Screening for low aquatic bioaccumulation (2): physico-chemical constraints

Area of Science:

• Environmental Chemistry
• Ecotoxicology
• Risk Assessment

Background:

• Assessing the bioconcentration potential of xenobiotics is crucial for environmental risk assessment.
• Existing methods for determining bioconcentration factors (BCF) can be resource-intensive.

Purpose of the Study:

• To develop and validate a predictive model for identifying chemicals with low bioconcentration potential.
• To establish a decision tree based on physico-chemical properties to de-prioritize chemicals for bioassays.

Main Methods:

• Utilized physico-chemical properties including lipophilicity (log K(OW)), solubility, volatility (log Henry constant), degradability, and ionization.
• Developed a five-parameter classification scheme and decision tree using 382 industrial chemicals.
• Validated the model with 49 pesticides and 83 bioaccumulative compounds.

Main Results:

• The model successfully identified chemicals with low bioconcentration potential (BCF < 2000), de-prioritizing over 50% of tested chemicals.
• External validation confirmed the model's accuracy.
• Defined the applicability domain, excluding specific chemical classes like polybrominated compounds and organometallics.

Conclusions:

• The developed tool provides a scientifically sound and efficient method for prioritizing chemicals in environmental risk assessments.
• The model can reduce the necessity for bioassays for chemicals with low bioconcentration concern, saving resources and time.
• This approach supports regulatory efforts in managing persistent, bioaccumulative, and toxic (PBT) substances.