Browsing by Author "Kithsiri, H.M.P."

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Assessment of current water pollution status and accumulation of trace metals in Mugil cephalus from Negombo estuary
(Journal of Threatened Taxa, 2021) Najim, M.M.M.; Kithsiri, H.M.P.
Industrial and domestic solid waste dumping are the major pollution sources polluting the Negombo estuary. Polluted water and sediments in the estuary may cause heavy metals accu mulation in fish. Therefore, this study was aimed to assess physico - chemical parameters in water, heavy metals (Zn, Pb, Hg, Cd, Cu and Cr) in water and fish tissues, to compare the levels of metals in fish tissues with the available maximum recommended standards. The study was carried out from January to December 2016 and monthly sampling was done from the selected sampling sites. Physico - chemical parameters and metal levels were detected through standard methods. Water quality results revealed that temperature, salinity, pH, EC, TSS, BOD and nutrient levels were below the maximum permissible limits and COD levels were higher than the discharge of industrial wastewater quality standards of the CEA, Sri Lanka. According to the results, metal levels in water of the estuary were below the tolerance limits for the wastewater standards of the CEA except for Hg. In the Northern region of the estuary, higher Pb, Cu and Cr levels were reported from the fish species collected. As the “X-Press Pearl” shipwreck has posed a serious threat to the Negombo estuary, this study can be considered as a baseline for the future studies on water and sediment pollution and bioaccumulation of heavy metals in edible fish species from the estuary.
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.
Cadmium and arsenic levels in edible fishes, Oreochromis niloticus (Nile tilapia) and Ompok bimaculatus (Pena walaya) from Padaviya reservoir of North Central Province, Sri Lanka
(Research Symposium on Pure and Applied Sciences, 2018 Faculty of Science, University of Kelaniya, Sri Lanka, 2018) Weerasekara, K.A.W.S.; Pathiratne, A.; Kithsiri, H.M.P.
Oreochromis niloticus (Nile tilapia) and Ompok bimaculatus (Pena walaya) are two edible fish species captured in the reservoirs in the North Central province. Objective of this study was to assess the cadmium and arsenic levels in muscle, liver and kidney tissues of O. niloticus and O. bimaculatus inhabiting the Padaviya reservoir to assess association of metal/metalloid levels in tissues with body weights, and total lengths of the fishes. The body weight (180-300g; 110-225g) and the total length (19.0-24.1cm; 24.0-34.0cm) of Nile Tilapia (n=30), and Pena walaya (n=30) respectively were recorded during three sampling events in 2018. The tissues were analyzed for cadmium and arsenic levels using Inductively Coupled Plasma Mass Spectrometry. Cadmium and arsenic contents of the muscle tissues were below the limit of detection (LOD) (<0.05 mg/kg wet weight) except cadmium in the muscle tissues of five Nile tilapia (0.05-0.10 mg/kg). Cadmium contents in the liver tissues of both Nile tilapia and Pena walaya, ranged from <0.05 to 0.14 mg/kg (wet weight) where cadmium levels of 67-70% of the fishes were below the LOD. Arsenic levels in liver tissues of Nile tilapia and Pena walaya were <0.05–0.10 mg/kg and <0.05–0.06 mg/kg respectively where arsenic levels in 83% of Nile tilapia and 97% of Pena walaya were below the LOD. Cadmium content in the kidney tissues of Nile tilapia and Pena walaya were <0.05-0.90 mg/kg and <0.05-0.40 mg/kg respectively where cadmium levels in 30% and 33% fishes were below the LOD. Arsenic was detected only in kidney tissues of 10% Nile tilapia (<0.050.46 mg/kg). Cadmium contents in liver tissues of Nile tilapia positively correlated (p <0.05) with the total length. No other significant associations were found between the metal/metalloid content in the tissues and the body size of the fishes. Results revealed that the cadmium and arsenic contents in the edible muscle tissues of most of these fishes were within the safe limits specified by the regulatory authorities for human consumption. Bioaccumulation pattern of cadmium in the tissues of both fishes followed the order: muscle < liver < kidney, showing greater cadmium bioaccumulative capacity in the kidney tissues. Periodic monitoring of metal/metalloid levels in edible fishes in Padaviya reservoir is recommended considering human safety. The data generated in this study can serve as baseline information for future monitoring and human health risk assessment programmes.
Combination of Physico-Chemical Analysis and A Plant Bioassay for Screening Potential Toxicity of Drinking Waters in Selected Dug Wells in Medawachchiya Area, Sri Lanka: A Preliminary Study
(Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2016) Weerasekara, K.A.W.S.; Pathiratne, A.; Kithsiri, H.M.P.
