Novel insight into deriving remediation goals of arsenic contaminated sites with multi-media-equivalent dose and local exposure parameters

The remediation goal (RG) for arsenic (As) calculated by the traditional method is approximately 0.45 mg·kg^-1, significantly lower than the background values. This poses significant challenges for the management of As-contaminated sites. The present study focused on a typical glassworks site with an As contamination level of up to 298 mg·kg^-1, predominantly existing as As (III), with a carcinogenic risk level as high as 8.6 × 10^-5. We developed a novel method known as multi-media-equivalent dose (MMED), incorporating local exposure parameters, and investigated the impacts of site-specific bioaccessibility (from 6.9% to 51.5%) on the results. The RG of arsenic calculated via MMED was 34.4 mg·kg^-1 and 54 mg·kg^-1 when bioaccessibility was considered. Integrating with five exposure parameters across 31 provinces, the provincial remediation goals (PRGs) ranged from 15.1 to 31.7 mg·kg^-1. The RG calculated using the new method were more aligned with the practical conditions of managing As-contaminated sites, with potential for broader implementation across various provinces.