iPURSE 2015

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Activated coconut coir as Na⁺ and Mg ²⁺ adsorbents for desalination applications
(University of Peradeniya, Sri Lanka, 2015-11-06) Hettiarachchi, E.; Kottegoda, N.; Perera, A.D.L.C.
Inadequate supply of safe drinking water is one of the major global issues and desalination of sea or lagoon water would be a plausible solution. Conventional desalination techniques are costly, require large amounts of energy, thus renewable sources of energy or cheaper alternatives should be sought out. This study focuses on the investigation of the potential of laboratory prepared activated coconut coir (ACC) in removal of sodium and magnesium ions from saline water, which could be extended to desalination applications at domestic level. Activated coir is prepared by pyrolysis of raw coconut coir treated with 50% (w/w) phosphoric acid. The adsorption characteristics of synthesized activated coconut coir was determined by measuring iodine number and methylene blue (MB) value of synthesized product and compared with those of commercial samples. Fourier Transform Infrared (FT–IR) spectroscopy indicates the presence of oxygen containing functional groups that are responsible for the adsorption of cations in desalination applications. The X-Ray diffraction pattern indicates the presence of weak graphitic structure in synthesized ACC. Sodium and magnesium ion removal efficiencies are studied using standard NaCl and MgCl₂ solutions. For both Mg²⁺ and Na⁺, approximately 50% removal is observed. For seawater samples, 40% removal of both cations is achieved with ACC dosage of 80.0 g L-1. Repeated filtration studies indicate 72% removal for Mg²⁺ after 6 filtrations and 75% removal for Na⁺ after 10 filtrations from seawater. The equilibrium studies show that the adsorption behavior fits into Langmuir and Freundlich isotherms, implying homogeneous monolayer coverage and chemisorption for both sodium and magnesium adsorption. Regeneration of spent activated coir is achieved by back washing using distilled water followed by either treatment with conc. HCl (RA – ACC) or pyrolysis (RP – ACC). Regenerated samples are characterized using MB adsorption value and FT-IR spectroscopy. The removal capacity of regenerated ACC have been compared with fresh activated coir by determining percent removal of Mg²⁺ from 0.200 mol dm⁻³ MgCl₂ solution. 52% removal of Mg²⁺ was obtained by RP – ACC indicating its suitability in reuse.
Applicability of colorimetric organic matter determination and its relationship with total soil nitrogen for selected soils in Sri Lanka
(University of Peradeniya, Sri Lanka, 2015-11-06) Darshana, E.M.A.; Nandasesna, K.A.
Soil Organic matter determination using Colorimetric determination is a simple and less time consuming method which has not been tested for Sri Lankan soils yet. Soil Organic matter determination using Walkey and Black method (Volumetric determination) is a very common method. It is more laborious, time and chemical consuming. Relationship between soil Nitrogen level and colorimetric soil organic matter content is also useful to predict soil Nitrogen level. The objectives of this study were to investigate the applicability of colorimetric determination of soil organic matter to Sri Lankan soils and to investigate the relationship between soil Nitrogen and soil organic matter. Fourteen soils, varying in C content, were collected from agricultural fields at 0-30 cm depth differing in physico-chemical and other characteristics. In colorimetric method, 1 g soil samples were placed in 100 ml volumetric flasks followed by the addition of 10 ml of 1/6 N K₂Cr₂O₇ and 20 ml of concentrated H₂S0₄. The samples were mixed by swirling the flask and then and allowed to stand on a pad for 30 minutes in a fume cupboard. After bringing to a volume of 100 ml, the mixture was filtered and analyzed for light absorption at 600 nm using spectrophotometer. Colorimetric organic matter values showed strong correlation with organic matter determined by volumetric (Walkey and Black, 1934) method (r=0.95). Organic matter determined from both methods showed no significant difference. Colorimetric method organic matter values showed strong correlation with total Nitrogen (r=0.75). It is confirmed that colorimetric method can be used effectively and reliably to determine soil organic matter in Sri Lankan soils and total Nitrogen in soil can also be predicted.
Assessment of green space in the colombo city liaisons with gis and in-situ data
(University of Peradeniya, Sri Lanka, 2015-11-06) Madurapperuma, B.D.; Kuruppuarachchi, K.A.J.M.
Urban sprawl in Colombo City is increasing due to centralization of social and economic endeavors. Urban forests and green infrastructure make the city cleaner and healthier to raise the standard of environment quality and aesthetic beauty. This study examines the green urban space in Colombo City using geographic information system and green cover was compared with in-situ ground truthing data in selected locations. A supervised learning algorithm was adopted to classify ESRI base image to three major land-use/cover classes: green space, built-up and water using training samples within Colombo City. Landsat 8 satellite imagery that acquired on 14.04.2015 was used to calculate Normalized Difference Vegetation Index (NDVI). Then green space of the NDVI image was extracted using polygonal vector feature class of the classified image. The results showed that 29% of the area was green space, 67% was built-up and 4% was water. Coefficient of agreement (Khat) was calculated for the classified image resulting in 0.81 overall accuracy. The NDVI values showed the intensity of greenness of vegetation. The difference of NDVI values were compared using available base maps. Then NDVI results were utilized to assess the green space in the field systematically to gauge how species contributes for varying greenness. The results and the method adopted in this study eventually provide valuable insights for city planners and policy makers to establish new green urban space to uplift environmental quality of potential sites in Colombo City.