Chronic Kidney Disease of unknown aetiology (CKDu) is becoming a major health problem especially in the North Central Province of Sri Lanka showing the highest prevalence in Medawachchiya area. Aetiology of this disease seems to be multifactorial which includes chronic exposure to environmental toxicants. This study reports the preliminary results of an ongoing study which has mainly focused on evaluating potential toxicity of drinking water in the dug wells in the Medawachchiya area using combination of physico-chemical analysis and bioassays.Eight dug wells were selected for the study using judgmental sampling method which included four drinking water sources of CKDu affected families and four wells which have been used by the families with no clinical signs of CKDu (Reference wells). Water samples obtained from these wells during prolong dry season in August 2016 were analyzed for physico-chemical parameters and the herbicide glyphosate using standard analytical methods.Potential toxicity of water samples was examined by the bioassay with the plant model (Allium cepa) following standard protocols with aged tap water and mineral water as negative controls. Results revealed that total hardness of the water of dug wells used by CKDu affected families were above the standard limits (250 mg/L, SLSI:2013). Alkalinity levels of water of all the wells used by the CKDu affected families and one reference dug well also exceed the stipulated limits for drinking water (200 mg/L, SLSI:2013). Arsenic was detected (2.0 μg/L) in water of one dug well used by CKDu affected families. Glyphosate was not detected in all drinking water samples (< 5 μg/L, detection limit). The bioassay indicated potential toxicity associated with water in the dug wells used by CKDu affected families based on A. cepa root growth retardations effect compared to negative controls and reference dug wells (P < 0.05). Further studies will be continued using bioassays with plant and animal models covering different climatic seasons in order to evaluate potential toxic/cytotoxic/genotoxic effects associated with the drinking waters of the dug wells used by CKDu affected families.
Distribution, Population dynamics and fishery of three species of bivalves (Family: Veneridae) in Puttalam lagoon and dutch bay, Sri Lanka
(1996) Kithsiri, H.M.P.
Factors affecting the abundance of three commercially important bivalve species (Family: Veneridae) in Puttalam Lagoon and Dutch Bay, Sri Lanka.
(Sri Lanka Association for Fisheries and Aquatic Resources, 1995) Kithsiri, H.M.P.; Wijeyaratne, M.J.S.; Amarasinghe, U.S.
Influence of seagrass coverage on the abundance of three commercially important bivalve species in Puttalam lagoon
(National Aquatic Resources Agency, 1994) Kithsiri, H.M.P.; Wijeyaratne, M.J.S.; Amarasinghe, U.S.
Influence of some environmental factors on the abundance of three commercially important bivalve species (Family: Veneridae) in the Puttalam Lagoon and Dutch Bay, Sri Lanka
(Sri Lanka Association for Fisheries and Aquatic Resources, 2000) Kithsiri, H.M.P.; Wijeyaratne, M.J.S.; Amarasinghe, U.S.
Water temperature, salinity, seagrass coverage, organic matter content in the soil and soil texture play an important role in the distribution of bivalves. The present study was carried out to determine whether these parameters significantly affect the abundance of three commercially important bivalve species viz Gaffrarium tumidum, Marcia hiantina and Marcia opima in the Puttalam lagoon and Dutch bay. The abundance of these bivalves in the Puttalam lagoon and .Dutch Bay was found to be significantly correlated with salinity (r = -0.57, p< 0.05), seagrass coverage (r = 0.89, p<0.001) organic matter content in the soil (r= 0.91 p<0.001) and soil texture. It was also found that the organic matter content in the sampling sites were highly correlated with the seagrass coverage (r = 0.90, p<0.001). Therefore, it is evident that the seagrass cover significantly affects the abundance of bivalves in the Puttalam lagoon and Dutch bay probably through enhancing the deposition of bivalve larvae inhibiting the borrowing activity of predators and increasing the productivity via increasing the organic matter content in the soil and deposition of sediments. As such it appears that in resource management the conservation of seagrass beds should get high priority and thus the operation of fishing gear that arc harmful to seagrass beds such as push nets and drag nets has to be minimized.
Population dynamics of three commercially important bivalve species (Family:Veneridae) in Puttalam lagoon and Dutch bay, Sri Lanka
(Sri Lanka Association for Fisheries and Aquatic Resources, 2004) Kithsiri, H.M.P.; Wijeyaratne, M.J.S.; Amarasinghe, U.S.
Traditional Practices for Resource Sharing in an Artisanal Fishery of a Sri Lankan Estuary
(Asian Fisheries Society, 1997) Amarasinghe, U.S.; Chandrasekera, L.W.H.U.; Kithsiri, H.M.P.
In the Negombo estuary of Sri Lanka, there is an artisanal fishery for penaeid shrimp locally known as stake-seine fishery. Stake-seine nets, which can be fixed in specific sites close to the sea mouth, are used for catching shrimp that migrate from the estuary to the sea. According to regulations imposed by the fishing communities, use-rightss in the fishery are granted to descendants of certain fishing families in four villages. Among the stake-seine fishers who are organized into four rural societies, an effective mechanism has been evolved for resource sharing in the fishery over a period of several hundred years. For equity sharing of the resource, different fishing dates are assigned to the four rural societies, and fishing sites are allocated to individual fishers in each society using a lottery system. Sustenance of this traditional practice is due to the fact that the returns from the fishery are significant. Community-based management strategies for the fisheries in developing countries can therefore be defined by adopting relevant mechanisms found in these types of artisanal fisheries.