A method to quantify regular graphite and turbo-stratified graphite (TS-graphite) forming the free carbon in ductile cast iron was developed using X-ray powder diffractometry. Iron in accurately sampled 2–4 g of the ductile cast iron powder was decomposed using hydrochloric acid without heating, and the residue was centrifugally separated. Graphite, TS-graphite, wustite (FeO), and amorphous silicate were identified in the residue. Calibration-standard mixtures were prepared by mixing corundum (α-Al2O3), griceite (LiF), and graphite powder which showed the most similar full-width at half-maximum value of (002) line to that of graphite in the ductile cast iron sample. The calibration curve of graphite showed good linearity, with a range of 0–200 mg corresponding to the 0–5.0 mass% of graphite in the 4.00 g of the cast iron sample. The quantitative value of total graphite in the ductile cast iron sample was 3.17 mass% with 8.0% of relative standard deviation for n = 5. The peak area ratio of graphite and TS-graphite was calculated using Rietveld refinement by assuming the same atomic scattering factor for each graphite measurement. The concentration ratio of graphite and TS-graphite were 67.8 and 32.2%, respectively. The analytical values of graphite were in good agreement with those of the NIST gray cast iron standard material, with concentration ratio of 53.7% and 46.3% for graphite and TS-graphite, respectively.

Behavior of radioactive caesium, derived from Fukushima Dai-ichi Nuclear Power Plant Accident, in river water and sediment investigated during 2012–2016. Concentrations of radioactive caesium in river water and sediment were decreased with time exponentially. The residence half-life of radioactive caesium in the river water and sediment were 0.788–1.50 year for 134Cs, 1.22–2.17 year for 137Cs. Any decrease in radioactive caesium concentration in the Tama river is because of weathering effect than radioactive decay. Concentrations of suspended radioactive caesium temporarily increased when sediments were resuspended due to rain. On the other hand, dissolved radioactive caesium is not easily impacted by this factor. Radioactive caesium concentration in sediments was considerably higher than that in river water. It indicated that much of the radioactive caesium in the Tama river existed in the sediments. Sequential extraction, elemental and crystal phase analysis were performed on the sediments and examined the chemical state of radioactive caesium as well as the adsorption mechanism. Radioactive caesium in sediment was present in a stable chemical form, and there is possibility that radioactive caesium was incorporated in biotite.

Suppression of heavy metal elution from municipal solid waste incineration (MSWI) fly ash by cement or geopolymer solidification was studied. When these approaches are implemented, however, the volume of the solidified body increases as a consequence of the solidifying agent addition. Considering that residual landfill disposal capacity is decreasing in the long term, a novel method to suppress the elution of heavy metals from MSWI fly ash without decreasing the disposal capacity is needed. We studied four different water repellents and the results indicated that heavy metal elution can easily be suppressed by impregnating the incineration fly ash with commercially available silane oligomers, alkyl alkoxysilane compounds, and water repellents like fatty acids.

Total reflection X-ray fluorescence spectrometry (TXRF) was applied to the analysis of Pb in an elution test (Japanese leaching test No. 13) of municipal solid waste incineration (MSWI) fly ash. A solid phase extraction method (SPE) with chelating resin was combined as a pretreatment for TXRF to remove the deposition of salts in spots of drying eluate on the specimen plate. After treatment by SPE, the accumulation of salt in drying spots on the silica glass plate was decreased significantly. In comparison with Ga internal standard of the TXRF spectra of the drying spots before SPE treatment, the X-ray intensities of matrix components such as K, Ca, Cl, Br and so on decreased to almost 1/100 after SPE treatment. The relative standard deviation ( n = 5) of the intensity ratio of Pb to Ga as an internal standard element was decreased from 20 . 7 % to 2 . 2 %. The detection limit was reduced from 0 . 07 mg L − 1 to 0 . 007 mg L − 1 , showing that the detection sensitivity was improved about 10 times. The combination of SPE and TXRF is a rapid, simple, and precise method for the determination of Pb in eluate from MSWI fly ash.

A rapid sample preparation method and a correction method achieving accurate quantification were developed for the on-site determination of heavy metals (Cr, As, Se, Cd, and Pb) in soil using a handheld X-ray fluorescence spectrometer. A soil sample was roughly crushed using a tablet crusher and a glass rod. The crushed sample was filled in a plastic container (28 mm of diameter and 10 mm of height), and a surface of the sample was covered with a polyester film. The sample was analyzed using a handheld X-ray fluorescence spectrometer after fixing the sample container to an acrylic jig. The moisture content in soil was measured by a refractive index-type mobile soil-moisture meter, and the concentrations of heavy metals obtained using the handheld X-ray fluorescence spectrometer were corrected to that in dried soil by a quantitative correction using the moisture content. The proposed method does not require a power supply in any analytical step, and is applicable to rapid and accurate determinations of heavy metals in soil.

