Selenium-to-mercury ratios do not silently relax methylmercury controls

The controlling scientific record is the public Heavy Metal Index synthesis, supported by 3 named anchor sources and expressed for Methylmercury, Mercury.

ICS does not reproduce the source extraction here. Keeping the evidence on the independent index preserves source-level methods, units, species, basis, uncertainty, and review state. This note records only the institutional consequence of that evidence.

Retain the selenium-mercury ratio as a disclosed scientific debate and reject any automatic relaxation of a methylmercury requirement absent an explicit, externally governed rule.

This disposition may change taxonomy, analyte coverage, test basis, surveillance priority, disclosure, or claim language. It does not allow a market occurrence percentile or a dramatic single study to become an initial certification value.

The finding is published in two additional authority layers: the HMI evidence record and the HMTc certification interpretation. Distribution should prioritize toxicologists, seafood suppliers, regulators, attorneys while preserving those distinct roles in headlines, briefings, interviews, and social posts.