International Conference on Applied and Pure Sciences (ICAPS)
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Item Characterization of airborne microplastics in different indoor environments in University of Kelaniya, Sri Lanka-A preliminary study(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Saumya, R. L. K.; Deeyamulla, M. P.; De Silva, D. S. M.; Athukorala, A.; Bakir, A.; McGoran, A. R.Airborne microplastic (MP) contamination in indoor environments is an increasing concern due to potential health risks from inhalation. This study examined the distribution, polymer composition, and morphology of airborne MPs in five indoor settings at the University of Kelaniya, Sri Lanka. Passive sampling was conducted over 14 days in one office, two laboratories, and two lecture halls. A diverse array of MP forms and colors were identified using stereomicroscopy and advanced micro imaging. Further analyses were carried out using laser direct infrared spectrometer (LDIR) to identify the constituent polymer types of MPs. Fibers dominated the fallout samples in the office (100%), lecture hall 2 (60%), laboratory 1(56.25%), lecture hall1 (25%), whereas no fibers were found in the sample taken from laboratory 2. However, fragments were identified only in the sample collected from laboratory 2. Films were present at all locations except the office, but their number was relatively lower compared to fibers. The deposition rates of fibers were 3.7 × 102 fibers/m2/day in the laboratory 1, 0.82× 102 fibers/m2/day in the lecture hall 1, 1.23 × 102 fibers/m2/day in the lecture hall 2, and 1.64 × 102 fibers/m2/day in the office. The deposition rates of films in laboratory 1 and the lecture hall 2 were close to each other, corresponding to 1.64 × 102 films/m2/day. Among the selected indoor environments examined in this study, laboratory 1 exhibited the highest deposition rate of MPs on both fibers and films. The increased accumulation is likely due to the proximity of an active construction site, which could facilitate the transport of MPs into the laboratory. Furthermore, the laboratory's heavy use by approximately 60 students daily may have contributed to higher MPs levels. Conversely, laboratory 2 displayed the lowest deposition rate of MPs. This difference can be linked to several factors, including its relatively lower student occupancy, the shorter durations students spend within the laboratory environment and the air-conditioned nature. In all selected indoor environment settings, the prevalent color among MPs is transparent. Laboratory 1 exhibits a relatively balanced representation of transparent (35.29%), green (35.29%) and red (17.69%) MPs, while laboratory 2 predominantly comprises blue (50%) MPs. Lecture hall 1 shows a significant presence of blue MPs (50%), while lecture hall 2 primarily consists of transparent MPs (60%). The office environment exclusively contains transparent MPs. Laboratory 1 and laboratory 2 predominantly have MPs in the 100–250 μm range, while lecture hall 1 and lecture hall 2 show more varied sizes with larger particles being more prevalent, and the office environment mainly contains particles in the 250–500 μm. LDIR spectroscopy was revealed that the MPs were composed of polyamide (17%), polyethylene (10%), polyurethane (7%), polyester (6%), polypropylene (4%), and acrylonitrile butadiene styrene (2%). This study highlights the prevalence of MPs in various indoor environments, emphasizing the importance of evaluating health risks associated with long term exposure.Item Water quality dynamics in Anuradhapura, Sri Lanka: A comparative study from selected springs, wells, canals, and irrigation tanks(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Fonseka, G. K. D.; Pemarathne, S. K. S.; Amarathunga, A. A. D.; Nanthakumaran, A.; De Silva, D. S. M.Most of the residents in Anuradhapura consume untreated water from surface and groundwater sources, raising concerns about potential health risks. The water quality was assessed in major irrigation tank cascade system (Kalawewa, Rajanganaya, Nachchaduwa, Nuwarawewa, and Tissawewa) Anuradhapura