Browsing by Author "Liyanage, Uditha Prabhath"

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    Macrobenthos-based RBP I l (Rapid Bioassessment Protocol Il) as a tool to assess the sediment and water quality in a treated textile effluent receiving stream ecosystem associated with a wetland marsh: A case study from Sri Lanka
    (Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka., 2021) Wijeyaratne M, W. M. Dimuthu Nilmini; Liyanage, Uditha Prabhath
    Macrobenthos are important bioindicators of organic and nutrient pollution. The present study used the macrobenthos-based rapid bioassessment protocol (RBP Il) to study the effects of treated textile effluent inputs into a natural stream ecosystem connected to a wetland marsh. Three reference sites and three sites receiving point source inputs from a textile effluent treatment plant were selected. The physical and chemical parameters, and the abundance and diversity of macrobenthos at each site, were assessed during the rainy and dry seasons of 2020. Although the water quality parameters at the sites representing the point source inputs did not exceed the standard textile effluent discharge limits, a significant influence on the macrobenthic community composition was observed at the effluent discharge receiving sites. The dominant macrobenthos in the ecosystem (Baetis sp., Leptoph/ebia sp; Tubifex sp.) exhibited significant correlations with lead, copper, chromium and cadmium concentrations of the water and sediments. The Shannon-Weiner Diversity Index, Family Biotic Index, EPT Index and EPT/C ratio used in the rapid bioassessment protocol indicated significantly strong correlations with the water and sediment quality parameters, demonstrating their suitability to be used as a tool for biological measurements in aquatic ecosystems receiving textile effluents.
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    Multimetric socio-ecological assessment of water hyacinth (Eichhornia crassipes (Mart) solms) invasion of an urban Ramsar wetland lake
    (Wiley, 2024) Wijeyaratne, W. M. Dimuthu Nilmini; Liyanage, Uditha Prabhath
    Water hyacinth (Eichhornia crassipes (Mart) solms), a widely distributed invasive aquatic plant in Sri Lanka, has invaded the Diyawannawa wetland lake located in Colombo city, which is the first Ramsar wetland city in South Asia. The present study was conducted to assess the water quality parameters that influence the distribution of water hyacinth and to identify the environmental, economic, and social consequences of its invasion of the Diyawannawa wetland. Five sampling sites were selected from the Diyawannawa lake, and the water pH, temperature, conductivity, total dissolved solids (TDS), salinity, dissolved oxygen concentration (DO), nitrate concentration, and total phosphorus concentration were measured at monthly intervals in the rainy and dry seasons of 2020. The abundance of water hyacinth was recorded at each site at each sampling event. Interviews and focus group discussions (FGDs) were conducted with the representatives of the community associated with the wetland to assess the ecological, economic and social effects of water hyacinth invasion. Principal component analysis of the water quality parameters revealed that phosphorus and nitrate concentrations in water significantly influenced the abundance of water hyacinth. Further, the water quality index (WQI) indicated poor water quality in the sites invaded by water hyacinth. The interviews and FGDs revealed that water hyacinth invasion has adversely affected the lake's fisheries and navigation pathways and increased the frequency of flooding, resulting in an increased mosquito population. The results of the present study highlighted the importance of implementing water quality management programmes in the Diyawannawa wetland to control the invasion of water hyacinth. Further, we recommend increasing community participation in water hyacinth control programmes and providing opportunities for the community to engage in self-employment activities associated with the uses of water hyacinth.