Environmental Management
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Item Health implications related to mismanagement of domestic and municipal wastewater in Sri Lanka.(Sage Publishers, India., 2011) Najim, M.M.M.; Rajapakshe, I.H.TRADITIONALLY IN SRI LANKAN villages domestic wastewater, especially grey-water generated from kitchens and bathrooms of a household, fl ows along open unlined wastewater drains and is collected in a garden pool known as kohila wala or vegetation pool. This pool is a kind of traditionally constructed wetland. Main vegetation type cultivated in the wetland is kohila (Lasia spinosa) which is used as a leafy and stem vegetable. Medicinal and other important plants are also grown along the drains that utilise the wastewater and its nutrients. This system of grey-water disposal and utilisation was always kept separate from the black-water disposal system as the latter is disposed to individual cesspits located in home gardens. In the traditional sys tem, natural capacity to treat wastewater without any harmful effects to groundwater was possible due to low population density and land availability. With the population expansion in urban centres, the land value increased and land area available for the traditional wastewater treatment process shrank.Item Adapting Sri Lanka to Climate Change: Approaches to Water Modelling in the Upper Mahaweli Catchment Area(Climate Change Research at Universities. Springer, Cham, 2017) Gunawardena, M.P.; Najim, M.M.M.Water flow and water quality changes in surface water bodies due to climate change is a major problem worldwide, typically in river eco-systems. To address these issues, proper monitoring of river flow variations and water quality is necessary, but daily monitoring and data collection is greatly time consuming and costly. Therefore, a study was done with the objectives to calibrate and validate the HEC-HMS 3.5 and HEC-RAS 4.1.0 models to simulate flow variation and water quality variations respectively in Nillambe Oya, Sri Lanka. The development of such models are a significant requirement in the present scientific world to predict river flow and water quality variations as an adaptation for the climate change. The HEC-HMS 3.5 model was used to generate flow which is needed for HEC-RAS 4.1.0. Daily flow data for five years (from October 1991 to September 1996) were used to calibrate the HEC-HMS 3.5 model and another set of daily flow data for five years (from October 1994 to September 1999) were used to validate the model. HEC-RAS 4.1.0 model was calibrated using water quality data collected and analyzed in five days. The validity of the calibrated model was evaluated using water quality data collected in the other four days. The calibrated and validated HEC-HMS 3.5 model reliably predicted the flow in Nillambe Oya. The calibrated and validated HEC-RAS 4.1.0 model simulated Dissolved Oxygen (DO), Biological Oxygen Demand (BOD) and Nitrate Nitrogen (NO3-N) splendidly. Orthophosphates was also predicted reliably by the model, but the simulation of organic Phosphorus was not that sensible.Item Seasonal Variation of Rainfall at Attanagalu Oya Basin(Geo-Informatics Society of Sri Lanka, Peradeniya. Sri Lanka., 2012) Waniganethti, D.; Najim, M.M.M.; Halwatura, DItem Trends in Dry and Wet Events of Rainfall in Aththanagalu Oya Basin(Geo-Informatics Society of Sri Lanka, Peradeniya. Sri Lanka, 2014) Udayanga, N.W.B.A.L.; Najim, M.M.M.Item Environmental Flow Assessment–An Analysis(Journal of Environmental Professionals Sri Lanka,, 2014) Halwatura, D.; Najim, M.M.MNatural flow of a river is recognized as vital to sustaining riverine ecosystems. The biotic composition, structure and function of aquatic ecosystems depend largely on the hydrologic regimes; however flows of the world’s rivers are increasingly being modified through impoundments. Therefore calculation of the optimum flows for a healthier river is essential but there is no simple figure that can be given for the environmental flow requirements of rivers. Environmental flows refer to water for ecosystems. Ecosystems, however, provide a wide range of valuable services to people. Concept of the environmental flow was initiated not only to discover the river health and to manipulate river flow regimes, but also to get the maximum harvest from free flowing waters. Hence, providing for environmental flows is not exclusively a matter of sustaining ecosystems but also a matter of supporting human well being. As demand for freshwater continues to rise and ways are sought to improve water productivity, decision-making bodies at local, basin and national levels require accurate information on the role of river flows in sustaining a wide range of environmental benefits. For that reason assessment of environmental flows may contribute to setting management rules and monitoring their impact on river health.Item Quantitative analysis of water quality and heavy metals in water, sediments and tissues of Grey Mullet (Mugil cephalus) from the Negombo estuary(Colombo Journal of Multi-Disciplinary Research, 2015) Mendis, B.R.C.; Najim, M.M.M.; Kithsiri, H.M.PThe objectives of this study were to assess the levels of water quality and heavy metals of the water, sediments and fish tissues in the Negombo estuaries. For this study, samples were collected from sixteen sampling locations during the one year study period from January to December 2014. The results revealed that the average concentrations of ammonia, nitrate, pH, electrical conductivity, total suspended solids of 0.215±0.4mg/l, 1.08±0.98mg/l, 7.8±0.28, 29.6±1.56ms/cm, 29.2±0.35mg/l, levels were below the maximum permissible limits. Biochemical Oxygen Demand 24.8±1.3mg/l and Chemical Oxygen