A Framework to Predict Uptake of Trace Organic Compounds by Plants

Area of Science:

• Environmental Chemistry
• Agricultural Science
• Toxicology

Background:

• Trace organic compounds (TOrCs) can enter food crops through agricultural applications of manure, biosolids, and recycled wastewater.
• Assessing the bioaccumulation potential of TOrCs in crops is crucial for food safety and risk evaluation.
• Mammalian and plant cell membranes share structural and functional similarities, suggesting similar principles of compound permeability.

Purpose of the Study:

• To develop a predictive framework for identifying TOrCs with high bioaccumulation potential in food crops.
• To adapt Lipinski's drug permeability rules for evaluating TOrC uptake and bioaccumulation in plants.
• To prioritize TOrCs for detailed risk assessment based on their likelihood of plant uptake.

Main Methods:

• Modified Lipinski's rule, focusing on four critical molecular properties: molecular weight (MW), lipophilicity (logP), hydrogen bond acceptors, and hydrogen bond donors.
• Developed the "Rule of 3" (logP < 3, MW < 300, H-bond donors < 3, H-bond acceptors < 6) for predicting high TOrC permeability.
• Validated the framework using published data on TOrC uptake and bioaccumulation in plants.

Main Results:

• The "Rule of 3" effectively predicted higher absorption and permeability of TOrCs in plants.
• TOrC uptake and bioaccumulation decreased in the order: Rule of 3 > Rule of 3 to 5 > Rule of 5.
• Compounds adhering to the "Rule of 3" demonstrated the greatest potential for plant uptake and bioaccumulation.

Conclusions:

• The developed "Rule of 3" framework provides a practical method for prioritizing TOrCs for risk assessment.
• TOrCs meeting the "Rule of 3" criteria warrant detailed investigation regarding dietary exposure risks.
• This approach aids in managing potential risks associated with TOrCs in agricultural systems.