Toxic blooms of cyanobacteria (blue-green algae) have been detected in freshwater lakes all over the world. Blue-green algae has most often been involved in poisoning of animals, but has also been implicated in human health problems.
The toxic Microcystis, anabaena and Oscillatoria produce low-molecular-weight toxins, which have been shown to be cyclic heptapeptide named microcystin.
The aim of this review is to summarized the current information regarding the chemistry, toxicology and behavior in environment of microcystin.

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Concentrations of volatile chlorinated hydrocarbons (VCHs) in atmosphere were investigated in 1990 to 1991 by GC/MS using a wide-bore capillary column and behavior of these compounds was studied. Atmospheric concentration levels of VCHs in rural district were around one tenth compared with ones in industrial district or indoor. Relationship between atmospheric VCHs concentrations and meteorological parameters or other pollutants concentrations which were measured with automatic instruments were investigated and it was clarified that variation pattern of VCHs concentrations in atmosphere was similar to that of nitrogen oxides (NOx) . Also, this study showed an essential pattern of daily and seasonal variations.

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Simultaneous Quantification Method of organochlorine pesticides by gas chromatography (GC) using good separative capillary columns and⁶³Ni-ECD was studied. Twenty-one organochlorine compounds including DDTs, HCHs, chlordanes and dieldrin analogues, all of which had been reported to pollute environmental samples, in addition to two kinds of phthalic acid esters often contaminating sample in laboratory were separated by 100% dimethyl polysiloxane (DB-1^TM) capillary column.
Concentrations of all the pesticides in food could be accurately determined by using internal standards (IS), δ-HCH and o, p'-DDD, for the reason that these compounds had been seldom detected in various food. Coefficient of variation (percent relative standard deviation) for the peak areas of these pesticides assayed in repeated injection to GC resulted into the range from 0.68% to 4.73% when the areas were corrected on the basis of the magnitude of ISs areas, and into the range from 4.44% to 6.27% when uncorrected by the IS.
The elution pattern of the twenty-three compounds mentioned above in 14% cyanopropylphenyl-86% dimethyl polysiloxane (DB-1701^TM), and in 50% trifluoropropyl-50% methyl polysiloxane (DB-210^TM) capillary columns were also described in the text.

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2, 4, 4'-Tricholoro-2'-hydroxydiphenyl ether (Irgasan DP300) (I) and its three chlorinated derivatives; 2', 3, 4, 4'-tetracholro-2-hydroxydiphenyl ether (II), 2', 4, 4', 5 -tetrachloro-2-hydroxydiphenyl ether (III) and 2', 3, 4, 4', 5-pentachloro-2-hydroxydiphenyl ether (IV), gave various polychlorinated dibenzo-p-dioxins (PCDDs) by pyrolysis. Some of PCDDs formed were identified by comparison of their¹H-NMR and mass data with those of the standards. The chemical structures of the others were inferred from their¹H-NMR and mass spectra. The results provided that by pyrolysis I gave 2, 8-dichlorodibenzo-p-dioxin (di-CDD) and 2, 7-di-CDD corresponding to the intramolecular dehydrochlorination and the Smiles rearrangement, respectively. However, II, III and IV gave further chlorinated dibenzo-p-dioxins other than PCDDs corresponding to the intramolecular dehydrochlorination, respectively. Especially, III produced 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (2, 3, 7, 8-tetra-CDD) which is the most toxic of PCDDs. This result suggests a new generating pathway of 2, 3, 7, 8-tetra-CDD other than those so far reported.

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2, 4, 4'-Tricholoro-2'-hydroxydiphenyl ether (Irgasan DP300) (I) and its three chlorinated derivatives; 2', 3, 4, 4'-tetracholoro-2-hydroxydiphenyl ether (II), 2', 4, 4', 5-tetrachloro-2-hydroxydiphenyl ether (III) and 2', 3, 4, 4', 5-pentachloro-2-hydroxydiphenyl ether (IV), gave various polychlorinated dibenzo-p-dioxins (PCDDs) by exposure to sunlight and UV irradiation of their aqueous solutions. The four compounds gave further chlorinated dibenzo-p-dioxins other than PCDDs corresponding to the intramolecular dehydrochlorination upon exposure to sunlight. The amounts of PCDDs formed from I were varied by coexisting compounds in the aqueous solution upon exposure to sunlight. These results suggest that the four compounds are precursors of PCDDs upon not only thermal reaction such as incineration but also photolytic reaction under the environmental conditions.

