University of Sri Jayewardenepura: Journals & Proceedings
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Effects of Water Soaking Time on Quality and Chemical Composition of Fresh Sticks of Ceylon Cinnamon (Cinnamomum zeylanicum Blume)
Get PDFCeylon cinnamon (Cinnamomum zeylanicum Blume) is a miracle spice exported from Sri Lanka and its quality plays a major role in market growth and retention. Sri Lanka, despite its competitive edge over Ceylon cinnamon, has struggled to capitalize on this due to poor food safety and quality management systems. Sri Lanka's cinnamon farming and processing methods are suboptimal, leading to poor quality. A certification-level factory concept is proposed to address this issue. Fresh cinnamon sticks are collected from rural areas and transported to central factories, resulting in high transportation costs. Therefore, the sticks are collected and stored in tanks underwater for more than one day. Government authorities recommend processing the sticks on the same day of harvesting, albeit there is a lack of scientific evidence to support this requirement. The current study aims to identify potential quality and chemical composition variations from different water storage durations of fresh cinnamon sticks. Eight samples were analyzed: an initial sample (control) with no soaking and seven samples soaked for varying durations, from 1 to 7 days. The comprehensive approach encompasses determining moisture content, oil content, yeast and mold content, water activity, color variation, chemical analysis of oil samples by GC-MS, and the evaluation of the peelability of cinnamon bark. The research aims to provide valuable insights into optimizing post-harvest handling techniques to improve the quality of cinnamon. Most quality parameters, including moisture content, volatile oil content, water activity, total ash, color values, and microbial counts were not significantly affected by soaking. Furthermore, the peelability of cinnamon bark was also unaffected by the length of soaking time. Though the cinnamaldehyde content in the oil has decreased, the exact change is difficult to interpret due to the semi-quantitative nature of the analysis. Moreover, an increase in 3-phenyl-2-propen-1-ol was also detected in GC-MS analysis. Further analysis and replication of the experiments are underway to establish sound recommendations based on chemical composition of cinnamon bark.
Keywords: Ceylon cinnamon, Cinnamaldehyde, Quality management, Chemical composition, GC-MS analysis
 
Oryza nivara Identified in Wilpattu National Park
Get PDFOryza nivara is a wild rice species primarily distributed in the dry and intermediate zones in Sri Lanka and also reported from Wilpattu National Park (WNP). This is a good food source for most of the wild animals including elephants. With the long term aim of enhancing O. nivara populations in their native habitats as a food source for wild animals, we conducted a survey to identify O. nivara populations in WNP and further we studied their ecology and composition. During the study, we identified three O. nivara populations within WNP; Kumburaviya, Pallekandal, and Ilandamote tank. Soil samples and rice plants were collected from these locations and associated species were recorded. Soil pH, salinity and total dissolved solids (TDS) were measured. Gross energy, dry weight, crude protein, fat and fiber contents of collected O. nivara plant samples were measured with standard methods. In Kumburaviya, the distribution and density of this species were 41% and 14.6 m², respectively, whereas in Pallekandal, those were 16% and 4.4 m², respectively. Samples were not collected from the Ilandamote tank due to the low plant density. According to our observations, this species was primarily found in marshy areas with acidic soils (mean pH 5.2) and low soil salinity (0.1%). The mean nitrate-nitrogen and phosphorus contents in the collected soil samples were 31.865 ppm and 38.15 ppm, respectively. The mean soil conductivity was 160.85 µS/cm, and the mean TDS was 75.5 mg/kg. O. nivara coexists with several other plant species, including Hygrophila schulli, Eleocharis dulcis, Echinochloa crus-galli, Eichonia crassipes, Calotropis gigantean, Limonia acidissima and Commelina diffusa. Considering the entire plant of O. nivara, the mean dry matter percentage was 31.75%. The mean values for gross energy, ash, crude protein, fat (ether extract), and crude fiber content were 3,578.6 kcal/kg, 18.6%, 6.2%, 1.42%, and 35.25%, respectively, on a dry matter basis. Our study found that O. nivara is a suitable energy source compared to most wild and hybrid grass species. Although its crude protein content is lower than that of hybrid grasses, it is within the range of most wild grass species. Further, the ash content is higher than that of hybrid grasses, due to its high crude fiber content. This study evaluates Oryza nivara's potential in habitat enrichment projects for supporting wild rice species and mitigating human-elephant conflict. It highlights the importance of soil quality assessments and provides baseline scientific data on O. nivara in WNP.
