Quantification and characterisation of microplastics in fish and surface water at Melayu River, Johor

Abstract

Microplastics are plastic particles (< 5 mm) found in the environment that can be ingested by animals and transferred up in the trophic level. The study was conducted through sample collection, digestion of gastrointestinal (GI) tracts of fish, density separation using NaCl, filtration, microscopy, and ATR-FTIR Spectroscopy. The amount of ingested microplastics by Melayu River fish samples was: Gray Eel-Catfish (3.92 ± 4.17 particles/individual) > Sagor Catfish (2.00 ± 1.41 particles/individual) > Spotted Sicklefish (2.00 ± 0.00 particles/individual). The trend of microplastics by month in water samples was Mar-20 (2.89 ± 1.36 particles/L) > Feb-20 (1.33 ± 1.00 particle/L) and Jan-20 (1.00 ± 0.87 particle/L). Microplastics were mostly in the class size 0 µm – 0.50 µm. In the fish samples, fibres were found to be dominant. In water samples, films were dominant. Ingestion of microplastics by colour was ranked as blue > black > red > yellow in fish samples whereas microplastics' colour in water samples was ranked as blue > red > black > translucent > green. Therefore, it is concluded that the abundance of blue microplastics in fish samples was due to the common blue plastics used by the locals. The identified microplastics were of polyethylene terephthalate (PET) and polyethene (PE) origins.