Pesticide volatilization in biobed systems’ potential substrates. A viable simple laboratory experiment to determine pesticide losses to the environment.

• DOI: https://doi.org/10.22533/at.ed.9734124020110

• Palavras-chave: -

• Keywords: biobeds; organic substrates; pesticide volatilization; physicochemical parameters

• Abstract: -Pesticides in the environment represent a concern worldwide. Agriculture is the primary activity related to pesticide use and the main source of these compounds in the environment. To control and minimize pesticide use is a goal. The biobed systems are simple and proven systems retaining pesticides in agricultural plots, avoiding soil and water pollution. The biomixture is considered one of the most important aspects in these systems. The correct substrate selection guarantees the efficiency of the biobeds. Volatilization, runoff, and microbial activity are mechanisms that govern pesticide dissipation in biobeds. This research was developed to know the losses of pesticides in biobed systems due to volatilization. Five potential organic substrates (agricultural soil, sisal, corn stover, compost, and seaweed) were used in the biomixture. 2,4-D, atrazine, carbofuran, diazinon, and glyphosate, frequently used in Yucatan, México´s crops were selected and studied for 72 hours to different sampling times at microcosms level. A simple system was designed to catch the volatile pesticide. After 72 h, the highest values reported for volatile fraction were observed. Diazinon was the most volatile (~43% in soil), and glyphosate was the least (~43% in soil). Atrazine, considered as no volatile, was volatilized over 20% of the initial concentration in soil.  The exposure time and pesticide type on the volatile fraction of pesticide were statistically significant (P<0.05). Substrate type was significant on pesticide volatilization (P<0.05). Pesticide type was the most significant factor in pesticide volatilization; the pH, lignin content, and the final moisture in the substrate (% SM) were physicochemical characteristics of substrates that affected the pesticide volatilization. The results show that selecting the appropriate substrates that allow less pesticide volatilization guarantees that greater dissipation is carried out by degradation processes, taking into account that one of the main functions of biobeds is the confinement of agricultural effluents.