and interconnected canals, wells, and springs. The objective of the study was to assess the quality of surface and groundwater, considering seasonal variations, and to identify potential contaminants that could contribute to health risks and irrigation purposes in the region. Water samples were collected from 78 locations in the wet season (December–February) and the dry season (June– July) in 2023 separately. Both in-situ [temperature, pH, electrical conductivity (EC), dissolved oxygen (DO), total dissolved solids (TDS),] and laboratory analysis [fluoride, chloride, bromide, nitrate, phosphate, sulfate, magnesium, Ca hardness, alkalinity, salinity, total suspended solids (TSS), turbidity, copper, zinc, chromium, and iron] were carried out using the APHA standard method (2017). The results of the physicochemical parameters were statistically tested using two sample t-test to identify seasonal change and one sample t-test to compare with drinking water quality standards WHO (fourth edition) and irrigation water quality standards (CEA 2019). The levels of temperature, EC, fluoride, bromide, chloride, TSS, and magnesium in surface water in the tanks were significantly higher in the dry season compared to the wet season (p<0.05). The level of chromium (wet: 0.30±0.04 mg/l, dry: 0.77±0.06 mg/l) and turbidity (wet: 7.39±0.94 NTU, dry: 6.86±1.14 NTU) in the tank water exceeded the WHO maximum permissible level during the wet and dry seasons (p<0.05). The levels of bromide (wet: 1.06±0.21 mg/l, dry: 18.24±2.78 mg/l) and chromium (wet: 0.03±0.02 mg/l, dry: 0.96±0.014 mg/l) in canals were significantly higher in the dry season compared to the wet season (p < 0.05) and exceeded the WHO maximum permissible level in the dry season. The level of calcium hardness (wet: 217.56±36.96 mg/l, dry: 179.13±34.06 mg/l) and chromium (wet: 0.24±0.05 mg/l, dry: 0.18±0.09 mg/l) in wells exceeded the WHO maximum permissible level in both seasons (p<0.05). The fluoride level in wells was significantly high in the dry season (2.59±0.31 mg/l) compared to the wet season (0.94±0.35 mg/l), which exceeded the WHO maximum permissible level in the dry season (p<0.05). The iron level of surface water in irrigation tanks (wet: 2.38±0.95 mg/l) and groundwater (wet: 1.87±0.71 mg/l) in wells in the wet season exceeded the WHO maximum permissible level (p<0.05). All physicochemical parameters of spring water were within permitted levels of WHO standards in both seasons. Groundwater in wells and surface water in tanks and canals situated in this area are not recommended for drinking purposes in both seasons without proper treatment. However, spring water is suitable for drinking purposes throughout the year, and groundwater in the wells and surface water are suitable for irrigation purposes throughout the year.Item Biofiltration of wastewater by mangrove ecosystem(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Sovis, W. S. N.; De Silva, D. S. M.; Chathurani, S. H. U.The mangrove ecosystem consists of salt-tolerant trees and shrubs that thrive in coastal intertidal zones. Mangroves are particularly important as natural biofilters, their dense root systems trap sediments and pollutants, while associated microorganisms break down organic matter, significantly improving water quality. This research aimed at determining the changes in water quality parameters after filtration through the mangrove ecosystem. The water samples were collected mainly in two sites as triplicates at the NARA regional center in Kadolkele, Negombo, Sri Lanka. Samples collected before filtration through the mangrove ecosystem were indicated as BMF samples, and the samples collected after filtration through the mangrove ecosystem were indicated as AFM samples. Samples were collected from August 2023 to January 2024. The data of different parameters were statistically analyzed using paired t-test in the Minitab 17 version. Ammonium ion levels were examined using the phenate method. The BMF samples (88.9 ± 20.5 ppm) indicated a significantly higher average value of ammonium ion than the AMF samples (62.7 ± 19.6 ppm) (p < 