International Postgraduate Research Conference (IPRC)
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Item Assessment of the Heavy Metal Concentrations in Mangrove Leaves of Negombo Lagoon(19th Conference on Postgraduate Research, International Postgraduate Research Conference 2018, Faculty of Graduate Studies,University of Kelaniya, Sri Lanka, 2018) Handagiripathira, H.M.N.L.; Deeyamulla, M.P.; Koichiro, S.Mangrove ecosystems play an important role in the biogeochemistry of heavy metal contamination in tropical coastal areas. During the last decades, heavy metals are one of the most serious contaminants in those environments due to its toxicity, durability and bioaccumulation problems with the long residence time within the food chain. Mangrove leaves are the primary producer of the food chains or food webs in mangrove ecosystems where there is a direct effect on the human health. The bioaccumulation levels of heavy metals in mangroves can be estimated by assessing such levels in leaves, sediments and water in the study area. This study was a part of a M.Phil. research and the main objective of this study was to assess the concentrations of selected heavy metals to understand the levels of contamination in the mangrove leaves in a selected lagoon system. The 27 locations of Negombo lagoon which is situated in urbanized area in Gampaha District of Sri Lanka was selected for the study. Four mangrove species of Rhizophor amucronata, Rhizophora apiculata, Avicennia marina and Lumnitzera racemosa were chosen since these arethe most common species in the lagoon. Mangrove leave samples categorized as young, matured and old and were collected in the wet and dry seasons of 2015 and 2016. Leave samples were cleaned and oven dried prior to grinding for fine powder. The elemental concentrations of heavy metals, Mn, Fe, Cr, Co, Ni, Cu, Zn, As, Hg and Pb were analyzed in the dried powder of mangrove leaves (297 samples) using Particle-induced X-ray emission (PIXE) technique established in Medical University, Iwate, Japan. The results were evaluated to study the spatial and temporal variations of heavy metal concentrations in mangrove leaves of the Negombo lagoon. The distribution of metals in mangrove leaves were departed and depended on the mangrove species as well as climatic seasons in study period. The most prominent species of R. mucronata, R. apiculata were represented by 262 samples and both species were having same concentration levels except Mn and Zn, which act as essential plant nutrients, were greater in R. apiculatathan the other species. The ranges of metal concentrations (in ppm) of R. apiculata leaves in the studied area were observed in the order: Mn (15.2-453.0) > Zn (5.4-276.4)> Fe (28.6-224.9) > Cu (0.1-9.3)> Cr (0.2-7.3)> Hg (ND-5.9)> Pb (ND-4.0)> Ni (ND-2.3)> Co (ND-1.7)> As (ND-1.0). The heavy metal uptake by young, matured and old leaves were showed significant deviations for most of the studied metals. Cr content in all leaves was same and some metals (ie. Fe) were higher in old leaves and some metals (ie. Zn) were higher in young leaves. A comparative evaluation of studied metals was carried out with the similar studies conducted in the world. In general, heavy metal concentrations in mangrove leaves of Negombo lagoon were lower than the permissible limits as recommended by WHO (1996), except Cr, Zn and PbItem Cadmium, Chromium and Lead Burden in Cooked Rice in Chronic Kidney Disease of Unknown Etiology (CKDu) Prevalent Areas(19th Conference on Postgraduate Research, International Postgraduate Research Conference 2018, Faculty of Graduate Studies,University of Kelaniya, Sri Lanka, 2018) Fernando, T.D.; Arachchige, Y.L.N.M.; Jayawardena, B.M.Chronic Kidney Disease of unknown etiology (CKDu) is a serious health problem in Sri Lanka since the 19th century. Still there is no permanent remedy for this problem. Madawachchiya is the area with highest number of CKDu patients and in this area people have stopped drinking well water as a precaution but they continue to use well water for cooking purposes. Heavy metals are among the suspected causes for CKDu. Heavy metal burden in rice may be increased when polluted water is used for cooking. However, studies have not been conducted to investigate the heavy metals fluctuation during cooking process in this