Assessment of nitrogen, phosphorous and potassium concentrations in different raw material vermiwash
(University of Peradeniya, 2015-11-06) Dilani, P.G.I.L.; Loganathan, P.
The study was carried out from November 2014 to April 2015 within the premises of Vavuniya Campus of University of Jaffna. The main objective of this study was to analyze nitrogen, phosphorus and potassium (NPK) concentrations of vermiwash (VW) prepared with different raw materials. Study was targeted on several other objectives such as to seek the handiness of recycling vegetable waste and mango leaves through VW preparation, to prepare VW from green plant species which cause trouble in the environment. Five plastic barrels were used to establish the vermi-bed. A tap was fixed at one horizontal limb of the container. Then, a base layer of small gravels was placed. Over that a layer of fine sand was placed. Then, a layer of top soil was added and it was covered with a layer of cow dung. Excess amount of water was sprayed and allowed to drain-off. After that the tap was closed. Four different types of raw materials, namely vegetable waste, mango (Mangifera indica) leaf litter, parthenium (Parthenium histeroporous) and water hyacinth (Eichhornia crassipes) were used for the preparation of VW. Control unit was maintained. In control, only top soil and cow dung bed were used without adding any extra feeding material. Locally available Earth worms (EWs) were collected from an open land field of Agriculture School in Vavuniya, where livestock wastewater discharges. Fifty surface and subsurface local EWs were introduced in to each vermi- bed. After 60 days of processing, 4.5 L of VW from each unit was collected after passing 5 L of water into each unit. Three samples from each Vermiwash preparation unit and control were collected for physiochemical analysis. Physiochemical characteristics of different raw material driven VW were analyzed using one-way ANOVA. Significant differences were observed between different raw material driven VW and control, including available nitrogen (P ≤ 0.0001), available phosphorous (P ≤ 0.0001), exchangeable potassium (P ≤ 0.0001). Highest concentrations of nutrients were recorded in Parthenium VW (highest ) and Vegetable waste VW (highest and highest K+). The pH of VW was slightly alkaline (7.6 – 8.4). Vermiwash with 1:5 dilution (V/V) was lying within a range of 7.1 - 7.4. Near neutral range of 5.5 - 8.5 is suitable for crop foliar spraying solutions. EC range of 0.5 –1.5 dS/m in soil indicates suitable condition for cropping. Electrical Conductivity (EC) of different types of VW with 1:5 (V/V) dilutions was confirmed range from 0.7 – 1.4 dS/m. This study confirmed feasibility of VW preparation with environmentally troublesome weeds (Parthenium and Water hyacinth). The vermiwash contains considerable concentrations of nutrients in it. Vermicomposting is increasingly becoming popular as an organic solid waste management strategy. The preparation of VW with selected raw material confirmed alternative solution for controlling vegetable waste and mango leaf litters because there is no garbage after prepared VW. The amounts of nutrients in VW will be sufficient to apply for leafy vegetables where low chemical fertilizer applications are prescribed. There is still a requisite of continuing study in this field ahead to, compare the effectiveness of VW application on crop growth with recommended chemical fertilizer application. That will find whether VW replace the chemical fertilizers fully or partially; and to confirm relationship between nutrients concentration in pure raw materials and after it is proceeded in to Vermiwash.
Awareness and distribution of Invasive alien species (ias) of flora in galigamuwa area
(University of Peradeniya, Sri Lanka, 2015-11-06) Warunasinghe,W.A.A.I.
Biological invasions happen either deliberately or accidentally and are considered as serious threats to the biodiversity and its irreversible impact to the biodiversity is second only to the habitat loss. Thirty common IAS of plants were selected and the study inquired whether the local people were well aware about IAS of flora and if so, whether these species have badly influenced the environment and farming activities and its distribution in Galigamuwa area. Primary data were collected through a pretested self-administered questionnaire and 65 households were selected by using Multi stage random sampling technique. Analysis was carried out based on descriptive statistics together with graphical interpretation. According to the depicted results, all the respondents (100%) were aware about IAS of flora. Majority of the respondents (46%) educated through newspapers. Only few respondents (6%) were aware about Guinea grass (Panicum maximum), one of the prominent IAS of flora in Sri Lanka. Moreover, very few respondents were aware about Rila Thana (Pennisetum polystachion) 2% , Wal Sudda (Austroeupatorium inulifolium) 12%, Mist flower (Ageratina riparia) 3%, Gal Goraka (Clusia rosea) 7%, welvet tree (Miconia calvescens) 6%, Kikiyu grass (Pennisetum clandestinum) 2%, Parthenium (Parthenium hysterophorus) 12%, Kattakumanjal (Myroxylon balsamum) 8%, Yellow cestrum (Cestrum aurantiacum) 3%, Blue stars (Aristea ecklonii) 2% and Arunadevi (Sphagneticola trilobata) 2%. According to the depicted results, respondents have not observed Kikiyu grass (Pennisetum clandestinum) and Rila Thana (Pennisetum polystachion) in their surroundings. Moreover, no respondents (0%) were aware about Gorse (Ulex europaes). Results revealed that, majority of the respondents have seen water hyacinth (Eichhornia crassipes) 69%, salvinia (Salvinia molesta) 54%, Katu pathok (Opuntia dilenii) 57%, Katakalu Bovitiya (Melastoma hirtum) 60%, Wathupalu (Mikania micrantha) 72%, Mahogani (Swietenia macrophylla) 74%, Lantana (Lantana camara) 55%, Podisingnomaran 62% in their surrounding environments. While 69% of the respondents were aware about pinus (Pinus caribaena), only 25% of them have seen pinus in their surroundings. Of the sample, majority of the respondents were aware about Ginikuuru Gas (Alstonia macrophylla) 51%, Wild sunflower (Tithonia diversifolia) 58%, Para (Dillenia suffruticosa) 58% and Yoda nidikumba (Mimosa pigra). Very few of the respondents were aware about Katu Andara (Prospis juliflora) 35%, cuscuta (Cuscuta compestris) 40%, Kadadasi Mal (Antigonon leptopus) and Cheena Pera (Psidium littorale) 25%. Of the sample, majority of the respondents (58%) were facing difficulties in their day to day lives due to IAS of flora and most of them (52%) try to control these plants. Majority of the respondents (43%) have observed the reduction of native plant species due to IAS of flora and 37% of the respondents do not have clear idea about the adverse impacts of IAS of flora. According to the results, 45% of the respondents have reported that IAS flora have badly affected to their aquatic environments.
