Radioautographic method of determination of number of bacteria in water-bodies [Translation from: Informatsionnyi Byulleten Biologiya Vnutrennikh Vod No.26, 65-67, 1975]

The radioautographic method of determination of the number of autotrophic microorganisms was initially suggested for counting methane-oxidizing bacteria. With the help of this method colonies of hydrogen-oxidizing bacteria are differentiated even more clearly from heterotrophic. Under laboratory conditions it was shown that colonies grown on membrane filters from a pure culture of thionic bacteria on a nutrient medium with radio- active carbonate, give better prints on film. This method was tested by the authors for determining the number of these bacteria in the meromictic Lake Vae de San Juan during the expedition to Cuba in the summer of 1973. The study showed that that the thionic bacteria are found throughout the pelagial. It proved that the thionic bacteria can be well considered in water-bodies by the radioautographic method.

A rapid and simple method for the determination of Formaldehyde in Fishery Products

The content of free formaldehyde (FA) in minced fish muscle was measured by the following procedure: A mixture of minced fish muscle and water was deproteinized by means of the Carrez reagent. The FA content of the filtrate was determined reflectometrically using the Reflectoquant test strips and the RQflex. The results agreed well with the colorimetrically (Nash test) measured FA content. Der Gehalt an freiem Formaldehyd (FA)in Fischerzeugnissen wurde mit folgender Methode bestimmt: Zerkleinertes Fischfleisch wurde mit Wasser homogenisiert und mit Carrez-Reagenz enteiweißt. Der Formaldehydgehalt des Filtrates wurde reflektometrisch unter Verwendung von Reflectoquant-Teststätbchen und des RQflex ermittelt. Die Ergebnisse stimmten gut mit kolorimetrisch (Nash Test) gemessenen FA-Gehalten überein.

Aluminium in Fisch und Fischereierzeugnissen

Recent reports associating aluminium with several skeletal (osteomalacia) and neurological disorders (encephalopathy and Alzheimer’s disease) in humans suggest that exposure to aluminium may pose a hazard to health. This requires the examination of aluminiumcontent in different foodstuffs. Therefore, an analytical method for the determination of aluminium in fish and fishery products, especially in fishery products packaged in aluminium cans, was developed using graphite furnace atomic absorption spectrometry. Fillets of lean and fatty fish showed aluminium levels lower than 1mg/kg wet weight, muscle of crustacean, molluscan and shellfish had apparently higher aluminium levels (up to 20 mg/kg wet weight). The aluminium content in some aluminum-canned herring was much higher than the content found in herring caught in the North Sea. These results indicate that aluminium is taken up by the herring fillets in aluminium cans, presumably through the slight and slow dissolution of aluminium from the can wall, due to some defects in the protective lacquer layer. A comparison of the aluminium levels measured in canned herring with the average aluminium-intake (normally between 3 and 5 mg/day) or with the provisional tolerable daily intake of 1mg/kg body weight per day (WHO 1989) indicated, that the aluminium content of the edible part of aquatic food does not play a significant role. High consumption of fish fillets does not pose any health risk.

On a method of determination of chlorophyll in cells of algae collected on a membrane filter. [Translation from: Trudy Instituta Biologii Vnutrennykh Vodnany 11(14), 198-202, 1966.]

The original method, proposed by Yentsch (1957), of determination of chlorophyll directly in the cells, attracts attention by its simplicity. In order to measure the content of chlorophyll by this method, a determined volume of suspension of algae is filtered through a membrane filter. The latter is dried a little, clarified by immersion oil, clamped between two glasses, and spectrophotometrized. Extinction is read off at , wavelengths equal to 670 millimicrons (around the maximum absorption of chlorophyll a in the cell) and 750 millimicrons (correction for non- specific absorption and dispersion of light by particles of the preparation). The method of Yentsch was employed by the authors for determination of chlorophyll-a in samples of phytoplankton. They conclude that in spite of the simplicity and convenience of determination the method must be applied sufficiently carefully. It is more suitable for analysis of cultures of algae, where, non-specific absorption of light is insignificant.

