{
  "abstract": "The relationship between radionuclide contamination depth and subsurface intervention efficacy remains theoretically unconstrained. Conventional intuition assumes monotonic efficacy decline with depth due to increased transport pathlength and attenuation. To derive a mathematically rigorous, falsifiable relationship between depth‑dependent decay entropy and intervention efficacy in unsaturated soils, explicitly challenging the depth‑inverse efficacy paradigm. A coupled advection‑dispersion‑decay model (1‑D semi‑infinite domain, constant water flux, homogeneous porous medium) is formulated with a novel decay entropy metric – defined as the Shannon entropy of the radionuclide age distribution at depth . The intervention (step reduction of surface source by fraction at yields a time‑integrated efficacy , where is the instantaneous relative concentration reduction. Using the Green’s function solution for a flux boundary and the age probability density (with ), we prove that . For fixed mean age, the integral decreases monotonically with increasing entropy . Consequently: where depends on . This predicts higher efficacy at greater depth because broader age distributions (higher ) increase the fraction of radionuclides with ages – i.e., those already affected by the source reduction. Deeper contamination () is more responsive to surface‑applied interventions (e.g., capping, phytoremediation, chemical injection) than shallower contamination – exactly opposing conventional wisdom. A complete experimental design is provided (Section 2.6): 20 soil cores to 1 m, sectioned every 10 cm; compute from ¹³⁷Cs activity profile (λ = 2.3×10⁻² yr⁻¹); apply surface source‑reduction treatment; monitor dissolved ¹³⁷Cs at 10, 30, 60, 90 cm depth for two years; test positive correlation between and . Negative or null correlation falsifies the model. Two Testable Policy‑Relevant Predictions: (1) Depth‑integrated radionuclide activity is a superior predictor of remediation success than surface activity (2) Decay entropy gradients can zone sites for intervention priority (highest → highest efficacy). A complete, mathematically explicit, falsifiable theoretical framework linking decay entropy to intervention efficacy in unsaturated soils.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 1,
  "authors": [
    {
      "name": "Monday Sunday Adiaha"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/fxfxs6kbx7x5q.bib",
  "cited_by": 0,
  "doi": "10.4038/manatri.v2i2.3",
  "fulltext_url": null,
  "id": "fxfxs6kbx7x5q",
  "issns": [
    "3084-8601",
    "3084-8490"
  ],
  "landing_url": "https://hal.science/hal-05768107v1",
  "language": "en",
  "licence": "CC-BY-ND-4.0",
  "licence_label": "CC BY-ND 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "hal",
      "0.info"
    ],
    [
      "hal",
      "0.math"
    ],
    [
      "hal",
      "0.nlin"
    ],
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      "hal",
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      "hal",
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    ],
    [
      "openalex",
      "2306|Radioactive contamination and transfer"
    ]
  ],
  "openalex": "W7214673872",
  "pdf_url": "https://hal.science/hal-05768107/document",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-28",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/fxfxs6kbx7x5q.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:42Z",
      "native_id": "hal-05768107",
      "source": "hal",
      "url": "https://hal.science/hal-05768107v1"
    }
  ],
  "subjects": [
    {
      "field": "mathematics",
      "origin": "hal:0.math",
      "subfield": "general"
    },
    {
      "field": "physics",
      "origin": "hal:0.nlin",
      "subfield": "statistical-nonlinear"
    }
  ],
  "title": "Decay Entropy Scaling of Radionuclide Intervention Efficacy in Unsaturated Soil Profiles: A Theoretical Model",
  "title_text": "Decay Entropy Scaling of Radionuclide Intervention Efficacy in Unsaturated Soil Profiles: A Theoretical Model",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:17:42Z",
  "url": "https://research.draconitic.com/paper/fxfxs6kbx7x5q",
  "venue": "Manatri: Journal of Multi-Disciplinary Research",
  "versions": []
}