By the 1970s, Cr(VI) sludge was illegally dumped around Komatsu-gawa, Edogawa-Ku, Tokyo, in the metropolitan area of Japan. Even now, high level of Cr(VI) pollution is observed in water in street inlet. Although Cr(VI) is easily reduced to Cr(III) under reducing conditions, the concentration is very high (>150 mg/L) under the high pH (>11) and low Eh (<0 mV) condition in the inlet. In order to explain why such high concentration of Cr(VI) has been detected under the reductive condition, influence of pH, Eh on redox reaction of Cr(VI) was investigated by batch experiment using Cr(VI) solution prepared from chemicals and the contaminated water sample collected from the polluted inlet. Iron sulfate (II) was used as reductant. When the Cr(VI) chemical was used, Cr(VI) was reduced less with higher pH condition. When contaminated water sample was used, the redox reaction was also suppressed in the higher pH condition (pH>9). The results of batch experiment also showed that, with the lower Eh condition, the more Cr(VI) was reduced when sample water collected form the polluted inlet was used. And it is also showed that pH is a stronger factor which influence on concentration of Cr(VI) than Eh. The reason why high concentration of Cr(VI) was detected under low Eh condition at Komatsu-gawa seemed to be the suppression of reducing reaction by the high pH.

A simultaneous analysis method for poly(oxyethylene)alkyl ethers (AEs) in environmental water was developed using solid phase extraction-liquid chromatography-tandem mass spectrometry (LC/MS/MS). The target substances were those with an alkyl group that had 9–15 carbon atoms and an ethylene oxide molar addition of 1–15 (C9-15EO1-15). The electrospray ionization technique was used in the LC/MS/MS measurement. The method detection limit (MDL) of C12EOns, which is the main component of the AEs, ranged from 0.00043 μg/L for C12EO8 to 0.0052 μg/L for C12EO1, with the total MDL being 0.020 μg/L. The method quantification limit (MQL) ranged from 0.0011 μg/L for C12EO8 to 0.013 μg/L for C12EO1, with the total MQL being 0.052 μg/L. The total MDL and MQL of C9-15EO1-15 were 0.14 μg/L and 0.36 μg/L respectively. Tokoro River water samples were analyzed using this method. In 15 surveys, the concentration of AEs ranged from 0.0080 μg/L to 1.2 μg/L, and C12EOns were the main substances in all samples. The distribution of the number of EO additional moles of C12EOns differed depending on the sample. This is thought to be because of the different uses of the discharged AE products.

This study aimed to investigate the effect of coordination structure of Werner-type metal complexes on the bioluminescence intensity of marine luminescent bacterium Vibrio fischeri. Octahedral complexes of Co²⁺, Zn²⁺ and Cu²⁺ were prepared by mixing with varied concentrations of aqueous ethylenediamine or glycine as a ligand and the bioluminescence intensity of Vibrio fischeri was measured using ROTAS^TM-leachable kit. Toxicity of metal ion was apparently decreased by formation of complexes with ethylenediamine and the effect depended on the kind of metal ion and coordination structure. Meanwhile, although the toxicity was also reduced by the formation of glycine complexes, no clear dependency was found on the coordination structure, probably because of bioavailability of glycine for Vibrio fischeri via Na⁺-symport system in cell membrane.

The concentrations of benzotriazole UV stabilizers (BUVSs) in water bodies and the atmosphere were analyzed in Hyogo, Japan. Only UV-326 was detected in the water at four sites in the Hokkesantanigawa-River system, with a maximum concentration of 2,800 ng/L. BUVSs were detected in most of the analyzed sediment samples, with UV-326 as the dominant compound, followed by UV-327, UV-328, and UV-320. Based on these observations, BUVSs appear to accumulate more readily in sediments than in water because of their strong hydrophobicity. BUVSs were detected in all the analyzed atmospheric samples, and similar to the water and sediment samples, UV-326 was the dominant compound. These results suggest that the production and usage of UV-326 in Hyogo Prefecture are greater than those of other BUVSs. To the best of our knowledge, this is the first study that reports the presence of four BUVS substances (UV-320, UV-326, UV-327, and UV-328) in the atmosphere.

From April 2018 to March 2020 at the Niigata-Maki national acid deposition monitoring station, passive samplers for monitoring ozone were put with different types of rain shelters (with/without windbreak board at the bottom), and ozone concentrations by passive samplers were compared with those by the air pollutant monitor and also between each shelter. As a result, ozone concentrations were significantly different both between passive samplers in each shelter, and between passive samplers and the air pollutant monitor, and the difference of the latter showed correlation to wind speed. A new formula was devised for ozone concentration calculation that included wind speed as a parameter, and with this formula, the difference of ozone concentrations mentioned above became smaller. Through wind-tunnel simulation experiments, it was shown that the vertical component of wind strongly affected air movement in shelters, which suggested it might also affect monitoring by passive samplers.

