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Assessment of Environmental Radioactivity and Health Hazard in Soil, Water, and Stone Samples in Siverek Town of Sanliurfa Province in Southeastern Turkey
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Available online at www.sciencedirect.com Procedia Computer Science 00 (2019) 000–000
www.elsevier.com/locate/procedia
ScienceDirect Procedia Computer Science 158 (2019) 125–134
3rd World Conference on Technology, Innovation and Entrepreneurship (WOCTINE) 3rd World Conference on Technology, Innovation and Entrepreneurship (WOCTINE) Assessment of Environmental Radioactivity and Health Hazard in Soil, Water, Stone Samples in Siverekand Town of Sanliurfa Assessment of and Environmental Radioactivity Health Hazard in Province in Southeastern Turkey Soil, Water, and Stone Samples in Siverek Town of Sanliurfa Province inCelik Southeastern Turkey , Ilker Can , Mehmet Kosal 1*
Abstract
1
Ilker Can Celik , Mehmet Kosal
1
1,* 1 Faculty of Arts and Sciences, Department of Physics, Harran University, 63300 Sanliurfa, Turkey
1
Faculty of Arts and Sciences, Department of Physics, Harran University, 63300 Sanliurfa, Turkey
Human life depends on water and soil where our food mostly needs to be grown. Let us not forget the nature and rocks that we Abstract are surrounded in terms of structural base. For that reason, it’s crucial to determine their radioactivity level not just to help mapping the Human country’s measurements, but to assess and protection. the International liferadiation dependsbackground on water and soil where our food mostlypeople’s needs tosafety be grown. Let us notEspecially, forget the nature and rocks Atomic that we Energy Agencyin(IAEA), United Nations Scientific Committee on the Effects oftheir Atomic Radiationlevel (UNSCEAR), Health are surrounded terms ofthe structural base. For that reason, it’s crucial to determine radioactivity not just to World help mapping Organization (WHO), or the International Commission Radiological Protection (ICRP) develop safetythe standards to protect the the country’s radiation background measurements, but toon assess people’s safety and protection. Especially, International Atomic health and to minimize people’s life before anything happens. specific study, (UNSCEAR), the most densely populated Energy Agency (IAEA),the the danger United for Nations Scientific Committee on the EffectsInofthis Atomic Radiation World Health county, called(WHO), Siverek,orinthe theInternational region of Sanliurfa municipality was selected. For the(ICRP) analysis of soil safety and rock, respectively 11 and Organization Commission on Radiological Protection develop standards to protect the 7health distinctive determine activity levelshappens. in HarranInUniversity laboratory. to water samples, only and tolocations minimizewere the considered danger for to people’s life the before anything this specific study, theAsmost densely populated two samples were proceeded detectof total alpha and beta activities Cekmece Research andand Education Centre (CNAEM) county, called Siverek, in thetoregion Sanliurfa municipality wasby selected. ForNuclear the analysis of soil rock, respectively 11 and by Turkish Atomic Energy (TAEK). 7 distinctive locations wereAgency considered to determine the activity levels in Harran University laboratory. As to water samples, only regard analysis tools, Ortec used Research to detect and anyEducation activity based naturally twoWith samples weretoproceeded to detect totalbrand alphaNaI(Tl) and betascintillation activities bydetector Cekmecewas Nuclear Centreon(CNAEM) occurring materials (NORM), such as 238U, 232Th, and 40K elements in soil and stone samples with the help of digibase by Turkishradioactive Atomic Energy Agency (TAEK). MCA system. activity investigation, low-level activity measurement system of LB770-PC withbased 10 channels, were With regardFor to water analysis tools,level Ortec brand NaI(Tl) scintillation detector was used to detect any activity on naturally used. occurring radioactive materials (NORM), such as 238U, 232Th, and 40K elements in soil and stone samples with the help of digibase As system. a result,For it’s water expected to find theinvestigation, levels of the low-level most encountered activity units;system such asofRadium equivalent indoorwere and MCA activity level activity measurement LB770-PC with 10dose, channels, outdoor used. external absorbed doses, internal and external hazard indices, indoor and outdoor annual effective doses, indoor and outdoor life-time cancer risksthe lower than that some organizations stated literature. As a excess result, it’s expected to find levels of the the values most encountered activity units; suchinastheir Radium equivalent dose, indoor and outdoor external absorbed doses, internal and external hazard indices, indoor and outdoor annual effective doses, indoor and outdoor excess life-time cancer risks lower than the values that some organizations stated in their literature. © 2019 The Author(s). Published by Elsevier B.V. © 2019 The Authors. Published by of Elsevier B.V. Peer-review under responsibility the scientific committee of the 3rd World Conference on Technology, Innovation and Peer-review under responsibility of the scientific committee of the 3rd World Conference on Technology, Innovation and © 2019 The Author(s). Published by Elsevier B.V. Entrepreneurship Entrepreneurship Peer-review under responsibility of the scientific committee of the 3rd World Conference on Technology, Innovation and Keywords: NaI(Tl) detector; Siverek; Sanliurfa; NORM; UNSCEAR; WHO; ICRP; IAEA; Activity units. Entrepreneurship * Corresponding author.detector; E-mail address: [email protected] Keywords: NaI(Tl) Siverek; Sanliurfa; NORM; UNSCEAR; WHO; ICRP; IAEA; Activity units. * Corresponding author. E-mail address: [email protected]
