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.

The global demand for plastic is increasing year by year due to its indispensable uses and excellent properties. Plastic wastes persist for many years due to their slow deterioration and cause severe environmental problems. Therefore, there is a growing focus worldwide on plastic waste disposal methods to overcome adverse environmental impacts. As plastics are petroleum-based materials, the pyrolysis of plastics to fuel oil, gases, and char, has more concern than the other plastic waste management methods of recycling and landfilling. A yield of 70-80 wt.% of liquid fuel from pyrolysis waste has been reported elsewhere, emerging the importance and aptness of this method in plastic waste management. The common reactor types for the pyrolysis process are batch reactor, semi-batch reactor, spouted bed reactor, and fluidized bed reactor. The common catalysts employed in plastic pyrolysis were zeolites, including ZSM-5, HUSY, Zeolite X, and Y. The pore structure and the catalyst’s acidity are the most influencing parameters in increasing the liquid yield and the quality of the oil produced in the pyrolysis process. This paper reviews the existing literature on pyrolysis processes developed for HDPE and LDPE wastes globally and their governing factors. Furthermore, emissions in the pyrolysis process and engine combustion of the fuel oil, performance, and emission characteristics were discussed. Although plastic waste separation prior to its management is a challenging process, this review highlights the conversion of waste plastic into energy as a smart way to meet the rising demands.

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.

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.