" Low Observed Effect Concentration " or concentration with a very weak observable effect. It is about the lowest concentration for which the effect is different from that of controls. It is the first concentration tested after the NOEC.
lowest observed effects concentration
(Lowest-observed-effect-concentration): The lowest concentration of an effluent or toxicant that results in adverse effects on the test organisms (i.e., where the values for the observed endpoints are statistically different from the control) (EPA, 2000).
Lowest observed effect concentration. The smallest observed concentration of a substance in water that produces a toxic response in an animal. The LOEC is used as a measure of the chronic or long-term toxicity of a substance, usually to water dwelling animals.
Lowest Observable Effect Concentration. The lowest concentration of a chemical at which a statistically significant, adverse effect is measurable on a test organism compared with controls. See NOEC.
The lowest toxicant concentration of an effluent or a toxicant in a chronic bioassay that caused an adverse effect statistically different from the control. Also referred to as the LOEL (Lowest Observed Effect Level).