0.05). Phosphate levels were examined using the stannous chloride method. The BMF samples contained significantly higher phosphates (115.6 ± 12.8 ppm) than the AFM samples (75.8 ± 14.8 ppm) (p < 0.05). Nitrate levels were examined using the UV spectrometric screening method. The BMF samples showed a significantly higher average value of nitrate content (28.5 ± 6.2 ppm) than AMF samples (17.4 ± 6.1 ppm) (p < 0.05). There was no significant difference recorded between pH values of AMF and BMF samples (p > 0.05). The multiparameter analyzer was employed in measuring conductivity, resistivity, and total dissolved solid (TDS) levels. The BMF samples indicated higher resistivity and TDS levels than BMF samples, while the conductivity levels of AFM samples were higher than BMF samples. Average total suspended solid (TSS) levels were significantly higher in AMF samples (302.0 ± 12.3 mg/L3) than in BMF samples (272.1 ± 11.1 mg/L3) (p < 0.05). Heavy metal analysis was conducted by the atomic absorption spectrophotometer (AAS). Cu, Cr, Zn, Fe and Mn were the most prevalent heavy metals. Cd was not at detectable levels in both sampling sites. The average Cu level in the AMF samples (0.182 ± 0.035 ppm) was higher than BMF samples (0.172 ± 0.053 ppm), p = 0.551. Average Cr content was higher in BMF samples (0.105 ± 0.057 ppm) than in AMF samples (0.064 ± 0.019 ppm), p = 0.184. The average value of Zn in BMF samples (0.156 ± 0.066 ppm) indicated a higher value than AMF samples (0.106 ± 0.034 ppm), p = 0.138. But none of these were statistically significant. The average Fe content in BMF samples (0.331 ± 0.053 ppm) was significantly higher than that of AMF samples (0.131 ± 0.042 ppm), (p < 0.05). The average Mn level in BMF samples (0.020 ± 0.009 ppm) was significantly higher than AMF samples (0.004 ± 0.001 ppm) (p < 0.05). The average BOD level in AMF samples (4.0 ± 0.4 mg/L) was significantly higher than in BMF samples (3.0 ± 0.5 mg/L), (p < 0.05). The COD of BMF samples (185.3 ± 29.5 mg/L) indicated a significantly higher average value than AMF (150.5 ± 13.9 mg/L) samples (p < 0.05). The statistical analysis revealed a significant difference between AMF and BMF samples for ammonium ion, phosphate, nitrate, TSS, heavy metals (Fe, Mn), BOD, and COD, indicating the mangrove filtration's effectiveness in reducing these pollutants. However, there was no significant difference in pH levels and heavy metal concentrations of Cu, Cr, and Zn, suggesting that these parameters were not notably affected by the filtration process.Item Evaluating heavy metal accumulation in Scylla serrata (mud crabs) inhabiting the Negombo lagoon, Sri Lanka(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Dias, B. C. G.; De Silva, D. S. M.; Amarathunga, A. A. D.; Bakir, A.; McGoran, A. R.; Sivyer, D. B.; Reeve, C.A multitude of anthropogenic and industrial uses lead to the extensive dispersion of heavy metals in aquatic environments. The protracted presence and poisonous nature of heavy metals inflict negative impacts including organ malfunction and the inactivation of enzymes in aquatic organisms. The bottomdwelling mud crabs are frequently used as bioindicators for evaluating such heavy metal contamination in lagoons and estuaries. Therefore, the main emphasis of this study was on the amounts of heavy metals found in the meat of the Scylla serrata mud crab that lives in Negombo Lagoon, Sri Lanka. Due to their great sensitivity, mud crabs, bottom dwelling crustaceans that live in the bottom zones of lagoons, are frequently utilized as indicators for evaluating heavy metal contamination. Mud crab samples (n = 42) were randomly collected from the Negombo Lagoon from March to May 2023. Three replicates, 1 g each, of the flesh from each crab sample, were treated to acid digestion (conc. HNO3 and H2O2) and analysed separately using an atomic absorption spectrophotometer (AAS). Cu, Fe, Mn, and Zn were found to be the most common heavy metals in crab flesh based on the metal analysis. The amounts of Cd and Cr were not detectable. Zn (0.70 ± 0.24 mg/L) was the most prevalent heavy metal in the meat, followed by