Cation availability in buffered coco pith and the effect on growth of tomato (solanum lycopersicum) plant
(University of Peradeniya, Sri Lanka, 2015-11-06) Ranaweera, R.D.M.; Dharmakeerthi, R.S.; Gunasena, A.
Plant growth retardations are often reported when coir based soilless growth media is used in protected agriculture. This has been related to high Na and K concentrations in the coir pith and different buffering techniques have been proposed to rectify this problem. This study determines the cation availability in coir pith buffered with three chemicals and the growth and nutrient status of the tomato plant (Solanum lycopersicum) grown in these media. In a leaching column experiment, 0% and 100% of the Albert solution recommended for tomato in protected agriculture was applied into coir buffered with either water, , or . Cation concentrations were determined in leachates collected at six times in 42 days. In a greenhouse pot experiment, 0%, 50%, 100%, and 120% of the recommended level of the Albert solution were applied into tomato plants replanted in the three buffered coir medium. Growth and leaf nutrient concentrations of the tomato plants were measured after 42 days. Available Na and K concentrations were the lowest in coir pith buffered with (71 and 91mg/L, respectively) compared to those in coir pith buffered with (187 and 304 mg/L respectively) or water (138 and 287 mg/L, respectively). This was about 49 to 63% reduction for Na and about 70% reduction for K. When the Albert solution was added, Na availability became high, as high concentration of Ca and Mg in it get strongly adsorbed to exchangeable sites and replace Na+. Dry matter accumulation in plants grown in both and buffered coir was not increased when the Albert solution was increased beyond 50% of the recommended level. But in plants grown in water buffered coir, application of 100% of Albert solution was required to record the highest growth. Multiple regression analysis revealed that the change in phosphorous (78%) and calcium (10%) status of the plant could be the possible reasons for the observed variations in plant growth. The most effective buffer to reduce Na and K in coir was and coir could be used as a growth media efficiently by employing appropriate nutrient management strategies when they were buffered with different chemicals.
Chemical and isotope characteristics of kidney stones (urinary calculi) from Sri Lanka
(University of Peradeniya, Sri Lanka, 2015-11-06) Weerasinghe, A.; Abeygunasekera, A.M.; Senaratne, A.; Weerasooriya, R.; Chandrajith, R.
Mineralogical, chemical and isotope characteristics of fifty (50) urinary calculi samples collected from removal surgeries were investigated. Fourier Transform Infrared Spectroscopy (FT- IR) technique was used to determine the mineralogical composition while elements Na, K, Ca, Mg, Zn and Fe in kidney stones were determined using Atomic Absorption Spectrophotometry. Stable isotope ratios of V and 18O were measured with isotope ratio mass spectrometer (IRMS). Stone samples were classified into four mineral groups based on FTIR characteristics in which whewellite (calcium oxalate) stones are dominant among apatite, uric acid (uricite) and struvite stones. Apatite stones are enriched with trace elements compared to other stone types in which phosphates act as an important metal-bearing phase. Uricite stones showed the lowest trace metal contents. The of urinary calculi ranged between -34 and -17 ‰ whereas value of kidney stones varies from -8.94 and -26.72‰. Most samples, particularly whewellite and apatite-uricite stones indicated more depleted values (-32 to -34‰). Since the isotopic composition of animal biominerals reflect those of ingested food and water, the more depleted in kidney stones are possibly due to heavy consumption of C3 dietary components. The isotope fractionation between inorganic reservoirs and biominerals of human body is important to understand the sources of elements in such biomaterials.
Climate change adaptation practices in crop cultivation : case study in Anuradhapura district
(University of Peradeniya, Sri Lanka, 2015-11-06) Ranasingha, R.M.C.K.; Nanthakumaran, A.
