This paper reviewed the chemical and physical treatments and the hybrid treatments, in which chemical or physical treatments are combined with bioremediation, as purification technologies for polycyclic aromatic hydrocarbons (PAHs) -contaminated soils. Good PAHs removal efficiency could be obtained by the chemical treatment (i.e., Fenton oxidation, UV degradation, and ozone oxidation) or physical treatment (i.e., surfactant or solvent washing) . The laboratory studies showed that the hybrid treatments achieved the same degree of efficiency using less amount of the solvent or oxidant compared with the unit treatments.

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Brominated flame retardants (BFRs) are used in plastics, rubber, textiles and other casing materials to prevent fires. As well as organochlorines, some BFRs are hydrophobic, persistent and bioaccumulating. BFRs have been identified almost everywhere in the environment. The measurements for PBDEs, representative of BFRs were reported, including in ambient air, indoor air, sediments, fish, birds, mammals, human milk and adipose tissue. Researches on temporal trends with biological samples demonstrated that those results reflect an increase in industrial usage of PBDEs.
PBDD/Fs are often formed in the process of manufacturing BFRs such as PBDEs, bromophenol, tetrabromobisphenol A (TBBPA) etc., and of the combustion of wastes, BFR contained materials or circuit boards. But enough researches have not been done about the toxicity, environmental fate and transport of PBDD/F. Therefore, environmental problems connected with PBDD/Fs are not clear.
This paper briefly reviewed the most recent data on usage, toxicity, metabolism, bioavailability, environmental concentration, fate, time trend and human exposure concerning BFRs and PBDD/Fs.

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Behavior of thiobencarb and mefenacet in paddy field, and the water management for outflow control were investigated. A correlation was found between the amount of adsorption to soil and water depth. The soil adsorption ratio of thiobencarb is about 90% at the 0.8cm water depth, but less than 60% at the 3.2cm water depth. Twenty-three percents of thiobencarb adsorbing to the soil comes out to the water when thiobencarb in water is removed. Mefenacet is hold less on the soil as the water depth increases. However there is not such a clear tendency as in the case of thiobencarb. More than 95% of mefenacet is adsorbed at the 3.2cm water depth and not desorbed from soil.
The three following points are mentioned as a measure to outflow mitigation.
1) Avoid deep water management for herbicides to promote adsorption to soil.
2) Do not move flooded water for at least 4 days after application.
3) Put stopping drain of a paddy field into practice for 14 to 20 days until the water concentration of herbicides becomes low.

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Historical trends of hexachlorobenzene (HCB) in sediment cores were simulated using the emission estimate and the dynamic multimedia environmental fate model. Emission sources considered were as follows: impurities in pesticides (pentachlorophenol (PCP), pentachloronitrobenzene (PCNB), dimethyl-tetrachloroterephthalate (TCTP) ), incineration of HCB containing waste from tetrachloroethylene production, and incineration of municipal solid waste. The simulation results were compared with the measured trends of HCB in sediment cores taken from Lake Biwa and Osaka Bay. Delayed arrival of HCB in the sediment partly explained the difference between the emission trend of HCB and the measured sediment core trend. The difference in the time trend between Lake Biwa and Osaka Bay seems to reflect their different sources and pathways of HCB emission.

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In order to treat PCB contaminated equipment so that they are rendered non-toxic, the attached and or impregnated PCBs must be removed. The Vacuum Thermal Recycling (VTR) method has been demonstrated of its effectiveness to remove PCBs from such impregnated materials. However, decrease in efficiency was suspected due to subsequent adsorption of remaining PCBs into the carbonized material. Therefore, optimization of VTR conditions was conducted in the following two methods.
First, insulation oil that behaves like PCBs were used in the tests to clarify the separation behavior of PCBs from PCB impregnated material. A removing efficiency of above 99.9 % could be achieved between the heating temperatures of 200-270°C. On the other hand, between the heating temperatures of 270-400°C, the remaining amount of insulation oil had increased and it became clear that thermal decomposition of insulation paper has a big influence on the remaining amount of insulation oil. Because of thermal decomposition, paper carbonizes and acts like activated carbon. Therefore its adsorption capability increases and causes a re-adsorption, which has a big influence on the remaining amount of insulation oil.
In the second stage, tests were conducted using real PCBs impregnated paper. The results showed that the behavior of PCBs is similar to that of insulation oil. At 400°C, some re-adsorption of PCBs occurred on the sample. To prevent this re-adsorption, nitrogen gas was purged after heating, to dilute gaseous PCBs that still remained inside the furnace. This method was very effective. The residual PCBs in the insulation paper was reduced from 20 mg/kg to 0.15 mg/kg.

