Sublétal

Sublétal is a term used in toxicology and ecotoxicology to describe exposures or effects that do not cause immediate death but can impair biological function. A sublethal dose is typically defined as an exposure below the lethal threshold—often below the LD50 or LC50 for a given species—and may produce physiological, behavioral, or reproductive changes that influence survival and fitness.

Sublethal effects include slowed growth, reduced feeding, altered locomotion, impaired reproduction, changes in immune function, and altered behavior such as navigation or predator avoidance. In insects, pesticides may reduce foraging efficiency or brood viability; in aquatic organisms, pollutants can disrupt osmoregulation or hormone signaling. Because effects are often species-specific and context-dependent, they can be challenging to predict and may accumulate across life stages or generations.

Assessment often relies on endpoints like NOAEL (no observed adverse effect level) and LOAEL (lowest observed adverse effect level) from chronic exposure studies, rather than mortality data alone. Sublethal endpoints feed into risk assessment and regulatory decisions about safe exposure limits, labeling, and mitigation strategies. The concept highlights that non-fatal exposures can have substantial ecological and health consequences, affecting population dynamics and ecosystem services even when mortality is not observed.

Usage notes: In English, the term is sublethal; in some languages, including French, sublimatement may appear as sublimétal or sublimétal, but sublimétal is more common in toxicology literature. The core idea remains that non-lethal exposures can still produce meaningful adverse effects.