Behavior and fate of fungicide chlorothalonil in urban landscape soils and associated environmental concern

Abstract

This novel study investigated the behavior and fate of chlorothalonil in terms of kinetics, sorption‒desorption and leaching potential in urban landscape soils using batch experiments. The pseudo-second-order model well described the sorption kinetics of chlorothalonil in urban soils. Consequently, chlorothalonil was partitioned into heterogeneous surfaces of soil following the Freundlich isotherm model. According to PCA, soil organic matter (OM), silt, clay, and oxides of Al and Fe exhibited a significant positive correlation (P < 0.05) with chlorothalonil K_d (P < 0.05), while sand content and soil pH showed a negative correlation at P < 0.05. In soils, decreased sorption of chlorothalonil was also due to the presence of undecomposed or partly decomposed OM, whereas increased sorption could be attributed to the combined effect of OM with C = O and C–H groups, silt, clay, Al and Fe oxides and hydrophobicity of the fungicide. Also, HI, GUS, LIX and K_d of four among nine urban soils indicated that chlorothalonil has a great potential for leaching into the groundwater from the soil surface, posing an unintended threat to non-target biota and food safety. Therefore, utmost care must be taken while applying chlorothalonil in urban landscapes, particularly on impervious surfaces, to minimize the impact on the ecosystem.

Keywords:

• Urban landscape soils
• chlorothalonil
• sorption‒desorption
• leaching potential
• environmental health risk

Acknowledgments

MMI acknowledges the Australian Government for Research Training Program (RTP) scholarship, and Sher-e-Bangla Agricultural University, Bangladesh for granting study leave for PhD program.

Declaration of competing interest

There are no conflicts to declare.

Author contributions

Islam Md Meftaul: Investigation, Methodology, Data curation, Validation, Writing original draft. Kadiyala Venkateswarlu: Writing review and editing. Prasath Annamalai: Methodology. Aney Parven: Data curation, validation. Zahra Sobhani: Methodology. Mallavarapu Megharaj: Conceptualization, Supervision, Writing review and editing.

Additional information

Funding

This study is funded by Australian Government and University of Newcastle.