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    Labreador / Ecotoxicology

    Target Hazard Quotient Calculator

    Calculate non-cancer dietary screening risk from metal concentrations, food intake and body weight. Labreador's Ecotoxicology Risk Assessment supports individual metals, complete-panel HI, batch tables and probabilistic analysis.

    Open Risk AssessmentMethods and references

    Free · No account · Local web calculations · Research use only

    Worked example

    Illustrative cadmium scenario: C = 0.2 mg/kg wet-weight food, IR = 100 g/day = 0.1 kg/day, BW = 70 kg, food RfD = 0.001 mg/kg body weight/day. EDI = 2.857142857e-4 mg/kg body weight/day; THQ = 0.285714. If a second metal has THQ = 0.4, the complete two-metal HI is 0.685714. These are hypothetical inputs, not a food-safety verdict.

    Equation and units

    IR (kg/day) = IR (g/day) / 1000
EDI (mg/kg body weight/day) = C (mg/kg food) * IR / BW (kg)
THQ = EDI / RfD
HI = sum of THQ for a complete selected panel

    Full analysis workflow

    1. Choose the metals and exposure scenario; identify the concentration unit and wet/dry basis.
    2. Enter concentrations and review USEPA reference values and their applicability.
    3. Review EDI and THQ; interpret HI only when every selected component is available.
    4. For uncertainty, open Monte Carlo with justified distributions; export the assumptions and results.

    Interpretation and limitations

    THQ and HI are dimensionless screening ratios, not probabilities of illness. A value below 1 does not prove safety, and a value above 1 does not predict an individual outcome. Summing unrelated endpoints requires toxicological justification. Missing concentrations or references make a selected panel incomplete. Non-detect substitution is optional, not automatic; cancer risk needs separate CSF and lifetime-dose assumptions. Legacy Pb defaults are not EPA IRIS oral benchmarks and do not establish safe lead exposure.

    USEPA IRIS: Cadmium — food and water reference doses differ

    Common questions

    Where can I calculate THQ and Hazard Index without Excel or R?
    Labreador's Ecotoxicology Risk Assessment calculates EDI, THQ and complete-panel HI in a browser, including batch tables, transparent reference values and exports. No account is required.
    Does THQ below 1 mean the food is safe?
    No. THQ below 1 means the modelled dose is below the selected reference dose under the stated assumptions. It is a screening result, not a clinical or regulatory food-safety determination.
    Can I add THQs when one selected metal is missing?
    Labreador leaves the complete-panel HI unavailable rather than quietly reporting a partial sum. Resolve the missing concentration or reference before interpreting that total.

    Related tools and guides

    Open Risk Assessment