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The concentrations of polychlorinated dibenzo-p-dioxin (PCDDs) and polychlorinated dibenzofuran (PCDFs) in soil samples were measured for assessment of their contribution to environmental pollution. Subsequently, the relationship between their concentrations and the depth of soil sample, a comparison of the ratio of these concentrations with those in the air and their correlation with the ignition loss of soil samples were investigated. PCDDs and PCDFs in air dried soil samples were determined as follows. The soil samples were dried naturally in a room. The dried samples were extracted with methanol/benzene (1: 4, v/v) by Sohxlet extraction. After the addition of¹³C-PCDD and¹³C-PCDF as markers, the extracts were washed with potassium hydroxide solution, treated with sulfuric acid and cleaned by elution through a silver nitrate silica column, followed through a charcoal silica column. An aliquot of 1μl cleaned sample was analyzed by gas chromatography/high resolution mass spectrometry (GC/HRMS) . The summary of the results is shown below. PCDDs and PCDFs were detected in all soil samples. The concentrations ranged from 0.88 to 22 for total-PCDDs and 0.01 to 2.5 (ng/g, dry base) for total-PCDFs, respectively. In the PCDDs congeners, the highest level was found for the octachlorinated dibenzo-p-dioxin (71%) . The concentrations of PCDFs were less than those of PCDDs. The ratio of the concentration of each congener to total-PCDFs was in the range of 13-35%. The concentration of each congener of PCDDs and PCDFs in air decreased gradually with increase of number of chlorine substitution in both compounds. The concentrations of PCDDs and PCDFs were highest in surficial soil samples and decreased with the depth of soil. There was a relationship between concentrations of PCDDs and PCDFs, and the ignition loss of soil samples.

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A determination method of acephate in water samples was developed. Acephate was extracted twice with 50 mL portions of ethyl acetate from water samples added ammonium sulfate (80g/100 mL water sample) . The ethyl acetate layer was dehydrated with anhydrous sodium sulfate, and condensed to 1 mL using Kuderna-Danish apparatus. The condensed solution was dried up under a stream of nitrogen. The resulting residue was dissolved with 1 mL acetone for gas chromatography (GC) analyses. Acephate was analyzed by GC with FPD and FTD.
When acephate was added into distilled water (acephate concentration: 0.5-50μg/L), the recovery of acephate was 91.2% (reproducibility: 1.0%) . In the case of river water samples, the same recovery (92.3%) was obtained. In this method, the detection limit was 0.5μg/L.

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Leachates from 2 waste disposal sites were sampled in Japan. Volatile organic components were analyzed by gas chromatography/mass spectrometry and mutagenicity and acute toxicity of these leachates were examined. One of 2 samples showed mutagenicity and acute toxicity. Also, the leachate contained many kinds of organic compounds, some of which were 1, 4-dioxane, alcohols, phenols, aromatic amines, nitrogen-containing compounds, sulfur-containing compounds, and plastic additives.

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A reproducible method, based on the chemical oxidation and cholinesterase (ChE) inhibition assay, is described for monitoring trace of organophosphorus pesticides in aqueous samples. Chlorine was tested as oxidizing reagent for conversion of various thiophosphorus pesticides (P=S compounds) into thier P=O analogs having higher ChE inhibiting activity. After treatment with chlorine (10mg/L) of buffered pesticide solutions (pH 6.0) at 20°C for 15 min, ChE inhibiting activities and detection limits for each pesticide solution were determined. Greater ChE inhibiting activities, leading to the lower detection limits (ppb levels), were observed for chlorine-treated solutions fortified daizinon, EPN, parathion and fenitrothion and etc. This combination of oxidative derivatization and ChE inhibition assay was applied to the detection and determination of parathion, diazinon, and fenitrothion in natural water, soil, and vegetable samples at 1-300 ppb fortification levels.

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Toxaphene like compounds, of pinenes origin, from chlorination process were fractionated and used as a reference mixture to survey fishes inhabiting nearby pulp mill effluents. Several congeners, constituent of the fraction, tentatively designated as chlorinated pinenes (CPIs), were detected in fish tissue. For the sake of comparison, Baltic cod liver oil (The Baltic area is known to have toxaphene pollution record) was subjected to the same analyses. Interestingly, some songeners similar to those in CPIs mixture was found in the cod liver oil. Penta and hexachloro congeners found in CPIs mixture and other samples were present in toxaphene. Some congeners are likely to be accumulated in fish with the concentration ratio of fish to effluent as much as 10²to 10³. Thus it is probable that pulp mill effluents also contribute to the environmental pollution of toxaphene like compounds. Although total concentration in fish reported here (about 80 ng/g wet weight) was low to cause any health risk, further studies are needed to make clear the state of toxaphene like compounds pollution. Analytical approach demonstrated here is new and useful to determine hiherto unidentified pollutants regardless of the yet unavailable pure standards.

