Scientific uncertainty

The Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT) has published its review of  variation and uncertainty in toxicology.  It will provide a valuable guide for the committee's future work characterising the hazards associated with exposure to chemicals from food and other sources.

The report discusses the current commonly-used method of setting health-based guidance values for chemicals on the basis of no-observable-effect levels (NOAEL).

It also sets out the value of sometimes using alternative approaches, such as using a benchmark dose level (BMDL), a margin of exposure (MOE) or a threshold of toxicological concern (TTC) to characterise hazards.

I find this discussion timely with regard to European proposals to include use of the BMDL and MOE in the risk assessment of some genotoxic carcinogens.

I'm reassured that the report concludes that the uncertainty factors frequently used in regulatory toxicology are adequate to ensure the safety of all consumers (including at–risk sub-groups such as the elderly, the young, the sick and pregnant women).

But the report also recognises that there may be occasions where the need for an additional safety factor should be considered on a case-by-case basis.

I was particularly interested to see the conclusion regarding the young, as this is relevant to the 'Why doesn’t the EFSA heed European policy on protecting children?' that was posted on my December 2006 blog.