Transitions of usage and detection or concentration changes were summarized for the representative pesticides which had become research objects in water, fish and shellfish from Lake Biwa since 1960's. The concentrations of HCH and DDT in corbicula from Lake Biwa were surveyed for the first time in 1963, and similarly in 1966 ～1976 for those in Isaza from northern basin of Lake Biwa. Further, the concentrations of organochlorine pesticides such as HCH, DDT and chlordane in crucian carp and Japanese dace from Lake Biwa have been surveyed since 1975. It was clarified by the concentration survey of HCH isomers in water from Lake Biwa and Yodo River Basin in 1975 that the order of concentration ratios of HCH isomers (β＞α＞γ＞δ) in water from all areas of Lake Biwa was different from that (α＞β＞γ＞δ) in water from normal seas or rivers and the percentage of β-HCH in the water from Lake Biwa was high, 75 %. A large quantity of PCP was used as a paddy herbicide in Japan in 1960's and a great damage was caused to fish and shellfish in all littoral zone of Lake Biwa in 1962. CNP was registered as a herbicide in 1965 and had been used in Shiga Prefecture since 1966. The concentrations of CNP in Isaza from northern basin of Lake Biwa were surveyed in 1963 ～1987. Concentration survey data in water, fish and shellfish from Lake Biwa in 2000 ～2014 were summarized for insecticides (diazinon, fenitrothion and fenobucarb), fungicides (iprobenfos and isoprothiolane) and herbicides (molinate, bromobutide, simetryn and mefenacet) which were registered as pesticides in Japan from 1955 to 1986 and continuously used in the present.
Total Volatile Organic Compound (TVOC) measurement is one of the effective methods which evaluate indoor air pollution by volatile organic compounds (VOCs). In order to carry out this TVOC measurement by solvent extraction method instead of thermal desorption method, pore structures of the adsorbents were evaluated for their applicability in the analysis of TVOC and extraction conditions of solvent extraction were optimized. The results of adsorption and desorption test show the following three point: adsorbents with micro pore area higher than 1000 m2/g absorb strongly the VOCs with boiling points lower than 100 ℃, the adsorbents with pore diameter higher than 2 nm were able to desorb polar VOCs efficiently and the adsorbents with mesopore ratio more than 30 % had high desorption ratio of VOCs such as styrene and trimethylbenzene that are difficult to desorb. In the optimization of the extraction conditions, ultrasonic extraction temperature and extraction solvent were examined. As the result of optimization, the optimum condition was 20～30 ℃ of temperature and carbon disulfide containing 5 % acetone was used as extraction solvent. In this condition, high adsorption and desorption efficiency were obtained in the 38 kinds of compounds examined in this research.
Degradation of acetaldehyde using natural clay mineral, allophane was investigated in the dark and during UV irradiation in order to confirm its catalytic activity. A slight amount of acetaldehyde in gas phase was degraded and converted to acetic acid or carbon dioxide and water in the dark. The degradation was significantly promoted by the UV irradiation. Allophane should absorb UV light and convert its energy to heat energy because it is not a photocatalyst. The only surface of the allophane particle reached a high temperature. The acetaldehyde adsorbed on the allophane particle was degraded due to its catalytic activity.
High Cr(VI) contaminants have often been detected in groundwater and soils around chromium slag dumping site in Tokyo. The actual status of Cr(VI) seepage in Ojima-Komatsugawa Park was surveyed from January to December 2016, followed with examination of its causes. Firstly, quite heavily concentrated Cr(VI) was detected in seepage water from permeable pipe at the Wansaka Field in the Park. The 50 mm of total rainfall was found to be the trigger for Cr(VI) to leach and spread to the sidewalk. Secondly, Cr(VI) exceeding the standard value concentration flows out into the sewage at the catch basin in Komatsugawa area during rainfall. Leakage at the both points could not be directly related to groundwater level. Results indicated that rainfall causes seepage of Cr(VI), which results in the ongoing pollution in these areas. There had been some attempts to remediate the pollution by applying iron sulfate, however, the investigation revealed significance of further development for fundamental solution.
A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for simultaneously measuring bisphenol A (BPA), chlorinated BPAs (ClxBPAs), and brominated BPAs (BryBPAs) unintentionally generated in wastewater treatment plants (WWTPs). The main purpose of this study was to develop a non-derivatizing measurement method based on LC/MS/MS to analyze BPA, mono-, di-, tri-, and tetra-substituted BPAs by the chlorine or bromine groups in the aromatic rings (11 chemicals in total) via full separation and selective quantitation. In this method, the limit of detection for the chemicals was found to be within 0.01-0.16 µg/L, with recoveries of 50.6-77.9 % and relative standard deviation of 4.3-16 %. We also investigated halogenated BPAs generated by sterilizing the water treated by the WWTP with sodium hypochlorite. BPA and Br4-BPA, which are usually contained in industrial products, are the more abundant BPA congeners before the sterilization process. In one plant that receives a large amount of industrial wastewater, the concentrations of almost all halogenated BPAs decreased after the sterilization process. The concentration of Br4-BPA significantly decreased after the sterilization, while that of Cl4-BPA tended to increase. This suggested that Cl4-BPA was generated from BPA as well as halogenated BPAs (particularly Br4-BPA) during sterilization. Finally, non-targeted analysis using accurate mass measurement with LC/Q-ToFMS also discovered three other chemicals unintentionally generated in the effluents from the sterilization process, such as chlorophenol as a precursor of chlorinated dioxin, which is related to BPA congeners. Chemicals with the elemental compositions of pharmaceuticals were also found.