Mn (0.08 ± 0.07 mg/L), Cu (0.15 ± 0.12 mg/L), and Fe (0.46 ± 0.30 mg/L). The study's findings support the notion that the mud crabs living in the Negombo Lagoon have heavy metals in their meat. A recent study offers strong proof that heavy metals are present in mud crabs, a popular edible shellfish in Sri Lanka. The Negombo Lagoon's whole food chain may be affected by this contamination.Item Development of energy briquettes using Schleichera oleosa (Ceylon oak) wood, Oryza sativa (rice husk, rice straws and rice brain) and Saccharum officinarum (bagasse)(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Dulanjana, K. D. A.; Udawatta, M. M.; Prasad, P. D. A.; Bodaragama, T. P.; De Silva, D. S. M.Fossil fuels and firewood are the primary household energy sources in Sri Lanka. However, due to the economic crisis and the increasing inflation, fossil fuels are no longer a preferable choice. The use of firewood also has limitations, such as household air pollution due to the accumulation of smoke and toxic compounds causing immediate health issues. One of the solutions to this problem is the use of charcoal energy briquettes. Charcoal energy briquettes are compressed blocks made from pyrolyzed biomass residues. Burning these briquettes as an energy source, minimizes household air pollution and is energy efficient and cost-effective. Sri Lanka, a tropical agricultural country with significant vegetation growth, has great potential for developing carbonized charcoal briquettes from biomass energy sources such as ceyloan oak, rice husk, rice straws, bagasse and rice brain. In this study, Schleichera oleosa wood (Ceylon Oak) was used as the main component of the briquettes, as it was known to have a high calorific value. Ceylon Oak is used in furniture manufacturing, producing a large amount of sawdust waste, and this sawdust could be efficiently utilized to produce briquettes. Further, rice husk, rice straws, and bagasse with high ash content were used as additives to increase the burning time of the briquettes. Rice brain was used as the binding agent. During the study, the mixing ratios of the raw materials, pressure, and moisture content were varied to enhance the efficiency of the briquettes. Biomasses were pyrolyzed (300 °C, 1 h) to produce biochar. Different biochar mixtures (particle size < 2 mm) were compressed under different pressures (10 kPa - 60 kPa) using a newly innovated compressing machine to produce briquettes (OD: 4.15 cm, Height: 3.34 ±0.48 cm). They were dried in an oven (50 ℃) by varying the drying time (48 h, 72 h, 86 h, and 110 h) to change the moisture content. For each briquette produced, proximate analyses were carried out by measuring moisture (2% - 75%), volatile matter (20% - 36%), ash (10% - 30%), and fixed carbon content (38% - 70%). Calorific values were estimated based on the proximate analyses. The calorific values measured were in the range of 19,340 kJ kg-1 – 27,983 kJ kg-1 . Cooking efficiencies calculated were in the range of 2.5 kJ kg-1 - 27 kJ kg-1 exhibiting the potential of using these briquettes as a household energy source. According to this study, Schleichera oleosa and rice brain mixture 3:1 (w/w) ratio, showed the highest heating value and the highest cooking efficiency. The addition of rice husk, rice straw, and bagasse reduced the cooking efficiency of the briquettes. This study can be further extended to optimize other parameters of the briquettes (size, moisture content, compressed pressure and mixing ratios) to further enhance the cooking efficiency and burning time.Item Microplastic contamination in shrimps from the Negombo Lagoon- Sri Lanka(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Lawan, P. L. M. J. H.; De Silva, D. S. M.; Amarathunga, A. A. D.; McGoran, A.; Bakir, A.; Sivyer, D. B.Microplastics (MPs) are minute pieces of plastic debris that are smaller than 5 millimeters in size. They are created through the fragmentation or degradation of more oversized plastic items such as bottles, bags, and packaging materials. Additionally, MPs can also be intentionally manufactured for certain products like