Optimising sampling strategies for emergency response: Vegetation sampling.

Area of Science:

• Environmental Science
• Radiochemistry
• Ecology

Background:

• Chernobyl's legacy includes widespread radioactive contamination, particularly Cesium-137 (137Cs).
• Understanding radionuclide transfer from soil to plants is crucial for assessing ecological and human health risks.
• Previous studies highlighted variability in 137Cs concentrations, necessitating standardized sampling protocols.

Purpose of the Study:

• To analyze the variability of 137Cs activity concentrations in plants and aggregated transfer factors (Tag) from soil.
• To estimate uncertainties associated with Tag values across diverse landscapes in Chernobyl-affected regions.
• To develop an optimized method for radionuclide sampling in plants and assess measurement uncertainties.

Main Methods:

• Collected 25-49 paired plant and soil samples per site (1-10m grid increment) across agricultural and natural lands.
• Analyzed 137Cs activity concentrations in plants and soil to determine lognormal distribution parameters and Tag values.
• Evaluated the influence of deposition gradients, soil contamination, fallout type, and vegetation on variability.

Main Results:

• No significant deposition gradients were observed; variability was primarily due to random factors and microheterogeneity.
• Mean standard deviation of 137Cs activity concentration logarithms and Tag values were consistent across sites.
• Estimated average standard deviation for 137Cs activity concentration logarithms in plants and Tag values were 0.4 ± 0.1 and 0.5 ± 0.1, respectively.

Conclusions:

• 137Cs variability in plants and soil-to-plant transfer factors are largely independent of mean soil contamination, fallout type, and vegetation.
• Proposed a new method for optimizing sample numbers and estimating uncertainties for composite samples.
• Provided recommendations for effective plant sampling strategies for radionuclide assessment.