Recently, environmental and food pollution is becoming a world-wide serious problem, and increasing attention has been paid to the phosphate concentration in environmental water as an indication of the pollution level. This review is concerned with the methods for the determination of phosphate in environmental and food samples by spectrophotometry and ion chromatography. Spectrophotometry by the molybdenum blue method is widely used for the determination of orthophosphate. However, the method suffers some disadvantages as follows : an increase of absorbance with the elapse of time, interferences from reducing substances, and low sensitivity (ca. 1 ppm). To overcome these defects, an improved method for the determination of trace amounts of phosphate was proposed by the present authors. Phosphate is rapidly collected on a membrane filter as an aggregate of molybdophosphate and Malachite Green. The aggregate is dissolved in a small volume of methylcellosolve along with the membrane filter. Absorbance (627 nm) is proportional to the phosphate concentration. The method made it possible to determine phosphate in river water, tap water and mineral water at levels ranging from 0.1 to 150 ppb. Phosphate in water can also be determined by ion chromatography (JIS K0556-1990). Even though the sensitivity (0.5 ppb) of the method is found to be inferior to that of spectrophotometry, the method can provide the information not only on the phosphate content but on other chemical components in samples.

抄録全体を表示

The influence of temperature on the formation and decomposition of ozone by ultraviolet rays from a low pressure mercury vapor quartz lamp was studied. The main spectral lines for the lamp used in formation were 184.9 nm and 253.7 nm, and those used in decomposition were 253.7 nm. The lamps were cylinder shaped, and were 10 W. In the formation experiment, the temperature was changed from 55°C to 550°C (eleven levels), keeping the relative humidity constant. Ozone concentration initially increased, then decreased, as the gas flow rate decreased. During this process, the reversing zones at each temperature were recognized. The concentration decreased as the temperature rose, and the tendency was notable at higher temperatures. When the gas flow rate was low at 0.3 l/min or less, the ozone concentration was low, and it began to decrease greatly at about 200°C. It was extremely low at about 450°C. When the gas flow rate was high at 0.5 l/min or above, the ozone concentration was low, and remained constant up to about 200°C, thereafter decreasing greatly. It was extremely low at about 450°C. In the decomposition experiment, keeping the relative humidity constant, the reaction temperature was changed from 55°C to 275°C (eight levels). The differences between the heating decomposition ratio with and without irradiation by ultraviolet rays were measured. The heating decomposition reaction was recognized at around 100°C, and the decomposition ration rose as the gas flow rate decreased when the temperature was kept constant. The ratio also increased with increase in temperature under constant gas flow rate. It was about 70% at 250°C, 1.0 l/min. Data were obtained on temperature and decomposition ratios at various gas flow rates. The decomposition ratio difference increased as the temperature decreased when the rate of gas flow was unchanged, and also increased with decrease in the gas flow under constant temperature. Above a temperature of 250°C, the decomposition reaction of ozone was advanced mostly by heat. That is, the amount of irradiated ultraviolet rays was almost irrelevant.

抄録全体を表示

A low noise-type air sampler for semivolatile organic compounds was developed, and applied to measure the termiticide concentrations of indoor air. The following results were obtained : 1) This sampler permits to suck air at about 1.2 l/min with a noise level at 32 dB (A). The suction rate tended to decrease as the room temperature increased (1.0%/deg), however in the suction of indoor air for 24 h, the error in the value of air volume remained less than 5%. 2) The recovery rates of chlordanes, diazinon, chlorpyrifos, fenitrothion, tetrachlorvinphos and pyridaphenthion were 80-92% after air suction for 24 h at 25-30°C. 3) The variations in the value of chlordanes concentrations determined by the successive measurement of a living room air for 20 d were 17%. This indicates that the termiticide levels of indoor air could be well determined by this method. 4) The termiticide concentrations of the indoor air were less than 0.2 μg/m³ in some houses which were treated with termiticide on building 2-4 years ago.