microbeads in personal care products. Microplastic pollution has turned into a severe global issue affecting freshwater systems, coastal regions, and oceans. These non-biodegradable materials have a detrimental impact on marine species and ecosystems, causing disruption to their feeding, breathing, and reproduction. The intention of this study was to identify and categorize the MPs present in shrimps from the Negombo lagoon, Sri Lanka, based on the type, shape, size, and color and to characterize the polymer composition of the identified MPs. Fresh samples of two species of shrimps, Penaeus monodon (n=25) and Penaeus indicus (n=95) were collected from the ten locations where the known habitats of shrimps in the Negombo lagoon and MPs were isolated by gastrointestinal tracts and gills by alkali digestion followed by vacuum filtration. Stereomicroscopy coupled with advanced microimaging and analyzing software was used for characterizing the isolated MPs. From those samples, 415 MPs were identified and characterized. The results showed that the average number of MPs per individual was higher in P. monodon (4.72 ± 2.72) compared to P. indicus (3.13 ± 2.04). The average number of MPs per gram of gut tissue was also higher in P. monodon (8.29 ± 4.63) compared to P. indicus (5.52 ± 3.78). Identified MPs were categorized into five size groups, 1000 μm. The majority of MPs identified were under the category of >1000 μm, and six color categories were observed, with blue being the most prevalent. The study identified two main types of MPs; fibers and fragments, and the predominant form of MPs was fiber (93.0%), with the remaining being fragments. The polymer composition of most of the MPs included polystyrene, polyamide, polyester, polypropylene, and rayons, as identified by µ-FTIR and ATR-FTIR studies.Item Pyrolysis of plastic waste into liquid fuel(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Uthpalani, P. G. I.; De Silva, D. S. M.; Weerasinghe, V. P. A.; Premachandra, J. K.The accumulation of plastic waste in the environment has emerged as a significant global concern. The versatile properties of plastics, such as low weight, low cost and durability which led to their widespread use as substituents for traditional materials like wood, metals, ceramics, and glasses. However, the improper handling and disposal of plastic waste have imposed negative consequences for the environment. The non-biodegradable nature of plastics makes them persist in the environment for extended periods, causing pollution and posing threats to ecosystems. Pyrolysis of plastic waste has been studied extensively in recent years as an effective solution, by exposing the plastic waste to high temperatures in an oxygen-free environment to decompose it into fuel oil, char, and gases. In this study, the waste of four types of plastics samples, low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP), and a mixture of these three types of plastics, were subjected to pyrolysis. Lab-scale, low-cost pyrolysis system was used to obtain liquid oils and herein, the non-condensed vapor was trapped into an organic solvent. Thermal pyrolysis or non-catalyzed pyrolysis resulted in a liquid yield of 65.64 ± 5.42 – 79.57 ± 1.66 wt.% at a temperature range of 340 – 360 ℃. Considering catalytic activity, high temperature stability, local availability, and abundance, four types of naturally available minerals were selected as potential catalysts for the pyrolysis of waste plastics. The mineral which resulted in the highest liquid yield was identified as the best-performing catalyst and used for further analysis. The catalyzed process resulted in an increased liquid yield of 71.79 ± 0.99 - 80.29 ± 1.76 wt.