Phytoremediation is a promising technology that uses plants to absorb contaminants from the environment. Distinctive advantages of phytoremediation are high public acceptance, enhancing environmental safety and cost-effectiveness. Phytoremediation has been used for the remediation of metal-contaminated soils and has two major techniques: hyperaccumulator uptake and chelate-enhanced phytoextraction. A current concern of phytoremediation is the use of genetic-engineered plants that have ability to highly accumulate metals from the soil. The use of genetic-engineered plants may potentially change plant genotypes due to excessive propagation of these species in ecosystems. For a further possibility, metals accumulated by plants from soils can be recovered through metal extraction processes, which has a potential to be an alternative metal recycling system. Therefore, phytoremediation may be a soil remediation technology involving the conservation of mineral resources for near future.

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The Japan Atomic Energy Research Institute undertook a pilot scale electron beam decomposition of dioxins in the flue gases from the municipal solid waste incinerator at the Takahama Clean Center. The conventional method, following the Japan Industry Standards (JIS) method, takes 2 weeks at least to extract and purify dioxins from the flue gases for analysis by GC/MS. However, using a carbon adsorbent, the time required for the extraction of dioxins was shortened from 16 to 2.5 hours. Further improvements in the clean up process enabled the overall time to be reduced to less than a half of that required by the JIS method. Using this simplified method allows analysts, who are not practiced in the pretreatment of flue gases, to prepare samples for dioxin analysis by GC/MS. The sampling and pretreatment of the flue gases can, with this process, be completed within 4 days with accuracy comparable to the JIS method.

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The new visual expressing methods of PCB, PCDD, and PCDF concentrations were proposed. These methods fulfill the following conditions 1) Concentration differences among isomers are clear. 2) Comparison between samples is easy. 3) Correspondence with chemical structure is easy. 4) It can be expressed compactly. These new methods were applied to the environmental samples. Considering the dynamics of PCBs and PCDD/Fs in the environment, the substitution of chlorine atoms at the 2, 4, 5 positions in PCB, and at the 6, 8 and 7, 8 positions in PCDD/Fs would be key chemical structures.

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Fenitrothion was sprayed by helicopter on the paddy field in Katahigashi, Nishikanbara, Niigata Pref., in Aug., 1997 and Aug., 1998. The concentration of fenitrothion in the atmosphere was measured. The air was trapped into silica gel column, and fenitrothion was eluted with acetone and was determined by FPD-GC. The maximum concentration of fenitrothion at the spray area, 1.0-2.3μg/m³, was observed for 3-22 hours after the application, and the concentration decreased over time. The maximum concentration of fenitrothion outside of the spray area, 0.7-1.8μg/m³, was observed for 22-47 hours after the application. Therefore, the concentration at the outside of the spray area was 1/2-1/10 of the concentration at the spray area. The meteorological parameters at air sampling, geographic parameters and physical chemical parameter were used as the area source plume model (ASPLM) . The emission rate (Q) was calculated by the use of empirical equations with a vapor pressure of fenitrothion and the elapsed time after application. Q, wind speed, distance between air sampling point and emission point, diffusion width and plume height were used as the point source plume equation to calculate the diffusion from a point source in the area source. And the predicted concentration was calculated by summing up concentration diffused from all emission points. It was observed that the predicted pesticide concentrations at the spray area were equal to observed values. The predicted concentration at the outside were slightly lower than observed ones and the prediction error slightly increased with distance from sprayed border line. The predicted values ranged from 1/11 to 11 times of observed them. Therefore, it was proved that the ASPLM was useful for predicting the concentration of pesticides after application on paddy field.

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In order to reduce the mutagenicity of tap water, it is important to investigate the level of mutagenic precursor contained in the tap water source. The Mutagen Formation Potential (MFP) on chlorination is the index of the content of the precursor in water. We measured the MFP of Shinano River downstream water which is used as a tap water source at many points, to evaluate the environmental safety. The measurement was conducted at 6 points from January 2002 to December 2002, monthly by Ames assay usingS. typhimuriumstrain TA100 without S9 mix. The MFP values tended to be higher in winter than in other seasons. On the other hand, only a slight difference was observed among the annual means of the 6 points. The means of MFP at each point ranged from 600 to 1, 000 net rev./l and it was suggested that the mutagenic risk level of Shinano River water was relatively low. We also measured the mutagenicity of 6 tap water samples in the region. Annual means of mutagenicity for each tap water sample ranged from 500 to 990 net rev./l. The values tended to be higher in winter, as was the case with the MFP values.

