Laboratory experiments that assess microplastic (MP) impact on the terrestrial environment require information on common soil MP concentrations. We reviewed item numbers and mass concentrations recorded in 23 studies, with 223 sampling sites in total with respect to the underlying entry pathways, land uses and vicinities. Common values included amounts of up to 13 000 items kg⁻¹ and 4.5  mg kg⁻¹ dry soil. Based on the collected data, we identified problems in past field studies.