1877-0509 © 2019 The Author(s). Published by Elsevier B.V. Peer-review under responsibility of the scientific committee of the 3rd World Conference on Technology, Innovation and Entrepreneurship 1877-0509 © 2019 The Author(s). Published by Elsevier B.V. Peer-review under responsibility of the scientific committee of the 3rd World Conference on Technology, Innovation and Entrepreneurship
1877-0509 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the scientific committee of the 3rd World Conference on Technology, Innovation and Entrepreneurship 10.1016/j.procs.2019.09.035
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Ilker Can Celik et al. / Procedia Computer Science 158 (2019) 125–134 Ilker Can Celik / Procedia Computer Science 00 (2019) 000–000
1. Introduction Living organisms are exposed to radiation by naturally occurring radioactive materials or man-made radioactive products. In this study, our work was focused on the natural side of the cause. Therefore, investigation took place in soil, stone and water samples due to their vast amounts in our surroundings as human beings. These primordial radionuclides have long enough half-lives that they still exist since the beginning of the Earth. Moreover, it’s possible to calculate their activities from their daughter nuclei in their decay chains. Both shorter half-lives of these daughter nuclide and their radioactivity traces are detectable with current technology. That enables us to study them as a physicist. For that reason, it’s crucial to know at what level they have possibility to harm us through our lifespan. Careful investigations have been ongoing for many years to detect mainly the activity levels by means of either gamma-ray in 238U, 232Th, 40K or alpha and beta activities in natural formations. Siverek town of Sanliurfa province has one of the widely populated areas in the region. Also, Sanliurfa is one of the biggest cities in southeast Turkey with population more than a million people. Not just enlarging the spanned area in terms of mapping the radioactivity background level of southeastern Turkey but also checking health hazard risk of people living in these less popular areas of Turkey were enough reason for us to accomplish this work. In the current study, 11 of soil, 7 of stone and 2 water samples were combined to assess the decay rates of previously mentioned nuclides, other health related indices and activity units which show effects in living things. The following text will present the outcome and some comparison with world average values to decide if any extra action is required to protect people’s health, or not. 2. Materials and Methods. With regard to measurement device, NaI(Tl) scintillation detector with the help of digibase MCA system provided by TAEK is used to get data points in time from our 6cmx5cm vegetation sample container. The digibase is a 14-pin photomultiplier tube base for gamma ray spectrometry. What’s unique about this system is that it combines its own preamplifier and detector high voltage (- to +1200V bias) together with multi-channel analyzer (MCA), powerful digitized signal processing, and special properties of fine time resolution measurements. All is provided by USB connection to a PC in a low -power (<500mA) with lightweight (280g) and small-size tube base (63.8 mm diameter x 80 mm length). Some specifications about performance is as follows: conversation gain of 1024 channels, fine gain of 0.5, shaping time 0.75μs and high actual voltage of 1198V. These values have been set up in advance according to detector’s manual which can be easily found online. The counting live time has been 86400s with low dead time. It’s crucial to keep the counting time high for having high statistics to increase the visibility of low-level gamma ray peaks in the spectrum due to the high background and electronic noise level. For data analysis software, Scintivision and Maestro were available in the laboratory, and the former one was used. There was no superiority of one to another except few options. Our detector system was surrounded and encapsulated inside about 5cm thick cylindrical lead shielding to minimize the background level from surrounding materials. For the preparation of soil and stone samples, it was important to select wide range of location to scan the region of Siverek. In total, 11 areas for soil and 7 areas for stone were decided as to be reference as listed in tables below. All samples were collected in uncultivated virgin lands near people’s settlement areas under 10 cm to 20 cm of ground level. Samples were kept in 15 days for air-drying. This procedure is to eliminate the moisture remained on the soil and to make grounding process easier afterwards. Next, samples were grounded in the automated mortar until homogenous mixture was reached. Those powder versions of the samples were put in the oven at 55-65 oC for one day. Lastly, these samples were sealed in 6cmx5cm containers to wait for 4 weeks to reach equilibrium state for 238U and 232Th with their measurable daughters with low half-lives [1]. Regarding the water sample preparation, 5 litres per each neighbourhood were sent to CNAEM laboratory. The details about the process were as follows: First, pH level of the samples was set below 2 with nitric-acid solution to avoid any sediment in the bottom of the containers. For a start, 20ml sample were vaporised, and the rest was heated in the oven at 105 oC during 15 minutes for balanced weight. After settling down in the room temperature, samples were vaporised at 60 oC until the volume decreases from 500 ml to 100 ml. The remnants were put on to the units of the measuring device in 20 cm3 pieces. Once the water on the samples were dismissed, they also kept in the oven at 105 oC for 2 hours again. To remove the humidity fully, desiccator was on samples. The detectable part of residue was weighted in the sensitive scaler until 140mg to avoid self-absorption of alpha particles in samples. Finally, the detector
