What does a PECQ value of less than 1 indicate?

A PECQ value of less than 1 indicates that the concentration of a substance in the environment is lower than the level at which harmful effects on the ecosystem are expected. This suggests that the substance is unlikely to pose a risk of toxicity to ecological receptors. In other words, if the PECQ is below 1, it typically signifies that the substance is present at a concentration deemed safe, providing a level of assurance that it is unlikely to cause adverse effects. Understanding this concept is essential for risk assessment and environmental management, as it helps in determining the safety of various substances in different environmental settings.