Application of biomonitoring of air-suspended metal pollutants and enrichment factor analysis for source identification of metals from roadside in Phitsanulok municipality, Thailand

Biomonitoring of air-suspended metallic pollutants using plants is an efficient and reliable technique.The enrichment factor (EF) is used to define how much the presence of metal elements in a sample is raised relative to the average natural abundance because of anthropogenic activities.This study performed a leaf-level holistic analysis of dust deposition on Thai bungor leaves.The EF was used for metal discrimination in terms of the natural and anthropogenic inputs to the system.Samples were exposed at ten roadside areas in Phitsanulok Municipality.Samples were collected for 15 days/month in March (dry season) and July (rainy season) 2022.Samples were analyzed for the content of 15 metals (Al, Ba, Cd, Cr, Cu, Fe, K, Mg, Na, Ni, Pb, Sb, Sn, V, and Zn) by Inductively Coupled Plasma-Mass Spectrometer (ICP-MS).The results showed that Al, Na, Fe, and K constitute the major proportion of air pollutants.V was not found in either season.By EF analysis, Ba, K, and Na enrichment was minor (1 < EF 3), and Mg and Fe were moderately enriched (3 < EF 5), indicating that elements are influenced by human activities in addition to soil sources.Cr enrichment was severe (10 < EF 25), and the enrichment of Cd, Cu, Ni, Pb, Sb, Si, Sn, and Zn by anthropogenic activity was extremely severe (EF > 50).This research will serve as a guideline for planning air quality management in Phitsanulok Municipality.