An analytical method for polycarbamate in sediment by liquid chromatography tandem-mass spectrometry (LC-MS/MS) was developed. In this method, polycarbamate in sediment is methylated to ethylenebis dithiocarbamate dimethyl (EBDC-2Me) and dimethyldithiocarbamate methyl (DMDC-Me). Concentrations of polycarbamate are calculated from that of EBDC-2Me. The method detection limit (MDL) and method quantification limit (MQL) were 0.94 ng/g-dry and 2.57 ng/g-dry, respectively. The average recovery rate from sediment were 77.8% with a relative standard deviation (RSD) of 2.1%. Recovery rate was improved by the addition of methanol as solvent extraction in the case of organic-rich sediments. Polycarbamate added to sediment was completely lost for a day of preservation. In contrast, polycarbamate added to the crude extract was almost stable for three days of preservation, while it was completely lost for seven days of preservation. The concentrations of polycarbamate in the river and sea sediments sampled at Nagoya city were below the MDL.

Mercury concentrations in the atmospheric deposits were measured from April 2017 to April 2020 in Niigata City. As a result, total mercury concentration in the weighted average precipitation was 5.7±3.6 ng/L for total mercury, 2.8±3.0 ng/L for dissolved, and 2.9±2.0 ng/L for particulate. A high concentration of dissolved mercury was observed in June 2017, suggesting an increase in the concentration of gaseous oxidized mercury in the atmosphere. In addition, Asian dust was observed when the concentration of particulate mercury and the concentration of particulate matter increased, which may have affected the concentration of mercury. The amount of atmospheric deposition increased in winter when there was much rainfall and snow, and the concentration of dissolved mercury tended to increase.

In this study, we analyzed the estimation accuracy of the annual average value of 16 volatile organic compounds (VOCs) in the atmosphere according to the measurement frequency. As the analysis data, VOCs continuous monitoring data that has been observed hourly for 3 years at 6 points in Tokyo was used. In the case of 24-hours sampling, the coefficient of variation (CV) of the annual average value in the 30-days cycle to accurate annual average was 0.25 on average 16 substances. On the other hand, when the measuring day of the week is fixed, as in the case of the 7-days cycle, there were substances that had a significantly higher CV. Especially for trichloroethylene and dichloromethane, it was higher than that in the 30-days cycle. It was considered that this is influenced by the concentration fluctuation due to industrial and/or traffic activities, and it was speculated that if the measuring day of the week was fixed even once a month, the accuracy of the annual average value would decrease. In the monthly monitoring, the CV of the annual average value for one-week sampling was smaller than for the 24-hours sampling. It was estimated that the monitoring 4 times per year with one-week sampling was the same level or less than the CV of the monitoring 12 times per year with the 24-hours sampling. The annual average value by 1-week sampling of 4 times per year was as accurate as the value obtained by 24-hours sampling of 12 times per year that was commonly performed in Japan.

This study compares and analyzes the long-term trends of the currently published emissions of chemical substances and environmental monitoring results, and evaluates the impact of changes in emissions on air concentrations using Tokyo as a case study. In this study, we first estimated the emissions to the atmosphere of estimated releases of outside notification, for which no data by emission media were available, and analyzed them in combination with reported emissions. As a result, it was found that the emission categories that contributed to the reduction of atmospheric concentrations differed depending on the substance, reflecting the results of various emission control measures that have been taken for each substance. The analysis using the data reported on the use of chemical substances in the metropolitan government's ordinances suggests that the reduction in emissions was not due to the promotion of exhaust gas treatment (introduction of treatment equipment, etc.), but rather to the reduction in the amount of chemical substances used. When the toxicity weighted emissions of the released chemical substances was calculated, it was also estimated that the risk of formaldehyde and acrolein was large, which was significantly different from the top-ranking substances in terms of emissions. These analyses using published data can be carried out by the administrative departments of each local government, and this study proposed a method for understanding the status of air quality improvement in the region that can be implemented by the government.

A simultaneous determination method for ammonia and humic acid in water based on the chemiluminescence method was developed. Ammonia was separated by a porous Teflon tube (in a double tube), and separated ammonia was reacted with hypobromite to produce chemiluminescence. By using the synergistic enhancement effect of humic acid for the chemiluminescence, a detection limit for ammonia of 0.41 μmol dm^-3 was obtained without any interference from other compounds. Humic acid in the remaining solution coming out from the double tube also reacts with hypobromite to produce chemiluminescence. Ammonia interfered with this chemiluminescence, but the effect was saturated at ammonia concentrations higher than 1 mmol dm^-3. The slope for the calibration graph of humic acid was not affected by ammonia concentration, but the value of the intercept for humic acid increased depending on ammonia concentration. Therefore, if the ammonia concentration is known, the humic acid concentration can be determined. The detection limit for humic acid was 1.1 ppb. The present method was applied to the measurement of natural water, and the results obtained by the present method were consistent with those obtained by ion chromatography for ammonia and another reported chemiluminescence method using N-bromosuccinimide for humic acid.

