Narrow Results

In cooperation with the Shanghai Environmental Specimen Bank (SESB) research project and in support of the Shanghai government's comprehensive plan to harness the Suzhou River, we collected water and sediment samples in the every spring season since 1998. The elemental analysis of sediment and water samples was performed by the PIXE technique using the 3 × 2 MeV NEC Tandem accelerator at the Taipei Institute of Physics. The characterization of á and â radioactive levels for water and sediment samples was performed using BH1216, low-background, radioactivity instrument at the Shanghai Institute of Nuclear Research. PIXE results showed that the content of Cl, K, Ca, Cr, Mn, Fe, Zn and Pb in river water gradually decreased with the rising tide. At high tide, their concentrations were minimum, and then once again increased toward the ebb tide. The analysis also demonstrated that the radioactivity of water samples had been gradually decreasing year by year. It was found that the decreasing rate of á radioactivity was a little quicker than that of â radioactivity. Further aspects of environmental data evaluation and assessment are also discussed in detail.

In this study, we carried out PIXE analysis of raw and treated water at five water treatment plants as well as of tap water from several houses located in each supply route. We used a simple fast procedure for preparing thin uniform targets of inorganic components in both soluble and insoluble fractions of aqueous samples in combination with preconcentration of trace heavy metals; that is, Nuclepore filtration targets for coarse particles, preconcentration targets for heavy metal ions and deposit targets for fine particles and soluble major constituents. The target preparation and the PIXE measurement are not time-consuming, and a broad range of concentrations (several tenths of ppb to a few tens of ppm) of 19 elements from Na to Pb is determined simultaneously with a precision sufficient to reveal the elemental distribution in the soluble and insoluble fractions. Tap water quality was examined as a function of elemental distribution in untreated water at the plants. We confirmed the increase of insoluble components of some heavy metals in untreated water taken from river due to heavy rainfall and the elution of Cu, Zn and Pb in drinking water by corrosion of the piping in some part of the water distribution systems.

Phytoremediation is a technology for remediation of contaminated soils. In this study, we used a submilli-PIXE camera to analyze plants and soils from a shooting range. Some heavy metals were rapidly and easily detected in these samples. Element dot-maps of the plant show Cu and Pb accumulated in the epidermis of subterranean stems and the venation of leaves. From these findings, it is possible to map the distribution of heavy metals and to detail their location in the plant, using the submilli-PIXE camera. PIXE analysis is an effective tool for undertaking phytoremediation research.

The aim of this study is to develop a method for monitoring water pollution caused by dissolved sulfides and other harmful elements by means of PIXE offering the advantage of multielemental nature, high sensitivity and speed of analysis for a wide variety of samples. Sulfide ions dissolved in an aqueous sample were converted to insoluble CuS compounds and then collected on a thin organic filter suitable as a backing foil for PIXE measurements. The standard method for scavenging CuS precipitate is founded on an investigation of the pH-dependence of the recovery of dissolved sulfides and the calibration curve covering the concentration range from 10 to 1000 ppb. The recovery-factor of CuS showed a maximum value at around pH 8 although it changed with the intrinsic pH of samples. The recovery factor for pH adjusted to 7.50 was kept constant in a wide concentration range of sulfide ions from 10 to 1000 ppb. The concentration of tens of ppm sulfur compound was detected in both drain water from the industrial waste disposal and in peripheral agricultural water, but the fraction of dissolved sulfide was only about 1%. The low concentration of dissolved sulfides was discussed from the viewpoint of the oxidation condition originated from the soluble and insoluble components detected in samples by PIXE analysis.

Beach rock samples collected from South East Coast of Tamilnadu was analyzed by natural radioactive measurements to detect the presence of radioactive elements. PIXE technique was used to obtain elemental composition of beach rocks. The PIXE analysis was carried out using 1.7 MV tandem accelerators with the energy of 2 MeV protons at Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, Tamilnadu, India. The geochemical behavior of the elements in the region is discussed. The occurrence of the radioactive and non-radioactive elements is discussed for their geological significance. The results were used to assess environmental toxicity of heavy metals and radiation hazard in the study area.

