Efficacy of pine needles as bioindicators of air pollution in Incheon, South Korea

Abstract

This study sought to analyze the particulate matter (PM) deposited on the surface of pine needles (Pinus densiflora) and pollutants within the needles and to investigate their utility as bioindicators. First-year needles of pines native to South Korea were collected at least 2 m above the ground. A total of four sampling points were selected: two parks around an industrial complex and two urban parks. After desorbing the PM deposited on the surface of the collected needles using ultrasonic waves, the PM and needles were classified; 21 metals, including Pb, contained in each medium were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS). Useful bioindicators for air-pollution monitoring among the PM deposited on the needles included Al, As, Be, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Ba, Bi, Cs, Li, Rb, Se, Sr, Tl, U, V, and Zn contents. In an analysis of elements identified in PM and needles, Al and Mn were determined to be equally useful as monitoring indicators across a wide area. Elements with high concentrations in pine needles due to PM deposition were As, Cu, Mn, Ni, Pb, Rb, and Sr. The pine needles themselves accounted for 99.95% of the combined mass of the needles and PM, with PM representing only 0.053% of the combined mass. Therefore, washing is expected to have little effect on the pollutant concentrations within the needles.