Keywords: Oriza nivara, Locations, Nutrition, Distribution, Soil  
Effects of Soil Type and Moisture on the Pupation Behaviour and Emergence of Heortia vitessoides (Lepidoptera: Crambidae)
Get PDFHeortia vitessoides belongs to Crambidae: Lepidoptera, is the major defoliator of Aquilaria species, significantly lowering agarwood resin production due to partial or complete defoliation. This infestation has led to severe economic losses in several countries, including Sri Lanka. The larval instars of H. vitessoides feed gregariously and voraciously on Aquilaria leaves. Upon maturation, the larvae pupate in the soil which is an essential step in their life cycle. Identifying factors essential for the pupation process is crucial to understand their pupation behaviour, which has not been studied in Sri Lanka, despite the substantial impact of H. vitessoides on Aquilaria tree growth. This study aimed to identify the effect of substrate type and moisture content on the pupation behaviour and to study various stages of its life cycle. First, the saturation level preferred by larvae to pupate in their natural conditions was estimated. No choice tests were conducted using sandy clay loam, clay loam and sandy loam soils under five saturation levels (0%, 25%, 50%, 75% and 100%) with fifth larval instars under controlled conditions in the laboratory. Various stages of life cycle, burrowing and emerging rates were recorded. The experiment was replicated. The study revealed that it takes approximately two days for the fifth instar larvae of H. vitessoides to burrow into the soil for pupation. Adult emergence occurred 13 days after the start of burrowing. The adult moths had a lifespan of about seven days after their emergence. There is a significant effect of soil saturation level and soil type on burrowing and emergence rates, with a significant interaction between these factors. Larvae successfully burrowed into the 25% and 75% saturated substrates in all three soil types, but the emergence rates were significantly very low. In all three substrate types, extremely wet (100%) and extremely dry (0%) saturated substrate resulted in the significantly lowest borrowing rates with zero emergence. Sandy clay loam saturated with 50% was mostly preferred for burrowing and emerging of H. vitessoides, aligning with the natural pupation conditions of H. vitessoides. This study provides insights into the pupation ecology of H. vitessoides, aiding in the development of effective control measures through soil treatment techniques.
Keywords: Heortia vitessoides, Aquilaria, Pupation, Emergence, Saturation leve
Spatial Variability of Soil Organic Carbon and Nutrient Dynamics in Disturbed and Undisturbed Riverine Mangrove Sites in Mannar
No full textThe reclamation of coastal blue carbon ecosystems for agricultural or industrial land uses has resulted in declination of soil carbon storage. These disruptions to riverine mangroves in the Mannar region were location-specific and varied in intensity. This study examines soil spatial variability in soil organic carbon (SOC) and nutrient availability due to disturbances in riverine mangrove sites in the Mannar region. It identifies an inland strip of mangroves at Mendakal Aru, Methanvely near Kalimondai beach, and Achchankulum, revealing spawning activities, water flow diversion, and exploitation at the top two sites. Random soil sampling and analysis to examine the variation of SOC, carbon fractions, and nutrient contents at the upper soil layer of 0-15 cm were conducted at disturbed mangrove sites (n=19) at Methanvely and Mendakal Aru and were compared with the undisturbed sites (n=3) at Achchankulam. Three clusters were identified following principal component analysis and cluster analysis, with one cluster having the highest concentrations of phosphorous and manganese (58.3±9.4 mg kg-1; 86.6±32.4 mg kg-1), while the other two clusters had the highest SOC, sodium, and zinc concentrations (3.12±0.44 %; 10.3 g kg-1; 49.5±49.5 mg kg-1) and lowest contents of SOC and permanganate oxidizable carbon (0.68±0.28 %; 296.3±152.2 mg kg-1). A mixed model ANOVA was used to determine the significance of the sites and vegetation communities. Accordingly, Achchankulam had significantly (P<0.05) higher concentrations of SOC and ammonium (2.2±0.5% and 25.0±4.3 mg kg-1) yet the lowest calcium concentration (3.1×103±9.1×103 mg kg-1) compared to disturbed riverine mangroves. SOC were low as 0.97%±0.25 and 0.97%±0.20 at Mendakal Aru and Methanvely, respectively. Mendakal Aru was found with the lowest ammonium levels (0.5±2.1 mg kg-1), while Methanvely had the highest calcium content (18.1×103±4.0×103 mg kg-1) and pH (8.4±0.2). Thus, the vegetation communities alone did not have a notable variability in SOC, yet significant variability was caused at specific sites. The study reveals an underline correlation of high SOC and ammonium levels and lower calcium concentrations. Significant variations exist in SOC and nutrients between disturbed and undisturbed riverine mangrove areas in the region. The findings emphasize the need for site specific management for recovering the disturbed coastal ecosystems.
