Microplastics assessment in Arabian Sea fishes: accumulation, characterization, and method development

Area of Science:

• Marine Biology
• Environmental Science
• Polymer Science

Background:

• Plastic pollution is a global issue, with microplastics entering aquatic ecosystems and being ingested by marine life.
• Understanding microplastic accumulation and polymer types is crucial for source tracing and environmental risk assessment.

Purpose of the Study:

• To investigate microplastic accumulation in fish from the Karachi coastal area.
• To evaluate the efficiency of different digestion protocols for microplastic extraction.
• To characterize the polymers using Fourier-transform infrared (FTIR) spectroscopy.

Main Methods:

• Guts of five fish species were analyzed for microplastic content.
• Potassium hydroxide (KOH) and hydrogen peroxide digestion protocols were tested for efficiency.
• Fourier-transform infrared (FTIR) spectroscopy was used for polymer identification.

Main Results:

• 87% of fish analyzed contained microplastics, with an average of 1154 microplastics found.
• Otolithes ruber had the highest average microplastic load (54 MPs/fish).
• Microfibers were the most common shape, and polyethylene and polypropylene were the dominant polymer types.

Conclusions:

• This study confirms the presence of microplastics, primarily polyethylene and polypropylene, in marine fish from Pakistan's Karachi coast.
• Effective digestion protocols using KOH and hydrogen peroxide were identified.
• The findings highlight the pervasive nature of plastic pollution in marine environments.