QSARs for aromatic hydrocarbons at several trophic levels

Area of Science:

• Environmental Toxicology
• Ecotoxicology
• Quantitative Structure-Activity Relationships (QSAR)

Background:

• Aromatic hydrocarbons are common environmental pollutants.
• Understanding their toxicity across different aquatic organisms is crucial for ecological risk assessment.

Purpose of the Study:

• To establish quantitative structure-activity relationships (QSARs) for the acute toxicity of aromatic hydrocarbons.
• To investigate interspecies variations in toxicity responses among different trophic levels.

Main Methods:

• Assayed toxicity of benzene and its alkylated derivatives against algae, zooplankton, invertebrates, and fish.
• Calculated EC50/LC50 values and performed nonlinear regression with log Kow.
• Analyzed bioconcentration factors (BCF) and critical body residues.

Main Results:

• QSARs showed a positive correlation with increasing log Kow across all trophic levels.
• Toxicity differences between algae and animals, and invertebrates and vertebrates, were observed.
• Algae exhibited greater resistance than fish and invertebrates for compounds with log Kow < 3.

Conclusions:

• Aromatic hydrocarbon toxicity is primarily driven by narcosis, linked to lipophilicity.
• Differences in toxicity responses diminish for compounds with higher log Kow (> 3).
• Predicted critical body residues for narcosis suggest a consistent toxic mechanism across species.