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Volume 47, Issue 1
Displaying 1-9 of 9 articles from this issue
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Hideo NISHIDA, Masaya MIYAI1986 Volume 47 Issue 1 Pages 1-9
Published: January 30, 1986
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThere are various means of determining the heavy metal critical pollution point of river sediments. This study presents a method for determining a critical point of pollution by using the quantities :
T=_??__??_σjj' log10(a+byj) log10(a+byj')
where, the suffixes j and j' correspond to the j-th and j'-th metals, respectively, the n×n matrix [σjj'] is the inverse of the population variance-covariance matrix of n heavy metals in upstream rivers, and a and b are the arbitrary constants. yj denotes the average of m independent measurements of the concentration of the j-th metal of the typical downstream river. Values of log10 (a+byj) are regarded as being distributed as N (μ, ∑), and hence T follows a noncentral chi-square distribution. Using PEARSON'S approximation for a central chi-square distribution, a critical pollution point is obtained. Application to first class rivers in Japan showed a qualitative comparison of the intensity of pollution.View full abstractDownload PDF (1156K) -
Hideo NISHIDA, Sadao IKEDA, Masaya MIYAI1986 Volume 47 Issue 1 Pages 11-15
Published: January 30, 1986
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThe authors (1981) proposed a dissimilarity measure for analyzing concentration-ratio data. Statistical distribution of this measure is derived when the original data are drawn from a p-dimensional lognormal distribution. This allows one to determine statistically whether two samples come from the same population. The result is applied to the data, according to KIBA and MATSUMOTO (1978), on bottom sediments of tributaries of the Jintsu River in Japan.View full abstractDownload PDF (606K) -
Norio OGURA, Akira ISHINO, Kiyoshi NAGAI, Isao TANGE1986 Volume 47 Issue 1 Pages 17-26
Published: January 30, 1986
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSBehaviour of nitrogen compounds in surface runoff water was investigated at small watershed (Hs-1) of Tama Hill during 1976-1982.
Budgets of nitrogen compounds were estimated by nitrogen content in precipitation (rain in the open plot, throughfall and stemflow) and surface runoff water during May-September 1982. Runoff coefficient of water (ratio of amount of surface runoff water to that of precipitation) amounted to 63%. Input of nitrogen by throughfall and stemflow was 1.6-2.4 times larger than that by rainfall in the open plot.
Runoff coefficients of NH4-N and NO3-N were 3% and 480%, respectively. Assuming that NH4-N in rain water is oxidized to NO3-N in soil and eluted to surface runoff water, runoff percentage of NO3-N becomes 270%. Average runoff coefficient of nitrogen during five years amounted to 180%. At the experimental watershed of the Tama Hill, the nitrogen output by surface runoff water was larger than the input by precipitation, suggesting that the watershed is not in the state of stable or climax forest ecosystem.View full abstractDownload PDF (1411K) -
-Case Study at Dredged Area in Southern Basin of Lake Biwa-Michio KUMAGAI, Hiroto MAEDA, Yukio OONISHI1986 Volume 47 Issue 1 Pages 27-35
Published: January 30, 1986
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSIt is well known that the deficiency of dissolved oxygen or the formation of an anoxic layer is observed in the hypolimnion of a stratified eutrophic lake in a heating period. The authors intended to clarify the mechanism of the formation of this anoxic layer by means of in situ data and a simple numerical model, focussing on vertical diffusivity, the precipitation rate of chemical component estimated by COD and the second order rate constant between chemical component, i. e. COD, and dissolved oxygen, which are the most important parameters for predicting the change of dissolved oxygen concentration in the hypolimnion.
The results showed that the consumption of dissolved oxygen in the bottom water is strongly dependent on the precipitation rate of organic matter and rate constant, where the dissolved oxygen is transported from surface to bottom by vertical diffusion. Hence, the faster the precipitation rate is, the more the anoxic layer tends to occur in the hypolimnion. And if the precipitation rate is fixed, the anoxic layer is most liable to occur at the particular rate constant.View full abstractDownload PDF (2011K) -
-Seawater Intrusion into Groundwater in Gogo Island-Tadao KAKINUMA, Kunimitsu INOUCHI, Atsuhito INOUE1986 Volume 47 Issue 1 Pages 37-51
Published: January 30, 1986
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThis report deals with the problem of the groundwater pollution caused by seawater intrusion into phreatic and confined aquifers of Gogo Island, Ehime Prefecture. Groundwater levels and chloride ion concentrations in shallow wells were measured in five districts on this island from August 1983 to December 1984. High chloride ion concentrations far greater than 200 ppm, the standard value of city water, were found in coastal regions of the Yura district, whereas the level were very low in other districts. In the Yura district, groundwater levels and chloride ion concentrations in deep wells as well as tide levels were measured. Chloride ion concentration profiles show the rapid increase of the concentration in the neighborhood of the well bottom. A modified KISHI and INOUCHI' s model to analize the variation in the groundwater level and fresh-salt water interface in response to the tide was applicable to a confined aquifer with an exponentially varying thickness. The thickness of the confined aquifer estimated from this analysis was in fairly good agreement with the one obtained by the boring examination.View full abstractDownload PDF (2203K) -
I. Sedimentary Processes Derived from the Grain Size Distribution of Surficial Sediments.Kazuhisa CHIKITA1986 Volume 47 Issue 1 Pages 53-61
Published: January 30, 1986
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSIn Lake Okotanpe, Hokkaido, surficial sediments were picked up at 59 points from the lake bottom, lake shore, and river bed and -bank. All the samples were analyzed for grain size and ignition loss. From the analytical results, the following conclusions can be drawn :
1. The lake bottom sediments, as a whole, consist of more than 80% silt and clay in weight. Excessive sedimentation in the lake could take place during the torrential floods of influent rivers, carrying a large washload of much silt and clay.
