Aquatic ecotoxicological indicators in life-cycle assessment.

Area of Science:

• Environmental Science
• Ecotoxicology
• Life-Cycle Assessment (LCA)

Background:

• Evaluating aquatic ecotoxicological effects in LCA is complex.
• Existing methods often rely on species-sensitivity distributions (SSDs) and struggle with chemical mixtures.
• A standardized, effective approach is needed for risk assessment.

Purpose of the Study:

• To compare available aquatic ecotoxicological effect factor options for LCA.
• To identify the best available practice for calculating these factors.
• To simplify risk assessment for chemicals in environmental exposure.

Main Methods:

• Comparison of effect factor approaches linked to species-sensitivity distributions (SSDs).
• Analysis of implications for chemical mixtures and model choices.
• Focus on risk-based factors expressed as delta effect/delta exposure.

Main Results:

• A single, risk-based effect factor (deltaPAF(ms)/deltaC = 0.5/HC50) is proposed as best practice for LCA.
• This factor accounts for background mixtures and uses the median hazardous concentration (HC50).
• Factors can be estimated readily for many chemicals, e.g., using the octanol-water partitioning coefficient for narcosis modes of action.

Conclusions:

• The proposed single effect factor represents the best available practice for aquatic ecotoxicological assessment in LCA.
• This approach simplifies calculations, requires less data, and is applicable to chemicals at low environmental concentrations.
• It provides a robust, risk-based foundation for environmental impact assessment.