Sabiqah Tuan Anuar

Tropical estuaries are among the most under-sampled aquatic systems in the global microplastic literature, despite their role as transition zones for land-derived debris. We sampled 20 stations along the river–estuary continuum of Sungai Merbok, a mangrove-fringed estuary in Peninsular Malaysia, in May, July, September, and November 2024 (n = 80 surface-water samples). A 330 µm manta trawl filtered a mean of 17.07 ± 3.21 m³ per sample. We enumerated 1,971 microplastic particles in total (mean 1.46 ± 2.28 particles/m³, range 0.05–18.21) detected in every sample. Five mid-estuarine stations (SM 9, 11, 12, 14, 15) held 54.7% of all particles, and September concentrations ran 1.7 times higher than May and July combined. Of 547 particles analysed by FTIR, polyethylene (49.9%) and polypropylene (17.6%) together accounted for two-thirds of identified polymers, pointing to consumer packaging as the principal source. Polytetrafluoroethylene (PTFE) was the third most abundant polymer at 10.8%, well above the 0–2% typically reported for estuarine surface waters and raises the prospect of co-occurring PFAS contamination. Fragments dominated the morphological composition (66.8%), suggesting secondary breakdown of larger plastic items. Among environmental parameters, pH was the strongest single correlate of microplastic concentration (rs = -0.39, p < 0.001), followed by dissolved oxygen and salinity. A multiple regression model with five environmental predictors explained only 22% of log-concentration variance, showing that hydrodynamic processes drive spatial distribution rather than static water quality. These findings highlight two management priorities: extended producer responsibility for PE/PP packaging and pre-monsoon cleanups at mid-estuarine hotspots.

Tropical estuaries are among the most under-sampled aquatic systems in the global microplastic literature, despite their role as transition zones for land-derived debris. We sampled 20 stations along the river–estuary continuum of Sungai Merbok, a mangrove-fringed estuary in Peninsular Malaysia, in May, July, September, and November 2024 (n = 80 surface-water samples). A 330 µm manta trawl filtered a mean of 17.07 ± 3.21 m³ per sample. We enumerated 1,971 microplastic particles in total (mean 1.46 ± 2.28 particles/m³, range 0.05–18.21) detected in every sample. Five mid-estuarine stations (SM 9, 11, 12, 14, 15) held 54.7% of all particles, and September concentrations ran 1.7 times higher than May and July combined. Of 547 particles analysed by FTIR, polyethylene (49.9%) and polypropylene (17.6%) together accounted for two-thirds of identified polymers, pointing to consumer packaging as the principal source. Polytetrafluoroethylene (PTFE) was the third most abundant polymer at 10.8%, well above the 0–2% typically reported for estuarine surface waters and raises the prospect of co-occurring PFAS contamination. Fragments dominated the morphological composition (66.8%), suggesting secondary breakdown of larger plastic items. Among environmental parameters, pH was the strongest single correlate of microplastic concentration (rs = -0.39, p < 0.001), followed by dissolved oxygen and salinity. A multiple regression model with five environmental predictors explained only 22% of log-concentration variance, showing that hydrodynamic processes drive spatial distribution rather than static water quality. These findings highlight two management priorities: extended producer responsibility for PE/PP packaging and pre-monsoon cleanups at mid-estuarine hotspots.

This study successfully developed and evaluated a multi-step digestion protocol for the effective extraction and identification of microplastics (MPs) from human breast milk (HBM). The method combined hexane-mediated lipid removal, enzymatic digestion using Candida rugosa lipase at a milk-to-enzyme ratio of 20:1, protein digestion with potassium hydroxide (KOH) at 1:3 ratio, and oxidative treatment with hydrogen peroxide (H₂O₂) at 10% concentration. Ethanol was found essential for reducing sample viscosity, particularly post-saponification, thereby facilitating efficient filtration. Results showed that extended incubation times during enzymatic digestion notably enhanced lipid removal and improved clarity of the digestate, contributing to higher extraction efficiency. This protocol establishes a reproducible framework for reliable isolation and downstream spectroscopic identification of MPs in breast milk. Despite these advances, improvements in mechanical handling and contamination control are necessary to further enhance accuracy and consistency. The present findings contribute important methodological advancements to the field and support the urgent need for standardised, scalable protocols in monitoring neonatal exposure to environmental microplastic contaminants. Future work should expand on validation across diverse sample sets and explore correlations between MP presence and neonatal health outcomes.

Background and Aims: Previous studies have detected microplastics in bowel tissues, but have been limited by small sample sizes. Our study expanded the data collection from two countries at different time points (United States from 1993 to 1999 and Malaysia from 2023 to 2024) with the aim of comparing the physical and polymer characteristics of microplastics found in colorectal cancer samples. Materials and Methods: Microplastics were extracted from the tissues using a chemical digestion method of 10% potassium hydroxide, and examined under a stereomicroscope. Further surface morphology and polymeric composition were analyzed with a scanning electron microscope and micro‐Fourier transform infrared spectroscopy. Results: Microplastics were detected in all 50 samples (25 from the United States and 25 from Malaysia), with a higher abundance found in the Malaysian samples (32.2 ± 48.14 particles/g) compared to the American samples (25.00 ± 40.57 particles/g). Both population samples exhibited similar shapes, with fibers being the most abundant. American samples have longer microplastics (Category II = 501–1000 µm) than the Malaysian samples (Category I = < 500 µm). Both population samples exhibited surface roughness on their microplastics and similar polymer types including polyethylene (PE), polypropylene (PP), polyamide (PA) and polycarbonate (PC). Acrylonitrile butadiene styrene (ABS) was only observed in the American samples. Conclusion: Microplastics are detected in colorectal cancer samples of both populations collected from two different time points but with similar and also distinct physical and polymer characteristics.

Plastic debris is widely dispersed in the marine environment, posing a growing environmental concern due to microplastic pollution. Microplastics (less than 5 mm in size) form through plastic fragmentation and include fibers, fragments, films, pellets and foams. These particles may harm marine ecosystems, as ingestion of microplastics can disturb marine life. This study investigates and characterizes the presence of microplastics in commercial fish tissues from the South China Sea (SCS) and the Straits of Malacca (SOM). A total of 80 individuals from four species (Rastrelliger kanagurta – Indian mackerel, Atule mate – yellowtail scad, Decapterus punctatus – round scad, and Pampus argenteus – silver pomfret) were examined. The results showed a high abundance of fiber-shaped microplastic in all tissues samples (mean 8.95 particles per ind.). The presence of microplastics in samples collected from the SCS (10.28 particles per ind.) was higher than in those from the SOM (7.63 particles per ind.). Microplastic was found in higher concentrations in pelagic fish than in benthic fish. The dominant color of the microplastic was black, constituting 39% (SCS) and 45% (SOM). The smallest average size of microplastics in the fish tissues was 0.04 mm, which is from South China Sea fish. Scanning electron microscopy (SEM) images indicate different surface characteristics of the microplastics as a result of environmental exposure. Microplastics were associated with polyethylene (PE), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polycarbonate (PC), polyamide (PA), polypropylene (PP), polyester, rayon and poly(vinyl methyl ketone). The estimated daily intakes (EDIs) of microplastic through fish consumption are between 1.129 and 1.582 microplastics per capita. Overall, the data show that microplastics are widely distributed in commercial marine fish from Malaysian waters, which could contribute to human exposure through fish intake.