IPRC - 2019
Permanent URI for this collectionhttp://repository.kln.ac.lk/handle/123456789/20881
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Item Assessment of the Heavy Metals in Rice Grains Grown in Paddy Soil in CKDu Endemic Area in Eppawala, Anuradhapura(International Postgraduate Research Conference 2019, Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2019) Perera, W.P.R.T.; Dissanayake, D.M.U.C.; Kannangara, A.T.; Liyanage, J.A.Global public health attention is being focused on Chronic kidney disease due to significant prevalence and the enormous cost of the treatment process. It was revealed that longterm consumption of bioavailable metals in grains causes CKD in humans. Therefore, the present study was planned to assess the levels of heavy metals in rice grains grown in paddy soil in CKDu endemic area in Eppawala, Anuradhapura. The soil samples (n=30) were collected from paddy fields in Eppawala GN division. Rice plants with rice grains (n=30) were also collected from the same fields. Collected samples (soil, rice roots and rice grains) were digested using the microwave digester (MDS-6G). Concentrations of heavy metals (Cr, Fe, Cu, Zn, As, Cd, Pb) of the paddy soil, rice roots and ride grain samples were analyzed by ICP-MS (Agilent 7800). Based on the analyzed concentrations, Geo acumination indices were calculated to evaluate the heavy metal contamination conditions in the agricultural soil.The results indicated that the average concentrations of Cr, Cd, As and Pb in soil were 49.918 mg/kg, 0.107 mg/kg 5.033 mg/kg and 9.882 mg/kg respectively and they were 1.709 mg/kg, 0.027 mg/kg, 0.217 mg/kg, 0.566 mg/kg respectively in roots. Nevertheless, the lowest levels of metals were observed from rice grains (Cr, Cd, As and Pb were recorded as 0.342 mg/kg, 0.011 mg/kg, 0.035 mg/kg, 0.112 mg/kg respectively). According to the Igeo calculations, agricultural paddy soil in the Eppawala area has been moderately contaminated with Pb, As, Zn, and Cu. (Class 2). Nevertheless, Cd and Cr levels were between near to moderate contamination level. (Class 1). Although the levels of metals in rice grains were low, long term consumption of metal contaminated rice may contribute to chronic failure.Item Synthesis of Surface-Modified Graphene-Based Sand for Fluoride Removal from the Drinking Water(International Postgraduate Research Conference 2019, Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2019) Perera, W.P.R.T.; Fernando, W.S.K.; Premasinghe, N.; Liyanage, J.A.; Kumarasinghe, A.R.Graphene and graphene-based material such as graphene oxide (GO) are materials of great interest for potential applications in nanoelectronics, nanoelectromechanical systems, sensors, polymer composites, catalysis. As graphene does not possess its native oxide, GO is routinely obtained via the chemical treatment of either graphene or widely available regular graphite. Chemically exfoliated graphene with various oxygenated functional groups bound to sp2 basal plane and edges of graphene sheet is called graphene oxide (GO). The surface sites on commercial sand used in water treatment are dominantly negative (pH = 2.7), and chemically inert. Therefore, they show a low affinity for most of the contaminants present in drinking water. However, conventional sand filters are used in water turbidity removal. Graphene oxide (GO) was synthesized using the modified Hammer’s method and purified sand was coated with GO dispersion to make super sand which can be used for many purposes including water purification. Single GO coated super sand (GO1) and multiple coated super sand (GO2, GO3, GO4, GO5) were prepared. Optimization studies were done for the fluoride removal process by super sand. Multiple coated super sand and fluoride adsorbed super sand were characterized using Scanning Electron Microscopy (SEM), energy dispersive X-ray absorption (EDXA) spectra, Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD). When increasing the coating times, the Enhancement of the GO coatings on the sand surface was clearly depicted by the SEM images and later by later coatings of the GO were observed on the sand surface. Respective EDXA spectra were also taken from both samples which show higher carbon content for sand/GO5 sample than sand/GO1. EDXA spectra of the Fluoride adsorbed five times coated sand show a small