Acta Hydrochimica Et Hydrobiologica最新文献

{"title":"Comparative Life Table Demography and Population Growth of Brachionus macracanthus DADAY, 1905 and Platyias quadricornis EHRENBERG, 1832 (Rotifera, Brachionidae) in Relation to Algal (Chlorella vulgaris) Food Density","authors":"S. S. S. Sarma, S. Nandini","doi":"10.1002/1521-401X(200211)30:2/3<128::AID-AHEH128>3.0.CO;2-W","DOIUrl":"https://doi.org/10.1002/1521-401X(200211)30:2/3<128::AID-AHEH128>3.0.CO;2-W","url":null,"abstract":"We tested the effect of five different concentrations (0.25 · 106, 0.5 · 106, 1.0 · 106, 2.0 · 106 and 4 · 106 cells mL—1) of the green alga Chlorella vulgaris on the life table demography and population growth of two rotifers (Brachionus macracanthus and Platyias quadricornis). Based on the data from life table studies, we calculated selected survivorship and reproduction variables (age-specific survivorship, life expectancy and stable age distribution, gross reproductive rate, net reproductive rate, generation time and the rate of population increase). In general, both the rotifer species had nearly the same response with increasing food levels as regards the survivorship variables but differed in their reproductive variables. Age-specific survivorship curves were broadly rectangular at lower or intermediate food levels for B. macracanthus while these curves were steep for P. quadricornis. At lower food levels both the rotifer species showed a nearly normal distribution pattern of neonate production. With increasing food levels, both rotifer species showed reduced offspring production. The maximum offspring production was 2.5 ind. female—1 d—1 for B. macracanthus, comparable to P. quadricornis. At the lowest algal food density, the generation time of both the rotifer species was different ((7.12 ± 0.14) d vs (9.87 ± 0.18) d for B. macracanthus vs P. quadricornis, respectively), while at the highest Chlorella level, this was nearly the same. B. macracanthus had higher gross and net reproductive rates than P. quadricornis at any tested food level. The rate of population increase was higher (0.42 to 0.52 d—1) for B. macracanthus than P. quadricornis (0.17 to 0.28 d—1) atany Chlorella level. Statistical analysis of the selected life history variables revealed significant (p 0.05). Data on the population growth of B. macracanthus and P. quadricornis in relation to the five algal densities have also been presented. In general at any given Chlorella level, both B. macracanthus and P. quadricornis showed increased population abundance with increasing food availability. However, B. macracanthus had lower population abundance than P. quadricornis. The lowest peak population density recorded for B. macracanthus was 4.3 ± 0.08 ind mL—1 at 0.25 · 106 cells mL—1, while the highest values (117.3 ± 2.4 ind mL—1) were for P. quadricornis at 4 · 106 cells mL—1. The rate of population increase per day increased with food level for both the rotifer species. However, at any given food level, B. macracanthus had lower growth rates than P. quadricornis. The growth rates ranged from (0.059 ± 0.001) d—1 to (0.11 ± 0.001) d—1 for B. macracanthus and (0.14 ± 0.005) d—1 to (0.21 ± 0.002) d—1 for P. quadricornis. The observed differences in the life history variables of both the rotifer species in relation to food level have been interpreted in terms of species-specific adaptations, based on a combination of life table demography and population growth parameters. \u0000 \u0000 \u0000 \u0000Ve","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"75 1","pages":"128-140"},"PeriodicalIF":0.0,"publicationDate":"2002-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79476336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation on the behaviour of iron, manganese, and phosphate at the sediment/water interface influenced by an electric field","authors":"C. Wolf, R. Fischer, R. Köster, P. Weidler","doi":"10.1002/1521-401X(200211)30:2/3<75::AID-AHEH75>3.0.CO;2-O","DOIUrl":"https://doi.org/10.1002/1521-401X(200211)30:2/3<75::AID-AHEH75>3.0.CO;2-O","url":null,"abstract":"This study