Validation of a new sampler for radon gas measurements in surface water

Radon gas (Rn-222) in water poses health risks due to radiation exposure, yet it's also an important tracer for studying natural systems. Sampling procedures for Rn-222 analysis are very sensitive to potential losses of the gas to the atmosphere. It requires a well-defined and properly validated protocol to ensure accuracy and reliability. A novel sampler was developed to collect surface water from a distance (e.g. from bridges), addressing logistic challenges posed by topography. The sampler, manually operated, ensures precise depth-specific sampling throughout the water column. A three-stage validation process (technical performance test, uncertainty estimations and preliminary test) was followed to validate the protocol.•The comparison of the technical procedure for analysis and measurement through Liquid Scintillation Counting is statistically robust (one-way ANOVA p-value = 0.96).•For the protocol proposed for Rn-222 determination, the estimated sampling and measurement uncertainties (k = 2) are respectively 5% and 15%. These are compatible with the literature and the laboratory's precision.•Preliminary tests, with meaningful patterns identified and possibly related to the river's hydrodynamics, revealed a very reliable protocol, even in low Rn-222 concentrations.Therefore, the sampler has demonstrated a good analytical reproducibility and was considered validated for Rn-222 determination in surface waters.