抄録全体を表示

The influence of dichlorodifluoromethane (freon 12) on the formation and decomposition of ozone by ultraviolet rays irradiated from a low pressure mercury vapor quartz lamp has been studied. The lamp used in this study was cylinder shaped 15 W and its main spectral lines were 184.9 nm and 253.7 nm. Freon gas was supplied to the annular middle space of a triple structure pipe that had the lamp in its center. Then, with ultraviolet rays irradiating from the lamp, the relationship between chlorine concentration and freon flow rate was examined. Likewise, air with a small amount of freon gas was supplied to the middle space. The intensity of ultraviolet rays (184.9 nm) after passing through the freon layer was also examined. In a further experiment, freon gas was supplied into the middle space and air with ozone whose concentration was kept constant (10 ppm) was supplied to the annular outside space of the pipe. Then, with ultraviolet rays irradiating from the lamp, the relationship between the decomposition ratio and the gas flow rate was examined. The following results were obtained : (1) Ozone is not decomposed by freon alone. (2) Freon is quite able to pass through 253.7 nm wavelength ultraviolet rays, but it hinders the formation of ozone by easily absorbing 184.9 nm wavelength ultraviolet rays. Ozone was not formed when air was mixed with freon gas of over 0.9 vol%. As the freon flow rate decreased, the formation rate of ozone gradually increased, up to 90% in the case of 0.025 vol%. (3) Freon absorbs 184.9 nm wavelength ultraviolet rays, and part of it forms chlorine after being decomposed. The highest chlorine concentrations recognized, in the case of a 0.11 l/min freon gas flow rate, was 900 ppm. The chlorine concentration produced was in proportion to the ratio of freon in the air. (4) After passing through the freon layer, 253.7 nm wavelength ultraviolet rays are able to decompose ozone without hindrance. That is to say, freon itself does not affect the decomposition of ozone by these ultraviolet rays.

抄録全体を表示

The so-called Kosa ("yellow sand") is transported to the Korea Peninsula and the Japan Islands following wind storms above the desert of the Asian Continent every spring. In this study, samples of the rain water during Kosa periods in 1985 to 1988 were collected at Kanazawa, Japan and Seoul, Korea. The concentrations of inorganic ions in the rain water during Kosa periods were compared with those during non-Kosa periods. The pH values of the rain water during Kosa periods were higher than those during non-Kosa periods. The non-seawater-derived concentrations of Ca²⁺, Mg²⁺, Na⁺ and K⁺ in the rain water during Kosa periods were higher than those during non-Kosa periods. The concentrations of nss-Ca²⁺ and nss-Mg²⁺ during Kosa periods at Seoul were higher than those at Kanazawa, but the ratios of the nss-Ca²⁺ concentration to the nss-Mg²⁺ concentration at Kanazawa and Seoul were almost equal. The concentrations of nss-SO₄^2-, NO₃^- and F^- were relatively higher in the rain water during Kosa periods. It was considered that these anions were adsorbed and/or absorbed in the long range transport process of Kosa aerosols. The acidity of the rain water before the effect of Kosa was tried to be estimated by the analysis of chemical equilibrium between the atmosphere and the rain drops.

抄録全体を表示

To examine the possibility of methylmercury (MeHg)-induced damage at the bloodbrain barrier system, male C57BL/6N mice were orally administered MeHg chloride at doses from 40 to 200 μmol/kg of body weight. Although the Hg levels in plasma and blood at 24 h after the administration increased linearly with dosed amount, the increase in the brain levels exceeded that in the circulation levels. The ratio of the brain Hg to the dosed amount increased from 0.443±0.026% in the 40 μmol/kg dosed group to 0.667±0.062% in the 200 μmol/kg dosed group. The Hg concentration ratio of brain to plasma also increased from 1.26 to 1.90. Although some disturbance was expected in the brain uptake system of MeHg for the accelerated accumulation of the brain Hg, brain uptake of ¹²⁵ I-labeled bovine serum albumin and ¹⁴C-L-methionine was not affected by MeHg treatment at all. This indicated that transport systems for albumin- and cysteine-conjugate of MeHg in the brain remained unchanged under the present circumstances. Ultrafiltration analysis revealed that Hg distribution rates in low molecular weight fraction of plasma markedly increased with dose. Glutathione and cysteine conjugates of MeHg were dominant constituents in this fraction. Although plasma cysteine levels increased after MeHg administration, glutathione levels remained unchanged. In contrast, albumin and total SH contents in plasma were markedly decreased in a dose-dependent manner by MeHg treatment. Furthermore, affinity of MeHg for albumin, a dominant MeHg carrier in mouse plasma, was suggested to be lowered by MeHg treatment. These results appeared to indicate that the mouse blood-brain barrier system was strongly protected from MeHg acute toxicity, as indicated by the unchanged protein and amino acid uptake rates and its γ-glutamyltranspeptidase activity. Plasma albumin, however, was shown to be liable to undergo quantitative and qualitative changes by MeHg treatment, thereby resulting in dose-dependent acceleration of the uptake of the low molecular weight Hg conjugate (s) in the brain.

