Evaluation of Potential Coastal Resources for Promotion of Ecotourism, Climate Resilience and Blue Economy Development in the Vadamarachchy East Region of Jaffna, Sri Lanka

Coastal resources have a great potential for promotion of ecotourism and blue economic development, and they act as a natural defence playing a vital role in mitigating the impact of coastal hazards. These resources are important to conserve and reduce coastal disaster impacts, ensuring the human security, sustainability of livelihood and blue economy and strengthen climate resilience. The present study area is situated on the North-eastern coast of Jaffna District. The study attempted to evaluate the resource potentials for the promotion of ecotourism, climate change adaptation and blue economy development in the Vadamarachchy East area. The detail survey was conducted between 2016 to 2019. The Multi Criteria Decision Method (MCDM) and Criteria ranking method in GIS were used considering aspects of sand dunes, beaches, mangroves, birding sites, and cultural places for evaluating the potential status of ecotourism. The evaluation process for potential sites were conducted based on several criteria viz. tourist preferences, proximity to residential areas, tourist accommodation, distance from roads, scenic beauty, distribution, and available facilities. Risk analysis was performed to identify the hydro-climatic disaster risk areas using Semi structured questionnaire survey. Focus group discussions were conducted for identify the challenges in protecting the coastal resources. The final suitability map for ecotourism status was generated through Multi criteria analysis and vulnerable disaster risk areas were identified associated with sand dunes. The findings indicate that Vadamarachchy east area represents high potential based on sand dunes, bird diversity and cultural places. Casuarina forest of Manatkadu, Chundikulam estuary, beaches and blue economic resources are key features for ecotourism promotion. Sand dunes and casuarina forest are major protection barriers for resilience from hydro- climatic disaster. The study area from Vallipuram, and Manatkaddu to Chundikulam is associated with deep sea fishing for blue economic development. Unfortunately, at present, these areas are being threatened by climatic disasters due to unsustainable and illegal sand mining operations and lack of conservation and governance mechanism of vegetation. The study provided a set of recommendations to increase the effective use of ecotourism potentials, including sand dunes and coastal line vegetation because it can contribute to reducing negative effects of the climatic disaster and ensure the sustainable blue economy development. Hence, this study emphasized the multi stakeholder agencies’ participation for development planning, resource management which are required to reduce impact of climate change, increase adaptation, use the coastal resources for ecotourism promotion and blue economic development in sustainable manner.   Keywords: Blue economy, Climate adaptation, Ecotourism, Sand dunes, Vadamarachchy Eas

Spatial Variability of Selected Soil Chemical Parameters in Low-yielding Paddy Production Block in Mahaweli System H, Sri Lanka

Although water availability for paddy production in Mahaweli System H is abundant, paddy yield is lower in Nochchiyagama (278 km2), chosen for soil assessment. Paddy yield data were used to identify the low-yielding division using the area-weighted average. Twenty-five random locations were generated, and soil samples were collected for pH, soil conductivity (EC), salinity, and total dissolved solids (TDS) analysis. ArcGIS software was used to create spatial distribution maps and related geostatistical analyses for each parameter. Vector files were created with their associated properties, and thematic maps were generated using spatial interpolation techniques, such as universal kriging (UK), ordinary kriging (OK), and inverse distance weighted (IDW) methods of interpolation techniques to identify the best interpolation method for soil chemical parameters mapping. The entire Nochchiyagama land was observed to have a slightly acidic pH (5.6-5.9) range that may have affected rice crop growth due to nutrient mobility and uptake issues. The spatial interpolation evaluation suggests that at least two-thirds of the area observed for lower TDS levels (591-654 mg/L) is potentially unsafe paddy production. Elevated levels of EC (3.1-7.24 dS/m) along with TDS may lead to physiological drought due to interferences in ion uptake. In overall, spatial interpolation evaluation indicators suggest that the UK method was observed with a lower mean relative error (MRE) than the other two interpolations. However, EC distribution showed low MRE in both IDW and OK interpolation techniques. The IDW method was observed to have a lower RMSE (Root mean square error). The UK spatial interpolation performed better for TDS and salinity predictions than other methods. This study found consistent regional differences in low paddy yields in Mahaweli system H using the UK method for analyzing soil chemical parameters.  Keywords: Electrical conductivity, Interpolation errors, Salinity, Spatial interpolation&nbsp

