Accurate estimation of human or wildlife exposures is a prerequisite for realistic evaluation of environmental pollution health risks. Comprehensive methodologies should be established to measure and evaluate the exposure precisely. This article reviewed the recent development of exposure assessment concept and the framework of exposure related measurements. Methods of exposure assessment can be categorized as direct, predictive and reconstructive assessments. Each of the methods was explained together with examples of already made exposure assessment such as TEAM study and dioxin exposure from municipal waste incinerator emission.

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The authors surveyed 14 kinds of hydrophilic compound, methacrylonitrile, acrylonitrile, crotonaldehyde, 1-propanol, p-dioxane, 2-hexanone, allyl alcohol, N-nitrosodimethylamine, N-nitrosodiethylamine, N, N-dimethylformamide, N, N-dimethylacetamide, ethylene chlorohydrin, furfural and 2, 3-epoxy-l-propanol, in natural waters at Kitakyushu area. The applied analytical method which was developed in our early work consists of the activated carbon preconcentration method and the GC/MS-SIM measurement. From the results of this survey from 1991 to 1992, 7 kinds of chemical were found at ng/l to μg/l in the seawater and 9 kinds were found in the river water. It was verified that the detected chimicals were allowed to diffuse through the air as well as the water due to their high volatility. p-Dioxane, acrylonitrile, N, N-dimethylformamide, 1-propanol and N, N-dimethylacetamide were detected with a high frequency, because these compounds are used extensively and are persistent in the environment. Among the chemicals detected in this study, p-dioxane was detected in many samples with the highest concentration. As it is carcinogen in animal experiments, it is necessary to successively monitor it's concentration and behavior in the environment.

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The retention time (RT) was accurately forecasted with the program described with GWBASIC on IBM-PC in an arbitrary operation condition.
The discrepancy between the forecast retention time and the measured value was mainly caused by inadequate control of the column temperature and flow rate of the carrier gas.
The theory was induced from the expression of Habgood and Golay.
The forecast theory proposed here was proved to be applicable to actually in the range of practical use.
Tr=k ∗ exp (H/T) +Tr0
Tr; Retention Time
T; Absolute Temperature (°K)
K; Constant related to pressure
H; Constant related to the heat of dissolution
Tr0 ; Constant related to Column dead volume (time)
Approximation solution of three constants of each organochlorine pesticides was obtaind by using the graph function of LOTUS-123.
Approximate solution was calculated based on the data of the RTs in three or more constant temperatures at the fixed column pressure.
It was possible to forecast RT of 16 pesticides with an accuracy less than 0.5%.

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An analytical method was developed for determination of 37 residual pesticides in water effulent from golf links by using capillary gas chromatography/mass spectrometry (GC/MS) . In this paper, the most suitable conditions for capillary GC/MS analysis were detemined.
The separation and sensitivity were found to be good with cross linked methyl silicone capillary column whose column length was around 15 m.
Pesticides in water samples were extracted with methylene chloride and cleaned up by 5 % hydrous silicagel mini column chromatography. The recovery of pesticides were in the range of 84-98%, and the detection limits were approximately 0.05μg/L.

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It is obliged in Japan to monitor the pollution of tap water for 30 pesticides used in golf links. Chemical changes of these pesticides in aqueous chlorine were individually investigated by HPLC, under conditions of 1μg/ml chlorine and at room temperature in dark. Presuming the reaction between pesticides and chlorine to be a pseudo-first-order one, the decomposition rate and the half-life of individual pesticide were calculated.
A great difference in the decomposition rates was observed, and these pesticides were classified into 5 groups according to their rates. The amounts of chlorine consumed per 1 molar pesticide for 3 organophosphorus ones and thiram, all belonging to the group of immediate decomposition, were 5, 7, 3, and 30 moler, respectively. The resulting products from these organophosphorus pesticides were poisonous P=O type substances.
These results on the decomposition of pesticides by chlorine were supported by the estimation of data which Ministry of Health and Welfare of Japan announced on the detection of 30 pesticides both in raw and tap waters.

