Occurrence of Microplastic Fragments in Pasig River

In an article published Lebreton et al 2017 in Nature Communication, Pasig River belongs to the top 20 polluters of plastics in world’s oceans dumping an estimated 3.88x10 4 tonnes of plastics annually. With these estimates, there is also the likelihood for microplastics to occur in the river. Microplastics are plastics particles with dimensions less than 5 mm. These are formed within bodies of water i.e. rivers by the forces shearing the large plastics. Also the UV from sunlight degrades plastic materials causing it to break into smaller, micro-sized or even nano-sized particles. Our group, reports the isolation of microplastic fragments in Pasig River near the Polytechnic University of the Philippines Main Campus in Sta. Mesa, Manila. The collection of floating particulates is by sieving the river water (flow rate = 0.31 m s -1 ) through a 0.35-mm mesh for 10 minutes. A total 25.7 m 3 river water was collected after three (3) sampling visits. Following collection, microplastics were isolated through a series of peroxide oxidation and sedimentation methods. Microplastic fragments was viewed and photographed under a compound microscope (40-100x). Thirty-four (34) microplastic fragments with lengths ranging from 0.56 – 4.58 mm was recorded. Microplastics were categorized as small and large with lengths of 1.16 ± 0.42 mm for small and 4.13 ± 0.37 mm for large respectively.