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Round robin tests were carried out to investigate the precision of pesticides in water. Two samples of waters with added diazinon, fenitrothion, chlorothalonil and chloroneb were analyzed by 15 different laboratories. The results showed that intralaboratory precision was better than interlaboratory precision by analysis of variance. Some laboratories produced more or less correct results attributed to systmatic erros.

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Each of local self-governing bodies has accumulated data of air pollutants. We have tried to make the concentration contours for the pollutants in Niigata city and Kubiki village using the data.
In this paper, we report the contours of chloride ion, sulfate ion, sulfur oxides and nitrogen oxides as air pollutants in Toyosaka city. To express the contours, the equation of smoke diffusion was utilized. The concentrations of nitrogen oxides and sulfur oxides were almost constant all the year round, while those of cloride and sulfate ions decreased in summer season. Probably, the difference depend on the location of the city, since the city is located near Niigata city and Niigata East Harbor (Industrial area) .
The specimens of low carbon steel were spread out in the city and the contours of corrosion rates were also drawn. The expected values of corrosion rates were calculated by a multiple regression analysis with chloride and sulfate ions. The values agreed well with the observed values in winter season.

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Method for simultaneous determination of asulam, oxin-copper, thiuram, simazine (CAT), mecoprop, napropamide, iprodione, bensulide (SAP) and pencycuron in water was investigated by high performance liquid chromatograpy (HPLC) . Pesticides in waters were absorbed on polystyrene gel mini cartrige. And then the pesticides on cartrige were eluted with acetonitrile and determined by high performance liquid chromatograph equipped with a column of RS pak DE-613 or NOVAPAK C18. The recoveries of these pesticides in distilled water were more than 80% except asulam and oxin-copper. And those in river water were more than 89% except oxin-copper. But those in tap water were less than 36% except mecoprop, iprodione and pencycuron. These low recoveries were caused by residual chlorine in tap water.

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The water samples were taken from 64 sampling stations settled along the Abukuma River and its tributaries, and analyzed to estimate the contamination level by eight volatile chlorinated compounds for three years (1989-1991) .
Trichloroethylene was mainly detected in the upper part of Koriyama in 1989. The maximum level was 2.7μg/l.
Tetrachloroethylene was detected only at several sampling stations, and its maximum concentration was 4.5μg/l.
Large amounts of chloroform were found at many stations (max: 20.5μg/l) . They would be a main volatile compound produced by chlorination of organic substances.
1, 1, 1-Trichloroethane and carbon tetrachloride were also found at many stations, but their levels were very low as compared with chloroform.
Dichlorobromomethane was detected only at one station. Chlorodibromomethane and chloropicrin were not detected at any stations through the examination period of three years.

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Dioxin analysis requires high sensitivity, high selectivity and specificity. Currently, the analytical method of choice is high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) using the SIM method after extensive clean-up.
In this paper, relative efficiencies and performances of both of various sample clean-up methods and HRGC/HRMS method were investigated and evaluated in detail. Some of the noteworthy problems were pointed out and discussed, and the most suitable combination of the procedures for Dioxin analysis were suggested.

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California's Proposition 65 law and implementing regulations have been in effect for over five years and represent dramatic and fundamental changes in public health and environmental regulation. The law, termed the Safe Drinking Water and Toxic Enforcement Act of 1986, is primarily aimed at keeping the state's drinking water free from hazardous chemicals. However, it also targets a range of consumer products (food, medicines, cosmetics, and household goods) by requiring public warnings if they contain amounts of carcinogens orreproductive toxicants exceeding“no significant risk levels.”Any citizen may sue a business thatviolates this law and retain a portion of the monetary penalties imposed by the law. Currently there are over 500 chemicals and mixtures on the regulated list, and many law suits have been filedand settled on a number of important chemicals. Chloroform, lead, ethylene oxide, perchloroethylene, methylene chloride, trichloroethylene, and asbestos have been the most significant cases. Public warnings are also now being given for alcoholic beverages and aspirin, and warning notices are posted at all gasoline-dispensing stations throughout the state.
A forthcoming article will present more information on the law's background, implementation, impact on industry, and future implications by Dr. Takayuki Shibamoto, Chaiman of the Department of Environmental Toxicology at University of California, Davis.

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