presents laboratory experiments for the development of a new, innovative technology for the fixation of iron, manganese, and phosphate in sediments of stagnant waters. The method is intended for the use in lakes and reservoirs, in which high concentrations of iron and manganese in the hypolimnion lead e. g. to a limitation of utilization of raw water for the drinking water production. High phosphate contents released from the sediment can cause eutrophication. \u0000 \u0000 \u0000 \u0000Due to the positioning of an electrode system at the sediment/water interface, a pH and redox barrier is established through electrochemical initiated reactions for the immobilization of iron, manganese, and phosphate. This reaction mechanisms are studied and discussed in a laboratory scale, based on investigations of the sediment, the pore and the overlying water. \u0000 \u0000 \u0000 \u0000It is shown that in the process of the electrochemical polarization first iron and manganese are mobilized from the sediment through anodic proton formation. The dissolved species migrate in the electric field to the sediment/water interface with simultaneous oxidation through anodically produced oxygen (redox-barrier) and are hydrolyzed there. They are accumulated in the pH-barrier as hydroxides/oxyhydroxides/ oxides. Cathodically produced hydroxide ions, which migrate into the opposite direction, form a pH-barrier and prevent the migration of the dissolved iron and manganese ions into the overlying water. Eventually, these reaction processes will generate the accumulation of iron and manganese in sediment layer direct over the anode. \u0000 \u0000 \u0000 \u0000After remediation of the sediment for a period of 3 years it was possible to demonstrate the transformation of amorphous ferric hydroxide phases (Fe(OH)3)to crystalline goethite (α-FeOOH) as well as hematite (α-Fe2O3). \u0000 \u0000 \u0000 \u0000Parallel to the iron and manganese oxidation or precipitation respectively, phosphate from the interstitial, from the water, and from the layer close to the sediment is chemically bound to the iron or aluminium phases. \u0000 \u0000 \u0000 \u0000Untersuchungen zum Verhalten von Eisen, Mangan und Phosphat an der Phasengrenzflache Sediment/Wasser unter dem Einfluss eines elektrischen Feldes \u0000 \u0000 \u0000 \u0000Im Beitrag werden Laborstudien zur Entwicklung eines neuen, innovativen Verfahrens der Fixierung von Eisen, Mangan und Phosphat im Sediment stehender Gewasser vorgestellt. Die Technologie ist fur den Einsatz in Gewassern vorgesehen, in denen hohe Eisen- und Mangankonzentrationen im Hypolimnion zu Nutzungseinschrankungen z. B. bei der Trinkwassergewinnung fuhren oder in denen Eutrophierungserscheinungen infolge erhohter Phosphatrucklosungen aus dem Sediment auftreten konnen. \u0000 \u0000 \u0000 \u0000Durch die Positionierung eines Elektrodensystems an der Phasengrenze Sediment/Wasser wird infolge elektrochemisch initiierter Reaktionen eine Redox- und pH-Barriere zur Immobilisierung von Eisen, Mangan und Phosphat aufgebaut. Im Labormasstab werden diese Reaktionsmechanismen anhand von Untersuchu","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"37 1","pages":"75-86"},"PeriodicalIF":0.0,"publicationDate":"2002-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81398178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reduction of matrix-effects in pesticide analysis with gas chromatography-ion trap mass spectrometry (GC/ITD-MS) by clean-up processes","authors":"F. Mourabit, A. Deger, T. Gremm, A. Ouassini, F. Frimmel","doi":"10.1002/1521-401X(200211)30:2/3<108::AID-AHEH108>3.0.CO;2-3","DOIUrl":"https://doi.org/10.1002/1521-401X(200211)30:2/3<108::AID-AHEH108>3.0.CO;2-3","url":null,"abstract":"In this work analytical determination of some pesticides frequently used in Morocco and Turkey was carried out with solid-phase extraction (SPE) and gas chromatography-ion trap mass spectrometry (GC/ITD-MS). Because of coextracts from the SPE material and/or water sample, recovery values beyond 100 % for some of the selected analytes were observed. This enhanced