Assessment of Macroplastic Litter on the Coastal Seabeds of Sultan Naga Dimaporo, Lanao Del Norte, Philippines

Plastic pollution is an arising problem of our generation. Tons of plastics are globally produced affecting different coastal ecosystems. Plastics pile and end up in coastal areas, at the ocean surface, and in the coastal seabed. Almost 70% of plastics made are known to eventually sink in water, and it is suspected that ever-increasing amounts of plastics are accumulating in seabed sediments. However, there are limited studies on macroplastics in coastal seabeds in the different coastal ecosystems in the Philippines. This study aims to determine the prevalence, types, and density of macroplastic litters in the coastal seabed of Sultan Naga Dimaporo (SND), Lanao del Norte. A 100-m transect line with four quadrats measuring 5 m x 5 m, was delineated parallel to the seabed at the beaches of Barangay Pikalawag, Dabliston, Koreo and Sugod. Results revealed that all four sites were contaminated with plastic litter in which 55% were from Pikalawag, a residential area, 16% from Dabliston, a mangrove area, 15% from Sugod, a beach/tourism area, and 14% from Koreo, a non-residential area. The plastic density was 1.32 items/m2 for Pikalawag, and 0.32 to 0.37 items/m2 for the other areas. The waste collected was primarily food packaging (17%), plastic fragments (16%), and plastic bags (11%). The highest polymer type was LDPE (40%) followed by both multilayers (13%) and PET (13%). Based on the clean coast-index, Pikalawag can be categorized as extremely dirty while the other three sites were moderately clean. Overall, this study showed how the prevalence and composition of plastic litter vary in different coastal seabeds in SND, Lanao del Norte.