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The following two methods were developed to study the cause of pollution by mineral oils in surface water and groundwater. (1) Surface water sample was extracted with pentane and analyzed with GC/MS after concentration. Gasoline and kerosene were identified from the elution pattern of n-alkanes. The peak area ratios of n-alkanes to dimethylanthracene or trimethylanthracene were used to distinguish light oils from heavy oils. (2) Groundwater sample was analyzed with purge and trap method combined with GC/MS. Aromatic hydrocarbons having small solubility such as benzene, toluene, trimethylbenzene, naphthalene were used to distinguish gasoline, kerosene, light oil from heavy oil.
The examples applied these method to a river water pollution by heavy oil and well water pollution by gasoline and heavy oil were shown.

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A simple method of assaying phosphatase activity in soils from tidelands was developed. This method is based on the colorimetric estimation of phenolphthalein release from phenolphthalein phosphate. Both the colorization of the product and termination of the phosphatase reaction occur at the same time by adding an alkaline phosphate solution to the reaction mixture. Phenolphthalein has an absorption maximum around 550 nm with a higher molecular extinction coefficient than that of p-nitrophenol commonly used in a conventional phosphatase assay.
A blank value was obtained by adding the alkaline phosphate stop solution to the reaction mixture prior to the substrate addition. This value included the absorbance of the colorimetric substance derived from soils and any phenolphthalein spontaneously liberated from the substrate. Thus, the absorbance caused by the actual enzymatic reaction can be easily calculated by subtraction of the blank value from the total absorbance after the reaction.
In this assay, we employed a new soil unit, “packed volume”, which means the volume of tideland soil after centrifugation at 650 g. By measuring the compression ratio of the soil by centrifugation, the obtained specific activity of a packed soil can be easily converted to the phosphatase activity value in the tideland soil in the native state. Most phosphatase activity and ATP were present in the tideland sediment soil fraction. These results suggest that the present method is useful for the practical estimation of phosphatase activity of a bentotic environment and for comparison of the phosphatase activity among various tidelands.

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Gaseous α-chlorinated ether, as an oxidized, chlorinated organic compound, is suspected of being harmful to human health and the environment. Mutagenicities of five gaseous α-chlorinated ethers were measured by a gas-exposure method using five strains belonging to Escherichia coli and Salmonella typhimurium, which were exposed to the ethers in a gasexposure apparatus. Consequently, E. coli WP2uvrA/pKM101 was found to have the highest sensitivity to mutagenicities of the ethers with S9mix condition. These mutagenicities were slightly detected by E. coli WP2uvrA, but they were hardly detected by S. typhimurium TA98, TA100, and TA1535. These mutagenicities were stronger in the order of bis (chloromethyl) ether (BCME) > chloromethyl methyl ether (CMME) > chloromethyl ethyl ether (CMEE) > 1, 2-dichloromethyl ether > α, α-dichloromethyl methyl ether (DCMME), irrespective of S 9 mix existence. The number of revertant colonies (revertants) in BCME reduced with an increase of its concentration after reaching a peak. At higher concentration, revertants in CMME resulted in the highest level among those in respective ethers. With still higher concentration, the level of revertants in CMME was also reduced. At that concentration, revertants in DCMME and revertants in CMEE had the highest levels without S9mix condition and with S9mix condition, respectively.

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A type of umu test method that utilizes new bioluminescent bacteria has been developed. The method does not use any reagents and is able to simultaneously examine many samples with a 96-well plate. Thus the method is simple compared with the conventional umu test. The bacteria used for the method is Salmonella typhimurium TA1535/pTL210 that was transformed to generate luminescence induced by the expression of SOS gene caused by DNA damaging agents. As a result of examinations for the best reaction conditions, the highest and the most stable intensity of bioluminescence was obtained at the reaction conditions of 30°C and 180-240 min. From the results of comparison with the conventional umu test using 9 kinds of typical mutagens, the method showed satisfactory dose-response curves and its sensitivities for the test compounds were 1.6 to 33 times higher than those of the conventional umu test. In addition, in order to confirm the applicability to actual environmental samples, extracts of sea sediments and soils were examined by the method with or without S9. All of them showed genotoxicity only with S9. Their intensities of genotoxicity corresponded with total concentrations of chemicals that were determined by GC/MS. From these results, it was confirmed that the method is useful for evaluating genotoxicity in environmental samples.

