Radiation warning for Upper Hunter water
8/8/24: Radiation Warning for Upper Hunter Water (Inside Local Government)
Testing of drinking water from the Merriwa water supply groundwater bores has shown radiation levels are above the Australian Drinking Water Guidelines (ADWG) screening values, Upper Hunter Shire Council has revealed.
A result above the screening values does not mean the drinking water is unsafe, but means that further investigation is required, the Council said in a statement.
“In accordance with the ADWG, Upper Hunter Shire Council is undertaking further investigations. As a precaution, Council has moved to using the groundwater bores with the lowest radioactivity while the investigation is taking place,” Council said.
“Radioactive materials occur naturally in the environment and everyone is exposed to low levels of radiation. Some minerals that emit radiation can be present in drinking water and typically contribute a small amount to overall exposure to naturally occurring radiation. Naturally occurring radiation is more likely to be found in bore water. The radiation comes from naturally occuring sources including underground rock material that is in contact with the water.”
The Council is working with NSW Health and the Department of Climate Change, Energy, the Environment and water on the issue. Further investigation is underway to assure the ongoing safety of the Merriwa drinking water supply, the Council said.
“The community will be informed of all developments as further information becomes available,” it said.
“… A radionuclide is an unstable form of an atom that changes to form a more stable atom, emitting particles called radiation. In Merriwa’s case, it involves Alpha and Beta particles, which are from naturally occurring sources. NSW Health advises that the level of radiation is unlikely to pose a health risk NSW Health have assessed the maximum possible dose based on the current screen level results to be approximately 2mSv/year (milliSievert is a unit of radiation dose). The dose of radiation will be accurately calculated when the radionuclides in the water have been measured. Standard medical diagnostic equipment such as CT scans can deliver a dose as high as 10mSv.” https://www.upperhunter.nsw.gov.au/Residents/Water-and-Sewage/Merriwa-Water-Supply
“7.5.3 AVERAGE DOSE OF RADIATION
The dose of radiation received varies significantly between individuals and communities, and depends on locality, lifestyle, diet and type of dwelling. The global average for the individual dose of radiation from natural sources has been estimated to be 2.4 mSv/year (UNSCEAR 2000). Australian data suggest that the average annual dose in this country may be slightly lower, at approximately 2 mSv/year. Of this annual dose, less than 10 per cent comes from ingestion of food and drinking water containing radionuclides
from the natural uranium and thorium series (Webb et al. 1999)….
There are no specific reference levels set for specific alpha or beta emitting radionuclides. Specific alpha or beta emitting radionuclides should be determined if the gross alpha screening value in drinking water exceeds 0.5 Bq/L, or if the gross beta screening value (with the contribution of potassium-40 subtracted) exceeds 0.5 Bq/L, or if there is a specific reason
to analyse for individual radionuclides.” Australian Drinking Water Guidelines