Climate change, mainly the variation in rainfall in the recent past years, causes frequent floods and drought in many districts in the country. The variation in rainfall and frequent floods and droughts affect the crop cultivation, and thereby challenging the food security of the country. Further, it affects the livelihood of the farming community in the tank based agriculture systems which includes the major and the minor irrigation tanks. Many minor irrigation tanks receive water from rainfall, store and supply for agriculture during non-rainy season. Very often the water stored in the minor irrigation tanks is not sufficient to fulfill the water requirement for agricultural purpose, because of the limited tank storage. The objective of this study was to identify the adaptation measures practiced by the farmers to overcome the effects of climate change due to rainfall variation under minor irrigation tanks. Since Anuradhapura district lies in the dry zone of Sri Lanka and many small and marginal farmers involved in crop cultivation, it was selected for this study. Stratified random sampling was done to select 150 farm households from 15 minor irrigation tanks in Anuradhapura district. Primary data from the farm households using structured questionnaire and the rainfall data for the past 31 years from the year 1984 as secondary data from the Meteorology Department were collected for analysis. Percentage analysis and the graphical representation were carried out using MS Excel. During 1984 to 2014 the average annual rainfall was 1293 mm with a coefficient of variation of 22 percent. The rainfall was above normal in 13 years with a deficit in 13 years, and very scarce in five years. The survey revealed that the crop insurance, cultivation of short duration crops, cultivation of drought tolerant rice varieties, inter cropping, changing the planting and harvesting date and agro forestry were some of the adaptation strategies practiced by farmers in the study area. The percentage analysis revealed that 94% of the farmers had crop insurance, 90 % of the farmers cultivated short duration crops, 72% of the farmers switched to cultivation of drought tolerant varieties, 46% of the farmers practiced intercropping, 30% of the farmers changed the planting and harvesting date, and 28% of farmers practiced agro forestry strategy as adaptation measures for climate change. Though the farmers in the study area practiced these climate change adaptation strategies to some extent, dissemination of knowledge about appropriate adaptation strategies towards farming community is essential to protect the livelihood of the farm households, while ensuring the food security of the country. Thus, the farmers may be given proper support by supplying short duration and drought tolerant rice varieties and selected seedlings for agro forestry.
Communication and adoption of waste management practices of urban and semi-urban households in Trincomalee district
(University of Peradeniya, Sri Lanka, 2015-11-06) Ganegoda, P.; Wanigasundera, P.
Waste disposal has become a serious issue in Sri Lanka, making her one of the highest waste generating countries in Asia. Previous research findings state that the key to successful waste management system is the cooperation of citizens, which could only be gained through public awareness, which is lacking in Sri Lanka. Thus, the focus of this research was to find out the role communication has in creating awareness and promoting adoption of waste management practices. Moreover, the research specifically focused on finding out the communication channels by which people receive information of waste management and the message content of those channels affecting the level of awareness and adoption of waste management practices. The data gathered from three purposively selected Divisional Secretariat divisions based on the ethnicity, as the study area is a multi-ethnic area; 200 households were selected randomly from both urban and semi-urban GS divisions. Trincomalee Town and Gravets and Kinniya DS divisions, which are functioning under the urban councils, represent the majority of Tamil and Muslim populations, respectively, whereas Kanthale DS division functions under Pradeshiya Sabha represents majority of Sinhala population. Data were gathered using a questionnaire and analyzed using Statistical Package for Social Sciences. Results revealed that people received messages related to waste management by around 20 communication channels, which can be categorized into three: national mass communication channels, provincial formal communication channels, and informal communication channels. Among them, mostly used communication channel was the television. In addition, respondents used Public Health Inspectors, school education, Urban Council/Pradeshiya Sabha, and newspapers to receive information. However, a large amount of information respondents received was not directly related to waste management. The information received through school education, television, newspaper and non-governmental organizations showed a significant positive impact on awareness level, but, only school education had a significant positive impact on adoption level. In conclusion, the results emphasize that communication plays a major role in creating awareness of people regarding waste management. However, it alone cannot contribute to improve the adoption level, which requires the contribution of supporting services, such as the service of informal waste collectors and implementing rules and regulations.
Decolourization of crystal violet synthetic dye from aqueous solution by woody biochar
(University of Peradeniya, Sri Lanka, 2015-11-06) Wathukarage, A.; Iqbal, M.C.M.; Priyantha, H.M.D.N.; Vithanage, M.
Colour removal from textile effluents prior to their disposal is an emerging concern due to its adverse effects on the environment and public health. Biochar can be used effectively as a biosorbent for removal of dye contaminants. This study investigated the adsorption of a basic dye, Crystal Violet (CV), from aqueous solutions on to biochar derived from Gliricidia sepium pyrolysed at 700 °C (GBC700). Pyrolysis was done under a heating rate of 7 °C min⁻ ¹. The adsorption process was investigated through batch experiments by varying pH, adsorbent dose, initial dye concentration, and contact time. The sorbent dosage, initial dye concentration and contact time were set as 0.5 - 6.0 g L⁻¹, 5 - 200 mg L⁻¹ and 5 min - 24 hr, respectively. The effect of pH was determined through edge experiments at pH 3 to 9. The equilibrium data was analyzed using the Langmuir, Freundlich and Hill isotherm models. Pseudo first order, Pseudo second order and Elovich kinetic models were used to investigate the kinetic data. Results indicated that the optimal adsorbent dose was obtained at 2 g L⁻¹ and the optimum contact time was 12 hr. The adsorbed amount was increased from 5.5 mg g⁻¹ at pH 3 to 8.0 mg g⁻¹ at pH 9 while the equilibrium was reached at pH 7. Since higher pH conditions lead to increasing the negative charge density of GBC700 and the electrostatic attraction to the dye cations can be enhanced. Crystal Violet removal efficiency was 99% at 20 mg L⁻¹. According to the Langmuir model, maximum adsorption capacity was observed at 30.4 mg g⁻¹ at 30 °C. The experimental data fitted well with the Freundlich isotherm model (r² = 0.9788) and Pseudo second order kinetic model (r² = 0.9703) which suggests the importance of multilayer adsorption to heterogeneous sites in biochars. The adsorption process is highly pH dependent. Crystal Violet molecule may interact with the GBC700 through the mechanism of 𝝅-𝝅 electron donor-acceptor interactions between the π-electron rich graphene surface of biochar and 𝝅-electron deficient CV dye molecule. The use of Gliricidia biochar pyrolysed at 700 °C could be a sustainable solution to remove CV in aqueous media while compromising the waste problem by using Gliricidia byproduct.