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Variation of airborne benzo [α] pyrene (B [α] P) concentration in Niigata area were investigated in recent 10 years (April, 1981 to March, 1991) . Airborne dust was collected monthly on a glass fiber filter or a quartz fiber filter for 24 h with a high-volume air sampler at 14 investigated sites (St.1-14) in Niigata Prefecture. B [α] P was determined by the spectrofluorometric narrow base line method or a reversed phase high-performance liquid chromatography.
Geometric mean of B [α] P concentration at all sites was 0.25 ng·m^-3 (0.12 to 0.49 ng·m^-3) or 5.2 ng·mg^-1 (2.8 to 11 ng·mg^-1) . Annual mean concentration of B [α] P decreased in fiscal 1982 (from April to March), and was almost unchanged to fiscal 1987, but increased in fiscal 1988, and then decreased again in fiscal 1989 to fiscal 1990. The B [α] P concentration at the investigated site was affected by surrounding situation, i.e. factories, traffic and/or diesel enginery. B [α] P concentration was higher in winter season than in summer season. The soil dust which was transported from Asian continent by Kosa phenomenon, did not effect the B [α] P concentration significantly.
Mean of daily inhalation intake of B [α] P during the investigated period at all sites was estimated as 0.021-0.033 ng·d^-1·g^-1; mean of B [α] P cancer risk by inhalation was estimated as 0.83×10^-6or 88×10^-6, depending on the cancer unit risk factor adopted.

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Concentrations of airborne pesticides were measured. Sampling sites were located in golf courses in Kanagawa prefecture. Twelve pesticides detected were as followed: isoxathion, chlorpyrifos, diazinon, fenitrothion, echlomezole, chlorotharonyl, chloroneb, tolclophosmethyl, simazine, butamifos, benfluralin and pendimethalin. Air sample was passed through a SEP-PAK silica cartridge column by diaphragm air pump. The pesticides collected were eluted with 5ml of acetone, and determined by gas chromatography equipped with electron capture detecter and flame thermionic detecter. Recoveries of 19 pestisides were 70-100% and those of 2 pesticides were 50-70%. Temperature, wind direction and volatilization rates of pesticides affected to these concentrations in air. Concentrations of diazinon, fenitrothion, chlorotharonyl and isoxathion were higher in daytime and lower in night time. Maximum allowed concentrations of pesticides in air were estimated from relationship between acceptable daily intake (ADI) and LD₅₀. No pesticides were over these concentrations.

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Total Organic Halogen (TOX) and trihalomethanes (THMs) in tap water in Niigata city were measured before and after heating. 66% of TOX, almost all of THMs and 90% of mutagenicity were reduced shortly after boiling. It was shown that most of mutagenicity in tap water results from the organic fraction which volatilizes or is decomposed by boiling. Further boiling neither reduced nor increased the mutagen intensity.
TOX and THMs in tap water of 9 cities in Japan were measured. Maximum, minimum and average of TOX were 131μg/l, 5μg/l and 79μg/l, respectively. Correlation coefficient between TOX and THMs was 0.965. THMs occupied about 30% of TOX. Correlation coefficient of TOX between before and after boiling was 0.959. TOX after boiling occupied about 40% of TOX before boiling.

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Total Organic Halogen (TOX) and trihalomethanes (THMs) in tap water and other 22 indicators in raw water of 7 cities on the River Shinano were measured. Correlation coefficients between the tap water's TOX and the raw water's BOD, TOC or NH₄-N were 0.857, 0.833 and 0.802, respectively. These results suggested that TOX in tap water is related closely to the contaminants in raw water which are produced from our human lives.
Relationship between THMs formation and the retention time of tap water in a water distribution pipe system of a building was investigated. It was found that the amount of THMs increased with the retention time.

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Thianphenicol is one of the anti-bacterials for domesutic animals and fishes. The investigation into the residual anti-bacterials in meat is necessary for public health. In the official method, thianphenicol extracted from meat is analyzed using HPLC/UV absorption at 230nm. However, some compounds interfere with the analysis when the antibacterial in internal organs such as kidney is analyzed. In order to remove the interfering compounds, we improved the preparation method for thianphenicol by modification of the previous method (Kiuchi and Fujimoto, 1991) . The improved method was performed by delipidation with n-hexane, extraction with acetonitril and fractionation by silicic acid column chromatography. The recovery of thianphenicol added to 1 μg/5g hog kidney homogenate, was 70.1%.

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A history and an outline of library search system called as the NIES-MSLS system developed by the authors for an identification of mass spectra obtained with gas chromatographymass spectrometry are described. A unique concept in interpretation of mass fragmentation has been applied to development of presearch. Three independent main search methods are involved in this system. Mass spectral data base has been established in the National Institute for Environmental Studies for more effective library search. Now mass spectra of around 2900 compounds which are sometimes encountered in chemical analysis of environmental samples.

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