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SUMMARY:An Integrated Baseline Environmental Radioactivity Assessment Acro
 ss Various Exposure Pathways
DTSTART;VALUE=DATE-TIME:20260519T082000Z
DTEND;VALUE=DATE-TIME:20260519T084000Z
DTSTAMP;VALUE=DATE-TIME:20260624T055226Z
UID:indico-contribution-3830@indico.tlabs.ac.za
DESCRIPTION:Speakers: Thato Molokwe (Centre for Nuclear Safety and Securit
 y)\nMonitoring natural radionuclides in the environment is important for e
 stablishing baseline radioactivity levels that support the evaluation of p
 ublic exposure. The study presents baseline environmental radioactivity le
 vels measured in collected soil\, external gamma\, water and indoor radon 
 samples to assess resultant public doses through external\, inhalation and
  ingestion exposure pathways. \n\nThe soil media comprised six (6) beach s
 and samples\, seven (7) sediments\, and twenty-two (22) surface soils. Wat
 er samples included twelve (12) surface water\, five (5) seawater\, and si
 xteen (16) groundwater samples\, which were analysed for natural radionucl
 ides originating from the Uranium-238\, Uranium-235 and Thorium-232 decay 
 series. External gamma radiation measurements were conducted at fifty-thre
 e (53) locations\, and indoor radon concentrations were measured in fiftee
 n (15) dwellings. The water and soil samples were analysed using calibrate
 d gamma spectrometry and alpha spectrometry. External gamma radiation was 
 measured in situ using a calibrated portable gamma survey meter (RS-230) t
 o determine ambient dose rates. Passive solid-state nuclear track detector
 s were deployed in dwellings for a period of three (3) months to measure i
 ndoor radon (Radon-222) concentrations.\n \nThe radioactivity levels measu
 red in soil samples were found to be significantly lower than the reported
  worldwide average values of 420 Bq/kg for Potassium-40\, 32 Bq/kg for Rad
 ium-226\, and 45 Bq/kg for Thorium-232. The calculated radiological hazard
  indices\, including radium equivalent activity and external hazard index\
 , were also below internationally recommended safety limits. Similarly\, r
 adioactivity levels in water samples were below the World Health Organisat
 ion’s (WHO) recommended drinking water reference levels\, corresponding 
 to an annual committed effective dose of less than 0.1 mSv/year. The measu
 red external gamma dose in the study area due to natural background radiat
 ion was below the reference level of 1 mSv/year\, which is the public dose
  limit for planned exposure situations. Indoor radon concentrations were g
 enerally below the 100 Bq/m³ reference level recommended by the World Hea
 lth Organisation\, except for one measurement (117 Bq/m³)\, which was non
 etheless below the 300 Bq/m³ action level recommended by the Internationa
 l Atomic Energy Agency (IAEA). Further investigations indicated that the e
 levated level was unlikely to be attributed to underlying geology but may 
 instead be attributed to factors such as building characteristics or venti
 lation.\n\nThe results of this study provide integrated baseline data of e
 nvironmental radioactivity levels\, which are relevant for environmental m
 onitoring and assessment of public exposure. These findings support radiat
 ion protection and safety initiatives.\n\nhttps://indico.tlabs.ac.za/event
 /139/contributions/3830/
LOCATION:NRF-iThemba LABS\, Old Faure Road\, Cape Town Auditorium
URL:https://indico.tlabs.ac.za/event/139/contributions/3830/
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