Ilker Can Celik et al. / Procedia Computer Science 158 (2019) 125–134 Author name / Procedia Computer Science 00 (2019) 000–000
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of LB770-PC with 10 channels was in action. 3. Theory and Analysis Typically, a usual gamma spectral analysis requires the following steps: finding the peak locations, calculation of peak areas, correction of peak areas (reference peak correction for random summing losses or subtraction of system background can be made), calculation of the efficiency at the relevant peak energies, correcting for any branching ratios of a state, and finally the calculation of activity [4]. As a first step, detector is calibrated in terms of energy to locate the desired 1460keV gamma-ray peak originated from 40K through the beta minus decay by populating excited state of 40Ar, 1764keV and 2614keV gamma-ray peaks originated from respectively 214Bi and 208Tl. Both 1460 keV and 1764 keV peaks can be easily measurable because none of the other major peaks suffer from overlapping with adjacent peaks and being subject to significant summing. As to 2614 keV gamma-ray peak, 208Tl has large summing errors because all other nuclear de-excitations occur through that energy level [7]. Note that four nuclides can be detected easily in 232Th series by gamma spectrometry: 228Ac, 212Pb, 212Bi and 208Tl. In this chain, decay of 212Bi has a branching of % 64.06 and % 35.94 to populate states of 212Po and 208Tl. From that, 208Tl emits % 99.754 of the time gamma ray at 2614 keV. Therefore, the branching ratio and the gamma emission probability correction for the detected counts was necessary for the activity calculations. To manage efficiency and count calculation process, given sources of soil and tea samples with known activity by TAEK were used. After locating the interested peaks, net area calculations and corrections were processed. Over the years, gamma-ray spectroscopist have come up with some simple algorithms for peak area calculation. In the current study, 3 selected peaks were individually positioned, so the method was straight forward. The software Scintivision was used to get gross and the net areas with errors under each gamma-ray peak. To get the correct background subtraction, peak widths were kept large enough. After having the net counts from the samples, it was more useful to use the count rate (speed) by dividing into the detection time. Scientists mostly refer to this count rate term in their calculations rather than the counts itself. Another common terminology is to give calculated activity in terms of Bq/kg in unit. Thus, the activity calculations will be stated initially in Bq/kg unit, but then they will be converted to Gray and Sievert units by using proper coefficients and formulas stated in the following. 𝐵𝐵𝐵𝐵
𝐴𝐴 ( ) = 𝑘𝑘𝑘𝑘
Bq
𝑁𝑁(𝐸𝐸𝛾𝛾 ) 𝑡𝑡
×
1
𝜀𝜀(𝐸𝐸𝛾𝛾 )×𝐼𝐼(𝐸𝐸𝛾𝛾 )×𝑚𝑚
∆ε 2
∆N 2
∆I 2
∆A ( ) = A √( ) + ( ) + ( ) + ( kg
ε
N
I
∆m 2 m
∆t 2
) +( ) t
[9,11]
(1)
[6,21]
(2)
General activity and its error were calculated via the formula 1 and 2 as above. The corresponding values for soil and stone samples are written in the table 1. Each number refers to different location around the Siverek district. Eleven of which has names of Caylarbası (1), Karakeci (2), Baglar (3), Gurakar (4), Dagbası (5), Kuslugol (6), Karacadag (7), Buyukkazanlı (8), Cıkrık (9), Onder (10), and Ediz (11) respectively numbered for soil samples. On the other hand, numbers for stone samples were enumerated for the area names of Karacadag (1), Baglar (2), Dagbası (3), Sekerli (4), Buyukkazanlı (5), Ediz (6), and Onder (7). Table 2 to 4 use numbers instead of location names. According to UNSCEAR report Annex B [18], mean value of the population-weighted average activities of 238 U, 232Th and 40K are 35 Bq/kg, 30 Bq/kg and 400 Bq/kg in order. In addition, their activity ranges change as 17-60 Bq/kg, 11-64 Bq/kg and 140-850 Bq/kg, respectively. These values are referred in table 1 in the current study. In terms of individual data values in table 1, some activities might be slightly over the world average values. However, both the mean value of the data and some individual activities are below the desired values. Especially for 232Th and 40K, almost all values are below the world’s average activity for soil as stated by UNSCEAR’ report in 2000 [17]. For soil sample, Onder town had the only exceeding activity value with 507.82±45.04 Bq/kg. On the other hand, both Dagbası and Ediz towns had 413.61±37.59 Bq/kg and 635.43±55.07 Bq/kg surpassing activity values over world average. Ediz town has the dominant data in the data list for 40K. For 232Th list, Karakeci, Gurakar, Karacadag and Onder town exceeded the world average for soil, but only Ediz town went beyond the average as to stone. Moreover, Gurakar and Onder town has higher values of activity with respect to the world average for soil in terms of 238U activity. In summary, all those high values were indeed within the allowed activity range for the world’s data levels. Thus, all the
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data gave convincing results overall.
