IRSPAS 2019
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Item Investigation of metal concentrations in indoor and outdoor dust in Kelaniya area, Sri Lanka(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Silva, K. D. M.; Premaratne, W. A. P. J.Urban dust is often contaminated with heavy metals and has become one of the major problems in metropolitan cities which is difficult to be controlled. Kelaniya area in Sri Lanka is one such vulnerable location. Anthropogenic activities have contributed exclusively for the elevation of heavy metal concentrations in atmospheric dust and in the earth’s surface. Analysis of both indoor and outdoor dust therefore becomes an important tool in the prediction of the extent to which air pollution has taken place in a particular area. This can help to relate the threat for human health by toxic elements and to identify its impacts. This investigation was carried out by selecting two major locations at the vicinity of the Kandy- Colombo main road (A1) in Kelaniya area including the premises of University of Kelaniya which is located very close to the A1 main road. The sites lie in the GPS range of 6.969674 °N to 6.975092°N and from 79.913546°E to 79.923919°E. Ten sampling sites from indoor and outdoor locations were selected. Samples were collected as triplicates for six consecutive months from June to November 2018. They were analyzed for pH, conductivity, moisture, phosphorous content and organic matter. Concentration levels of five heavy metals Pb, Cu, Zn, Cr and Fe were also determined using atomic absorption spectroscopy. The preliminary factors that favor the persistence of heavy metals in the environment were investigated and analyzed. It was observed that acidic dust and organic nature favor heavy metal deposition. Among the heavy metals, Fe content was very high (1614-6134 mg/kg) in the dust samples. Cr levels (1.92-10.58 mg/kg) were very low. Pb content (21.09-84.52 mg/kg) was reasonably high. Zn level (14.72-42.48 mg/kg) and Cu level (6.0-45.0 mg/kg) were relatively abundant in almost all the samples. A good positive correlation was observed in between Pb- Zn, Pb-Fe and Pb-organic matter than other combinations assuring to a correlation coefficient greater than 0.5 in every instance. These results suggest that components of positive correlation have arisen from a common source and that dust comprised of high Zn or Fe concentration have a higher probability of Pb contaminationItem Analysis of heavy metal levels in rice grown in CKDu effected Krambankulama in Medawachchiya, Sri Lanka(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Dilrukshi, A. A. S.; Weerasooriya, M. K. B.Chronic Kidney Disease of unknown etiology (CKDu) is a major health problem faced in agricultural areas in North Central Province, Sri Lanka. Among many different causative factors that suspects, heavy metal contamination of food is one of the major issues which can lead to the renal failures in human. Though number of studies have been reported on CKDu, exact causative factor still remains unknown. Since rice (Oryza sativa) is the staple diet in these areas, heavy metal content of rice grown in CKDu prone Karambankulama, Medawachchiya was aimed to investigate. Rice samples (n=45) were collected from 5 sites in Karambankulama and in Hettipola, Kuliyapitiya. From each site 9 samples were collected at random locations. For the comparison purpose, Hettipola was selected as negative control site. The rice samples were acid digested in a microwave digester and heavy metals were analyzed using Atomic Absorption Spectrophotometer. Cu, Cr, Pb were detected in flame mode whereas Cd was detected in furnace mode. According to the results obtained mean metal contents of rice samples were as follows. Cu- 0.864±0.090 mg/kg, Cr- 0.903±0.020 mg/kg, Pb- 0.144±0.010 mg/kg and Cd-0.089±0.003 mg/kg for the samples collected from Karambankulama and Cu- 0.804±0.050 mg/kg, Cr- 0.895±0.010 mg/kg , Pb- 0.133±0.001 mg/kg and Cd- 0.061±0.001 mg/kg for the samples from Kuliyapitiya. There were significant difference (p<0.05) of the mean levels of Cu, Pb and Cd in rice between Karambankulama and Hettipola while there was no significant difference (p>0.05) with respect to the mean levels of Cr. To assess the safety of dietary intake, weekly intake of Cu, Cr, Pb and Cd in rice samples were calculated separately based on the daily consumption of rice and compared with the Provisional Tolerable Weekly Intake (PTWI) established by the WHO/FAO. The results indicated that weekly intake of Cr was higher for ages between 4-5 years and 14 years for both sites and that of Cd was higher for ages between 4-5 years in Karambankulama than the maximum weekly intake levels recommended by WHO/FAO. During the survey 12 CKDu patients were recorded in Karambankulama whereas none was recorded in Hettipola. Hence, Cd accumulation in the body over long period of time could be one of the causes for the present increase in chronic renal failure in the North Central province.Item Monitoring heavy metal air pollution using moss as a biomonitor and developing a mathematical relationship based on surrogate approach, to determine heavy metal loads in moss(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Yohani, A. A. R .; Deeyamulla, M. P.Atmospheric pollution is one of the major problems that mankind is dealing with. Under air pollutants, heavy metals are toxic and persist in the environment. Monitoring heavy metal loads in the atmosphere is therefore of immense importance for environmental studies. As direct monitoring instruments are expensive and difficult to handle in extreme conditions, the biomonitors can be used as an alternative, cost effective method to monitor heavy metal air pollution. In this study, Barbula unguiculata moss species was used as the biomonitor to determine atmospheric heavy metal content since it was readily available in all selected areas. Sampling areas were divided into 4 major categories i.e. Pettah and Borella under the heavy traffic areas, University of Kelaniya under the moderate traffic area, Kegalle (Nelumdeniya) under the less traffic area and Sapugaskanda as the model area for industrial pollution where number of major industries are present. In each study area, five sub sampling sites were chosen and those selected sites were triplicated. Five heavy metals (Cu, Cr, Zn, Pb and Ni) were analyzed using Flame Atomic Absorption Spectrophotometry. Sinharaja rainforest was treated as the background area where anthropogenic activities and industrial emissions were minimum. According to the native moss analysis, two heavy traffic areas, industrial area and moderate traffic area were in contaminated levels with all five selected heavy metals. Based on the calculated pollution load index values, atmospheric heavy metal pollution in selected areas follows the order, Pettah > Borella ~ Sapugaskanda > University of Kelaniya > Kegalle. Besides the atmospheric heavy metal loads, same heavy metal loads in soil samples from the same five areas were analyzed. The correlation analysis was performed and there was no any clear correlation among heavy metal loads in the atmosphere and the soil of the selected five areas as the soil heavy metal loads depend on several other external factors. It was found from the study that surrogate approach was an effective methodology for the determination of heavy metal contents by using only two surrogate heavy metals per each site. By using Pearson Correlation Analysis and Multiple Linear Regression Analysis, mathematical relationships were developed to estimate heavy metal loads and those were validated and the reliability was assessed.Item Heavy metal levels in Chanos chanos (Milk fish) from Negombo estuary, Sri Lanka and human health risk assessment associated with their consumption(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Bandara, P. R. C. S.; Pathiratne, A.Contamination of fish with toxic heavy metals can counteract the nutritional and health benefits of fish food on human health. Objectives of this study were to determine selected heavy metals levels viz. Aluminum (Al), Cadmium (Cd), Chromium (Cr), Copper (Cu), Lead (Pb), Nickel (Ni) and Zinc (Zn) in edible fish, Chanos chanos (Milk fish) from Negombo estuary and assess potential human health risks associated with their consumption. Muscle and liver of freshly captured C. chanos (n=20) from the estuary in 2018 were used for metal analysis. Metal levels were determined by Atomic absorption spectroscopy (graphite furnace method) following microwave digestion using standard analytical chemistry techniques. Two certified reference materials for trace metals were used to check the recovery of the metals based on the analytical method used in this study and recovery percentages were within a satisfactory range. Potential human health risks associated with the dietary exposure to these heavy metals through fish consumption were assessed using multiple approaches by comparing the thresholds viz. Maximum Permissible limit (MPL), Tolerable Daily Intake (TDI) and Target Hazard Quotient (THQ) stipulated by international food standards regulatory authorities. Of the seven heavy metals measured, mean metal concentrations in C. chanos followed the decreasing order, Zn≈Al>Pb≈Cr>Cd>Ni≈Cu in muscle and Zn≈ Cu > Al≈ Cd>Cr≈ Ni> Pb in liver respectively. Concentrations of Cr and Pb in the edible muscle were significantly greater (P < 0.05) than those in the liver of the fish. Human health risk assessment indicated that the detected concentrations of the heavy metals in the edible muscle of the fish were below the MPLs stipulated by international food regulatory authorities except for Cd in 35% of the fish (range 0.06 - 0.08 mg/kg wet weight). Based on mean metal concentrations in the fish muscle, estimated daily intake values for moderate level fish consumers were below the corresponding TDI levels suggested by the food regulatory authorities. THQs for respective metals in the fish muscle were greater than the threshold value of one for Cd (1.5) and Pb (1.7) indicating potential human health risks associated with these metals in edible muscle for non-carcinogenic effects. However estimated maximum allowable fish consumption rates are high enough to safeguard the risks associated with Cd and Pb for moderate level consumers. The results revealed that it is unlikely that the measured seven heavy metals in C. chanos would pose non-carcinogenic health risks to the moderate level fish consumers.