A review of radiation doses and associated parameters in western australian mining operations (2018-20)

In the 2019-20 reporting period, nineteen mining operations in Western Australia were identified as having workers who were likely to be exposed to ionising radiation stemming from naturally occurring radioactive materials (NORMs), seventeen of which, known hereinafter as Reporting Entities (REs), were required to submit an annual report of the dose estimates of their workforce to the mining regulatory authority. In 2018 the International Commission for Radiological Protection published the revision of the Dose Coefficients (DCs) for occupational intakes of radionuclides of the uranium-238 and thorium-232 decay series, in ICRP-137 and ICRP-141. The 2019-20 annual reports are the first to apply the revised DCs to estimate worker doses. The mean effective dose (ED) reported by the 17 REs increased by 32.4% to 0.94 mSv in 2019-20 from 0.71 mSv reported in 2018-19, indicating that the mean ED is approaching the 1 mSv annual dose estimate at which regulatory intervention should be considered. The mean committed effective dose (CED) from inhalation of dusts containing long-lived alpha-emitting (LLα) nuclides has increased by 35% from 0.40 mSv in 2018-19 to 0.54 mSv in 2019-20. The maximum CED from LLα increased by 16.3% from 3.20 mSv in 2018-19 to 3.72 mSv in 2019-20. The authors consider that, in the absence of other explanations provided by the REs, the increase is largely attributable to the revised DC’s published in ICRP-137 and ICRP-141, but highlight that there are significant variations between REs that make a generalised conclusion problematic. The maximum reported ED in 2019-20 was 6.0 mSv, an increase of 36.4% from 2018-19 (4.4 mSv). The 2019-20 reporting period is the first time in a decade in which mine worker EDs have been elevated to the point that EDs have exceeded 5 mSv, a level at which personal monitoring and additional institutional controls are required.

Decreasing hydrothermalism at Pamukkale- Hierapolis (Anatolia) since the 7th century

<p>The dating of travertine deposition and groundwater / hydrothermal seepages in relation to late Holocene climatic changes can be achieved using short-lived isotopes of the <sup>238</sup>U decay series, as illustrated by the present study of the Pamukkale travertine system, at the northern edge of the Denizli and Baklan graben merging area (see Özkul et al., 2013; https://doi.org/10.1016/j.sedgeo.2013.05.018. The strongly lithified self-built channels and modern pools where analysed for their <sup>238</sup>U, <sup>234</sup>U, <sup>230</sup>Th, <sup>226</sup>Ra, <sup>210</sup>Pb and <sup>210</sup>Po contents, whereas <sup>238</sup>U, <sup>234</sup>U and <sup>226</sup>Ra were measured in modern hydrothermal waters. When corrected for detrital contamination, <sup>230</sup>Th-ages of travertine samples range from 1215±80 years, in the oldest self-built hydrothermal channels, to the Present (modern pool carbonate deposits) thus pointing to the inception of the existing huge travertine depositional systems during the very late Holocene, probably following the major Laodikeia earthquate of the early 7<sup>th</sup> century (cf. Kumsar et al., 2016; DOI 10.1007/s10064-015-0791-0). So far, the available data suggest three major growth phases of the travertine system: an early phase (7<sup>th</sup> to 8<sup>th</sup> centuries CE), an intermediate phase (~ 14<sup>th</sup> century CE) and a modern one, less than one century old. A more detailed survey of the travertine system would be needed to strengthen these age clusters, however, worth of mention is the fact they they broadly fit with the timing of humid episodes as reconstructed from a southern Turkey paleolake study (Jones et al., 2006; doi: 10.1130/G22407.1). Despite nearly identical <sup>234</sup>U/<sup>238</sup>U activities in modern waters and travertines (1.132±0.006), the latter show decreasing <sup>226</sup>Ra concentrations through time, from ~ 0.2 dpm/g in the oldest shelf-built channels to ~ 0.07 dpm/g in present day pool carbonates, thus pointing to a significant decrease in the hydrothermal activity since the inception of the travertine complex, and raising concerns about the response of the Pamukkale hydrothermal system to the present climatic trend. Indeed, the predicted decrease in precipitation of up to 30% in the forthcoming decades (Lelieveld et al., 2012; DOI 10.1007/s10584-012-0418-4) is likely to result in a lesser meteoritic water recharge of the aquifer system feeding the springs (Dilsiz, 2006; DOI 10.1007/s10040-005-0001-4).</p>

Environmental study of natural radioactivity regime of the Ikaria island and the radiological impact

This is a preliminary study on the natural radioactivity of the spas in the Icaria island and the consequent impact to the public health. In order to carry out this research : a) Car-borne radiometry has been applied in the areas around the spas as well as in some reference areas in the island b) The activity concentrations of the natural radionuclides of the 238U-226Ra and 232Th decay series, as well as 40K, in spa water, soil, sediment, surface sea water and marine flora samples in the areas of the spas were measured, from the results derived one notes that elevated concentrations of the environmental abiotic materials are presented, which are reflected to the concentrations observed in marine flora. Consequently, higher population doses in comparison with other Greek regions are resulted.

Gamma spectroscopy studies of the underwater hydrothermal vent field of the Methana Peninsula

A preliminary study of natural radioactivity was conducted on the thermal spas in Methana Peninsula. To carry out this research, a collection of 17 water samples were taken from thermal springs around and underwater of the volcanogenic Peninsula at depths ranging 0–5 m. The Methana peninsula belongs to the Hellenic Volcanic Arc and is characterized by hydrothermal vent activity. A NaI(Tl) scintillator (AMESOS) was used to carry out gamma–ray counting of the samples to deduce the activity concentrations of the natural radionuclides of the 238U and 232Th decay series, as well as 40K in spa waters. Results are expected to provide information on the geological setting of the Methana peninsula. The impact of naturally occurring radioisotopes to human health has also been assessed in terms of the radiation dose risk corresponding to the measured activities.