New PEC definitions for river basins applicable to GIS-based environmental exposure assessment

Area of Science:

• Environmental Chemistry
• Hydrology
• Risk Assessment

Background:

• GREAT-ER (Geo-Referenced Regional Exposure Assessment Tool for European Rivers) facilitates aquatic chemical fate simulations.
• Digital maps of predicted concentrations require aggregation for regional exposure and risk assessment.

Purpose of the Study:

• To propose and test two spatially aggregated Predicted Environment Concentration (PEC) definitions for river catchments.
• To evaluate the suitability of PECinitial (unweighted) and PECcatchment (weighted) for representing aquatic exposure.

Main Methods:

• Utilized the GREAT-ER tool for aquatic chemical fate simulations in two pilot river basins (Calder and Went, UK).
• Developed and applied two novel aggregation methods: PECinitial and PECcatchment.
• Compared the results of the two PEC definitions to assess their representativeness.

Main Results:

• Simulations confirmed the theoretical basis for the proposed PEC definitions.
• The study demonstrated that weighting is necessary to resolve scale-dependencies in exposure assessment.
• PECcatchment, a weighted aggregation, proved more effective in addressing scale issues.

Conclusions:

• The proposed PEC definitions are valuable for regional aquatic exposure assessment using GREAT-ER.
• Weighted aggregation (PECcatchment) is crucial for accurate representation of exposure across different scales.
• Further application of these methods can improve environmental risk assessments in river basins.