Process analysis of ozone formation under different weather conditions over the Kanto region of Japan using the MM5/CMAQ modelling system

We have assessed the contributions of individual physical and chemical atmospheric processes on ozone formation under different weather conditions during a typical summer month (August 2005) using the MM5/CMAQ modelling system. We found that the ozone episodes in the Kanto region are dominated by three major patterns, of which Patterns I and II are regular summertime pressure patterns with a 26% and 16% frequency of occurrence, respectively. A process analysis at two typical sites in the Kanto region – one located in the central region of Tokyo and the other located in the rural areas of Kanto – indicates that ozone formation is mainly controlled by advection, vertical diffusion, dry deposition, and chemical processes. The ground-level ozone concentrations are enhanced mainly by the vertical mixing of ozone-rich air from aloft, whereas the dry deposition and chemical processes mainly deplete ozone. By investigating the effects of each process under different weather conditions, we found that the significant decrease in ozone removal due to the chemical and advection processes under conditions of high stagnation is the most important cause of the enhanced levels of ozone in the central region of Tokyo. The results of this study can contribute to a better understanding of ozone formation in the Kanto region, and they may be valuable for local policy makers for further development planning.     

The Fukushima Nuclear Power Plant accident and exposures in the environment

The Great East Japan Earthquake has occurred on March 11, 2011, in the Tohoku District of Japan. Due to the earthquake, big tsunamis were induced, and they rushed to the Fukushima Nuclear Power Stations, causing severe accidents. Radioactive materials including I-131, Cs-137 and so on were emitted from the plant to the environment. The Japanese government, Fukushima prefectural government and other local governments have struggled against the accidents. The restricted area and deliberate evacuation area are set by the government, and the residents are evacuated. The dose rates in and around Fukushima Prefecture have been monitored by the governments and other involved organizations. Fukushima government has started the health management survey for all residents in Fukushima Prefecture including the questions on their activities for the estimations of their external doses.     

Removal of Pb(II) from water using keratin colloidal solution obtained from wool

The aim of this study is to investigate the use of keratin colloidal solution, which was obtained from wool, for the removal of Pb(II) from water. The addition of keratin colloidal solution (15 g L^?1, 0.30 mL) to a Pb(II) solution (1.0 mM, 0.90 mL, pH 5.0) resulted in the formation and precipitation of a Pb–keratin aggregate. Measurement of the Pb(II) and protein concentrations in the supernatant solution revealed that 88 and 99 % of the Pb(II) and keratin protein were removed from the solution, respectively. The maximum Pb(II) uptake capacity of keratin in the colloidal solution was 43.3 mg g^?1. In addition, the Pb–keratin aggregate was easily decomposed via the addition of nitric acid, which enabled the recovery of Pb(II). However, aggregation did not occur in solutions with Pb(II) concentrations below 0.10 mM. Therefore, we used a keratin colloidal solution encapsulated in a dialysis cellulose tube to remove Pb(II) from 0.10 mM solutions, which enabled the removal of 95 % of the Pb(II). From these results, we conclude that keratin colloidal solution is useful for the treatment of water polluted with Pb(II).     

Arsenic accumulation in duckweed (Spirodela polyrhiza L.): a good option for phytoremediation

Some unavoidable drawbacks of traditional technologies have made phytoremediation a promising alternative for removal of arsenic from contaminated soil and water. In the present study, the potential of an aquatic macrophyte Spirodela polyrhiza L. for phytofiltration of arsenic, and the mechanism of the arsenic uptake were investigated. The S. polyrhiza L. were grown in three test concentrations of arsenate and dimethylarsinic acid (DMAA) (i.e. 1.0, 2.0 and 4.0microM) with 0 (control), 100 or 500microM of phosphate. One control treatment was also set for each test concentrations of arsenic. The PO(4)(3-) concentration in control treatment was 0.02microM. When S. polyrhiza L. was cultivated hydroponically for 6d in culture solution containing 0.02microM phosphate and 4.0microM arsenate or DMAA, the arsenic uptake was 0.353+/-0.003micromolg(-1) and 7.65+/-0.27nmolg(-1), respectively. Arsenic uptake into S. polyrhiza L. was negatively (p<0.05) correlated with phosphate uptake when arsenate was applied to the culture solutions owing to similar in the sorption mechanism between AsO(4)(3-) and PO(4)(3-), and positively (p<0.05) correlated with iron uptake due to adsorption of AsO(4)(3-) onto iron oxides. Thus, the S. polyrhiza L. accumulates arsenic by physico-chemical adsorption and via the phosphate uptake pathway when arsenate was added to the solutions. These results indicate that S. polyrhiza L. would be a good arsenic phytofiltrator. In contrast, DMAA accumulation into S. polyrhiza L. was neither affected by the phosphate concentration in the culture nor correlated (p>0.05) with iron accumulation in plant tissues, which indicates that S. polyrhiza L. uses different mechanisms for DMAA uptake.     

