To examine the distribution and status of Cu, Cr, Pb, Zn, Cd, and Ni in the mud of Tsurumi River, surface mud samples were collected at 8 stations from the mouth to up the river. Total heavy metals of mud in the upper and middle part of the river showed values near the mean of heavy metals in Japanese rivers of the first category. Ethylenediaminetetraacetic acid (EDTA)-soluble Cu represented 30% of the total Cu, while Cd, Pb, and Zn 10 to 20% and Cr, Ni about 5%. Acid-soluble heavy metals were 10% higher than EDTA-soluble heavy metals. In the mouth of the river, near the Tsurumi industrial area, the total heavy metals were 2 to 6 times more than that in the upper and middle of the river. EDTA-soluble Cu and Cd showed about 60% of the total Cu and Cd, Zn and Pb about 70% and Cr and Ni 10 to 20%. Acid-soluble heavy metals were 10 to 20% more than that of EDTA-soluble metals. Therefore 1/2 to 2/3 of total heavy metals were extracted with 0.5 N HCl. These data indicated that a large portion of heavy metals in the mouth of the river came from industrial wastes and that such heavy metals can be extracted with 0.5 N HCl or EDTA.

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Heavy metals in the bottom mud at the mouth of 91 rivers in Japan were analyzed and the data were published in a paper. In order to compare with these data, the distribution of heavy metals in the bottom mud up the river was studied in the present work. Samples of the mud were collected from the upper stream near the mountain, not polluted with waste water. It was concluded from these data that the concentration of the heavy metals among 193 mud samples up the river dispersed in a narrow limited range, compared with that of the river-mouth, i. e., the range of Ni and Cr concentration was 1-25ppm, that of Cu and Pb, 4-50ppm, Zn 10-200ppm, Cd 0.08-2.00 ppm, and Hg 0.0-1.0 ppm. The value of the mean of heavy metal concentration up the river decreased to 1/2 or 1/3 of those at the mouth of the river.

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Bottom mud was collected from the upper and lower streams of 91 rivers in Japan to determine the distribution of Al, Fe, and Mn extracted HNO₃-H₂O₂ and 0.5 N HCl. The concentrations of Al, Fe, and Mn extracted by HNO₃-H₂O₂ ranged from 2, 900 to 67, 000 mg·kg_-1, from 1, 500 to 57, 300 mg·kg_-1, and from 23 to 861 mg·kg_-1 of dry mud, respectively. About 95% of all samples contained 0.5 N HCl soluble Al of less than 5, 000 mg·kg_-1 and their concentrations corresponded to about 10% of HNO₃-H₂O₂ soluble Al. No difference between the upper and lower streams in the distribution of 0.5 N HCl soluble Al could be observed. About 90% of the samples from the upper stream and 35% of the samples from the lower stream contained 0.5 N HCl soluble Fe of less than 5, 000 mg·kg_-1. A soluble Fe in 0.5 N HCl increased in the lower stream. The concentration of 0.5 N HCl soluble Mn was less than 300 mg·kg_-1 in almost all rivers, and the average concentrations decreased slightly in the lower stream. The variation coefficients of these three metals extracted by HNO₃-H₂O₂ and 0.5 N HCl were smaller than those of trace metals.

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In order to clarify the distribution pattern of heavy metals contained in the bottom mud of urban rivers, the metals were fractionated by extraction with 2N CH₃COONH₄ and 0.5N HCl. The total metal content was determined after the decomposition with HNO₃-H₂O₂. A part of the Cu, Zn, and Cd in the bottom mud of urban rivers was extracted with 2N CH₃COONH₄, but the Pb, Ni and Cr were unextractable. This result indicated that the forms of metals in bottom mud differed from one another. The metal content increased in the lower reaches of the urban river, and the amount of the increased metals was approximately equal to those of the metals extracted with 0.5N HCl. The increase of metals downstream was also correlated to the grain size and the organic matter content of bottom mud. These results suggested that a significant part of the metals in the bottom mud of urban rivers were weakly bound to fine grain size sand and organic matter.

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In order to separate the different forms of heavy metals contained in bottom mud of urban and mining rivers, fractionation of metals by chemical extractants was carried out. Heavy metals were fractionated by successive extraction with 2N-CH₃COONH₄, 0.1M-EDTA and 0.5N-HC1, and by decomposition with HNO₃-H₂O₂. The lattice-held metals, which were separated by HNO₃-H₂O₂ decomposition, were 70-80% of the total in the bottom mud receiving waste water from mining industry, suggesting that the most of these metals were composed of ore minerals. On the other hand, the fraction of HNO₃-H₂O₂ was only 20-30% in urban rivers receiving industrial or municipal waste water. The major fractions of the heavy metals were separated with 2N-CH₃COONH₄ or 0.1M-EDTA. It was suggested that large parts of Cd, Zn, and Cu in the mud of urban rivers bind weakly with clay or organic matter and Pb binds more strongly with organic matter.

