Comparison of phytoplankton composition from selected sites in the lower Odra River was done to determine whether the effects of heated water are strongest, from the considered environmental factors. Samples of phytoplankton were collected in April, July and October 2009–2011 at five sites along the lower section of the Odra River. The most pronounced differences between the phytoplankton at the sites were revealed in the phytoplankton abundance and they were related to the time of water retention, the washing out of plankters from slack waters, and the predation by molluscs and zooplankton. The strongest correlations were found between the phytoplankton abundance, the content of inorganic nutrients and temperature. Taxonomic composition of phytoplankton at all sites in the same months was similar. Cooling water from the power plant seems to accelerate eutrophication in the discharge but has no significant impact on the phytoplankton composition downstream in the Odra River.
The study was carried out in the winter of 1999/2000 at the fishing base of the Olsztyn Fishing Farm. The base was comprised of 48 fish cages (15 m³ each) suspended in a post-cooling water canal of the Ostrołęka thermal-electric power station. During the 190 days of observations (31 October 1999 - 15 May 2000), the following factors were analysed: bacteriological contamination of skin, muscle and gastric contents of carp fingerlings produced in cages from summer fry (July fry; 3-5 g body weight). Bacteriological analyses consisted of determining the total count of bacteria cultured on agar (TVC 20 °C and TłVC 37°C), the total count of colic bacteria (Escherichia coli) on Endo medium (Enterobactriacea) and bacteria that is potentially pathogenic to fish and humans (Aeromonas hydrophila, Pseudomonas fluorescens, P. aeruginosa, Staphylococcus aureus). The identification of microorganisms was carried out using the biochemical tests Api 20 NE, Api 2E and Api Staph (bioMérieux). Statistical analysis showed significant differences in the number of all the bacteria assayed between the muscle tissue versus digestive tract and skin mucus. The counts of all the groups of bacteria determined in the carp were permissible and did not exceed Polish hygiene norms.
Within 17 September 31 October 1997, fry of the Russian × Siberian sturgeon hybrid of 31.1 g mean individual weight and sterlet fry of 25.4 g mean individual weight were fed two trout feeds: the Danaex 4.85 and the Safir differing, i.a., in their gross energy content (5470 and 5173 Kcalˇg1, respectively), each feed being offered in triplicate. The fish were kept in cages, stocked at 80 ind./cage, placed in power station cooling water of temperature changing within 12.223°C. Water temperaturedependent differences in fish growth were revealed: the hybrid grew better at 1923°C, while the sterlet growth was better at 1218°C. In both fish groups, the Danaex 4.85 produced better food conversion rate (FCR) and apparent net protein utilisation (aNPU).
Skin mucus and the digestive tract contents of Siberian sturgeon (Acipenser baeri Brandt), feed and water were analyzed during intensive tank rearing. The analyses included the total number of heterotrophic bacteria on common agar at 22°C (TVC 22°C) and 37°C (TVC 37°C), the number of coliforms (TC), fecal coliforms (FC) and fecal streptococci (FS). The water was evaluated for nitrogen cycle bacteria - proteolytic, ammonifying and nitrifying bacteria of phases I and II. The lowest numbers of TVC 22°C (83600 CFU cm⁻³ ) and TVC 37°C (7040 CFU cm⁻³ ) occurred in inflow water. The highest numbers of TVC 22°C (169200 CFU cm⁻³ ) were present in the tanks, while TVC 37°C (7280 CFU cm ⁻³) were the most numerous in outflow water. Statistical analysis confirmed the influence of sturgeon rearing on the densities of these bacteria in the water. No such relationship was detected for sanitary indicator bacteria (TC, FC and FS), the numbers of which did not significantly differ between inflow or outflow water.
The organic pollution and the sanitary state of cooling water used in intensive fish rearing were evaluated. The study was carried out at the cage station of the Olsztyn Fish Farm located in the northeastern Mazurian Lake District of Poland. The water was sampled monthly from April 1 to September 30, 1999. Quantitative analyses included a total count of the bacteria cultured on a common agar medium at 20 and 37°C (TVC 20°C and TVC 37°C), the total count of coliforms (TC) and fecal coliforms (FC), a count of fecal streptococci (FC) and spore-forming anaerobes (Clostridium perfringens). The results obtained indicate that cage fish culture did not considerably affect the bacteriological properties of the water.
Siberian sturgeon weighing 50 ±5 g, cultured in cages stocked at 45 specimens/m3 density and placed in cooling water, were fed Dan-ex 2545 trout feed for 112 days. Experimental treatments differed in the amount of ascorbic acid + glucose mixture (1 : 9) added to the feed. The mixture was applied, in individual treatments, in doses of 0; 1; 5; and 10 g/kg feed, corresponding to ascorbic acid doses of 0; 0.1; 0.5; and 1 g/kg feed. The highest mixture doses resulted in a significant increase in the fish body fat level; however, no significant effect on fish growth was observed.
The Safir trout feed (Aller Aqua) was offered to carp (Cyprinus carpio) fry of 21 + 5 g/ind. initial weight, stocked at a density of 300 ind./m3 in cages placed in cooling water. Identical rations (5 4.0% metabolic weight) were offered for 6, 12, and 18 h per day. The data obtained showed the best results (as indicated by SGR and FCR) of culturing carp of up to about 75 g individual weight were obtained when the feeding took 18 h, 12 18 h being the best duration of feeding for the carp weighing 75 130 g. No effect of duration of feeding was observed in the carp weighing more than 130 g.
W publikacji przedstawiono wyniki badań próbek wody w kierunku wykrywania bakterii z rodzaju Legionella, z przemysłowych obiegów wody chłodniczej oraz systemów klimatyzacyjnych. Na 518 zbadanych próbek, pobranych w okresie od 1998 do 2006 roku, pałeczki Legionella zostały wykryte w 168 próbkach, co stanowiło 32,4% wszystkich zbadanych próbek. Najbardziej niebezpieczna Legionella pneumophila sg 1 była wykrywana w 11,3 % próbek pozytywnych. Niepokój budzi również wysoka liczba wyizolowanych bakterii z rodzaju Legionella (powyżej 103jtk/100ml), którą stwierdzono aż w 60% próbek wody pobranych z systemów wody chłodniczej i w 33% próbek wody związanych z klimatyzacją. Tak wysoki poziom zanieczyszczenia wymaga natychmiastowej interwencji (czyszczenie i dezynfekcja urządzeń). Uzyskane wyniki wskazują na realne zagrożenie zdrowotne jakie związane jest ze skażeniem wód chłodniczych pałeczkami Legionella. Należy zatem dążyć do powstania uregulowań prawnych, które nakładałyby obowiązek monitorowania wód chłodniczych w kierunku bakterii z rodzaju Legionella i prowadzenia odpowiednich działań naprawczych.
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