signal intensity was explained by an enhanced ionisation that is introduced by coeluting sample matrix. A clean-up method using florisil was tested for the removal of matrix substances. The removal of coextracts in the sample after forisil clean-up was proved by a standard addition method. \u0000 \u0000 \u0000 \u0000Probenaufbereitungsschritte zur Verminderung von Matrixeffekten bei der Pestizidanalytik mittels Gaschromatographie-Ion-Trap-Massenspektrometrie (GC/ITD-MS) \u0000 \u0000 \u0000 \u0000In der vorliegenden Arbeit wurde die analytische Bestimmung einiger in Marokko und der Turkei haufig verwendeter Pestizide mittels Gaschromatographie-Ion-Trap-Massenspektrometrie (GC/ITD-MS) nach vorhergehender Festphasenextraktion (SPE) vorgenommen. Aufgrund von Co-Extrakten aus dem Festphasenmaterial und/oder der Wasserprobe wurde fur einige der Analyten eine Wiederfindung von uber 100 % beobachtet. Die verstarkte Signalintensitat wird auf die zusatzliche Ionisierung co-eluierender Matrixbestandteile zuruckgefuhrt. Durch einen Vorreinigungsschritt mit Florisil liesen sich die Matrixbestandteile entfernen, was mit Hilfe der Standardadditionsmethode gezeigt wurde.","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"68 1","pages":"108-116"},"PeriodicalIF":0.0,"publicationDate":"2002-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81660746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reduction of tributyltin (TBT) and other organic pollutants of concern in contaminated sediments by means of an electrochemical oxidation","authors":"H. Stichnothe, A. Keller, J. Thöming, Nina Lohmann, W. Calmano","doi":"10.1002/1521-401X(200211)30:2/3<87::AID-AHEH87>3.0.CO;2-A","DOIUrl":"https://doi.org/10.1002/1521-401X(200211)30:2/3<87::AID-AHEH87>3.0.CO;2-A","url":null,"abstract":"In contaminated sediments butyltin compounds and PAH can be diminished by means of an electrochemical treatment. The butyltin concentrations of the fine fraction (particle size <20 pm) of a mechanical separation unit were reduced from 350 pg/kg to < 10 μg/kg for tetrabutyltin (TeBT), from 2600 μg/kg to <30 μg/kg for tributyltin (TBT), 380 pg/kg to <100 pg/kg for dibutyltin (DBT), and from 570 pg/kg to <100 μg/kg for monobutyltin (MBT), respectively. Furthermore the sum of PAH concentrations for 16 PAH descended approximately 90% during a residence time in the electrolysis cell of 3 h, while in contrast PCB concentrations remained the same before and after the treatment. Apparently, the presence of PCB limited the application of this process, if the initial concentration exceeded guideline values for relocation. Further investigations have to be undertaken to clarify this point. Nevertheless the promising results obtained from a technical treatment unit have led to the construction of a pilot plant, which is installed in Bremen and operating since the beginning of 2002.","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"41 1","pages":"87-93"},"PeriodicalIF":0.0,"publicationDate":"2002-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74953741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photochemical Degradation of Organic Carbon in Acidic Mining Lakes","authors":"K. Friese, P. Herzsprung, B. Witter","doi":"10.1002/1521-401X(200211)30:2/3<141::AID-AHEH141>3.0.CO;2-F","DOIUrl":"https://doi.org/10.1002/1521-401X(200211)30:2/3<141::AID-AHEH141>3.0.CO;2-F","url":null,"abstract":"The investigated coal mining lakes of the Lusatian lignite mining district and the mid-German lignite district are geogenically acidified caused by pyrite and marcasite oxidation. All lakes are characterized by high ionic strength and extremely high concentrations of dissolved ferric iron. In oxic water layers, up to 10% of total iron is present as Fe(II). Mean concentrations of dissolved organic carbon (DOC) are extremely low in the investigated Lusa-tian lakes (<0.1 mmol/L). During summer months, DOC concentrations below the detection limit were observed in epilimnetic layers accompanied by increased concentrations of ferrous iron. It is suggested that photochemical reactions are