University of Sri Jayewardenepura: Journals & Proceedings
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Comparative Analysis of Tree Growth in Yagirala Man-Made Forest and Sinharaja Natural Forest in Sri Lanka, and Implications for Sustainable Forestry Management
Get PDFDetermination of tree growth is an important aspect of sustainable forestry practices. In Sri Lanka, much research has been carried out to determine the tree growth in different forests. However, the comparison between natural and human-planted forests is not comprehensively studied. Therefore, this study aims to compare tree growth between the Yagirala man-made forest in Kalutara district and the Sinharaja natural rainforest in Rathnapura district, Sri Lanka, while focusing on assessing sustainable forestry practices and ecological adaptation. The parameters of tree height, Diameter at Breast Height (DBH), and the basal area of the trees were measured using the Clinometer method, DBH tape, and the standard formula for the basal area [ π× (DBH / 2)2], respectively. To measure these parameters, tree species of Artocarpus nobilis, Alstonia macrophylla, and Dipterocarpus zeylanicus were selected, and the total sample size for the study was 50 trees per study area (1 km2) with measurements taken in both the Yagirala man-made forest and the Sinharaja natural rainforest. To minimize the effects of variables like tree age and site conditions, standardized sampling was implemented by selecting trees of similar age and species and controlling for environmental factors. The one-way ANOVA method was applied to evaluate the differences in the growth performance across these two forest types. Results indicate that, for tree height and DBH, there were no statistically significant differences (p>0.05) between the Yagirala and Sinharaja forests, with mean heights of 14.70 m and 18.75 m, and mean DBH of 0.183 m and 0.325 m, respectively. However, the basal area reported a significant statistical difference (p<0.05), suggesting that the Yagirala forest’s mean basal area (0.039 m²) was considerably lower than that of the Sinharaja forest (0.118 m²). The mean height and DBH of trees in the Yagirala man-made forest are comparatively closer to those in the Sinharaja natural rainforest, indicating that these trees have adapted well to the growing conditions. Although the basal area of trees in the Yagirala forest is significantly lower than that in the Sinharaja forest, this gap does not diminish the potential of man-made forests. The observed differences may be linked to factors like age, species composition, and applied management practices. With ongoing management practices and time, the Yagirala forest's basal area will improve, further enhancing its ecological value. In conclusion, these results demonstrate how well artificial forests can adjust to environmental factors that support tree development and ecological function.
Keywords: Man-made forests, Tree growth measurements, Yagirala, Sinharaja, Sri Lank
Adsorptive Removal of Copper in Aqueous Solutions using Pandanus kaida Leaf Powder
No full textThe study focused on investigating the feasibility and potential of Pandanus kaida (watekeiya) as a novel adsorbent for the removal of Cu (II) from aqueous solutions through evaluation of adsorbent characterization, batch adsorption, kinetic, adsorption isotherm, and regeneration studies. The initial and residual metal concentration in the solution was quantitatively analyzed using Flame Atomic Absorption Spectroscopy (FAAS). The optimum conditions for the maximum removal of Cu (II) by the adsorbent were found to be: 0.300 g in 100 mL of the adsorbate solution at pH 6 for 120 minutes contact time at a temperature of 60 ℃ and with a particle size of 250 µm. The adsorption isothermal studies conducted at 30℃, employing the use of Langmuir, Freundlich and D-R isotherm models revealed the Langmuir model as the best-fitted model with a correlation coefficient of 0.96 suggesting the occurrence of monolayer adsorption for the removal of Cu (II) by watekeiya leaf powder. The maximum monolayer adsorption capacity obtained from the Langmuir isotherm model was 15.45 mg g-1 at 30 ℃. The adsorption kinetics revealed that among pseudo-second-order, pseudo-first order, intraparticle diffusion and liquid film diffusion models, experimental data fitted the pseudo-second-order kinetics model the best with a correlation coefficient of 0.98 indicating that the rate-determining step of the adsorption proceeded via chemisorption. The regeneration studies carried out for two consecutive cycles confirmed the reusability of the absorbent. The characterization of the adsorbent done using FTIR revealed the presence of hydroxyl, amide, ether and carbonyl. The SEM analysis done on the adsorbent showed an irregular surface structure with pores which can aid in adsorption.