Development of land suitability map to expand rubber in northern dry zone of Sri Lanka : a case study from Vavuniya district
(University of Peradeniya, Sri Lanka, 2015-11-06) Liyanaarachchi, L.A.T.S.; Karunaratne, S.B.; Sankalpa, J.K.S.; Wijesuriya, B.W.; Gajanayake, B.; Abeysinghe, D.C.
The land extent of traditional rubber growing areas in the Wet Zone of Sri Lanka is limited due to various development activities. Therefore, expansion of rubber into non-traditional areas is vital to increase the extent under rubber cultivation and to meet the production target of the country. This study was aimed at developing a land suitability model and using it for mapping of potential areas where rubber can be cultivated in the Dry Zone of Sri Lanka considering a case study from Vavuniya District. Weighted overlay analysis in Geographic Information System (GIS) environment was carried out to develop a land suitability model where weights for the main variables namely; annual cumulative rainfall, maximum and minimum temperatures, elevation, slope of the land and soil type were determined using Analytical Hierarchical Process (AHP). Once the land suitability map was derived, potential land areas where rubber can be cultivated in the district were identified. Results of the AHP revealed that rainfall, minimum temperature, maximum temperature, slope, elevation and soil type were allocated weights of 39%, 7%, 15%, 6%, 5% and 28%, respectively in the land suitability model. Furthermore, results revealed that out of total potential land for expansion of rubber cultivation in the Vavuniya District, 19,751 ha of land were “Moderately suitable” while 3,297 ha of lands were categorized under “Unsuitable” and “Most unsuitable”. As the Vavuniya District has no optimum soil condition for rubber cultivation, proper ways of amending soils should be carried out. The outputs generated from this study provide firsthand information for policy makers related to expansion of rubber in the Northern Dry Zone of Sri Lanka.
Effect of biochar on phosphorus availability and fixation in some rubber (hevea brasiliensis) growing soils of Sri Lanka
(University of Peradeniya, Sri Lanka, 2015-11-06) Nandasena, M.A.G.H.; Dharmakeerthi, R.S; Herath, H.M.S.K.
In most rubber [Hevea brasiliensis (A. Juss.) Muell. Arg.] growing soils, phosphorus (P) availability is very low and added P fertilizers become unavailable to the rubber plant due to strong fixation of it into Fe and Al oxide minerals prevalent in these soils. Some studies have observed that amending soils with biochar (BC), a co-product of thermochemical conversion of lignocellulosic materials into advanced biofuels, has increased the P uptake and cut down chemical P fertilizer usage in rubber nursery plants. Therefore, a laboratory incubation study was undertaken to determine the dynamics of soil P availability in three rubber growing soils amended with BC made from rubber wood (RWBC). Three soil types, i.e. Reddish Brown Latasolic (RBL) soil from Parambe, Reddish Brown Earth (RBE) soil from Thanamalwila, and Red Yellow Podsolic (RYP) soil from Payagala were amended with RWBC at 0, 2 and 5% by weight. The soil moisture content was maintained at 80% of water holding capacity and P availability was determined at 0, 1, and 4 weeks during the incubation period. P fixation of soils amended with RWBC was assessed using the Portch and Hunter (2002) method. Available P contents were very low (4.1 to 10.7 ppm) in the three soils and was in the order RYP < RBE < RBL. Application of RWBC increased the available P content by 3 to 7 folds and the increase was in the order of RBE < RBL < RYP. The available P content decreased with incubation time and the greatest decrease (52%) was in RBL while the lowest (42%) was in RBE soil at 4 weeks after incubation in 5% BC amended treatments. Among the three soil types studied the RYP soil had the lowest P fixation ability, while RBL was the highest P fixing soil. Application of BC decreased the P fixation in RBE and RBL soils but not in RYP soil. The greatest decrease was observed when RWBC was applied at 5%. Therefore, amending rubber growing soils with RWBC appears to have altered the dynamics of available P in a positive manner.
Estimation and management of mobile phone waste (m-waste) in Sri Lanka
(University of Peradeniya, Sri Lanka, 2015-11-06) Samarakoon, M.B.
