With the progress in culture and technology, the production of a large amount of various chemicals contributed to the improvement of human life markedly. On the other hand, it is growing to be a new problem that these chemicals threatened our health. By coping with this new problem, making the parameters as the degradability, the accumulation potential and the toxicity of the chemicals, a clue to the decision of the standard, it is required to assess the risk of these chemicals, and the regulation came to be needed by all means. The degradation and bioaccumulation tests for the assessment of the risk of the chemicals are required for the simulation of the degradation and the accumulation originated in the natural environment. In this article, some recent studies will be introduced on the photodegradation and biodegradation tests for the assessment of the risk of chemicals.

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In this study, mutagenic potential of nine main surfactants after activation with various liver homogenates (S-9) was examined by using Salmonella typhimurium TA98 and TA100. Polychlorinated biphenyls (PCB), phenobarbital (PB) and 3-methylcholanthrene (3-MC) were used as inducers, and the S-9 fractions of livers of rats, hamsters and guinea pigs were used for this test. Further, mutagenicity of these surfactants in the presence of norharman (comutagen) was also examined. It was suggested that no surfactants used in this study were mutagenic on the strains of TA98 and TA100 in this test systems.

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Cd-binding proteins were purified from the bone of male rats injected with CdCl₂ for 21 days. The femur was excised and lyophilized after removal of the marrow and extranious tissue. The cancellous bone (epiphysis and metaphysis) was obtained from the femur, ground to fine powder, and used for the analysis of metal such as Cu and Cd and Cd-binding proteins. The cancellous bone powder was suspended in Tris-HCl (pH 8.0) and centrifuged at 105000×g. The supernatant fraction was sequentially applied to columns on Sephadex G-75, Bio-Gel P-10 and DEAE Sephadex A-25. Two Cd-binding proteins were purified. Cd, Cu contents and amino acid composition of Cd-binding proteins were examined. Both purified Cd-binding proteins contained 3-4μg Cd/mg protein, 8-9μg Cu/mg protein, and 2-4 mol % cysteine residue. UV absorption spectra of both Cd-binding proteins were different from those of metallothioneins. These results showed that Cd-binding proteins were different from hepatic metallothioneins. From the experiments by the use of normal rat, it is indicated that there might exist some proteins corresponding to Cd-binding proteins.

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Paraffine hydrocarbons are thought to be good marker compounds for the marine pollution by petroleum, although their natural occurrence in marine organisms and their distribution along the food chain have not been clarified. Tissue contents of paraffine hydrocarbons in sardine, anchovy, horse mackerel, gray mullet, ayu and eel were studied by an improved gas liquid chromatography procedure. Their contents in fish meal and visceral tissue were estimated separately, and the result showed their uniform distribution per tissue lipid. The presence of n-hepatadecane in some phytoplanktons, which are known to be food of sardine, suggests that the origin of paraffine hydrocarbons in the plankton feeder is the phytoplankton on which they feed. Similar relations between horse mackerel and zooplanktons are also inferable from concomitant occurrence of pristane in both planktons and their predators.

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A colorimetric determination of ethylene oxide (EO) and a trapping procedure of residual EO in medical devices were studied. In the trapping procedure, EO-sterilized samples were introduced into a heating chamber and heated at 70°C under nitrogen gas flow at 100 ml/min for three hours. The desorbed EO was trapped by two impingers in series, which contained 10 ml of 5 N sulfuric acid solution, and the impingers were allowed to stand for one hour at room temperature. The aliquots of the contents were collected from each of the impingers, adjusted to pH 5 and used as test solutions for EO determination. In the colorimetric determination for EO, 4 ml of trisodium paraperiodate solution acidified to pH 5 were added to the test solutions and allowed to react for 30 minutes at room temperature. To this, 2 ml of 3-methyl-2-benzothiazolinone hydrazone hydrochloride solution were added and allowed to react for 30 minutes at room temperature. Further 30 ml of mixed solution of ferric chloride and sulfamic acid were added and after 10 minutes the solution was diluted to 100 ml with water. Absorbance was measured at 628 nm. EO recovery of 98% was obtained by using this colorimetric determination and trapping procedure.