The residue measurment of pesticide in water and biota of the Sorkhrood River in the south of the Caspian Sea

Pesticide residue is considered as a crucial factor in the fresh water ecosystem pollution of north Iran (Esp. Gillan and Mazandaran provinces). It is also regarded dangerous to the health of human being and animals. In this research , pesticide residue in 3 species of fish was gauged in stations of the Haraz river , the Sorkhrood river , and the Caspian sea. The sampeles were taken during 27 mounths (started in April 97 and ended to June 99). The maximum level of pesticide in water was found in July 98 for lindine at 12.4 ppb. The level of chlorinated pesticide residue recorded at 63 ppb in April 98. The level of. organophosphorus pesticides residue in water was at 1.75 ppb in Aug 97. The toxicity of the mentioned pesticide and bioaccomulation were taken into account in conducting this researched.

Nitrogen and phosphorus forms in water and the food requirements of algae. [Translation from: Wiadomosci Ekologiczne 19 238-244, 1973. ]

When dissolved in water, compounds of nitrogen and phosphorus ought to contain the basic assimilated food requirements for autotrophic plants and therefore autotrophic algae. This article summarises the occurrence of nitrogen in water, how species of algae utilize nitrogen and phosphorus forms for growth and the capacities of algae to adapt to environments of different nutrient wealth. This topic has unquestionable importance not only for the purpose of survival of a species but also in deciding indirectly about the stability of ecosystems.

The effect of oxygen concentration in water on the growth and nitrogen metabolism in the fry of rainbow trout [Translation from: Rybnoe Khoziaistvo,V.33, 74-75, 1957]

To ascertain the effect of various concentrations of oxygen in water on the fry of rainbow trout experiments were made with aquaria at various concentrations of oxygen. The food supplied was chironomid larvae (Chironomus plumosus). A surplus of food was supplied to the fry. Indices are given of the reaction of the fry to different temperatures.

Distribution of mercury in a tropical estuary (India) situated near a chloro-alkali plant

The distribution of mercury in water, sediment and some biological samples of the Rushikulya estuary, east coast of India were assessed during Jan-Dec. 1989. Both the dissolved plus acid leachable mercury contents in water and the sediment mercury discerned conspicuous spatial and seasonal fluctuations. Adsorption on to the suspended particulates was found to be the most likely mechanism for removal of mercury from the water column. Exchange of mercury from sediments to water was observed at high salinities (20-30x10-3). The residual mercury contents in the biological samples revealed that bio-accumulation by bottom-dwelling organisms are higher than the pelagic components.

Determination of dissolved oxygen in water with leukoberbelin-blue I. A quick Winkler method. [Translation from: Z.analyt.Chem. 262 97-99, 1972.]

The reaction of Mn(II) with water-dissolved oxygen, to a higher manganese hydroxide in an alkaline medium, as with the longstanding classic Winkler method, is the first step in the method described here. The assumption for faultless results by the conventional and modified Winkler method is clean water, which contains no organic substances by Mn(III) or Mn(IV). In many cases, however, eg. in river and lake-water tests, it can be seen with the naked eye that after some time the originally brown-coloured precipitate of manganese hydroxide becomes more and more colourless. Oxygen content was analysed in the water samples and evaluated by raising the amount of the leuko-base and giving the corresponding dilution of the colouring matter solution formed still higher oxygen contents can be measured.

Application of algal bioassays in the determination of eutrophic power of waste water (”Conclusions” only) [Translation from: 1g.Sanita pubbl. 31 257-267, 1975]

The best evidence for establishing the level of eutrophy of a water-body is its algal production which makes it possible to identify the type and the intensity of the eutrophication according to the kind and number of algal species present: when the number of algae exceeds half a million per litre then one speaks o an ”algal bloom”. The scope of the present research aims to verify if the alga Selenastrum capricornutum can be used as a test alga under our culture conditions and to determine the eutrophic level of the secondary effluent of a modern plant for the treatment of domestic discharge and to investigate the eventual ”limiting factors”. Finally this paper aims to study the effect on the secondary effluent of tertiary treatment carried out artificially in the laboratory.

Determination of water quality in lakes by biological indices

Some problems of evaluation of water quality by biological indices which can be applied in the practice of ecological monitoring on water bodies are considered in this report. Taking into account, that ecological monitoring is the most urgent for large lakes, situated in civilised (urbanised) and (or) agrarian landscapes the corresponding problems will be considered mainly in conformity with large deep lakes of temperate latitudes. The aim is a general evaluation of some of the methods from the point of view of their possible application for monitoring on large water bodies.

