Which formulation of 2,4-D is known to be most toxic to fish?

The liquid ester formulation of 2,4-D is known to be the most toxic to fish due to its chemical composition and the way it interacts with aquatic environments. The ester form of 2,4-D has a structure that allows it to be more lipophilic, which means it can readily dissolve in oils and lipids. This characteristic can lead to higher bioaccumulation in fish tissues, resulting in increased toxicity. Additionally, esters can be more readily absorbed by aquatic organisms, leading to adverse effects such as impaired growth, reproductive issues, and even mortality.

In contrast, the other formulations mentioned, such as aqueous solutions, granular formulations, and water-dispersible powders, generally have lower toxicity levels. These formulations may dissolve more readily in water but do not have the same propensity for bioaccumulation in fish tissues. Understanding these differences is crucial for aquatic pesticide applicators to ensure they select the most appropriate formulation while minimizing the impact on non-target aquatic organisms.