What is the term for a substance that is poisonous to living organisms?

The term "toxic" specifically refers to substances that can cause harm to organisms through chemical interactions. This encompasses a wide range of effects on biological systems, such as cellular damage, impairment of physiological functions, or even death, depending on the dose and exposure. In the context of wastewater treatment, understanding toxicity is crucial, as it helps in identifying compounds that could negatively affect microbial populations pivotal to the treatment processes.

While "hazardous" could also be relevant, as it describes any substance that poses a risk to health or safety, it is a broader category that includes toxic substances among other risks. "Corrosive" refers to materials that can damage living tissue and materials through chemical reactions typically involving acids or bases, and "inert" describes substances that do not react under certain conditions and are generally considered to be safe or non-poisonous. Thus, the most precise term for a substance that is particularly harmful to living organisms is "toxic."