Keywords: Blue carbon sequestration, Cluster analysis, Gulf of Mannar, Mangrove ecosystem Disturbance, Principal component analysi
Evaluation of Water Quality and Heavy Metal Pollution in Selected Wetlands in Colombo District
No full textWetland ecosystem in Colombo District is facing increasing heavy metal accumulation, posing risks to the environment and human health. The present study aimed to assess the quality in the water and concentrations of heavy metals in the water of five wetlands located in the Colombo District, namely Kotte, Madinnagoda, Heen Ela, Diyasaru Park, and Gothatuwa.The research involved collecting water from different locations within these wetlands during rain free period in 2023. The concentrations of heavy metals were analyzed using Inductive Couple Plasma-Mass Spectrometry (ICP-MS). Physio-chemical parameters of the water, including pH, temperature, electrical conductivity (EC), salinity, dissolved oxygen (DO), and total dissolved solids (TDS), were measured. The pH levels of water ranged from (6.20±0.00) and (7.23±0.06), all within safe limits of 6.0-8.5.DO levels varied between (0.03±0.00mg/L) and (8.43±0.06 mg/L) were not within the recommended level of 6.5- 8 mg/L in all the wetland except Diyasaru Park. Salinity levels across the wetland locations ranged from (0.10±0.01%) and (0.31±0.00%) at all wetlands were above the maximum limit of 0.60%. EC levels were between (187.67±1.53 μS/cm) and (642.33±2.52 μS/cm), below the maximum limit of 400 μS/cm at all locations except at Gothatuwa and Madinnagoda. TDS varied from between (110.80±0.72mg/l) and (311.50±0.76mg/l), met the maximum limits of 300 mg/except of Madinnagoda wetland. Water samples collected from the wetlands showed an accumulation of heavy metals. Metal accumulation varied among wetland locations. The Fe concentrations were consistently higher than those of other heavy metals across all wetland locations. The concentrations of Fe ranged from (0.2367±0.0042 mg/l) to (0.9262±0.0041 mg/l), Ni ranged from (0.0414±0.001 mg/l) to (0.1024±0.0016 mg/l), and Pb ranged from (0.0056±0.0002 mg/l) to (1.2948±0.004 mg/l), with all three frequently exceeded the established drinking water standards. These findings raise concerns about the potential health risks associated with heavy metal contamination in the Colombo wetland ecosystems.
Keywords: Heavy metals, Wetland ecosystems, Water quality, Physio-chemical parameters, Human health
 
First Insights into the Floristic Community, Faunal and Macro-Fungal Richness of Diyagama Forest, Homagama, Colombo District
No full textUrban forest patches provide numerous environmental benefits. Diyagama forest (8.9 ha) is the only forest patch in the suburbs of Homagama which is left aside after recent infrastructure developments. For the first time we describe its biodiversity with special emphasis on floristics. Sampling was conducted in July 2024 for flora and from April-October 2024 for fauna and macro-fungi. Inventories of flora, fauna and macro-fungi were prepared. Ten 100 m2 plots were located in pairs in five locations in the forest, and the tree height, diameter at breast height (DBH), and number of individuals in understory were recorded. Plant cover of undergrowth was estimated using Braun – Blanquet scale. Temperature, relative humidity, and light intensity were measured at three random points in each plot. Plant life form was analyzed, ecological dominance of canopy trees was determined using the importance value (IVI). Variations in forest plant community were determined by Bray-Curtis similarity index of hierarchical clustering method using SPSS Statistics. The temperature, relative humidity, and light intensity across all forest plots reported average values of 31.8°C, 80.94%, and 9413.31 lux respectively. The trees reached approximately 10m height in the canopy. Endemism was 12.6% for flora and 11.58% for fauna. The biological richness included 96 plant species belonging to 51 families and 87 genera of which 12.6% were threatened (8 vulnerable and 3 endangered). Only 12 were exotic species. The macro fungal richness was 48. Among the 72 bird species, 5 were threatened species (with 2 critically endangered). Out of 29 reptile species one species was in the threatened category. Amphibian richness included 7 species, while richness of fish species was 15 with 4 being threatened. Butterfly diversity was notable with 52 species, 3 of which are threatened. The site hosts 16 mammal species, including 5 threatened species. The canopy tree density was low (8.7/100m2) whereas the dense understory had 58.6 individuals/100m2. Due to shade undergrowth was scanty but had 36 individuals/100m2. The dominant plant life form was trees (80.85%) of DBH range of 33-53cm. Higher IVI values were exhibited by Alstonia macrophylla (51%), Horsfieldia iryaghedhi (39.8%) and Lannea coromandelica (39.3%) reflecting their ecological dominance in the forest community. Invasive alien shrub and herb species were restricted to forest edges and absent inside. The sample plots separated with<25% dissimilarity indicating an even community structure across the forest. Nevertheless, it offered a variety of microhabitats for many fauna and macro-fungi. As a biologically wealthy forest patch at mid-successional stage of regeneration, its conservation efforts should focus on controlling the spread of invasive species, prevention of road kills of fauna, protecting the remaining large trees against illegal exploitation and promoting natural regeneration with least disturbance in order to maximize its ecosystem services.