The most important species of chromium (VI) formed in water are anions such as CrO₄^2-, whereas chromium (III) is mainly present in the form of cationic species such as Cr(OH)₂⁺. Pure water and tap water samples were artificially contaminated with mixture of chromium (VI) and chromium (III) standard solutions. Sequential filtration through commercially available Whatman P81 cellulose phosphate paper and Whatman DE81 DEAE cellulose paper was employed for separation and preconcentration of chromium (III) and chromium (VI) in these water samples, respectively. The PIXE measurements of these filter paper samples were performed using 2-MeV proton beams delivered by a tandem pelletron accelerator at Research Laboratory for Nuclear Reactors, Tokyo Tech. The beam current and the measuring time for each sample were 1 nA and 10 minutes, respectively. Instrumental detection limits were 60 ng for chromium (VI) and 120 ng for chromium (III). Detectable range for chromium (VI) and chromium (III) in water were ≧ 10 ppb and ≧ 50 ppb, respectively. For chromium (VI), the detectable range was considerably lower than the maximum allowed concentration of 50 ppb for chromium (VI) in both the drinking water standards and the environmental quality standards in many countries.

A large amount of yellow sand dust from Asian continent transported to Japan by air, affecting traffic, climate and human health. The yellow sand is known as a natural phenomenon, but it is mixed with anthropogenic aerosols over the industrial area in East Asia and causes environmental pollution. In addition, atmospheric turbid phenomena are occasionally observed in spring of recent years over western part of Japan. This phenomenon is caused by the increase in the amounts of fine particles. For a better comprehension of such turbid phenomena, we collected aerosols at Nagasaki. At the same time, particle number concentrations were observed by OPC. The samples were analyzed by an in-air PIXE system at Tohoku University. Time series of elemental concentrations and particle number concentration were obtained. It found that the yellow sand dust phenomenon occurred when coarse particles reached high concentrations, and elemental concentrations of Si, Ca, Fe, Pb and Hg showed similar variations along with that of coarse particles. On the other hand, when fumes or mists were observed, concentrations of fine particles were also correlated with concentrations of S and Zn.

Elemental concentrations in Chinese peanuts have been analyzed and compared with those in Japanese peanuts by means of a PIXE (Particle Induced X-ray Emission) technique with an internal standard method to investigate traces of residual agricultural chemicals or toxic elements in them because frequent detection of excessive agrochemical residues in food imported from China has posed serious health concerns to Japanese people. We prepared the samples by separating the peanut seed into two cotyledons (seed leaves) and an embryo. Significant differences in elemental concentrations between Chinese and Japanese peanuts have not been observed as far as the peanut seeds used in the present measurement are concerned. The concentrations of the several elements in the embryo are higher than those in the cotyledon.

The present work reports the results of a first study of elemental composition in airborne particulate matter (fine and coarse) collected at the Municipality of Centro Habana, Havana City, Cuba, using the PIXE technique. At present, there is not any information available about element contents in airborne particulate matter from this region. A five months sampling campaign was carried out, collecting the samples under an air flux of 20 l/min with a Gent SFU Sampler equipped with a system which allows the aerosol collection in both size fractions simultaneously. A total of 144 aerosol samples were collected. For the PIXE analysis, the samples were irradiated by 2.0 MeV energy protons from a 2MV Tandetron Accelerator. A total of 14 elements (S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br and Pb) were consistently detected with minimum detection limits from 1 ng/m³ to 10 ng/m³ for most of the elements. Enrichment factors were also calculated for both fractions in order to identify the natural and anthropogenic group of elements. The quantitative results obtained have revealed important information that has been used in a first attempt to understand and to characterize the atmospheric pollution of this area.

Concentrations of the chemotherapeutic agent, cis-diamminedichloro-platinum(II) (CDDP) in NFSa fibrosarcoma tumors were investigated using a conventional PIXE analysis on the basis of an internal standard method to study enhancement of antitumor effects caused by proton therapy combined with CDDP treatment. Results of the PIXE analysis showed that platinum concentration of the tumors treated with CDDP at a single dose of 10 mg/kg was 2.0±0.1 µg/g and persisted at the level at least 6 hours after the administration. The present study demonstrated that the presence of CDDP in the tumor caused an enhanced therapeutic effect on tumor growth delay when CDDP treatment was combined with post proton-irradiation in comparison with CDDP treatment alone or proton therapy alone.

