Magnetic Susceptibility of Spider Webs and Dust: Preliminary Study in Wrocław, Poland

Previous studies have proven that spider webs can be a reliable tool for magnetic biomonitoring. This study aims to present the magnetic susceptibility values of urban road dust (URD) settled indoors and outdoors, and compare these values with spider webs exposed to indoor and outdoor pollutants, and therefore to discuss their potential environmental implications. The webs of Eratigena atrica, Tegenaria ferruginea, and Agelena labyrinthica (Agelenidae) spiders from outdoor and indoor study sites were investigated, along with dust deposited on filters (indoors) and dust collected from the surrounding neighborhood (outdoors). Magnetic measurements revealed elevated levels of magnetic pollutants at all investigated sites in the city of Wrocław. The indoor/outdoor ratios of mass-specific magnetic susceptibility for the studied samples suggested a prevalence of indoor pollution sources at two of the sites (prosthetic laboratory and environmental science laboratory), whereas the third site (tenement house neighborhood) was dominated by material that presumably originated from predominantly outdoor sources. The indoor/outdoor ratios of magnetic susceptibility for the investigated matrices at the examined sites were highly comparable, which is promising for the utilization of spider webs in magnetic monitoring.