Microplastics in the Road Dust of Iligan City, the Philippines

Microplastic (MP) pollution in the environment has become an increasingly common problem in the Philippines. Despite its growing evidence in biotic and abiotic ecosystems in the country, there is a dearth of knowledge of its deposition in road dust. MPs can be suspended in the atmosphere and may originate from road dust through point sources – prompting respiratory tract infections and countless other health problems when humans breathe. These notions lead us to investigate the presence of MPs in road dust in Iligan City, the Philippines. Specifically, three stations were assessed within the city's urban streets – namely Brgy. Tibanga, Brgy. Poblacion, and Brgy. Palao. In each station, sampling was done by placement of three quadrats in both right- and left-hand traffic of the road. The road dust from each quadrat was collected and filtrated using the sieving method, which was categorized according to particle size. The samples were then digested in a solution and filtrated using a vacuum system in a secured laboratory. The suspected road dust MPs (RDMPs) were isolated through microscopy analysis, and their maximum dimension was measured. Each suspected RDMP was then analyzed using Fourier transform infrared spectrometry analysis to confirm their polymer types. Herein, the results confirm that the RDMPs particle size ranged from ≤ 100 μm to ≤ 5000 μm. Their most dominant characteristics were being a fibrous type of materials and blue color – equivalent to 90.7%. Additionally, their polymer types are mostly polyester (58.3%) – followed by ethylene propylene (25%), ethylene vinyl acetate (8.3%), and polyacrylamide (8.3%). Therefore, these results strongly indicate that RDMPs can in fact be found in the streets of Iligan City. This is also the first evidence in the Philippines that highly recommends that there is a need to further understand the extent of RDMP pollution in the country.