An evaluation of soil sampling for 137Cs using various field-sampling volumes

Area of Science:

• Environmental science
• Radiochemistry
• Geospatial analysis

Background:

• Cesium-137 (137Cs) is a significant radionuclide contaminant.
• Accurate environmental monitoring requires optimized sampling techniques.

Purpose of the Study:

• To evaluate and optimize field sampling strategies for 137Cs in sediments and soils.
• To determine the impact of sampling volume and replication on data variability and cost.

Main Methods:

• Sampling of sediments and soils at Los Alamos National Laboratory and Trinity site using various volumes (25-12,500 cm3).
• Statistical analysis of spatial, aliquoting, and counting variance components.
• Cost-benefit analysis of sampling strategies.

Main Results:

• Coefficients of variation for 137Cs inventory estimates ranged from 0.063-0.14 (Mortandad Canyon) and 0.38-0.57 (Trinity).
• Spatial variance was typically larger than aliquoting or counting variance.
• Optimization indicated counting 2-4 aliquots per sample is sufficient, reducing labor costs.

Conclusions:

• Sampling volume significantly impacts spatial variance, with larger volumes reducing it.
• Optimized sampling protocols can substantially decrease costs while maintaining data quality for 137Cs surveys.