Determination of the activity of nitrifying bacteria in surface waters by a modified BOD-test. [Translation from: Zentbl.Bakt.Parasitkde 156(1) 414-421, 1972. ]

A modified method of the Biochemical oxygen demand (BOD)test was applied in order to find out the seasonal changing activity of the nitrifying bacteria in surface waters. Samples were taken from the River Elbe near Teufelsbrueck.

An appraisal of the current status of the fisheries of Eleiyele Reservoir by its fisheries cooperatives

In a study undertaken to evaluate the status of the fisheries of Eleiyele Reservoir (Nigeria) between 1995 and 1997, thermal stratification was observed to breakdown between December and March. Of the physico-chemical variables, transparency was positively correlated (p<0.05) with primary productivity, conductivity and dissolved oxygen concentration. Primary productivity ranged between 0.38mgC/m super(2)/d and 3.OmgC/ m super(2)/d, being lowest in April. BOD values ranged between 1.3mg-2.2mgO/l indicative of clean unpolluted water. Nine fish species belonging to the families Cichlidae, Centropomidae and Mochokidae were identified. Cichlids were the most abundant with Hemichromis species being predominant. Fishing was only carried out in the reservoir during the dry season months of November to April. Fish landing data for the reservoir, obtained from the Fisheries Division of the Ministry of Agriculture and Natural resources, Oyo State, in conjunction with comparative data from the Cooperative fishermen was low. It demonstrated a decreasing trend from January to April and during the period between 1985 and 1996, when compared with data collected in 1985 and 1986 from a previous similar study. Reasons for the low fish yield from the reservoir are discussed and compared with other Nigerian reservoirs

Environmental impact assessment of agrochemicals for fish production - a review paper

The environmental impact of agro-chemicals for fish production was extensively reviewed. The positive contribution of agro- chemicals and the devastating effect on aquaculture was x-rayed to alert users to this obvious environmental problem. Lime and fertilizers are commonly used in fish farming to increase pH of pond soil and water and to increase alkalinity and hardness, reduce humic acid content and to initiate primary and secondary productivity. Devastating effect of lime on environment is likely to be minimal. In the case of fertilizers, over utilization of this agro-chemical could impair water quality as phytoplankton bloom become excessive which consequently raises BOD. The use of Therapeutants in aquaculture was discovered to be more popular in Europe and North America than in the tropics (Africa). Commonly used therapeutants include antibiotics and antimicrobials. For fish pathology chemicals like formalin, potassium permanganate, Dipterex and malachite green are widely in use. Effluent from farms where these chemicals are commonly in use can distort the aquatic ecosystem. The changes in water quality, aquatic community structure and productivity caused by intensive aquaculture are typical of the impacts of pollution from a wide variety of sources like sewage, agricultural run-off and effluent discharges from industry

A review of diseases associated with cage culture systems: diagnosis and control in smale scale fish farming

Fish cage culture is a rapid aquacultural practice of producing fish with more yield compared to traditional pond culture. Several species cultured by this method include Cyprinus carpio, Orechromis niloticus, Sarotherodon galilaeus, Tilapia zilli, Clarias lazera, C. gariepinus, Heterobranchus bidorsalis, Citharinus citharus, Distochodus rostratus and Alestes dentes. However, the culture of fish in cages has some problems that are due to mechanical defects of the cage or diseases due to infection. The mechanical problems which may lead to clogged net, toxicity and easy access by predators depend on defects associated with various types of nets which include fold sieve cloth net, wire net, polypropylene net, nylon, galvanized and welded net. The diseases problems are of two types namely introduced diseases due to parasites. The introduced parasites include Crustaseans, Ergasilus sp. Argulus africana, and Lamprolegna sp, Helminth, Diplostomulum tregnna: Protozoan, Trichodina sp, Myxosoma sp, Myxobolus sp. the second disease problems are inherent diseases aggravated by the very rich nutrient environment in cages for rapid bacterial, saprophytic fungi, and phytoplanktonic bloom resulting in clogging of net, stagnation of water and low biological oxygen demand (BOD). The consequence is fish kill, prevalence of gill rot and dropsy conditions. Recommendations on routine cage hygiene, diagnosis and control procedures to reduce fish mortality are highlighted