% at the temperature range of 290 – 320 ℃. The calorific value of the resulting oil in thermal and catalyzed pyrolysis processes were 10,850 -10,961 Kcal/kg and 10,556 - 11,473 Kcal/kg respectively. This reveals that the mineral selected is an ideal catalyst for pyrolysis of plastics and further indicates the quality enhancement of the fuel produced in catalyzed pyrolysis. Further, the fuel quality indicators; calorific values, density, kinematic viscosity, ash content, and water content of the resulting liquid oils under both catalyzed and uncatalyzed/thermal pyrolysis processes were significantly compatible with commercial grade diesel and kerosene fuel oils.Item The influence of substrates on the device performance of the TCO/CBD-CdS/ EDCdTe and TCO/CBD-CdS/CSS-CdTe solar cells(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Gajanayake, G. K. U. P.; Bandara, K. M. N. S.; De Silva, D. S. M.; Atapattu, H. Y. R.The development of cost-effective efficient photovoltaic cells is crucial for generating electricity with the most abundant solar energy to eliminate the energy crisis globally. At present, there is a growing interest in CdS/CdTe solar cells due to minimal material cost and easy and cost-effective methods of thin film deposition. The aim of this work is to investigate the influence of different transparent conducting oxide (TCO) substrates in superstrate configuration (glass/ITO:5 Ω/sq, glass/FTO:13 Ω/sq, and glass/FTO:7 Ω/sq) on the device performance of CdS/CdTe solar cells. Herein, chemical bath deposited CdS (CBD-CdS) layers were grown using 0.0333 mol/L Cd(CH3COO)2, 0.0667 mol/L CS(NH2)2, concentrated NH4OH and 1.0 mol/L NH4(CH3COO) at 90 ℃ for 55 min. Subsequently, the CdTe layers were deposited using electrodeposition (ED) and close spaced sublimation (CSS) techniques as required. For electrodeposition of CdTe layers, CdSO4 (1.0 mol/L) and TeO2 (1.0 mmol/L) precursors were used at pH of 2.3 and 65 ℃ and deposition was run for 3 hrs. The CSS-CdTe layers were developed by maintaining the substrate and source temperature at 580 °C and 640 °C, respectively, and the deposition proceeded for 25 min. at 7.9 Torr. The glass/TCO/CBD-CdS/ED-CdTe samples were treated with CdCl2, and glass/TCO/CBD-CdS/CSS-CdTe were undergone NP etching as suitable post-deposition treatments. The device fabrication was completed with the back contact formation (Cu/Au). The devices; glass/TCO/CBD-CdS/ED-CdTe/Cu/Au and glass/TCO/CBD-CdS/CSS-CdTe/Cu/Au prepared with FTO:13 Ω/sq delivered the highest efficiency of 5.7% (JSC = 19.2 mA/cm2, VOC = 0.672 V, FF = 44%) and 8.6% (JSC = 30.3 mA/cm2, VOC = 0.606 V, FF = 47%), respectively while the cells prepared with glass/ITO:5 Ω/sq delivered the lowest efficiency. Hence, the glass/FTO:13 Ω/sq substrate was recognized as the most appropriate substrate for the fabrication of CBDCdS/ ED-CdTe and CBD-CdS/CSS-CdTe solar cells. The resultant optical transmittance (over 80%, above 500 nm) and surface roughness (RMS roughness of bare FTO:13 Ω/sq was 12.49 nm, and FTO:13 Ω/sq/CBD-CdS was 10.15 nm) of CBD-CdS further confirmed the suitability aptness of the glass/FTO:13 Ω/sq substrate in CdS/CdTe based solar cell fabrication.Item Microplastics in selected offshore pelagic fish in Indian Ocean(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Jayarathna, N. K. D. M. P.; Walpita, C. N.; Amarathunga, A. A. D.; De Silva, D. S. M.; Sivyer, D. B.Microplastics (MPs) pollution in marine environment is an emerging threat to marine biota. Marine pelagic fish species such as tuna and tuna-like species caught during offshore fisheries in open seas, are known to be more commercially important and could be contaminated by MPs. As such, MPs could pose a risk to fish by themselves and to human health due to consumption of contaminated seafood. The present study was planned to investigate the MPs contamination of commercially important three pelagic fish species (Thunnus albacares, Katsuwonus pelamis, and Elagatis bipinnulata) caught from offshore fisheries using multiday boats from several locations of the Indian Ocean to fill the knowledge gap on MPs contamination of pelagic fish, especially in the Indian Ocean. Fish samples were collected from Beruwala, Galle, Panadura and Negombo fishery harbors in Sri Lanka, and the gastrointestinal tract (GIT) and gills were examined for possible MP contamination. A total of 40 samples belonging to three fish species were used for the study. The abundance and morphology (i.e. color, shape) of the MPs were