Browsing by Author "Sewwandi, B.G.N."

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Application of water pollution and heavy metal pollution indices to evaluate the water quality in St. Sebastian Canal, Colombo, Sri Lanka.
(Environmental Nanotechnology Monitoring and Management, 2023) Hemachandra, S.C.S.M.; Sewwandi, B.G.N.
Anthropogenic pollution plays an important role in deteriorating the water quality of canals worldwide, espe- cially in developing countries like Sri Lanka. The St. Sebastian Canal is one of the main canals in Sri Lanka, which runs through Colombo city that collects massive quantities of domestic, municipal, and industrial waste products. The aim of the present study is to develop water pollution and heavy metal pollution indices to assess the water pollution status of the St. Sebastian canal, Colombo by comparing water quality parameters with ambient water quality standards for aquatic life in Sri Lanka. Water samples were analyzed for physical and chemical param- eters and heavy metals. Ultimately, Water Pollution Index (WPI) and Heavy Metal Pollution Index (HPI) were developed for several sites along the canal. WPI ranged from 0.64 to 1.93 with a mean value of 1.12, indicating water of St. Sebastian canal is highly polluted. The mean value of HPI was found to be 50, which is higher than the critical HPI value of 30, thus indicating that water of the canal is critically polluted with heavy metals. Further, sites 1, 5, 6, 7, 8 and 9 and sites 1, 4, 5, 6, 7, 8 and 9 were found to be highly polluted as per the WPI and HPI, respectively. This shows the importance of having both WPI and HPI to assess the level of water pollution as site 4 is being categorized as a highly polluted site by HPI and as a good water quality site by WPI. Therefore, the site-specific assessment of water pollution by WPI and HPI will help the relevant authorities to implement remediation methods with respective to the critical pollutants in a particular location, to identify the polluters and to take measures to prevent the discharges to the water body from different sources.
Assessment of the quality of composts in selected commercial compost facilities in Sri Lanka
(Faculty of Science, University of Kelaniya, Sri Lanka, 2020) Udayanthika, S.K.I.; Sewwandi, B.G.N.
Organic food production is one of the fast-growing sectors in Sri Lanka with an understanding of health and environmental impacts caused by the use of chemical fertilizers. Hence, there is a high demand for compost by organic agriculture and it is widely used in home gardening as a substitute for chemical fertilizers. The compost produced by using different raw materials are available in markets at present in Sri Lanka. Even though the quality of the compost has to be in accordance with the Sri Lanka standard specification (SLS 1246:2003) for compost from municipal solid waste and agricultural waste, enough studies have not been carried out on the assessment of compost quality. Therefore, the objectives of this study were to assess the quality of compost collected from the commercial compost producing sites and to investigate the time period that can maintain the SLS standards specifications in compost once it is packed. The compost bags of 1 kg were collected within a day from 4 sites (namely A, B, C and D) in Colombo and Gampaha Districts, which have been packed on the same day and stored in the laboratory till analysis. The composts collected have been made from MSW (sites A, B and C) and garden waste (D). The compost quality parameters were measured in monthly intervals for a period of 6 months with three replicates. Data analysis was done by One-way ANOVA. Data analysis revealed that organic matter content and total carbon content in compost of A were lower than the standard limits during the study period. According to the results, the color of the compost in all composting plants was brownish black and complied with the SLS 1246:2003 standards. The compost did not emit irritable odors in any of the compost samples. Phosphorous content of compost from A and C was lower than the standard limit (0.5%) and Potassium content were lower than the standard minimum limit (1%) in C and D. Nitrogen content in compost from all the sites was lower than the standard minimum limit (1%). Composts from A, B, C and D indicated moderate phytotoxicity according to the germination index % values of 74, 67, 74 and 76, respectively which may be associated with the immaturity of the composts. Sand content was higher than the standard limit (10%) in compost plant D. It was found that most of the composting facilities could maintain the Phosphorous and Potassium within the SLS standard limits. However, Nitrogen content in compost from all the sites were lower than the standard limits and it was decreasing with time during the study period. The results showed that the compost produced in selected sites does not meet the standard specifications given by the Sri Lanka Standards (SLS 1246:2003) and therefore, quality control and continuous monitoring are essential to maintain the quality of compost available in the market. The quality control of compost has to be started from the selection of raw materials up to the detection of maturity of compost in order to produce a good quality product.