In preparation for the leakage of chemical substances from factories and business establishments caused by disasters and accidents, it is desirable for each local government to grasp the daily stock amount of chemical substances in advance. This time, the technique to estimate the stock amount of chemical substances in factories and business establishments from PRTR notification data was examined.

Using existing survey data by the Ministry of the Environment, the relationship between the annual handling amount of chemical substances in factories and business establishments and the stock amount on the first day of the fiscal year and the end of the fiscal year was analyzed, and it was found that the stock amount was about 3.9 to 5.4% of the handling amount (about 2 weeks to 20 days). We have developed a method to estimate the handling amount from the release and transfer amount of PRTR notification data, and it seems that the estimation of the stock amount becomes possible by combining with this technique.

In Lake Shinji, an increase in Zn concentration has been observed in the upper layer of sediment after about 1970. The clarifying of the pollution sources of Zn in the lake is important for assessing the impact of Zn transported from the China continent on the aquatic environment in Japan. In this study, to obtain knowledge on the pollution sources of Zn in Lake Shinji, we measured the δ⁶⁶Zn of a sediment core. Moreover, we measured the δ⁶⁶Zn of aerosols collected in Hirado City, Nagasaki Prefecture, which has been strongly affected by air pollutants from the China continent. It was difficult to explain the δ⁶⁶Zn values (+0.11±0.14 (2σ) ‰) of anthropogenic Zn, which were estimated from the Zn concentration and δ⁶⁶Zn in the sediment core, on the basis of the contribution of aerosols with negative δ⁶⁶Zn values (-0.08±0.20 (2σ) ‰). In contrast, the δ⁶⁶Zn values (+0.05–0.08‰; literature data) of treated water from sewage treatment plants and runoff on receiving water in urban areas were similar to those of anthropogenic Zn in the lake. These suggest that Zn pollution in Lake Shinji is primarily attributable to the discharge of effluent such as treated water from sewage treatment plants and runoff on receiving water in urban areas; thus, the contribution of Zn from the China continent is small. This may be attributable to the release of large amounts of Zn into the environment, because Zn is used in large quantities in various products.

A simple and rapid pretreatment method for the analysis of PCBs in sulfur-containing water samples was investigated. Silver-coated copper powder mixed silica gel was combined in two ways (Ag-Cu column method and Ag-Cu stirring method) with a non-heating clean-up method using a purification column packed with silica gel and sulfuric acid silica gel and a concentration column packed with alumina and silver-modified alumina. Silver-coated copper powder mixed silica gel had high sulfur removal performance and usability. The Ag-Cu column method, in which silver-coated copper powder mixed silica gel was stacked on the purification column, showed high recovery rate of PCBs. In addition, the Ag-Cu stirring method, stirring with silver-coated copper powder mixed silica gel followed by non-heating clean-up method, had over 80% recovery rate of 209 PCB congeners. The Ag-Cu stirring method was able to remove a larger amount of sulfur than the Ag-Cu column method. Hexane extracts from waste water containing sulfur was pretreated by the Ag-Cu column method or the official method including alkaline treatment and silica gel column chromatography. The Ag-Cu column method had the same high purification effect and PCB quantification as the official method. Furthermore, the reduced recovery of clean-up spikes of nonachlorobiphenyl and decachlorobiphenyl observed by the official method was improved by the Ag-Cu column method. The Ag-Cu column method took less than two hours, and the amount of solvent used was less than one-twentieth of the official method. These results indicate that the pretreatment method combining silver-coated copper powder mixed silica gel and non-heating clean-up method is a simple and rapid method with high purification effect for sulfur-containing samples and enables the recovery of all 209 PCB congeners.

In preparation for the leakage of chemical substances from factories and workplaces caused by disasters and accidents, it is desirable for each local government to grasp the daily stock amount of chemical substances in advance. In this study, we tried to estimate the daily stock amount of chemical substances in factories and workplaces below-threshold-condition of PRTR in municipalities nationwide.

Using the release amount data of factories and workplaces below-threshold- condition of PRTR published by the Ministry of Economy, Trade and Industry/the Ministry of the Environment and economic census data, the release amount was prorated for each municipality in Japan, and each daily stock amount was estimated using the method of the previous research based on above release amount data. In some municipalities, there were cases where the daily stock amount in those factories and workplaces was more than that in PRTR notified ones, and it seems that daily attention to those factories and workplaces is also necessary as a preparation for disasters and accidents.