Analysis of Cs-137 and Sr-90 in Wood and Wood Ash from Austria: Dose Assessment.
Presented by: Viktoria Herzner
Time: 3pm AEST (1pm AWST)
PRESENTER BIO
Viktoria Herzner is a Radiation Protection Expert at the Austrian Agency for Health and Food Safety (AGES) since October 2019. Ms Herzner has a Bachelor and Masters degree in Technical Physics, and is currently undertaking a Doctoral Program in Agriculture, University of Natural Resources and Life Sciences, Vienna, Austria. Her doctoral thesis is titled ‘Wood fuels and their combustion residues from the point of view of radiation protection with a focus on the activity concentrations of Cs-137 and Sr-90 as a result of the reactor accident at Chernobyl.’ Ms Herzner is also the Chair of the Young Scientists & Professionals within the Austrian Association for Radiation Protection. Fun fact: During the gap between her Bachelor’s and Master’s degrees, Ms Herzner spent five months travelling in Australia, working on farms and staying with different families. Now, Ms Herzner is looking forward to returning to Darwin, at the latest for the IRPA18 conference
ABSTRACT
The aim of this study was to evaluate the radiological risk to the public due to the use of wood ash as a fertilizer in gardens.
The Chernobyl fallout contaminated Europe with Cs-134, Cs-137, Sr-89 and Sr-90. Thirty years later Cs-137 and Sr-90 can still be detected in the vegetation and wild animals.
In a prior study (currently in the submission process for publication), measurements and comparisons of 69 distinct wood fuel samples and 27 wood ash samples were made against existing literature. The wood fuels analysed were logs, chips, briquettes and pellets. The measurements of Cs-137 activity concentration of the wood fuels ranged between (0.327 ± 0.077) and (8.36 ± 0.78) Bq kg-1, which indicated no necessity for special regulations on wood imported to Austria. The Cs-137 activity concentration in the wood ash samples ranged between (11.80 ± 0.87) and (867 ± 68) Bq kg-1 and the Sr-90 activity concentration ranged between (363 ± 53) and (1,200 ± 180) Bq kg-1.
In the previous study, the samples were taken from 26 private households, and these households were also asked about their disposal route for wood ash. Most members of the public in Austria (14 out of 26 private Austrian households) are using wood ash in their private gardens. A dose assessment for the use of wood ash as a fertilizer in private gardens was carried out in this study. Dose assessment is a crucial process in radiation protection that involves determining the amount of radiation to which a person or population has been exposed. The assessment of radiation dose will help to evaluate potential health risks better to ensure that radiation exposure remains within safe limits.
For a member of the public older than 17 years using the highest concentrations of Cs-137 and Sr-90 measured in the previous study the resulting calculated dose was (0,139±0,011) mSv per year. The main part of the dose arises from the ingestion of locally produced foods fertilized with pellet ash. In addition to radioactive substances, ash also contains concentrated non-flammable and potentially harmful minerals, salts, heavy metals and organic pollutants. It is not recommended to fertilise the garden or even a vegetable patch with wood pellet ash. In the following stage, it is planned to examine wood ash from industrial plants and determine whether this ash can be further used as a building material.