A rapid, simple technique combining disk solid-phase extraction and handheld X-ray fluorescence (XRF) spectrometry was developed for the on-site determination of As, Se, and Cr(VI) in drinking water. For the preconcentration of As, Se, and Cr(VI), a 50-mL aqueous sample was adjusted to pH 4, followed by passage through a Ti-loaded anion-exchange disk (Ti-AED). Both sides of the Ti-AED were coated with an adhesive cellophane tape prior to drying using a cordless hair iron, followed by a handheld XRF measurement. The Ti-AED adsorbed As(III), As(V), Se(IV), Se(VI), and Cr(VI) in water without requiring oxidation and reduction. The detection limits of As, Se, and Cr(VI) were all 1.0 μg L^1־. Good recoveries were obtained by measuring certified reference materials, and spiking natural mineral water with As, Se, and Cr(VI). As the proposed method does not require a power supply or toxic reagents in any analytical step, it is suitable for the on-site determination of toxic elements in drinking water.

市販試薬中に存在する天然放射性核種を用いて，γ線スペクトロメトリー用のディスク型γ線源の作製を試みた。天然放射性核種である40Kと176Luを含む市販試薬をそれぞれ溶解後，ゼラチンと少量の食用着色料を添加し，液体をガラス繊維フィルターに滴下することで線源とした。滴下量から算出した放射能を用いて，γ線スペクトロメトリーにおけるディスク型γ線標準線源の検出効率曲線を作成した。検出効率曲線の妥当性は，ディスク型γ線標準線源と同型の認証標準試料の分析結果を認証値と比較することで評価した。認証標準試料中の放射性核種濃度の認証値と作成した検出効率曲線から得られた定量値はよく一致した。固相抽出とγ線測定を組み合わせて雨水中の放射性核種の定量分析に適用したところ，良好な定量値が得られた。ディスク型γ線標準線源は，市販の試薬から作製できるため，管理区域外でのγ線スペクトロメトリーに適用できる点が利点である。

A calibration method of gamma-ray spectrometry for radionuclides in environmental samples has been developed using three natural radionuclides included in commercially available chemical reagents. A detection efficiency curve was obtained by measurements of K-40, La-138 and Lu-176 identified in gamma-ray spectra of chemical reagents KCl, LaF3 and Lu2O3, respectively. The detection efficiencies were calculated for gamma rays in the energy range from 202 to 1461 keV using standard sources. Validations were carried out with determinations of the activity concentrations in geochemical reference rock samples and radioactive standard materials. The experimental results for standard materials were in good agreement with the certified value. Thus method enables one to easily prepare a detection efficiency curve, and to estimate the activities of several radionuclides in environmental samples outside of a radiation controlled area.

Fukushima-derived radiocesium (Cs-134 and Cs-137) was spread out all over the world after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. After, this accident, radiocesium was detected in soil at the Koshinetsu and Kanto regions. In this study, the activity concentration and the chemical forms of radiocesium in soil were analyzed for predicting any long-term effect of radiocesium in soil at low-dose areas. It is revealed that the distribution of radiocesium depends on the kind of clay minerals in soil. During passing years after the FDNPP accident, the activity concentrations of radiocesium in soil were nearly constant because of the insoluble chemical form. It is suggested that radiocesium would be fixed to minerals in soil for a long time.

福島県で採取された都市ごみ焼却飛灰で放射性セシウム分析用標準試料を調製した。元素組成，均一性，保存性を検討することで，都市ごみ焼却飛灰中放射性セシウム分析用の標準試料として利用可能であるかを評価した。元素分析の結果から調製した試料はカルシウムを主とした組成であり，自己吸収補正を施した値付けを最初に行うことで，以降の分析が容易になる。Cochran 検定および分散分析の結果から調製した標準試料は等分散であり，相対標準偏差 (n＝25) が 134Cs で 3.0 %，137Cs で 0.94 % と均一な試料であった。提案した標準試料は実試料をベースに各施設で調製可能であるため，放射性セシウム濃度の品質保証に活用できると考える。放射能測定用の焼却飛灰標準物質は現在のところ頒布されておらず，調製した標準試料は放射性セシウムを含む都市ごみ焼却飛灰研究に応用できると考えられる。

A rapid and simple method using handheld X-ray fluorescence analysis after disk solid-phase extraction was developed for the on-site determination of Mn, Fe, Cu, Zn, Cd, Hg and Pb in drinking water. A 50 mL aqueous sample was adjusted to pH 5 with acetate buffer, and then passed through an iminodiacetate chelating disk to preconcentrate heavy metals. The chelating disk was coated with adhesive cellophane tape, and then dried at 100 degrees C for 60 s. The disk was examined by handheld X-ray fluorescence spectrometer. The detection limits were 6.6 mu g L-1 for Mn, 9.4 mu g L-1 for Fe, 4.0 mu g L-1 for Cu, 3.6 mu g L-1 for Zn, 7.6 mu g L-1 for Cd, 4.4 mu g L-1 for Hg and 3.2 mu g L-1 for Pb. Spike tests comprised of 40 mu g L-1 and 100 mu g L-1 of heavy metals in natural mineral water and well water samples demonstrated that quantitative recoveries were achieved (89.0-110 %). Since the proposed method did not require an electronic power supply and toxic reagents in an analytical step, it is suitable for on-site determination of heavy metals in water.

