Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 32

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
This work presents the results of research on quantitative and qualitative composition of heterotrophic bacteria in waters from 11 wells and 3 piezometric bore-holes in Omulewski Reservoir Aquifer before liquidation of large cattle and swine farms (in 1989-1991) and after their liquidation (1994-1995). Examinations concerning the number of indicatory heterotrophic microorganisms on TGY medium showed fluctuations in the number (from some to several thousand CFU/1 cm3 of water) depending on the way of utilization of the soil and the research period. Gram-negative rods (44-79%) dominated in 241 water samples taken from wells and piezometric bore-holes in both research periods. Gram-positive coccus (3-32%) and cells rod-shaped (3-19%) were not so numerous. The strains: Achromobacter, Flavobacterium and Xanthomonas dominated among Gram-negative bacteria irrespective of the research period and group of wells. Gram-positive bacteria were mainly represented by: Bacillus, Sarcina and Micrococcus.
Studies were carried out on the content of NH4-N, NO2-N, NO3-N and numbers of bacteria indicatory of water pollution (TVC 20 degreesC, TVC 30 degreesC) and its sanitary state (TC, FC, FS) in deep wells and shallow piezometric boreholes, as well as on bacteriological contamination of water in rivers Sawica and Omulew, in the area of water-bearing formations of Omulewski Aquifer (with no isolation from the surface), in 1995-1997 (after liquidation of the majority of large cattle and pig breeding farms in this area). The following were distinguished: 1. wells in afforested area in Sedansk and Narty, 2. wells located in farm lands of individual farmers in Jedwabno and Kot, 3. wells located in breeding farms of foxes, cattle and pigs in the villages Janowo, Dzierzki, Wesolowo, Wielbark, Przezdziek, Baranowo, Wyzegi, and 4. piezometric boreholes in the cattle farm at Wesolowo. Water of Sawica River (together with water from trout ponds fed by this river) and of Omulew River were analyzed at Janowo, Kot, Wesolowo and Wielbark, close to respective wells and boreholes. The degree of chemical and bacteriological contamination of well waters was diversified, depending on current and earlier use of land in the area of Omulewski Aquifer. NH4-N content decreased in well and borehole waters located in the area of former cattle and pig farms at Dzierzki, Wesolowo, Przezdziek, Baranowo and Wyzegi compared to the levels found in 1989-1993. Notwithstanding this, its level in some wells exceeded 0.5 mg/l NH4-N, i.e. the maximum level permissible in drinking water and water used for household purposes. As regards the sanitary state, only wells in Sedansk conformed to the standards for drinking and household water. Contrarily to what was expected, there was no decrease of indicatory bacteria numbers in water of wells and boreholes located in the area of former large cattle and pig farms. Water in deep wells at Kot, Wesolowo and Wielbark usually contained higher numbers of indicatory bacteria in the periods when their levels increased also in Sawica and Omulew rivers.
The investigation was carried out in the “Seven Islands” nature reserve. It has been discovered that in the spring, summer and autumn the number of determined pollution degree indicator bacteria (TVC 22°C and TVC 37°C) of the water of Lake Oświn ranged from tens to thousands of CFU per 1 ml, depending on the research station. The sanitary state indicator bacteria (TC, FC, FS) occurred from single cells to several hundred thousand cells per 100 ml of water. In 36.5% of the lake water samples, the FC:FS ratio was determined as higher than 4.0, but it also ranged from 0.7 to 4.0. In 18% of Lake Oświn water samples it ranged from 0.043 to 0.7, and in 9% it was lower than 0.043. This proves excretal contamination with prevailing excrements of human origin.
The paper was aimed at synthetic presentation of results of own studies into the occurrence and function of Aeromonas hydrophila bacteria in aquatic environments with different degrees of contamination. This species belongs to the class of gamma proteobacteria, the order of Aeromonadales and the family of Aeromonadaceae. Results of own long-term studies confirm the thesis on the ubiquity of A. hydrophila bacteria, whose occurrence reflects the trophy and contamination degree of aquatic environments, especially. Despite the relatively low numbers of these microorganisms, in environmental studies their percentage in the total bacteria count reached up to 30% in water samples and even up to 41.5% in fish samples. Taking all this into account, it seems justified to consider A. hydrophila bacteria as a potential indicator in the anthropogenic contamination of waters.
This work describes bacteriological studies on the quantitative and qualitative composition of bacteria from the family Enterobacteriaceae as well as numbers of Pseudomonas aeruginosa and Aeromonas hydrophila in underground waters of the Omulewski Reservoir, a source of water for consumption. In 1994-1995 studies were carried out on 11 deep wells and 3 piezometric holes. Bacteria from the family Enterobacteriaceae were found in amounts from a few to many colonies (cfu/100 ml), depending on the sampling station and the method of land use (groups of wells). In the entire study period and usually in all wells the following dominated: Citrobacter freundii, Ervinia herbicola, Escherichia coli, Proteus vulgaris, and Serratia marcescens. Pseudomonas aeruginosa and Aeromonas hydrophila were present in small amounts in the majority of water samples (from a few to several colonies) and only when large quantities of water were collected (100 ml).
Sanitary and bacteriological studies were conducted during European catfish (Silurus glanis L.) wintering from January 3, 2001 to March 7, 2001. Samples of water, skin and digestive tract contents were collected every two weeks. Qualitative analyses included culturing heterotrophic bacteria on a broth-agar medium at temperatures of 4ºC for 7 days of incubation (TVC 4ºC), 22°C for 72 hours of incubation (TVC 22°C) and 37°C for 24 hours of incubation (TVC 37° C). The total number of coliforms (TC), the total number of fecal coliforms (FC) and the total number of fecal streptococci (FS) were determined. The results obtained confirmed that the sanitary and bacteriological state of the water in the wintering pond was good. The number of microbes per cm² of skin varied from 10³ to 10⁴ , and in 1 g of digestive tract contents from 10³ to 10⁵ .
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.