Water quality monitoring in the Mersey

This is the Water Quality Monitoring in the Mersey Estuary report produced by the Environment Agency in 2001. This report focuses on the Water Quality Monitoring Programme held in the Mersey Estuary. Since the mid-1960s water samples have been collected at approximately monthly intervals along the length of the estuary between Warrington and New Brighton and in later years further off-shore. This data-set provides an invaluable resource to determine how the very large capital spending of recent years has resulted in the dramatic improvements in water quality that we are now able to record. Initially, the interest was focused on parameters such as dissolved oxygen, BOD, nutrients and suspended solids. Over the last decades, as analytical methods have improved, toxic metals and persistent organic compounds have been included in the routine monitoring programme at a limited number of sites. Moreover, with the introduction of the European Water Framework Directive monitoring programmes it was an opportune time to review the Mersey monitoring strategy. This revised monitoring programme required data from several other components (water, sediments, flora, fauna, fish and birds. This report also contains information about Routine monthly surveys, Special surveys, Chloralkali Directive, UKNMP, British Geological Survey, EDMAR and NERC Environmental Diagnostics Thematic Programme.

Kent estuary survey 18th August 1981

This is the Kent estuary survey 18th July 1981 produced by the North West Water Authority in 1981. The report focuses on a tidal cycle survey carried out on the Kent estuary on the 18th August, 1981. The chemical water quality at Arnside Pier and at New Barns was, on the whole, acceptable. However, samples taken downstream of the outfall at low water for total coliforms and E. coli were all above the EEC mandatory level whilst those for faecal streptococci were all above the guideline value. This document shows chemical and bacteriological data analysed at Kent estuary such chloride, dissolved oxygen, BOD, ammonia, nitrate, phosphate, total coliforms, E. coli and Faecal streptococci.

The Kent estuary 1992 surveys. Summary of results

This is the Kent estuary 1992 surveys: Summary of results produced by the National Rivers Authority in 1993. The report summarises routine and baseline water quality surveys carried out on the Kent estuary during 1992. Baseline surveys are designed to respond to regional, national, and European requirements. During 1992 baseline surveys were carried out in June and December. Unfortunately, in June, samples could only be taken from stations 3, 7 and 8. For ease of interpretation the results have been presented in graph form, including the maximum and minimum parameter concentration and the appropriate Environmental Quality Standards (EQS). The parameters measured in this survey were physical parameters (temperature, BOD, dissolved oxygen, Ph, salinity, conductivity); nutrients (ammonia, phosphate, and nitrate); metals (Mercury, Nickel, Arsenic, Cadmium, Chromium, Cooper, Boron, and Zinc) and organic compounds.

Mahim Bay: a polluted environment of Bombay

Distribution of the marine life in relation to the extent of pollution at and outside Mahim Bay was studied. A poor marine fauna at stations A and B was associated with a relatively high intensity of pollution accompanied by high BOD and nutrients and low DO levels. A distinct deterioration in the marine life and water quality along the northern part of the bay as compared to the southern part was evident. An increasing trend in the marine fauna with decreasing intensity of pollution from inside to outside the bay was noticed.

On the water quality of selected environments along Bombay coast

Water quality of three stations representing polluted (Sts. B & S) and relatively unpolluted (St. M) areas along the coast of Bombay was studied during Mar 1981 to May 1982. Stations B & S were characterized by relatively wider fluctuations in salinity, low range of dissolved oxygen and higher BOD, phosphate and nitrate levels. At St. M higher range of dissolved oxygen coupled with low values of BOD and nutrients suggest the prevailing good water quality. The deteriorating water quality of the polluted station probably lead to retarded growth of Saccostrea cucullata and Cerithium rubus living in the shallow intertidal region.

Studies on the status of pollution in certain estuarine areas in Kakinada

The BOD levels and saprotrophication of 2 stations in an estuarine habitat at Kakinada India, was studied during one full tidal cycle. Both the stations were found to be heavily polluted by sewage with BOD values ranging between 10.8 and 12.8 ppm at the commercial canal (station 1) and between 4.8 and 8.8 ppm at the mangrove creek (station 2). Tides did not seem to have much influence on the dilution of the pollutants. Based on planktonic indicator species observed and saprobity index which worked out to be 2.75, both the sampling areas are considered as heavily polluted alpha-mesosaprobic zones.

Fish and shell fish fauna of the retting and nonretting zones of the Kadinamkulam kayal, Kerala

Retting of coconut husk is one of the major problems of pollution in the estuaries (kayals) of Kerala. Retting activity has resulted in the mass destruction of the flora and fauna and has converted sizeable sections of the kayal into virtual cesspools of foul smelling stagnant waters. Levels of hydrogen sulphide, phosphate and BOD, increased while dissolved oxygen and fish and shellfish fauna decreased in the ambient waters. In the Kadinamkulam kayal a total of 37 species of fishes belonging to 26 families, 5 species of prawn and 2 species each of crabs and molluscs were recorded from the no retting zone, whereas only 20 species of fish in dead condition were collected from the rating zone. Prawns, crabs and molluscs were absent at the vetting zone. Majority of the fish fauna in the kayal were marine forms.