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Tish investigation was conducted in order to examine whether the content of heavy metals, i. e., mercury, cadmium, leed, copper, zine, manganese, nickel, cobalt, chromium, and arsenic in short-neck clams Tapes japonica, was correlated with that in the nearby mud.
Pair samples, clam and mud, were simultaneously collected from fifteen stations of the waters of the Inland Sea in Yamaguchi Prefecture where industrial pollution was not expected. After wet digestion, the heavy metals in the edible portion of the clam samples were determined by colorimetric and atomic absorption spectrometric methods. The mud samples were treated with acid extraction (0.1 NHCI and 0.001 NHCI) in addition to wet digestion, and the metals were determnined by the same methods as used for the clam samples.
The results obtained are as follows:
1. In the mud samples, the extraction rate of heavy meatls by acid solutions varied widely with the kind of metals and the location of sampling. The variation was highest for cadmium and lowest for mercury.
2. The levels of heavy metals in the short-neck clams and the mud were within the standards of food hygiene and environmental sanitatio, respectively.
3. There was no relationship between the heavy metal contents in short-neck clams and those in the mud where the clam inhabited.

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Contents of heavy metals, ignition loss and clay were measured in sediment samples of the lower reach of the Nagara River and the data were subjected to multiple regression analysis. Heavy metal contents in sediments were correlated significantly with ignition loss and clay contents. Multiple regression coefficients were more than 0.92 among these three factors. Heavy metal concentration in sediments could be predicted with probability of over 85% by estimating ignition loss and clay using the multiple regression equations. The amounts of heavy metal accumulation on unit mass of ignition loss and clay were able to be separately calculated from the regression equations. Heavy metal accumulation on sediments was dependent more highly on ignition loss than clay. Constants in regression equations were good approximations to analytical results of heavy metals in sediments of unpolluted area in the river, therefore, they could be regarded as background values of heavy metals in sediments of the river.

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In river sediments, heavy metals are adsorbed to the components, such as, clay and humic substances. The adsorbing abilities of clay and humic substance are compared. The adsorbing ability of humic acid is stronger than that of clay for all heavy metals at pH 4. The ability of humic acid reduced under the co-existence with clay.

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Concentrations of contaminated heavy metals (Cu, Pb, Zn, Cd, Cr, Mn, Ni, Co) in the stream sediments at 21 points of the Akashi River system (Akashi River and Ikawa River) are determined for the assessment of the environmental pollution. These stream sediments were sieved into the three fractions: <63 μm, 63∼125 μm, and 125∼250 μm sized grains. Then the analyses of the heavy metal concentrations were performed after the standard procedure for the environmental analyses. The finest portions of all the analyzed sites show the higher concentrations of the heavy metals than the other two divisions. The loss on ignition (LOI) at 600°C is positively correlated with the metal concentrations. Among the analyzed elements, the correlation for Cd is stronger than the correlations for the other elements. Correlation coefficients for all the analyzed elements are higher than those between LOI values at 1200°C and heavy metal concentrations.

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The benthic fauna of the Iseri River a polluted river in Kumamoto City, was investigated in connection with the water quality and accumulation. The benthic fauna was influenced significantly by the organic content in water and by the sulfide-producing accumulation. It may be concluded that the examinations of the benthic fauna which respond well to the changes of the environmental conditions will give useful informations on the stream pollution.

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Distribution of Cu, Cr, Pb, Zn, Cd, Ni, and Hg in mud of Japanese rivers of first category was investigated with 178 mud samples from the mouth of 91 rivers, collected from August to September, 1973. The mud from the rivers in San-in district on the Japan Sea coast showed the lowest amount of all the heavy metals. The samples obtained from the Tsurumi or the Yodo River, near the industrial area, showed a very high concentration of all the metals. From the calculated values of the mean and standard deviation of each metal, it was considered that the higher these two values were, the more the river was polluted. The mean value of fignition loss was 5.03%. On the basis of this value, all the river were grouped into two classes. The first group had below 5.03% of ignition loss and the other with higher value. The mean and standard deviation of heavy metals of the former group were smaller than those of latter. Marked difference in concentration of Cd and Hg was observed between the two groups, while no difference was observed in the concentration of Ni. These results indicate that the mean of each metal in the first group river may be considered as approximate value for Japanese river mud in natural state.

