Pesticides and Transformation Products in Rapeseed-Rice Rotation Soils: Nontarget Analysis and Associations with...

Area of Science:

• Environmental Chemistry
• Soil Microbiology
• Agricultural Science

Background:

• Pesticide contamination in aquatic environments is a known issue.
• Impacts on soil nitrogen cycling functions are less understood.
• Agricultural soils accumulate pesticides and their transformation products (TPs).

Purpose of the Study:

• To identify residual pesticides and TPs in rapeseed-rice rotation soils.
• To investigate the association between pesticides/TPs and ammonia-oxidizing microorganisms (AOMs).
• To assess the differential susceptibility of AOMs to pesticides and TPs.

Main Methods:

• Target, suspect, and nontarget screening for pesticide and TP identification.
• Quantification of pesticide and TP concentrations in soil.
• Analysis of AOM abundance and community structure in relation to pesticide/TP levels.

Main Results:

• Numerous pesticides and TPs were identified, including novel compounds.
• TP concentrations were comparable to parent pesticides, with rhizosphere enrichment.
• Ammonia-oxidizing archaea and comammox Nitrospira were more sensitive to pesticides/TPs than bacteria.
• Some TPs exhibited higher toxicity to AOMs than parent pesticides, particularly in the rhizosphere.

Conclusions:

• Pesticide and TP contamination affects soil nitrogen-cycling microorganisms.
• TPs can pose significant risks to AOMs, potentially altering nitrogen cycling.
• Further research is needed on long-term impacts of pesticide-induced microbial shifts in agricultural soils.