percentage of F in addition to the C, O and Si in the spectrum. The FT-IR spectrum for graphite oxide shows major peaks at wavenumbers of 3427, 1744, 1630, 1186, and 875 and 576 cm -1 due to the functional groups such as –OH, C=O, C-O. More or less similar peak patterns were observed on GO coated sand and peak intensities have been decreased when increasing the coatings. A noticeable decrease of the intensity of the peak at 1070 cm -1, which is assigned to be originating from sand, is a clear indication of the formation of layers of GO covering the sand. A noticeable peak of the FT-IR spectrum of Fluoride adsorbed 3 times coated sand observed around 3500 cm-1. It may be due to the Fluoride bond with Hydrogen in the GO. The highest performance of fluoride removal is shown at pH 3.22 and 7.21 for Sand-GO-1 and Sand-GO-5, respectively. In both instances, the fluoride removal efficiency is around 70 % when 3 ppm initial fluoride was used. So finally it can be concluded that five times coated Sand-GO is most suitable for fluoride removal from the contaminated drinking water.Item Speciation Distribution of Analyzed Drinking Water in a CKDu Endemic Area in the Anuradhapura District(International Postgraduate Research Conference 2019, Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2019) Weerasinghe, A.A.V.N.; Perera, W.P.R.T.; Liyanage, J.A.Chronic Kidney Disease of Unknown etiology (CKDu) has been showing a spreading tendency among the agricultural zones in the North Central Province since the mid-1990s. Even though most of the studies have identified that the nephrotoxic heavy metal content in surface and ground water has not exceeded the permissible limits in the CKDu prone areas, long term exposure could influence on renal failures. The present study was attempted to study the chemical speciation of the contaminants in drinking water of CKDu endemic area in the Anuradhapura District. The areas selected for the study were Eppawala Grama-Niladhari division (GND) (8°8′33″N 80°24′10″E) in Anuradhapura District (Endemic site) and Dambethalawa GND (7°17'11.9"N 81°32'04.3"E) in Ampara District (Reference site). Nineteen drinking water samples from each sampling area were randomly collected. Basic physico-chemical parameters such as pH, conductivity, dissolved oxygen and Fluoride content were measured on-site. Concentrations of heavy metals (Cr, Mn, Fe, Cu, Zn, As, Cd, Pb) of the water samples were analyzed by ICP-MS (Agilent 7800) and counter-ion content (F-, Cl-, NO3-, PO43-, SO42-) was analyzed by Ion chromatography (Methorm eco IC). Chemical speciation modeling was performed by using the Visual MINTEQ 3.1 software based on the obtained concentrations. According to the results, the average concentrations of Cr, Cu, Zn, As, Pb were complied with SLS values for drinking water while Mn and Fe concentrations from both areas have exceeded the SLS values which are 100.00 and 300.00 μg/L respectively. The Mn concentration of Eppawala and Ampara were 173.99 (10.39-485.59) μg/L and 129.27 (1.089-239.86) μg/L respectively and for Fe it was recorded as 383.14 (0.18-867.44) μg/L and 526.21 (0.85-897.25) μg/l. Since the samples were collected randomly, the presence of Mn and Fe as heavy contaminants in some sites might be the reason for having a wide concentration range. The mean F- concentration of the Eppawala area was 1.80 (0.10-3.96) mg/L which exceeded the SLS maximum level (1.00 mg/L) while it was 0.45 (0.11-1.00) mg/L in Ampara which was below the SLS maximum limit. According to the speciation results, only species of Cr, Pb, Cd, Cu and Fe, namely Cr(OH)3, CrOH2+, Pb2+, PbOH+, PbCl+, PbSO4, Cd2+, CdCl+, CdSO4, Cu2+, CuOH+, Fe(OH)2+, showed higher variations of percentage distributions under the tested pH range of 4 to 9. Higher percentage distribution values of CdCl+, CdSO4, PbCl+, PbSO4, ZnSO4, MnSO4, CuSO4 were observed from the Eppawala area compared to Ampara area. Manganese, Cadmium, Zinc, Copper, Lead, Fluoride, Nitrate and Chloride species showed more tendency to exist as free ionic species such as Mn2+, Cd2+ , Zn2+, Cu2+, Pb2+, F-, NO3-, Cl- at pH 7 while Chromium, Iron and Arsenic were found as Cr(OH)3, Fe(OH)2+ and H3AsO3 at pH 7. Long-term exposure to different species formed by Cd, Pb, Cr, As and higher F- concentrations may have some significant effects in causing CKDu.