Bacteria-based Sodium Alginate Formulation to Control Toxic Microcystis Blooms

Cyanobacterial bloom formation in freshwaters is a major socio-economic and health concern across the globe. Presently used chemical and physical control strategies are inefficient in complete removal of blooms and chemical application often lead to secondary pollution in water. Hence, the current study aimed to develop a bacteria-based formulation to control toxic bloom-forming Microcystis aeruginosa in freshwaters. Two bacterial strains, Exiguobacterium acetylicum and Pseudomonas previously isolated from Sri Lankan freshwaters and characterized for M. aeruginosa cell lysis and their microcystin (MC) toxin degradation were used in the study. Initially, suitability of bacterial strains to develop into solid formulations was evaluated through biofilm formation, antibiotic sensitivity and strain compatibility. Both strains formed biofilms on the surface of microtiter plates indicating their ability to attach and colonize on solid surfaces. The multiple antibiotic resistance indices for both strains were below the threshold risk level (0.2) against the seven tested classes of antibiotics. This result indicates that there is a low risk in introducing these bacterial strains to the natural environment. Further, plate assay showed that the two strains were compatible to stay together showing no antagonistic effect on the growth of each other. Having fulfilled all three criteria tested, the two strains were immobilized into beads (~5 mm) prepared from sodium alginate at 1:1 ratio of 1×108 cells/mL bacterial inoculum. Different weights (1.0, 2.0, 3.0 g) of bacteria-immobilized beads were enclosed in sachets made with Cambrella synthetic fabric. They were introduced to M. aeruginosa grown in BG-11 medium (OD=0.2, 730 nm) and kept at 26 °C. During incubation, growth stimulation of M. aeruginosa was visually observed in 1.0 and 2.0 g beads-containing cultures, whereas, gradual discoloration of colonies was observed with 3.0 g of beads. Microscopic observations also proved complete disintegration of M. aeruginosa colonies and lysis of cells in discolored cultures. After 15 days, M. aeruginosa cell lysis was estimated as a measure of chlorophyll degradation. The highest (8.4%) cell lysis was observed in cultures containing 3.0 g of beads. This indicates that bacteria cell lysis activity depends on the load of bacteria-immobilized beads. Degradation of MC toxin was estimated by enzyme-linked immunosorbent assay. The highest (57.6%) MC degradation was observed in cultures with 3.0 g of beads after 15 days of incubation. The efficiency of bacteria release from beads was tested by placing sachets in sterilized water. At 15 days, bacterial count in water was x107 CFU/mL, with all loadings of immobilized-bacteria indicating highly efficient bacteria release from the formulation. In conclusion, this study highlights that bacteria-based sodium alginate formulations can be made as a source of inoculum to control M. aeruginosa growth and MC degradation.  Keywords: Bacteria-based formulations, Cell lysis, Microcystis blooms, Microcysti

Testing the Biodegradability and Biodegradation Rate of Bio-based Film Products in Composting Environment