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We have developed a reliable analytical method for determining trace amounts of bisphenol A (BPA), a suspected endocrine disruptor, in urine samples by use of GC/MS so that daily exposure of human bodies to BPA can be estimated. We administered BPA-d₁₆ (100μg) to volunteers in order to conduct an excretion experiment and found that the BPA was absorbed quickly through the digestive tract and excreted mainly as a glucuronide conjugate into urine, in an amount of almost 100 % in 24 hours. The results suggest that determining the BPA content of urine samples enables estimation of the exposure to BPA.
The results of our analysis of urine from adults show that the average total BPA concentration was 0.82 ng/ml (0.14-5.47 ng/ml, n=91) and that the average free BPA concentration was 0.08 ng/ml (0.01-0.27 ng/ml, n=11) . Also, from a determination of whole-day urine samples, the exposure to BPA was estimated to be 1.68 μg/day (0.48-4.5 μg/day, n=22) on the average.

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Bisphenol A (BPA: 2, 2-bis (4-hydroxyphenyl) propane) released from waste paper during pulping was analyzed in sample solutions prepared by a laboratory pulping equipment. Of 8 kinds of waste paper tested, BPA was detected at a high concentration, 440 mg/l, only in the solution prepared from thermal papers. Therefore, we analyzed sample solutions prepared from 11 thermal papers, used in word processors or facsimile equipment. BPA was detected at concentrations ranging from 170 to 460 mg/l in those thermal papers manufactured in 1999 or before, but at lower concentrations in thermal papers manufactured after that year. Bisphenol S (BPS: bis (4-hydroxyphenyl) sulfone) and BPS-monoP (4-hydroxyphenyl 4-isopropoxyphenyl sulfone) were also detected. These chemicals appear to have been used as color developers for thermal paper in recent years. Also detected were M-terphenyl, 4-benzylbiphenyl, 1, 2-bis (3-methylphenoxy) ethane and benzyl 2-naphtyl ether. These compounds are used as sensitizers in thermal paper.
The estrogenic agonist activities of the chemicals detected in thermal papers were measured using the yeast two-hybrid assay system. Only benzyl 4-hydroxybenzoate and triphenylmethane exhibited activity.

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An analytical method was developed for the determination of tetrabromobisphenol A (TBBP-A), major brominated flame retardant, in water sample by liquid-chromatography/mass spectrometry (LC/MS) . After collecting TBBP-A in water into a solid phase extraction cartridge, it was extracted into acetone. The sample exract in which¹³C₁₂-TBBP-A was spiked as an internal standard was concentrated and redissolved into methanol, and it was subsequently determined by LC/MS. Sufficient amount of [M-H] ^-ion was formed in negative mode of the atmospheric pressure chemical ionization (APCI) and it was used for the selected ion monitoring (SIM) in LC/MS. The recovery, relative standard deviation (RSD) and limit of detection (LOD) were 90.5%, 7.2% (n=5) and 0.1ng/l, respectively. TBBP-A was detected in leachate samples in the range from n.d. (i.e. not detected) to 43ng/l . On the other hand, it was not detected in river water samples. TBBP-A in leachate may be an indicator that can screen landfill sites where waste flame retardant plastics were deposited.

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A simple and rapid determination method of boron concentration in wastewater using an ion-selective electrode has been developed. By adding H₂SO₄and HF to a H3BO₃ solution, H₃BO₃is converted to BF₄^-, which can be measured with a commercial BF₄^-ion-selective electrode. The BF₄^-formation rate obeys the first-order kinetics with respect to the H₃BO₃ concentration. Approximately 1 hour is usually required for the complete conversion of H₃BO₃to BF₄^-. The authors found that by applying the rate equation to a BF₄^-profile in the initial 10 min of the reaction, the original boron concentration in wastewater can be determined from the curve fitting, which leads to a considerable reduction in the measurement time. They also found that NaF can replace toxic HF as a fluorine source in the determination. The proposed method can detect a range of 1-300 mg-B dm^-3without any pretreatments; this range covers the Japanese wastewater standards for boron.

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Advanced water treatment-ozonation and activated carbon filtration-has been in operation at all utilities of Osaka Prefecture since July 1998 and Osaka City since March 2000. It was also introduced in one of the two utilities supplying water to the cities of Kobe, Nishinomia, Ashiya and Amagasaki. A blend of advanced treated surface water (ATSW) from Osaka Prefecture and their own conventionally treated water was supplied to the homes in almost all municipalities in Osaka Prefecture supplies.
We investigated total organic halogen (TOX) levels, as chlorination by-products, in 68 tap waters of 29 cities in Osaka Prefecture and its surrounding prefectures from July to August, 2000. No significant difference in TOX level of tap waters was observed between condominiums or apartments and detached houses. For ATSW, TOX were significantly increased from Osaka Prefectural purification plants to household taps, but the increase in TOX was not found in the case of Osaka City. TOX concentrations in the different type of tap waters were as follows: for ATSW, from 21.9 to 62.2μgCl/l, for a blend of ATSW and conventionally treated ground water (CTGW), from 11.5 to 57.1μgCl/l, for a blend of ATSW and conventionally treated surface water (CTSW), from 30 to 100μgCl/l, for a blend of CTGW and CTSW, from 40.9 to 106μgCl/l, for CTSW, from 32.8 to 171μgCl/l, for CTGW, 60.9μgCl/l. There was no difference in TOX levels of ATSW and a blend of ATSW and CTGW.

