One well-known example is the pathway of lead toxicity. Lead is absorbed primarily through ingestion and inhalation and is distributed to bones, brain, and kidneys. It undergoes minimal metabolism, with excretion occurring slowly, mainly via urine. Accumulation in bones can cause chronic health issues. Another example is alcohol metabolism, where ethanol is oxidized to acetaldehyde by alcohol dehydrogenase, then further metabolized to acetate by aldehyde dehydrogenase, before being excreted.