Table 1. Activities
U Series
238
Bi (Bq/kg)
Th Series
232
Tl (Bq/kg)
K
40
(Bq/kg) Soil Locations
214
208
(Bq/kg)
ÇAYLARBAŞI KARAKEÇİ BAĞLAR GÜRAKAR DAĞBAŞI KUŞLUGÖL KARACADAĞ BÜYÜKKAZANLI ÇIKRIK ÖNDER EDİZ
17.88±6.25 33.67±6.83 24.45±6.34 35.08±6.44 22.05±6.99 11.98±6.21 31.44±7.17 16.03±6.18 15.00±5.78 50.86±6.83 12.49±5.62
29.77±10.58 26.32±10.11 56.62±12.95 26.14±10.22 63.46±12.46 34.94±11.48 51.94±12.00 40.49±10.46 12.33±9.39 35.83±9.82 20.93±9.28
288.01±32.51 290.64±32.98 218.49±29.75 298.86±33.54 221.52±30.26 208.20±29.54 254.66±32.02 112.61±27.59 296.12±33.45 507.82±45.04 250.18±28.71
11.89±4.93 5.64±4.42 29.25±5.34 15.48±6.67 2.91±6.16 31.28±6.63 2.39±7.29 24.63±6.42 14.12±5.92 35 16-110
20.72±8.11 29.87±8.49 36.70±8.84 20.18±11.22 32.25±10.98 37.77±10.80 14.50±9.58 36.25±10.79 27.43±9.72 30 11-64
333.23±31.93 204.03±24.94 413.61±37.59 293.01±34.49 91.54±27.14 635.43±55.07 281.92±32.46 267.92±32.31 321.82±34.80 400 140-850
Stone Locations KARACADAĞ BAĞLAR DAĞBAŞI ŞEKERLİ BÜYÜKKAZANLI EDİZ ÖNDER Avg. Soil Activity Avg. Stone Activity World Average World Range
The values can be compared with the values in master thesis of “determination of natural radioactivity concentrations in Siverek town soil, water and stone samples” completed in Harran university in Turkey. World average and range activity levels can be accessed in UNSCEAR report [18].
3.1. Radium Equivalent Activity, Internal and External Hazard Indices Finding the activity was the first step in determining the radium equivalent dose and health hazard level of NORM samples. Based on the derived decay rates in table one, the formulas have been defined in the equations 3, 4 and 5. The coefficients besides the activities of Radium, which refers to 238U, 232Th and 40K come from the estimation that 10 Bq/kg of 226Ra, 7 Bq/kg of 232Th and 130 Bq/kg of 40K produce the same amount of gamma-ray dose. These ratios might change in years, for instance, according to OECD report in 1979 [12], Kriger’s article in 1981 [10] or article of Beretka & Mathew in 1985 [3]. The world allowed value for radium equivalent activity is 370 Bq/kg according to UNSCEAR reports in 1993 [16] and 2000 [17]. Both individual and the average results show promising outcome in comparison to the allowed value. Even the half of the allowed value was not exceeded at all. In comparison to soil samples, stone had %22 lower activity than the soil values in average.
Ilker Can Celik et al. / Procedia Computer Science 158 (2019) 125–134 Author name / Procedia Computer Science 00 (2019) 000–000
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On the other hand, internal and external hazard indices are a criterion for radiation hazard for people. For the human health safety, some parameters are served through the articles in years. The main one was presented by Kriger in 1981 [10] while the assumption of keeping the samples in a room with thick walls without doors and windows. The UNSCEAR report in 1982 [14] stated that only few measurements of NORM samples in building materials would not comply with the standard level of 1 or lesser values according to National Commission of Radiation Protection of USSR. In summary, all parameters have safe indices for health hazard perspective in table 2. (3)
Raequivalent = 𝐴𝐴𝑅𝑅𝑅𝑅 + 1.43 ATh + 0.077 𝐴𝐴𝐾𝐾 ARa
+
259(
ARa
+
259(
Hinternal =
159(
Hexternal =
370(
𝐵𝐵𝐵𝐵 ) 𝑘𝑘𝑘𝑘
𝐵𝐵𝐵𝐵 ) 𝑘𝑘𝑘𝑘
ATh
+
4810(
ATh
+
4810(
𝐵𝐵𝐵𝐵 ) 𝑘𝑘𝑘𝑘
𝐵𝐵𝐵𝐵 ) 𝑘𝑘𝑘𝑘
AK
𝐵𝐵𝐵𝐵 ) 𝑘𝑘𝑘𝑘
AK
𝐵𝐵𝐵𝐵 ) 𝑘𝑘𝑘𝑘
≤1
(4)
≤1
(5)
Table 2. Soil Sample No
Raequivalenta
Hinternalb
Hexternalb
(Bq/kg)
1
1 2 3 4 5 6 7 8 9 10 11 Mean Allowed Value Stone Sample No 1 2 3 4 5 6 7 Mean
77.52 96.85 108.40 99.31 112.05 68.11 116.51 72.09 56.58 147.66 58.06 92.10 370 Stone Sample
0.32 0.36 0.50 0.36 0.53 0.31 0.50 0.34 0.20 0.53 0.23 0.38 ≤1 Stone Sample
0.21 0.26 0.29 0.27 0.30 0.18 0.31 0.19 0.15 0.40 0.16 0.25 ≤1 Stone Sample
63.39 53.65 110.37 64.88 43.46 131.43 39.62 72.40
0.25 0.25 0.43 0.25 0.23 0.49 0.16 0.29
0.17 0.14 0.30 0.18 0.12 0.35 0.11 0.20
Formulas are used as in these references: a Beretka & Mathew 1983 [3]; bKriger. 1981 [10]; Apaydın et al., 2019 [2]; Eke, 2017 [5]. Allowed values are valid for both soil and stone samples.