Keywords: Diyagama Forest, Plant community, Fauna, Macro- fung
Mathematical Model for Forecasting Sawn Timber Valuation: A Case Study of Jack Tree in the State Timber Co-orporation, Sri Lanka
No full textTimber is the most valuable commercial commodity taken from most forests. There is growing pressure on the timber industry to increase efficiency and sustainability. The State Timber Corporation (STC) currently functions as the sole authority in harvesting trees from state lands in Sri Lanka. They received permitted logged areas mainly from the forest department in Sri Lanka. STC converts a significant amount of timber to sawn timber that is cut from logs into different shapes and sizes, among their other functions. The output sawn timber volume is estimated by using only the measurable values named length, and girth of the log given in the table (standard) which they have before the sawn timber production by STC. After the sawn timber production, the real sawn timber volume will not reach estimated sawn timber value due to several reasons such as natural inconsistencies, high processing waste, frequent defects, etc. Therefore, this study aims to find a mathematical model to predict the actual sawn timber valuation of a log using the above variables. This study was done based on the Jack tree sample and relevant data for the study was collected from the STC, in Sri Lanka. There were 152 data records. Initially, the sawn timber valuation was estimated by using the multiple linear regression model (MLR) which is a statistical technique. It calculates the linear relationship between independent variables and output variables. But the MLR model is unable to find the nonlinear relationship between inputs and output if there is one. Therefore, accuracy of the MLR model was limited. Then the gradient boosting method (GBM) was applied to the results of the MLR model to increase the accuracy of the model. The learning rate and number of trees were selected as optimal values to avoid overfitting and to balance the accuracy respectively for the GB model based on mean square error. The model accuracy was increased by 70%-90%. The results demonstrated that GBM significantly enhanced prediction accuracy, with its estimates closely aligning with actual production values. I.e. developed mathematical models are better than traditional methods. The actual sawn timber volume, which is received as a final output of the timber processing, is the crucial factor in determining the efficiency and economic variability of the wood processing operation. This model can be applied to any kind of tree and accuracy of the model can be enhanced by incorporating more input variables.
Keywords: Forecasting, Gradient boosting method, Multiple linear regression, Sawn timbe
Investigating the Relationship between CO2 Emissions, Renewable Energy Generation and Forest Coverage Using the ARDL Approach
No full textRenewable energy, combined with increased forest coverage, is increasingly identified as a key solution to address environmental pollution via CO2 emissions, and the energy crisis in Sri Lanka. Therefore, this study aims to reveal the relationships of CO2 emissions (Mt CO2-eq), renewable energy generation (GWh) and forest coverage in Sri Lanka. Data on annual CO2 emissions, renewable energy generation and forest area as a percentage of land area were obtained from the World Bank comprehensive data, Climate Watch data and the Ceylon Electricity Board. The period under consideration was from 1990 to 2021. The Auto Regressive Distributed Lag (ARDL) approach to cointegration is employed for the analysis of data. Error correction model and Granger Causality test are also applied subsequently. The relationships between the variables were estimated using the ARDL (2,2,1) model. According to the results of the ARDL Bounds testing, CO2 emissions, renewable energy generation and forest area are in a long-run equilibrium relationship. The model was found to be stable and satisfies all the requirements related to diagnostic tests, including tests for serial correlation, normality, and heteroscedasticity. The lagged CO2 emissions significantly contribute to current CO2 levels while the hydroelectric power production and the lagged values of forest coverage exhibit a notable impact on CO2 emissions, emphasizing their importance in determining the atmospheric CO2 concentration in the long run. In the short run, there is a significant impact from hydroelectric power generation. The coefficient of the Error Correction Term (ECT) is negative and statistically significant, revealing that approximately 9.26% of the disequilibrium in CO2 emissions converges back to the long-term equilibrium within a year. The Granger causality test results reveal that unidirectional causality exists from renewable energy generation and forest cover towards CO2 emissions in Sri Lanka. These insights provide valuable guidance for policymakers in developing strategies that expand renewable energy generation and lead to forestry initiatives to promote environmental sustainability in Sri Lanka.
