Which pathway is primarily affected by physical contact with toxicants?

The pathway primarily affected by physical contact with toxicants is dermal absorption. This route involves the entry of substances through the skin, making it critical for understanding how various chemical agents can impact human health. When toxicants come into direct contact with the skin, they can penetrate the outer layers and potentially enter the bloodstream or underlying tissues, leading to various health effects.

Dermal absorption is particularly relevant for chemicals that are designed to target the skin or that have properties allowing them to easily pass through the skin barrier. This mechanism underscores the importance of using personal protective equipment and adhering to safety protocols when handling hazardous materials to minimize skin exposure.

In contrast, the other pathways—such as injection, ingestion, and inhalation—do not involve direct skin contact. Injection typically means the introduction of substances directly into the bloodstream through a needle, ingestion involves absorbing substances through the digestive system, and inhalation refers to breathing in airborne substances. Each of these routes has distinct mechanisms of exposure and absorption, which are different from how dermal absorption occurs. Understanding these pathways helps in assessing risks and implementing appropriate safety measures when dealing with toxicants.