Formation pathways of polychlorinated dibenzofurans (PCDFs) in sediments contaminated with PCBs during the thermal desorption process

Thermal desorption has attracted considerable interest as a remediation technology for the removal of dioxins and polychlorinated biphenyls (PCBs) from contaminated soils and sediments. Although several research groups have confirmed that polychlorinated dibenzofurans (PCDFs) are formed from PCBs during the thermal desorption of sediments contaminated with PCB, the formation pathways remain poorly understood. Herein, thermal desorption has been used to develop a greater understanding of the formation pathways of PCDFs from sediments contaminated with PCBs. PCB decomposition experiments of sediments contaminated with PCBs were performed over 5 min at 450 °C with a gas composition of 10% O(2)/90% N(2), either in the absence (Run 1) or presence (Run 2-4) of one of three different (13)C(12)-labeled PCB individual standards. The results of Run 1 showed that 99.96% of PCBs and 98.40% of polychlorinated dibenzo-p-dioxins (PCDDs) in the treated sediments had decomposed, whereas the concentration levels of PCDFs had increased by a factor of 31. The addition of different (13)C(12)-labeled PCBs to the sediment sample yielded different (13)C(12)-PCDFs isomer patterns, with formation pathways including loss of ortho-Cl(2), loss of HCl involving a 2,3-chlorine shift, loss of ortho-H(2) and dechlorination.     

Paternal expenditure is related to brood sex ratio in polygynous great reed warblers

In many polygynous animals, parents invest more heavily in individual sons than in daughters. However, it is unclear if these differences in investment are a consequence of sex differences in the demand of offspring related to sexual size dimorphism or a consequence of parental manipulation. Here, we report on parental food delivery frequency in relation to brood size and brood sex ratio in a wild population of polygynous great reed warblers Acrocephalus arundinaceus. We used the polymorphic microsatellite loci on the Z chromosome to sex chicks. We found that paternal feeding frequency (times/h per nest) increased not with brood size, but with the proportion of males in the brood, although the demand per nest was more closely related to brood size than to brood sex ratio. Additionally, the increase in rate of paternal feeding frequency in relation to the brood sex ratio was much higher than the increase in rate of nestling food demands. Maternal feeding frequency was independent of both brood size and brood sex ratio. These results strongly suggest that fathers preferentially invest in their sons. We propose that parents can afford sex-biased parental care in animals in which food provisioning is enough for all offspring to survive. Received: 22 January 1996/Accepted after revision: 30 June 1996     

Neighborhood influences on the diffusion of residential photovoltaic systems in Kyoto City,Japan

Environmental Economics and Policy Studies - This study investigates the factors influencing the diffusion of residential photovoltaic systems. Factors examined are related to social attributes,...     

The effect of the increase in urban temperature on the concentration of photochemical oxidants

An atmospheric dispersion model, where the inputs of meteorological field were calculated using a meteorological model, was used to reproduce the observed air pollution conditions for the typical fine day in summer period, especially the concentration of the photochemical oxidants. As well, the effects of an increase in the urban temperature and VOC emissions on the concentration of photochemical oxidants were also considered. The following conclusions were drawn.The observed air pollution levels were well modeled by the atmospheric dispersion model using in this study, although modeled NO levels were slightly lower than the observed levels. An analysis of the temperature data showed that a 1 °C increase in temperature leads to a maximal photochemical oxidant concentration of 5.3 ppb, which is an increase of 11%. Additionally, the effect on the photochemical oxidant concentration due to an increase in the vegetation-derived VOCs was more than double the effect due to an increase in the photochemical reactions. It was found that the temperature and photochemical oxidant concentration were linearly related up to a temperature increase of 3 °C. When the temperature increases up to 3 °C, the concentration of photochemical oxidants increases by 19 ppb. An analysis of the effect of vegetation-derived VOCs on photochemical oxidant concentrations showed that, the concentration of photochemical oxidants was 30 ppb higher in the afternoon by the effect of vegetation-derived VOCs, so even in metropolitan areas with relatively little vegetation, vegetation-derived VOCs have a strong impact on photochemical oxidant concentrations.     