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3.2. Indoor and Outdoor Absorbed Dose Rates In general, the absorbed dose is one of the fundamental dosimetry quantities in radiological protection purposes. This dose is defined as the energy absorbed per unit mass in unit of joule/kg, which has a special name of Gray (Gy) by ICRP publication 60 [8]. There are certain conversion coefficients that academicians refer. These numbers were exposed some changes over the years. Thus, three different outdoor absorbed doses and one indoor dose were calculated to see the proximity among them by using the formula 6 [15], 7 [17,18], 8 [3,13] and 9 [3,13] as given in table 3. According to the outcome, three outdoor doses had a proximity to each other. Outdoor doses calculations from UNSCEAR 1998, UNSCEAR 2000, UNSCEAR ANNEX B 2008, Beretka & Mathew and Qureshi had approximately similar average results under the World’s average value of 59 nGy/h for outdoor and 84 nGy/h for indoor stated in UNSCEAR report in 2000. D(
D(
nGy h
nGy h
) = 0.427 ( ) = 0.462 (
Dindoor−external (
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
nGy h
Doutdoor−external (
𝐵𝐵𝐵𝐵
) AU ( ) + 0.662 ( 𝑘𝑘𝑘𝑘
𝐵𝐵𝐵𝐵
) AU ( ) + 0.604 ( 𝑘𝑘𝑘𝑘
) = 0.92 (
nGy h
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
) = 0.436 (
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
𝐵𝐵𝐵𝐵
ℎ 𝐵𝐵𝐵𝐵
𝐵𝐵𝐵𝐵
) ATh ( ) + 0.043 ( 𝑘𝑘𝑘𝑘
𝐵𝐵𝐵𝐵
) ATh ( ) + 0.0417 (
) ARa ( ) + 1.1 (
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
𝑘𝑘𝑘𝑘
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
𝐵𝐵𝐵𝐵
𝑘𝑘𝑘𝑘
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
) ARa ( ) + 0.599 ( 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
𝐵𝐵𝐵𝐵
ℎ 𝐵𝐵𝐵𝐵
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
𝐵𝐵𝐵𝐵
(6)
𝐵𝐵𝐵𝐵
(7)
𝑘𝑘𝑘𝑘
) AK ( )
) ATh ( ) + 0.081 ( 𝑘𝑘𝑘𝑘
𝐵𝐵𝐵𝐵
) AK ( ) 𝑘𝑘𝑘𝑘
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
) ATh ( ) + 0.0417 ( 𝑘𝑘𝑘𝑘
𝐵𝐵𝐵𝐵
) AK ( ) 𝑘𝑘𝑘𝑘
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
(8) 𝐵𝐵𝐵𝐵
) AK ( ) (9) 𝑘𝑘𝑘𝑘
3.3. Indoor and Outdoor External Annual Effective Doses The annual effective dose is the summation of the dose from external exposure and committed dose by means of both inhalation and ingestion throughout the year according to UNSCEAR Annex B report in 2016 [20]. Depending on indoor and outdoor time spent, the %20 and %80 ratios will be applied in the calculations as put in equations 8 and 9. As far as the definition states, 8760s is the amount of time in 1 year as another conversion factor. Finally, the unit conversion from Gy to Sievert (Sv) was done with 0.7 (Sv/Gy) coefficient decided in UNSCEAR reports. The Sievert has normally the weighting factor in it to differ the radiation dose depending on the radiation type and the effected live tissue. Thus, it is more relevant to a biological effect of ionizing radiation. Also, it is used to assess how much risk the radiation possesses to living organisms in terms of cancer and genetic damage. According to UNSCEAR report in 2000 [17], the world’s average for indoor and outdoor external annual effective dose (AED) were respectively 410 μSv/y and 70 μSv/y. As shown in table 4, average values for both soil and stone were below the allowed value of world’ average.
AEDindoor−external (
μSv y
AEDoutdoor−external (
) = Dindoor (
μSv y
nGy h
) = Doutdoor (
) × 8760 (h) ×
nGy h
80
100
) × 8760 (h) ×
Sv
× 0.7 ( ) × 103
20
100
Gy
Sv
× 0.7 ( ) × 103 Gy
(10)
(11)
3.4. Excess Lifetime Cancer Risks As the formulas 12 and 13 indicates, life expectancy (LE) and risk factor (RF) are the common parts of the equations. Life expectancy of a country might change from country to country in various reasons. However, LE was taken as at least 78 for people with healthy life style in Turkey. Risk factor was given as 0.05 by ICRP publication 60
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[8]. In addition, world average for indoor and outdoor ELCR was indicated as 2840 μSv and 370 μSv by Qureshi et al, 2014 [13]. When table 4 was checked, all values for soil and stone were below this average value. ELCR indoor (μSv) = AEDindoor−external (
μSv y
ELCR outdoor (μSv) = AEDoutdoor−external (
(12)
) × LE × RF
μSv y
(13)
) × LE × RF
Table 3. Soil Sample No
Doutdoor_external a (nGy/h)
Doutdoor_externalb
Doutdoor_externalc
Dindoor_externalc
(nGy/h)
(nGy/h)
35.70 43.76 48.44 44.87 50.12 31.09 52.10 31.95 26.71 67.26 27.04
70.39 84.79 96.68 86.84 100.58 62.19 103.00 64.01 51.83 130.04 53.27
41.73
82.15
59
84
1 2 3 4 5 6 7 8 9 10 11
36.93 46.03 49.76 47.23 51.22 31.81 53.94 32.74 27.93 70.80 27.97
(nGy/h) 36.57 44.62 50.04 45.73 51.88 32.06 53.61 33.08 27.11 68.45 27.65
Mean
43.31
42.80
World Average
59
59
31.05 25.26 52.82 31.46 19.63 64.16 19.89
30.65 25.72 51.87 30.89 20.48 62.84 19.90
30.06 24.91 50.77 30.29 19.62 61.70 19.51
59.14 50.21 99.44 59.33 40.29 120.62 38.80
34.90
34.62
33.84
66.83
Stone Sample No 1 2 3 4 5 6 7 Mean
Formulas are used as in these references: a UNSCEAR 1988 [15], b UNSCEAR 2000 [17]; UNSCEAR ANNEX B 2008 [19], c Beretka & Mathew 1985 [3]; Qureshi, 2014 [13]. World average is regarded as the same for both soil and stone.
