University of Sri Jayewardenepura: Journals & Proceedings
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Assessing the Human Monkey Conflict in Bulathsinhala Divisional Secretariat in Kalutara District, Sri Lanka
No full textIn Sri Lanka, Human Monkey Conflict (HMC) is a growing issue mainly due to habitat loss caused by urbanization, agricultural expansion and human population. This study assessed the level of impact on humans and the aggressiveness of precautionary actions taken by households in eight Grama Niladari Divisions (GND) in Bulathsinhala Divisional Secretariat (BDS). These GND were selected based on existing literature and records from the BDS office, related to HMC. Accordingly, Ihala Naragala, Bulathsinhala-South, and Kongasthenna were recorded as not-affected divisions; Polegoda-West, Molkawa, Pahala Kudaligama, Ihala Naragala-South, and Delmella GND as affected divisions. The current situation of HMC was assessed by conducting semi-structured interviews with 100 households across those GND. It underlines the presence of two species, Toque macaque (Macaca sinica) and Purple-faced langur (Semnopithecus vetulus), while Toque macaque is the most dominant species which are causing substantial damage to crop and infrastructure and translates into economic losses. The impact level of the HMC was identified as highly affected, moderately affected, less affected, and not affected based on three criteria: the frequency of monkey visits, monthly economic loss, and negative impacts on properties and lives, such as crop, food, and material loss, attack household, infrastructure and roof damage, and physical injuries to humans. The precautionary actions were categorized based on their aggressiveness: extremely aggressive (resulting in monkey deaths), very aggressive (causing severe physical injuries), moderately aggressive (causing minor physical injuries), and less aggressive (causing no physical injuries) chasing monkeys away. According to the qualitative analysis, monkeys have been visiting Kongasthenna and Bulathsinhala-South occasionally and identified as non-affected GND. Monkeys visited less affected GND such as Delmella, Ihala Naragala, and Molkawa monthly. Polegoda-west was identified as moderately affected and 30% of the interviewees experienced daily visits, 60% experienced weekly visits by monkeys and 75% households had an economic loss between Rs.5,000.00-10,000.00. The highly affected GND were Pahala Kudaligama and Ihala Naragala-South with 70% and 25% daily visits respectively while a cumulative percentage of 60% households experienced an economic loss over Rs.10,000.00. Extreme and very aggressive precautionary actions could be observed in highly and moderately affected areas. As the conflict intensifies, residents adopt more extreme measures to protect their belongings from monkeys. As mitigation measures for HMC in BDS, the use of non-lethal deterrents such as high frequency noise and visual deterrents, community awareness programs, crop alterations and habitat management plans can be proposed.
Keywords: Human-monkey Conflict, Toque macaque, Purple-faced langur, Affected levels, Aggressive level
Assessing Greenhouse Gas Emissions in PET Recycling: A Case Study of Flake and Yarn Production in Sri Lanka
No full textPolyethylene terephthalate (PET) is one of the most widely used types of plastic globally, particularly in the beverages, cosmetics, and apparel industries. Extensive PET usage poses a risk of plastic waste accumulation and contributes to plastic pollution. The plastic recycling industry plays a critical role in mitigating these impacts, although recycling is energy intensive. This study evaluates greenhouse gas (GHG) emissions associated with PET recycling processes. The study was conducted at a larger recycling facility in Sri Lanka. The analysis encompasses three key stages of the recycling process: (1) collection and transportation of consumed PET bottles, (2) production of PET flakes through washing and processing, and (3) conversion of flakes into recycled polyester yarn. Primary data was collected from company records for two plants for the year 2023 to calculate emissions and assess the resourced utilization. The carbon footprint of polyester yarn was determined using the Intergovernmental Panel on Climate Change (IPCC) methodology. Emissions were calculated for the production of recycled PET flakes from post-consumer bottles and their subsequent conversion into polyester yarn. The results indicate that, on average 249±36.65 tons of PET bottles were collected monthly, producing 195.29±40.84 tons of PET flakes and 139.83±46.22 tons of polyester yarn. The total GHG emissions of polyester yarn production was 281.32±72.98 tons of CO2e monthly, with an average of 2.58±0.49 kg of CO2e emitted per kg of yarn produced. Electricity plays a major role in emissions, contributing 98% during the flake-to-yarn conversion process and 70% during the bottle-to-flake conversion. Reducing emissions from electricity use is challenging without a shift to renewable energy sources. The study highlights potential strategies to reduce emissions from fuel consumption, transportation activities, water use, and waste generation. Strategies such as adopting biomass boilers, optimizing transport routes, and implementing rainwater harvesting and water reuse can enhance the sustainability of PET recycling into textiles.