Bio-based film products have a considerable interest as a replacement for petroleum synthetic polymers of plastics. They are manufactured with a blend of corn starch such as Poly Lactic Acid (PLA) and Poly Butylene Adipate-co-Terephthalate (PBAT) based raw materials that have been specifically engineered to facilitate the process of biodegradation and compost ability. Hence, biodegradable polymers have been regarded as a promising solution to tackle the pollution caused by the wide use of conventional polymers. As the main responsible institute for integrating environmental considerations into the country‘s development process, the Central Environment Authority of Sri Lanka has taken an action to ban food wrappers (lunch sheets) made from conventional polymers in Sri Lanka. Thus, this study was to determine the biodegradability of bioplastic materials lunch sheets, available on the Sri Lankan market that are labeled as 100% biodegradable but not certified as compostable. The other specific objectives are to identify the biodegradability rate of each brand of lunch sheets, categorize those lunch sheets according to their biodegradability and finally get an idea to determine the optimum conditions for the biodegradation of a bio- based lunch sheet. In this study, the test was carried out in a controlled composting environment located in Gampaha–Dompe Green Park. Three different brands of biodegradable bio-based film products were tested together with cellulose paper as the positive control and nonbiodegradable lunch sheet (LDPE) as the negative control. The project length was 15 weeks. Samples were placed into frames which are made of wooden slats as width=280 mm, length=340 mm and height=50 mm and a 1x1 mm polyethylene mesh was fixed onto the frames. The methodology adopted was based on the study conducted in the Czech Republic in 2016. The emphasis was put on discovering whether bio-based film products are biodegradable or not. The biodegradability of each bio-based film product was tested using Visual inspection; the decomposed samples were inspected visually comparing with initial samples, Weight loss measurement; the initial weight and the weight after decomposition were measured using an analytical balance, FTIR and TGA analysis. Furthermore, the quality of the compost was analyzed using quality parameters such as pH, electrical conductivity, moisture, organic carbon%, nitrogen%, phosphorous%, potassium%, C/N ratio and S. The visual inspection of Sample C revealed large cracks and porous structure than Sample A and Sample B. Positive control was completely digested and the negative control stayed as it is. According to the weight loss measurement analysis, the positive control totally degraded and degradation order was Sample C>Sample A>Sample B. The TGA only suggested a partial degradation of samples. FTIR analysis indicated that the positive control was totally biodegradable, Sample B and sample C partially biodegradable and Sample A and negative control were not biodegradable. Based on the results it can be concluded that bio- based film products have not decomposed completely but their color, texture changed. Sample B exhibited the highest degradation rate and exhibited a high degree ofdecomposition. The degradation rate can be summarized as Positive control>Sample B>Sample C>Sample A> Negative Control respectively. The main conclusion from this study is that the biodegradation of bioplastics materials strongly depends on both the environment in which they are placed and the chemical nature of the material.  Keywords: Biodegradation, Biobased film products, Composting environment&nbsp

Degradation Potential of Biodegradable Plastics under Laboratory Conditions

Conventional plastics are one of the greatest environmental issues due to their excessive usage and slow degradation. Biodegradable plastics have been introduced as a promising solution to the issue. However, the degradation potential and the best exposure conditions for biodegradable plastics are not well understood in the local context. Therefore, the present study was conducted to evaluate the degradation potential of some commercially available single-use plastics labeled as ―biodegradable‖. Two brands of lunch sheets (LS1 and LS2) made from Polylactic acid (PLA), Polybutylene adipate terephthalate (PBAT), and corn starch, and one waste bag made from Low- density polyethylene (LDPE) and Linear low-density polyethylene (LLDPE) were tested against cellulose filter paper (FP) as a positive control. Degradation was tested using mass loss analysis, biogas production, and FTIR spectrum analysis together with visual analysis. The test materials were subject to different exposures, i.e., placed under seawater, beach sand, freshwater, sand with overlying freshwater, and under direct sunlight for 210 days, and anaerobic exposure for 60 days. LS1 had the highest mass loss of 73.3% in freshwater and the lowest of 9.5% in sunlight exposure. LS2 recorded the highest mass loss of 59.3% in compost exposure and the lowest of 2.9% in sunlight exposure. Waste bags recorded 1.5% as the highest mass loss in the sand with overlying freshwater and the lowest 0.3% under direct sunlight which is the lowest among all four samples. FP has shown the highest and lowest mass loss in composting and direct sunlight exposures at 79.7% and 6.2%. The degradation of FP indicates that the conditions required for biodegradation were present in the exposure environments. Direct sunlight exposure does not show a significant impact on the degradation of any of the test materials. The waste bag does not show considerable degradation under any exposure. The carbon dioxide gas production was 8.76×10-4 mol, 18.49×10-4 mol, and 2.88×10-4 mol in LS1, LS2, and waste bag, respectively. LS1 and LS2 showed visual damages and also changes in the FTIR spectrum. However, waste bags did not show any changes visually or in FTIR spectra. Therefore, it can be concluded that LDPE and LLDPE products did not undergo a detectable degradation though PLA, PBAT, and corn starch products show clear signs of degradation. The study needs to be repeated in situ to better understand the degradation behavior in actual exposure situations.  Keywords: Biodegradable plastics, Degradation, Plastic pollution&nbsp

