uptake of potentially toxic elements in microplastic-contaminated soils: a controlled laboratory study using eisenia fetida

Background: earthworms are known to respond quickly to various environmental stressors. the present study aimed to investigate the relationship between varying levels of tire-derived microplastic (tmp) exposure and the accumulation of specific heavy metals in the earthworm eisenia fetida.methods: we assessed the accumulation of arsenic (as), cadmium (cd), chromium (cr), tin (sn), aluminum (al), lead (pb), zinc (zn), and molybdenum (mo) in eisenia fetida through a 14-day controlled exposure to tmp concentrations of 0, 10, 50, 100, and 200 mg/g dry artificial soil, with three replications. results: the accumulation of cr, sn, al, pb, zn, and mo increased significantly with tmp concentrations exceeding 100 mg/g. the concentration of cd remained statistically similar in tmp concentrations above 50 mg/g, while a significant increase in zn concentration was observed at tmp levels higher than 100 mg/g. the correlation coefficients between potentially toxic elements (ptes) concentration in the species and inhabited soil were negative and statistically significant for cd (p-value < 0.05), al (p-value < 0.01), and mo (p-value < 0.05), suggesting a depletion of ptes from the soil as the earthworms accumulated higher concentrations.  maximum levels reached 130.44 ± 4.43 μg/l for sn, 2.46 ± 1.74 mg/l for zn, and 0.057 ± 0.006 mg/l for cr in the 200 mg tmp exposures.conclusion: this study used artificial soil samples, and the impact of soil physicochemical characteristics on the mobility and bioavailability of mp-associated ptes remains an area open for future investigation.