Occurrence of Microplastics in the Sediments Across Various Habitats within the Las Piñas Paranaque Wet Land Park (LPPWP)

Abstract

The Las Piñas–Parañaque Wetland Park is an ecotourism site and one of the two (2) remaining protected areas located in a highly urbanized city of Metro Manila, tagged as the “Last Coastal Frontier”. It holds the densest cover of mangrove within NCR, and is further recognized as an important migratory bird hotspot (Ramsar Site) or Wetland of International Importance. However, despite the area’s ecological importance, LPPWP, faces multiple threats like chronic water-quality issues, habitat destruction, and wildlife disturbance. In many coastal habitats like the LPPWP, the presence of microplastics has emerged as a significant environmental threat due to the increasing population in nearby communities and various unregulated pollution sources. This study aims to provide essential baseline information that can support and help in the updating of the protected area management plan for LPPWP, particularly in areas related to waste pollution, habitat conservation, and long-term ecological monitoring, considering that there is an information gap on the prevalence of existing microplastics within the area. In this study, microplastics were found in all of the three (3) sampling stations representing various habitats in LPPWP. Fragments were the most common type of microplastic observed, accounting for 50% of the total MP load. The study revealed presence of PP (Polypropylene), PE (Polyethylene), and PTFE (Polytetrafluoroethylene, often Teflon) type of polymer plastics. This finding indicates that the wetland is already being impacted by microplastic pollution, likely driven by continuous waste inflow from surrounding household communities and large industries. The origins of the microplastics across sedimentswere attributed to three (3) main sources: (a) linkage to waterways and river channels, (b) direct introduction by visitors, and (b) weathering breakdown of macro or meso plastics debris from nearby industrial areas. The result of the study highlights the urgent need for integrated management of plastic and targeted interventions for the protection of identified important habitats, as well as the existing biodiversity in the area. Some of the identified actions that can be taken into consideration of the management of LPPWP includes prioritizing strong waste-source reduction program; institutionalizing a Habitat Sediment Quality and Microplastics Monitoring Program through regular temporal sampling of sediments; strict implementation of RA 11898 Extended Producer Responsibility Act by integrating EPR-related requirements in business permit renewal of industries; promote waste diversion and recovery initiatives; and developing a GIS- based microplastic pollution zoning map.