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マウスの感染防御試験において, いわゆるin vivo効果が優れているとされる第III世代のcephemsのAC-1370, cefoperazone (CPZ), cefbuperazone (CBPZ), ceftazidime (CAZ), ceftriaxone (CTRX) の食細胞機能 (遊走能, 貧食能, nitroblue tetrazolium (NBT) 還元能) に及ぼす影響についてcarbenicillin (CBPC) を含めて検討し, 以下の結論を得た.
1. 遊走能試験の中のchemotaxisisに及ぼす影響については, 各薬剤濃度が100μg/mlではAC-1370のみが, stimulation index (S.I.) 1.40で増強作用を示し, 他剤には増強作用は認められなかった. spontaneous migrationについてもAC-1370のS.I.は1.43で, 増強作用を示し, 他剤には増強作用は認められなかった.
2.各薬剤濃度が500μg/mlの条件下の貧食能試験で, AC-1370はS.I. 1.36で, 増強作用を示したが, 他剤には増強作用は認められなかった.
3.尿中で, 末梢血分離多核球の貧食能を検討した.また600mOsm/l以下の浸透圧ではA℃-1370の100μg/mlの添加にて貧食率が平均24%上昇した.
4.各薬剤濃度が267μg/mlの条件下のNBT還元能試験で, AC-1370のS.I.は1.62で最も強い増強作用を示し, CPZとCBPZのS.I.は共に1.31を示し, 他剤は1.30以下であった.
5.以上によってAC-1370には食細胞機能を全般に直接増強させる作用があるものと思われた.

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A study was carried out on the pathway and the trend of mercury pollution of bottom sediments of the Suimon River. It was difficult to establish the actual mercury pollution level of sediment only with a data of mercury content of sediment because measured values of mercury fluctuated intensely even in an identical sampling station. Then, the triangular coordinate chart method was applied to compare the pictures of mercury pollution among different sampling stations and the years of mercury measurement. It was useful for the selection of metals in a triangular coordinate chart to check previously the probability distribution of metal concentrations in sediments. The combination of mercury, cadmium and copper was appeared to be most excellent among fifteen combination of metals in triangular coordinate charts for the investigation of mercury pollution. The plots in the Hg-Cd-Cu triangular coordinate chart successfully account for the pathway of mercury pollution of sediments. And when comparing the results of yearly analysis of mercury in sediments in the triangular coordinate chart, there was found little fluctuation of mercury pollution among the years.

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Sediment samples were collected from 44 locations of a typical polluted urban river, the Sumida (Shingashi) River, which runs through the Tokyo area and pours into the Tokyo Bay, Japan. Fine particles under 76 μm diameter were sieved and analyzed for concentrations of Cr, Ni, Cu, Zn, Cd, Pb, organic carbon and nitrogen. The analytical results showed that most of the samples from upstream to downstream of the river were heavily polluted with those metals probably originated from waste waters of urban activities in the drainage area. The characteristics in the metal compositions and their distributions were examined by calculating the concentration correlation matrices and the correlations between elements. It was found that the heavy metal composition except Ni was nearly uniform among the majority of the samples from mid- to downstream of the river. The reference sediment samples from 22 and 6 locations near the river mouths of Tama-gawa and Ara-kawa, respectively, which run adjacent to the Sumida River, were analyzed in the same way. It appeared that there are some specific heavy metal compositions, probably reflecting the degree and quality of pllution to each river.

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　目的：交代勤務が看護職にとって避けられない勤務体制であることから，どのような勤務体制が看護職にとって身体的・精神的疲労が少ないのか，看護職はどのような勤務を望んでいるのか把握するために文献検討を行った． 　方法：データベースは医中誌を用い，キーワードを「看護師」「疲労」「勤務体制」とし，論文種類を原著論文として検索した．勤務体制と疲労の関連性について述べていないものに関しては除外し20文献を対象とし，それぞれの結果を勤務体制と身体的疲労，精神的疲労に分類し比較した． 　結果：身体的精神的疲労は，勤務時間の長さ，勤務時間中の休憩時間の長さ及び勤務間隔の長さに影響していた．二交代制勤務の方が三交代制勤務よりも疲労回復が早く，蓄積疲労も低くなっている．三交代制勤務に比べ，プライベートの時間の充実度が増し，通勤の負担などの軽減がみられた． 　結論：二交代制勤務は三交代制勤務より休息時間が長いことで疲労回復ができ看護職の疲労の軽減ができていた．勤務時間外の家事や子育てなどの疲労も関係してくるため，二交代・三交代制勤務以外にも様々な勤務形態について調べていく必要がある．

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Recently the amounts of various kinds of wastes have increased, as the industrial production has increased and the living standard has elevated in our country. Consequently, the environmental pollutions have advanced all over the country. In an investigation of the environmental pollution, aquatic sediments are found to be useful because hazardous substances are often adsorbed and concentrated in sediments. Perhaps heavy metals are most extensively studied in hazardous substances. In this review, the emphasis is placed the extraction techniques of heavy metals from sediments, the distribution of heavy metals in sediments, and the evaluation of pollution by heavy metals.

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