抄録全体を表示

A simulation test method was developed to study biodegradation of chemical compounds by monitoring the decrease in total organic carbon (TOC) of a test medium during incubation with river water microorganisms. Artificial river water containing the test chemical as the sole carbon source with 20 ppm of carbon was used as the growth medium and river water microorganisms which were trapped by membrane filtration (0.45 um) were dispersed in the medium by sonication. The test medium was incubated for 28 d with shaking in the dark. Samples were drawn periodically and biodegradation was determined by measuring the remaining TOC. Biodegradation of 13 chemicals was studied by this TOC die-away method and compared these results with that of cultivation method which was reported earlier. The change in dominating populations during incubation was found to depend significantly on the test chemical when their colony morphology was examined periodically.

抄録全体を表示

An immediate allergic response is caused by a chemical mediator released from basophil and mast cells via a cell degranulation due to a reaction between an IgE antibody, bound with the IgE receptor on the cell membrane, and an antigen. Using cultured cells instead of conventional methods based on histamine release from mast cells, the assay method in the present study permits highly accurate mass screening, since it uses a well-established cell line of rat basophilic leukemia cells (RBL-2H3), and determines by colorimetry the enzyme activity of β-hexosaminidase as an index of chemical mediator release. Effects of food additives on the immediate allergic reaction were evaluated using a newly developed assay system. A total of 100 food additives were investigated for their effects on β-hexosaminidase release from RBL-2H3 cells. Most of the additives showed no action ; zinc sulfate, zinc gluconate, copper sulfate, eugenol, cinnamaldehyde, ammonium persulfate, thiabendazole, ethyl and propyl p-hydroxybenzoates and aluminium sulfates inhibited allergic reaction ; butylated hydroxy toluene and butylated hydroxy anisol promoted this reaction and was attributed to their action of injurying the cells.

抄録全体を表示

A liquid chromatographic (LC) analysis for the determination of seven amines, tyramine (Tym), histamine (Him), phenethylamine (Phm), putrescine (Put), cadaverine (Cad), spermidine (Spd) and spermine (Spm) in soybean paste (Miso), soy sauce (Shoyu) and its products was studied. The amines in the sample were extracted with 0.1N HCl and applied to a column of Amberlite CG-50 and derivatized with dansyl chloride for the application to the liquid chromatography. The LC separations were performed on a Finepak SIL C₁₈S column with an acetonitrile-water elution gradient. The amines were confirmed by TLC for Him and by GC-MS for others with ethyloxycarbonyl derivatives. In the survey of commercial samples by this method, most of Miso samples and ann of Shoyu samples were found to contain these 7 amines. Tym and Him were determined in the range of nd-194, nd-177 μg/g in every kind of Miso, and 95.8-356, 62.8-232 μg/g in Shoyu and its products as average which were higher than the other amines. Shoyu, in general, had higher Him and Tym contents than Miso samples. However the contents of the other amines in both Shoyu and Miso samples were the same levels. It was considered that Tym, Him and Phm were produced by microorganism in a manufacturing process because these amines were not detected from such raw materials as koji (malted rice) and soy beans of Miso and Shoyu. Put, Cad, Spd and Spm were originated from the raw materials, because the contents of these amines in the samples were nearly the same as those of raw materials.

抄録全体を表示

Headspace analysis was employed for the simple and rapid simultaneous gas chromatographic determination of volatile chlorinated hydrocarbons (VCH) in drinking water by dual detection using a semi-wide bore capiliary column (0.32 mm i.d.). For dual detection, an electron capture detector (ECD) and a flame ionization detector (FID), were employed in combination to attain the simultaneous determination at a low parts-perbillion level of 15 kinds of VCH with a single injection. After the equilibration time of 1 h, when 0.5 ml of headspace gas was injected into the gas chromatograph with a splitless injection (0.5 min), the capillary column permitted satisfactory separations for all target compounds without interference by trihalomethane. The sensitivity of detecting cis- and trans-1, 2-dichloroethylene using the FID was about 3-6 fold higher than that using the ECD with the detection limits of 1.0 and 0.7 ppb, respectively. The detection limits of the other VCH were 0.005 (carbon tetrachloride and 1, 1, 1-trichloroethane)-0.7 ppb (1, 2-dichloroethane) using the ECD, which shows a high sensitivity. The coefficients of variation were 3.2-8.8% with good precision and reproducibility.

