“Fifteenth International Symposium on Chlorinated Dioxins and Related Compounds” was held in Edmonton, Canada from August 21 to 25. It started with the discussion around US EPA's reassessment on dioxin which was released on September 13, last year. Four hundred and six papers were presented. “Human health risk assessment”, “bioremediation”, “atmospheric processes” and “toxaphene” were 4 sessions newly arranged.

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I Environmental Protection Technology in France by Olivier Herz (ADEME)
II French Environmental Research Development Policy by Jean-Claude Oppeneau (ADEME)
III Industrial Means Implemented in France for Municipal and Industrial Solid Waste Management by Olivier Herz (ADEME)

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Anthraquinone is an important dye intermediate and is known also as a digest-aid chemical in pulp manufacturing since 20 years ago.
Recent studies revealed, furthermore, that anthraquinone inhibited sulfate respiration of sulfate-reducing bacteria in the sludge of wastewater so that evolution of hydrogen sulfide was effectively diminished. Follow up fieldworks are under way.
Here are presented two field-test results, one obtained at a force main line of the Wastewater Treatment Plant for the City of Tampa, Florida, and another obtained at an underground reservoir or a pit of a building in the city of Tokyo.
The anthraquinone formulation is expected to make an excellent means of diminishing foul sulfurous odor and preventing sulfuric corrosion at public sewage systems, pulp and paper mills, fermentation and food-processing plants, dyehouses and oil fields.

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N-chloro-polyacrylamide (N-CI-PAM) improved the paper strengths to a great extent. However, the effects decreased very much when the N-chlorination was carried out for a long time, even though the N-chloro group still remained. To elucidate the origin, the change of molecular weight (MW) of polyacrylamide during N-chlorination was investigated by means of size exclusion chromatography. Although N-chlorination of PAM occurs easily, it does not progress completely and small amounts of NaOCl always remains freely. MW of polyacrylamide decreased with increasing time of N-chlorination due to the cleavage of polymer chains by remaining NaOCl. Since the degree of N-chlorination passes through a maximum during the N-chlorination of PAM, two kinds of N-Cl-PAM with the same degree of N-chlorination but different MWs could be prepared by changing reaction times. The improvement of paper strength by N-Cl-PAM obtained for long reaction time was appreciably lower. The polymer molecules with lower MW are easier to penetrate into small pores of fibers so that the numbers of their bridging on surface of fiber decrease. Thus the improvement of paper strength by N-Cl-PAM also decreased with decreasing MW.

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The observation of lignin distribution in the cross section of Acacia chips and the digester rejects in kraft pulping was carried out by using EPMA (Electron Probe Microanalyzer) with the newly developed procedure of Osmium-tagging to lignin, presented in the previous report. The distribution pattern of lignin can be detected clearly by the distribution and concentration of the Osmium tagged to lignin. STEM-EDS (Scanning Transmission Electron Microscope-Energy dispersive X-ray Spectrometer) technique was also applied to observe more precisely the distribution of the Os-tagged lignin in wood components. The observed results are summarised as follows ;
(1) More vessels, which were thickly surrounded by vasicentric parenchyma cells, were observed in the cross section of the KP rejects than in that of the chips.
(2) It was found that the lignin concentration is high in these vasicentric parenchyma cells for the KP rejects and on the other hand it is high in ray parenchyma cells for the normal chips. High Osmium concentration in parenchyma cells may be thought to depends not only lignin but on resinous substances which can not be extracted with alcohol benzene.
(3) STEM-EDS analysis revealed that in the KP rejects fiber cell walls are considerably deformed and delignified but firmly combined with lignin rich middle lamella.
(4) The distribution of the lignin in the cross section of the KP reject resembled that of the chips near the knots. Accordingly, it is considered that the difficulty of digesting of chips much depend on the distribution of lignin in the chips.

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(1) The antibiotic activity of carboxylic acid changes remarkably with the species of micro-organisms. Twenty six carboxylic acids (mainly phenol carboxylic acid) were tested toward four kinds of micro-organisms, namely Escherichia coli, Bacillus subtilis, Saccharomyces cerevisiae and Aspergillus niger. It is difficult to systemize the activity by the relative position of phenolic hydroxyl and carboxyl groups on aromatic nucleus.
There have been identified the alkali degradation products of softwood lignin, namely phydroxybenzoic acid, vanillic acid, protocatechuic acid, syringic acid etc. Comparing the relation between the chemical structure of the above phenol carboxylic acids and the antibiotic activity toward micro-organism, it is summarized that the activity of carboxylic acid ester is higher than that of free carboxylic acid, and methoxyl group brings a considerable reduction in the activity.
(2) Lignosulfonate and thiolignin do not give the antibiotic activity. In order to give the activity to industrial lignin, the introduction of phenol carboxylic acid type structure into lignin was tried by the use of alkali fusion method. Within the limit of research, so far, the ethanol soluble fraction from alkali fused lignin shows comparatively high activity, although the activity toward Aspergillus niger was not observed. It should be emphasized here, however, that there is no proof of the formation of phenol carboxylic acid type structure in alkali fused lignin.

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