Keywords: CO2 emissions, Renewable energy generation, Forest coverage, ARDL methodology, Error correction mode
Case Study of Application of the Polluter Pays Principle, on a Digital Platform for the Management of Sanitary and Biomedical Waste Generated at the Household Level
No full textThe generation of household-level sanitary and clinical waste has grown significantly due to population growth, changing consumer habits, and rising living standards. Mismanagement of such waste poses critical threats to human health and the environment, with urban areas facing amplified challenges due to limited living space and inadequate disposal options. Addressing this, Sisili Hanaro Encare launched Sri Lanka’s first door-to-door hazardous waste management program in 2023, targeting household-level waste across Colombo, Gampaha, Galle, Kalutara, and Kandy districts. The program, serving 3,238 customers, offers comprehensive waste management services, including collection, transportation, and advanced incineration-based disposal, operating under the polluter-pays principle with fees determined by waste volume. QR-coded bags and a digital platform enhance tracking and operational efficiency. A survey conducted in collaboration with the students from the University of Sri Jayewardenepura assessed the program’s effectiveness using a geographically diverse sample of 60 households. Participants included 36% housewives, 34% private employees, 22% government employees, 5% retirees, and 3% self-employed individuals. Key waste categories included baby diapers (57%), adult diapers (17%), and sanitary napkins (19%), with 7% of households generating biomedical waste, such as insulin-related remnants. Before adopting the Encare program, 47% practiced open burning, 20% buried waste, and 28% relied on local authorities. Despite awareness of health (88%) and environmental (85%) risks, indirect disposal costs averaged Rs. 837.5 monthly, arising from practices like fly-tipping and fuel for open burning. Motivations for joining the Encare program included hassle-free services (43%), eco-friendly practices (27%), and confidence in proper waste disposal (13%). The survey found 90% of respondents satisfied with the program’s costs and value, with 92% praising its efficiency and 100% recommending it. Additionally, 98% preferred male staff for waste collection. The program demonstrated significant environmental benefits, notably reducing air pollution by 40,000 Air Emission Factor (µg TEQ/t), as per UNEP’s dioxin toolkit, by shifting from open burning to advanced incineration. These findings highlight the program’s effectiveness in addressing public health and environmental concerns while ensuring high customer satisfaction. Encare's scalable model offers a promising solution to urban waste management challenges, emphasizing its potential to transform hazardous household waste disposal practices in Sri Lanka.
Keywords: Infectious, Volume base, Incineration, Willingness to Pay, Digital flatform, Realtime tracking, Extended Producer Responsibility. 
The Impact of Games on Citizens' Awareness and Behavioral Change Regarding Decarbonization
No full textAs the importance of addressing global warming and reducing carbon dioxide emissions grows, achieving carbon neutrality requires not only corporate efforts but also a shift in awareness and behavioral changes at the citizen level. However, awareness of environmental issues among citizens, including younger generations, remains low, and practical actions are lacking. Therefore, effective approaches to promote decarbonization behavior among citizens are needed. This study aims to propose and evaluate the effectiveness of a new approach to foster changes in awareness and behavior toward environmental issues, particularly among younger citizens, through a quiz-style computer game. The game, which presents quizzes related to decarbonization and ranks players based on their accuracy, was developed alongside the creation of the decarbonization-related quiz content for the game. In 2023, a monitor survey and a post-experience questionnaire survey were conducted during the Toyo University Akabanedai University Festival to evaluate the effectiveness of the developed game (n=168). Additionally, two rounds of online surveys were conducted in February and March 2024 to assess trends in citizens' awareness and behavior regarding decarbonization (n=10,500). The results of the monitor survey showed a significant increase in environmental awareness among participants in their teens and twenties, with their willingness to engage in environmentally conscious actions increasing approximately threefold. Furthermore, nearly 90% of participants reported gaining new environmental knowledge through the game. These findings suggest that quiz-style games can be an effective means of improving awareness and behavior regarding environmental issues. A cluster analysis of the online survey results classified respondents into four groups based on their awareness and behavior. The findings particularly suggest that a targeted approach would be effective for those in the group with moderate awareness and low activity levels. Future plans include conducting follow-up surveys, including monitor surveys, to assess the long-term effects of the game and further improve its content.
Keywords: Decarbonization, Environmental awareness, Behavioral change, Gamification, cluster analysi