Deitnf localized risk screening values of 22 elements in jieyang farmland by multifractal method: anchor point...

Jieyang farmland soils have been severely impacted by informal e-waste dismantling since the 1980s-1990s, with household workshops scattered across villages, employing primitive techniques (open burning, acid leaching) and engaging up to 80% of the local population. Despite this, toxic and strategic elements (Sb, Be, Th, U, Li) lack national screening values, creating a regulatory gap. Using 1330 topsoil samples, the multifractal method derived localized background and screening values for 22 elements, with eight national-standard heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, Zn) serving as anchors. Screening values aligned closely with GB 15618-2018 (deviations mostly ≤ ± 25%), while Cr and Ni thresholds were stricter, reflecting local protection. Background values matched iterative outlier elimination but required no data exclusion, proving robustness under non-normal distributions. Localized screening values for 14 unregulated elements were first proposed (e.g., Sb 3.552, Be 5.307, U 18.567, Li 52.409, Th 81.533 mg/kg). Spatial clusters of As, Sb, Li, and P coincided with mining areas, the Guiyu-Puning e-waste belt, and agricultural sources, validating the method. A three-dimensional risk system (exceedance, safety margin, fractal D₂) classified elements into high/medium/low risks, identifying Hg, Cd, As, Sb, Cu, Li, and Be as priority controls. This framework fills multi-element standard gaps in e-waste regions and offers transferable guidance for farmland management in similar workshop-affected areas.