1662 stage is characterized by specific sources of contamination, substances of concern, receptors, and exposure pathways, and therefore requires a tailored assessment approach. This staged framework allows evaluation not only of areas subject to closure measures, but also of areas that, although not included in the original closure plan, may require additional rehabilitation or remediation to enable safe future land uses. Recent literature consistently indicates that risk is a function of land use. Early definition of post-closure land use determines exposure pathways, relevant receptors, and closure performance objectives (ICMM, 2025). The ICMM explicitly addresses this relationship through dedicated tools —such as Screening Alternatives for Repurposing— designed to align closure vision, objectives, and risk assessment with reasonably anticipated future uses (ICMM, 2025). The risk assessment methodology applied in this work comprises four main phases: 1. Problem formulation 2. Contamination characterization 3. Toxicity and exposure assessment 4. Risk characterization 2.1 Problem formulation In this phase, the objectives and scope of the risk assessment are defined, and a preliminary conceptual site model is developed. The model integrates sources of contamination, contaminant transport mechanisms, exposure routes, and potential receptors across different levels of biological organization. Figures 1 and 2 present examples of Conceptual Site Models for closure and future land‑use scenarios, respectively. A comprehensive review of background information is conducted to identify the key elements of the conceptual model and to determine the substances of interest to be evaluated.
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