Microplastics, due to their surface properties, porosity and electrostatic interactions have a high affinity for cations sorption from the aqueous phase. As soil is a complex matrix, interactions between microplastics, soil constituents and heavy metals (HM) may modify the soil microenvironment for heavy metal mobilization/immobilization processes. In order to better understand the problem, three commonly found forms of microplastics in soil (fibers, fragments and microbeads) were mixed with Cu²⁺- or Pb²⁺-contaminated soil and incubated at 22 °C for 180 days. In soil samples pH and the content of water and acid exchangeable species of metals were analyzed. The results of this study showed that the presence of microplastics in HM-contaminated soil affected metal speciation, increasing the amount of easily exchangeable and potentially bioavailable forms of Cu²⁺ or Pb²⁺ in the tested soil. Soil pH also increased, confirming that microplastic particles affect soil properties relevant to the sorption/desorption process of metal cations. Overall, the smallest microplastic particles (≤1 mm), such as fibers or glitter microbeads, had a greater impact on the change in the sorption and desorption conditions of metals in tested soil than larger particles. The findings of our study show that microplastic form, shape and size should be considered as important factors that influence the soil properties and mobility of heavy metals in soil.

With the increasing amounts of microplastic (MP) deposited in soil from various agricultural activities, crop plants can become an important source of MP in food products. The last three years of studies gave enough evidence showing that plastic in the form of nanoparticles (<100 nm) can be taken up by the root system and transferred to aboveground plant parts. Furthermore, the presence of microplastic in soil affects plant growth disturbing metabolic processes in plants, thus reducing yields and crop quality. Some of the adverse effects of microplastic on plants have been already described in the meta-analysis; however, this review provides a comprehensive overview of the latest findings about possible adverse effects and risks related to wide microplastic occurrence in soil on crop production safety, including topics related to changes of pesticides behavior and plant pathogen spreading under the presence MP and possibly threaten to human health.

Microplastic (MP) contamination in soil is an emerging environmental concern, influencing the mobility and bioavailability of heavy metals (HMs). This study investigates how different MP types (PP, PS, PVC, HDPE, LDPE, PES, and PET-Glitter) affect HM behavior in soil, focusing on sorption/desorption, and the extraction efficiency of Pb, Cu, Co, Ni, Cr, and Cd. Soil samples incubated with MPs showed significant pH increases, particularly with PES and HDPE at 0.8 and 0.6 pH units, respectively. The extraction experiments using 0.05 M EDTA and 0.01 M CaCl₂ revealed that MPs altered metal bioavailability—with HDPE reducing Pb mobility by 15%—and increased Cd and Co mobility by 10–20%. The batch sorption tests confirmed higher Pb adsorption onto HDPE but decreased Cd and Co sorption compared to control soils without MP. These findings demonstrate that MPs act as additional sorption sites, modifying metal speciation and availability, which has critical implications for soil health, agricultural sustainability, and remediation strategies. However, results may vary based on soil type, MP aging, and environmental conditions, indicating the need for further long-term field studies. This research provides valuable insights into the complex interactions between MPs, heavy metals, and soil systems, contributing to a better understanding of pollution dynamics and risk assessment in contaminated environments.

This study investigates how different types of microplastics (MPs)—fibers, glitter, plastic bags, and plastic bottles—influence heavy metal uptake in lettuce (Lactuca sativa L.), a commonly consumed leafy vegetable. A controlled eight-week pot experiment was conducted in a greenhouse using contaminated loamy sand soil (polluted with Cd, Pb, Cu, and other metals) collected from a smelter-impacted area. Microplastics were added at a concentration of 70–80 mg/kg, and lettuce seedlings were grown under phytotron conditions (22 ± 2 °C, 60 ± 5% RH, 16 h light/8 h dark) without fertilizers or external contaminants. Plant roots and shoots were harvested, and heavy metals were analyzed via MP-AES and ICP-MS. The results showed that MPs altered heavy metal mobility, bioavailability, and plant uptake. Copper accumulation in leaves decreased substantially across MP treatments, from 80.84 mg/kg in the control to 26.35 mg/kg (glitter), whereas lead and cadmium concentrations increased significantly in roots under fiber and glitter exposure (Pb increased from 12.13 mg/kg to 33.57 mg/kg and Cd from 1.70 mg/kg to 2.05 mg/kg in fiber treatment). Cobalt accumulation in leaves increased under the plastic bag treatment, indicating MP-specific metal interactions. Root growth was also affected, with fibers promoting elongation and plastic bottles restricting it. Sequential extraction revealed that MPs modified metal partitioning in soil, with Pb and Ni more strongly retained in stable fractions under some treatments. Observed trends in soil pH and organic matter content were associated with changes in metal mobility, highlighting the potential role of soil properties in mediating microplastic–metal interactions. These findings highlight the role of MPs as mediators of heavy metal transport in crops and underscore the need for clear regulatory guidelines that limit microplastic contamination in agricultural soils and promote routine monitoring to safeguard food safety and crop health.