Microplastics in soil and groundwater along an urban river in Bauru (SP, Brazil)

The occurrence of microplastics (MPs) in environmental matrices has gained such importance that it frequently appears in daily news, even in unexpected places like human organs or remote areas of the planet. Measuring their concentration in the subsurface is essential for mapping their occurrence and devising strategies to minimize human exposure to their harmful effects. In this study, soil and groundwater samples were collected from three points in Bauru (SP, Brazil), along the banks of an urban river. The samples were processed in the laboratory and analyzed for morphological (size, volume, color, and shape) and chemical (µRaman) characterization. MPs were present in all samples, with fibers predominating in both soil and groundwater. In both matrices, most MPs were smaller than 1 mm. In the soil samples, 9099 particles/kg dw of soil were found at point S1, 3249 at S2, and 4154 at S3. In the water samples, there were 7250 particles/m³ at P1 and 8000 at P2. The total volume of particles at point S1 was 2.38 mm³/kg dw of soil, 1.29 mm³/kg dw at S2, and 1.73 mm³/kg dw at S3. The total volume of microplastics in the water was estimated at 1.3 mm³/m³ at P1 and 1.5 mm³/m³ at P2. Most particles were polyester (in water) and PET (in soil). The drug loprazolam was found associated with one of the fibers. The total volume of MPs in each sample correlated with the number of particles found, aligning with those with the largest volume. The association of one of the fibers with a drug indicates the ability of MPs to adsorb and transport other contaminants. Also see: https://micro2024.sciencesconf.org/558152/document