment on production and material supply stages of lithium-ion batteries with increasing demands for electric vehicles

Journal of Material Cycles and Waste Management - Battery electric vehicles (BEVs) and hybrid electric vehicles (HEVs) have been expected to reduce greenhouse gas (GHG) emissions and other...     

Coherent array of branched filamentary scales along the wing margin of a small moth

In butterflies and moths, the wing margins are fringed with specialized scales that are typically longer than common scales. In the hindwings of some small moths, the posterior margins are fringed with particularly long filamentary scales. Despite the small size of these moth wings, these scales are much longer than those of large moths and butterflies. In the current study, photography of the tethered flight of a small moth, Phthorimaea operculella, revealed a wide array composed of a large number of long filamentary scales. This array did not become disheveled in flight, maintaining a coherent sheet-like structure during wingbeat. Examination of the morphology of individual scales revealed that each filamentary scale consists of a proximal stalk and distal branches. Moreover, not only long scales but also shorter scales of various lengths were found to coexist in each small section of the wing margin. Scale branches were ubiquitously and densely distributed within the scale array to form a mesh-like architecture similar to a nonwoven fabric. We propose that possible mechanical interactions among branched filamentary scales, mediated by these branches, may contribute to maintaining a coherent sheet-like structure of the scale array during wingbeat.     

Assessment of biological effects and harm to Japanese medaka due to carbonized carbon fibers generated by a pyrolysis carbon fiber recycling process

Journal of Material Cycles and Waste Management - Carbon-fiber-reinforced plastics (CFRPs) are used as structural materials in the aircraft and automotive industries owing to their lightweight and...