H2O2/VisUV photo-oxidation process for treatment of waterborne hazardous substances—Reaction mechanism, rate model, and data for tubular flow and flow stirred tank reactors

This paper presents the chemical reaction engineering development of the H₂O₂/VisUV photo-oxidation process for treatment of hazardous waterborne substances, that occur in groundwater, leachates, and industrial wastewater. Reaction results, on benzene (BNZ), dichlorobenzene (DCB), trichloroethene (TCE), trichloroethane (TCA), and carbon tetrachloride (CTC), have been obtained, providing engineering data and models that can be used to size full-scale equipment. A photochemical flow stirred tank reactor (pcfSTR) and a photo-chemical tubular flow reactor (pcTFR) were used in the experimental work. Two experimental discoveries were made in the course of the work: (1) conventional thermal kinetics do not apply, the rate controlling variable is the photon flux, and (2) for the photo-chemical reactors used, the pcfSTR was more effective than the pcTFR. The following sub-topics are discussed: reaction mechanism, reactor hydrodynamics, photon flux effects, typical reaction data (on benzene and trichloroethane), and rate constants.     

Farmers’ attitude toward treated sludge use in the villages of West Bank,Palestine

An application of treated sewage sludge on agricultural land has been widely accepted, as this method is simple and economical for disposal of wastewater residues. When applied properly on an agricultural land, sludge can replenish organic matter and nutrients in soil. Although sewage sludge has been used in agriculture in many parts of the world, its acceptability varies with different cultures and beliefs among farmers. Farmers’ concerns on sludge use are primarily due to its anthropogenic origin, pollutants that it carries, a general perception of sewage being dirty, and its offensive odor. This paper aims to investigate farmers’ perceptions on land application of treated sewage sludge on their farm. This study targeted two farming communities, namely, Anza and Beit Dajan villages, located in Jenin and Nablus districts in the West Bank, Palestine. In this study, a sample of 106 farmers were randomly selected and surveyed through a mixture of structured and open-ended questions. Results indicated that, overall, farmers have positive perceptions on land application of sludge. A majority of the farmers are in favor of the concept of sludge use when a planned wastewater treatment plant is constructed and it becomes operational. Results also indicate that a majority of the farmers are in favor of using sludge for fertilizing fruit trees, rather than growing vegetables and other plants in a greenhouse, and that many of them have knowledge of sludge properties and advantages and disadvantages of sludge use in agriculture. Despite the positive perceptions by the majority of farmers, a small fraction of the farmers are in disfavor of the use of sludge for the following reasons: psychological and social concerns, potential health risks, and their religious beliefs. Results further suggest that the land application of treated sewage sludge can be accepted by more farmers if the consumers are willing to buy agricultural products fertilized by sludge, sludge meets the public health requirements, and sludge is available at low costs. To improve farmers’ perceptions on the land application of sludge, several measures are recommended.     

Solid health care waste management status at health care centers in the West Bank – Palestinian Territory

Health care waste is considered a major public health hazard. The objective of this study was to assess health care waste management (HCWM) practices currently employed at health care centers (HCCs) in the West Bank – Palestinian Territory. Survey data on solid health care waste (SHCW) were analyzed for generated quantities, collection, separation, treatment, transportation, and final disposal. Estimated 4720.7 m³ (288.1 tons) of SHCW are generated monthly by the HCCs in the West Bank. This study concluded that: (i) current HCWM practices do not meet HCWM standards recommended by the World Health Organization (WHO) or adapted by developed countries, and (ii) immediate attention should be directed towards improvement of HCWM facilities and development of effective legislation. To improve the HCWM in the West Bank, a national policy should be implemented, comprising a comprehensive plan of action and providing environmentally sound and reliable technological measures.     

Educational initiative of Osaka University in sustainability science: mobilizing science and technology towards sustainability

One of the most important and yet difficult challenges that modern societies face is how to mobilize science and technology (S&T) to minimize the impact of human activities on the Earth’s life support systems. As the establishment of inter-disciplinary education programs is necessary to design a unified vision towards understanding the complexity of human nature, the Research Institute for Sustainability Science (RISS) launched a new program on sustainability science in April 2008. The program expects to address the issue of how to use knowledge more effectively to understand the dynamic interactions between nature and human society. This paper first offers an overview of international and Japanese initiatives on sustainability education in which we highlight the uniqueness of the attempt by the Integrated Research System for Sustainability Science (IR3S). The paper then introduces the RISS program for sustainability science, addressing the principles and curriculum design of the program. The paper discusses the main problems and constraints faced when developing the program, such as institutional barriers in building a curriculum and obtaining cooperation from faculty. To challenge these barriers and limitations, the RISS uses the program as a platform to disseminate the idea of sustainability science across the university. This attempt helps us to obtain the continuing cooperation necessary to improve and maintain the program.