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Ilker Can Celik / Procedia Computer Science 00 (2019) 000–000 Ilker Can Celik et al. / Procedia Computer Science 158 (2019) 125–134
Table 4.
Soil Sample No 1 2 3 4 5 6 7 8 9 10 11 Mean W. A. Stone Sample No 1 2 13 4 5 6 7 Mean
AEDindoor_external a,b
AEDoutdoor_externala,b AEDoutdoor_externala,b,c
ELCRindoorb,d
ELCRoutdoorb,d
(μSv/y) 345.30 415.96 474.28 426.00 493.43 305.09 505.27 313.99 254.27 637.93 261.31 402.98 410
(μSv/y) 45.30 56.45 61.02 57.93 62.82 39.01 66.15 40.16 34.25 86.83 34.30 53.11 70
(μSv/y) 43.78 53.67 59.41 55.03 61.46 38.13 63.89 39.19 32.76 82.49 33.17 51.18 70
(μSv) 1346.66 1622.26 1849.69 1661.41 1924.38 1189.86 1970.54 1224.56 991.65 2487.93 1019.11 1571.64 2840b
(μSv) 170.76 209.32 231.69 214.61 239.70 148.73 249.18 152.83 127.76 321.71 129.35 199.60 370b
Stone Sample
Stone Sample
Stone Sample
Stone Sample
Stone Sample
249.01 290.12 246.32 487.81 291.04 197.64 591.73 190.33 327.85
38.08 30.98 64.78 38.59 24.08 78.68 24.40 42.80
36.86 30.55 62.26 37.15 24.07 75.67 23.92 41.50
1131.47 960.64 1902.46 1135.05 770.78 2307.75 742.28 1278.63
143.76 119.14 242.82 144.88 93.85 295.11 93.30 161.84
Formulas are used as in these references: a UNSCEAR (2000) [17], bQuereshi (2014) [13], cUNSCEAR (1988) [15], d ICRP (1991) [8]. For the column 2, the Doutdoor_external values are calculated with equation in UNSCEAR report in 1988 [15]. W.A. stands for world average stated by UNSCEAR report in 2000 [17].
3.5. Gross Alpha and Beta Activity in water According to guidelines for drinking water quality report published by WHO in 2011 [22], the most common approach was to look at the residue activity after evaporating known value of a water sample. That was all done for our samples by CNAEM. The health safety procedure stated in the same report was that no further action was necessary if gross alpha activity was either lesser than 0.5 Bq/L or equal to 0.5 Bq/L. On the other hand, same was valid if the gross beta activity was either lesser than 1 Bq/L or equal to 1 Bq/L. On the contrary, it was necessary to determine individual radionuclide concentrations and to compare with guidance levels if gross alpha activity is higher than 0.5 Bq/L and gross beta activity is higher than 1Bq/L. Then, water would be regarded as suitable for use if dose
Ilker Can Celik et al. / Procedia Computer Science 158 (2019) 125–134 Author name / Procedia Computer Science 00 (2019) 000–000
133 9
is lesser than 0.1mSv or equal to it. Otherwise, it should be considered to take remedial action to reduce the dose. When all these perspectives were considered, the results in table 5 was below the maximum level of health risk. Table 5. Water Sample Dagbası Baglar WHOa
Total α activity concentration (Bq/L)
MDA
0.02±0.01 0.03±0.01 Max 0.5
0.01 0.01
Total β activity concentration (Bq/L) 0.06±0.02 0.22±0.03 Max 1
MDA 0.02 0.02
Dagbası and Baglar are the names of neighborhoods of Siverek town of Sanlıurfa province. aWHO refers to the report published in 2011 [22] under the title of “Guidelines for drinking water quality, 3rd Edition”.