Electrical and Electronic Wastes (E-Waste) are generated due to the rapid increase of technology and economic activities in developed and developing countries in the world. Currently, E-Waste shows the fastest growing waste stream of about 4% with comparison to other waste streams. Discarded or obsolete mobile phone wastes (M-Waste) represent the largest proportion of E-Waste stream. In Sri Lanka, demand for mobile phones is relatively high and a recent study revealed that the mobile phone penetration increased from 28% to 40% in past few years. Therefore, M-Waste management is an urgent requirement in Sri Lanka to protect the environment and public health. There are certain approaches taken to manage M-Wastes in Sri Lanka. National Implementation Plan for electronic waste in Sri Lanka is a part of a pilot project on environmentally sound management of electronic waste in Asia and Pacific. There are some regulations enacted on use and disposal of mobile phones and technical guidelines to manage used lead acid batteries. However, the steps that have been taken to manage M-Wastes in Sri Lanka are not sufficient. The objectives of this study were to estimate the outflows end-of-life of mobile phones and past and future trends in the generation of obsolete mobile phones in Sri Lanka. A combination of two models was used to achieve above objectives. At the first step, time series multiple life span model was used to estimate outflows end-of-life obsolete mobile phones. Then, the simplified logistic function model was used to estimate the values of obsolete mobile phones in the future. Data were collected from available records, telephone interviews and face to face interviews. Questionnaires were also distributed among people in various levels in the society. The results revealed that the average life span of a mobile phone is approximately three years and the different types of end-of-life of mobile phones included reuse, store, recycle, throw with other waste, and just open dumping. The percentages of different end-of-life were 50%, 20%, 12%, 11% and 7%. According to the logistic function model, the number of obsolete mobile phones by 2035 will be more than 20 million. The results of the study revealed that the obsolete mobile phones would be a severe problem in Sri Lanka in future. Therefore, it is necessary to encourage investors to implement recycling facilities in large scales to manage the problem of M- Waste in Sri Lanka.
Evaluation of the status in environmental flow maintainance at mangalathiriya anicut in Aththanagalu oya, Sri Lanka
(University of Peradeniya, Sri Lanka, 2015-11-06) Udayanga, N.W.B.A.L.; Najim, M.M.M.
Determination of the volumes of flows that should be maintained for the sustenance of the natural eco systems under pristine conditions (Environmental Flows [EF]), remains complicated and difficult, causing a challenging situation for the sustainable management of water resources in many countries. As a tropical developing country with agriculture based economy, Sri Lanka is in need of utilizing the available lentic and lotic water sources heavily to support its economy. Yet, the management of such water sources in an ecofriendly sustainable manner without significantly affecting, both the environment and the economy, requires the maintenance of environmental flows. Thus, the quantification and long-term maintenance of EF requirements of lotic waters has emerged as a crucial requirement in sustainable management of water resources. Therefore, the Range of Variability Approach (RVA) was devised to evaluate the sufficiency of the flows at the downstream of the Mangalathiriya anicut for the sustenance of downstream riverine ecosystems. The Hydrologic Engineering Centre - Hydrologic Modelling System (HEC-HMS) version 3.5 model was calibrated and validated for the Aththanagalu Oya catchment and the daily river flow values for the past twenty years (1994-2014) were generated at the pre weir of the Mangalathiriya anicut. The downstream flows were calculated by deducting the drinking water requirements of the anicut. The existing flow regime at the post-weir was subjected to a RVA analysis, while utilizing 32 different hydrological parameters. The RVA targets (set based on the flows of pre weir site) and rate of non-attainment (for the flow at the downstream of the weir of Mangalathiriya anicut) were calculated to evaluate the sufficiency of the downstream flow regime to cater the EF requirements of downstream ecosystems. The rate of non-attainment of the IHA group 1 and group 2 parameters range in between 33 - 100 % suggesting a moderate to severe level of ecological degradation of the downstream ecosystems. In the IHA group 3, inability of calculating the timing of lower limit of annual extreme water condition due to the prevalence of similar minimal flow levels for several days forced the annual minima to be left uncalculated. Yet the annual maxima reflect a rate of non- attainment of 43 %, while the rate of non-attainment of both IHA group 4 and 5, range in between 48 - 100% and 53 - 100 %, respectively suggesting an ecological degradation of moderate to severe degree. Furthermore, the mean rate of non-attainment of 57.15 % predicts an overall moderate degree of ecological degradation of downstream ecosystems due to the operation of the Mangalathiriya anicut of Aththanagalu Oya. Thus, the results of the current study emphasizes that an adequate level of EF regime is not maintained at the downstream of the Mangalathiriya anicut in Aththanagalu Oya in accordance with the RVA.
Fluoride uptake by native and modified cattle bones from aqueous medium by batch adsorption
(University of Peradeniya, Sri Lanka, 2015-11-06) Gunathilake, B.A.P.T.; Iqbal, M.C.M.; Sumanasinghe, V.A.
Fluoride is found in excess compared to the WHO recommended levels in drinking water in the Kandy district. Health hazards such as dental fluorosis, skeletal fluorosis, crippling fluorosis and metabolic defects in lipids, proteins and vitamins are caused due to excess Fin drinking water. Among several defluoridation techniques, adsorption is the most effective and common method. The objective of this study was to investigate the effectiveness of the natural, economically feasible and eco-friendly materials such as plant leaves and cattle bones for removing fluoride ion from drinking water using batch adsorption method. Bio-adsorbent materials were collected and rinsed initially with tap water, and then with deionized water. Cleaned materials were air dried for 48 h and oven dried at for 48 h. Dried materials were sieved to obtain particle size between 250 – 350 μm. Batch adsorption experiments were conducted. A mass of 0.2 g of different adsorbents was added in 50 mL of 3 mg fluoride solution and shaken at 80 rpm in orbital shaker for 3 h. Thereafter, suspension was filtered and final Fconcentration was determined by fluoride ion-selective electrode. Chemical and physical modifications such as base treatment and bone char preparation were done to enhance the adsorption efficacy. Native bones were heated at 500oC for 3 h in muffle furnace to prepare bone char (BC). Effect of contact time and dosage were determined for chemical modification and effect of pH, kinetic studies, isotherm studies, desorption and adsorbent characterization for BC were carried out. adsorption on BC was maximum between pH 4-7 and equilibrium time for BC was 12 h. Pseudo second order kinetic model and Langmuir isotherm model described adsorption of on BC. The highest desorption was given with 0.1 M NaOH. BC enhances the efficacy of defluoridation from aqueous medium and is a cost effective and eco-friendly biosorbent.