Demand 469.0±36.5mg/l levels were much higher than the permissible threshold limits of industrial wastewater quality standards for CEA,(2001) Sri Lanka. The results indicated that the concentrations (ppm) of heavy metals in water were Pb,0.01±0.0003; Cd,0.015±0.003; Hg,0.013±0.001; Zn,0.695±0.06; Cu,0.03±0.02; Cr,0.055±0.004 and Fe,0.485±0.04 respectively. The sediments concentrations (mg/kg) were Pb,7.95±0.95; Cd,1.06±0.23; Hg,0.001±0.52; Cu,0.042±3.2; Cr,14.30±1.5, Zn,154.25±3.2 and Fe,78.6±101.2 respectively. The concentrations (mg/kg) of metals in the fish tissues were Pb,0.57±0.48; Cd,1.045±0.28; Hg,0.05±0.046; Zn,119.2±111.3; Cu,4.60±1.64; Cr,5.22±2.49 and Fe,32.8±59.3 respectively. The highest concentrations of pollution status were recorded in the Northern region of the estuary.Item Bioaccumulation of Heavy Metals in the Selected Commercially Important Edible Fish Species Gray Mullet (Mugil cephalus) from Negombo Estuary.(Journal of Environmental Professionals Sri Lanka,, 2015) Mendis, B.R.C.; Najim, M.M.M.; Kithsiri, H.M.P.; Azmy, S.A.M.Consumption of fish contaminated with non essential heavy metals such as Pb, Hg and Cd metals which exceed the required limits pose a risk to human health. Bioaccumulations of heavy metals in fish depend on several factors such as increased levels of industrial pollution and domestic solid waste dumping in the estuary. Based on the pollution inputs into the estuary, it is considered that different localities within the estuary are polluted at different rates. The objectives of this study were to determine the non essential heavy metals concentration in fish tissues and assess the seasonal variations in the ecosystem. For this study, fish tissue samples were collected from nine sampling locations along the North (n =3), South (n=2), West (n=2), and East (n=2) parts of the estuary for a period of one year from January to December 2014. Fish tissue heavy metals levels were analyzed employing standard methods. Results revealed that the average concentrations (mg/kg) varied from Pb 0 to 0.15 ± 0.06, Cd 0.35 ± 0.16 to 1.04 ± 0.28 and Hg 0.0005 ± 0.0004 to 0.05 ± 0.046 mg/kg respectively. The detected levels were below the maximum permissible limits for hazardous substances in fish and fishery products for recommendation of FAO. The detected lead, mercury and cadmium contents in fish tissue were below the standard limits defined for each element < 0.5 mg/kg < 0.05 mg/kg and < 0.05 mg/kg respectively. Significant differences (P< 0.05) were observed for Pb and Hg depending on fish tissues. The levels of Pb and Hg metals in muscle tissue were lower than the standard limit for FAO. The value obtained on Cd 1.04 ± 0.28 mg/kg concentration was much higher than the permissible threshold limit observed in the north, south, east and west regions. The most prominent increases in Pb and Cd metal concentrations in fish tissue were found during the October, November and December study of 2014, which corresponded to peak periods from October, November and December which apparently coincided with the second inter monsoon of the island respectively.Item Heavy Metals Levels in Water, Sediments and Edible Fish (Mugil cephalus) Tissues of Negombo Estuary, Sri Lanka(NARA Journal, Volume 44,, 2015) Mendis, B.R.C.; Najim, M.M.M.; Kithsiri, H.M.P; Azmy, S.A.M.Item Assessing toxicity of two industrial zone effluents reaching Kelani River,Sri Lanka(Journal of national science foundation Sri Lanka, 2018) Hemachandral, C.K.; Pathiratne, A.Evaluation of the effcaey of waste treatment technologies of industnal waste is a major challenge for sustainable industrial development world-wide. Hence, new strategies are needed to assess interactive toxic effects of all substances present in the treated waste. This study assessed potential toxic hazards of treated effluents discharged from common wastewater treatment plants of two mclustrlal zones located in the Kelani River basin using Allium cepa (common onion) test system. The results showed that the final effluents of both industrial zones under undiluted and diluted (1 IS v/v) conditions mduced cytotoxrcity on all occasions, with evidence of significant (p < 0.05) mlto-depression In the root meristem and retardation of root growth in A. cepa. Genotoxlc hazard of the effuents was evident by frequent mcrease of nuclear and chromosomal abnormalltles, and occasional development of micronuclei in the root merlstem. Dilution of the effluents to 1 reduced the genotoxic effects generated in A. cepa roots by the final effuents_ The results revealed that waste treatment technologies m these two mdustnal zones need to be upgraded m order to ehmmate cytotoxlc and genotoxrc hazards associated with the treated effuents_ The results highlight the importance of incorporatmg practically feasible bioanalytical tools such as A. cepa root based test system on a regular basis for evaluating the efficacy of waste treatment technologies.Item New Records of Ants (Hymenoptera: Formicidae) from Sri Lanka, Including Four Tramp Species(Sociobiology, 2018) Dias, R.K.S.; Udayakantha, W.S.; Wachkoo, A.A.; Akbar, S.S.Five ant species are reported for the first time from Sri Lanka: Ooceraea alii (Bharti & Akbar, 2013); O. biroi (Forel, 1907); Prionopelta kraepelini Forel, 1905; Strumigenys emmae (Emery, 1890) and S. membranifera Emery, 1869. Among the newly reported species, four species (O. biroi, S. membranifera, S. emmae and P. kraepelini) are known for their invasive and tramping nature, spreading via human commerce and have attained broad cosmopolitan distribution. Impact of these ants on regional fauna is not known and needs immediate attention. A brief diagnosis, distribution, and illustrations are provided for each species.