Authors : Appiah, Mark Kubi

Volume/Issue : Volume 11 - 2026, Issue 3 - March

Google Scholar : https://tinyurl.com/5y9t2tvf

Scribd : https://tinyurl.com/ycxafbz6

DOI : https://doi.org/10.38124/ijisrt/26mar037

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Abstract : Environmental exposure to polycyclic aromatic hydrocarbons (PAHs) and potentially toxic elements (PTEs) presents persistent human health risks due to their carcinogenicity, bioaccumulation potential, and multi-pathway toxicity. Although conventional risk assessment frameworks quantify carcinogenic risk (Incremental Lifetime Cancer Risk, ILCR) and non-carcinogenic hazard (Hazard Quotient, HQ; Hazard Index, HI), they often present outputs separately and rely on deterministic point estimates that obscure uncertainty. This review develops and systematizes a unified Organism Exposure & Risk Index (OERI), a transparent and dimensionless composite screening metric that integrates inhalation, dermal, ingestion, and injection pathways for both PAHs (via benzo[a]pyrene toxic equivalency, BaP-TEQ) and PTEs. The framework synthesizes established chronic daily intake (CDI) equations, slope factor (SF) based carcinogenic modeling under the linear no-threshold assumption, and reference dose (RfD) threshold toxicology into a normalized cumulative index. OERI incorporates regulatory benchmarks to harmonize ILCR and HI scales and allows flexible weighting of carcinogenic and non-carcinogenic endpoints. A probabilistic Monte Carlo extension is presented to propagate variability and uncertainty across exposure factors, generating risk distributions, exceedance probabilities, and sensitivity diagnostics. The approach aligns with contemporary regulatory guidance advocating uncertainty-informed cumulative risk assessment. OERI functions as a screening-level decision-support tool that enhances transparency, comparability, and pathway attribution while preserving component-level regulatory interpretation. This integrative model provides a defensible methodological bridge between environmental monitoring data, toxicological scaling, and risk-informed environmental health decision-making.

Keywords : Organism Exposure & Risk Index (OERI); Polycyclic Aromatic Hydrocarbons (PAHs); Potentially Toxic Elements (PTEs); Chronic Daily Intake (CDI); Incremental Lifetime Cancer Risk (ILCR); Hazard Quotient (HQ); Monte Carlo Simulation; Cumulative Risk Assessment; Toxic Equivalency Factors (TEFs); Environmental Health Risk Modeling.

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