Keywords: Polyethylene terephthalate, Recycling, Polyester yarns, Greenhouse ga
Distribution of the Critically Endangered Mucuna gigantea (Willd.) Dc. (Fabaceae) in Bentota River, Southwestern Sri Lanka
Get PDFMucuna gigantea (S: Kana-Pus-Wela; E: Elephant Cowitch) is a woody climbing legume vine. It can grow up to 8-15 m long and is about 10 cm in diameter. M. gigantea is distributed in tropical countries including East Africa, India, the Pacific Oceans, Australia, and the Pacific Islands. They occupy mostly bushland, forest edges, riverine and coastal moist forests, coastal scrub, and riverbanks. In Sri Lanka, it was first recorded in Batticaloa in 1849, then re-recorded in 2021, after 172 years in the Madampawila Wildlife Sanctuary in Galle. It has been classified as a critically endangered plant species by the 2007, 2012, and 2020 national red lists. In Sri Lanka, its population has never been studied. The main objective of this study is to discuss the distribution and abundance of M. gigantea in the Bentota River. Randomly laid five hundred-meter-long transects were deployed to investigate the distribution and abundance of M. gigantea in the Bentota River covering a total of 10.7 km. Surveys were conducted by riding boats in the river and walking inside the mangrove. The number of plants and the geo-coordinates were recorded whenever a plant was found. Other species that are co-occurring with M. gigantea were also recorded. Moreover, threats to the plant were recorded during the study. At the same time specimens with reproductive and vegetative parts were collected on the 6th of March 2023 and made into herbarium specimens and deposited in the National Herbarium in Peradeniya. A total of 13 locations with M. gigantea were recorded along the Bentota River. They have grown as mangrove associates in the ecosystem and were recorded grown with Rhizophora apiculata, Bruguiera gymnorrhiza, and Terminalia catappa. Several largely grown plants were recorded from this ecosystem. This is the first time that the plant has been recorded from the Bentota River. Although this is not a viviparous plant species, it has adapted to extreme conditions. Several floating seeds of M. gigantea were observed that can be distributed through tidal flushing. Being a critically endangered plant, it is facing numerous threats viz., illegal encroachment, cutting them for settlements, and clearing them due to blocking the river view. Lack of awareness of people and lack of studies on this plant in Sri Lanka were identified as the major threats. Therefore, it is recommended that appropriate conservation measures be taken to protect this critically endangered plant in Sri Lanka.