Photocatalytic Degradation of Rhodamine B under UV Light Catalyzed by Alpha Titanium Phosphate and Metal Modified Titanium Phosphate

Wastewater management is a crucial issue in most emergent nations with ever-growing global industrialization. From textiles to food, mankind uses dyes and pigments which pose a threat to the environment due to organic non-biodegradable dyes contained in wastewater. Rhodamine B (RhB) is a conventional colorant in many industries producing a large amount of dye effluent, thus becoming a serious threat to the environment as well as human health. Additionally, RhB is dangerous even at extremely low quantities, making treatment of the RhB effluent more essential. Even though TiO2 is considered as the best photocatalyst to remove many organic pollutants, acceptable alternatives are needed due to being uneconomical in large-scale usage. Synthesis of titanium bismonohydrogen orthophosphate (α-TiP) can be achieved by refluxing ilmenite with phosphoric acid via a previously reported novel method. Solid state reactions of α-TiP and oxides of Co and Cu at 800° C result in various metal titanium phosphates (M-TiP) with unique colors. XRD, FTIR, and Diffuse reflectance UV-vis techniques were used for characterization of the obtained solids. Bandgap of α-TiP changed with the modification of different transition metal cations lowering bandgap from 4.01eV (α-TiP) to 3.57 eV (Cu-TiP). Aqueous RhB degradation under UV irradiation was used to investigate the photocatalytic abilities of these catalysts. For that 0.2 g sample of catalyst was added to a solution that contained 200 mL of a 5 mg L-1 Rh B which was kept for 15 mins in dark to reach adsorption-desorption equilibrium before exposing the sample to UV irradiation for 3 h. A clear enhancement of photocatalytic activity was observed from using Co- TiP as the catalyst, which only took around 80 min to remove almost all Rh B contained in the sample compared to α-TiP which took close to 3 h to become colorless. It was in alignment with spectrometer results where a clear reduction of intensity can be seen in wavelength at 552 nm. Photocatalytic activities of these catalysts decreased in the following order: Co-TiP>α-TiP>Cu-TiP. The Co-modified TiP showed degradation of 99.5% after 3 h of UV irradiation and pseudo first- order kinetics were followed by the degradation.  Keywords: Titanium Phosphate, Photocatalyst, Rhodamine B, Wastewater management&nbsp

Assessment of the Impacts of Atmospheric Pollution on Floristic Diversity and the Use of Lichens as Indicator Species for Assessing Atmospheric Pollution: in Sri Lanka: A Case Study of Three Tropical Forests in Central Highlands of Sri Lanka