Cyanotoxins availability and detection methods in wastewater treatment plants: A review
(Elsevier Ltd., 2024) Manjitha, K.G.L.; Sewwandi, B.G.N.; Takahashi, Toshinori; Fujino, Takeshi
Research interest in ecological significance, toxicity, and potential applications of cyanobacterial metabolites has grown as a result of the current extensive cyanobacterial blooms in water bodies. Under favourable conditions, specific cyanobacterial species release cyanotoxins, hepatotoxins, dermatoxins, neurotoxins, and cytotoxins, creating a heightened threat to aquatic ecosystems and human health. Wastewater treatment plants (WWTPs) offer one of the best culture media for cyanobacterial development and synthesis of cyanotoxins by providing optimum environmental conditions, including temperature, light intensity, lengthy water residence time, and nutrient-rich habitat. To discover the intricate relationships between cyanobacterial populations and other living organisms, it is important to comprehend the cyanobacterial communities in the ecology of WWTPs. Monitoring strategies of these cyanotoxins typically involved combined assessments of biological, biochemical, and physicochemical methodologies. Microscopic observations and physicochemical factors analysis cannot be carried out for toxicity potential analysis of blooms. Due to their high sensitivity, molecular-based approaches allow for the early detection of toxic cyanobacteria, while biological analysis is carried out by using water bloom material and cell extracts to screen cyanotoxins build up in organisms. As each approach has benefits and drawbacks, the development of an integrated multi-method laboratory system is essential to obtain trustworthy results and accurate detection of cyanotoxin levels in WWTPs allowing us to take necessary proactive and preventative approaches for effective wastewater treatment.
A systematic literature review on integrating disaster risk reduction (DRR) in sustainable tourism (SusT): Conceptual framework for enhancing resilience and minimizing environmental impacts
(International Journal of Disaster Risk Reduction, 2024-08) Jayasinghe, G. Y.; Perera, T. A. N. T.; Perera, H. A. T. N.; Karunarathne, H.D.; Manawadu, L.; Weerasinghe, V. P. A.; Sewwandi, B.G.N.; Haroon, M. H.; Malalgoda, C.; Amaratunga, D.; Haigh, R.
This literature review meticulously explores the integration of Disaster Risk Reduction (DRR) techniques into sustainable tourism (SusT), placing a focal point on enhancing resilience and mitigating environmental impacts. By examining several disciplines, including tourism management, disaster management, environmental science, green innovation, and sustainable development, this study recognizes major themes, research gaps, and best practices in this emerging subject. It underlines the importance of SusT and the need for effective DRR programs to alleviate the negative effects of catastrophes on tourism destinations and ensure their long-term sustainability and resilience. Science Direct, Springer, SAGE Publications, and Wiley's online library were the selected databases and the inclusion criteria were based on studies that looked at how DRR measures were implemented in SusT practices and how effective they were in increasing resilience and lowering environmental effects. The selected literature reveals many concepts and ways for integrating DRR in tourism, such as pre-disaster planning, risk assessment, capacity building, and stakeholder involvement. The assessment identifies the vital part played by government agencies, local entities, and tourist service providers in organizing and coordinating these programs. It points out potential obstacles to DRR integration within the tourism sector. The review emphasizes the importance of monitoring and measuring the outcomes of DRR programs in tourism, and it suggests the use of metrics and indicators to assess how well resilience-building and environmental impact reduction strategies are implemented. These insights may be utilized by policymakers, academics, and practitioners to design methods that enhnace the resilience of tourism destinations while minimizing environmental consequences.
A systematic literature review on integrating disaster risk reduction (DRR) in sustainable tourism (SusT): Conceptual framework for enhancing resilience and minimizing environmental impacts
(Elsevier, 2024) Jayasinghe, G.Y.; Perera, T.A.N.T.; Perera, H.A.T.N.; Karunarathne, H.D.; Manawadu, L.; Weerasinghe, V.P.A.; Sewwandi, B.G.N.; Haroon, M.H.; Malalgoda, Chamindi; Amaratunga, Dilanthi; Haigh, Richard
This literature review meticulously explores the integration of Disaster Risk Reduction (DRR) techniques into sustainable tourism (SusT), placing a focal point on enhancing resilience and mitigating environmental impacts. By examining several disciplines, including tourism management, disaster management, environmental science, green innovation, and sustainable development, this study recognizes major themes, research gaps, and best practices in this emerging subject. It underlines the importance of SusT and the need for effective DRR programs to alleviate the negative effects of catastrophes on tourism destinations and ensure their long-term sustainability and resilience. Science Direct, Springer, SAGE Publications, and Wiley's online library were the selected databases and the inclusion criteria were based on studies that looked at how DRR measures were implemented in SusT practices and how effective they were in increasing resilience and lowering environmental effects. The selected literature reveals many concepts and ways for integrating DRR in tourism, such as pre-disaster planning, risk assessment, capacity building, and stakeholder involvement. The assessment identifies the vital part played by government agencies, local entities, and tourist service providers in organizing and coordinating these programs. It points out potential obstacles to DRR integration within the tourism sector. The review emphasizes the importance of monitoring and measuring the outcomes of DRR programs in tourism, and it suggests the use of metrics and indicators to assess how well resilience-building and environmental impact reduction strategies are implemented. These insights may be utilized by policymakers, academics, and practitioners to design methods that enhnace the resilience of tourism destinations while minimizing environmental consequences.conditions in Sri Lankan marine waters, thus qualifying mangrove ecosystems in microtidal coasts as effective carbon sinks.