A GIS-based evaluation of the effect of decontamination on effective doses due to long-term external exposures in Fukushima

Despite the enormous cost of radiation decontamination, there has been almost no quantitative discussion on how much it would reduce the long-term external radiation exposure in the Evacuation Zone and Planned Evacuation Zone (restricted zone) in Fukushima. The aim of this study is to assess the effectiveness of decontamination and return options and to identify important parameters for estimating the long-term cumulated effective dose (CED) during 15, 30 and 70 year period using data on land-use, population and decontamination in the restricted zone (about 1100 km²) in Fukushima.     

Concentrations of organic wood preservatives in wood chips produced from wood wastes

We investigated the concentrations of wood preservatives in the wood chips produced in wood-waste processing facilities in 1988, 1998–1999, and 2001–2002. Among the wood preservatives used in the past in Japan, halophenols, including PCP, chlordane, and chlorpyrifos, had comparatively high detection rates and high average concentrations in the wood chips produced in 2001–2002. Aldrin and endrin were rarely detected, and DDT was already in low concentrations in those wood chips. Although several types of wood preservative were contained in the wood chips, their concentration levels depended on the sources of the wood wastes. In chips produced from wooden pallets, wooden forms for concrete working, or wood discarded from nondemolition sources, no organochlorine wood preservatives were detected, and chlorpyrifos and chlorophenols were detected at one order of magnitude lower than the average concentrations in chips produced from wood wastes discarded in house demolitions.     

Genotoxicity of substances extracted from construction materials

Construction waste such as road pavement and concrete is estimated to constitute about 50% of the total industrial waste in Japan, and the recycling of such material has recently become a prominent topic among construction engineers. It has also been suggested that various types of industrial waste be utilized as components of construction materials. This paper investigates the environmental safety of certain materials in terms of the elutions and genotoxicities of these substances. The substances extracted from some materials, such as emulsifier, ash, and sediment, were found to have genotoxic characteristics. The dose-related responses of the various materials and their genotoxic strengths are shown. Received: June 16, 1998 / Accepted: September 7, 1999     

Sexual dimorphism in sea lion pups: differential maternal investment,or sex-specific differences in energy allocation?

Proximal mechanisms underlying a faster growth rate in male compared to female California sea lion pups were investigated. Males are significantly larger at birth than females. Specifically, we asked if differential maternal investment contributed to enhanced male growth via: (1) larger mothers having disproportionately more male pups, (2) more time and energy put into foraging by mothers of male pups, and (3) greater milk production in mothers of male pups. We also considered four aspects of differential energy utilization and acquisition by male and female pups: (1) male pups attempting to save energy for growth by changes in behavior, (2) longer suckling bouts with mother and more sneak suckling of non-filial females by male pups, (3) lower maintenance costs in males via a lowered resting metabolic rate, and (4) increased assimilation efficiency in males. Our study showed that there are no differences in the size of females or length of foraging trips for mothers of male and female pups. Male pups received more milk from their mothers, but the difference was no longer significant when the larger body size of males was considered. There were no differences in either the activity budgets or suckling behavior of male and female pups. Male pups, however, did have lower resting metabolic rates than females. We conclude that enhanced male perinatal growth is a consequence of a larger size at birth, proportionally more milk from mothers to support the greater demands of larger body size, and lower maintenance costs due to a lower resting metabolic rate. Received: 28 April 1995/Accepted after revision: 25 July 1995     

Toxicity Testing of Leachate from Waste Landfills Using Medaka (Oryzias Latipes) for Monitoring Environmental Safety

To investigate the environmental safety of waste disposal landfill sites and of land reclaimed from such sites, we evaluated the toxicity of leachate from these sites by a combination of bioassays in the Japanese killifish medaka Oryzias latipes. We tested for lethal toxicity in adult and larval medaka and for hatching inhibition of embryos from eggs. As biochemical evidence of the effects of leachate exposure, CYP1A (EROD activity) and vitellogenin (Vtg) were induced. We also bioassayed water-treated leachate and downstream river water. Leachate solution was lethal to larval and adult medaka. Embryo hatchability was inhibited, and abnormal hatching, spinal deformity and anisophthalmia occurred in embryos exposed to leachate solution. CYP1A was induced by exposure to leachate solution diluted to 1.0%, and EROD activity was significantly higher than in control. Vtg and unknown proteins were induced in the sera of male medaka exposed to the diluted leachate solution. Conventional water treatments worked effectively to remove toxic compounds but did not work well to remove element ions, including heavy metals. Treated leachate produced neither lethal toxicity nor hatching abnormalities during the exposure period. Fish toxicity tests for leachate would be useful for monitoring the environmental safety of landfill sites.     