The impacts of atmospheric pollution reach distant locations and are not restricted to the vicinity of the polluting sources. Pollutants of fine particulate matter impact the carbon, nutrient, and water cycling, primary production, crop and timber production in forest ecosystems. In Sri Lanka, fewer research studies have been carried out in assessing the impact of atmospheric pollution on forest ecosystems and also the use of lichens as a bioindicator in this context. Three forest reserves belonging to sub montane tropical forest category was selected for the study. The selection of the location was influenced by the fact that continuous monitoring of air pollutants had been done by the Central Environmental Authority in Kandy City and its environs. The three forest reserves located in the neighborhood of the Kandy City was taken for the study; Udawatte Kelle Forest Reserve, Gannoruwa Forest Reserve and Hanthana Forest Reserve. Transects having the width of 5m and plot length of 100m were laid in these forest reserves from the most disturbed areas to less disturbed areas. In each transect, the diameter at breast height (DBH) and height were recorded in all the plants having more than 5 cm DBH. The plants in the undergrowth were identified at generic and species levels. Samples of leaves, litter, soil were taken to the laboratory for analysis of nutrients; organic carbon, electric conductivity, pH, available potassium, nitrogen, Cation Exchange Capacity. Corticolous lichens (Lichens growing on tree trunks) above 1.5 m from the ground level were recorded in trees having >5 cm DBH in the plot. All lichens species were recorded and identified to the generic level, while some of the species were identified only to the family level at the field. Furthermore, numbers of thalli were counted excluding non-propagative thalli. The lichen samples taken to the laboratory were identified using light microscope, classified according to indicator species of air pollution based on the available literature. The results showed that despite the fact that the atmospheric levels of pollutants (PM2.5, PM10, CO, NO2 SO2 O3) were within the maximum permissible levels in the Kandy City and the neighborhood, Hanthane Forest Reserve showed lower levels for all the pollutants compared with the other two as it was located further away from the City. In the disturbed areas both the species diversity, lichen diversity was reduced showing some correlation with the level of disturbance. With regards to occurrence of lichens, Crustose lichens were the most abundant especially in the more disturbed areas and the occurrence of same was the least in Hanthane Forest Reserve which was the least disturbed among the three. Foliose lichens did not occur in Udawatte Kelle which was a high disturbed area. The bark pH in all the trees sampled showed values ranging from 5.4 to 6.0 and a significant relationship between bark pH and the lichen diversity could not be observed. Disturbed ecosystems shows poor nutrient cycling as their functions become stressed compared with the more naturalized ones.  Keywords: Air pollution, Lichens, Forests, Biodiversity, Nutrient cycling&nbsp

A Preliminary Survey of the Avifaunal Diversity in Pampaimadu Premise of the University of Vavuniya, Vavuniya, Sri Lanka

Vavuniya is a lowland dry zone district of the Northern Province of Sri Lanka, which is still unexplored with a natural forest cover of 1,238 km2. Even though there are many kinds of literature concerning the water birds of the Vavuniya, the diversity of tropical avifaunal species is still a gap which was the light of this study. The study area is situated 10 km from the center of Vavuniya along the A30 highway, with the dry-mixed evergreen forest as vegetation. The district is located within the dry zone which experiences a mean temperature of 28° C and annual rainfall of 1,400 mm. It also consists of 02 adjoined tanks along the boundary. The study points were used for the avifaunal survey during mid of March to end of July 2022. Habitat diversity within the study area was discussed using a prepared checklist and the community indices like the Shannon-Weiner index (H‘), Simpson‘s diversity index (D), Simpson‘s evenness (E), and Species richness (R) across various habitats ecosystem: Woodland-Paddy land (H1); Woodland-Water catchment area (H2); Forest (H3); Grassland with inundated land ecosystem (H4); and Manage Garden with Occasional trees (H5) of the study area. The checklist resulted in a total observation of 93 avifaunal species including 87 resident and 06 migrant species belonging to 47 families (including 09 endemics, and 05 nationally threatened species). Rock Pigeon (Columba livia) belongs to Family Columbidae with the highest frequency (68%, n=123) and is evenly distributed across different habitats but the family Ardeidae is found extensively dominating in H5 (39%). H1 is with the highest H‘ (3.5) and D (0.96); while H3 has the highest R (2.52) and E (0.62). The seasonally inundated habitats H2 and H4 bring water birds to the study area. It also increases the availability of avifaunal insectivores. Many anthropogenic disturbances, such as habitat alterations, intentional wildfire, and road mortality are the key threats encountered by the avifaunal species in the study area. In addition to that, the activity of stray dogs within the premises was observed to be a potential threat during the breeding season. Appropriate conservation strategies including landscape management, conservation of available forest land, and proper awareness of neighboring local communities are necessary to maintain the current ecological status.  Keywords: Avifauna, Checklist, Habitat variation, Species diversity, Vavuniya&nbsp

Unrevealing the Enhanced Laccase Activities of Phlebiopsis flavidoalba in the Presence of Lignin-Rich Raw Materials using Molecular Docking

