The microorganisms play an important role in selfpurification of water and soil environment as decomposers in the ecosystem. Microbial technologies, such as a activated sludge or oxidation pond processes, have been extensively applied to the treatment of industrial and domestic sewages to break down organic wastes. Another type of treatment is based on their ability to remove specific substances such as phosphorus, nitrates and heavy metals. The environmental pollution by toxic metals, especially Pb, Hg, Cd, is a potential hazard to the health and welfare of mankind. Many people in Japan suffered from diseases caused by pollution of heavy metals, such as ache-ache disease and Minamata disease. We feel misgivings about the similar environmental pollution in the developing countries, for the rapidly growing industrial operations would release heavy metals and those metals even at very low concentrations would be concentrated biologically through natural food chains. Microalgae can concentrate metals and transform them into less hazardous forms, and the use of microalgal biomass would offer a potential alternative to conventional methods for detoxification and for recovery of toxic or valuable metals. This review summarizes an information on physiological relations between heavy metals and microorganisms, especially microalgae, and presents some applications of algal biotechnology that has been developed to use microalgal biomass for bioremediation of heavy metals.

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The present review describes the structure of anticholinesterase organophosphates (OPs), which are worldwidely and predominantly used as insecticides, in relation to the poisonous gas (possibly sarin-poisoned) disaster happened recently in Matsumoto-city, Nagano. As evident from the disaster, many OP compounds have caused the severe toxicity and even death in humans and domestic animals. The toxicity, chemical structures, mechanism of action (cholinesterase inhibition), clinical signs and syndromes, antidotes and treatment, and prophylactics of nerve gases and OPs are described and discussed. The general metabolic fates of OP insecticides are also dealt with in this review. Some OPs including insecticides have been known to cause chronic toxicity, particularly delayed-type neuropathy (organophosphorus ester-induced delayed neuropathy, OPIDN), which is currently understood to be due to the inhibition of nerve toxic esterase or neuropathy target esterase. OPIDN still has the merit of further study and thus I describe here in detail, because it contributes to the long-term morbidity in cases of severe acute, or chronic, exposure to OPs.

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Application of wing spot test with Drosophila melanogaster for bio-antimutagen detection was investigated. Firstly, four mutagen exposure methods were compared with Trp-P-2 or IQ, and cellulose powder method was recognized as the most effective. Then, cobaltous chloride, gallic acid and cinnamaldehyde which are known as bio-antimutagens were tested and this method was found very useful as a second screening method for bio-antimutagen between bacterial tests and cancer depression tests with mammals.

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tert-Butylhydroquinone (TBHQ), an antioxidant for edible fats and oil, inhibited nitrosamine formation in the reaction of secondary amines with nitrite under acidic conditions. The inhibitory effect may be due to the loss of nitrite available for nitrosation. TBHQ was oxidized with nitrite into 2-tert-butyl-p-benzoquinone (TBQ), which was active in enhancing nitrosamine formation in the presence of an adequate amount of available nitrite. TBQ readily reacted with secondary amines to form 1 : 1 secondary amine-TBQ adducts whose structures were established to be 2-tert-butyl-5 (and 6)-amino-p-benzoquinones. The adducts may be nitrosated to be transformed into the nitrosamines, or they may catalytically enhance the nitrosamine formation.

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The relationship between the in vivo and in vitro behavior of aluminum (Al) was studied in the presence of food additives and the structurally related compound, maltol, kojic acid, gallic acid, and methyl gallate. Aluminum chloride was administered intraperitoneally into male mice with ligands at a dose of 0.5 mmol Al/kg (Al : ligand=1 : 1 and 1 : 3 molar ratio). When Al was administered with maltol and kojic acid in a 1 : 1 molar ratio, Al was mainly transferred to the liver and spleen by 3 h and the level of urinary excretion of Al was low. When control mouse serum was spiked with Al as Al-maltol (1 : 1) and Al-kojic acid (1 : 1) mixtures in vitro, it was detected in the high-molecular-weight (HMW) fraction including globulin and in the low-molecular-weight (LMW) fraction. The in vivo and in vitro behavior of Al in Al-maltol and Al-kojic acid were similar to those of Al chloride. When Al was injected as Al-maltol (1 : 3), Al-gallic acid (1 : 1 and 1 : 3), and Al-methyl gallate (1 : 1) mixtures, it was also distributed to the kidney within 3 h and the urinary excretion of Al was on a higher level. Aluminum added to control mouse serum as these Al-ligand mixtures in vitro was detected only in the LMW fraction. The results were interpreted based on the stability constants of the Al-ligand complexes.

