POTENTIAL EFFECTS OF ENVIRONMENTAL MICROPLASTICS ON PHYTOREMEDIATION OF Cu, Mn and Sr FROM SERBIAN URBAN SOILS

Abstract

Microplastics (MPs) are omnipresent contaminants, becoming a global environmental and ecological concern. MPs and potentially toxic elements (PTEs) often coexist in soil. However, the impacts of MPs on soil-plant systems and phytoremediation of PTEs are still poorly acknowledged. This field study investigated MPs prevalence in four Serbian cities and evaluated potential impacts on the uptake of PTEs (Cu, Mn, and Sr) by bioindicator Capsella bursa-pastoris L. Medik. MPs isolation from soil samples was conducted using the optimized density separation method. Total (aqua regia) and phytoavailable (EDTA) PTEs fractions in soils were analyzed alongside the concentrations in plant roots and shoots. Soils from Bor contained the highest total concentrations of Cu (516,14 µg g^-1), Mn (553,46 µg g^-1) and Sr (173,69 g^-1). Igeo index exhibited moderate to heavy soil contamination. Up to 50.7% of Cu_total, 34.4% of Mn_total, and 27.3% of Sr_total were extracted in the phytoavailable pool. After the uptake, C. bursa-pastoris predominantly translocated PTEs to the aboveground parts, demonstrating phytoextraction as the prevailing strategy. PCA analysis indicated clear distinction based on sampling sites and the formation of separate clusters belonging to four cities. Moreover, Spearman correlation analysis revealed the significant interconnection among MPs and PTEs mobility in the soil-plant system. MPs positively correlated to Cu phytoavailable fraction in soils (ρ=+0.49) and with Cu content in shoots (ρ=+0.56), suggesting that it might stimulate Cu availability and improve the efficiency of uptake by plant. These findings provide insights into MPs-PTEs interactions, thereby contributing to a better understanding of potential environmental impacts.