Microplastics can act as carriers of heavy metals and may enter humans through ingestion and threaten human health. However, the bioaccessibility of heavy metals associated with microplastics and its implications for human health risk assessments are poorly understood. Therefore, in this study, four typical heavy metals (As(V), Cr(VI), Cd(II), and Pb(II)) and one typical microplastic (polyvinyl chloride, PVC) were chosen to estimate the human health risk of microplastic-associated heavy metals by incorporating bioaccessibility. Significant adsorption of heavy metals was observed with the following order for adsorption capacity: Pb(II) > Cr(VI) > Cd(II) > As(V); the efficiencies for desorption of these four heavy metals from PVC microplastics were all below 10%. The Fourier transform infrared spectroscopy results indicated that the functional groups on the surface of the virgin PVC microplastics did not play an important role in the capture process. Heavy metals in both gastric and small intestinal phases were prone to release from PVC microplastics when bioaccessibility was evaluated with the in vitro SBRC (Soluble Bioavailability Research Consortium) digestion model. In addition, Pb(II) bioaccessibility in the gastric phase was significantly higher than those in the other phases, while As(V), Cr(VI), and Cd(II) bioaccessibilities showed the opposite trend. After incorporating bioaccessibility adjustments, the noncarcinogenic hazards and carcinogenic risks determined were lower than those based on total metal contents. The individual hazard quotients (HQ) and carcinogenic risks (CR) for ingestion of these four heavy metals from PVC microplastics were all lower than the threshold values for adults and children. In summary, this study will provide a new view of the human health risks of heavy metals associated with microplastics. Supplementary Information The online version contains supplementary material available at 10.1007/s11356-022-20983-8.

Purpose In recent years, microplastic (MP) contamination has raised enormous concern. However, data on the influence of solid waste treatment systems on MP pollution around agricultural soil are lacking. This study investigated the distribution and characteristics of MPs in agricultural soil surrounding a solid waste treatment center in southeastern China. Materials and methods Fifty-seven agricultural topsoil samples around the solid waste treatment center were collected. The samples were pretreated by drying, flotation separation using NaCl solution, and digestion by H 2 O 2 . The abundance and morphological characteristics of MPs were determined by a microscope, followed by Raman spectroscopy analysis identified polymer types and SEM–EDS analysis observed surface morphology and the type of metals accumulated on the MPs. Results and discussion Soil MPs’ abundance ranged from 280 to 2360 items/kg, while a higher abundance of MPs was distributed in the downwind area. The < 1-mm MPs were dominant, and white fragment MPs were widely found. Polyethylene (52.86%) and polypropylene (27.14%) were the most common. Moreover, SEM–EDS images illustrated that MPs were significantly weathered and showed the uneven distribution of metal(loid) elements on the surface, implying that MPs may migrate as heavy metal vectors to threaten agroecosystem safety. Conclusions This study reveals the distribution and characteristics of MPs in agricultural soil surrounding a solid waste treatment center in southeastern China, as well as the potential source of soil MPs, and provides systematic data for further research on MP pollution in agricultural soil. Supplementary Information The online version contains supplementary material available at 10.1007/s11368-022-03341-6.

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