摘要:

AbstractPresented is an analytical method which enables a quick determination of the total cation content in water. In this method, total alkalinity is determined before passage, and mineral acidity after passage through the ion exchange bed. The sum of the two parameter values gives the total cation content in the water. Verification was carried out with model solution and natural water samples. The method makes it possible to verify the ion balance of the electrolytes, as well as to determine the salinity level (i.e. the concentration of dissolved substances) in the sample.

ISSN:0323-4320    

DOI:10.1002/aheh.19890170502

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0323-4320    

DOI:10.1002/aheh.19890170503

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractWith the aid of the Soviet atomic‐absorption two‐channel spectrometer “Saturn” successful attempts were made to improve the sensitivity of the heavy‐metal determination after the previous two‐step separation and concentration technique. Compared with other combustible gases, the propane/nitrogen‐oxide flame is preferred. Because of the possibility of the direct determination of the heavy metals in the water samples the duration of analyses could be reduced by fifty per cent. Besides the heavy‐metal analytics, a rapid‐determination technique for calcium and magnesium was developed. The results of the different determination techniques and the ranges of measurement are given

ISSN:0323-4320    

DOI:10.1002/aheh.19890170504

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThe limnological state analysis includes investigations of the physical‐chemical state and of the macroflora as well as of the plankton of the lakes Grosser Serrahn, Haussee, Schweingartensee and Zwirnsee in the years of 1983 to 1987. Grosser Serrahn and Haussee are eutrophic lakes with a considerably differentiated development and a consistent dystrophic character due to bogs in the surrounding area. During the last years, lake Schweingartensee has shown a pronounced increase in trophy with development of cyanophyceae all the year round. Zwirnsee as well as Hinnensee and Fürstenseer See are mesotrophic lakes with considerable quantities of characeae. In the three mesotrophic lakes, Coregonus albula still reproduces its population sufficiently. The results allow us to draw conclusions with respect to the guidelines for the treatment of the Serrahn nature reserve, especially for the preservation of the quality of wate

ISSN:0323-4320    

DOI:10.1002/aheh.19890170505

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0323-4320    

DOI:10.1002/aheh.19890170506

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThe small eutrophic man‐made lake in Wadi el Majanin, Libya has a well‐buffered hydrogen‐carbonate (98 … 160 mg/l CaCO3) system (pH = 7 … 7.8) and a poor Secchi visibility (21 … 35 cm). Conductivity data (272 … 480 μS/cm) fit the water‐body in class 2 (‘freshwater’ range) of Beadle. The annual surface water temperature cycle (before noon readings) showed strong seasonal variations from 12 °C in Jan. and Feb. 1986 to 28.5 °C in June, 1987. The lake sustains a good crop of plankton populations. The main phytoplankton were species ofPediastrum, Scenedesmus, Navicula, Amphora, Synedra, Gomphonema, Oscillatoria, Gomphosphaeriaand from zooplankton these wereKeratella, Polyarthra, Brachionus, Moina, Acanthocyclopsand nauplii of copepods. The presence of euglenoids supports the enriched water status of the ecosystem. Planktonic algal flora appeared closer to the eutrophic chlorococcales‐diatom type (Hutchinson). Rotifers dominated the zooplankton community. A well established macrophyti

ISSN:0323-4320    

DOI:10.1002/aheh.19890170507

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractTotal soluble carbohydrate, individual sugars and starch content in green shoots ofCeratophyllum demersum, Elodea canadensis, Myriophyllum exalbescens, Potamogeton foliosusandP. zosteriformisfrom Shoal Lake (Manitoba‐Ontario) were examined in relation to tissue chlorophyll content, water chemistry and temperature. The different species showed a variety of seasonal carbohydrate patterns. Seasonal concentrations of total soluble carbohydrate were significantly positively correlated with chlorophyll and total chlorophyll a + b inE. canadensisandP. foliosus.Seasonal starch content was inversely correlated with chlorophyll a and total chlorophyll a + b inC. demersumandP. foliosus.InC. demersumnonstructural carbohydrate was inversely correlated with total alkalinity, total molybdenum reactive phosphorus, total inorganic nitrogen and temperature of the water. Sucrose concentrations inP. foliosusin June were positively correlated with phosphorus levels in the wate

ISSN:0323-4320    

DOI:10.1002/aheh.19890170508

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractExperiments to study the influence of biomass concentration and pH on copper uptake by blue‐green algae were performed. Differential pulse anodic stripping voltammetry (DPASV) was used for copper analysis. The maximum copper uptake per unit of biomass depends only on copper concentration and not on biomass concentration. Hence the copper toxicity is independent of biomass over a wide range. A main factor influencing copper uptake is the pH. Whereas the copper uptake ofAphanizomenon gracileis rapid at pH = 8.2 we did not find a significant uptake at pH = 5.7. The copper uptake at the higher pH value is followed by a nearly complete release of this copper, accompanied by a fast shortening of trichomes. There was no significant copper uptake inOscillatoria redekeiat pH = 8.2, but at pH = 7.2 the uptake pattern of this species is similar to that ofAphanizomenonat pH = 8.2. The results suggest that the metal ion uptake mechanisms of different species have not the same pH optim

ISSN:0323-4320    

DOI:10.1002/aheh.19890170509

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThe aim of this work was to find out how far the Nervion Estuary serves as a reservoir of R plasmids and/or for their dissemination. The fecal pollution bacterial indicator population was estimated along the estuary and 167 coliform isolates were assayed for resistance to 16 antibiotics. About sixty‐nine per cent of the coliform isolates were antibiotic‐resistant and forty‐two per cent of these were simultaneously resistant to three or more of 16 antibiotics tested. Furthermore, 31.5% of enterobacterial strains resistant to any of the antibiotics tested could transfer their resistance determinants in conjugal matings. Most of the transferred plasmids confer resistance to ampicillin or to other β‐lactamic antibiotics and several codify resistance to tetracyclin, chloramphenicol of fosfomycin. Taking account of the coliforms density found and the ratio of these isolates able to transfer R plasmids, an average of 5 × 103coliform strains able to transfer R plasmids in 100 ml of water was obtained. This amount must indicate a significant potential public health risk because these polluted waters get into an area with intensive fishing and recreat

ISSN:0323-4320    

DOI:10.1002/aheh.19890170510

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0323-4320    

DOI:10.1002/aheh.19890170511

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY