International Research Symposium on Pure and Applied Sciences (IRSPAS)
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Item Studying the behaviour of export quantities of Tuna fish in Sri Lanka(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Sachithra, S. A. L.; Liyanage, U. P.; Wijeyaratne, W. M. D. N.Being an island in the Indian Ocean, Sri Lanka claims a large sea area and abundant fish resource with high facilitate suitable for large scale fishery industry. According to the Central Bank of Sri Lanka, the contribution of fisheries to the Gross Domestic Production (GDP) of the country ranges between 1.3% and 1.6%. Consequently, fishery industry already plays a vital role in economics and social development of Sri Lanka. Due to weather conditions, seasonal effects, changes of government tax policies and trade agreements, e.g. GSP+ and etc., there is a high fluctuation in export quantity of fishery products in Sri Lanka. Thereby, it is essential to study the variation patterns and forecast harvest and income generated by fishery products towards monitory strategy planning. Among the various types of fish, tuna is one of the species that is important in financial earnings. Out of all fisheries exports, Sri Lanka earns the highest income worth 50.8% by exporting tuna fish in 2016, according to the statistics from Ministry of Fisheries and Aquatic Development of Sri Lanka (SLMFAD). This study was conducted to analyze the export quantities of tuna fish and forecast the future export quantities. Monthly export quantities from January, 2010 to June, 2018 were collected from SLMFAD. In preliminary analysis, United States, Japan, and Canada are identified as the top countries in which Sri Lanka exports the highest quantity of tuna fish. To study the changes in export patterns and their associated relations, Statistical Change-Point Analysis was conducted. The results revealed a high correlation between the changes of export patterns with events such as country’s peace restoration, economic stability, infrastructure facilities, introduction of different capacity changes and termination of development projects. Towards forecasting the export patterns time series data analysis techniques were used. Unit root tests; Augmented-Dickey-Fuller Test (ADF) and Kwiatkowski-Phillips-Schmidt-Shin test (KPSS) were used to test the stationarity of the time series data. Based on Akaike information criterion (AIC) value, SARIMA (1,1,2)(1,0,0)12 model was identified as the best. Ljung-Box test, Jarque-Bera test and Heteroscedasticsity test were used to check the behavior of the residuals of this fitted models. Accuracy of the models were compared by root mean squared error (RMSE), and mean squared error (MSE). With 0.8485 of RMSE and 0.6038 of MSE, SARIMA (1,1,2)(1,0,0)12 model can be considered as the most suitable model to forecast the export tuna quantity from Sri Lanka.Item Cyanophyceans as bioindicators of water quality in the Diyawannawa wetland, Sri Lanka(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Nanayakkara, D. B. M.; Wijeyaratne, W. M. D. N.Cyanophyceans, which is a group of phytoplankton, are important in maintaining the ecological balance in wetlands. The abundance of cyanophyceans is strongly influenced by environmental parameters. The objective of this study was to assess the abundance of cyanophyceans in relation to water quality and to identify possible bioindicator cyanophyceans in Diyawannawa wetland. Seven input streams to the Diyawannawa wetland were selected as study sites. At each site, pH, temperature, dissolved oxygen (DO), visibility, depth, salinity, conductivity, nitrate nitrogen (TN), dissolved phosphate (DP), total phosphate (TP), biochemical oxygen demand (BOD5), chlorophyll-a (Chl-a) and abundance and diversity of phytoplankton of family Cyanophyceae were identified from May to September 2018 following APHA standard methods. Spatial variation of water quality and abundance of cyanophyceans were assessed using one-way ANOVA followed by Tukey’s pairwise comparison. Pearson’s correlation analysis and regression analysis were performed to identify possible relationships among cyanophyceans and water quality of the wetland. MINITAB-14 was used for statistical analysis. Total of 19659 members of Cyanophyceae belonging to 13 species were recorded. Gloeocapsa sp, Merismopedia glauca, Microcystis aeruginosa, Microcystis incerta, Oscillatoria sp. and Spirulina sp. were present in all the sites and showed significant variations in their distribution. Anabaena sp. and Chroococcus limneticus were also present in all sites, but did not show significant differences of abundance. Significant variations of TN, DP, TP, salinity, conductivity, DO, visibility, BOD5 and Chl-a were recorded (p<0.05). Pearson’s correlation analysis was performed to assess the relationship between the abundance Cyanophyceans with water quality parameters. Spirulina sp. showed strong positive correlations with conductivity (r=0.981, p=0.000), salinity (r=0.995, p=0.000), TP (r=0.962, p=0.001) and DP (r=0.996, p=0.000). Oscillatoria sp. also showed strong positive correlations with salinity (r=0.992, p=0.000), conductivity (r=0.982, p = 0.000), TP (r=0.967, p=0.000) and DP (r=0.996, p=0.000). Further, both Spirulina sp. (r=0.763, p=0.046) and Oscillatoria sp. (r=0.759, p=0.048) showed strong negative correlations with TN. Linear regression analysis between the abundance of Spirulina sp. and Oscillatoria sp. with conductivity, salinity, TP, DP and TN indicted that abundance of both species are influenced by conductivity, salinity, TP and DP (R2>90%, p=0.000). The results of the present study suggest that there is a possibility of using Spirulina sp. and Oscillatoria sp. as biological indicators of high TP, DP, salinity and conductivity in the Diyawannawa wetland. It is recommended to conduct more biological assessments to determine the suitability of using these cyanophyceans as bioindicators in other wetlands in Sri Lanka.Item Application of Allium cepa bioassay to study the spatial variation of potential cytotoxicity in relation to water quality in the Dandugan Oya, Sri Lanka(Research Symposium on Pure and Applied Sciences, 2018 Faculty of Science, University of Kelaniya, Sri Lanka, 2018) Wadasinghe, L. G. Y. J. G.; Wijeyaratne, W. M. D. N.Water quality is an important indicator in measuring the health of aquatic ecosystems. Poor water quality can lead to ecological health impairment. Dandugan Oya is receiving industrial waste from multiple sources. In addition, the raw water for the public water supply in some suburban areas in the Gampaha District is obtained from the Dandugan oya. In this study, potential cytotoxic effects of the water in selected sites of the Dandugan Oya were assessed using Allium cepa bioassay. Surface water samples were collected from six sites (Site A: Urban site; B and D: Industrial sites; C: public water supply intake; E: Agricultural site; F: Reference site with pristine environmental conditions) at two month intervals from May to November 2017. Water samples were collected from each site (n=10) and temperature, pH, conductivity, biochemical oxygen demand (BOD), dissolved oxygen concentration (DO), total dissolved solids (TDS) and chemical oxygen demand (COD) were analysed using standard analytical methods. Potential cytotoxicity of these water samples were assessed using Allium cepa bioassay. Spatial variation of water quality and cytotoxic end points were analysed by ANOVA followed by Tukey’s pairwise comparison using MINITAB 14 software. Significantly lower DO was recorded from sites C (4.0 ± 0.3 mg/L) and D (4.3 ± 0.4 mg/L) and significantly high COD was recorded from site D (267.1 ± 56.5 mg/L) (p<0.05). Significantly high TDS and conductivity were recorded from sites A and B (p<0.05). Mean nuclear abnormalities of the root tip cells of the A . cepa bulbs exposed to the surface water samples collected from the study sites ranged from 9‰ to 83‰ where significantly higher (p<0.05) nuclear abnormalities were recorded from site C (83 ± 2.4‰). Occurrence of nuclear buds and condensed nuclei in the interphase cells of the A . cepa root tips exposed to water samples from the site C (18 ± 0.8‰ and 61 ± 2.0‰) were significantly higher compared to the reference site (2 ± 0.1‰ and 4 ± 0.1‰)(p<0.05). Further, Site D also showed significantly high (p<0.05) nuclear bud formation (15 ± 0.4‰) and highest binuclei formation (6‰ ± 0.2) compared to the reference site. The results of the present study indicated occurrence of potentially high cytotoxicity in the A . cepa bioassay in the water at site C, which is the water intake site of Dandugan Oya for public water supply. Therefore, further investigations on the identification of the active forms of cytotoxic contaminants and continuous monitoring of water quality in these sites of Dandugan Oya is important in order to maintain the ecosystem and human health.Item Efficacy of Phyllanthus emblica bark powder in reducing total hardness of domestic well water in Jaffna peninsula, Sri Lanka(Research Symposium on Pure and Applied Sciences, 2018 Faculty of Science, University of Kelaniya, Sri Lanka, 2018) Shanthamareen, M.; Wijeyaratne, W. M. D. N.Jaffna peninsula is underlain by thick Miocene limestone deposits and these geological formations result in increased hardness of ground water. Increased hardness of drinking water can result in severe health effects including higher risk for urinary and salivary stone formation, urolithiasis and chronic kidney disease. The present study was conducted to evaluate the potential of the Phyllanthus emblica bark powder to be used as a home remedial method to reduce total hardness of drinking water. Water samples with three replicates were collected from 15 domestic wells from Kondavil area, Jaffna peninsula. The total hardness (TH), pH, temperature, Dissolved Oxygen (DO), Electrical Conductivity (EC), salinity, nitrate-N and Total Phosphorous (TP) concentration of these water samples were measured using standard methods (APHA). The water quality parameters were compared with the Sri Lanka Standards Institution (SLSI) drinking water standards . The pH and TP concentration of wells were within the SLSI drinking water standards. However, all the tested wells exceeded the total hardness concentration (250 mg/L) and 60% of the wells exceeded total nitrate (11.3 mg/L) concentrations established by SLSI for safe drinking water. The mean TH of the wells ranged from 454.8 to 784.4 mg/L CaCO3 and the mean nitrate-N ranged from 0.82 - 20.99 mg/L respectively. Well water samples were then filtered in a column filter using Phyllanthus emblica bark powder and the total hardness and total nitrate of the filtered water samples were measured . The variation of these parameters before and after filtration were compared by paired t test using MINITAB 14 software . After filtration through the Phyllanthus emblica bark powder, a significant reduction (paired t-test, p<0.05) of TH was observed with a 9 . 50% reduction . However, filtration through Phyllanthus emblica bark powder increased the nitrate concentration (4.89%). Therefore, it was concluded that Phyllanthus emblica bark powder could be used as a remedial method to reduce hardness in drinking water .