In Silico Acute Aquatic Hazard Assessment and Prioritization Using a Grouped Target Site Model: A Case Study of...

Area of Science:

• Environmental Toxicology
• Computational Chemistry
• Risk Assessment

Background:

• Hydraulic fracturing (HF) utilizes diverse chemicals, complicating environmental risk assessment.
• Accurate estimation of aquatic hazard concentrations for these substances is crucial.

Purpose of the Study:

• To develop a transparent and reproducible method for estimating acute aquatic hazard concentrations (HC5s) for HF chemicals.
• To validate the developed model against existing toxicity data.

Main Methods:

• A simplified, grouped target site model (gTSM) was created using a database of 1696 compounds with known modes of action.
• 11 modes of action were statistically reduced to three hazard groups.
• The gTSM was trained and validated on an 80:20 split of the database, predicting toxicity via partition coefficients and hazard group concentrations.

Main Results:

• The gTSM achieved comparable performance to the original TSM with 40% fewer parameters.
• Model predictions were deemed reliable for prioritizing Permian Basin HF substances.
• The gTSM successfully predicted hazard groups, toxicity, and HC5s for 186 organic compounds, validated against measured data.

Conclusions:

• The gTSM is an efficient and cost-effective computational tool for rapid aquatic hazard assessment of diverse organic chemicals.
• This approach supports informed risk evaluation for chemicals used in hydraulic fracturing.
• The study demonstrates the utility of the gTSM in environmental risk management for the oil and gas industry.