2. The lake sedimentary processes are represented by transportation and deposition of the fine suspended grains due to river induced turbidity currents and sediment dispersion.
3. The turbidity currents have a hydrodynamic feature of being controlled considerably by the topography of the lake basin. Therefore, the 'threshold' and the 'constricted' wall characteristic of the basin shape of Lake Okotanpe, can induce the convergence and subsequent lateral spreading of turbidity currents. Consequently, they cause sediments to have a more fine-textured, poorly sorted and almost log-normal grain size distribution.
4. The flowing condition of sediment dispersion is controlled by convective currents induced in the inflow-outflow system of the lake. Its sedimentary region is limited to the southmost area of the lake.
The flowing processes of suspension, controlled by turbidity currents and sediment dispersion, are consistent with the flowing conditions of river induced currents observed in October 1983.
Ignition loss for the lake bottom sediments, as a whole, ranges from 5 to 20%. The organisms almost all originate in the terrestrial plants. In the northeast recess, however, the ignition loss reaches the maximum of 30%, where an artificial effect is added.View full abstractDownload PDF (1542K) -
Akifumi OHTAKA, Hiroshi MORINO1986 Volume 47 Issue 1 Pages 63-75
Published: January 30, 1986
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSA quantitative investigation of the epiphytic animals living on a freshwater submerged plant, Potamogeton malaianus, was carried out in Lake Kita-ura from December 1980 to December 1981. The total individual number of epiphytic animals except for protozoans, rotifers and aeolosomatid annelids fluctuated between 0.5 (cm-2 leaf area) in September and 22.1 (cm-2 leaf area) in January, showing a high peak in the winter period and a lower one in the summer. This fluctuation was correlated with the abundance of epiphytic matter. Among the epiphytic animals examined, both oligochaetes and nematodes predominated in most seasons, while cladocerans, copepods, tardigrades and chironomids also commonly occurred. Three naidid groups, Chaetogaster spp., Nais, bardalis (thick-setae form and normal-setae form) and N. barbata dominated among oligochaetes. Seasonal peaks of population densities in these dominant groups were slightly different from each other. Inspection of gut contents of epiphytic animals and microscopic observation of structure of epiphytic matter suggested that the epiphytic matter supplied not only food but also living space for epiphytic animals.View full abstractDownload PDF (2622K) -
Toshikazu GOTOH, Ken-ichiro NEGORO1986 Volume 47 Issue 1 Pages 77-86
Published: January 30, 1986
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThe diatom community in a less polluted river, the U-kawa River in Kyoto Prefecture, was investigated to find the community characteristics and the relationship between the community and river zonation system based on the geographical features by KAKI (1944). The diatom community was made up of 15-42 forms at each station and characterized by some groups, according to ecological valency in terms of organic pollution, suggesting that the diatom ecological valency by LANGE-BERTALOT (1978, 1979) may be applicable. The dominant species in the community changed from upstream to downstream as follows Gomphonema minutum→Achnanthes convergens→Nitzschia frustulum→Fragilaria vaucheriae var. perminuta, and α-mesosaprobic indicator species in traditional concept were found in this less polluted river. No distinct relationship was also found between the community and river zonation. Species diversity(Shannon-Wiener, DI (bit)) of the communities varied from 1.597 to 4.256 and the communities having lower species diversity were predominated by a blue-green alga, Homoeothrix janthina. The present results indicate that the very high similarity of the diatom communities in different river zones might be due to the dominance of H. janthina which grows over different river zones and forms the uniform microenvironments for diatoms, thus leading to the formation of fairly similar communities.View full abstractDownload PDF (2597K) -
Yasunori WATANABE, Mariyo F. WATANABE, Masayuki WATANABE1986 Volume 47 Issue 1 Pages 87-93
Published: January 30, 1986
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThe species variation and relative abundance of the blue-green alga, Microcystis, were studied with blooming water samples from various eutrophic lakes, reservoirs and ponds. Using the taxonomical system of KOMÁREK (1958), Microcystis aeruginosa f. aeruginosa (M-AA), M. aeruginosa f. flos-aquae (M-AF). M. wesenbergii (M-W) and M. viridis (M-V) were identified. The mode in relative abundance of each species was variable ; M-AA was the most dominant species in 67 %, M-W in 19 %, and M-V in 14 % of the water bodies examined, whereas M-AF was never present as the predominant form. A seasonal shift in the relative abundance was found in Himonya Pond (Tokyo), where M-AA was predominant in the early stage of bloom development, M-W increased in the later period and was present in a higher proportion in the overwintering population in the pond water. The presence of intra species variations and some problems concerning the species identification of the alga were discussed.View full abstractDownload PDF (1671K)
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