Investigation of perfluoroalkyl carboxylic and sulfonic acids in leachates from industrial and municipal solid waste landfills,and their treated waters and effluents from their closest leachate treatment plants

Journal of Material Cycles and Waste Management - Per- and polyfluoroalkyl substances (PFASs) are used in products, such as aqueous film-forming foam and fluorochemical surfactants, because of...     

Evaluation of waste pyrolysis characteristics in a pressurized fluidized bed reactor

To obtain the distribution of fuel components to gas, tar and char in a pressurized fluidized bed waste pyrolyzer, experiments were conducted with a laboratory scale fluidized bed reactor. Waste samples were fed batchwise from the top of the reactor into the fluidized bed of silica sand and pyrolyzed by nitrogen/nitrogen-O2 gas and the effects of pressure, particle size, heating rate and oxygen addition were investigated. In the case of rubber, the char yield tended to increase a little and the tar yield decrease over the pressure of 304-709 kPa. In comparison with the thermogravimetry data it was clearly demonstrated that the char yield from fluidized bed pyrolysis is much lower. A small amount of oxygen addition decreased both tar and char yields but its further increase did not affect them very much.     

Bioaccessibility of Cd and Pb in tailings from a zinc smelting in Brazil: implications for human health

Soils and wastes enriched with heavy metals may present ecological and human health risks. A considerable number of mining areas exist in Brazil, where high levels of metals have been found. However, studies of bioaccessibility of metals in soils/tailings from these areas are scarce, despite their potential informational contribution concerning exposure risks of residents near these areas. This study evaluated tailings collected from four sites of a zinc smelting area located in Brazil with aims to: (1) evaluate the presence of metals of potential concern; (2) investigate Cd and Pb bioaccessibility; and (3) determine the desorption kinetics of Cd and Pb. High concentrations of total Cd and Pb (up to 1743 mg Cd kg^?1 and 8675 mg Pb kg^–1) and great variability were found in the tailings, indicating the importance of adequate planning for their final disposal, in order to avoid contamination in the surrounding environment. Cadmium and Pb bioaccessibility percentages in the intestinal phase were less than 47 and 4 %, respectively, which represents significant fractions not available for absorption in the intestinal tract. However, this material has to be monitored since its bioaccessibility may increase with eventual physicochemical changes, releasing Cd and Pb. Desorption kinetics experiments revealed that Pb in the samples remained in less labile fractions, whereas Cd was found in more labile fractions, which is in accordance with the bioaccessibility results.     

Hyperaccumulator Thlaspi caerulescens (Ganges ecotype) response to increasing levels of dissolved cadmium and zinc

Hyperaccumulation of metals by plants involves at least three processes: efficient absorption by roots, efficient root-to-shoot translocation and hypertolerance through internal detoxification. In this study, Thlaspi caerulescens was separately exposed to Cd and Zn at 0, 50, 100 and 200 μ M for 7 d to monitor plant responses in hydroponics. Significant dose-dependent accumulation was observed for both metals, mainly in roots (up to 3.2 and 9.2 mg g ^?1 for Cd and Zn, respectively). However, Cd was more phytotoxic in terms of plant growth and photosynthesis. This higher toxicity was also evidenced by MetPLATE bioassay. Root exudation was significantly correlated to Cd and Zn translocation (r>0.85) proving its involvement in facilitating metal uptake. As for antioxidative responses, plants reacted to Cd and Zn by broadly exhibiting an elevation of glutathione reductase activity before declining at 200 μ M due to higher phytotoxicity. By contrast, superoxide dismutase activity was unlikely to be affected by both metals. Root-to-shoot apoplastic flow was traced using a fluorescent dye (trisodium-8-hydroxy-1,3,6-pyrenetrisulfonic acid; PTS), whose concentration in leaves increased to a certain extent with Cd and Zn accumulation, indicating that heavy metals have a comparable effect to drought or salinity in promoting the passive diffusion of water and solutes. Nevertheless, Cd at 200 μ M hindered the diffusion of PTS and consequently affected the apoplastic transport in plants.