Derivation of no-effect and reference-level sediment quality values for application at Saskatchewan uranium...

Area of Science:

• Environmental Science
• Ecotoxicology
• Aquatic Ecology

Background:

• Traditional sediment quality value (SQV) derivation often links metal concentrations to adverse benthic invertebrate effects.
• Existing methods may not fully account for local community tolerance or chemical interactions.

Purpose of the Study:

• Propose and validate a novel no-effect (NE) approach for deriving SQVs.
• Develop alternative regional SQVs for uranium operations in northern Saskatchewan.

Main Methods:

• The NE approach utilizes metal concentrations from reference and lightly contaminated sites with unaffected benthic communities.
• It incorporates benthic invertebrate tolerance and potential chemical interactions.
• Three sets of NE values were derived using different community effects criteria (abundance, richness, evenness, Bray-Curtis index).

Main Results:

• NE values varied based on the effects criteria used; NE values using abundance, richness, and evenness were generally higher than those using all four metrics.
• SQVs for Cr, Cu, Pb, and V remained unchanged, indicating minimal uranium operation influence.
• Gradients in As, Mo, Ni, Se, and U concentrations allowed for the definition of tolerable exposure levels.

Conclusions:

• The NE approach offers a robust methodology for deriving scientifically defensible SQVs.
• This study provides a range of new, alternative metal SQVs suitable for uranium operations in northern Saskatchewan.
• The findings contribute to improved environmental management and risk assessment in mining regions.