Sampling in freshwater environments: suspended particle traps and variability in the final data

Area of Science:

• Environmental Science
• Analytical Chemistry
• Ecosystem Monitoring

Background:

• Accurate measurement uncertainty is crucial for environmental monitoring and risk assessment.
• Previous methods for uncertainty estimation in environmental sampling have limitations.
• Cesium-137 ((137)Cs) and total carbon are key environmental indicators in aquatic ecosystems.

Purpose of the Study:

• To apply a practical method for estimating measurement uncertainty, including sampling and analysis components.
• To evaluate the uncertainty associated with (137)Cs activity concentration and total carbon content in freshwater suspended particles.
• To compare the contributions of spatial, sampling, and analysis variances to the total uncertainty.

Main Methods:

• Adapted Ramsey's method for soil investigations to estimate measurement uncertainty.
• Applied the methodology to suspended particle sampling in a freshwater ecosystem.
• Quantified uncertainty components for (137)Cs activity concentration and total carbon content.

Main Results:

• Relative expanded measurement uncertainties were 12.3% for (137)Cs and 4.5% for total carbon.
• For (137)Cs, measurement (sampling+analysis) variance was the major contributor to total variance.
• For total carbon, spatial variance was the dominant contributor to total variance.

Conclusions:

• The adapted method provides a practical approach for estimating measurement uncertainty in freshwater suspended particle analysis.
• Understanding the dominant sources of uncertainty is vital for optimizing sampling and analytical strategies.
• The method offers insights into the reliability of environmental data for (137)Cs and total carbon.