Microplastic accumulation in frozen mussels bought in Hong Kong

Wing Lam LAI

Research output: ThesisHonours Projects (HP)


Microplastics (< 5 mm) are ubiquitous in daily life and microplastic pollution has been a pressing environmental problem around the globe. Research studies had evidence that microplastics are present in a wide range of commercial seafood, putting human health in danger. The level of microplastic contamination in 50 frozen mussels of five origins bought in Hong Kong was investigated. The mussel samples were treated with potassium hydroxide (KOH) at 40°C for 36 – 48h to digest the organic matters in the soft tissues. The digested solutions were filter to obtain the microplastics on 0.6 μm pore size glass fibre filter papers. After drying, they were observed under a stereo microscope for visual identification of microplastics. 590 microplastic items were identified with a range of 0.06 mm to 17.06 mm sizes and mean of 1.18 ± 1.45 mm. The main form of plastic items were fibres and about 86% were smaller than 2 mm. The average abundance of microplastics in all origins was 11.80 ± 14.44 items individual⁻¹ and 1.42 ± 2.00 items g⁻¹ w. w. Canadian mussels contained the most abundant microplastics while Australian and Canadian mussels had the least. It was predicted that there were consistent microplastic contamination sources based on the shapes and colours of plastic items. No significant correlation was found between wet weight of mussels and microplastic abundance, which was contrary to previous research findings. Without FT-IR analysis, the detection of chemical composition of microplastics was not performed, which made ensuring the plastic nature and tracing of microplastic sources difficult. The annual intake of microplastics for local mussel consumers was calculated to be 507.93 microplastic items/year. It is advised that people should be more aware of microplastic consumption in diets. Actions should be taken to further investigate into potential health implications on long-term microplastic through food consumption.
Original languageEnglish
QualificationBachelor of Education (Honours)
  • CHEANG, Chi Chiu 蔣志超, Supervisor
Publication statusPublished - 2021


  • Honours Project (HP)
  • Bachelor of Education (Honours) (Science) (Five-year Full-time)
  • Programme code: A5B085
  • Course code: SCG4025


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