Study on polychlorinated dibenzo‐p‐dioxins and dibenzofurans in rivers and estuaries in Osaka Bay in Japan

In order to search the source of polychlorinated dibenzo‐p‐dioxins (PCDDs) and dibenzofurans (PCDFs) in blue mussel in Osaka bay, sediments from Osaka bay and from rivers running near an urban municipal incinerator were analysed for PCDDs, PCDFs and PCBs. The river and estuary sediments were all found to be contaminated with PCDDs at average levels of 9.8 and 12ppb on the dry basis, PCDFs of 7.8 and 5.1 ppb, and PCBs of 1600 and 1300ppb, respectively. The two sediments contained similar profiles of specific isomers and congeners of PCDDs and PCDFs with each other. In addition, there was observed positive close correlations between PCDD and PCDF levels in the two specimens as well as fly ash from urban municipal incinerators. These allow the conclusion that the main source of the two chemicals in Osaka bay is fly ash from waste incineration.     

Effects of buoyancy, transparency and zooplankton feeding on surface maxima and deep maxima: Comprehensive mathematical model for vertical distribution in cyanobacterial biomass

Inhomogeneous vertical distributions of the cyanobacterial biomass are widely observed during the summer season in stratified lake ecosystems. Among these are surface maxima characterized by surface scum formation and deep or subsurface maxima also known as deep chlorophyll maxima (DCM). The former occurs at the epilimnion in eutrophic lakes, and are usually caused by colonial cyanobacteria such as Microcystis. On the other hand, the latter occurs at the metalimnion and the upper part of the hypolimnion near the thermocline in oligotrophic lakes, and are referred to filamentous cyanobacteria such as Oscillatoria. The aim of this paper is to present a simple mathematical model that can simultaneously describe these phenomena including the annual and diurnal variations, emphasizing the roles of buoyancy regulation, transparency of the lake and zooplankton feeding on cyanobacteria. According to our computer analyses, the increased buoyancy, the low clarity of the lake and the low rate of zooplankton feeding take significant roles in formation of surface maxima, while the reversal of these factors makes deep maxima predominant. Our two-component model with nutrients and cyanobacteria can distinguish between two phenomena by changing the parameters for these factors, without altering the model itself.     

Life cycle assessment of integrated recycling schemes for plastic containers and packaging with consideration of resin composition

Many life cycle assessment studies have evaluated and compared the environmental performance of various technologies for recycling plastic containers and packaging in Japan and other countries. However, no studies have evaluated the combination of recycling technologies in consideration of the resin composition in terms of the quantity of each recycled product so as to maximize their environmental potential. In this study, 27 scenarios of recycling schemes for household waste plastic containers and packaging are developed through integrating a conventional recycling scheme with additional recycling schemes. The conventional recycling scheme involves municipal curbside collection and either the material recycling or feedstock recycling of waste plastics. The additional recycling schemes are feedstock recycling in steel works of the residue from conventional material recycling processes, and corporate voluntary collection and independent material recycling of specific types of plastic trays. Life cycle assessment based on the modeling of recycling processes considering the resin composition in terms of the quantity of each recycled product is applied to evaluate and compare these scenarios from the viewpoints of fossil resource consumption and CO₂ emission. The results show that the environmental loads are reduced in all scenarios including the additional recycling schemes compared with the conventional recycling scheme. However, the independent plastic tray recycling scheme exhibits lower additional environmental savings when the residue recycling scheme is integrated with the conventional material recycling scheme. This is because both additional recycling schemes aim to utilize polystyrene and polyethylene terephthalate, which would otherwise be incinerated as residue from material recycling processes. The evaluation of the environmental loads of plastic recycling with consideration of the resin composition in terms of the quantity of each recycled product makes it possible to investigate recycling schemes that integrate different technologies to maximize their environmental potential.     

Development of waste gasification and gas reforming system for municipal solid waste (MSW)

To achieve both high-efficiency power generation and high detoxification performance, advanced-type waste power generation plants such as pyrolysis and gas reforming plants are suggested. Further surveys on actual operational data of these plants are required in terms of reliability of the system when it is introduced to waste disposal sites. To verify the technical effectiveness of advanced-type waste power generation using the pyrolysis and gas reforming method, we evaluated 10?tons/day of municipal solid wastes (MSW) treated in a demonstration plant. A demonstration test was conducted over 100?days including 35?consecutive days of operation treating MSWs. The test results show high recycling performance and harmless nature of the plant which proves it to be an excellent waste recycling system. Major test results are as follows: (1) stabilization of waste treatment is possible with the wastes of various qualities, (2) clean gas is produced from the waste whose energy recovery ratio is approximately 40?%. (3) 99.3?% weight % of dried waste are recovered as valuable materials such as clean gas, char and metal, (4) total amount of dioxin emission to the outside of the plant is very small, down to 0.0051–0.018?μg?TEQ per ton waste.     