4. Conclusion In the current study, widely used NaI(Tl) detector was employed for gamma-ray spectrometry. The purpose was to detect some NORM in soil, stone and water samples in Siverek region in Sanlıurfa, Turkey. Thus, 11 soil, 7 stone and 2 water samples were analysed through their decay rates to give us more meaningful data in human health perspective. Various published articles and reports were scanned to get the precise world widely accepted information. For the current data, focus was on 214Bi for 238U activity, 208Tl for 232Th activity and another activity for widely encountered radionuclide of 40K. In summary, average measurements of all 11 and 7 samples from soil and stone were under the world average activities as shown in table 1. In addition, gross alpha and beta activities for water samples were checked to be within the allowed values of 0.5 Bq/L and 1 Bq/L as stated by WHO. To evaluate the radiological impact of these samples, distinct units of activities were calculated to compare with world’s standards. Among them, Raequivalent activity, Hinternal and Hexternal indices, indoor and outdoor absorbed dose rates, indoor and outdoor external AED, indoor and outdoor ELCR levels can be listed. In summary, most of the data points and all average measurement outcomes turned out to be inside the allowed values given by organizations like WHO, UNSCEAR, ICRP even though some of the individual parameters showed slightly over the world average desired values. Acknowledgements I’d like to thank former master student Mehmet Altıntas in Harran University for data collection and processing steps. References [1] Altıntas, M. (2018). Determination of natural radioactivity concentrations in Siverek town soil, water and stone samples. (Unpublished master’s thesis). Harran University, Sanliurfa, Turkey. [2] Apaydın, G. , Köksal, O. K. , Cengiz, E. , Tırasoğlu, E. , Baltaş, H. , Karabulut, K., et al. (2019). Assessment of natural radioactivity and radiological risk of sediment samples in Karacaören II dam Lake, Isparta/Turkey. ALKÜ Fen Bilimleri Dergisi, 28-35. Retrieved from http://dergipark.gov.tr/alku/issue/41490/492920. [3] Beretka,J.&Mathew, P.J. (1985). Natural radioactivity of Australian building materials, industrial wastes and by-products. Health Phys. 48, 87. [4] Diehl, J. (2004). Handbook of radioactivity analysis. 2. Aufl., Herausgegeben von Michael F. L'Annunziata. Angewandte Chemie, 116(13), pp.1647-1647. [5] Eke, C. (2017). Determination of activity concentrations of natural and artificial radionuclides in some commercial salt samples. Sakarya University Journal of Science, 21 (6), 1422-1433. DOI: 10.16984/saufenbilder.305792. [6] Gezer, F., Turhan, Ş., Uğur, F., Gören, E., Kurt, M. & Ufuktepe, Y. (2012). Natural radionuclide content of disposed phosphogypsum as TENORM produced from phosphorus fertilizer industry in Turkey. Annals of
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Nuclear Energy, 50, 33-37. [7] Gilmore, G. R. (2008). Practical Gamma-ray Spectrometry, 2nd Edition. Chichester, West Sussex, England: John Wiley & Sons (Eds.). ISBN: 978-0-470-86196-7. [8] ICRP, 1991. 1990 Recommendations of the International Commission on Radiological Protection. ICRP Publication 60. Ann. ICRP 21 (1-3). [9] Ilker Can Celik. (2014). A particle-𝛾𝛾 coincidence study of 26Na using the transfer reaction 25Na(d,p γ)26Na. (Doctoral thesis, University of Surrey). Retrieved from personal.ph.surrey.ac.uk/~phs1wc/report/CelikPhD-Thesis-2014.pdf. [10] Krieger, R. (1981) Radioactivity of Construction Materials. Betonwerk und Fertigteil-Technik/Concrete Precasting Plant and Technology, 47, 468-446. [11] Nyanda, P.B. & Nkuba, L. L. (2017) Natural radioactivity in vegetables from selected areas of Manyoni District in Central Tanzania. Physical Science International Journal, 16 (2), 4. [12] OECD Nuclear Energy Agency. (1979, May). Exposure to radiation from the natural radioactivity in building materials. Nuclear Energy Agency Organisation for Economic Co-operation and Development. [13] Qureshi, A. A., Tariq, S., Din, K.U., Manzoor, S., Calligaris, C. & Waheed, A. (2014). Evaluation of excessive lifetime cancer risk due to natural radioactivity in the river’s sediments of Northern Pakistan. Journal of Radiation Research and Applied Sciences, Volume 7, Issue 4. Pages 438-447. [14] UNSCEAR. (1982). Ionizing Radiation: Sources and Biological Effects. United Nations Scientific Committee on the Effect of Atomic Radiation 1982 Report to General Assembly, with Annexes. United Nations, New York. [15] UNSCEAR. (1988). Sources, Effects and Risks of Ionizing Radiation. United Nations Committee on the Effects of Atomic Radiation 1988 Report to General Assembly, with Annexes. United Nations, New York. [16] UNSCEAR. (1993). United Nations Scientific Committee on the Effects of Atomic Radiation. Sources, Effects and Risks of Ionizing Radiation. Report to the General Assembly with Scientific Annexes, United Nations, New York, 183-184. [17] UNSCEAR. (2000). United Nations Scientific Committee on the Effect of Atomic Radiation, Radiation sources and Effects of ionizing radiation. Report to General Assembly, with Scientific Annexes. United Nations, New York. [18] UNSCEAR (2000) Annex B: Exposure from Natural Radiation Sources. Report to General Assembly, United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), New York. [19] UNSCEAR. (2008). Sources and Effects of Ionizing Radiation. United Nations Committee on the Effects of Atomic Radiation. Report to General Assembly with Annexes. Volume 1, Annex B, Exposures of the public and workers from various sources of radiation. United Nations, New York. [20] UNSCEAR. (2016). Sources, Effects and Risks of Ionizing Radiation. United Nations Committee on the Effects of Atomic Radiation. Report to General Assembly with Annexes. Scientific Annex B, Radiation Exposures from Electricity Generation. United Nations, New York. [21] Yıldız, N., Oto, B. , Turhan, Ş., Uğur, F.A., Gören, E. (2014). Radionuclide determination and radioactivity evaluation of surface soil samples collected along the Erçek Lake basin in eastern Anatolia, Turkey. Journal of Geochemical Exploration, 146, 36. [22] World Health Organization. (2011). Guidelines for drinking-water quality, 4th ed. Geneva: World Health Organization
