Biomonitoring of atmospheric particulate matter (PM) using magnetic properties of Ficus bengalensis tree leaves in Aizawl, Mizoram, North-East India

Particulate matter (PM) is one of the most harmful pollution components widely present in the environment. It has been demonstrated that magnetic measurement is an important means in PM pollution study through plant leaves. Plants species are found as effective biomonitors and may act as natural filters by trapping and retaining PM on their surfaces. In the present study, Ficus bengalensis tree leaves were sampled in the city area, peri-urban area and rural area, for the purpose of a magnetic study on atmospheric pollution in Aizawl City, Mizoram. Magnetic parameters [magnetic susceptibility (χ), anhysteretic remanent magnetization (ARM) and saturation isothermal remanent magnetization (SIRM)] of Ficus bengalensis tree leaves showed a significant variation range for three different study sites. Overall all values of magnetic parameters declined in the following sequence: city area > peri-urban area > rural area. Significant correlation of magnetic parameters with Fe, Pb and Cu revealed that leaf dust samples were dominated by multidomain, magnetite-like minerals. The results of the present study indicate that magnetic measurements of tree leaves are practicable for monitoring and determination of atmospheric pollution in Aizawl city. Biomonitoring of particulate pollution through magnetic properties of plant leaves is a rapid and inexpensive alternative to conventional atmospheric pollution monitoring. Moreover, bio-magnetic monitoring as an application of environmental geomagnetism may act as proxy for ambient PM pollution and may act as an eco-sustainable tool for environmental management.