Symposia & Conferences
Permanent URI for this communityhttp://repository.kln.ac.lk/handle/123456789/10213
Browse
4 results
Search Results
Item Bioaccumulation of nephrotoxic metals in rice grains (Oryza sativa) in a CKDu hotspot in Sri Lanka via soil analysis(Institute of Chemistry Ceylon Adamantane House, Rajagiriya, Sri Lanka., 2020) Dayananda, M. D. N. R.; Liyanage, Janitha A.Accumulation of nephrotoxic metals in edible crops and associated soil is a major international concerns today which results food safety issues and adverse health risks like CKDu. Soils are considered to be an excellent media to monitor and assess chemical pollution where the application, deposition and absorption of chemicals are taken place. Therefore, this study attempts to investigate the bioaccumulation of nephrotoxic metals in soil and rice grains (Oryza sativa) and to interpolate the spatial distribution of selected chemical elements using Inverse Distance Weighted (IDW) and Spatial Autocorrelation tools in ArcMap 10.2.2 software in a CKDu hotspot; Girandurukotte Grama Niladhari Division (GND), Badulla, Sri Lanka via soil analysis. Dambethalawa GND in Ampara district was selected as the reference site. 30 soil samples were collected according to random stratified design including 10 paddy cultivated sites and 10 composite rice grain samples were collected from those paddy fields separately. Microwave digested soil and rice samples were analyzed by inductively coupled plasma mass spectrophotometry. The average concentrations of Cd, Pb, As, Cr, Ca and Mg in soil were 0.45±0.02, 0.20±0.02, 0.65±0.25, 0.29±0.04, 4812.00±692.00, and 15157.00±1275 mg/kg respectively. According to the lower Moran’s indices given by the Spatial Autocorrelation, the selected metals were evenly distributed throughout the sampling area and Cd, Pb, Ca and Mg contents in CKDu prevailed area was significantly higher (p<0.05) than the reference. The higher bioaccumulation factors (from soil to rice grain) (BCF>1) indicated that rice grains tend to accumulate the nephrotoxic metals including Cd;2.35, Pb;7.48, As;2.60 and Cr;5.80. The calculated Enrichment factors (EF) which derives the degree of soil contamination by nephrotoxic metals were Cd;6.49, Pb;6.01, As;1.30 and Cr;1.48 and greater EFs (EF>1) indicates higher availability and distribution of metals in contaminated soil when compared to the reference. It can be concluded that the degree of soil contamination by nephrotoxic metals was higher in the selected CKDu hotspot than the reference. Hence, human renal dysfunctions can be related with consumption of contaminated rice with those metals.Item Effect of fertilizer application to the agricultural soil and the determination of soil to plant transfer coefficients of selected elements(Institute of Chemistry Ceylon Adamantane House, Rajagiriya, Sri Lanka., 2020) Perera, W. P. R. T.; Dayananda, M. D. N. R.; Botheju, W. S. M.; Liyanage, Janitha A.Transfer of metals from soil to plant depends on the availability of particular elements in soil and the fertilizer which are applied to the agricultural fields. This study aims to determine the effect of fertilizer application to the agricultural soil and to determine the soil to plant transfer coefficients of selected elements in Eppawala Grama Niladhari Division (GND), Anuradhapura, Sri Lanka. Fifteen soil and rice root samples were randomly collected from paddy fields and composite fertilizer samples were prepared by adding Urea, Muriate of Potash and Rock Phosphate in the ratios which were used by farmers in sampled area. Metals were analyzed by Inductive Coupled Plasma Mass Spectrometry (ICP-MS-Agilent 7800). Mean concentrations of Cr, Fe, Cu, As, Cd, Pb and Zn in fertilizer composites were 445.00±171.00, 114638.00±46722.00, 92.90±38.40, 178.00±109.00, 5.56±3.41, 912.00±534.00 and 2553.00±1452.00 in mg/kg respectively. Mean concentrations of Cr, Fe, Cu, As, Cd, Pb and Zn in soil samples were 0.22±0.03, 135.10±38.90, 1.37±0.16, 0.25±0.30, 0.01±0.00, 0.32±0.07 and 40±10.3 in mg/kg respectively. The transfer coefficients (TC) of different metals were quantified to indicate the lability of metals in soils. Greater TC value indicates relatively poor retention of metal in soil or greater efficiency of plant roots to absorb metal, and low TC is attributed to strong sorption of metal to the soil colloid. TCs from soil to roots for Cr, Fe, Cu, As, Cd, Pb and Zn were 62.14, 260.04, 46.93, 6.94, 21.26, 14.14 and 3.37 respectively. It indicates that rice roots absorb higher amounts of metals in soil colloids which are resulting mostly from the fertilizer applications. It can be concluded that considerable amount of metals coming from the fertilizers are remaining in the soil and the efficiency of absorbing metals from plant roots is higher than the retention of metals in soil as having greater Transfer Coefficients.Item Investigation of spatial distribution of fluoride in drinking water sources in CKDu prevalence areas in Sri Lanka using GIS(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Dayananda, M. D. N. R.; Botheju, W. S. M.; Perera, W. P. R. T.; Liyanage, J. A.Chronic Kidney Disease of unknown etiology (CKDu) has identified as a significant health burden in rural dry zone areas in Sri Lanka. Fluoride is recognized as a nephrotoxic contaminant which deteriorates the renal functions progressively and the drinking water could be the major source which is responsible for the