Keywords: Heavy metals, Batch adsorption, Kinetic model, Isotherms, Water pollution 
Antibiograms and Multi-Antibiotic Resistance of Staphylococcus and Micrococcus Species Isolated from Chlorinated Drinking Water Supply of the Mahaweli River, Sri Lanka
Get PDFContamination of antibiotic-resistant bacteria (ARB) in drinking water sources poses a growing threat to public health. Monitoring antibiotic resistance patterns in water systems is crucial for understanding the spread of bacteria with multi-antibiotic resistance (MAR). The present study focused on identifying antibiograms and MAR of predominant bacterial isolates from chlorinated drinking water collected from outlets of 14 water treatment plants along the Mahaweli River between Kotmale and Victoria reservoirs. Water samples were initially cultured on nutrient agar and Staphylococcus spp. (SC. spp.) (n=101, 74.3%) and Micrococcus spp. (MC. spp.) (n=35, 25.7%) were then identified using Gram staining and biochemical analyses. Antibiotic resistance of these isolates was evaluated using the Kirby Bauer disc diffusion method with a panel of 10 antibiotics; cefuroxime (CXM-30), ceftazidime (CAZ-30), augmentin (AUG-30), cefoxitin (FOX-30), gentamycin (GEN-10), tetracycline (TE-30), ciprofloxacin (CIP-5), chloramphenicol (C-30), clindamycin (CD-2) and co-trimoxazole (SXT-25), as referring to CLSI-2021 standards. Antibiograms showed highest resistance to CAZ-30 (n=80, 79.2% for SC. spp. and n=24, 68.6% for MC. spp.), a third-generation cephalosporin, and subsequent resistance to other commonly used antibiotics; CD-2 (n=45, 44.6%, for SC. spp. and n=19, 54.3%, for MC. spp.), C-30 (n=34, 33.7% for SC. spp.) and CXM-30 (51.4%, n=18 for MC. spp.). Resistance to AUG-30 and SXT-25 was notably low, with only 3.0% and 5.7% of SC. spp. and MC. spp. isolates respectively exhibiting resistance to each antibiotic. Only three (3.0%) SC. spp. and one (2.8%) MC. spp. isolates were sensitive to all tested antibiotics. Having resistance to two or more antibiotic classes, 61.4% (n=62) of SC. spp. and 62.9% (n=22) MC. spp. isolates exhibited MAR. Calculated multi-antibiotic resistance indices (MARI) for both isolates ranged from 0 to 0.71, where 21.0% (n=13 out of 62) and 9.1% (n=2 out of 22) of MAR isolates of SC. spp. and MC. spp., respectively were greater than 0.5, indicating the possibility of resistance to >3 of seven classes of tested antibiotics. Contamination with ARB and MAR isolates may indicate that chlorination alone is not effective in eliminating ARB from drinking water. The detection of MAR SC. spp. and MC. spp. in chlorinated drinking water supply raises concerns about the potential spread of ARB via treated water systems, with implications for public health.
Keywords: Antibiotic susceptibility test, Disc diffusion method, Multi-antibiotic Resistance Index, Water treatment plant
An Assessment of Household Water Usage Patterns and Challenges in Koralaipatru West and Central Divisional Secretariat Divisions, Batticaloa District in Sri Lanka
No full textAccess to clean and reliable water is an essential item identified under the sustainable development goals. Many parts of the world face problems on water supply and access, its quality, sufficiency and purity. Households in Koralaipatru West and Central Divisional Secretariat divisions (DSDs) in Batticaloa district also face the same problems. The aim of this study was to quantify household water consumption patterns, characterize water sources and identify water quality and accessibility problems in both the DS divisions to interpret the factors influencing domestic water consumption. The primary data was collected through a questionnaire survey employing 50 households in both the DS divisions and focused group interviews with public health inspectors. Main sources of water in the study areas are identified as private, tube and driven wells, NWSDB supply, Pradeshiya Sabha water tankers and bottled water. Many of the wells used by the households were destroyed due to land pressure on urbanization in the construction of houses. According to public health inspectors, more than 90% of wells yield poor quality water that is not suitable for drinking due to fecal contamination caused by dense population in the urban areas. NWSDB supply is mainly used for drinking purposes. The daily average water consumption of the study area is 150 L per person per capita per day and NWSDB supply usage ranges between 1-5 m3 per household per month. Heavy water scarcity is observed in rural area during the dry season. Some people in the rural areas still don’t have any permanent water sources in their premises and they are fully dependent on the Pradeshiya Sabha water tankers and nearby mosques and houses which have permanent water sources. The NWSDB supply is also not provided continuously in the rural areas and many houses in the rural areas are not connected yet with the NWSDB supply. Less than 50% of the households have NWSDB supply in the rural areas. People in the rural area save water in water storage tanks during the rainy season to use in the dry season. Bad smell, turbidity, oily appearance and contamination from nearby toilets are the water quality issues in both the areas. This study highlights the importance of improved water infrastructure in rural areas and enhanced water quality monitoring and treatment systems in both the areas. Implementation of sustainable water management practices are needed to ensure the safe and reliable water for household use in both the DS divisions.
