Identification of Pesticide Transformation Products in Surface Water Using Suspect Screening Combined with National Monitoring Data

Pesticides are widespread
anthropogenic chemicals and well-known
environmental contaminants of concern. Much less is known about transformation
products (TPs) of pesticides and their presence in the environment.
We developed a novel suspect screening approach for not well-explored
pesticides (n = 16) and pesticide TPs (n = 242) by integrating knowledge from national monitoring with high-resolution
mass spectrometry data. Weekly time-integrated samples were collected
in two Swedish agricultural streams using the novel Time-Integrating,
MicroFlow, In-line Extraction (TIMFIE) sampler. The integration of
national monitoring data in the screening approach increased the number
of prioritized compounds approximately twofold (from 23 to 42). Ultimately,
11 pesticide TPs were confirmed by reference standards and 12 TPs
were considered tentatively identified with varying levels of confidence.
Semiquantification of the newly confirmed TPs indicated higher concentrations
than their corresponding parent pesticides in some cases, which highlights
concerns related to (unknown) pesticide TPs in the environment. Some
TPs were present in the environment without co-occurrence of their
corresponding parent compounds, indicating higher persistency or mobility
of the identified TPs. This study showcased the benefits of integrating
monitoring knowledge in this type of studies, with advantages for
suspect screening performance and the possibility to increase relevance
of future monitoring programs.