[H-GG02] Dialogues on natural resources and environment between earth and social sciences

[HGG02-01] Preliminary magnetic biomonitoring of the spatial distribution of atmospheric particulate matter in the whole area of Toyama prefecture, Japan

*Kenta Ueki¹, Kazuo Kawasaki¹ (1.University of Toyama)

Keywords:Environmental magnetism, Atmospheric particulate matter, Human activities, Toyama

Magnetic biomonitoring techniques have been used to investigate the spatial distribution of atmospheric particulate matter. Environmental magnetic results are reported for the materials deposited on the Japanese flowering cherries (Prunus subgenus Cerasus) at 65 sites throughout Toyama prefecture in 2023. About three leaves were collected from each flowering cherry at a height of ~2.0 m from the ground, and then the collected leaves were directly put into 7 cm³ non-magnetic plastic cubes for room-temperature magnetic analyses. In addition, dust on the leaves was wiped off by quartz wool with ethanol and analyzed by low- temperature analyses. Room- and low-temperature magnetic analyses show measurable magnetic particles on the leaves at each site. It also indicates that the main magnetic minerals in the samples are single-domain partially oxidized magnetite and/or maghemite, and the magnetic mineralogy is likely consistent throughout the study area. Higher saturation isothermal remanent magnetization (SIRM) intensities are observed in urban areas, especially the northern part of Toyama City and Shinminato area in Imizu City, than in rural or mountain areas. The observed SIRM intensities were compared to the 500 m mesh-based population for 2015 in Toyama, and the SIRM intensities show a weak positive correlation with the population.These results indicate that human activity is one of the major sources of magnetic minerals within the atmospheric particulate matter.