Forecasting international tourism income of Sri lanka : trend analysis
(University of Peradeniya, Sri Lanka, 2015-11-06) Konarasinghe, K.M.U.B.
Growth of the tourism industry in Sri Lanka shows the historical development mainly in two ways. That is the growth of tourist arrivals and income. Tourism impacts on the economy of Sri Lanka, which rely heavily on foreign exchange earnings. This has been a general interest of the government. Therefore, the government needs reliable forecasting to cope with uncertain situations and developing sound strategies to maintain the growth of tourism industry. This study was focused on identifying an appropriate trend model for forecasting international tourism income of Sri Lanka. Monthly income data from 2009 to 2013 were obtained from statistical reports of 2012 and 2013 of Sri Lanka Tourism Development Authority (SLTDA). The study concerns the period of post-war, which is after the year 2009. Model fitting was done by utilizing data from January 2009 to April 2012 and data from May 2012 to May 2013 were utilized for model verification. Four trend models were tested with log transformation including one linear and three nonlinear models. Residual plots and Anderson-Darling tests for residuals were used as the model validation criterion. Forecasting ability of the models was assessed by considering Mean Absolute Percentage Error (MAPE), Mean Square Error (MSE) and Mean Absolute Deviation (MAD). Box and whisker plot showed no outliers in the data set. Results revealed that Quadratic Trend Model has least MAPE’s in model fitting and verification: 0.90% and 1.12 %, respectively. MAD and MSE also confirmed the smallest deviation compared with other trend models. Residual plots and Anderson-Darling test confirmed the normality of residuals. Also, residuals Vs fits confirmed the independence of residuals. It was concluded that the Quadratic Trend Model with log transformation is suitable for forecasting international tourism income in Sri Lanka. Monthly income for the period from May 2012 to November 2013 were forecasted by the model and found them close to the actual income. It is recommended to try other time series techniques, namely, decomposition techniques, Auto Regressive Integrated Moving Average (ARIMA) models etc., to capture the seasonal behavior of the series.
Geostatistical mapping of selected soil chemical properties in red latosols of Sri Lanka
(University of Peradeniya, Sri Lanka, 2015-11-06) Eranga, R.L.A.A.; Karunaratne, S.B.; Abeysinghe, D.C.; Gajanayake, B.
Soils are highly variable even at the field scale and detailed studies of spatial variability of soil properties across the landscape are important to manage soils in a sustainable manner. Geostatistics enables to quantify the spatial variability and subsequently prepare detailed digital soil maps. In this study, an attempt was made to quantify the spatial dependence and map the selected soil chemical properties (viz. pH, exchangeable potassium (K) and available phosphorus (P)) in Red Latosols of Sri Lanka. As the study site, a sub set of 22 ha was selected from the cashew seed garden in Elluwankulama, Puttalam District managed by Sri Lanka Cashew Corporation. A design-based sampling scheme namely stratified random sampling was adopted in order to collect soil samples. The stratification was carried out using compact geographic stratification using k-means clustering algorithm and study site was divided in to five strata. Total of 100 sampling locations were sampled where 20 sampling locations were allocated to each stratum. For each considered soil chemical property we deployed a geostatistical approach to create higher resolution digital soils maps and to quantify the spatial distribution of respective soil chemical properties across the study site. The geostatistical models were cross validated and calculated mean error (ME) and root mean square error (RMSE) in order to assess the model quality. Spatial model quality results obtained from the cross validation analysis revealed that, calculated ME values for soil pH (0.002) exchangeable K (0.403 ppm), and available P (0.004 ppm) were closer to zero which suggests unbiased estimation. In case of RMSE, all considered soil chemical properties reported lower values, which includes for soil pH (0.354), exchangeable K (13.581 ppm), and available P (1.673 ppm), respectively suggesting accurate estimation. In analysis of spatial dependence, nugget-to-sill ratio showed strongly structured spatial dependencies with negligible random variations for all considered soil chemical properties. Results further revealed that spatial correlation (range parameter) of pH, exchangeable K and available P reported as 31 m, 98 m and 54 m, respectively. This information is vital to carry out future soil sampling of Red Latosols in order to optimally characterize the spatial variability of considered soil chemical properties by maintaining sampling interval within the estimated range parameter. Furthermore, it was indicated that pH values in most areas of the study site varied from very strongly acidic (4.5) to strongly acidic (5). The exchangeable K and available P levels are mainly distributed within fairly low (58.5-78 ppm) to medium (78-97.5 ppm) and fairly low (7.5-15 ppm) categories, respectively. Maps produced in this study provide valuable information on spatial distribution of considered soil chemical properties including nutrient status within the study site that can be used as a guide to conduct site specific fertilizer applications, intercropping and other management practices, in an environmental friendly manner.
Identification of salinity hazard zones using dualem-1s proximal soil sensor
(University of Peradeniya, Sri Lanka, 2015-11-06) Hiranthika, H.G.K.; Vitharana, U.W.A.; Perera, R.A.C.J.
