The effect of reed bed system on the quality of Kahokugata lagoonal water was studied. The effects on water quality were examined by fractionation of dissolved organic carbon, nitrogen, and phosphorus using gel-chromatography. The suspended components of total nitrogen, total phosphorous, BOD, and COD were removed using reed bed system more efficiently than the soluble components of total nitrogen, total phosphorous, BOD, and COD. Based on UV220, UV260, TOC, T-N, and T-P three major fractions were identified by gel-chromatography of Kahokugata lagoonal water. Among them, the 3rd fraction (the lowest molecular weight) decreased after passing through the reed bed, while the 1st one with the highest molecular weight increased. The relative ratio of hydrophilic component increased after the purification of Kahokugata lagoonal water using reed bed system; this suggests that the removal ratio of hydrophobic component was higher than that of hydrophilic component.

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Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in ambient air were analyzed for one year from Sep. 1996 to Aug. 1997 in Matsuyama. Average concentration of PCDD/Fs and TEQ were 13.4 pg/m³ and 0.18 pg-TEQ/m³, respectively. Daily intake of PCDD/Fs by human through the air was estimated to be 2.7 pg-TEQ/ day.
Seasonal change of monthly averaged PCDD/Fs concentration was observed during the sampling period. The concentration was lower in Summer and higher in the rest of the season. Among meteorological factors, including temperature, air pressure and precipitation, only wind speed showed a clear correlation (negative) with the concentration. Relative concentrations of lower chlorinated congeners tended to increase during Summer, probably because of the decrease of dry/wet deposition in Summer due to their higher gas phase proportion in hot Summer season.

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This study was conducted to elucidate the effects of sampling methods, types of vehicle, driving conditions and ambient air conditions on the concentration of PCDFs, PCDFs and coplanar-PCBs (dioxins) in vehicle exhaust gas. The sampling methods of exhaust gas affected the observed concentration of dioxins in vehicle exhaust. The cocentration of dioxins in diesel exhaust was almost same to that in gasoline exhaust and the concentration of dioxins in settled velocity was less than mode-driving conditions. It was speculated that the ambient air conditions might influence on the concentration of dioxins in the exhaust.
The calculated dioxins inventory from vehicles under this study is relatively less than the inventory of dioxins published by environment agency government of Japan.

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A method for simultaneous analysis of pesticides in the atmosphere by means of GC/MS using activated carbon fiber filter paper was examined. The target compounds were 43 pesticides including aerially applied ones. Air was passed at a flow of 10l·miri^-1 through two activated carbon fiber filter papers with a diameter of 47 mm (Toyobo KF Paper P-175) for 7 days. Each sampled filter was extracted ultrasonically with 10 ml of toluene/ethanol (4: 1) for 15 min followed by centrifugation at 3000 rpm for 15 min. The extraction was repeated 3 times. The extracted solution was concentrated to almost dryness, and 1 ml of acetone was added. This acetone solution was analyzed quantitatively with GC/MS. The detection limit for this method was from 0.0001 μg·m^-3 to 0.002 μg·m^-3. In the recovery test, recovery rates were 70-109 % for 36 pesticides. Using this method, variation of pesticides in the atmosphere was monitored in a rural area in Niigata Prefecture. Twenty-two pesticides were detected in the atmosphere at 0.0001 -0.041 μg·m^-3 in median. This method has been successfully used for the monitoring of pesticides in the atmosphere.