Keywords: Bentota River, Critically endangered, Distribution, Mucuna gigante
Seed Priming Methods to Break Seed Dormancy and Enhance Seed Germination in Selected Underutilized Crop and Fruit Species in Sri Lanka
Get PDFMany cultivated crops and fruit species worldwide remain underutilized, despite their potential to enhance food security, nutrition, health, and income generation. Poor germination rates, coupled with prolonged dormancy, may contribute to their infrequent cultivation. Therefore, studying treatments to break seed dormancy and enhance germination is essential. In this study, we examined the seed viability [using 1% Tetrazolium chloride (TTC)], water imbibition, seed germination (in distilled water and in 5% saline solution) and priming of Antidesma bunius, Averrhoa bilimbi, Canavalia ensiformis, Coccinia grandis, Cordia dichotoma, Ipomoea alba, Momordica denudata, Sauropus androgynus and Solanum violaceum. For each species in each treatment, we used 100 seeds in total, with 20 seeds per replicate (n=5), and observed 36 days under optimum light and dark conditions. Water imbibition was measured for batches of 10 seeds in 5 replicates. We employed several seed priming methods: manual scarification (MS), acid scarification (AS) (dipping in 98% H₂SO₄ for 2 minutes), and treatment with a 500 ppm gibberellic acid (GA₃) solution, following standard protocols. The results of the TTC test showed that all species exhibited over 80% viability. The highest imbibition was observed in C. ensiformis when immersed in both distilled water and in saline solution (4.21 g and 2.45 g respectively), while C. dichotoma (0%) did not imbibe water in either distilled water or saline solution. Averrhoa bilimbi produces recalcitrant seeds but the rest of the species possess dormant seeds. Manual scarification of A. bunius and C. dichotoma (p=0.001) and AS of S. violaceum (p=0.001) enhanced their seed germination, but only up to 50%. In contrast, MS significantly enhanced the germination of M. denudate (p<0.001) and I. alba (p=0.004) while significantly reducing the time taken for their germination (p=0.001 and p=0.007). Application of GA3 solution significantly decreased the time taken for the germination in C. ensiformis, C. grandis, S. androgynus, S. violaceum, and I. alba (p=0.001). Further, the GA3 treatment resulted in 100% germination of C. ensiformis, S. androgynus, and I. alba seeds, while 80% seed germination in C. grandis. In contrast, A. bilimbi did not respond to any of the tested seed priming methods. Enhancing seed germination of A. bunius, C. dichotoma, C. grandis, M. denudate and S. violaceum can encourage farmers to cultivate these species, thereby positively contributing to the country’s food and nutritional security, in line with the United Nation’s Sustainable Development Goals. The study also suggests the necessity of exploring seed priming methods for other underutilized crop and fruit species of the country.
Keywords: Gibberellic acid, Acid scarification, Manual scarification, Viability test, Imbibitio
Assessing Biodiversity Conservation through EUDR Compliant Rubber Cultivation in Sri Lanka: A Case Study of Ingiriya Rubber Estates
No full textDeforestation and habitat destruction are among the most critical global environmental challenges, leading to significant loss of biodiversity. In response to these issues, the European Union Deforestation Regulation (EUDR), enacted in 2023, seeks to mitigate deforestation associated with agricultural expansion by ensuring that products entering the EU market are not grown or raised on land that was subject to deforestation. The regulation applies to seven commodities: cattle, cocoa, coffee, oil palm, rubber, soya, wood, and their derivative products. This study investigates the implications of the EUDR for biodiversity conservation within rubber plantations in Sri Lanka. The study was conducted in August 2024 at a rubber estate located in Ingiriya, Poruwadanda, Sri Lanka, which operates in compliance with the EUDR. The study site is bordered on one side by the Mawak Oya River, and the habitat types identified within the area include forest patches, rubber plantations and grasslands. The total study area encompassed 6 acres of rubber state. This comprehensive approach aimed to provide an in-depth understanding of the local biodiversity present within the estate. Species were systematically identified within rubber plantations, and its surrounding habitats utilizing a combination of random sampling, visual observations, and opportunistic methods. A total of 57 faunal species were recorded during the survey comprising 45 species of vertebrates distributed across five taxonomic classes (mammalia, avian, amphibian, reptiles and fish) and 12 invertebrates species belonging to two class Lepidoptera (6) and Odonates (6) were documented. Vertebrate species included representatives from various orders Anura (4), Squamata (11), Testudines (1), Passeriformes (3), Psittaciformes (4), Accipitriformes (1), Columbiformes (1), Piciformes (2), Suliformes (1), Primates (1), Artiodactyla (1), Chiroptera (1), Carnivorac (1), Rodentia (1), Lagomorpha (1), Cypriniformes (6), Synbranchiformes (1), Siluriformes (1), Cyprinodontiformes (1), Anabantiformes (1), and Beloniformes (1). The baseline data generated during the period provides an idea about various species present in the area. Notable observations included the presence of the vulnerable endemic fish species (Pethia nigrofasciata) and the endemic bird species (Loriculus beryllinus), both of which were found in robust populations within the study area. The results of this study indicate that implementing rubber cultivation practices in accordance with the EUDR may effectively safeguard biodiversity by preventing further deforestation, habitat fragmentation and ensuring the conservation of adjacent ecosystems. Specific EUDR practices implemented include, geolocation mapping, chain of custody documentation, restricting rubber cultivation to previously cleared agricultural lands, maintaining buffer zones, and conducting regular monitoring for deforestation. This study recommended future research is necessary to explore long-term ecological outcomes and investigate the adaptability of these practices over the time.
