Using public participation to sample trace metals in lake surface sediments: the OPAL Metals Survey

Area of Science:

• Environmental Chemistry
• Geochemistry
• Citizen Science

Background:

• Metals contamination in aquatic ecosystems poses risks to biota.
• Previous assessments often lacked broad spatial coverage.
• Public participation offers a novel approach to national environmental monitoring.

Purpose of the Study:

• To assess metals contamination in English ponds and lakes using citizen science.
• To validate the reliability of public-collected sediment samples for geochemical analysis.
• To understand factors influencing metal variability in littoral sediments.

Main Methods:

• A national survey invited the public to collect littoral sediment samples from standing water bodies.
• Geochemical analysis was performed on collected samples for metals (Hg, Ni, Cu, Zn, Pb).
• A calibration exercise at ten diverse water bodies validated the public sampling method.

Main Results:

• Metals concentrations (Hg, Ni, Cu, Zn, Pb) frequently exceeded aquatic health guidelines across England.
• Contamination was widespread, not limited to historically industrial areas.
• Littoral sediment metal variability was low in small lowland lakes but higher in larger, complex catchments.

Conclusions:

• Public participation in sediment sampling is a viable method for preliminary metals contamination assessment in small lakes and ponds.
• While valuable, citizen science requires complementary systematic sampling for comprehensive national assessments.
• Understanding local factors like organic content and geology is crucial for interpreting metal concentrations.