Investigation on water quality in the Ashulia beel, Dhaka

The study was conducted to get an idea about the water quality of the Ashulia beel, and its temporal change over wet and dry seasons due to change of the physicochemical parameters. The water body has become a dumping ground of all kinds of solid, liquid and chemical wastes of bank side population and industries. Encroachment and illegal dredging has become a serious threat for the sound environment of the beel. The water parameters of pH 7.1-7.8 and alkalinity 30-63 mg/l in wet, and pH 7.1-8.4 and alkalinity 90-115 mg/l in dry season, respectively, which were within the standard range of DoE investigation. During wet season, EC 130-310 mg/l, TDS 80-132 mg/l, DO 1.1-2.1 mg/l and BOD -4.4-1.6 mg/l were measured. In dry season, EC 341-442 mg/l, TDS 207-276 mg/l, DO 0.5-2.0 mg/l and BOD 1.0-3.0 mg/l were measured. The comparative analysis showed that most of the water quality parameters of the Ashulia beel were suitable for aquatic organisms including fishes while the DO contents were much lower than the desirable level which may not be suitable for fishes.

Ecosystem structure of Gomishan Wetland

Gomishan Wetland is situated in the extreme southern part of the eastern coast of Caspian Sea. It is connected to the Caspian Sea, so its hydrological features are directly generated from the sea. The whole wetland area (which also consists of the northern part of the wetland that is situated in Turkmenistan republic) is calculated with the aid of the Satellite Images for the years of 1977, 1987 and 1998 respectively 5070, 16320 and 29520 hectares. To have better ideas about food chains in the aquatic ecosystem, five permanent stations was appointed in different parts of the wetland. During one year field study, at the beginning of each month, physical, chemical and biological characteristics of the water and the sediment was surveyed and different specimens were gathered, fixed and took to the laboratories for the relevant analyses. The factors measured in water samples were mainly consist of turbidity, pH, EC, DO, BOD, PO4, NO3, alkalinity, Cl and hardness . The factors measured from sediment samples were the percentage of Sand, Very Fine Sand, Silt, Clay, K, P, N, and Organic Carbon. Biological examinations of the water has been consist of planktonic sample collections, determination, counting and analysis of both phyto and zoo planktons of the wetland. For example the zooplanktons of the Gomishan Wetland are determined in 15 groups, belonging to 5 phyla. The seasonal changes are recognized considerable. The least density of the zooplanktons is occurred in February. The density of most of the groups is seen from the beginning of the summer until the mid autumn. The annual mean density for any 15-zooplankton groups and also the minimum and maximum density with %95 confidences, for each of them, is calculated for the environment of all of the stations and also for the whole wetland. The spatial distribution of the individuals within the population of each of the groups is introduced, according to regular or contagious or random distribution. Diversity indices are calculated for the zooplanktons living in the environment of the stations. Comparison of the wetland, with the southeastern Caspian Sea, from the point of view of zooplankton density and diversity is also obtained. Benthos invertebrates in each station from sediment samples were also extracted. The specimens were colored by Rose Bengal solvent and then were determinate and counted, in separate groups of macro and meio benthos. Among the macro benthos, the highest density was seen in the species of Fyrgula caspia. After that, more density was seen respectively in Apra ovata, Cerastoderma sp., Balanus sp., Nerds divesicolarr, lifytilaster lineatus and Dreissena sp. Among the meio benthos, the most density was seen in Foraminifera and then respectively in Ostracoda, Nernatoda and Bivalve larvae. The indices of diversity and distribution are also calculated. As the birds in this lagoon are of prime importance, all mid winter waterfowl censuses available from recent 13 years are gathered and analysis. Also a whole year (12 times, each at the beginning of one month) waterfowl census was undertaken, throughout the wetland. According to this study, the Eastern Ecosystem of the wetland, is supporting the most population (%75) of the waterfowls, the Middle Open Water Ecosystem and the Western Reed bed Ecosystem, are supporting respectively %14 and %11 of the population. Four of the species are found in the global threatened red list, and the wintering population of the 20 species of the site, in some years, are observed more than %I of the global populations. The Waterfowl Species Diversity and Similarity Indices are given also.