Keywords: Water scarcity, Water sources, Daily water usage, Water infrastructure, Water qualit
Sustainable Production of Fungal Pigments from Selected Agro-Food Wastes via Submerged Fermentation Process using Fusarium proliferatum Strain 08405: A Biovalorization Approach
No full textBiovalorization utilizes biological processes to convert waste materials into valuable products, enhancing sustainability and resource efficiency. This study focuses on developing and optimizing a sustainable approach to the production of fungal pigments via submerged fermentation (SMF) process using Fusarium proliferatum strain 08405. The fermentation substrates included banana peel waste, affected Sesbania grandiflora leaves and stems, and used tea dust waste. Key physico-chemical properties of the substrates, such as pH, moisture content, total organic carbon, and total ash content were analyzed using standard methods. The fungal cultures were incubated under optimal conditions at 25 and 160 rpm for 14 days. Pigments were extracted using cold, buffered methanol (98%, 2% ammonium acetate, 0.5 M) and characterized by colour observation, UV-Vis spectroscopic analysis, and Fourier-transform infrared (FTIR) spectroscopic analysis. Toxicity, antibacterial, and antioxidant properties of the pigments were assessed to determine their potential for industrial applications. The pigment yields from banana peel, Sesbania, and tea wastes were 375.2±22.8 mg/L, 161.4±7.8 mg/L, and 102.2±6.8 mg/L, respectively. Significant differences (p<0.05) in pigment yields were observed between different substrate types. The pigments exhibited a yellowish orange colour, with UV-Vis spectra showing a λmax between 200-300 nm and a minor peak around 500 nm. FTIR analysis revealed characteristic peaks for functional groups, including OH-stretching (3000-3500 cm⁻¹), CH-stretching (2800-2950 cm⁻¹), carbonyl C=O stretch (1630-1980 cm⁻¹), C-O stretch for quinones (1060-1590 cm⁻¹), aromatic ring C=C stretching (1500-1600 cm⁻¹), and CH-bending (650-800 cm⁻¹), suggesting the presence of a Naphthoquinone type pigment. The Artemia salina toxicity bioassay indicated a low mortality rate (13-20%) for extracted pigment samples, compared to 100% for the positive control. Antibacterial activity demonstrated inhibition zones ranging from 1.5±0.1 cm to 2.1±0.1 cm for Staphylococcus aureus and 1.4±0.1 cm to 1.7±0.1 cm for Escherichia coli. The antioxidant assay showed increased DPPH inhibition with higher pigment concentrations, indicating strong free radical scavenging activity. This study presents a novel and sustainable method for producing fungal pigments via submerged fermentation using selected agro-food wastes and Fusarium proliferatum strain 08405, an approach not previously documented.
Keywords: Agro-food waste, Biovalorization, Fungal pigment, Fusarium proliferatum strain 08405, Submerged fermentation proces
Assessment of Vegetation Changes and Seawater Intrusion in the Lower Bentota Ganga Sub River Basin: A Study of Land Use and Land Cover Change
No full textThe Lower Bentota Ganga sub-river basin faces challenges associated with both Land Use and Land Cover changes (LULCC) and seawater intrusion (SWI), impacting environmental sustainability and community livelihoods. This study investigates these issues using a multi-method approach. The primary objectives were to analyze historical LULCC and to understand community experiences of these changes. Landsat images were analyzed and classified using satellite imagery from 1988 to 2022 using ArcGIS Pro, to determine changes in LULC. A questionnaire survey was conducted among 150 respondents in key locations identified through the image classification, offering qualitative insights into the community's experience of LULCC and SWI impacts. 135 groundwater samples were taken around the region to determine electrical conductivity (EC) and geographic changes in salinity levels. The study reveals significant alterations in the landscape between 1988 and 2022. A notable reduction in vegetation cover was observed, alongside a rise in built-up and barren land, while water bodies remained relatively stable. A questionnaire survey provided valuable insights into the adverse effects of SWI on daily activities and local livelihoods, with respondents reporting increased salinity in groundwater affecting household and agricultural activities. These perceptions were corroborated by EC measurements, which showed significant spatial variation in salinity levels, particularly near the estuary and upstream areas. The study provides critical insights into LULCC and SWI in the Lower Bentota Ganga sub-river basin by integrating community insights with remote sensing (RS) and geographic information system (GIS) data. The findings emphasize the need for targeted interventions and ongoing monitoring to mitigate the impacts of these changes effectively and efficiently. This underscores the need for improved maintenance of floodgates and seawater exclusion structures and greater community involvement in land use planning. The study highlights the importance of addressing environmental challenges in coastal regions to develop effective sustainable development and environmental management strategies.