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In this study, we investigated the extraction efficiencies of trace polychlorinated biphenyls (PCBs) by Soxhlet extraction from charcoal, originally an insulation paper treated by the Vacuum Thermal Recycling (VTR) process, and activated carbon, used as filter for adsorbing PCBs in the off gas during the VTR process.
Toluene, benzene and dichlorometane were found to be equally efficient for the extraction. PCBs were extracted satisfactorily by Soxhlet extraction for 16 hours (6 cycles/hr) from two charcoals and an activated carbon samples.

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The separation of copper (II) and nickel (II) was investigated by a surfactantgel extraction method. In the presence of nitrilotriacetic acid (H₃NTA), by the addition of potassium ethylxanthate (KEtX) to solutions including copper (II) and nickel (II), nickel (II) remained as NTA complex in aqueous phase while copper (II) was extracted as EtX complex into a surfactant phase of sodium dodecylsulfate (SDS) . This method was applied to the separation and recovery of metals in an alloy consisting of 30 % copper, 66 % nickel, 1.9 % iron and 1.6 % manganese. Extracted copper complex was decomposed by the addition of hydrochloric acid. Copper was back-extracted from the SDS phase and was recovered in aqueous solution. The bromine water was added to the separated aqueous phase in which nickel, iron and manganese remained. Iron and manganese was excluded from the solution as precipitates by the oxidation with bromine.

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To detect the volatile chlorinated organic compounds, trichloroethylene (TCE) and tetrachloroethylene (PCE), by the liquid Bacillus subtilis rec-assay method, the following improvements were conducted: 1) The interaction between the chemicals tested and the B. subtilis strains (H17 [rec⁺] and M45 [rec^-] ) was conducted in sealed serum bottles, thereby avoiding evaporation of the chemicals tested. 2) The survival ratio, a significant indicator of lethal sensitivity for B. subtilis, was measured on the basis of viable cell count instead of turbidity.
With TCE, there was no difference between the survival ratios of H17 and M45. However, a difference was detected with PCE, and PCE showed the potential to damage DNA. Moreover, H17 and M45 were more sensitive to lower concentrations of PCE in the improved method than in the conventional method.

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We investigated long-term time variation of dissolved species in the water sampled from the upper stream of Sagami River and its tributaries. The sampling had been done monthly from May 1993 to April 1999 at 14 sampling sites of upper stream of Sagami River water system (Katsura River) . Twenty-four major to trace elements (Li, Mg, Al, Ca, V, Mn, Fe, Co, Ni, Cu, Zn, As, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, W, Tl, Pb, U) were determined using conventional Q-pole ICP-MS with direct nebulization. Electric Conductivity, pH, water flux (from April 1995) were also determined. Long-term interannual trends of dissolved species were examined for the data accumulated for 6 years by 12 months moving average.
Water qualities of uppermost stream area were generally constant and mostly controlled by spring waters, which are located around Mt. Fuji. However, in 1998, some elements such as V Rb, Cs were depleted temporally, which may be caused by dilution effect of over flow from Lake Kawaguchi and Lake Yamanaka.
On the other hand, in the small creeks with minor influence of spring waters, many elements such as Ni, Zn, Cd, Sb showed long-term trends. These trends may be caused by either factory or mining wastewaters. Moving averages of some elements, like V, As, Rb, showed concentration maxima during 1995 to 1996. These trends may correlate with water flux.
In the tributaries of Katsura River with wider catchments, many elements such as V, Mn, Rb, Cs showed seasonal variations. The moving averages of most of the elements were generally constant, however, Mg, Ca showed slight decreasing trend and correlated with water flux. In some cases, Co, Ni, Mo etc.showed spiky increases indicating point source origin.
Because intake and discharge of water utility for electric power plant, water quality of mainstream of upper area alters depending on sampling sites.

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