Laccase, a versatile enzyme that belongs to the multi-copper oxidase family, exhibits extraordinary lignin-degrading capabilities. Among the diverse types of laccases, white-rot fungal laccases are considered some of the best lignin degraders, with various biotechnological and industrial applications. In our previous study, it was found that a wood-decaying white rot fungus, Phlebiopsis flavidoalba, is one of the highest laccase producers in vitro in the presence of rice husks as the raw material. However, it is unclear the exact mechanism and whether laccase directly interacts with the raw material, in this case, rice husks and its lignin model compound. Hence, the objective of the current study was to obtain laccase gene sequence from P. flavidoalba and subject it to molecular docking with lignin model compounds that are particularly found in rice husks to determine binding affinities to the active sites of enzyme. The laccase gene sequence of P. flavidoalba was obtained from the next-generation sequence data set obtained in our previous study and subjected to in silico homology modelling and molecular docking using various lignin model compounds reported to be present in rice husks. Firstly, to predict the 3D structure of the laccase of P. flavidoalba, homology modelling was performed using SWISS-MODEL. Laccase from Steccherinum murashkinskyi was selected as the template for homology modelling using SWISS-MODEL. CB-Dock server was used to perform molecular docking studies with a range of lignin model compounds, including sinapyl alcohol, coniferyl alcohol, - coumaryl alcohol, β-O-4′ aryl ether, β-5′ phenylcoumaran which are commonly found in rice husks. It was found that the above-mentioned lignin model compounds exhibited strong binding affinities such as -5.9 kcal/mol (sinapyl alcohol), -6.5 kcal/mol (coniferyl alcohol), -8.6 kcal/mol (- coumaryl alcohol), -7.5 kcal/mol (β-O-4′ aryl ether), and -7.5 kcal/mol (β-5′ phenylcoumaran) with the laccase protein of P. flavidoalba. The amino acid residues of modelled laccase in contact with the lignin model compounds forming hydrogen bonds were Gln457, Ile434, Phe432, Arg370, Lys452, Ile365. The insights gained from these docking studies can help uncover the molecular level interactions and the potential of utilizing such low-cost carbon sources for boosting laccase production.   Keywords: Homology modelling, Laccase, Lignin model compounds, Molecular docking, Rice husk &nbsp

Economic Feasibility of Reverse Osmosis (RO) Water Treatment Plants: A Case Study from Dimbulagala, Polonnaruwa, Sri Lanka

Social wellbeing is strongly linked with economic feasibility when it needs to attain with the technological advancements. Installation of Reverse Osmosis (RO) water treatment plants have been considered as a promising solution to provide clean water for human consumption, especially in the areas where the CKDu (chronic kidney disease of unknown etiology) prevails. At present, over 2,000 RO treatment plants were installed in the dry zone of Sri Lanka, yet economic feasibility for operation and maintenance of RO plants has not been assessed so far. The present study was intended to identify economic feasibility of operation and maintenance of RO plants. Investigations were carried out in six community RO plants which provided drinking water for over 17,000 people which accounts for 20% of total population in Dimbulagala Divisional Secretariat over a period of 12 months. Six in-depth interviews and questionnaire survey were caried out with RO plant operators. The operational cost per production of cubic meter of filtered water was computed by considering electricity consumption bills. The maintenance costs and service charges were also obtained from the records available with RO plant operators. The results found that the average electricity consumption to produce 1 cube of filtered water is approximately 9kWh and cost is LKR 734 (based on 2021 rates). The average water selling price ranged between LKR 1.00-2.50 per liter. The average monthly income generation from one RO plant is approximately between LKR 561- 875 per cube of filtered water and it largely depended on the type of water source, climatic conditions. It was found that the income generated from RO plants was sufficient enough to cover the operation cost (monthly electricity bill) and for the subsequent maintenance and service charges whenever required. It can be concluded that the use of RO treated water is an economically viable option to provide portable drinking water.  Keywords: CKDu, Economic sustainability, Drinking water, Purification cos