Recent studies on pulmonary clearance and toxicity of heavy metals (Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Cd, Hg and Pb) and Al (light metal) are reviewed together with comparative pulmonary toxicity among these metals. Metabolism and effects of Cd, Cr and Ni deposited in the lung have been relatively well investigated because these three elements are considered to have carcinogenic potency, but toxicological studies seem to be insufficient for the other elements. Solubility of metal compounds in the bronchoalveolar milieu depends on physical and chemical form (salts, oxide, sulfide, etc.) and may play a major role in pulmonary clearance rate, acute toxicity and carcinogenecity. Therefore, attention should be paid to the species of elements present in the environmental and work place atmosphere. The current Threshold Limit Values (TLV) for gallium, aluminium and zinc oxides might not be adequate and should be thoroughly reexamined. Toxicological priorities relevant to the work environment are discussed.

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Paraquat (1, 1'-dimethyl-4, 4'-bipyridylium), a widely used and effective herbicide, can cause a severe lung injury in both humans and experimental animals. The injury is characterized by initial damage to the alveolar epithelium and capillary endothelium with the development of hemorrhagic pulmonary edema, followed by development of intra-alveolar and interstitial fibrosis. Although the lung is thought to be a primary target organ for paraquat toxicity, the mechanism of action of this herbicide remains to be uncertain. A possible mechanism of selective toxicity to the lung is the accumulation of paraquat in the lung. Data from experimental animals in vivo and in vitro indicate the accumulation of paraquat in the lung by an energy-dependent transport system. However, paraquat does not appear to be selectively concentrated by the lung in human paraquat poisoning. A widely accepted theory regards lipid peroxidation and NADPH depletion as the basic mechanism of paraquat toxicity. According to this theory, paraquat can be reduced by microsomal enzymes and undergoes a cyclic reduction and reoxidation, giving rise to a reactive oxygen radical. This continuous generation of oxygen radicals within the cells of the lung then in turn destroy this tissue through various mechanisms of oxidative damage such as lipid peroxidation and NADPH depletion. However, there are data in the literatures that contradict the active oxygen species theory of paraquat toxicity. Most of these findings show a lack of extensive oxidative damage to the lung. Extent of lipid peroxidation and NADPH depletion is not always correlated with that of lung tissue damage. Moreover, the mechanism of paraquat toxicity leading to the development of lung fibrosis have not been fully elucidated. Recent studies suggest that inflammatory cells such as polymorphonuclear leukocytes and alveolar macrophage, and chemical mediators released by these cells may play an important role in lung fibrosis caused by paraquat. To sum up, the mechanism of selective lung toxicity in paraquat poisoning is not clearly explained by the theory mentioned above. Study on the secondary pulmonary response following cell injury directly caused by paraquat may become a clue to elucidate this mechanism.

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In order to establish the method of bio-assay for the safety of drinking water, promotion activity and cell toxicity of water micropollutants were studied by use of the morphological change and cell viability of HL-60 cells which were cultured with the substances recovered from raw and chlorinated waters by the adsorption with XAD-2 and activated carbon, and the results were compared with those of Ames Salmonella mutagenicity test. Among 51 fractions obtained from raw and chlorinated waters, no fraction induced differentiation of HL-60 cells to macrophage which is typically observed by the action of 12-O-tetradecanoyl-phorbol-13-acetate (TPA), suggesting no occurrence of promotor in water tested. Some fractions decreased the cell viability of HL-60, indicating the occurrence of cell toxic substances in water. Ames Salmonella mutagenicity test indicated the occurrence of mutagens in some fractions, but no correlation was observed between the results of HL-60 cell viability and mutagenic activity. These facts suggest the importance of bio-assay with culture cell systems.

