For the purpose of detecting a micro-quantity of offensive odor substances in fish with offensive odor, mass fragmentography method (GC-mass spectrometry with MID as a detector) was used. Geosmin, furfural, heptyladehyde, hexylaldehyde, and valeraldehyde were examined, because these are known as offensive odor components in water. Furfural and heptyladehyde were detected, but the presence of geosmin, hexylaldehyde, and valeraldehyde in the fish was not determined. All the tested substances were not detected with high-resolution GC-mass measurement (detection limit : ca. 10^-9 g), but furfural and heptylaldehyde were recognized by the mass fragmentography method with MID (detection limit : ca. 10^-12 g). In this study, the samples were concentrated 270 fold (w/v), and concentration in the fish was calculated as about 10^-14 to 10^-15 g. Therefore, it is considered that the recognized substances do not act the main role as an offensive odor substance in the fish.

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Usually the concentrartion of metals in river water in general, except the extremely polluted river water, is in the ppb level and, therefore, determination by the ordinary method, such as the direct atomic absorption spectrophotometry, on sampled water results often in "not detected" in expression. An apparatus consisting of a filter, a constant flow pump, a cation-exchange resin column, and an integrated volume counter, was used for collection of metal ions in natural water. Sample water (about 100-200 liters) was passed through the apparatus at a flow rate of about 10 ml/min. Metal ions adsorbed on the resin were eluted with 6 N HCl solution and determined by atomic absorption spectrophotometry. This method has permitted the determination of a trace amount of metals in public water.

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Performance of a gold film mercury detector and its application for detection of ambient mercury vapor are described. Mercury vapor adsorbed on a thin gold film resistor makes a small resistance change which is detected by a Wheatstone bridge constructed with 4 gold film resistors themelves and IC amplifiers out of which a voltage signal corresponding to the amount of mercury is fed to and displayed on an electrical recorder. The detection limit of the equipment is about 30-50 pg. The Hg vapor calibration curves extended from 0.2 to 200 ng in good linearity are reproducible to within 10% at 0.2-2 ng, and to within 3-4%, relative standard deviation at 4-40 rg. Examinations were made on the selection of a carrier gas which feed Hg vapor into the epuipment, and collection capability of gold wool collector used to pre-accumlate ambient Hg by adsorption and making an impulse Hg signal by desorption all of these factors are important in practice. This gold film resistor method and an atomic absorpion method were compared. The correlation between these two methods showes a good linearity from 2.6 to over 13 ng. Ambient Hg in a room is collected on the gold wool air sampler and detected by this method, and the amount of Hg recorded increased increasing time interval of cellection. The working collection time to obtain a reasonable data of mercury by the air sampler is about 30-60 min, at the air flow rate of 1 liter/min.

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The three components, volatile fatty acids, aromatic hydrocarbons, and phenol, found as the main substances responsible for the unpleasant odor in fish meat, can also act as a toxic substance. In order to know the toxicity of these substances to fish and to reveal the correlation between water quality and toxicity in the area where fish with bad odor lived, median tolerance limit (TLm) tests were made with a carp (Cyprinus carpio L.). The values of TLm found for acetic acid were 69 ppm for 24 hr and 49 ppm for 48 hr, those for propionic acid were 96 ppm for 24 hr and 73 ppm for 48 hr, those for butyric acid were 85 ppm for 24 hr and 65 ppm for 48 hr, and those for valeric acid were 92 ppm for 24 hr and 72 ppm for 48 hr, and those for phenol were 3.6 ppm for 24 hr and 1.7 ppm for 48 hr. In aromatic hydrocarbons, the fish were alive even in 1500 ppm of any of them and TLm values could not be measured. In the TLm tests with a mixture of these substances, concentrations of these substances in the water area in which fish with unpleasant odor lived were several tenths to several hundredths of the experimental TLm values, since the fish can live in such waters. These substances are considered to act as an inducer and the fish living in such polluted waters for a long period of time acquire unpleasant odor.

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The behavior of cadmium absorbed through intestine into living organisms was examined in detail. Metabolism of cadmium such as the interaction in intestinal mucosal precipitate fraction, dynamic behaivior of absorption through intestine to blood, and binding form in serum, liver, and kidney was investigated. Rats administered orally with 1 μCi of ¹⁰⁹CdCl₂ as 1 mg/ml solution were sacrificed after 20 min or 2 hr. The intestine, liver, kidney, and blood were homogenised in Tris-HCl buffer solution, and separated into subcellular fractions by centrifugation. The supernatant of each organ was fractionated by gel filtration over Sephadex G-75. Radioactivity of ¹⁰⁹Cd of the preparation was determined. Most of orally dosed cadmium was bound charactaristically in the intestinal mucosal precipitate fraction, because cadmium bound to the mucosal precipitate could not be isolated by dialysis with Tris-HCl buffer solution or 10^-4M ethylenediaminetetraacetic acid (EDTA) solution but was isolated by 10^-2M EDTA solution. Cadmium was absorbed in the form of free cadmium, which was identified in the liver, kidney, and serum by gel filtration. Cadmium in the supernatant of these organs was present as Fr-I (high molecular weight), Fr-II (metallothionein), and Fr-III (free cadmium). Cadmium in Fr-I decreased with passage of time in all organs, but that in Fr-II increased 2 hr after administration, especially in the liver. There was free cadmium in all the organs 20 min after the administration but not after 2 hr.

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Analytical method for Octachlorodibenzo-p-dioxin (OCDD) in sea foods was studied by ECD-gas chromatography and mass fragmentography. The sample was extracted with hexane in an Omni-Mixer. The concentrated extract was chromatographed over a Florisil column and the column was eluted with 30 ml of hexane and 150 ml of ethyl acetate. The second eluate was purified by chromatography over alumina column, the column was eluted with 100 ml of 5% ether in hexane, and the eluate was used for analysis of OCDD by ECD-gas chromatography and mass fragmentography. Detection limit and minimum amount of OCDD that could be detected by ECD-gas chromatography were 0.01 ng and 0.2 ppb, respectively. Recovery of OCDD added to homogenized samples (fortification level, 0.1 ppm) was 85.3% in average. Detection limit and minimum amount of OCDD that could be detected by mass fragmentography were 0.01 ng and 0.1 ppb, respectively.

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In the determination of formaldehyde, colorimetric method using 4-amino-3-hydrazino-5-mercapto-1, 2, 4-triazole (AHMT) was much better than the conventional method using chromotropic acid or acetylacetone in sensitivity, reproducibility, and simplicity of the analysis procedure. Furthermore, the method was not affected by the presence of sulfite and nitrite ions which are frequently encountered in air and water, and interfere in chromotropic acid method, and acetylacetone method is affected by sulfite ion. For these reasons, AHMT method might be recommnded for the determination of formaldehyde.

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