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Municipal Wastewater Management
Published in Mary K. Theodore, Louis Theodore, Introduction to Environmental Management, 2021
Mary K. Theodore, Louis Theodore
The chemical characteristics that are of interest are toxic metals (cadmium, chromium, lead, and mercury) and nutrients (nitrogen, phosphorus, and carbon) being discharged into the water. Toxic metals and/or chemical compounds can cause large fish kills or can lead to the consumption of contaminated fish by humans and other mammals. The discharge of nutrients into a water body at first seems to be beneficial to the local ecology due to the production of algae and its supplement to the food chain. However, too many nutrients will produce gross masses of algae. Eventually the algae will die off and sink to the bottom of the water column forming a layer of biomass. As the algae decays (use of oxygen), the deficit of dissolved oxygen will suffocate the bottom-dwelling fish and shellfish.
Human Interventions on Water Ecosystem and Implications for Fisheries Resources in Bangladesh
Published in E. R. N. Gunawardena, Brij Gopal, Hemesiri Kotagama, Ecosystems and Integrated Water Resources Management in South Asia, 2020
M. Monirul Qader Mirza, Mokhlesur Rahman, Anisul Islam
Pollution in Bangladesh’s rivers, canals, wetlands and ponds caused by industrial and urban effluents has reached alarming levels. The most polluted rivers are the Buriganga, Sitalakhya, Turag, Karnafuli and Rupsha. Fish population is affected by pollution at a time when demand for fish is increasing at a faster rate than before. Water pollution occurs from both ‘point’ and ‘non-point’ sources. Point source pollution occurs by the discharge of wastewater from industries such as textiles, tanneries, pulp and paper mills, fertiliser, industrial chemical production and refineries (WARPO 2000; UNEP 2002). A complex mixture of hazardous chemicals, both organic and inorganic, is discharged into the water bodies usually without treatment. Recent statistics of the polluting industries in Bangladesh is not available. However, JICA (1999) reported the existence of 1,176 polluting industries which were categorised into nine major types: chemical including pharmaceutical, paper and pulp, sugar, food and tobacco, leather, industrial dyes, petroleum, metals and power generation. Most of the older industries are not equipped with treatment facilities. Their effluents generally have high Biological Oxygen Demand (BOD), very high Chemical Oxygen Demand (COD) and contain high levels of sodium sulphate, ethanoic acid, reactive dyes and detergents (Chadwick and Clemett 2003). JICA (1999) reported that 71,200 tons of BOD is discharged annually in Bangladesh of which the highest 61 tons/day comes from the fish and food processing industries. Fish kills often occur in polluted water bodies.
The Ecological Significance to Fisheries of Bottomland Hardwood Systems: Values, Detrimental Impacts, and Assessment: The Report of the Fisheries Workgroup
Published in James G. Gosselink, Lyndon C. Lee, Thomas A. Muir, Ecological Processes and Cumulative Impacts, 2020
H. Dale Hall, Victor W. Lambou, Paul Adamus, James Brown, C. Fred Bryan, Ellis Clairain, Fred Dunham, Gerry Horak, Joseph Jacob, Richard Johnson, Albert Korgi, William Kruczynski, Edward Smith
Industrial sites such as paper mills, battery factories, sewage treatment plants, and toxic waste disposal areas can often discharge materials that are harmful to finfish and shellfish. Information on locations of such sources and water-quality standards for various pollutants can be obtained from the state and federal regulatory agencies. Licensing information on particular chemicals can also provide data on the potential effects on aquatic life. Direct evidence of potential problems may be obtained from observations of fish kills and studies of benthic populations. If any of these sources indicate lethal levels of pollutants, the value of the bottomland hardwood site is likely to be low for finfish and shellfish. If no evidence of lethal concentrations is found, the assessment should proceed, but with the recognition that sublethal concentrations of many pollutants can still affect growth and development of aquatic organisms.
Dynamics of runoff quality associated with an urban park and WSUD treatment train in a tropical climate
Published in Environmental Technology, 2023
K. N. Irvine, Huu Loc Ho, Lloyd H. C. Chua
DO is needed for a healthy and diverse aquatic ecosystem, although different fish species have different dissolved oxygen requirements. The mean DO level entering the pond is slightly greater than the level leaving, which is not unexpected due to the turbulence related to inflowing storm water and hydraulic residence time of the pond (Table 5). Singapore does not have guidelines for DO levels in waterbodies, although Thailand uses a guideline of 4 mg/L for its Class 3 waters (medium clean, can be used for consumption after ordinary treatment and for agriculture) and 2 mg/L for its Class 4 waters (fairly clean, can be used for consumption, but requires special treatment process and for industry) [90]. In New York State, the guidelines for Class A, B, and C, non-trout waters, are such that the minimum daily average shall not be less than 5.0 mg/L, and at no time shall the DO concentration be less than 4.0 mg/ L (e.g. [65]). Various ornamental and native fish species have been observed in the Sakura Pond and low DO levels reportedly have resulted in fish kills along the Kallang River section of Bishan Park, Singapore (https://www.straitstimes.com/singapore/hundreds-of-dead-fish-found-in-bishan-ang-mo-kio-park-river; accessed 12 April 2021), so visual monitoring of fish health would be prudent.
Hypolimnetic oxygenation 6. Improvement in fisheries, hydropower, and drought management with costs of installation and operation in Camanche Reservoir, California, United States
Published in Lake and Reservoir Management, 2022
Alex J. Horne, William K. Faisst
The water management community uses several methods to reduce toxicants, nutrients, turbidity, and eutrophication and thus to prevent fish kills in reservoirs and their tailwaters. This article describes one cost-efficient solution to prevent harm to fisheries downstream of Camanche Reservoir. Kills had occurred intermittently from the time of reservoir construction in 1963–1964 until 1993, when East Bay Municipal Utility District (EBMUD), Oakland, California, the owner and operator of the reservoir, installed a submerged downflow contact oxygenation device (Speece cone) as a hypolimnetic oxygenation system (HOS) in the reservoir near the dam (Fig. 1a). Effects on fish, oxygen dynamics, nutrients and eutrophication, turbidity, and heavy metals are presented in 5 accompanying papers (Horne 2019a, 2019b, Horne and Jung 2022, Horne et al. 2019a, 2019b).
Controlling water hyacinth (Eichhornia crassipes (Mart.) Solms): a proposed framework for preventative management
Published in Inland Waters, 2022
Linda May, Anne-Jo Dobel, Collins Ongore
The adverse environmental impacts of WH invasion on a waterbody include a decline in water quality, higher water losses due to increased evapotranspiration rates (Lallana et al. 1987), greater siltation rates, and an overall decline in freshwater biodiversity. Areas of a waterbody with high WH infestations have significantly lower water quality than those without WH in terms of their colour, turbidity, and dissolved oxygen concentrations (Mailu 2001). The associated drop in oxygen levels can be sufficient to cause fish kills (Adan 2010), which can decimate fisheries and cause a more general loss of biodiversity. The loading of large quantities of plant organic matter to the lake bed from sunken WH biomass and other macrophyte detritus causes changes in water chemistry, an emerging environmental concern for the Winam Gulf of Lake Victoria in recent years. The Winam Gulf is especially prone to high levels of WH infestation because it is shallow, relatively sheltered, and receives high levels of nutrients from its catchment (Mitchell 1976).