The mean concentrations of Al, Si, Cl, K, Ca, V, Cr, Mn, Fe, Zn, As, Br, Rb and Sr have been determined in treated tap water, natural mineral, and untreated ground water of Iraq using non-destructive Proton Induce X-ray Emission (PIXE) analysis in combination with pre-concentration technique. In order to increase analytical sensitivity of the most elements detected by PIXE method, water samples were pre-concentrated by evaporation at 50°C under atmospheric pressure, to obtain dry dissolved solids. A 2.0 MeV proton beam was employed to excite the samples. Certified reference materials (GSP-2) were used in order to verify accuracy of the PIXE technique and the experimental results were in a good agreement with certified values. The concentration of these elements varied from one city to other depending on the geographical locations where the samples were collected. Our results were within the permissible limits reported by Iraqi standards, European standards, and WHO guidelines for drinking water quality. The main objective of this work was to characterize and to monitor the trace elements in drinking water and untreated ground water of Iraq, as well as to provide valuable information about the levels of heavy metallic pollutions.

Ion beam analysis (IBA) is a group of PIXE (particle induced X-ray emission) techniques dedicated to the analysis of material for geological sample of coastal sediment samples. Coastal/Beach samples collected from South East Coast of Tamilnadu were analyzed by PIXE technique and obtain the elemental composition of coastal sediments. The PIXE analysis was carried out using 1.7 MV Tandem accelerators with the energy of 2 MeV protons at Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, Tamilnadu, India. The data analysis is normally done in an interactive mode of GUPIX analytical software computer code. The identified elements are present in the fingerprint X-ray spectrum in the range of ppm to ppb level. Therefore in this paper, introductory results concerning determination of concentration of chosen elements such as K, P, Ca, Ti, Fe, Cr, Co, Zn, Mn, Ni, Cu, Rb, Sr, As, Zr, Hf, Pb and Hg of coastal sediment samples from the east coast of Tamilnadu, India are presented. The validation of the technique is assessed using standard reference material (SRM) NIST 1646a estuarine sediment and the result shows the good agreement with the certified one. The results were used to assess environmental toxicity of heavy metals and radiation hazard in the study area.

Spatial distributions of principal elements in a NFSa fibrosarcoma tumor treated with a vascular disruption agent, AVE8062 (a derivative of combretastatin A-4) at a single dose of 40 mg/kg were evaluated on the basis of particle-induced X-ray emission (PIXE) analysis using a submillimeter-sized proton beam. We found not only potassium and sulfur concentrations at the periphery of the treated tumor but also a ring-shaped calcium distribution in the area between the inner necrotic region and the periphery. These observations were supported by results for quantitative evaluation of elemental concentrations in the tumor samples obtained from conventional PIXE analysis based on the internal standard method. It is suggested that the potassium and sulfur concentrations are related to residual viable cells at the tumor periphery which are commonly observed in VDA treatments whereas the ring of calcium concentration just inside the tumor periphery is possibly derived from hypoxia-induced response.

Particle-induced X-ray emission (PIXE) analysis of Lentinula edodes (Shiitake) mushrooms contaminated with radioactive cesium was performed to study relationships between concentrations of principal elements of shiitake mushrooms and their radioactive cesium levels. After the Fukushima nuclear disaster caused by the huge tsunami on March 11, 2011, we collected five shiitake samples in Marumori town, Miyagi Prefecture, on April 21, 2011. The mean radioactive level of the samples was 228 Bq/kg (the sum of ¹³⁴Cs and ¹³⁷Cs). The preliminary result of PIXE analysis using an internal standard method has demonstrated that shiitake mushrooms significantly collect rubidium as well as potassium. It is suggested that radioactive cesium is accumulated in shiitake just like rubidium during the course of potassium uptake.

Analysis of trace and toxic metals in untreated rainwater has been carried out using nondestructive proton induced X-ray emission (PIXE) in combination with pre-concentration technique. The pre-concentration technique used for this purpose was carried out by evaporation of the rainwater samples at 50°C under atmospheric pressure. Untreated rainwater samples were collected from 10 different locations across Baghdad city, Iraq. The mean concentration values of the elements (Al, Ca, Co, Ti, V, Cr, Mn, Fe, Zn, Br, Rb and Sr) in rainwater samples were determined simultaneously at the parts per billion (ppb) levels. The rainwater samples and certified reference materials (CRMs) were irradiated with 2.0 MeV proton beam from Van de Graaff accelerator. The accuracy of the results was proved by using certified reference materials (GSP-2). The results were compared with the published data, Iraqi standards (IRQ), European standards (EU), and World Health Organization (WHO) guidelines for drinking water quality. The purpose of this work was to obtain the total elemental compositions of rainwater in Iraq.