Determination of ubiquinone and tocopherol in heart, liver and muscle tissues of fresh water fish, Rohu (Labeo rohita, Hamilton)

The liver, heart and muscle tissues of Rohu, (Labeo rohita, Hamilton) were examined for their ubiquinone (UQ) and tocopherol contents. These three tissues contained respectively 11.60, 3.94 and 0.19 mg of ubiquinone and 10.16, 5.32 and 3.58 mg of tocopherol per 100 g. The 4% (V/V) of diethyl ether (EE) in light petroleum ether (PE) fractions of all three tissues on paper chromatographic separation gave spots having the same Rf value as standard ubiquinone-50 (UQ 10). Both the 4% and 6% (V/V) diethyl ether in light petroleum ether fraction of liver, heart and muscle tissues gave a single spot with the same Rf value as α – tocopherol.

Determination of optimum stocking density of Macrobrachium rosenbergii larvae using multiple feed in a commercial hatchery at Cox’s Bazar, Bangladesh

Experimental stocking density of Macrobrachium rosenbergii in larval rearing was conducted in A.G. Aqua Hatchery, Chakaria, Bangladesh to study the effect of different stocking densities on growth, survival rate and diseases stress under hatchery condition. The research work was conducted using six cemented rectangular tanks having 3m3 capacity (1.5mX2mX1m) each. Stocking density were maintained in three experimental setup as 200, 150 and 100ind/L of the T1, T2 and T3 respectively with one replicate each. The larvae were fed with Artemia nauplii, Custard, Maxima and brine shrimp flakes. Water quality was maintained by exchanging 20-30% (12ppt saline water) daily. During the study period, temperature, pH, DO, salinity, nitrite-nitrogen, ammonia and alkalinity were maintained from 28.5-31.5ºC, 7.5-7.8, 5.8-5.9mg/L, 12-13ppt, 0.14-0.2 mg/L, 0.22-0.3mg/L, and 140-160mg/L respectively. The growth rates of larvae at 11th stage were recorded in terms of body length 0.115, 0.136, and 0.169 mm/day whereas body weight were observed 0.000115, 0.000180, and 0.000240g/day. The survival rate of larvae were found 21.8%, 30.4% and 51.3% in treatments T1, T2 and T3 respectively. PL was obtained as 43, 45, and 51PL/L and days required of 41, 38 and 34 days in stocking density of 200, 150, and 100ind/L respectively. It was found that the minimum of 34 days was required to attain the PL (12th stage) using the stocking density of 100 individuals/L. Cannibalism, Zoothamnium, Exuvia Entrapment Disease (EED), and Bacterial Necrosis (BN) were found to be the threat to the commercial hatchery operation that might responsible for potential larval damages which can be reduced by lowering the stocking densities in larval rearing tank that also increased the survival and growth rate.

On the methods of determining size/weight characteristics of food organisms of fish. (Determination of the length of Copepoda in larval stages by egg-laying females of the free living freshwater Copepoda). [Translation from: Voprosy Ikhtiologii 14, 182-194, 1960. ]

As is known, copepods play an important role in the nutrition of fish. Therefore with a view to facilitating research on the study of the quantitative side of feeding, there have recently appeared a considerable number of papers devoted to the development of methods for determining the wet. weight of these crustaceans. For the further facilitating of research in the nutrition of fish it would be of great interest to clarify the problem, is there not some kind of rule in the growth of the crustaceans during metamorphosis, and if there is such a rule is it not possible, to determine the length of the larvae at each stage, not by measuring them, but by using the formulae derived on the basis of these rules. This article examines the growth curves of different species of freshwater Copepoda, obtained on the basis of experimental observations in cultures or by way of measurement of mass material at all stages of development in samples from water-bodies. The authors study in particular the ratio of the mean diameter of the eggs to the mean length of the egg-bearing females.

For the determination of iron (II) and total iron with 2,2'-dipyridyl in mineral waters. Reduction of iron (III) with ascorbic acid [Translation from: Zeitschrift fur Analytische Chemie 209 340-341, 1965]

The determination of bi- and trivalent iron in proximity, in mineral waters has gained in significance, on biological and technical grounds. This short paper describes the procedure of the determination of bivalent iron and total iron in a water sample.