Abstract
We recently discovered that transformation of the neonicotinoid insecticidal pharmacophore alters sorption propensity to activated carbon, with products adsorbing less than parent compounds. To assess the environmental fate of novel transformation products that lack commercially available standards, researchers must rely on predictive approaches. In this study, we combined computationally derived quantitative structure–activity relationship (QSAR) parameters for neonicotinoids and neonicotinoid transformation products with experimentally determined Freundlich partition constants (log KF for sorption to carbon nanotubes [CNTs] and granular activated carbon [GAC]) to model neonicotinoid and transformation product sorption. QSAR models based on neonicotinoid sorption to functionalized/nonfunctionalized CNTs (used to generalize/simplify neonicotinoid-GAC interactions) were iteratively generated to obtain a multiple linear regression that could accurately predict neonicotinoid sorption to CNTs using internal and external validation (within 0.5 log units of the experimentally determined value). The log KF,CNT values were subsequently related to log KF,GAC where neonicotinoid sorption to GAC was predicted within 0.3 log-units of experimentally determined values. We applied our neonicotinoid-specific model to predict log KF,GAC for a suite of novel neonicotinoid transformation products (i.e., formed via hydrolysis, biotransformation, and chlorination) that do not have commercially available standards. We present this modeling approach as an innovative yet relatively simple technique to predict fate of highly specialized/unique polar emerging contaminants and/or transformation products that cannot be accurately predicted via traditional methods (e.g., pp-LFER), and highlights molecular properties that drive interactions of emerging contaminants.
Highlights
Neonicotinoids are among the most widely used insecticides in the world with applications in agriculture, forestry, home pest control, and pet flea and tick preventatives.[1−5] Due to their widespread use and hydrophilic nature,[6] neonicotinoids have become ubiquitous in natural and engineered systems throughout the U.S with detections between
Experiments with functionalized and nonfunctionalized carbon nanotubes indicate that the pharmacophore is a significant driver in neonicotinoid sorption,[47] similar to previous observations in soils.[37−39] This phenomenon is of particular concern because the neonicotinoid pharmacophore can be readily transformed in the environment both biotically[20−24] and abiotically
We recently reported[47] that when the neonicotinoid nitroimine pharmacophore is transformed to an imine/amine group, the sorption propensity of the products to carbon nanotubes (CNTs) and GAC significantly decreases, which is thought to be driven by alterations to the electrostatic and/or hydrogen bonding interactions that occur between the neonicotinoid pharmacophore and the carbon surface
Summary
Neonicotinoids are among the most widely used insecticides in the world with applications in agriculture, forestry, home pest control, and pet flea and tick preventatives.[1−5] Due to their widespread use and hydrophilic nature (log Kow −0.64 to 1.26),[6] neonicotinoids have become ubiquitous in natural (ground and surface waters) and engineered systems (drinking water and wastewater treatment plants) throughout the U.S with detections between
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
