Thermal cracking of oils from waste plastics

Thermal cracking of decomposed waste plastic oil produces a good yield of olefins. The solvent extraction of such waste plastic oil seems to be efficient for increasing gas yields and recycling monomers. To assess the potential of monomer recovery from municipal waste plastics, the oils were cracked using a laboratory-scale quartz-tube reactor. The waste plastic oils were provided by two commercial plants of the Sapporo Plastic Recycle Co. and the Dohoh Recycle Center Co. in Japan. A model waste plastic oil made in a laboratory was also examined. Yields of ethene, propene, and other products were measured at different temperatures. Two-step pyrolysis reduces coking compared with the direct thermal degradation of plastics. The raffinates from waste plastic oils extracted by sulfolane were also cracked. The primary products were almost the same as those from nontreated oils. The maximum total gas yield was 78wt%–85wt% at 750°C, an increase of about 20wt% compared with that of nonextracted oil. Solvent extraction removes stable aromatic hydrocarbons such as styrene, which is more coked than cracked.     

Radionuclide transfer to fruits: A critical review. Foreword

After completion of the (Validation of Environmental Model Predictions) (VAMP) and (BIOspheric Model Validation Study) (BIOMOVS II) Programmes, the Division of Radiation and Waste Safety of the IAEA decided to promote a new co-ordinated research programme to continue activities in the area of biosphere modelling. As a result, the BIOMASS Programme on BIOsphere Modelling and ASSessment was launched in Vienna in October 1996. The Programme is scheduled to finish in October 2000. The overall objective of BIOMASS is to provide an international focal point in the area of biosphere assessment modelling. There are 3 Themes and 11 working groups in BIOMASS. The objective of the Theme 3 Fruits Working Group is to improve understanding of the uptake and transfer of radionuclides from different sources to fruit. As part of the work programme, a review was undertaken of the experimental, field and modelling information on the transfer of radionuclides to fruit.     

Exploring decentralized forest management in Ethiopia using actor-power-accountability framework: case study in West Shoa zone

Decentralized forest management is a pivotal approach in Ethiopia for balancing biodiversity conservation with demand for economic development, and for improving forest-dependent local peoples’ livelihoods. With the aim of filling the literature gap on Ethiopia, this paper explores the dynamics of decentralization in the forestry sector using the actor-power-accountability framework. Generally, three forms of decentralization are practiced: deconcentration to government administrative branches, devolution of selected decision-making power to local people, and delegation to enterprises. Although transfer of meaningful discretionary power to local people or to downwardly accountable lower-tier governments is a precondition for achieving positive outcomes from decentralization, this prerequisite has been realized in none of the three forms decentralization. Overall, three important trends emerged from the latest decentralization reform, which was a switch from the conservation-oriented deconcentration form of decentralization to the income generation-oriented delegation form of decentralization. Those trends are as follows: monetary income generation for local people through enterprise, albeit with possible risk of being deprived of income and subsistence opportunities on which local people depend for their livelihoods; moving decision-making power away from the grassroots; and lack of incentive to manage natural forests, a major source of biodiversity.     

Effect of dietary protein on the distribution of cadmium,zinc and copper in rats following the oral administration of cadmium

Cadmium, 100 μg/rat/day, was administered orally 100 times (total amount of Cd administered, 10 mg), under conditions of low protein intake. The total amount of Cd in the liver and kidneys was as follows: females fed 20% protein diets > females fed 5% protein diets > males fed 20% protein diets ≒ males fed 5% protein diets. A decreased Zn concentration was found in the liver of males and the pancreas of males and females fed with the 5% protein diet. The Cu concentration in the kidneys was markedly influenced by low protein intake.     

