Recovery tests of 25 volatile organic compounds (VOCs) spiked into drinking water were performed under various test conditions to evaluate the effects of cooling experimental apparatuses and solvents and diluting water samples during preparation of calibration standard solutions and water samples on analytical precision for testing the VOCs in drinking water using a purge and trap-gas chromatography/mass spectrometry (PT-GC/MS). As a result, compounds with small Henry's constants (i.e., compounds with high volatility) were more affected in trueness and repeatability when cooling was not applied during the test operations. In addition, when the water sample was diluted, the trueness and repeatability was decreased even if cooling was applied during the test operations. Therefore, it is important to conduct test operations with cooling experimental apparatuses and solvents, and without diluting the sample water to obtain better analytical accuracy in VOC analysis of drinking water samples using PT-GC/MS.

Silver-containing nanoparticles (Ag-NPs) are now used in a wide range of consumer products for their antibacterial properties. Human exposure to Ag-NPs can occur not only through contact with these products but also through foods that have become contaminated with Ag-NPs released from these products into the environment. However, the status of NPs in foods remains unknown due to the lack of an analytical method for the examination of NPs contained in solid samples such as foods. Recent evidence suggests that Ag-NPs released into the environment may accumulate in filter feeders such as oysters. Here, we developed a method for measuring the concentrations of Ag-NPs in oysters using single-particle inductively coupled mass spectrometry (spICP-MS). Ag-NPs were extracted from oysters using one of four extraction procedures (ultrasonic crushing, alkali-treated hydrolysis, solubilization with surfactant, or enzymatic digestion), and recoveries of spiked Ag-NP (diameter, 60 nm) in terms of particle size, particle number concentration, and particle mass concentration were evaluated. Among the four extraction procedures, enzymatic degradation afforded the highest recoveries for particle number concentration (85±13%) and particle mass concentration (93±14%) and had the smallest effect on particle size (110±3%). Using our developed spICP-MS approach with enzymatic degradation, we examined 24 samples of rock and Pacific oysters purchased on the Japanese market between 2019 and 2020 and found that they contained Ag-NPs at 6.3×10⁵ to 7.7×10⁸ particles/g. The particle mass concentrations ranged from 0.13 to 98 ng/g, and an average of 1.2% of the total Ag was present as nanoparticles. The present data also suggest a difference in the size of the Ag-NPs accumulated in rock oysters (28±2 nm) and Pacific oysters (25±4 nm); further studies are needed to examine this finding in more detail.

Dioxins (PCDDs, PCDFs and Co-PCBs) in ambient air are collected using a high-volume air sampler (HVAS) equipped with a quartz fiber filter (QFF) and two polyurethane foams (PUF). The air samples are usually collected at a rate of 100 L/min for 7 days in Japan. In recent years, the concentration of dioxins in the air has been decreasing, making it difficult to obtain accurate concentrations and congener compositions. It is assumed that extending the sampling period would result in more accurate measurements by lowering the lower limit of detection and provide more accurate annual average concentrations. Therefore, we investigated how long the sampling period could be extended without loss of atmospheric dioxins. As a result, it was found that dioxins could be collected without loss for one-month sampling. Even during the three-month sampling period, atmospheric dioxins were collected almost without loss—the recovery rate of some volatile sampling spike compounds decreased during the summer months. Except for the summer months when temperatures are high, atmospheric dioxins can be collected without loss, even if the collection is performed for a six-month period. Even in long-term sampling, the adequate collection of dioxins in the air can be evaluated with a good recovery of sampling spikes—preferably with the addition of TeCB-#79, which is more easily lost.

We investigated the concentrations of 17 pharmaceutical and personal care products (PPCPs) in Nara prefectural sewage treatment plants. Sewage samples were collected at sewage treatment plants in the same river basin on the same day as the river water survey date reported earlier. Results showed that, among the PPCPs investigated for this study, only trimethoprim, valsartan, and DEET had removal rates exceeding 50% in both winter and summer at sewage treatment plants, indicating that most other investigated PPCPs were discharged into the environment with little treatment. Large-scale sewage treatment plants in the same river basin had similar removal rates for PPCP that showed relatively high removal rates if their treatment systems were the same. Comparison of influents among seasons and among plants revealed seasonal differences in influent concentrations, even among cities in Japan. Local specificity was observed among plants within the same river basin and in the river water, suggesting the need to elucidate the actual state of PPCP influents in the respective regions. Furthermore, comparison of PPCP concentrations in effluent and river water showed that most substances were detected at higher concentrations in the effluent, but only valsartan and DEET were detected at higher concentrations in a specific river than in the effluent, so we revealed the presence of major sources of PPCP other than sewage treatment plants.