Keywords: Biodiversity conservation, Deforestation, EUDR, Rubber cultivation, Sri Lank
Studying of Underutilized Parts Produced in Processing of Cinnamomum zeylanicum Cultivated in Sri Lanka by Analyzing their Chemical Composition
No full textCinnamon, (Cinnamomum zeylanicum) is widely recognized as a major spice, flavoring agent, and herb consumed globally. This study aimed to identify and quantify the primary chemical constituents of essential oils, the oleoresin content, and the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity of oleoresins obtained from different underutilized parts of Ceylon cinnamon. The underutilized parts used in this study included cinnamon scrapes (obtained from cleaning the outer corky tissue layer of the sticks), 'kathurupodi' (broken pieces and splits of all grades of cinnamon quills), heavy bark (over-matured bark), and 'katta' (scraped from the greenish-brown, mature bark, primarily from upper branches). Essential oil was extracted by hydro distillation using a Clevenger apparatus. The essential oil percentage of each part was calculated, and the dried essential oil samples were qualitatively and quantitatively analyzed through GC-MS analysis. Oleoresins were extracted from each part using Soxhlet extraction, and their antioxidant activity was determined by DPPH radical scavenging activity. The highest essential oil percentage (1.5±0.10 %) was recorded from the 'kathurupodi' sample and a neglectable amount of essential oil was recorded from the cinnamon scrapes sample. Cinnamaldehyde, D-limonene, linalool, α-Phellandrene, Cinnamyl alcohol and eugenol were the main components of the essential oil as identified. The highest cinnamaldehyde content (82.10%) was found in essential oil extracted from the ‘Kathurupodi’ sample. The highest eugenol content (9%) was detected in essential oil extracted from the “katta” sample while there is a lower cinnamaldehyde content (66.78%) when comparing with others. The highest oleoresin percentage (11.19±0.02 %) and DPPH radical scavenging activity, 71.980±2.080 (IC50 value-mg/ml) also have been recorded from “Kathurupodi” sample and the lowest oleoresin percentage (2.22±0.01%) and DPPH radical scavenging activity, 10.910±0.830 (IC50 value-mg/ml) has been recorded from scrapes sample. It can be concluded that ‘Kathurupodi’ has the highest value for those quality parameters among other underutilized parts and mostly those values are close to cinnamon quills. There are significant oleoresins percentages and antioxidant activities for heavy bark and “Katta” samples also with significant profiles of bio active compounds in essential oil including cinnamaldehyde, eugenol, and linalool, which contribute to the characteristic flavor and other significant properties of cinnamon.
