Microplastic (MP) pollution is a serious global issue affecting freshwater systems, coastal regions, and oceans. These non-biodegradable materials have a detrimental impact on marine species and ecosystems, disrupting their feeding, breathing, and reproduction. In this study, 120 samples of two species of shrimp, Penaus monodon and Penaus indicus, from ten locations in the Negombo lagoon in Sri Lanka were analyzed. MPs were extracted from gastrointestinal tracts (GI) and gills (GL) by alkali digestion followed by vacuum filtering. Stereomicroscopy coupled with advanced micro-imaging and analysis software was employed for analyzing the isolated MPs. A total of 415 items were identified as MPs with an average of 8.29 ± 4.63 items per gram of GI and GL in Penaus monodon and 5.52 ± 3.78 items per gram of GI and GL in Penaus indicus. The majority of MPs identified were fibers (93%), and the remaining ones were fragments. Most of the MPs were >1000 μm, and the most prevalent color was blue (61%), followed by red (15%), black (9%), and others, comprising polystyrene, polyamide, polyester, polypropylene, and rayon, as revealed by FTIR spectroscopy. This study highlights the prevalence of MPs in shrimps harvested from the Negombo lagoon and displays missing baseline data before the effects of fragmented nurdles from the X-Press Pearl incident.

Microplastics have emerged as a significant global environmental concern in the recent decade. The aim of this study was to elucidate microplastic contamination of commercial fish species in a natural lagoon environment. Microplastic contamination was examined in the gastrointestinal tracts and gills of 157 commercial fish from 18 species with varying feeding habits in a vital and sensitive lagoon ecosystem, which connects to the Indian ocean. Microplastics were extracted using digestion, followed by stereomicroscopic inspection using Nile Red stain, and identified via μ-FTIR analysis. Over half of studied fishes ingested microplastics (54.14%). Filaments (50%) and blue items (43%) were the most commonly ingested. Of all the fish species, Eubleekeria splendens had the highest average concentration of microplastics in GIT (1.41 ± 2.52 items/g w.w. tissues), although no statistically significant difference in amount of ingested microplastics (items/g w.w. tissues) was observed among species. The highest concentrations of inhaled microplastics were recorded in Sillago vincenti (1.38 ± 1.30 items/g w.w. tissues). The majority of the extracted microplastics (33%) belonged in the size class 500–1500 μm with rayon, polyethylene terephthalate, and polypropylene as the primary polymers. This study found no correlation between microplastic ingestion and fish species and feeding habits, but a positive correlation with fish size was observed. These findings reveal widespread microplastic contamination in edible fish, posing potential risks to commercially important species due to increasing pollution in lagoon ecosystems.

Large plastic items in the environment are degraded into tiny pieces known as microplastics (MPs). MP contamination in tropical lagoon ecosystems poses a significant pollution threat. The mud crab, Scylla serrata, is an important crustacean in the tropical lagoon, valued as a key source of edible seafood in Asia and Europe. The potential MPs of one hundred samples were examined using the stereomicroscope for characterisation, and further analysis was conducted using µ-FTIR. A total of 1157 MPs were found in the gills and gastrointestinal tract. The mean abundance (±SD) of MP in mud crabs was 11.57 ± 6.29 items/individual. MPs were detected in both tissues, displaying a variety of colours. Transparent MPs dominated the gills at 43.9%, while blue microplastics were prevalent in the gastrointestinal tract at 32.8%. The filament (fibre) was the most prominent MP type found in the gills and gastrointestinal tract. The collected MPs from both tissues were categorised into four size ranges: 0.05–0.25 mm and 1.00–5.00 mm were the common size ranges in the gills and gastrointestinal tract, respectively. The prominent polymer type was rayon. These findings provide considerable proof of MP contamination in the mud crab species Scylla serrata and its implications for food security.

The objective of this study was to determine the current status of water quality in three selected fishery harbours named Hikkaduwa, Galle, and Hambantota located in the Southern coastal stretch of the country. It also aimed to provide recommendations to prevent harbour water pollution and minimize post-harvest loses due to spoilage and finally to upgrade the quality of fish for human consumption. Field visits were carried out for three months period from May to July 2014. Three sampling locations from each fishery harbour were selected and total of 14 physicochemical parameters of water quality were measured to identify the pollution levels. Assessments were also carried out to evaluate microbial contaminations. Results revealed that pH, dissolved oxygen, salinity, nitrate-N, nitrite-N and electrical conductivity were within the acceptable limits in all harbours.

There has been a considerable amount of research investigating suspended sediment (SS) and water quality in river basins. However, there has been less attention to the suspended sediment behaviour in tropical river basins, especially in Sri Lanka. The Gin river basin is one of the major river basins in Sri Lanka and catchments consist of multi-land use systems. The behaviour of water quality, and suspended sediment with land use pattern is still not well studied in tropical river basin. Therefore, the aim of this study was to elucidate land use effects on suspended sediment and water quality in multi-land use tropical river basins. Elevated nitrate nitrogen concentrations were observed in the upper catchment and greater ammonia nitrogen concentrations were recorded in the lower catchment sampling locations. Also, higher fluxes of nitrate nitrogen and dissolved phosphate were observed during April to June and June to July, respectively. The major land use systems in the upper catchment portion consist of activities related to forest management while the lower catchment region has a higher percentage of agriculture and other land use related functions. Different land use pattern from forest to agriculture was increasing the suspended matter in the river water. Also, there was a very low concentration of suspended sediment and turbidity in the highly forested catchments in upper parts of the basin. This was expected since turbidity and suspended sediments increase with increasing amounts of agriculture and other land use activity. Also, statistical results prove that major physical and chemical water quality parameter means are different with three sub basins. In conclusion, the suspended sediment flux and discharge fits well with the linear regression model (R2 = 0.97) and would imply that the discharge can be used to predict the SS load from runoff.