Keywords: Land use and land cover changes, Seawater intrusion, Geographic information systems, Lower Bentota ganga sub-river basin, Community experience
Identifying the Influential Factors of Coconut Exports and Their Interrelationships to Enhance the Competitiveness of Sri Lanka's Kernel Product Exports in the Global Market
No full textSri Lanka’s coconut industry is pivotal among the nation’s exports, with kernel products representing a significant share of agricultural exports. This study explores the factors influencing the exports of coconut kernel products in Sri Lanka and their interrelationships. Monthly data on exports of kernel products, total coconut production, domestic consumption, Free on-board (FOB) value per nut in Sri Lanka and total FOB value of the Philippines, which is one of the main competitors, for the period of 2012 to 2023 were obtained from the Coconut Development Authority. The Vector Autoregressive (VAR) model was employed to analyze the data, using the EViews software package. According to the results of the Wald test, lagged values of coconut exports (F=7.31, p<0.05) and coconut production (F=3.06, p<0.05) are significant drivers of export performance. Results of the Portmanteau Autocorrelation test reveal that there is no serial autocorrelation, indicating that the model is acceptable. Coconut production granger causes exports, and a joint causality effect exists from total coconut production, domestic consumption, FOB prices in Sri Lanka and in the Philippines towards exports. Moreover, production granger-causes consumption. Impulse response analysis shows that the level of coconut exports fluctuates over time through positive and negative values for a shock given to the production, domestic consumption, FOB prices in Sri Lanka and in the Philippines, and the impact dissipates in the long term. The level of domestic consumption fluctuates significantly for a shock given to production. The variance decomposition analysis reveals that the variation in coconut exports is considerably explained by the level of exports itself both in the short and long run. When moving from short-term to long-term, the contribution from production (5.25%), consumption (0.34%), Sri Lankan FOB price (2.35%) and the FOB price of the competitor (6.67%) increases. The outcomes of the research emphasize that production, consumption, FOB prices of Sri Lanka and the competitor are important in determining the level of coconut exports in Sri Lanka. Identifying the influential factors and their interconnections offers invaluable insights for policymakers and stakeholders in Sri Lanka’s coconut industry, and aids in formulating specific policies that can enhance the competitiveness of Sri Lanka's kernel product exports in the global market.
Keywords: Coconut exports, Coconut production, Domestic consumption, FOB, Vector autoregressio
A Comparative Analysis of Invasive Tree Decay Detection Techniques
No full textTree decay detection is a crucial component in Urban Forestry. There are invasive as well as non-invasive tools available worldwide for tree decay detection. This study is about a comparative analysis of different invasive techniques for detecting tree decay and cavities. The techniques compared here are traditional decay detection drills, radiographic techniques, acoustic detection, acoustic tomography, and electrical resistivity methods. Traditional tools such as decay detecting drills, increment borers and borescopes are suitable for preliminary investigations. Holes drilled into wood tissue by these tools may lead to fungal invasion. Radiographic techniques use X-ray or Gamma ray radiation where decay is detected by the decreasing wood density resulting from the biodegradation of cell walls. It is very effective in analyzing microscopic decay processes, but power consumption is heavy and has a high risk of radiation hazards. The resolution of radiographic methods is very high compared to other techniques. Acoustic techniques measure the increased transit time of an ultrasound or a stress wave pulse across a tree stem. Tools that use acoustic techniques can provide detailed information on wood quality with moderate to high resolution with quick results but are unable to locate and give the extent of decay. Acoustic tomography techniques generate images of internal wood structures using the principle of reduced velocity of sound waves in decayed wood. Tools such as Picus Sonic Tomograph can locate the defects, estimate their size, shape and determine the relative strength loss of degraded wood. Electrical resistivity techniques measure the reduction of electrical resistance in decayed wood due to the increasing concentration of mobile cations in the decayed region. Electrical resistivity tools such as Shigometers are most suitable for early detection of wood decay. But results should be validated with other methods such as tomography techniques for better accuracy and validation since fungal activities without decay can also cause lower electrical resistivity. In terms of the cost of these tools, radiographic tools are the most expensive while electrical resistivity meters are the cheapest. Apart from these, emerging techniques such as advanced mechanical probes, innovative ultrasonic and stress wave devices for detailed internal imaging, digital microprobes, acoustic emitting monitoring for real time decay tracking and computed tomography for three-dimensional analysis focus on reduced invasiveness alongside increased accuracy and detailing.
