Chemical Structural Features Affecting the Soil Sorption of Sulfonylurea Herbicides

ABSTRACT

The contamination of groundwater by herbicides depends on their mobility in soil, which is related to the organic carbon to water partition coefficient, K_OC. Because the log K_OC values of widely used sulfonylurea herbicides do not correlate with easily accessible log P estimations, multivariate image analysis (MIA) descriptors were employed to build structure-property models to classify these compounds according to their soil sorption capability. In addition, a deeper analysis based on MIA contour maps of PLS regression coefficients and variable importance in projection scores was performed to obtain insight into the chemical features responsible for the log K_OC behavior. A multiple linear regression model obtained from selected descriptors demonstrated high predictability (r² = 0.95, q² = 0.84, and r²_pred = 0.71) and also provided chemical insight into the log K_OC values. It has been found that triazine rather than pyrimidine derivatives are less prone to leach out, but substituents attached to the sulfonyl group play an important role in modulating the log K_OC values. Consequently, useful guidance for environmental risk assessment is provided for the development of new sulfonylurea herbicides.

KEYWORDS:

• Structure-property
• log K_OC
• sulfonylureas
• leaching
• multivariate image analysis

Acknowledgments

The authors are thankful to Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES, funding code 001), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, grant number 306830/2021-3), and Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) for financial support of this research.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico [306830/2021-3]; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior [001]; Fundação de Amparo à Pesquisa do Estado de Minas Gerais .