A new, comprehensive method for measuring selected aromatic VOCs in low concentrations in air was developed. The method is composed of selective sampling for benzene, toluene, xylene and ethyl benzene (Aromatic VOCs) by using a combination of two different adsorbent tubes, followed by thermal desorption and detection of whole components by a FID device. The adsorbents were selected by testing adsorption abilities for the target compounds, using an experiment system with model gases; the combination of Tenax TA and Carbotrap B adsorbents was found to be most suitable. The measurement method provided 0.1 μg/m3 of detection limit that corresponded to 0.19 ppbC and 0.3 μg/m3 of quantitation limit that corresponded to 0.58 ppbC as toluene equivalent concentration, which enabled the measurements in and around recycling plants of waste plastics. The maximum air sampling amount of 200 L was confirmed without breakthrough phenomena. In case of coexisting volatile aliphatic compounds such as acetone, which could be firstly removed by Carboxen 1000 adsorbent that has high adsorption ability for a wide range of compounds, and the target aromatic VOCs can be selectively determined.
In this study, we have developed the rapid and simple analytical method by FT-IR for dithiocarbamate pesticides: Mancozeb, Maneb, Ziram, Propineb and Thiuram. These pesticides are used in various crops as insecticides and fungicides. Spirodiclofen, Chlorfenapyr and Cyenopyrafen which were often used for citrus fruits were also examined. The developed analytical method consists of the following sequence of operation: wiping with water-soluble fiber, filtration concentration, and FT-IR analysis (transmission method). Linear calibration curves were obtained for all pesticides tested. In addition, the detection lower limit for each pesticide was low enough to comparison with the pesticide maximum residue level. Especially, the average recovery rate of dithiocarbamate pesticide in tomato was more than 70%. Kiyomi and green peppers also had average recovery rates of 60% or more. Conversely, the recovery rate of plums was low, and the average recovery rate was less than 50%. PLS quantitative model for calculating the total amount of dithiocarbamate pesticide (carbon disulfide conversion value) was also prepared. By using this PLS quantitative model, it was possible to measure the total amount of dithiocarbamate pesticides even if more than two dithiocarbamate pesticides are used. These results shows that this method is enable to do rapid screening of pesticides on site and it has great potential for application in food safety and security.
In this study, activated carbons were prepared from Moso bamboo by N2 carbonization under N2 gas atmosphere, using H3PO4 as activator and oxidized by (NH4)2S2O8 for the removal of Cd(II). The physicochemical properties of the prepared activated carbons (BAP) and commercially available bead-shaped activated carbon (BAC) were compared. The characterization results showed that BAP had higher surface area and mesopore volume compared with BAC, and the oxidized sample BAP1 had more surface functional groups. Adsorption equilibrium data were analyzed by the Langmuir and the Freundlich models. The adsorption equilibrium data were well described by the Langmuir model and the maximum adsorption capacity of BAP1-Na was found to be 0.721 mmol/g, which was greater than that of BAC1-Na. In the adsorption thermodynamics parameters study, the adsorption was spontaneous, favorable and exothermic. The experimental kinetic data were best fitted to pseudo-second-order model, and adsorption rate of BAP1-Na was faster than that of BAC1-Na. The prepared BAC1-Na showed better adsorption capacity for Cd(II) adsorption, and pH, oxidation time, adsorbent dosage and temperature also affected adsorption capacity of Cd(II).
Daily dietary exposure level of lead was estimated by market basket survey and low-contamination lead analysis. We collected 151 food samples of 17 food categories at supermarkets in Shizuoka city, Japan, and prepared 17 composites by mixing the food items in each of the categories after pretreatment and cooking. The composite was digested with ultrapure acid in a clean room and lead concentration was measured by ICP mass spectrometry. Lead was detected in all of the composites at the concentration of 0.21 to 124 ng/g fresh weight. Daily dietary exposure level of lead in Tokai district was calculated by multiplying lead concentration with daily intake of each of the 17 food composites, and by summing them all to find 4.69 μg/day. The obtained value is considered reliable because lead was detected in all of the composites: inclusion of "undetectable" composites generally results in uncertainty in daily exposure estimation based on market basket survey. "Algae" composite contributed most to the total daily exposure (28.8 %), which was followed by "Beverage" (13.8 %) and "Vegetable" (12.2 %) in this order. The present result will be valuable in the assessment and management of risk due to lead exposure in Japan.
Manganese concentrations and pH in a small, tea field river catchment were measured in 1998 and 2015. The pH levels dropped between May and June of 1998, but in 2015 there were few changes throughout the year. This difference is hypothesized to have been due to reduced fertilizer use between April and July and improved fertilization methods. While manganese concentrations were consistently lower in 2015, further investigations of manganese loading are required. Furthermore, a comparison of field soil and forest soil indicates that one factor leading to high manganese concentrations observed in a small river was a corresponding high concentration in tea field soils; additional factors include significant water-soluble components, exchangeable ions, and the exposure of carbonates, which are soluble in weak acids.
We studied variations in annual pesticide concentrations in two rivers in the Niigata Prefecture from April 2012 to March 2014 using GC/MS and LC/MS. Of the 83 pesticides targeted, 38 were detected in the Shin River and 25 in the Shinano River. Herbicides used mainly in paddy fields were detected more frequently, and at higher concentrations, than fungicides and insecticides. Although the pesticide concentrations in the Shin River were higher than those in the Shinano River, most pesticides were detected around the farming season for both the rivers. A small number of herbicides used only in paddy fields were detected in both rivers in winter. In this study, all pesticide concentrations were under their corresponding standard criteria.