area. Milled rice samples of BG 300 and well water used for cooking were collected from each area. Those collected rice samples were cooked traditionally. Samples were analyzed to determine the selected three heavy metal concentrations (Cadmium, Lead and Chromium). In this area 16% of raw rice samples contained high levels of Lead and 29% percent of raw rice samples contained high levels of Chromium which were higher than the maximum permissible level (MPL) recommended by the FAO/WHO (Codex Alimentarius). The Cadmium contents of all rice samples were less than MPL. But 45% percent of water samples had exceeded the Sri Lankan Standards (SLS) recommended level for Cadmium and thirteen percent of samples had exceeded SLS recommended levels for Chromium. But none of sample had exceeded the WHO recommended levels of Cadmium, Lead and Chromium. There was no significant change in Lead content during the cooking process (p>0.05), but Cadmium and Chromium were significantly decreased (p<0.05). The mean contents of Cadmium, Lead and Chromium in cooked rice samples were 0.057±0.031 mg/kg, 0.13±0.09 mg/kg and 0.77±0.211 mg/kg respectively. Even though having elevated levels of Chromium and Lead in raw rice samples and elevated levels of Cadmium and Lead in water used for cooking, those heavy metal concentrations of cooked rice were lower than the maximum permissible levels recommended by the FAO/WHO. Using well water for cooking purposes in Madawachchiya area has not increased the Cadmium, Lead and Chromium levels in cooked rice. To recommend using well water for cooking purposes further analyzing of other parameters in cooked rice is requiredItem Removal of Heavy Metals from Sewage Sludge by Floating Macrophytes; Eichhornia crassipes (Mart.) Solms., Pistia stratiotes L. and Salvinia molesta Mitch(19th Conference on Postgraduate Research, International Postgraduate Research Conference 2018, Faculty of Graduate Studies,University of Kelaniya, Sri Lanka, 2018) Kodituwakku, K.A.R.K.; Yatawara, M.D.M.D.W.M.M.K.The land disposal of sewage sludge generated from industrial waste water treatment plants is a major environmental concern as the sludge has been contaminated with heavy metals. Hence, immobilization of such metals prior to land disposal reduces the burden of posing environmental risks. The present study was therefore planned to assess the efficacy of Eichhornia crassipes, Salvinia molesta and Pistia stratiotes to control heavy metals in diluted sludge (1:5) from the Common Waste Water Treatment Plant (CWWTP) in Biyagama Export Processing Zone, Biyagama, Sri Lanka. Equal weights of the second generation of above three plant species were introduced to batch type constructed wetlands of 63 L capacity. The experimental set-up was kept for 28 days. The weekly harvested plant and sludge samples were pre-treated and digested using Mars 6 Microwave digester. The heavy metals Zn, Pb, Ni, Cd and Fe analyzed using Atomic Absorption Spectrophotometer (Analitikjena NOVA 400P). The methods used for sample preparation, digestion and quantificational analysis were established generating satisfactory analytical precision. Statistical analysis was performed using Minitab 14 software. The results revealed that root accumulated much higher concentrations (more than 50.0%) of Fe, Zn, Pb, Ni and Cd than shoots. The plant uptake of Fe, Zn, Pb, Ni and Cd increased with increased exposure time. Nevertheless, the removal capability of metals by these plants differed from each other. S. molesta showed significantly higher Zn (36.0% in Cycle-1 and 40.0% in Cycle-2), Fe (26.6% in Cycle-1 and 25.6% in Cycle-2) and Ni(26.9% in Cycle-1 and 33.7% in Cycle-2) removals from sludge than E. crassipes and P. stratiotes by 28 days exposure period for both cycles (p < 0.05; ANOVA after arc-sign transformation of data). In addition, E. crassipes showed significantly higher Pb (41.2% in Cycle-1 and 46.4% in Cycle-2) removal than P. stratiotes and S. molesta. Moreover, P. stratiotes showed significantly higher Cd (27.1% in Cycle-1 and 29.3% in Cycle-2) removal than other two species (p < 0.05; ANOVA after arc-sign transformation of data). The present study concludes that floating macrophytes E. crassipes, S. molesta and P. stratiotes significantly reduce the heavy metals Zn, Pb, Ni, Cd and Fe from sewage sludge