Effect of carbon tetrachloride on sonochemical decomposition of methyl orange in water

Two types of sonicators were used for the sonochemical decomposition of methyl orange (MO) in the presence and absence of carbon tetrachloride (CCl4): One is a 45kHz ultrasonic cleaning bath (a low intensity sonicator) and the other is a 200kHz ultrasonic reactor (a high intensity sonicator). It was clearly confirmed that the rates of the sonochemical decomposition of MO increased with increasing the concentration of CCl4 in both sonicators. The enhancement effect of CCl4 was much higher in the high intensity sonicator than in the low intensity one: by the addition of 100ppm of CCl4, the decomposition ratio of MO with the high intensity sonicator became 41 times larger, while that with the low intensity sonicator became 4.8 times larger. Based on the obtained results, it was suggested that the formed cavitation phenomenon was different between sonicators. It was also suggested that the sonochemical decomposition of MO in the presence of CCl4 would be useful to evaluate the sonochemical efficiency, because the rate of MO decomposition can be effectively enhanced by the sonolysis of CCl4.     

Simplified heating time calculation using the Schmidt graphical method for PCB-contaminated capacitors undergoing the vacuum thermal recycling process

We discuss the use of the Schmidt graphical method to calculate the time required to heat a polychlorinated biphenyl (PCB)-contaminated capacitor in the vacuum thermal recycling process to the processing temperature of 400°C, and we evaluate the results of the heating time calculation by comparing the calculated values with the corresponding experimental values. The thermal conductivity and specific heat of the insulating paper and the carbonized paper in the capacitor were unknown, so we determined their values from experimental data obtained during the vacuum thermal recycling process. The capacitor element is a multilamination of aluminum foil and insulating paper, so we used an equation for a multilayer plane wall to calculate the value of the thermal conductivity. For the thermal conductivity and specific heat of the insulating paper impregnated with PCBs, we used values calculated from the mass ratios and thermal conductivities and specific heats of the individual materials. In addition, the physical properties vary according to the treatment because of the evaporation of PCBs and the carbonization of the insulating paper, so we modified the values of the thermal conductivity, specific heat, and density at the boiling point of the PCB and the carbonization point of the insulating paper before performing the calculations. Our calculated heating times were almost the same as, or were above, the experimental values, so we concluded that our method can be used as a simple calculation of the heating time.     

The effects of pH on fluoxetine in Japanese medaka (Oryzias latipes): acute toxicity in fish larvae and bioaccumulation in juvenile fish

Recent detection of fluoxetine in the aquatic environment and fish suggests a possibly high accumulation of fluoxetine; however, no report is available on the bioaccumulation of fluoxetine in aquatic organisms. Since bioaccumulation of fluoxetine was probably dependent on pH near the pK(a) value of 10.1, experiments were conducted approximately at pH 7, 8, and 9. Distribution coefficients between 1-octanol and water (D(ow)), and those between synthetic membrane vesicles (liposomes) and water (D(lip-wat)) were determined at pH 7, 8, and 9. The D(ow) and D(lip-wat) values increased significantly with increasing pH. Acute toxicity tests were performed using Japanese medaka (Oryzias latipes) prior to the bioaccumulation test, and 96-h LC(50) values were 5.5, 1.3, and 0.20mgl(-1) at pH 7, 8, and 9, respectively. In the bioaccumulation test, concentrations of fluoxetine and its major metabolite, norfluoxetine, in the fish body and liver were measured. The bioconcentration factors (BCF) of fluoxetine for Japanese medaka were 8.8, 3.0x10, and 2.6x10(2) in the body and 3.3x10(2), 5.8x10(2), and 3.1x10(3) in the liver at pH 7, 8, and 9, respectively. The BCF values were lower at pH 7 and higher at pH 9 mainly because of the increase in nonionized species with significantly higher hydrophobicity than the ionized species at pH values closer to pK(a). A similar trend was obtained for the concentration of norfluoxetine in the fish but the pseudo-BCF values (the ratio of the norfluoxetine concentration in the fish and the fluoxetine concentration in test water) were higher than the BCF value of fluoxetine at all pH conditions.     

