Appraising factors governing sorption and dissipation of the monoterpene carvone in agricultural soils

Abstract

The use of monoterpenes as agrochemicals has been proposed, but the behavior of this family of compounds once they reach the soil environment has not been completely examined. In this work, we investigated the sorption of the two optical isomers of the monoterpene carvone, R-carvone and S-carvone, on different soils and model sorbents, as well as their dissipation in selected soils. Sorption was a non-enantioselective process; from racemic initial solutions, R-carvone was sorbed to the same extent as S-carvone. Correlations with soil properties indicated that organic matter was the most important component determining the sorption of carvone on the soils. Accordingly, higher sorption of carvone enantiomers was measured on organic model sorbent (humic acid, Kd= 28 L kg-1) compared to mineral model sorbents (kaolinite, illite, montmorillonite, ferrihydrite, Kd < 6.3 L kg-1). Desorption from the soils was hysteretic, most likely because of the rapid degradation of the enantiomers in the soils. Dissipation of carvone in soils was microbial mediated and enantioselective, with S-carvone being degraded faster than R-carvone. The individual enantiomer dissipation rates and enantioselectivity depended on soil characteristics, such as pH. The findings of this study constitute a base for the understanding of the fate of monoterpenes in soils and for further investigations on their applicability as environmentally friendly agrochemicals.

S-Carvone Formulation Based on Granules of Organoclay to Modulate Its Losses and Phytotoxicity in Soil

“…A similar behavior had previously been described for the herbicide diuron supported on powder of the organoclay SA-HDTMA [42]. Interestingly, the half-lives obtained in this work for S-carvone contrasted with those previously found by Gámiz et al [8,21] for racemic carvone in similar Mediterranean soils, where much shorter half-life values between 0.7 and 0.8 days were obtained. It is important to note that, in this work, we used a different methodology and application rate in the dissipation experiment compared to those used in Gámiz et al [8,21].…”

“…Interestingly, the half-lives obtained in this work for S-carvone contrasted with those previously found by Gámiz et al [8,21] for racemic carvone in similar Mediterranean soils, where much shorter half-life values between 0.7 and 0.8 days were obtained. It is important to note that, in this work, we used a different methodology and application rate in the dissipation experiment compared to those used in Gámiz et al [8,21]. In particular, the dose of 100 mg/kg of S-carvone used here was greater than that of 2 mg/kg of racemic carvone used in Gámiz et al [8,21].…”

“…The formulation was allowed to air-dry for 24 h. In triplicate, 15 mg aliquots of the sample were extracted with 10 mL of methanol and analyzed by high-performance liquid chromatography (HPLC) to confirm the content in S-carvone of the formulation. Recoveries were >90%, as determined in [21]. The amount of S-carvone in the formulated granules was 3.0 ± 0.1%.…”

“…They can be transported by leaching to deeper soil layers or groundwater, volatilized, or chemically and/or biologically degraded [8,20]. Thus, the effect of different field conditions, such as UV radiation, humidity, pH, and inherent soil characteristics, on their stability needs to be solved [21,22] since they can be easily deteriorated by oxygen, light, moisture, heat, and microorganisms [23], leading to a reduction in bioavailability and bioactivity [9]. For instance, Karamanoli et al [16] studied the decomposition of essential oils in soils and established monoterpene biodegradation profiles with time.…”

Fotodegradação Catalítica Do Herbicida Hexazinona Utilizando O Tio2 Em Argissolo E Latossolo

“…A presença de matéria orgânica aumenta a capacidade tamponante e a CTC (Capacidade de troca catiônica) do solo. Diversos trabalhos já demonstraram o papel da matéria orgânica na adsorção de pesticidas orgânicos (BONFLEUR et al, 2015;GÁMIZ et al, 2018). Segundo Oliveira et al, (2011) a baixa CCT dos minerais de argila dos solos tropicais, a matéria orgânica, mesmo quando presente em pequenas proporções apresenta grande efeito sobre as propriedades físicoquímicas dos solos.…”