Physical-chemical properties of pesticides: concepts, applications, and interactions with the environment

What are the molecular properties of agricultural chemicals, how do they function and why should they be studied? How do they affect the agroecosystem and how are they linked to application technologies? These questions arise due to the lack of information in the literature about this issue and form the basis of the current review. In general, a better understanding of the physical-chemical characteristics of agricultural chemicals makes it possible to improve their efficiency of application, consequently reducing losses and maintaining the integrity of the environment. These points underscore the importance of this subject, which has been deeply discussed in Europe. In Brazil, there are few studies that examine the physicochemical properties of pesticides at the molecular level and virtually none that examine their impact. Thus, the current study attempts to clarify the concepts, applications, and interactions of the physical-chemical properties of agricultural chemicals with the environment. The trade secrets associated with these molecules are essential to the agrochemical industry, which certainly restricts scientific publications on the topic. Nevertheless, these properties are linked to the products' mobility in the soil, disassociation in water, bioaccumulation, persistence, and durability in the environment and on the target. In summary, the more mobile and persistent a molecule is, the greater its potential for seepage and leaching and, consequently, the greater its potential for contaminating surface, subsurface, and ground water. This type of molecule becomes more environmentally aggressive if it bioaccumulates readily and degrades slowly. It should be noted that proper handling of agrochemicals depends not only on an understanding of their molecular properties, but also on their safe application. These concepts are essential for the successful promotion and sustainable use of these products in rural areas