Development of soil salinity is one of the degradation processes that affects soil productivity throughout the world. It is predicted to aggravate in the coming decades endangering food security. In Sri Lanka, soil salinity occurs in major irrigated inland areas of the dry zone and coastal areas. Information on spatial variability of soil salinity and identification of salinity hazard areas are important to apply relevant reclamation measures, to select suitable crop varieties and to minimize further degradation of productive lands. This study focuses on the potential of DUALEM-1S, an electromagnetic induction-based proximal soil sensor to explore the spatial variability of soil salinity and subsequent delineation of potential salinity hazard zones in dry zone paddy soils. Apparent electrical conductivity survey was performed using the DUALEM-1S sensor in a paddy field (2.5 ha) in Mahailluppallama. Top (0-30 cm) and subsoil (30-60 cm) samples were collected at 35 sample locations those identified using the Latin Hypercube sampling technique based on . Soils were analyzed for pH, EC (1:5 Soil: Water), EC of saturated paste , texture, organic matter (OM), available Na, Ca, Mg, and CEC. The survey resulted in 6318 measurements of horizontal , subsoil sensitive) and perpendicular (, topsoil sensitive) coplanar coil orientations. Both measurements were highly correlated (r = 0.95). The and measurements showed strong correlations with topsoil (r =0.90) and (r=0.89), respectively. The regression model fitted between and (R2 = 0.8) showed that latter can be used as a soft information to predict the salinity hazard of the study area. Two potential salinity hazard zones were delineated using Fuzzy k-means classification based on interpolated map of . One zone was having comparatively low (0.1- 155 mS/m) and the other a higher (155- 309.9 mS/m). Soils were obtained from each zone for further analysis. Soil analyses revealed that the zone having high as a sodic zone (ESP > 90.1 %) and zone having lower as a salinity hazard zone. A pot experiment conducted using soils of potential salinity hazard zones revealed a zero germination of Bg 352 and At 354 rice varieties in the sodic zone and the non saline zone did not affect on the germination of both varieties. This study results justified a strong potential of proximal soil sensing for the characterization of salinity development in paddy soils in the dry zone.
Identifying impact of work life conflict on job satisfaction
(University of Peradeniya, Sri Lanka, 2015-11-06) Lankeshwara, P.
Ceylon Electricity Board (CEB) is a body corporate for electricity undertaking in Sri Lanka. It conducts its massive duties to the Sri Lankan public though Generation, Transmission, Distribution and other services. One of the major problems that the results of pilot survey has revealed is that, among the CEB workforce many of non-executive staff in CEB-Sabaragamuwa are facing problem of work life conflict. At present the conflict between work and family has become a crisis for organizations. With the increase in dual family parents, more job demand and long working hours made it almost impossible to create a balance between work and family. This situation automatically reduces job satisfaction of the employees and then affects the productivity and profitability of the organization. The overall objective of this research was to analyze the factors related to work life conflict and its impact on job satisfaction at the CEB-Sabaragamuwa Provincial Office. The data were collected by distributing a questionnaire and the sample has comprised 120 non-executive employees. Pearson correlation test and Regression analysis were utilized as data analysis techniques. The results revealed that work life conflict impacts on reducing the job satisfaction. Further, family to work conflict could be identified as the most critical predictor. Ultimately work life conflict of non-executive staff employees of CEB negatively impact on their job satisfaction. The relationship between work life conflict and job satisfaction is inversely related to each other.
Impacts of sea level rise and bed level accretion on residence time of Negombo lagoon, Sri Lanka
(University of Peradeniya, Sri Lanka, 2015-11-06) Pushpakumara, P.K.P.; Nandalal, K.D.W.; Weerakoon, S.B.
Water quality of an aquatic system is highly influenced by residence time (RT), which indicates how long a constituent is retained inside the system. This paper focuses on the effect of climate change induced future sea level rise (SLR) and associated bed level variations on RT of Negombo lagoon, Sri Lanka. The hydrodynamic behaviour of the lagoon was numerically simulated using Delft3D surface water modelling suite. The time required to drop the concentration of a constituent to of its original value was calculated as the RT of the lagoon. Anticipated maximum SLR of 79 cm at the end of the 21st century, predicted by the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, was considered as the future sea level of the lagoon. Three bed level accretion conditions, namely, no bed level accretion, accretion of the lagoon bed level by 50% of the SLR (partial bed level accretion condition) and accretion of the lagoon bed level similar to the SLR (full bed level accretion condition), in response to the anticipated SLR were considered. RT was calculated for each bed level variation under low (5.64 ) and high (41.93 ) streamflow conditions. Model predicted RTs of the lagoon at present are 22.4 days and 12.4 days under low and high streamflow conditions, respectively. Under the absence of bed level accretion, RT is increased up to 32.2 days (+43.7%) and 17.8 days (+43.5%) due to SLR in low and high streamflow periods, respectively. Under partial bed level accretion, RT is decreased up to 18.1 days (-19.2%) and 12 days (-3.2%) in low and high streamflow periods, respectively. RT is decreased up to 13.4 days (-40.2%) and 8.5 days (-31.5%), under full bed level accretion, in low and high streamflow periods, respectively. The results reveal that the climate change induced future SLR and the associated bed level accretion influence the RT of the lagoon altering the lagoon water quality.

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