disease occurrence. Therefore, the present study attempted to investigate the spatial distribution of fluoride in drinking water sources in CKDu prevalence hotspots in Sri Lanka using Geographical Information System (GIS). Triplicated drinking water samples were collected from 30 sampling locations (from dug wells) in each Grama Niladhari Division (GND) including Wewelketiya GND in Anuradhapura district, Ambagaswewa GND in Polonnaruwa district, Naminigama GND in Mathale district and Buddhangala GND in Ampara district (Reference site) in dry season, Sri Lanka (February – March, 2019). Fluoride contents of collected samples were analyzed using ion chromatography (Metrom Eco_IC instrument). Spatial distribution patterns were interpolated using inverse distance weighted (IDW) and spatial autocorrelation (Moran’s Index- MI) tools in ArcMap 10.2.2 software. Results indicated that the mean fluoride levels of the collected water samples of Ambagaswewa and Wewalketiya areas were 1.37 ± 0.66 mg/L and 1.26 ± 0.65 mg/L respectively and those results exceeded the Sri Lankan drinking water standards (SLS 614: 2013) (1.0 mg/L) but the mean fluoride levels relevant to Naminigama area (0.82 ± 0.59 mg/L) complied with the SLS standards. Further 80% of the samples in Ambagaswewa GND and 95% of samples in Wewalketiya GND were highly contaminated with fluorides which were exceeded the SLS standard limits. Significantly higher Fluoride concentration levels were shown in Ambagaswewa GND (P= 0.103) and Wewalketiya GND (P= 0.704) compared to the reference area of the study.As well as fluoride concentration of the reference area was evenly distributed (MI= -0.005) in very low levels compared to the selected hot spots. Fluoride distribution were clustered with higher levels (MI = 0.31) in Wewalketiya GND, and Fluoride levels were evenly distributed with higher levels in Ambagaswewa GND and Naminigama GND with the Moran’s Indices of -0.12 and -0.07 respectively. It can be concluded that fluoride can be one of the risk factors affecting the prevalence of the CKDu. As the people are at a risk with the long-term exposure to the high fluoride concentrations, it is very essential to innovate a proper and affordable drinking water treatment technology for the affected areas and findings of this study can be used as background water quality data in the design processItem Estimation of crop management factor and conservation support practice factor of RUSLE model to assess vulnerability to soil erosion in Kalu Oya and Mudun Ela basins using GIS(Research Symposium on Pure and Applied Sciences, 2018 Faculty of Science, University of Kelaniya, Sri Lanka, 2018) Lekamge, M. L. D.; Dayananda, M. D. N. R.; Weerasinghe, V. P. A.Soil erosion is a serious environmental problem, which emerges from intense anthropogenic activities, agricultural practices and improper land use management. River basin soil erosion assessment enables to plan, conserve and manage the watershed areas and associated ecosystems. Revised Universal Soil Loss Equation (RUSLE) model is the most widely used model to predict the long term erosion rates in an area using rainfall-runoff erosivity factor, soil erodibility factor, slope length and steepness factor, crop management factor (C factor) and conservation support practice factor (P factor). Present study has been conducted to estimate the C and P factor to assess the vulnerability to soil erosion in Kalu Oya and Mudun Ela basins located in Gampaha district, Western province, Sri Lanka. The total catchment area of Kalu Oya and Mudun Ela basins (7°7'60" N and 79°54'0" E) are about 78 km2. C and P factor of RUSLE model were estimated using land use map and 30m resolution LANDSAT 8 OLI/TIRS satellite images acquired on 17th February, 2018 to determine the vulnerability of erosion and conservation status. The C factor values for barren areas and well protected areas were assigned from 1 - 0 respectively, whereas 0 - 1 range was used for the good conservation (0) and poor conservation (1) status of the prevailing land use patterns using the field observations and literature reviews. Spatial join tool of overlay analysis was used to obtain the combined effect of C and P factors and two separate thematic maps were derived using ArcGIS 10.2.2 version to represent the spatial distribution of both C and P factors according to five classes; low, moderate, high, very high and extremely high which represent the vulnerability to soil erosion. The study identified 9.94% of the total area with 0.00 - 0.01, 80.56% with 0.01 - 0.14, 0.61% with 0.01 - 0.20, 8.03% with 0.20 - 0.63 and 1.86% with 0.63 - 1.00 of C factor and 0.01% with 0.20, 0.61% with 0.20 - 0.40, 82.57% with 0.4 - 0.5, 1.45% with 0.50 - 0.60, 15.35% with 0.60 - 1.00 P factor. Significantly higher amount of erosion vulnerability areas were observed besides the tributaries. The study identified 9.01% of the total area under low erosion (0.00 - 0.02), 79.56% under moderate erosion (0.02 - 0.14), 0.61% under high erosion (0.14 - 0.20), 8.03% under very high erosion (0.20 - 0.63) and 1.86% under extremely high erosion (0.63 - 1.00) for combined effect of C and P factor. Moderate erosion could be reduced using suitable agronomic practices. Appropriate conservation measures have to be implemented for the areas under high, very high and extremely high vulnerability to soil erosion within the Kalu Oya and Mudun Ela basins to reduce sediment transport.