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The polycyclic aromatic hydrocarbons (PAHs) extracted by blue-cotton (BC) from river waters were analyzed by reversed-phase high-performance liquid chromatography (HPLC) with a spectro-fluorometric detector. Kanzaki River, an affluent of Yodo River in Osaka Prefecture, showed more serious water pollution in terms of BOD, DO, SS, and the number of E. coli, compared with Kako River in Hyogo Prefecture. Mutagenic activities of blue-cotton adsorbed materials from Kanzaki River were markedly higher than those from Kako River in the Ames test using Salmonella typhimurium TA98 and TA100. The extracts showed potent mutagenic activity to TA98 with S9mix. Ten PAH standards were well separated by the reversed-phase HPLC. Six PAHs were found in water from Kako River, all of which increased in proportion to the weight of BC immersed (0.25-2 g). In Kanzaki River, eight PAHs were detected. The total amount of PAHs in Kako River and Kanzaki River were estimated to be 30 and 101 ng/g BC, respectively. These results showed that both PAHs and mutagens, which were adsorbed to blue-cotton, increased with aggravation of water pollution in river waters. However, the mutagenic activity of the extracts could not be explained by the amount of PAHs detected, which might be attributable to polar derivatives of PAHs.

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To demonstrate the availability of the water extraction-TBA (2-thiobarbituric acid) method, which had been improved by us for a test of fats deterioration, the reaction products in this method were analyzed by spectrophotometry and high performance liquid chromatography (HPLC). A red pigment with absorption maximum at 532 nm was formed by a reaction of malondialdehyde with TBA, which eluted at 5.6 min on the HPLC chromatogram. The reaction mixture of TBA and water extract from oxidized linoleic acid showed three absorption maxima at 450 nm, 495 nm and 532 nm. The HPLC could separate three reaction products into yellow (P-I), orange (P-II) and red pigments (P-III) with retention times at 2.3 min, 3.4 min and 5.6 min, respectively. The P-III was identical with the malondialdehyde-TBA adduct. P-I, P-II and P-III were also detected in the TBA test of water extracts from other rancidified fats (shark oil and soybean oil), as well as from oxidized linoleic acid. The TBA values obtained by the water extraction-TBA method with spectrophotometric detection corresponded well to those determined by the HPLC method in which the malondialdehyde-TBA adduct (P-III) was analyzed. Present results further demonstrated the availability of water extraction-TBA method as a convenient test for the determination of fats deterioration.

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The interference effect of PO₄^3- on the recovery of Cd, Cu, Mn and Pb in water during determination by coprecipitation with Zr(OH)₄ followed by flame atomic absorption spectrometry (FAAS) was investigated. Free PO₄^3- in water, from 0.125 to 1.5 mg/ml, exhibited weak interference on the recovery of these metals, giving rise to errors of a few to several percent in the direct FAAS analysis. In the coprecipitation method, Zr⁴⁺ showed an unfavorable property to FAAS, forming a precipitate of phosphate which was insoluble to both water and (1+1) HCl. The above problems were solved by precipitating PO₄^3- with Zr⁴⁺ followed by washing the precipitate with (1+1) HCl, solubilizing the coprecipitated metals quantitatively, and removing PO₄^3- by centrifugation as acid-insoluble Zr⁴⁺ salt.

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This paper presents determination of x-carrageenan in foods by sandwich enzymeimmunoassay. x-Carrageenan was determined after removal of fat and dyes from various foods with dioxane. Amount of x-carrageenan in jelly was between 0.24 and 0.76% and the recovery was between 89 and 101% when 1.0% of carrageenan was added to jelly. For pudding, ice cream, whip cream and jam, the recovery was between 89 and 99% when 0.2-1.0% was added to each food.

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0.1% NH₂OH (2.5 ml), 5 N HCl (2.5 ml) and 1% m-aminophenol solution (1 ml) were added to unsaturated fatty acid methyl enters (10 mg), and the mixture was heated in a boiling water bath at 100°C for 20 min. The reaction mixtures were measured for their fluorescence intensity at Ex. 356 nm and Em. 505 nm, and the amounts of acrolein formed were determined from its calibration curve. Methyl linolenate oxidized for 20 h at 80°C, 2258.2μg/g of acrolein were formed, whereas 208.1μg/g of malondialdehyde were determined by the thiobarbituric acid method. Thus the determination of acrolein in oxidized lipid may have some fundamental significance for the evaluation of lipid oxidation. It was of interest that acrolein is formed not only from glycerin and triglyceride but also from unsaturated fatty acids by their autoxidation.

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