responsible for depletion of DOC and formation of ferrous iron as it has been described for acidic soft-water lakes. The coupling of DOC degradation and ferrous iron production was verified with sunlight exposure experiments. Samples of acidic mining lakes were irradiated in quartz glass vessels. Up to 50% of DOC was transformed to CO2 after 300 min of irradiation with natural sunlight, and the light-induced production of Fe(II) was up to 450% (compared to 100% Fe(II) concentration before irradiation). \u0000 \u0000 \u0000 \u0000As a consequence of acidification and photochemical reactions, the carbon budget of investigated mining lakes is kept low because organic carbon is finally oxidized to carbon dioxide which leaves epilimnetic water layers as a gas. \u0000 \u0000 \u0000 \u0000Photochemischer Abbau von organisch gebundenem Kohlenstoff in sauren Bergbaurestseen \u0000 \u0000 \u0000 \u0000Die untersuchten Bergbauseen der Braunkohlenabbaugebiete des Lausitzer Braunkohlenreviers und des mitteldeutschen Braunkohlenreviers sind durch Pyrit- und Markasitoxidation geogen versauert. Alle Seen sind durch hohe Ionenstarken und extrem hohe Konzentrationen an gelostem Eisen(III) charakterisiert. In oxischen Wasserschichten liegen bis zu 10% des Gesamteisens als Eisen(II) vor. Die Konzentrationen von gelostem organischen Kohlenstoff (DOC) sind in den untersuchten Seen der Lausitz meist extrem niedrig (< 0.1 mmol/L). Wahrend der Sommermonate liegen die DOC-Konzentrationen im Epilimnion unterhalb der Nachweisgrenze und werden von ansteigenden Konzentrationen an Eisen(II) begleitet. Es ist zu vermuten, dass photochemische Reaktionen, wie sie fur saure Weichwasserseen beschrieben wurden, fur diese Verarmung an DOC und die Bildung von Eisen(II) verantwortlich sind. Der Zusammenhang zwischen dem DOC-Abbau und der Eisen(II)-Bildung wurde mit Sonnenlicht-Experimenten bestatigt. Proben aus sauren Bergbauseen wurden in Quarzglasgefasen bestrahlt. Bis zu 50% des DOC wurde nach 300 Minuten Bestrahlung mit naturlichem Sonnenlicht zu CO2 transformiert und die Lichtinduzierte Bildung von Eisen(II) machte bis zu 450% aus (bezogen auf 100% Eisen(II)-Konzentration vor der Bestrahlung). \u0000 \u0000 \u0000 \u0000Als Konsequenz der Versauerung und der photochemischen Reaktionen bleibt das Kohlenstoffbudget der untersuchten Bergbauseen niedrig, da der organische Kohlenstoff l","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"57 1","pages":"141-148"},"PeriodicalIF":0.0,"publicationDate":"2002-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76419151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Field Study on the Hydrochemistry of Land/Inland Water Ecotones with Reed Domination","authors":"Weidong Wang, Dali Wang, C. Yin","doi":"10.1002/1521-401X(200211)30:2/3<117::AID-AHEH117>3.0.CO;2-3","DOIUrl":"https://doi.org/10.1002/1521-401X(200211)30:2/3<117::AID-AHEH117>3.0.CO;2-3","url":null,"abstract":"The hydrochemistry of land/water ecotones dominated by a reed (Phragmites australis) community was studied in a eutrophic shallow lake in China. The ecotones are composed of reed beds divided by many artificial ditches and serve as a connecting link between the upstream Fuhe River mouth and the downstream central lake. This lake-side ecotone exhibited a strong chemical buffering function and high nutrient removal processes. In the subsurface water of reed beds, the partial CO(2) pressure was 23...704 times of that in the atmosphere and the partial O(2) pressure was 5...34% of atmospheric O(2) pressure. The change of hydrochemical type and greatest nutrient reduction occurred at 0.5 m landward from the reed-bed/ditch boundary. The dominant cations in ditch water and subsurface water were Na(+) and Ca(2+), respectively. The nutrient level in the reed-bed subsurface water maintained low and stable despite the variable high concentrations of nutrients in the ditch water. The crisscrossed reed-bed/ditch landscape greatly increases the active area between eutrophic river mouth water and subsurface water. Since the area of reed fields in the lake occupies 22% of the