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A sensitive method for the determination of tert-butylphenols in environmental samples was developed using GC/MS. Thetert-butylphenols in water were adsorbed on solid phase extraction (ENVI-18) and eluted with hexane. The eluate was dehydrated, and concentrated with nitrogen-gas.
The test-butylphenols in sediment were extracted with acetone, and in fishes were extracted with acetonitrile. Then thetest-butylphenols in acetone and acetonitrile were extracted with hexane. The extract was dehydrated, concentrated with nitrogen-gas and cleaned up by using LC-Florisil for GC/MS determination. Overall recovery rates were 51-87 % for water, 68-87 % for sediments, and 111-125 % for fishes, respectively.
The detection limits were 0.0067 0.011μg/l in water, 0.16-0.66μg/kg in sediment and 0.35-0.79 μg/kg in fishes.

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Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are persistent and toxic contaminants in environments. PCDD/DFs were contained as impurities in herbicides, such as pentachlorophenol (PCP) and chloronitrophen (CNP) used in paddy fields. We have analyzed PCDD/DFs, PCP and CNP in the soil of paddy fields in the Yoneshiro River basin in 1982 and 1984 (1980s), 2000 and 2002 (2000s) . Whereas the levels of PCP and CNP decreased, those of PCDD/DFs did not decrease from 1980s to 2000s. PCDD/DF levels in the basin in 2000s were higher than those obtained in the national survey by the Ministry of Environment and the Ministry of Agriculture, Forestry and Fishery. PCDD/DF concentrations tended to be higher from upstream to downstream in a narrow area such as a tributary. The sources of PCDD/DFs in the paddy fields were identified to be PCP and CNP by a principal component analysis. PCDD/DFs originating from combustion were not identified. We estimated accumulated input and remaining for PCDD/DFs, PCP and CNP in the paddy fields to elucidate the mass balance in the basin. Our estimation revealed that more than 99 % of the herbicides applied to the paddy fields were eliminated, while most of the PCDD/DFs applied to the paddy fields remained. The long-term behavior of PCDD/DFs should be investigated in river basins including paddy fields.

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The distribution behavior of mutagenic compounds formed during carbonization process of cypress wood was investigated by examining the mutagenicity of the carbonized woods, and gaseous and tar-like compounds (by-products) from the wood carbonization. The examination results showed that the mutagenic compounds were mainly transferred into the gas phase, and so these compounds are expected to be direct-acting mutagens causing base-pair substitution. To produce carbonized wood for recycling waste wood, a gas collector for removal of the gaseous compounds from the carbonization is required, and also must be followed by the suitable treatment of the collected mutagenic compounds.

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An analytical method using liquid chromatography/tandem mass spectrometry (LC/MS/MS) has been developed for the simultaneous determination of seven drugs (Clofibric acid, Ibuprofen, Carbamazepine, Naproxen, Ethenzamide, Diclofenac, Mefenamic acid) in environmental water samples. A methanol and water gradient was used for mobile phase of liquid chromatography. Good linearity of the working curves were obtained in the concentration range from 0.5μg/l to 100μg/l for all compounds and the detection limits of all compounds ranged from 0.00076μg/l to 0.0025μg/l The present method has been successfully applied to the determination of drugs in environmental water samples, such as river water and the discharge of sewage treatment plants.

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The concentrations and toxicological evaluation of indoor air pollution by creosote were investigated. In survey of houses where creosote was used as a preservative, total concentrations of seven principal ingredients of creosote ranged from 16 μg/m³to 160 μg/m³. The cell proliferation obstruction rates for the samples extracted from indoor air of the living rooms in three houses ranged from 7.4 % to 15 %. These obstruction rates were higher than those estimated from the obstruction capabilities of ingredients of creosote in the levels found in the indoor airs, suggesting that there are other obstruction factor in indoor air samples. In a model box experiment in which a piece of wood painted with creosote was placed, both creosote concentrations and cell proliferation obstruction rates in air increased by increasing air temperature. No mutagenecity was detected in any of the seven ingredients of creosote within the range of the concentrations used in the experiment. Thus, the bioassay methods and the chemical analysis were both essential to evaluate the toxicity of creosote in indoor air exactly.

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