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Treatment of Staphylococcus aureus cells with a quaternary ammonium disinfectant, didecyldimethyl ammonium chloride (DDAC), induced increase in turbidity of the cell suspension and inhibited the cell respiration. Addition of DDAC also increased turbidity of the suspension of protoplasts, the membrane and cytoplasm fraction, and even the liposome prepared from the cell phospholipid and soybean lecithin. In addition, it enhanced membrane fluidity of the liposome prepared from the cell phospholipid. It is proposed from findings in this and previous papers that the cationic surfactant first causes damage to the structure of the cell membrane which results in irreversible inactivation of all membrane functions.

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Trihalomethanes such as chloroform, dichlorobromomethane, dibromochloromethane and bromoform in food, which might be produced by the treatment of foods with sodium hypochlorite, were determined by the distillation method. The distillation method was modified for the extraction of trihalomethanes from foods containing lipids and/or proteins. Trihalomethanes in the commercially available bean-curd were determined in the range of 19.8 to 53.5 ppb, although they were not detected in ice candy and pickles. The amount of chloroform in the bean-curd increased with an increase in concentration of sodium hypochlorite used for treatment and in storage temperature. The amount of chloroform produced in the Kinu bean-curd was greater than that produced in the Momen bean-curd. In the bean-curd treated with hypochlorite a large amount of trihalomethanes was generated. On the other hand, in the bean-curd treated with chlorine dioxide or chlorite trihalomethanes were hardly generated. This fact recommends the use of chlorine dioxide or chlorite instead of sodium hypochlorite for the disinfection of food. The use of hypochlorite should be prohibited, because the hypochlorite treatment caused the generation of trihalomethanes in food.

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A simple and rapid method for the detection of 12 quaternary ammonium compounds (Suxamethonium, Pancuronium, Benzethonium, Acetylcholine, Bethanechol, Hexamethonium, Propantheline, Methylbenactyzium, Neostigmine, Distigmine, Pyridostigmine and Ambenonium) using thermospray high-performance liquid chromatography (LC)-mass spectrometry was investigated. Each compound was extracted from urine as an ion-pair with bromothymol blue, tropaeolin OO and hexanitrodiphenilamine in dichloromethane. The used LC column was Asahipak GS-320H for aqueous steric exclusion chromatography, and the mobile phase was 100 mM ammonium acetate-acetonitrile (90/10 v/v or 70/30 v/v). The ion source block and tip heater temperatures were set at 300 and 320°C, respectively. The vaporizer control temperature was kept at the temperature of the take off temperature minus 15°C. The recoveries of 12 quaternary ammonium compounds from the spiked urine were 76.1 to 98.6% by ion-pair extraction. The detection limits of these compounds for the simultaneous analysis were 0.5-80 ng/ml by selected ion monitoring mode.

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Air monitoring for examining the mutagenicity and property of airborne particulates at roadside of the 2nd Shin-mei highway in Kobe was carried out. Airborne particulates were collected on glass fiber filters using high-volume air sampler from January to December in 1992. Organic components in airborne particulates were extracted by the ultrasonic extraction method using benzene-ethanol (3 : 1 v/v). The crude extract was extracted with blue-rayon to determine the contribution of the PAHs to the whole extracts. The mutagenic activity of airborne particulate extracts was measured according to the method of Ames et al. using Sallmonella typhimurium TA98 and TA100. Strains YG1021, YG1024, TA98NR and TA98/1, 8 DNP₆ were also used to check the contribution of nitro-PAHs. The extracts of airborne particulates showed positive mutagenic response in both strains, TA98 and TA100, with or without S9mix. The mutagenic activities of blue-rayon extracts to TA98 without S9mix showed approximately 50% of the activities of crude extracts in each month. Mutagenic activities to YG1021 and YG1024 were 3-4 and 5-10 times higher than those to TA98, respectively. On the other hand, the mutagenic activities to TA98NR and TA98/1, 8 DNP₆ were only 18% and 16% respectively of the activity to TA98. The mutagenic activity of airborne particulates significantly correlated with the concentration of airborne particulates and NO₂. Ten selected PAHs and 1-nitropyrene, 2-nitroanthracene and 6-nitrochrysene were detected in HPLC. Total amount of those PAHs and nitro-PAHs accounted for only 10-20% of the observed mutagenic activity of blue-rayon extracts. These results suggested that most of the mutagenic activity in blue-rayon extracts were attributed to dinitrated PAHs which showed remarkably higher mutagenic activity than mononitrated PAHs.

