Wow, that's an interesting rabbit hole: https://en.wikipedia.org/wiki/Heavy_metals https://en.wikipedia.org/wiki/Heavy_metals. > Even in applications other tha

Wow, that's an interesting rabbit hole: https://en.wikipedia.org/wiki/Heavy_metals https://en.wikipedia.org/wiki/Heavy_metals. > Even in applications other than toxicity, no widely agreed criterion-based definition of a heavy metal exists. Reviews have recommended that it not be used. Different meanings may be attached to the term, depending on the context.