Behavior of endocrine-disrupting chemicals in leachate from MSW landfill sites in Japan

Endocrine-disrupting chemicals (EDCs) in landfill leachates and the effluent from leachate treatment facilities have been analyzed by many researchers. However, seasonal and yearly variations and the influence of landfill age are still not clear. In this study, leachate was sampled on four occasions each, at different seasons, from two MSW landfills which receive different waste material. Then, the quantities of alkylphenols (APs), bisphenol A (BPA), phthalic acid esters (PAEs) and organotin compounds (OTs) in leachate were determined. By sampling leachate from landfill cells of different age, the long-term behavior of EDCs was studied. Furthermore, leachate was also sampled at different points in the process of a leachate treatment system, and then the behavior of EDCs in the facility was studied. The concentrations of APs were as low as in surface waters, and OTs were not detected (detection limit was 0.01 microg/l), while BPA and DEHP, which were the most abundant of the four substances measured as PAEs, were found in all the leachates that were measured. Concentrations of BPA and DEHP were almost constant regardless of season, except for a couple of low concentrations observed for BPA. The varying composition of landfilled waste did not influence BPA and DEHP in leachate. Concentration of BPA in raw leachate tends to decrease as the years go by, but the concentration of DEHP was observed to remain at a constant level. BPA was considerably degraded by aeration for leachates from the two landfills, except when the leachate temperature was low. Aeration, coagulation/sedimentation, and biological treatment could not remove DEHP.     

Drivers and constraints of waste-to-energy incineration for sustainable municipal solid waste management in developing countries

Journal of Material Cycles and Waste Management - Implementation of waste-to-energy (WtE) incineration has recently surged in developing countries, but the drivers of this growth and the...     

Formaldehyde Exposure in a Gross Anatomy Laboratory. Personal Exposure Level Is Higher Than Indoor Concentration (5 pp)

Goal, Scope and Background Cadavers for gross anatomy laboratories are usually prepared by using embalming fluid which contains formaldehyde (FA) as a principal component. During the process of dissection, FA vapors are emitted from the cadavers, resulting in the exposure of medical students and their instructors to elevated levels of FA in the laboratory. The American Conference of Governmental Industrial Hygienists (ACGIH) has set a ceiling limit for FA at 0.3 ppm. In Japan, the Ministry of Health, Labour and Welfare has set an air quality guideline defining two limit values for environmental exposure to FA: 0.08 ppm as an average for general workplaces and 0.25 ppm for specific workplaces such as an FA factory. Although there are many reports on indoor FA concentrations in gross anatomy laboratories, only a few reports have described personal FA exposure levels. The purpose of the present study was to clarify personal exposure levels as well as indoor FA concentrations in our laboratory in order to investigate the relationship between them. Methods The gross anatomy laboratory was evaluated in the 4th, 10th and 18th sessions of 20 laboratory sessions in total over a period of 10 weeks. Air samples were collected using a diffusive sampling device for organic carbonyl compounds. Area samples were taken in the center and four corners of the laboratory during the entire time of each session (4-6 hours). Personal samples were collected from instructors and students using a sampling device pinned on each person's lapel, and they were 1.1 to 6 hours in duration. Analysis was carried out using high performance liquid chromatography. Results and Discussion Room averages of FA concentrations were 0.45, 0.38 and 0.68 ppm for the 4th, 10th and 18th sessions, respectively, ranging from 0.23 to 1.03 ppm. These levels were comparable to or relatively lower than the levels reported previously, but were still higher than the guideline limit for specific workplaces in Japan and the ACGIH ceiling limit. The indoor FA concentrations varied depending on the contents of laboratory sessions and seemed to increase when body cavity or deep structures were being dissected. In all sessions but the 4th, FA levels at the center of the room were higher than those in the corners. This might be related to the arrangement of air supply diffusers and return grills. However, it cannot be ruled out that FA levels in the corners were lowered by leakage of FA through the doors and windows. Average personal exposure levels were 0.80, 0.45 and 0.51 ppm for instructors and 1.02, 1.08 and 0.89 ppm for students for the 4th, 10th and 18th session, respectively. The exposure levels of students were significantly higher than the mean indoor FA concentrations in the 4th and 10th sessions, and the same tendency was also observed in the 18th session. The personal exposure level of instructors was also significantly higher than the indoor FA level in the 4th session, while they were almost the same in the 10th and 18th sessions. Differences in behavior during the sessions might reflect the differential personal exposure levels between students and instructors. Conclusion The present study revealed that, if a person is close to the cadavers during the gross anatomy laboratory, his/her personal exposure level is possibly 2 to 3-fold higher than the mean indoor FA concentration. This should be considered in the risk assessment of FA in gross anatomy laboratories. Recommendation and Outlook If the risk of FA in gross anatomy laboratories is assessed based on the indoor FA levels, the possibility that personal exposure levels are 2 to 3-fold higher than the mean indoor FA level should be taken into account. Otherwise, the risk should be assessed based on the personal exposure levels. However, it is hard to measure everyone's exposure level. Therefore, further studies are necessary to develop a method of personal exposure assessment from the indoor FA concentration.