Keywords: Urban forestry, Tree decay detection, Invasive, Accurac
Ensuring Sustainability through Environmental Assessments in Sri Lanka: A Critical Review of Status, Gaps, and Way Forward
No full textThis review critically examines Sri Lanka's environmental assessment framework, focusing on implementation gaps across different scales of development projects and their cumulative environmental impacts. The study evaluates current assessment mechanisms and proposes recommendations for strengthening environmental governance at national and sub-national levels. The analysis of Sri Lanka's environmental assessment framework reveals that while robust requirements exist for large-scale projects, significant gaps persist in addressing impacts of medium and small-scale developments. Despite their individual modest scale, projects such as small-scale tourism developments, informal settlements in sensitive zones, and scattered industrial facilities collectively contribute to substantial environmental degradation, often escaping rigorous environmental scrutiny. Critical weaknesses include inadequate attention to environmental examinations at local government level, poor implementation of Environmental Management Plans, and weak monitoring mechanisms. These challenges are exacerbated by insufficient technical expertise and staff capacity at provincial and local levels, alongside limited awareness among stakeholders, including financial institutions. Recommendations include establishing Strategic Environmental Assessment mechanisms for evaluating cumulative impacts, strengthening environmental examination procedures at Pradeshiya Sabha level, enhancing institutional capacity through increased technical staff and training, developing stakeholder awareness programs, and strengthening monitoring mechanisms. These measures aim to ensure sustainable development across all project scales in Sri Lanka.
Keywords: Environmental assessment, Cumulative impacts, Institutional capacity, Environmental management, Sustainable developmen
Adsorption Studies in a Packed Bed Column for the Removal of Ca²⁺ and Mg²⁺ Ions from Water Using a Novel Polyacrylamide-Strychnos potatorum Seed-Derived Activated Carbon Composite (Pa-Acsp)
No full textCalcium (Ca²⁺) and magnesium (Mg²⁺) ions contribute significantly to water hardness, which poses challenges in both residential and industrial settings. In Sri Lanka, especially in the Anuradhapura District, elevated hardness levels in drinking water are also hypothesized to be a factor in the incidence of chronic kidney disease of unknown etiology (CKDu). Drinking water in this region typically has Ca²⁺ concentrations averaging 212 ppm (ranging from 5–429 ppm) and Mg²⁺ concentrations averaging 78 ppm (ranging from 2–160 ppm). WHO recommended values for maximum Ca2+ and Mg2+ ion concentrations in drinking water are 100 ppm and 30 ppm, respectively. Adsorption is a widely recognized method for the effective removal of Ca²⁺ and Mg²⁺ ions from water. This study investigates the adsorption efficiency of a packed bed column filled with a polyacrylamide-Strychnos potatorum-derived activated carbon composite (PA-ACSP) for reducing water hardness.The primary goal of this research is to develop a user-friendly, economical and efficient water filtration method to mitigate water hardness, particularly in CKDu-endemic areas. The PA-ACSP composite adsorbent was synthesized by combining activated carbon derived from Strychnos potatorum seeds (ACSP) with acrylamide. The composite was characterized using Fourier-transform infrared-attenuated total reflection (FTIR-ATR) spectroscopy. To evaluate the adsorption performance, experiments were conducted to assess the impact of variables such as flow rate, bed height, and inlet ion concentrations on the removal efficiencies of Ca²⁺ and Mg²⁺. Experiments were conducted at a constant temperature with fixed column dimensions. Results indicated that increased bed height enhanced removal efficiency for both ions, while higher inlet concentrations and flow rates resulted in decreased efficiency. Preliminary optimization of column parameters 6 cm in diameter, 10 cm bed height, with a 200 ppm Ca²⁺ solution and a 75 ppm Mg²⁺ solution revealed that approximately 4.5 L of water could be treated, achieving around 67.02% (±0.4) Ca²⁺ removal efficiency and 73.31% (±0.86) Mg²⁺ removal efficiency. These findings suggest that with further refinement, the packed bed column design could be adapted into an effective water filtration solution for reducing water hardness, particularly in areas affected by CKDu in Sri Lanka.
Keywords: Ca(II), Mg(II), Strychnos potatorum, Polyacrylamide, Composit