Particle-induced X-ray emission (PIXE) analysis of Lentinula edodes mushrooms (Shiitake mushrooms) contaminated with radioactive cesium was performed to study relationships between concentrations of alkali elements in the shiitake mushroom samples and their radioactive cesium levels. The shiitake mushrooms were cultivated using radiocontaminated hard wood logs due to the nuclear power plant accident in Fukushima. The significant localization of radioactive cesium was found in the pileus region of the shiitake mushroom from autoradiographic observation. The concentrations of alkali elements in the shiitake sample were measured by PIXE analysis. The PIXE analysis has shown that the concentrations and transfer coefficients of potassium and rubidium in the pileus are much higher than the other parts of the shiitake sample as is the case of radioactive cesium. It is suggested that radioactive cesium is transferred into shiitake mushrooms in a manner similar to potassium and rubidium. The results of this work have shown the possibility to be able to use rubidium as an elemental tracer for radioactive cesium.

The spatial distributions of potassium and rubidium in Lentinula edodes mushrooms contaminated with radioactive cesium were measured using particle-induced X-ray emission (PIXE) analysis by a beam scanning technique with a submillimeter sized proton beam to study relationships in elemental concentration in the mushrooms between radioactive cesium and other alkali elements. The results of PIXE analysis were compared with the spatial distribution of radioactive cesium in the samples measured by an autoradiographic method. Radioactive cesium was not uniformly distributed and strongly concentrated in the peripheral region of pileus of the mushroom while the elemental maps evaluated from PIXE analysis showed that potassium and rubidium are highly accumulated in the same area as radioactive cesium. The present results suggest a common mechanism of the accumulation of alkali elements including radioactive cesium in Lentinula edodes mushrooms.

The concentrations of alkali elements in Japanese green tea leaves were evaluated using particle-induced X-ray emission (PIXE) analysis combined with an internal standard method to investigate the elution of radioactive cesium into green tea using potassium and rubidium. The concentrations of potassium and rubidium of used tea leaf samples were lower than those of unused samples, whereas no significant differences in the concentrations of the other elements were observed between them. In addition, we found a similarity in the relative concentrations between potassium and rubidium although the other elements showed different aspects. These results suggest that it is possible to investigate the elution of radioactive cesium into green tea using potassium and rubidium as substitutes of cesium.

We report an elemental analysis of murine solid tumors treated with cisplatin-incorporated polymeric micelles (NC-6004) to evaluate the concentration of the drug in the tumor tissue using conventional particle-induced X-ray emission (PIXE) analysis, as well as the spatial distribution in the tumor section using sub-millimeter PIXE analysis. The results reveal that the platinum concentration in the tumor treated with NC-6004 was higher than in that treated with cisplatin, whereas no significant difference was found in platinum concentration between NC-6004 and cisplatin samples in the normal tissue. This suggests that NC-6004 can both provide therapeutic efficacy and reduce the side effects caused by conventional treatment using cisplatin. These results show that PIXE analysis is a powerful tool for research into drug delivery systems.

The effects of the vascular disrupting agent AVE8062 on tumor and normal tissue samples were investigated by particle-induced X-ray emission (PIXE) analysis using quantum dots (QDs). We investigated fibrosarcoma tumors in mice, and used kidney tissue as a control. Non-targeted QDs were used to characterize the tissue regions where blood flow is interrupted by AVE8062. We found that the concentration of the QDs in the tumors and kidneys exposed to AVE8062 was lower than that of the control group. Sub-millimeter PIXE analysis (with a beam size of 0.5 $\times$ 0.5 mm²) was used to investigate the spatial distribution of QDs in the tissue samples. We found that the QDs were accumulated in localized regions of the kidney section of the AVE8062-treated group whereas the QDs were uniformly distributed in the control kidney. This suggests that AVE8062 caused blood flow interruption not only in the tumor samples but also in the normal blood vessels in the kidneys.