Keywords: Cinnamon, Essential oil, Oleoresins, Underutilized part
Developing Eco-Friendly ABS Composites with Naphthoylated Microcrystalline Cellulose: Advancing Green Materials for Industrial Applications
No full textMicrocrystalline cellulose (MCC), a sustainable and renewable material, holds significant potential for advancing green technologies in environmental engineering. This research focuses on improving the mechanical properties of acrylonitrile butadiene styrene (ABS) polymer through the development of ABS-MCC composites, which can offer more eco-friendly alternatives for industrial applications. To overcome MCC’s inherent hydrophilicity and enhance its compatibility with the hydrophobic ABS matrix, MCC was functionalized via naphthoylation, using aqueous 7% NaOH and 12% urea to facilitate the reaction. Results of Fourier-transform infrared spectroscopy (FTIR) and UV-visible spectrophotometry indicate naphthoyl group functionalization, with key FTIR bands at 1,669 cm⁻¹ (carbonyl stretching) and 1,568 cm⁻¹ (naphthalene C-H axial deformation). Contact angle measurements further confirm a reduction in hydrophilicity due to the naphthoyl group functionalization. The modified MCC was incorporated into ABS using melt blending, followed by compression molding to create composite sheets. Samples with varying modified-MCC loadings (1%, 3%, and 5%) were prepared to evaluate their mechanical performance. Shore D hardness tests showed a significant improvement in hardness compared to both pure ABS and non-functionalized MCC composites. The 5% functionalized MCC composite exhibited the highest hardness, attributed to enhanced interfacial adhesion between MCC and ABS, driven by π-π stacking interactions between the naphthoyl groups of modified-MCC and the styrene units in ABS. This research demonstrates that functionalized MCC can significantly enhance the performance of ABS composites, presenting a sustainable alternative for sectors such as automotive and construction. From an environmental engineering perspective, these composites reduce reliance on non-renewable resources, support the development of green materials, and have the potential to minimize the environmental impact of industrial manufacturing processes. Future work will explore additional mechanical properties, environmental impact assessments, and scalability for broader industrial adoption.
Keywords: Microcrystalline cellulose, Acrylonitrile butadiene styrene, Sustainable materials, Polymer composites, Environmental engineerin
An Analysis of Temporal Changes of Human Comfort Index (HCI) in Colombo Metropolitan Area, Sri Lanka (1997-2022)
No full textHuman Comfort Index (HCI) is used to calculate Human Heat Stress (HHS). Heat stress management is an important area to address through policies and plans, including considerations related to extreme heat impacts in vulnerable communities. In this study, we analyze the historical trends in human comfort (measured by Temperature Humidity Index) in Colombo Metropolitan Area (CMA), Sri Lanka from 1997 to 2022. It would be very useful for future studies, planning purposes and making policies for various sectors of development activities in Sri Lanka. Air Temperature and Relative Humidity data of Colombo, Katunayake & Ratmalana were obtained from the Department of Meteorology and Statistical abstracts and then calculated the annual, monthly and seasonal HHS. Linear regression and MS Excel 2016 and ArcGIS 10.8 have been used in data analysis. Additionally, previous research’s results were used for the comparison. Accordingly, a positive increasing trend in thermal discomfort (THI>26) is seen at three weather station areas in CMA throughout the 25 years and Katunayake area is slightly more comfortable than Colombo and Ratmalana. Monthly temporal analysis revealed that January & December are the most comfortable months during the last decade and April & May are the hottest and uncomfortable months. When considering seasonal analysis, Katunayake and Colombo have shown the discomfort level within the all four seasons-FIM, SWM, SIM & NEM. Heat Strokes highly to be prone in FIM and SWM. Comparison with the previous research also revealed that with the changes of NDVI, LST was increased and parallel to that HHS in CMA was increased. This study revealed a positive strong increasing trend of HHS in CMA from 1997 to 2022. It is not a big issue today, but the continuing increasing trend will cause several health complications in CMA, Sri Lanka.
