Preliminary Detection of Suspected Microplastics in Soil at Varying Distances from a Dumpsite Using the Hot Needle Test

Microplastic pollution has become an environmental concern because of its persistence and accumulation in ecosystems, including soil. This study assessed the presence of suspected microplastic particles in soil collected at different distances from a dumpsite in Barangay Makabaklay, Gapan City, Nueva Ecija, using low-cost screening methods such as sieving, density separation with sodium chloride (NaCl) solution, and the hot needle test. Soil samples were collected at distances of 0.5 m, 3 m, and 10 m from the dumpsite at a depth of 0.30 m, with two replicates per location. Samples were air-dried, sieved using a 60-mesh (0.3 mm) sieve, and subjected to density separation to isolate lighter particles. Suspected particles were analyzed using the hot needle test, where melting or deformation indicated possible plastic composition. Results showed positive responses in samples from 0.5 m and 3 m, while no positive response was observed at 10 m. Findings suggest that suspected microplastic occurrence decreases as distance from the dumpsite increases. The study concludes that the hot needle test is a practical and cost-effective preliminary screening method for suspected microplastics in soil.