Trace amounts of Cr, Zn, Cd, and Pb were determined by metal furnace atomic absorption spectrometry using absorption tubes. Various absorption tubes were designed as roof- and tube-types, and fixed above the metal furnace in order to extend the light path length. Aqueous standards and samples were injected in the metal furnace and atomized in a metal atomizer with an absorption tube (6 cm length, 15.5 mm diameter). The used of an absorption tube resulted in an enhancement of the atomic absorbance. The ratios of absorbance values with and without the roof- and tube-type absorption tubes were 1.33 and 1.11 for Cr; 1.42 and 1.99 for Zn; 1.66 and 1.98 for Cd; and 1.31 and 1.16 for Pb, respectively. The use of an absorption tube was effective for Zn and Cd analysis, as the absorbance values for these low boiling point metals doubled. The proposed method was successfully applied in the determination of Zn in tap water.

A preparation method of arsenic‐containing white rice grains as calibration standards was developed for the X‐ray fluorescence (XRF) analysis of arsenic in rice grains. Calibration standards were prepared by adding 10 g of white rice grains (from Japan) to 100 ml methanol‐containing dimethylarsinic acid corresponding to 2–100 µg arsenic. The mixture was heated, dried at 150 °C, cooled to room temperature, and then stored in a silica gel desiccator. A total of 5.0 g of each calibration standard was packed into a polyethylene cup (32 mm internal diameter and 23 mm height) covered with a 6‐µm‐thick polypropylene film and then analyzed by wavelength‐dispersive XRF spectrometry. The calibration curve for arsenic obtained from the white rice grains containing arsenic showed good linearity over a concentration range of 0.21–5.00 mg kg−1 arsenic. The limit of detection of arsenic was 0.080 mg kg−1. To check the reliability of the XRF method, the concentrations of arsenic in six samples of grain cereals and two samples of flour were compared with those obtained by atomic absorption spectrometry after acid decomposition. The values obtained by both analytical methods showed good agreement. Copyright © 2016 John Wiley & Sons, Ltd.

A rapid and simple method using wavelength-dispersive X-ray fluorescence (WDXRF) spectrometry after in situ solid-phase extraction (SPE) was developed for the speciation and evaluation of the concentration of inorganic arsenic (As) in drinking water. The method involves the simultaneous collection of As(III) and As(V) using 13mm ϕ SPE miniature disks. The removal of Pb2+ from the sample water was first conducted to avoid the overlapping PbLα and AsKα spectra on the XRF spectrum. To this end, a 50mL aqueous sample (pH 5-9) was passed through an iminodiacetate chelating disk. The filtrate was adjusted to pH 2-3 with HCl, and then ammonium pyrrolidine dithiocarbamate solution was added. The solution was passed through a hydrophilic polytetrafluoroethylene filter placed on a Zr and Ca loaded cation-exchange disk at a flow rate of 12.5mLmin−1 to separate As(III)-pyrrolidine dithiocarbamate complex and As(V). Each SPE disk was affixed to an acrylic plate using adhesive cellophane tape, and then examined by WDXRF spectrometry. The detection limits of As(III) and As(V) were 0.8 and 0.6μg L−1, respectively. The proposed method was successfully applied to screening for As speciation and concentration evaluation in spring water and well water.

A rapid and simple method was developed for As determination in drinking water by solid-phase extraction (SPE)/mobile X-ray fluorescence (XRF) spectrometry. A 50 mL aqueous sample was adjusted to pH 3 with dilute hydrochloric acid, and then passed through a Ti and Zr-loaded carbon disk (TiZr-CD) to pre-concentrate the As. The SPE disk was adhered to an acrylic plate with cellophane tape, and then examined by mobile XRF spectrometry. The TiZr-CD adsorbed inorganic As (as As(III) and As(V)) and organic As (as methyl, phenyl and aromatic arsenic compounds) from water. The As calibration curve had good linearity over the range of 0.5–5 μg, and the limit of detection was 0.10 μg (2.0 μg L−1 in As concentration). The concentrations of As in well water samples were determined using the proposed method were similar to results obtained from atomic absorption spectrometry. The proposed method did not require a power supply or a toxic solution and/or gas in any analytical step, therefore it is suitable for the on-site determination of As in drinking water.