Keywords: Colombo Metropolitan Area, Human Comfort Index, Human Heat Stress,
Sri Lanka, Weather Station
Modelling Options for Greenhouse Gas Emission Reductions: An Analysis of the Agricultural Sector in Sri Lanka
No full textReducing Greenhouse Gas (GHG) emissions is crucial for mitigating climate change. Agriculture is a significant contributor to GHGs. This study evaluates several options available for GHG emission reduction, related to crops, livestock and energy use in the agricultural sector in Sri Lanka. The data related to CO2, CH4 and N2O emissions, paddy yield and the area of cultivation were obtained from the database of the Food and Agriculture Organization of the United Nations and the Department of Agriculture. Paddy crop was modelled by assuming cultivation of an indigenous paddy variety, which uses organic fertilizer, in 5%, 10%, 15%, 20% and 25% of the total area available for paddy cultvation in the country. The avoided urea application and associated reduction of N2O emissions were considered. Use of petroleum was replaced with renewable energy sources (biomass). CH4 emissions from dairy and non-dairy cattle were modelled by assuming 5%, 10%, 15%, 20% and 25% replacement with feed additives, which reduce methane emissions from ruminants. Damage cost was calculated for the period from 2025 to 2050. According to the results, the social cost of carbon with the cultivation of an indigenous paddy variety for rainfed paddy ranges from USD 141 million to USD 111 million in 2025. The cost ranges from USD 484 million to USD 382 million for irrigated paddy. The benefit from organic paddy cultivation was higher than that of paddy cultivated using chemical fertilizer. Both the cost of fertilizer and the global damage cost were lower for organic paddy. With renewable energy replacing 25% of petroleum use, damage cost of CO2, CH4 and N2O emissions can be reduced to USD 7 million, USD 186 million and USD 1877 million respectively. With the reduction of CH4 emissions by 25%, the damage cost related to dairy cattle will be reduced to USD 36 million from USD 48 million in 2025. It will be reduced by USD 14 million for non-dairy cattle. Damage cost increases from 2025 to 2050, for all the options considered. The study reveals that the damage cost of GHGs can be reduced by introducing suitable options and highlights the importance of mitigating the impacts of GHG emissions. The outcomes of the study are important for policy-making in the agriculture sector.
Keywords: Greenhouse gas emissions, Social cost of carbon, Crops, Energy use, Livestoc
Water Quality and Microplastic Contamination Status of Surface Water in the Head and Transitional Regions of the Maha Oya Basin, Sri Lanka
No full textWater is essential for all forms of life, serving as a critical component for biological processes, agriculture, and industrial activities. It is a vital resource that supports ecosystems, human health, and economic development, making its conservation and sustainable management crucial for the future. Therefore, this study was focused on determining the water quality and microplastic contamination status of surface water at the head and transitional regions of the Maha Oya basin. The Maha Oya crosses three provinces and four districts in Sri Lanka. Thirty surface water sampling locations were selected for the study by representing the head and transitional regions of the Maha Oya (50.8 Km) from the Ahupini Ella to Allawwa within February by using a grab sampling technique in the similar distance method. Sampling, transportation and analysis were performed using standard methods. Water samples were analysed for pH, Total Dissolved Solids (TDS), Electrical Conductivity (EC), turbidity, Chloride, Total Hardness (TH) and MPs. The pH, TDS, EC, and Chloride were in the desirable limit while increasing the turbidity levels along the river. According to Pearson correlation analysis, a moderate positive correlation was observed in EC and TDS with pH. Additionally, A moderate positive correlation was found between EC and TH. The location M1 has the highest concentration of microplastic particles, exceeding 250 particles/m³. The M10 has the lowest concentration of microplastic particles of 10 particles/m³. Fibers were the dominant type of microplastic in the Maha Oya surface water representing 70% of the total abundance of microplastics, particularly 38% of blue fibers and 20% of black fibers. It was noticed that there was no significant correlation between the abundance of microplastics and water quality parameters. However, the findings highlight the urgent need for effective management strategies to mitigate plastic pollution and preserve water quality in the Maha Oya basin.
Keywords: Microplastics, Water quality, Maha Oya, Surface wate