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To examine biological effects of UVA, we investigated effects of UVA-sensitization with hematoporphyrin (HP) or riboflavin (RF) on the hemolysis and lipid hydroperoxide levels of rabbit erythrocytes. We irradiated UVA (365 nm) at r.t. for certain time, and after the end of irradiation measured hemolysis keeping erythrocytes at r.t. or at 0°C. As the result, though erythrocytes hemolyzed almost 100% at r.t., hemolysis was almost 0% at 0°C. It is evident that HP was a much stronger sensitizer than RF. Moreover, we measured contents of hydroperoxide of phosphatidylcholine (PC) and phosphatidylethanolamine (PE), most of which constructed lipid cellular membrane, after or before UVA irradiation by the chemiluminescence-HPLC method. As the result, before hemolysis, hydroperoxide levels per lipid significantly increased after the end of irradiation, compared with control (1.75→4.57 nmol/mg PC. 6.13→12.9 nmol/mg PE, respectively). These results suggest that celluar membrane lipid hydroperoxide which was formed with singlet oxygen produced by UVA sensitization, might be concerned with hemolysis.

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Contact allergenicity of 2-mercaptobenzimidazole (MBI, a rubber antioxidant), methyl 2-benzimidazolecarbamate (MBIC, a fungicide) and ethylene thiourea (ETU, a rubber accelerator) was examined by a modified guinea pig maximization test with the first induction at ⪈5% and the challenge at ⪈5%. Both MBI and MBIC showed no contact allergenicity even at a maximal concentration of the first induction treatment (5%) and the challenge (5%). On the other hand, ETU had contact allergenicity by the first induction at 5 and 0.5%, and the challenge at ⪈0.5 and 5%, respectively. In addition, cross sensitization among MBI, MBIC, ETU and MBI-related compounds was evaluated. Animals treated with ETU for the first induction showed no dermal response against the challenge of MBI. In animals treated with MBI or ETU for induction no dermal response was observed against MBI-related compounds such as MBIC, 2-mercaptobenzothiazole, benzimidazole, benzene, imidazole, 2-mercapto-2-thiazoline, 2-mercapto-1-methylimidazole and thiourea. Exceptionally, guinea pigs treated with MBI for the first induction at ⪈0.5% had dermal response against the challenge of ETU at ⪈0.5%.

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Caproic acid and acetic acid contained in water as aliphatic mono-carboxylic acids were investigated for the decomposition level caused by UV irradiation alone with low presser mercury lump, ozone alone or ozone-UV irradiation. The buffer solutions for preparing sample solutions were studied. Decomposition of 5 mM caproic acid was much slower in the 0.2 M KCl-HCl buffer solution (pH 2.0). The delay of the decomposition thus detected seemed to be due to the consumption of ozone by chloride ion. Therefore, the 0.05 M phosphate buffer (pH 7.0) solution as a medium was most appropriate. Caproic acid contained in water was not decomposed at all by the treatment with UV alone and was decomposed very slowly by the treatment with ozone alone, and the decrease of total organic carbon (TOC) was very low. On the other hand, it was found that caproic acid was very rapidly decomposed by the simultaneous treatment with ozone and UV irradiation, and the removal of TOC was also high. Though acetic acid was particularly difficult to be decomposed, it was almost perfectly decomposed by the simultaneous treatment with ozone and UV irradiation.

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High-performance liquid chromatographic determination for saturated aliphatic aldehydes, specially formaldehyde, acetaldehyde, 1-propanal, 1-butanal, 1-pentanal and 1-hexanal, were studied using a precolumn derivatization reagent acetylacetone. After the selective condensation of these aliphatic aldehydes to form fluorescent dihydrolutidine derivatives, the separation of these compounds was achieved on a ODS column (150×4 mm i.d.) with a linear gradient system of methanol and water (from 50% methanol to 80% methanol in 30 min). The separated lutidine derivatives were detected with a fluorescence monitor (398 nm for excitation and 488 nm for emmission). Three autoxidized unsaturated fatty acid methyl esters and five autoxidized eddible oils were subsequently assayed for 1-propanal (C₃), 1-butanal (C₄), 1-pentanal (C₅) and 1-hexanal (C₆). The peaks of formaldehyde and acetaldehyde were interfered with unknown peaks derived from oxidized lipids. Their detection limits (S/N=2) were 29 ng and 39 ng for 1-propanal and 1-hexanal, respectively. The other carbonyl compounds such as α, β-unsaturated aldehydes and glyoxal derivatives were not interfered by this method.

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