lake area, the exchange between the subsurface water of reed beds and ditches can act as a huge buffer to reduce allochthonous nutrient input and the nutrient concentrations in the lake. Thus, the self-purification capacity of the lake ecosystem increased with the presence of an active ecotone.","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"25 1","pages":"117-127"},"PeriodicalIF":0.0,"publicationDate":"2002-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77599720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coupling of Electrochemical and Biological Treatment To Remove Diethylenetriaminepentaacetic Acid (DTPA) from Pulp and Paper Effluents","authors":"C. G. Ginkel, B. Tuin, V. Aurich, W. Maassen","doi":"10.1002/1521-401X(200211)30:2/3<94::AID-AHEH94>3.0.CO;2-Q","DOIUrl":"https://doi.org/10.1002/1521-401X(200211)30:2/3<94::AID-AHEH94>3.0.CO;2-Q","url":null,"abstract":"To enhance the biodegradability of diethylenetriaminepentaacetic acid (DTPA), effluents containing this chelating agent were electrochemically treated. Electrochemical pretreatment effectively fragmented DTPA into biodegradable compounds as demonstrated by increased BOD/ThOD ratios. The presence of other organic compounds reduced the rate of electrochemical DTPA degradation, but less than proportionally, indicating that DTPA degradation is partially selective. Finally, an experiment was performed to assess removal of DTPA under the conditions of an activated sludge plant treating pulp and paper effluent. The combined electrochemical and biological treatment resulted in an overall removal of 70 % of DTPA nitrogen. The combined processes degraded more than 95 % of the DTPA. \u0000 \u0000 \u0000 \u0000Verfahrenskombination aus elektrochemischer und biologischer Behandlung zur Entfernung von Diethylentriaminpentaessigsaure (DTPA) aus Abwassern der Zellstoff- und Papierindustrie \u0000 \u0000 \u0000 \u0000Um die biologische Abbaubarkeit von Diethylentriaminpentaessigsaure (DTPA) zu verbessern, wurden Abwasser, die diesen Chelatbildner enthalten, elektrochemisch behandelt. Durch die elektrochemische Vorbehandlung wurde DTPA tatsachlich in biologisch abbaubare Verbindungen zersetzt, wie sich an hoheren Werten des BOD/ThOD-Verhaltnisses zeigte. Wenn andere organische Verbindungen vorhanden waren, ging der Umfang der elektrochemischen Zersetzung von DTPA zuruck, jedoch unterproportional, so dass der Abbau von DTPA teilweise selektiv zu erfolgen scheint. Schlieslich wurde versucht, den Abbau von DTPA unter den Bedingungen einer Belebtschlammanlage abzuschatzen, in der Zellstoff- und Papierabwasser behandelt wurden. Die Kombination der elektrochemischen und der biologischen Behandlung ergab insgesamt einen Abbau von 70 % des DTPA-Stickstoffs. Die beiden Prozesse gemeinsam fuhrten zu einem Abbau der DTPA von uber 95 %.","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"76 1","pages":"94-100"},"PeriodicalIF":0.0,"publicationDate":"2002-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85563094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Four Species of Cladocerans (Crustacea) on the Population Growth of Brachionus patulus (Rotifera)","authors":"S. Nandini, S. S. S. Sarma, M. D. Hurtado-Bocanegra","doi":"10.1002/1521-401X(200211)30:2/3<101::AID-AHEH101>3.0.CO;2-V","DOIUrl":"https://doi.org/10.1002/1521-401X(200211)30:2/3<101::AID-AHEH101>3.0.CO;2-V","url":null,"abstract":"In freshwater ecosystems, rotifers and cladocerans often dominate, in terms of both, numbers and biomass. However, between these groups, competition leads to an inverse relation. We quantified the effect of cladocerans (at fixed density = 0.5 ind mL—1; and biomass = 9.6 μg mL—1 (dry weight)) on the population growth of Brachionus patulus, using Daphnia pulex, Simocephalus vetulus, Moina macrocopa, and Ceriodaphnia dubia at 0.5 · 106 cells mL—1 and 1.5 · 106 cells mL—1 of Chlorella vulgaris. The initial density of rotifers in the controls and in the mixed cultures was 5 ind mL—1, while the density and the biomass of cladocerans (experiments conducted separately) was kept constant. Our