抄録全体を表示

The dynamic purge trap and simple on-column cryofocusing method with capillary gas chromatography was used to study the basic optimal conditions for determination of the trace levels of volatile halogenated hydrocarbons (VHHs) in an aqueous sample. The pre-concentration method consists of the following 4 main analytical steps ; 1. purging the aqueous sample, 2. trapping at adsorbent, 3. thermal desorption, and 4. retrapping on a trap column (cryofocusing). Using the optimal conditions of the step allowed us sufficient quantitative transfer of VHHs to a capillary column with narrow band width and such good chromatographic resolution with high reproducibility that we were able to successfully apply it to rainwater containing sub ppb levels of mixed VHHs which had very similar boiling points.

抄録全体を表示

A simple and rapid method was investigated for the determination of μg/l levels of lead and cadmium in biological samples, by multichannel graphite furnace atomic absorption spectrometry using ammonium dihydrogen phosphate as a matrix modifier. Bovine whole blood and human serum were selected as biological samples for application. The method has a detection limit of 0.36 μg/l for lead and 0.026 μg/l for cadmium. Concentration of lead 788±14 μg/l and cadmium 13.4±0.1 μg/l in a certified reference material, bovine blood, was in good agreement with the certified value (lead 772±11 μg/l ; cadmium 12.4±0.5 μg/l), respectively. This method was applied to ten sera of normal subject and levels of lead (3.3±1.0 μg/l) and cadmium (0.28±0.11 μg/l) obtained showed reasonable values.

抄録全体を表示

A simple and rapid method for the analysis of inorganic phosphates used for the treatment of vegetables is described. Inorganic phosphates were extracted with water from the vegetable. The extract was mixed with Mo (V)-Mo (VI) color-producing reagent, and the mixture heated at 120-140°C for 10-15min in order to hydrolyze polyphosphates to orthophosphates. The resultant orthophosphates were allowed to react with the Mo (V)-Mo (VI) reagent to from a heteropoly blue complex. Inorganic phosphates were visually semi-quantitative in comparison with a standard solution. When the method was applied to commercial vegetables, it was found that ginger tuber was treated with phosphate more frequently than the other vegetables. This method was applicable to the quantitative analysis by measurement of absorbance at 820 nm.

抄録全体を表示

The microbial degradation of 6 chemicals in river water samples was tested using the cultivation method (Handai Method). Since aniline showed a regional difference, its microbial degradability was investigated in detail using the modified Handai Method to evaluate the possibility of its indication of water pollution caused by organic substances. The results were as follows. n-Butylacrylate was easy biodegradable and Diazinon was degraded to some degree. The microbial degradability of aniline in river water was different. The biodegradation rate increased slowly in unpolluted river water from rural areas, but increased rapidly in polluted river water from urban areas. Additionally, the biodegradation of aniline in these test samples was assumed to tend to be slightly higher in summer than in winter. This suggested that the microbial degradability of aniline in urban river water could be an indicator of water pollution because of the close correlation with the degree of water quality.

抄録全体を表示

Metabolisms of chlorides of 4 kinds of rare earth elements, i.e. dysprosium chloride (DyCl₃), europium chloride (EuCl₃), ytterbium chloride (YbCl₃) and yttrium chloride (YCl₃), were investigated in rats administered orally by a single dose. Male rats of Wistar strain, weighing 160-210 g, were used in the experiments. The experiments were performed by use of 3-4 rats for each group. The rats were fasted overnight before the experiments. The rare earth solutions of low dose (100 mg/kg/5 ml as rare earth elements) or high dose (1 g/kg/5 ml as rare earth elements) were administered orally, and the excretion of the rare earth elements in the feces and urine and the distribution of the rare earth elements in the whole blood, liver, spleen, bone and kidney were investigated. The four kinds of rare earth elements i.e. Dy, Eu, Yb and Y in the feces, urine or various organs were measured by the wet digestion method by using HNO₃ followed by ICP-AES. In the rats administered low dose, 92.0-98.4% of the administered rare earth elements were excreted into the feces within 4 d after the administration ; Similarly, 93.9-98.4% of the administered rare earth elements were excreted into the feces within 7 d after the administration in the rats administered high dose. None of the rare earth elements were detected in the urine. None of the rare earth elements were detected in the whole blood, liver, kidney, bone and spleen in the rats administered high dose or low dose. Therefore, it was suggested that DyCl₃, EuCl₃, YbCl₃ and YCl₃ were scarcely absorbed from the gastrointestine and excreted into the feces within 7 d when administered orally by a single dose.

抄録全体を表示