Browsing by Author "Azmy, S.A.M."

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Assessment of water quality and identification of pollution status of Negombo estuary in Sri Lanka
(Sri Lanka Association for Fisheries and Aquatic Resources, 2015) Mendis, B.R.C.; Najim, M.M.M.; Kithsiri, H.M.P.; Azmy, S.A.M.
Industrial pollution and domestic solid waste dumping are considered as the major pollution sources of the Negombo estuary. Based on the pollution inputs into the estuary, it is considered that different localities within the estuary are polluted at different rates. A study was done with the objectives to determine the levels of physico-chemical parameters of water quality with special reference to identified pollution sources. For this study, water samples were collected from fourteen sampling locations during one year study period from January to December 2014 and important physico-chemical parameters such as conductivity, Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), phosphate-P, Nitrate-N, Ammoniacal-N and heavy metal (Pb, Cd and Hg) levels were analyzed employing standard methods. The results revealed that the average conductivity of 24.8±13.6 ms/cm, concentrations of nitrate 0.81±0.87 mg/L, phosphate 0.27±0.31 mg/L and ammonia 0.15±0.27 mg/L levels were below the maximum permissible limits of the proposed tolerance limits for the discharge of industrial wastewater quality standards for Central Environmental Authority, 2001 in Sri Lanka. The values obtained on BOD 23.6 ±7.1 mg/L and COD 469.0 ±36.5 mg/L levels were much higher than the permissible threshold limits. Results indicated that the concentrations of heavy metals Pb, Cd and Hg in water were 0.01 to 0.005 ppm, 0.0 to 0.01 ppm and 0 to 0.013 ppm, respectively. The detected average concentration of mercury in water was above the standard limits. The results obtained for levels of BOD, COD and heavy metals revealed that high pollution takes place in industrial and domestic sewage sampling sites. The South region receives water mainly from Dandugam Oya which carries various effluents from Ekala industrial zone. East region receives discharge of effluents from mainly Katunayake industrial processing zone. North region of the estuary, the levels of BOD, COD and heavy metals in water were higher due to the discharge of industrial effluents and domestic solid waste into the estuary. The highest concentrations of BOD, COD and heavy metals were recorded in the Northern area followed by Southern, Eastern and Western regions indicating the pollution status of the estuarine water.
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.
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.
Spatial and Temporal Variation of Selected Physicochemical Parameters in Chilaw Lagoon in Sri Lanka
(Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2016) Maddumage, M.D.S.R.; Azmy, S.A.M.; Premaratne, W.A.P.J.
Chilaw Lagoon is an intermittently closed, shallow coastal lagoon located in the North Western province of Sri Lanka. Excessive shrimp farm development has resulted in pollution of the lagoon since the farms extract water from the lagoon and discharge the effluent to the same lagoon. This study investigated the seasonal and spatial variations of selected water quality parameters at fifteen different locations situated between 7° 29' 17'' to 7° 36' 25'' N latitude and 79° 47' 19'' to 79° 49' 02'' E longitude in the Chilaw lagoon for a period of six months (from March to August in 2016). Each water sample was analyzed at the sampling sites for pH, Electrical Conductivity (EC), Salinity, Dissolved Oxygen (DO), Turbidity, Air Temperature and Water Temperature as physical and chemical parameters. Nitrite Nitrogen, Nitrate Nitrogen, Ammoniacal Nitrogen and Dissolved Phosphate were also analyzed. According to the experimental results, pH values of water in the lagoon fluctuated from 6.7 to 9.3 and exceeded the proposed ambient water quality standards for fish and aquatic life. The lagoon DO levels varied from 1.25 to 6. 79 mg/L and the lower limit does not comply with the tolerance limit for fish and aquatic life. EC values ranged from 2.8 to 55.1 mS/cm and the corresponding Salinity variation was 2 to 35 ppt (parts per thousand). The surface water temperature and the turbidity of the water in the lagoon varied in the range of 27.4 to 33.9 ͦ C and 0.96 to 50.3 NTU respectively. Ammoniacal Nitrogen was detected from 0.01 to 0.25 mg/L. The maximum Nitrite Nitrogen value was 0.04 mg/L and it was 0.32 mg/L for Nitrate Nitrogen. The maximum level of Orthophosphate was observed as 0.29 mg/L. Therefore, pH, EC, DO, Salinity, Turbidity and nutrients showed a significant spatio-temporal variation that affects the aquatic life in the lagoon critically.