results showed that regardless of food density, the presence of cladocerans had a significantly negative effect on the maximal population density and the rate of population growth of B. patulus. Control rotifer populations increased with increasing food density. Population density of B. patulus was least affected by Ceriodaphnia dubia, while the maximum negative effect was caused by the presence of Daphnia pulex. The rate of population increase per day (r) of B. patulus in controls was (0.27 ± 0.01) d—1 and (0.32 ± 0.01) d—1 under low and high food levels, respectively. The r values were negative in the presence of D. pulex regardless of food density while in the presence of S. vetulus, a negative r value was obtained only at the lower food level. \u0000 \u0000 \u0000 \u0000Einfluss von vier Cladoceren-Arten auf das Populationswachstum von Brachionus patulus (Rotifera) \u0000 \u0000 \u0000 \u0000In Okosystemen des Suswassers dominieren oft Rotatorien und Cladoceren, sowohl in der Anzahl wie in der Biomasse. Konkurrenz zwischen diesen Gruppen fuhrt jedoch zu einer inversen Beziehung. Untersucht wird der Einfluss von vier Cladoceren-Species (Daphnia pulex, Simocephalus vetulus, Moina macrocopa und Ceriodaphnia dubia) bei konstanter Dichte (0.5 Ind. mL—1, 9.6μg mL—1 (Trockenmasse)) auf das Populationswachstum von Brachionus patulus bei einem Nahrungsangebot von Chlorella vulgaris mit 0.5 · 106 Zellen mL—1 und 1.5 · 106 Zellen mL—1. Die initiale Dichte von Brachionus in den Kontrollen und gemischten Kulturen betrug 5 Ind. mL—1, wahrend die Dichte und Biomasse der Cladoceren in den Experimenten konstant gehalten wurden. Die Ergebnisse zeigen, dass — unabhangig von der Nahrungsdichte — die Anwesenheit der Cladoceren einen signifikant negativen Effekt auf die maximale Populationsdichte und das Populationswachstum von B. patulus hat. Im Kontrollexperiment nahm die Rotatorien-Population mit steigender Nahrungsdichte zu. Die Populationsdichte von B. patulus wurde von Ceriodaphnia dubia am geringsten, durch Daphnia pulex am starksten beeinflusst. Die Wachstumsrate r von B. patulus betrug in den Kontrollen (0.27 ± 0.01) d—1 bzw. (0.32 ± 0.01) d—1 bei geringer bzw. hoher Futterdichte. Die r-Werte waren bei Anwesenheit von D. pulex unabhangig von der Futterdichte negativ, bei Anwesenheit von S. vetulus wurde ein negativ","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"39 1","pages":"101-107"},"PeriodicalIF":0.0,"publicationDate":"2002-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76495030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cryptosporidium and Giardia in natural, drinking, and recreational water of Northwestern Greece","authors":"P. Karanis, C. Papadopoulou, A. Kimura, E. Economou, C. Kourenti, H. Sakkas","doi":"10.1002/1521-401X(200207)30:1<49::AID-AHEH49>3.0.CO;2-R","DOIUrl":"https://doi.org/10.1002/1521-401X(200207)30:1<49::AID-AHEH49>3.0.CO;2-R","url":null,"abstract":"An investigation about distribution of Giardia cysts and Cryptosporidium oocysts in natural, drinking, and recreational water in Northwestern Greece was performed. Five rivers (Aoos, Arachthos, Kalamas, Louros, and Voidomatis) and one lake (Pamvotis Ioannina Lake) in Northwestern Greece were investigated during a 10-month period. Drinking and recreational water (swimming pools) from the area were also examined. Samples were collected from prefixed sampling stations and processed following a modification of standard methods for the microbiological examination of water, as suggested by the APHA/AWWA/WEF. Both Giardia cysts and Cryptosporidium oocysts were isolated from Pamvotis Ioannina Lake (15 positive/27 examined samples). Significantly lower numbers of Cryptosporidium oocysts were detected in Arachthos River (1/5), Voidomatis River (1/5), drinking water (1/7), and pool water samples (1/9). No Giardia cysts were detected, neither in river water, nor in drinking, and pool water samples. The results clearly show that, with the exception of Pamvotis Ioannina Lake, where contamination of high level was observed, natural water sources of the investigated