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Organophosphorus compounds, which are most toxic components of agricultural chemicals, have generally phosphoester bond (X = P (YR) ₃, X, Y = O, S; R = alkyl group) . In this study, the reactivity for hydrolysis of phosphoester linkage was investigated by estimating the activation energies (Δ E^≠) for the step of nucleophilic attacking of H₂O to P = X (X = O or S) double bond in phosphoester linkage, because that this step is the rate-determining step for hydrolysis.
The clarified points are as follows:
(1) The Δ E^≠ values for the hydrolysis of compounds having P = O double bond are relatively smaller than those having P = S double bond, owing to larger electrophilicity of phosphorus atom in P = O than P = S (sulfur atom (S) is less electronegative than O) .
(2) The sulfur atom in phosphoester linkage generally raises Δ E^≠ value (and therefore, makes less reactive) .
(3) The electron-donating (such as phenyl group) and electron-withdrawing substituents (such as F) on phosphorus atom raise and lower Δ E^≠, which are attributable to larger and smaller electrophilicity of P because of the offset and the increase of positive charge (δ⁺) on P originated in the polarization of P^δ+ = X^δ- double bond, respectively.
(4) The activation energy for intramolecular rearrangement of methyl group converting two ester skeletons (for example, between thiolate and thionate) is extremely larger than that for hydrolysis.
The calculation suggested that the reactivity for the hydrolysis of organophosphorus compounds corresponds to the electrophilicity of phosphorus atom on P = X and the ΔE^≠value consistently changes depending on the electronegativity of X atom (X =O or S) (and consequently, the electrophilicity of P on P = X) and the electron-donating or withdrawing nature of substituents on P

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We investigated long term time variation of dissolved species in the water sampled from the Sagami River and its tributaries. The sampling had been done monthly from May 1993 to April 1999 at 30 sampling sites of Sagami River water system. 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. Chemical oxygen demand, alkalinity, pH, EC were also determined. The data accumulated for 6 years (except Ca, Fe, Ag, W, Tl) were examined using Fast Fourier Transformation (FFT) to extract dominant periodisities, their magnitudes and phases. Clear seasonal variations (12 months period) were observed for many elements at many sampling points especially at down stream area. Aluminum, Cs, V had concentration maxima in summer, while Mg, Mn, Ni, Zn, Mo, U had maxima in winter. On the other hand, Sr and Ba scarcely showed seasonal variation. It can be considered that the seasonal variations may be caused by either anthropogenic origin such as irrigation, wastewater discharge from industry or natural reason such as water temperature, pH, redox condition, water flux, activity of micro-organism in the water. In some cases, we found strong correlation with irrigation condition, water flux (Ni, Mo at down stream area) . In another case, activity of micro-organism could control the variation (Ni at down stream of reservoir, Lake Sagami and Tsukui) . However, we did not find any correlation with pH, and water temperature may not be a main controlling factor. Thus it is difficult to explain the seasonal variations of all elements with single factor. Even the same element at different sampling site may have different factor (s) of variation.

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Performance of a diffusion sampler was evaluated for formaldehyde (HCHO) gases in a small chamber with a constant gas generation system under controlled meteorological conditions (temperature, humidity and wind speed) . The sampler consists of porous polyolefin tube uniformly packed with DNPH coated silica gel as collection media. The relative standard deviation for triplicate analysis of the amount of HCHO collected by this sampler was 4.5 % for 50 ppb. The linear relationship was found between amounts of HCHO collected and exposure time under constant conditions. The humidity and wind velocity have no influence on the collection efficiency of the sampler. And the conversion rate did not show apparent temperature dependence. This method was applied to a preliminary field test in a newly built house. The results showed that 47-51 ppb of HCHO was determined in indoor air as 24h-averaged concentration and agreed to those by active sampling method.

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We have developed a method for the determination of chlorobenzenes in blood by head space SPME-GC/MS. Five ml of blood sample is put into a head space bottle, to which an enzyme is added for proteolysis. The head space of the bottle is sampled by a solid phase micro extraction (SPME) . The SPME fiber is analyzed for chlorobenzenes by GC/MS. This method is excellent in sensitivity and selectivity, easy to operate, and is applicable to actual samples. This is also an environmentally friendly method, for it requires only small amounts of reagents and solvents.
Blood samples were collected from 60 subjects, all of whom are members of Nagano Research Institute for Health and Pollution and their families, and analyzed. In all the blood samples, p-dichlorobenzene (0.4-210 ppb; 14.9 ppb on the average) and HCB (0.07-0. 40 ppb; 0.17 ppb on the average) were detected. p-Dichlorobenzene is considered to have been derived from moth-proofing agents for clothes and odor-removing agents for toilets, whereas HCB is considered to have been derived from food.