assessed, and the polymer type of the MPs was investigated by using ATR-FTIR. Descriptive analysis was done by using IBM SPSS statistical version 26 and MS excel was used to calculate the percentages of MPs by color, shape and polymer type. There was a contamination of MPs in all three fish species. Nevertheless, 12.5% of E. bipinnulata and 21.7% of K. pelamis did not show MPs in analyzed tissues. T. albacares was found to have the greatest number of MPs (15±6 items individual-1). The morphology of the MPs found from the GIT and gills of all the three fish species were fibers (51%), followed by fragments (37%) and films (12%). In GIT, the most prominent color was blue in all the fish species. Moreover, the polymer types found belonged to three categories viz, thermoplastic elastomers (TPE), phenol formaldehyde resin (PF), and polyethylene copolymer (PE-Copolymer). Among them, the most prominent type of polymer was PF. PE-copolymer was found only in T. albacares. Therefore, continuous monitoring of marine environment and implementing stringent regulations are recommended to minimize plastic pollution in the Indian Ocean to protect both the marine ecosystem and humans.Item Microplastic contamination in selected commercial fish species in Negombo Lagoon, Sri Lanka(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Athukorala, A.; Amarathunga, A. A. D.; De Silva, D. S. M.; Bakir, A.; McGoran, A.; Sivyer, D. B.; De Silva, C. L. C. L.; Narangoda, S. R. C.Microplastics (MPs) act as physical anthropogenic pollutants and their ability to act as contaminant vectors in biological matrices has become a serious ecosystem and human health concern. The present study, for the first time, has screened and detected MPs in the gastrointestinal tract and gill of a select group of commonly consumed fish species from Negombo lagoon, Sri Lanka. Negombo lagoon is one of the most productive ecosystems in Sri Lanka. A total of 60 fish samples were investigated for the microplastic presence, abundance, and morphological types within the guts and gills of commercial fish consisting of seven (7) species: Siganus javus (SJ:n=5), Leiognathus splendens (LS: n=8), Leiognathus blochii (LB: n=5), Mugil cephalus (MC: n=19 ), Strongylura leiura (SL: n=10), Stolephorus indicus (SI: n=10), and Caranx heberi (CH: n=3) with different feeding habits and habitats. Samples were collected between July–December 2022. Fish gut content was screened for the presence of MPs using the alkaline digestion and density gradient separation technique (NaCl hypersaline solution) and examined using a stereomicroscope and micro-Fourier transform infrared spectrometer (m-FTIR). Microplastics, ranging from 0.05 to 4.80 mm, were found in the investigated fish species. Remarkably, this study revealed that 51.67% and 32.00 % of the fish samples contained microplastic in their guts and gills respectively. A total number of 67 MP particles (size < 5 mm) were found in the excised fish guts of the seven species. The most common morphology of microplastics discovered in fish guts was fragments, which accounted for 87.5% of all MPs present. The MP content in guts differed between species. Of that Mugil cephalus recorded the greatest amount of MP ingestion, with an average MP count of 2.68±0.23 items per individual in fish gut corresponding to an average abundance of 0.22±0.26 particles/g and 0.84 ±0.46 items per individual in gills corresponding to an average abundance of 0.41±0.68 particles/g. The majority of ingested particles were fragments (40.3%), followed by fibers (34.33%), films (19.40%), microbeads (4.48%), filament (2.29%), and no pellets were observed. In terms of colour, the most abundant were blue (58.20%), followed by green (13.43%), transparent particles (8.96%), yellow (7.46%), red (5.97%), black (2.98%), white, brown, pink (1.49%) were found in low number. The majority of MPs presented were identified by m-FTIR as particles of polypropylene and polyethylene (HDPE), rayon. The results are evident in the growing threat of MPs on biological matrices and ingested MPs in edible fish species present in the Negombo lagoon.