Assessment of microplastics in Sto. Niño and Sta. Elena section of Marikina river, Marikina city, Philippines/
Jordan Provido, Kate Angeline E. Labitag, John Wendell B. Ambrosio, Bryan Ivan M. Reyes .--
- Manila: Technological University of the Philippines, 2024.
- ix, 99pages: 29cm. +1 CD-ROM (4 3/4in.)
Thesis (undergraduate)
College of Science .--
Includes bibliography:
Microplastics (<5mm) are plastic debris originating from primary and secondary sources. The Philippines is considered a top contributor of plastics globally, however, there is still limited research about microplastics in the country, particularly in freshwater such as rivers. Rivers serve as one of the major pathways of land-based sources of microplastics that end up in the ocean. In this study, microplastic abundance and characteristics were assessed in the Sto. Nino and Sta. Elena section of the Marikina River, Philippines during wet and dry season. Surface water samples were collected using a bucket and Van Veen grab for sediments. Microplastics from the samples were extracted through 10% KOH digestion and floatation using 30% NaCl. Morphological characteristics were determined using a compound microscope while polymer types were identified via the FTIR-ATR method. The mean abundance of microplastic was 66.77 ± 55.95 particles/m3 and 17.33 ± 14.81 particles/kg in surface water and sediments, respectively. A significant difference was not found between abundance and seasons in surface water (p>0.05); however, a significant difference was shown between abundance and seasons in sediments (p<0.05). The majority of the microplastics were categorized under 1<5.00 mm in surface water and 500–<1000μm in sediments. Blue and white were the most abundant colors in surface water while red and white were in sediments. Fiber/line and fragments were the most dominant shapes. The study identified nine polymer types in which polyethylene (PE) and polypropylene (PP) were the most dominant across all seasons. There was a very low negative correlation between microplastic abundance and pH, while there was a very low positive correlation between conductivity and salinity.