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A survey of 73 hazardous air pollutants was performed at 35 sampling sites (including nine air monitoring stations) in Fuji city in August and December 1999. Target compounds were 14 aromatic hydrocarbons (BTXs), 39 polycyclic aromatic hydrocarbons (PAHs), 10 aldehydes and 10 volatile organohalogen compounds (VOHCs) . Main results in the survey were as follows:
1) Benzene concentrations were high along the main street, suggesting that these concentrations were affected by motor vehicle emission.
2) PAH concentrations at specific sites in the city were higher than the other sites. This suggests that PAH concentrations were affected by the specific stationary emission sources.
3) Aldehyde concentrations were high along the north part of the main street in summer, whereas they were high along the south part of the main street in winter, suggesting that these concentrations were affected by wind direction.
4) Chloroform, trichloroethylene and tetrachloroethylene concentrations were affected by the stationary emission sources, such as chemical factories, metal surface treatment plants.
5) The nine monitoring stations were suitably located to get mean levels for various hazardous air pollutants in Fuji city.

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Contour maps of selected 20 compounds were constructed from the results of the survey of hazardous air pollutants in Fuji city, Japan. Relationships between the locations of high concentration areas and those of emission sources were investigated.
The results obtained were as follows:
1) Benzene and formaldehyde concentrations were found to be high along the trunk roads. Contour maps of toluene and acetaldehyde concentrations were similar to those of benzene and formaldehyde.
2) PAH concentrations were predominantly affected by soot concentrations emitted from the specific factories.
3) Trichloroethylene and tetrachloroethylene concentrations were significantly affected by the stationary emission sources. Chloroform concentration was found to be high near the factories of using it. Because emission amount of chloroform is relatively small, other factors may affect chloroform concentrations.

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In this study, the removal efficiency of dioxins (polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and coplanar polychlorinated biphenyls) by the zeolite was investigated by setting artificial zeolite derived from fly ash in the exhaust gas line of a small size incinerator made for demonstration. When model wastes that contains 5 % polyvinyl chloride were incenerated, the concentrations of dioxins in the final treatment gas were 0.30 to 0.51 ng-TEQ/m³N, which were adequately below the regulation (5 ng-TEQ/m³N) . In order to reduce the total dioxins discharged from small size incinerators, the following measures are effective, that is, the removal treatment of dioxins in exhaust gas using the artificial zeolite, non-heating degradation treatment of dioxins in used zeolite and ashes, and regular monitoring of dioxins in exhaust gas using simplified sampling filter.

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Coagulation experiments with aluminum sulfate or iron (II) sulfate, as an inorganic coagulant, and adsorption experiments with activated carbon or activated alumina were conducted in order to find optimum condition for the removal of boron from the wastewater. The following results were obtained from the experiments.
From the coagulation experiments, a removal ratio of 0.95 was obtained by the addition of hydrogen peroxide and calcium hydroxide to the borate-contained wastewater when aluminum sulfate was used and the pH was adjusted to 9. A large amount of the removed boron was considered to be adsorbed on the surface of resulting precipitates since higher concentration of boron was observed at the early stage of dissolution of the precipitate with a diluted HCl solution.
From the adsorption experiments, it was found that activated carbon was capable of adsorbing borate. An adsorption amount of 0.14 mg-B/g-adsorbent was observed when the solution of 10 mg-B/l was in contact with activated carbon at 25 °C for 72 hours, and the capacity is larger than that of activated alumina.

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Mutagenicity of a reference material (RM) was analyzed with Salmonella (TA100, TA98 and YG1024) preincubation procedure under the collaboration of 5 laboratories through 3 years in Japan. The RM was prepared from urban air particle (total 9234.8 mg after the filtaration of 10⁵ m³ air) . After ultrasonication with methylene chloride, the solvent was exchanged to dimethylsulfoxide. The RM was subdivided into 300 brown ampules (each 0.8 or 1.6 ml) at a central laboratory. Ampules were sent to each laboratories, and were storaged at -80°C through the project period (at least 3 years) . No significant variations of the mutagenicity were observed during the 3 years. Repeatability (intra-laboratory variance) of results ranged from 1.5 % to 55 % which seemed to depend on the bioassay conditions (tester strain and metabolic activation), whereas reproducibility (inter-laboratory variance) ranged from 27 % to 69 %. The reproducibility was shown to be similar to the repeatability from the results of two level nested analysis of variance in TA100 and TA98 assays.

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