Spatial modeling of magnetic monitoring data of soils and epiphytic mosses

Abstract

The aim of the study was to perform spatial modeling of the magnetic enhancement coefficient of soils and epiphytic mosses in an urbanized area.

Location and time of the study. Soil and epiphytic mosses samples were collected in June 2024 residential development area of the Motovilikha district of Perm (57°59ʹ04,80ʺ N and 56°15ʹ44,45ʺ E; 58°03ʹ02,52ʺ N and 56°19ʹ09,54ʺ E).

Methods. Laboratory studies included sample preparation and volumetric magnetic susceptibility measurements. Cartographic data were generated using point datasets in QGIS and SAGA GIS. The study included interpolation using the geostatistical method of ordinary kriging (Smart Map QGIS module) and reclassification of raster layers of absolute values into magnetic enhancement coefficient values using the QGIS "raster calculator" tool. To analyze the feature space structure (taking into account the distance to the source of highly magnetic compounds – PJSC Motovilikha Plants) of the magnetic enhancement factor soils and epiphytic mosses) kernel density estimation was used using the pandas and matplotlib libraries of the Python programming language.

Results. The soil cover was characterized by a wide range of the obtained magnetic susceptibility values (from 0,120 to 19,310), whereas the susceptibility of epiphytic mosses was significantly lower, the values being distributed more evenly (from 0,01 to 1,13). The first decile of the distribution was used as the background value of magnetic susceptibility; it was 0,558 for soils and 0,110 for epiphytic mosses. The minimum values for soils and epiphytic mosses were typical for squares and courtyards, confirming their role as relatively clean zones with low accumulation of highly magnetic particles. The maximum values of the volumetric magnetic susceptibility were typical for the vicinity of the industrial zone and the private sector, due to the proximity to PJSC Motovilikha Plants. To display the magnetic enhancement factorspatial distribution, pixel values were classified according to a threshold scale based on the fold excess of the background level.

Conclusions. The conducted research substantiated the use of the magnetic enhancement factor for mapping the ecological and magnetic state of urbanized areas. Magnetic enhancement factor  maps of soils and epiphytic mosses, compared with the maps of volumetric magnetic susceptibility values, showed comparable values for the accumulation levels of man-made particles. The use of magnetic enhancement factor to map magnetometric survey results allowed the relative assessment of the man-made magnetic particles accumulation and comparable pollution gradations ("no enrichment," "low," "medium," "high," and "very high") for both soils and epiphytic mosses. Using this approach to compare the spatial distribution of magnetic susceptibility study results in soils and epiphytic mosses represents a novel approach for biomonitoring in the  urbanized areas of Russia. In the Motovilikha district of Perm, the leading factor is the distance from the industrial enterprise, which determines the zone of transport and accumulation of man-made magnetic particles.