Feeding and growth of juvenile stone flounder in estuaries: generality and the importance of sublethal tissue cropping of benthic invertebrates

We investigated the feeding habits and growth of juvenile stone flounder (Platichthys bicoloratus) in several estuarine nurseries in Sendai Bay, Japan. Prey abundance and composition and juvenile diet varied largely among sites. However, polychaete palps (mostly Pseudopolydora kempi) and bivalve siphons (mostly Nuttallia olivacea) were positively selected and frequently consumed by juveniles, indicating the generality of sublethal feeding of juvenile stone flounder in estuarine nurseries. Recent growth rates determined by otolith microstructure analyses were dependent on juvenile body size and water temperature, but independent of juvenile density and food abundance. Growth rates were nearly maximal from March to May, suggesting that food conditions are nearly optimal in these estuarine nurseries. Sublethal tissue cropping of benthic invertebrates is thought to contribute largely to these high growth rates.     

Addressing sustainability through waste management: a perspective from higher education institutions in Southeast Asia

Journal of Material Cycles and Waste Management - Waste management is vital for global sustainable development. Sustainable development goals of a country would not be achieved if the waste...     

Evaluation of pressurized liquid extraction for the analysis of four pesticides in unpolished rice

The aim of to evaluate efficiency of this study was extraction pressurized liquid extraction (PLE) for the analysis of four pesticides, fthalide, etofenprox, fenitrothion, and isoprothiolane, in unpolished rice by comparing with homogenization as a reference technique. The concentrations of four selected pesticides obtained by PLE with acetonitrile at 130°C for 10 min × 2 cycles were comparable to those by homogenization with water-soaking. The repeatability of the analysis, represented as relative standard deviations (RSDs), were 1.4–3.6% (n = 3) for PLE at 130°C and 1.2–3.8% (n = 3) for homogenization with water-soaking. Recovery yields of surrogates were 75–88% and 87–109% for PLE at 130°C and homogenization with water-soaking, respectively, and these were satisfactory according to the method of positive list. This study suggested that PLE can be applied for the analysis of selected four pesticides in unpolished rice as well as homogenization with water-soaking.     

Maternal exposure to high levels of dioxins in relation to birth weight in women affected by Yusho disease

Background

Studies on the association of maternal exposure to polychlorinated dibenzo-p-dioxin (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) with decreased birth weight in humans have produced conflicting results. In Japan in 1968, an accidental human exposure to rice oil contaminated with PCDDs, PCDFs, and PCBs, led to the development of Yusho disease.

Objective

The Yusho cohort was used to evaluate the effect of maternal exposure to PCDDs, PCDFs, and PCBs on birth weight.

Methods

Blood samples, obtained from 101 Yusho women (190 births) who gave birth after exposure, were analyzed for congeners of seven PCDDs, ten PCDFs, and four non-ortho PCBs.

Results

Total PCDD TEQ (adjusted beta = − 161.9 g; 95% CI, −265.3 to − 58.6), total PCDF TEQ (adjusted beta = − 105.9 g; 95% CI, −179.5 to − 32.2), and total non-ortho PCBs (adjusted beta = − 178.4 g; 95% CI, −318.3 to − 38.5) levels were inversely associated with birth weight. Significant inverse associations with birth weight were also found for total PCDD TEQ, total PCDF TEQ, and total non-ortho PCB TEQ levels among male, but not female, infants. Significant inverse associations with birth weight were also found for nine congeners among all infants; the adjusted beta coefficients were largest for 1,2,3,6,7,8-HxCDD and smallest for 2,3,4,7,8-PeCDF.

Conclusion

In the setting of exposure to high levels of dioxins, maternal blood levels of PCDDs, PCDFs and PCBs are associated with lower birth weight in Yusho patients. The association exhibited gender-specific differences, as male infants are more susceptible than females to growth restriction induced by in utero dioxin exposures.     

Fluorophotometric Determination of Trace Amounts of Atmospheric Ozone

This work was initiated in an effort to obtain a better method for the manual determination of trace amounts of atmospheric ozone. The method described depends upon the fact that ozone oxidizes nonfluorescent 9, 10-dihydroacridine to fluorescent acridine. When the ethyl alcohol solution of acridine is acidified by 6N acetic acid, the fluorescence maximum occurs approximately at 482 mμ and its intensity is sufficiently strong to be useful in this analysis. Linear relationships between acridine concentrations and fluorescence intensities were obtained from 0.1 to 3.5 μg per ml. by measurement with a commercial fluorophotometer. The results indicated that the low concentrations of experimentally prepared ozone measured by this method were in good agreement with those obtained by the phenolphthalin method. This method appeared to be about twice as sensitive as the phenolphthalin method, but it is subject to some interference from nitrogen dioxide.