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This paper deals with a selective spectrophotometric determination of dibucaine and procaine, local anesthetics, by using thermochromism of ion-associate. Tetrabromophenolphthalein ethyl ester (TBPE) is an excellent extraction reagent for quaternary ammonium ions and amines. TBPE forms red or blue ion-associates with amines or quaternary ammonium ions. Of these ion-associates, the red extract shows a reversible thermochromism. The rate of decrease of the absorbance with temperature change (ΔA/Δt) is proportional to the concentration of the amine in the aqueous phase (ΔA=A_25°C-A_50°C, Δt=50°C-25°C). Consequently, a straight line was obtained in the concentration range (1-5)×10^-6M dibucaine and procaine in the final aqueous solution, with ΔA/Δt as the ordinate and the concentration as the abscissa. Though the ΔA/Δt value of TBPE-dibucaine and -procaine associates were somewhat affected by ΔA/Δt of (5-10)×10^-7M each quaternary ammonium salt, a good recovery could be obtained by subtracting the ΔA/Δt value of each salt measured previously from the ΔA/Δt value of the mixture. This method is useful for the determination of amines added to the human urine.

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After feeding broiler with a feed containing 0.0125% of clopidol (3, 5-dichloro-2, 6-dimethyl-4-pyridinol) in the same manner as poultry farms, the distribution and accumulation of clopidol in several organs and tissues and the excretion of clopidol into excreta were investigated. On the first day after the administration of clopidol, clopidol was very quickly distributed in all of the organs and tissues, and the amount of clopidol distributed was the highest in the liver, followed by kidney and the lowest in fat. From the first day untii the fourth week after the start of the clopidol administration, the concentration of clopidol in each organ or tissue was almost constant, liver (7.9-9.8 ppm), kidney (6.3-8.9 ppm), plasma (3.2-4.7 ppm), breast muscle (3.1-4.6 ppm), intestine (2.2-4.9 ppm), intestinal content (3.9-5.2 ppm) and fat (0.30-0.78 ppm). And the amount of clopidol found in excreta was in the range of 13.4% to 51.1% of the intake. After the stop of the clopidol administration, the concentration of clopidol in each organ or tissue decreased rapidly. It decreased below 0.01 ppm within six days in intestine and intestinal content, and within four days in other organs and tissues. The amount of clopidol in excreta decreased rapidly, too. The biological half lives of clopidol in broiler organs and tissues were found in the range of 9.7 h in liver to 32.0 h in fat.

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It is stipulated by the Ministry of Welfare to use carbon blacks of channel type which are free from Benzo[a]pyrene (BaP) as materials for cosmetics. But BaP is absorbed by carbon blacks so securely that it is not extracted easily with usual organic solvents. This paper describes simple determination method of BaP in carbon blacks. The 100 mg of carbon black was extracted for 5 minutes with hot 1-chloronaphthalene : monochlorobenzene (1 : 1) with shaking. BaP in the filtered solution was determined fluorometrically at 409±3 nm (Ex. 390 nm) by the use of baseline method. Since recovery of BaP added to the carbon blacks was still low because of BaP absorption and coexistent substances, the standard addition method was used to increase the accuracy. The possible intervention of 11 polycyclic aromatic hydrocarbons (PAH) in this method was studied, which may be coexistent in carbon blacks. As the result it was found that benzo[g, h, i]perylene and benzo[k]fluoranthene were added to the BaP figure if in coexistence, while all the other PAH did not affect the determination. When these two hydrocarbons coexisted, a figure could be drawn according to the ratio of the peaks height of their fluorescence spectrum patterns, which could be used to adjust the measurements and obtain nearly precise BaP values. The BaP content of carbon blacks specimens ranged from ND-5.6 ppm for both types of carbon blacks. It was worth mentioning that 209 ppm of BaP was detected in the soot from burned kerosene.

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To clarify the metabolic fate of fenitrothion at low concentration, the detoxication of fenitrooxon (FO) which will serve as an integral part of the metabolic conversion of fenitrothion was investigated. FO at concentration around 10^-6M reacted with mouse liver homogenate and disappeared immediately. This occurred mostly in the soluble fraction of mouse liver, and was dependent on glutathione (GSH), and the only metabolite detected was desmethyl-FO. On the other hand, since hydrolysis by arylesterase (AEase) did not occur, 4-nitro-m-cresol was not detected. These facts reveal that, at such low concentration, FO is detoxified solely through desmethylation reaction catalyzed by GSH S-transferase (GTase). The Km and V_max values of both GTase and AEase for FO are also consistent with this reaction mechanism, i.e. detoxication of FO at higher concentration may be attributable to both GTase and AEase, but at low concentration only GTase will be responsible.

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