Development of a three-year-old child FE model

OBJECTIVE: Child crash dummies are conventionally used for safety performance evaluations of the child restraint system (CRS) in vehicle crash tests. To investigate injuries to various body regions of a child in detail, mathematical models are useful, and provide information that cannot be analyzed by crash dummies. Therefore, in the present research, a finite element (FE) model of a 3-year-old child has been developed by model-based scaling from the AM50 human FE model, THUMS (Total HUman body for Safety). METHODS: The dimensions of each body region were based on the anthropometry data of United States children, and material properties of child bone were estimated from data reported in the literature. Neck flexion, thorax impact responses, and torso flexion were validated against the response corridor of the 3-year-old Hybrid III dummy in calibration tests. A test of lap belt loading to the abdomen was also conducted. FE models of two different types of CRS, a 5-point harness and a tray shield CRS, were also made, and ECE R44 sled impact test simulations were conducted using the child FE model. RESULTS: The characteristics of the child FE model proved to be close to the Hybrid III and child volunteer corridor. In the ECE R44 sled test simulations using the child FE model, the head movement down and head rotation were large in the 5-point harness CRS, and chest deflection was large in the tray shield CRS. In both CRS types, the whole spine flexed in the child FE model. This behavior is different from that of the Hybrid III, where the thorax spine is stiff and only the cervical spine and lumbar spine flex. CONCLUSIONS: Although this child FE model has several limitations in areas such as the anatomical shapes and material properties of a child, this model can be a useful tool to examine the behavior of a child in impacts, which may be difficult to predict by using the Hybrid III dummy with its stiff thorax spine box.     

Mutagenicity of anaerobic fenitrothion metabolites after aerobic biodegradation

Previous studies have revealed that the mutagenicity of fenitrothion increases during anaerobic biodegradation, suggesting that this insecticide's mutagenicity could effectively increase after it pollutes anaerobic environments such as lake sediments. To investigate possible changes to the mutagenicity of fenitrothion under aerobic conditions after it had already been increased by anaerobic biodegradation, batch incubation cultures were maintained under aerobic conditions. The mutagenicity, which had increased during anaerobic biodegradation, decreased under aerobic conditions with aerobic or facultative bacteria, but did not disappear completely in 22 days. In contrast, it did not change under aerobic conditions without bacteria or under continued anaerobic conditions. These observations suggest that the mutagenicity of anaerobically metabolized fenitrothion would not necessarily decrease after it arrives in an aerobic environment: this would depend on the presence of suitable bacteria. Therefore, fenitrothion-derived mutagenic compounds may pollute the water environment, including our drinking water sources, after accidental pollution of aerobic waters. Although amino-fenitrothion generated during anaerobic biodegradation of fenitrothion was the principal mutagen, non-trivial contributions of other, unidentified metabolites to the mutagenicity were also observed.     

Reproductive effects and bioconcentration of 4-nonylphenol in medaka fish (Oryzias latipes)

The objective of this study was to investigate the reproductive success (fertility and fecundity) of medaka (Oryzias latipes) exposed to 4-nonylphenol (4-NP) in water and the viability of their F(1) offspring. In addition, we measured the bioconcentration of 4-NP in eggs. After a 21-d exposure to 100microg/l 4-NP, medaka showed reduced egg production and fertility. Hepatic vitellogenin levels were increased significantly in males treated with 10, 50 and 100microg/l of 4-NP. In the F(1) generations, the hatchability and time to hatching of embryos in the 100microg/l treatment group were adversely affected, and 2-7microg 4-NP/g egg was found in spawned eggs (the bioconcentration factor: 30-100). These results indicate that (1) 4-NP adversely affected the reproduction (fecundity and fertility) of adult medaka, (2) 4-NP accumulated in eggs through maternal transfer and (3) these levels of 4-NP were associated with adverse effects in the F(1) offspring.     

Seasonal variations in 228Ra/226Ra ratio within coastal waters of the Sea of Japan: implications for water circulation patterns in coastal areas

In this study, low-background gamma-spectrometry was used to determine the (228)Ra/(226)Ra ratio of 131 coastal water samples from various environments around Honshu Island, Japan (mainly around Noto Peninsula) at 1-3 month intervals from April 2003 until September 2005. Spatial variation in (228)Ra/(226)Ra ratios was also assessed by analyzing 34 coastal water samples from five areas within the Sea of Japan during May and June 2004. The (228)Ra/(226)Ra ratio of coastal water from all sites around Noto Peninsula shows seasonal variation, with minimum values during summer ((228)Ra/(226)Ra=0.7) and maximum values during autumn-winter ((228)Ra/(226)Ra=1.7-2). This seasonal variation is similar to that recorded for coastal water between Tsushima Strait and Noto Peninsula. The measured lateral variation in (228)Ra/(226)Ra ratios within coastal water between Tsushima Strait and Noto Peninsula is only minor (0.5-0.7; May-June 2004). Coastal waters from two other sites (Pacific shore and Tsugaru Strait, north Honshu) show no clear seasonal variation in (228)Ra/(226)Ra ratio. These measured variations in (228)Ra/(226)Ra ratio, especially the temporal variations, have important implications for seasonal changes in patterns of coastal water circulation within the Sea of Japan.