A research on a treatment system of human excreta provided for the use in mountainous areas was carried out. The system was composed of two treatment processes, an anaerobic digestion and a seepage spray process. Vertical distributions of chemical components were observed in the anaerobic digestion tank, because the top of the tank was covered with water permeable phase and rain water was penetrated into the tank. Comparing the amount of inflow into and of evapotranspiration from the system, about 70% of the inflow was overflowed from the seepage spray tank, under the assumption that the whole rain water fallen on the system was permeated into it.

As high molecular weight amine were able to extract trace cadmium, copper and lead Into an organic phase at the potassium iodide-sulfuric acid, simultaneously, conditions for determination directly organic phase with atomic absorption spectrophotometry were investigated. By setting potassium iodide concentration and sulfuric acid concentration at 0.2M and 3.6 N, respectively, cadmium, copper and lead were extracted with 5v/v% Amberlite LA-2-n-Buthyl acetate solution simultaneously. Under the conditions above described, the extraction rate of cadmium, copper were 100% and its of lead was 98%. The coefficient of variation were proved to be 0.71%, 1.47%, 1. 30%; which were obtained by the 20 repeats of determination with 1 micro g/ml cadmium, copper solution and 5 micro g/ml lead solution With regard to the effect of coexisting ions, alkaline metals, alkaline earths metals, Fe(II), Zn(II), Al(II), Mn(II), Cr(IV), Si(IV), Ni(II), As(III) etc. did not interfere. The method was applied to the determination of cadmium, copper and lead in hair with satisfactory results.

An outbreak of food-poisoning caused by a urea-hydrolyzing strain of Vibrio parahaemolytictis is presented. In the outbreak, urea-hydrolyzing V. parahaemolyticus was the only suspected etiological agent isolated from patients. In other respects, the strains conformed to the general characteristics of V. parahaemolyticus. The isolates were positive to the Kanagawa phenomenon and thermal direct hemolysin test. Urea-hydrolyzing strains of V, parahaemolyticus have rarely been reported and have not been described previously as a cause of food-poisoning in Japan. Eleven urea-hydrolyzing strains were found among the strains of V. parahaemolyticus isolated in our laboratory previously from various materials. Six of them were isolated from travellers to South-East Asia. A total of 16 strains of urea-hydrolyzing V.pamkaemolyticus was typed into 7 serovars (e. g. O4: K12, O6: K18, O1 : KUT. O3: K15 etc.).

A survey of the incidence of Salmonella in samples collected from three treatment plants of sewage, food-poisoning, sporadic case with acute enteritis and healthy carrier in a local city, was performed from Aprile 1974 to December 1978. Salmonella were very frequently found in Influent sewage. The range of sewage source serovars found was wide and most aerovara were related with human source. A total of 954 strains and 62 serovars of Salmonella were found in sewage and human source. S. typhimurium, S.tennessee, S.thompson, S.infantis, S. senftenberg and S.oranienberg were the most frequent aerovars. It might be presumed that the environmental contamination of the area by the organisms is increasing gradually, since new aerovars of Salmonella, for example S.havana, S.agona, S.london, S. mission and S.cerro etc., which were never found in Nagano prefecture before, were isolated in the area. Effect of addition of the Aluminum sulfate and Polyacrylamide for Salmonella isolation from sewage, were studied. By use of the floe method. Salmonella were more frequently isolated from influent sewage.