A global company selling consumer products.


Health Criteria Values (HCVs) are expressed in different ways, using the terminology specific to the authority that is recommending them. Oral values represent a regular ingested dose that is expected to be without appreciable risk to the consumer over a lifetime. These can be expressed in the form of an ADI (Acceptable Daily Intake), a TDI (Tolerable Daily Intake) or TWI (Tolerable Weekly Intake), an RfD (Reference Dose), a cPAD (chronic Population-Adjusted Dose, calculated from an RfD and adjusted to take account of vulnerable subgroups of the population, such as children or women of childbearing age), an MRL (Maximum Residue Level) or a MADL (Maximum Allowable Dose Level). Some of these, such as MRLs and RfDs, are specific to non-cancerous long-term health effects. Inhalation values represent an atmospheric concentration that is expected to be without appreciable risk to humans over a lifetime (24 hours/day for 70 years) or a “working lifetime” (8 hours/day, 5 days/week, for 40 years). The former can be expressed as an RfC (Reference Concentration), a WHO air quality guideline, or a long-term population inhalation DNEL (Derived No-Effect Level). The latter include a TLV (Threshold Limit Value), a PEL (Permissible Exposure Limit with a legal obligation to comply), an REL (Recommended Exposure Limit), a WEEL (Workplace Environmental Exposure Level), an OEL/OES (Occupational Exposure Limit/Standard), an IOELV (Indicative Occupational Exposure Limit Value), a MAK (a German Maximum Workplace Concentration), or a long-term worker inhalation DNEL. Some of these, such as RfCs, are specific to non-cancerous long-term health effects.

Project goals

To identify and tabulate existing chronic oral HCVs for nearly 200 crop protection agents, and chronic oral and inhalation HCVs for around 250 chemically-defined flavouring agents.

Approach and outcome

Bibra toxicologists are very familiar with HCVs, and with the relevant national and international bodies that derive them. We used bibra’s chemically-indexed and fully searchable toxicity database, TRACE, to quickly and accurately identify source documents for the most up-to-date oral HCVs. Our confidence in TRACE’s ability to identify all of the relevant information meant that it was not necessary to widen the scope of our searches to include additional databases and/or search engines. For inhalation values, our in-house knowledge of the best two individual sources for the required information meant that we could rapidly retrieve all relevant values. The TRACE database and professional expertise of the bibra scientists maximised the efficiency and speed with which the project could be undertaken.

Bibra project team

Richard young 2023

Richard Young

Managing Director and Principal Toxicologist

RSB/BTS European Registered Toxicologist
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