International Postgraduate Research Conference (IPRC)

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Author: search.filters.author.Premaratne, W.A.P.J.Subject: search.filters.subject.water pollution

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    Analysis of Water and Sediment in Attanagalu Oya in Sri Lanka: Pollution Levels and Effects
    (In: Proceedings of the International Postgraduate Research Conference 2017 (IPRC – 2017), Faculty of Graduate Studies, University of Kelaniya, Sri Lanka., 2017) Premaratne, W.A.P.J.; Perera, H.S.M.
    The Attanagalu Oya plays a major role in national water supply since it contains four major national water supply and drainage board intakes. This study intends to investigate the water quality variation and pollution levelin Attanagalu Oya in Gampaha municipal council area.Sampling was conducted for a period of six months from November 2016 to April 2017 at nine locations situated between 7° 05' 33.8" to 7° 05' 53.1’’N latitude and 79° 58' 15.6"to 79° 59' 32.5"E longitude along the main river. Both water and sediment samples in the river were collected and tested for physical and chemical parameters. Electrical conductivity (EC), pH, titratable acidity, total hardness, chemical oxygen demand (COD), and metal ions content (Fe, Pb, Cd, Ni, Mn, Cu) were analyzed in water samples. EC, pH, organic matter content and soil texture were analyzed in sediment samples. Experimental results were ascertained to find out the quality and pollution level of water and sediment by comparing with the standards levels given by the Central Environmental Authority (CEA) in Sri Lanka and World Health Organization (WHO) guidelines. According to the experimental results, average pH values of water in the river was from 7.1 to 7.6 and did not exceed the proposed ambient water quality standards for fish and aquatic life. EC values ranged from 81.9 to 91.7 μS/cm and conductivity shows a drastic increment due to dry season. Titratable acidity, total hardness and metal ions content in water samples were not in the limits of CEA and WHO standards for drinking water parameters. COD values of water samples exceeded the maximum CEA standards during the sampling period. Sediment analysis indicated that physical and chemical parameters are not in the limits of CEA standards. Therefore, this study shows that the river is polluted and the effects being significant in the urban areas.
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    Assessment of Water Quality Status and Pollution Levels in Maduru Oya Reservoir in Sri Lanka
    (Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2016) Kasthuriarachchi, T.D.W.; Wickramaarachchi, W.D.N.; Premaratne, W.A.P.J.
    MaduruOya reservoir was constructed in 1983 under the Accelerated Mahaweli Program. The dam is located in North Central province and the reservoir extends to Eastern province and Uva provinces (between 7º 32' 42" to 7º 39' 57" North latitude and 81º 11' 35" to 81º 12' 21" East longitude). It is reported that high amount of nutrients and other chemical residues accumulate in water of the reservoir due to heavy use of agrochemicals in the catchment area. Fifteen locations were selected for sub-surface water sampling and analysis from February to July in 2016. Temperature, pH, Dissolved Oxygen (DO), Electrical Conductivity (EC) and Turbidity were measured in-situ. Ammonical nitrogen, nitrate nitrogen, nitrite nitrogen, dissolved phosphate, and other chemical parameters such as alkalinity and hardness were also assessed. Water temperature of the reservoir varied from 29.7 ͦ C to 36 ͦ C while pH value was from 6.8 to 9.5. DO value was from 3.3 ppm to 9.4 ppm. EC varied from 94 μS cm-1 to 200 μS cm-1 and turbidity of water fluctuated from 0.96 NTU to 49.4 NTU. Ammonical nitrogen varied from 0.001 ppm to 0.652 ppm. Nitrite Nitrogen was from 0.001 ppm to 0.905 ppm and Nitrate Nitrogen was detected from 0.001 ppm to 1.131 ppm. The highest phosphate concentration was detected as 0.468 ppm near the dam site of the reservoir in July. Total hardness was from 21ppm to 68 ppm and alkalinity varied from 15 ppm to 190 ppm. The highest pH was recorded in June near the dam site of the reservoir and exceed the WHO standards for drinking water. The maximum nitrate and nitrite concentrations were recorded in June at the middle of reservoir and maximum ammoniacal nitrogen was also recorded in June and it was at the dam site. High accumulation of nutrients can lead to eutrophication in the reservoir and it causes the spreading of toxin producing algal species such as Microcystis affecting the ecosystem health and human livelihood.