What does the term "excretion" refer to in toxicokinetics?

In the context of toxicokinetics, "excretion" specifically refers to the process through which toxic substances are eliminated from the body. This is a critical aspect of understanding how the body manages and processes harmful substances. Excretion can occur through various routes, including urine, feces, breath, and sweat, serving as a vital mechanism to rid the body of toxins that could potentially cause harm.

The other choices do not accurately define excretion. Detection of toxic substances in the bloodstream pertains to the assessment or measurement of the presence of these substances, rather than their removal. The conversion of toxins into harmless substances describes biotransformation or metabolism, a different step in the process of handling toxins. Absorption through the skin relates to how toxins enter the body rather than how they leave it. Thus, the focus on the removal process in the correct answer aligns with the definition of excretion in toxicokinetics.