area have low pollution, resulting in low contamination with parasites.Cryptosporidium und Giardia in Roh-, Trink- und Schwimmbadwasser in Nord-West-GriechenlandEs wurden Untersuchungen uber das Vorkommen von Giardia-Zysten und Cryptosporidium-um-Oozysten in Roh-, Trink- und Schwimmbadwasser in Nord-West-Griechenland durchgefuhrt. Funf Flusse (Aoos, Arachthos, Kalamas, Louros und Voidomatis) und ein See (Pamvotis) wurden in einen Zeitraum von 10 Monaten untersucht. Es wurden auch Trink- und Schwimmbadwasserproben entnommen und untersucht. Die Proben wurden in ausgewahlten Stationen entnommen und mit einer modifizierten Standardmethode (APHA/ AWWA/WEF) fur die mikrobiologische Untersuchung des Wassers verarbeitet. Sowohl Giardia-Zysten als auch Cryptosporidium-Oozysten wurden aus dem Pamvotis Ioannina See isoliert (15 positive/27 untersuchte Proben). Deutlich niedrigere Konzentrationen von Cryptosporidium-Oozysten wurden in Arachthos (1/5), Voidomatis (1/5), Trink- (1/7) und Schwimmbadwasser (1/9) nachgewiesen. Keine Giardia-Zyste wurde in Fluss- und Trinkwasser oder in Schwimmbadern gefunden. Die Ergebnisse zeigen eindeutig, dass mit Ausnahme vom Pamvotis Ioannina See, wo hohe Kontaminationen beobachtet wurden, Rohwasserquellen aus dem untersuchten Gebiet leicht belastet und mit Parasiten kontaminiert sind.","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"11 1","pages":"49-58"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87731101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abschätzung und Beeinflussbarkeit der Arsenmobilität in kontaminierten Böden","authors":"Franka Dankwarth, J. Gerth","doi":"10.1002/1521-401X(200207)30:1<41::AID-AHEH41>3.0.CO;2-1","DOIUrl":"https://doi.org/10.1002/1521-401X(200207)30:1<41::AID-AHEH41>3.0.CO;2-1","url":null,"abstract":"Die Sickerwasserkonzentration in arsenkontaminierten Rieselfeldboden eines ehemaligen Gerbereistandortes wird durch Schuttel- und Saulenversuche abgeschatzt. Zusatzlich wird der Einfluss reduzierender Verhaltnisse, des pH-Wertes und der Ionenstarke berucksichtigt. Der eisenreiche Unterboden (C-Horizont) stellt die Hauptquelle fur eine Belastung des Grundwassers mit Arsen dar. Hier ist bei starkerer Durchfeuchtung zeitweise mit reduzierenden Verhaltnissen und einer erhohten Mobilisierung zu rechnen. Die potentiell freisetzbare Arsenfraktion wird daher durch Auflosen der leicht reduzierbaren Eisenoxidfraktion mit 0.1 M Ascorbinsaure naherungsweise erfasst. Die Arsenkonzentration in der Losung lasst sich durch Erhohung der Ionenstarke (z. B. mit 0.01 M CaCl2-Losung) von uber 100 μg/L auf unter 20 μg/L stabilisieren. Arsenkontaminierte Boden sollten mit CaCO3 behandelt werden, um eine moglichst hohe Calciumkonzentration in der Bodenlosung zu erzielen. Die Arsenkonzentration im Sickerwasser wird in erster Linie durch Sorptionsprozesse gesteuert und nicht durch Losungs- und Fallungsprozesse. \u0000 \u0000 \u0000 \u0000Assessment and Modification of Arsenic Mobility in Contaminated Soil \u0000 \u0000 \u0000 \u0000Arsenic concentration in the seepage of contaminated soils of an old tannery site is assessed using batch and column experiments. The effect of reducing conditions, pH, and ionic strength is also investigated. The iron oxide rich subsoil (C-horizon) is the main source of groundwater pollution with arsenic. In this horizon, mobilization can increase as a result of reducing conditions upon periodical water saturation. Therefore, the potentially mobile arsenic is determined by a reductive dissolution of the poorly crystalline iron oxide fraction using 0.1 M ascorbic acid. Arsenic concentration can be reduced from 100 μg/L to below 20 μg/L by an increase of ionic strength (e.g. by a 0.01 M CaCl2 solution). Arsenic contaminated soils should be limed regularly in order to maintain the highest possible calcium concentration in the soil solution.","PeriodicalId":7010,"journal":{"name":"Acta Hydrochimica Et Hydrobiologica","volume":"4 1","pages":"41-48"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78688372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}