Sixteen major to trace elements (Na, Mg, P, K, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Cd, Pb) in the liver of largemouth bass (Micropterus salmoides) captured at three lakes were determined by ICP-MS and ICP-AES to evaluate largemouth bass as an environmental indicator of lakes and marshes. The concentrations of major to trace elements in largemouth bass liver ranged from 13,100 g g-1 for P to 0.13 g g-1 for Cd and Pb. The concentrations in the livers of largemouth bass samples at Lake Sagami and Lake Shinsei showed that ten elements (Mn, Fe, Cu, Zn, As, Se, Rb, Sr, Cd, and Pb) were different between the two lakes. In addition, six elements (Mn, Fe, Cu, As, Se, and Sr) showed similarities between the lake surface water and largemouth bass liver. A result of a principal-component analysis using the elemental concentrations of 16 major to trace elements in largemouth bass livers for 11 samples at Lake Sagami, for 6 samples at Lake Shinsei, and one sample at Benkeibori moat showed a different tendency. Furthermore, the results using four elements (Fe, As, Rb, and Sr) as indices showed that largemouth bass from each lake could be clearly classified into three groups by plotting in combination with these elements.

日本では2020年に公共用水域におけるPFOS及びPFOAの指針値が定められたが，近年では代替PFASの使用が増加し，その環境影響が懸念される。そこで本研究ではISO 21675に準拠し，水試料中30種PFASの一斉分析体制を構築した。河川水の分析時，一部PFASはサロゲート回収率の低下が見られ，LC-MS/MS分析時のイオンサプレッションが原因と考えられた。超純水及び河川水を用いた添加回収試験では，PFAS回収率は各88～122％及び66～141％であり，各30種及び25種が回収率70～125％の範囲内であることから，分析精度が確認された。大阪市内河川調査では調査した30種中20種PFASが検出され，ΣPFAS₃₀濃度は 24～11,000 ng L^-1 であった。最も高濃度を示した神崎川では，その98％はPFHxAであり，フッ素樹脂メーカー事業場の影響が考えられた。6:2 FTSAは下水処理場放流水の影響を受ける地点から検出され，HFPO-DAは全地点から検出された。調査地域における2007年調査とのPFOS及びPFOA濃度の比較では，平均値で各10分の1及び7分の1に減少していた。

大気中マイクロプラスチック（AMPs）の存在が近年明らかとなったが，現状では未解明の点が多く，調査手法の確立および実態解明が喫緊の課題である。本研究では，感度や空間分解能に優れる顕微ラマン分光法を使用したものとしては国内で初のAMPs調査として，4地点（新潟曽和および川崎（都市），笠堀ダム（田園），小笠原（遠隔））における存在状況の把握を試みた。その結果，精度管理下においてAMPsが検出された（n＝32）。AMPsの大気中個数濃度は 0.52±0.24 MPs m^－3，種類はポリエチレン（PE），プラスチック樹脂（RES），ポリアミド（PA）の順に多く，粒径（フェレ径）は 7.6±3.7 μm，形状はいずれも粒子または破片状であり，既往研究の報告と矛盾しなかった。2023/11/14～12/12にかけて実施した集中観測（新潟曽和，川崎，笠堀ダムの並行測定）の結果から，地点間の平均濃度水準は概ね同等だが，週別変動は都市と田園とで異なる推移を示した。気象場や捕集地点の立地状況，潜在的な発生源の違いが結果に与えた影響は不明確だが，清浄な大気環境下でもプラスチック汚染のおそれがあると考えられた。手法の精度のさらなる向上およびその確立，他の大気汚染物質を含め観測データの蓄積による検証が必要である。

Currently, ion exchange resins are widely used to remove nitrate ions from water, but they have problems such as high production cost and difficulty to reuse, so there is a demand for the development of alternative adsorbents. In this study, we attempted to introduce the quaternary nitrogen (N-Q) to the activated carbon using the biomass material to enhance the nitrate ion adsorption in aqueous solution. Then, the relationships between nitrate ion adsorption and equilibrium solution pH (pH_e), the elemental ratio, and the surface functional group contents of the sample were investigated to examine the amount of the N-Q and its effect on nitrate ion adsorption. As a result, the amount of N-Q in the sample increased with raising the ratio of urea to pinecone, and the optimal weight ratio that can introduce a large amount of N-Q into the sample and improve nitrate ion adsorption performance was Pc:Ur:Zn=1:1.5:0.5. The sample prepared with the optimum weight ratio showed high nitrate ion adsorption (0.5 mmol/g) as a carbon material and maintained the high adsorption performance in a wide pH range. These results indicated that the relatively easy preparation method in this experiment efficiently could introduce the N-Q into biomass AC, which promoted nitrate ion adsorption in aqueous solution. Also, it would imply that the influence of N-Q amount on nitrate ion adsorption performance was greater than the specific surface area, which is general indicator of activated carbon adsorption capacity.