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ScienceDirect Procedia Computer Science 158 (2019) 125–134
3rd World Conference on Technology, Innovation and Entrepreneurship (WOCTINE) 3rd World Conference on Technology, Innovation and Entrepreneurship (WOCTINE) Assessment of Environmental Radioactivity and Health Hazard in Soil, Water, Stone Samples in Siverekand Town of Sanliurfa Assessment of and Environmental Radioactivity Health Hazard in Province in Southeastern Turkey Soil, Water, and Stone Samples in Siverek Town of Sanliurfa Province inCelik Southeastern Turkey , Ilker Can , Mehmet Kosal 1*
Abstract
1
Ilker Can Celik , Mehmet Kosal
1
1,* 1 Faculty of Arts and Sciences, Department of Physics, Harran University, 63300 Sanliurfa, Turkey
1
Faculty of Arts and Sciences, Department of Physics, Harran University, 63300 Sanliurfa, Turkey
Human life depends on water and soil where our food mostly needs to be grown. Let us not forget the nature and rocks that we Abstract are surrounded in terms of structural base. For that reason, it’s crucial to determine their radioactivity level not just to help mapping the Human country’s measurements, but to assess and protection. the International liferadiation dependsbackground on water and soil where our food mostlypeople’s needs tosafety be grown. Let us notEspecially, forget the nature and rocks Atomic that we Energy Agencyin(IAEA), United Nations Scientific Committee on the Effects oftheir Atomic Radiationlevel (UNSCEAR), Health are surrounded terms ofthe structural base. For that reason, it’s crucial to determine radioactivity not just to World help mapping Organization (WHO), or the International Commission Radiological Protection (ICRP) develop safetythe standards to protect the the country’s radiation background measurements, but toon assess people’s safety and protection. Especially, International Atomic health and to minimize people’s life before anything happens. specific study, (UNSCEAR), the most densely populated Energy Agency (IAEA),the the danger United for Nations Scientific Committee on the EffectsInofthis Atomic Radiation World Health county, called(WHO), Siverek,orinthe theInternational region of Sanliurfa municipality was selected. For the(ICRP) analysis of soil safety and rock, respectively 11 and Organization Commission on Radiological Protection develop standards to protect the 7health distinctive determine activity levelshappens. in HarranInUniversity laboratory. to water samples, only and tolocations minimizewere the considered danger for to people’s life the before anything this specific study, theAsmost densely populated two samples were proceeded detectof total alpha and beta activities Cekmece Research andand Education Centre (CNAEM) county, called Siverek, in thetoregion Sanliurfa municipality wasby selected. ForNuclear the analysis of soil rock, respectively 11 and by Turkish Atomic Energy (TAEK). 7 distinctive locations wereAgency considered to determine the activity levels in Harran University laboratory. As to water samples, only regard analysis tools, Ortec used Research to detect and anyEducation activity based naturally twoWith samples weretoproceeded to detect totalbrand alphaNaI(Tl) and betascintillation activities bydetector Cekmecewas Nuclear Centreon(CNAEM) occurring materials (NORM), such as 238U, 232Th, and 40K elements in soil and stone samples with the help of digibase by Turkishradioactive Atomic Energy Agency (TAEK). MCA system. activity investigation, low-level activity measurement system of LB770-PC withbased 10 channels, were With regardFor to water analysis tools,level Ortec brand NaI(Tl) scintillation detector was used to detect any activity on naturally used. occurring radioactive materials (NORM), such as 238U, 232Th, and 40K elements in soil and stone samples with the help of digibase As system. a result,For it’s water expected to find theinvestigation, levels of the low-level most encountered activity units;system such asofRadium equivalent indoorwere and MCA activity level activity measurement LB770-PC with 10dose, channels, outdoor used. external absorbed doses, internal and external hazard indices, indoor and outdoor annual effective doses, indoor and outdoor life-time cancer risksthe lower than that some organizations stated literature. As a excess result, it’s expected to find levels of the the values most encountered activity units; suchinastheir Radium equivalent dose, indoor and outdoor external absorbed doses, internal and external hazard indices, indoor and outdoor annual effective doses, indoor and outdoor excess life-time cancer risks lower than the values that some organizations stated in their literature. © 2019 The Author(s). Published by Elsevier B.V. © 2019 The Authors. Published by of Elsevier B.V. Peer-review under responsibility the scientific committee of the 3rd World Conference on Technology, Innovation and Peer-review under responsibility of the scientific committee of the 3rd World Conference on Technology, Innovation and © 2019 The Author(s). Published by Elsevier B.V. Entrepreneurship Entrepreneurship Peer-review under responsibility of the scientific committee of the 3rd World Conference on Technology, Innovation and Keywords: NaI(Tl) detector; Siverek; Sanliurfa; NORM; UNSCEAR; WHO; ICRP; IAEA; Activity units. Entrepreneurship * Corresponding author.detector; E-mail address: [email protected] Keywords: NaI(Tl) Siverek; Sanliurfa; NORM; UNSCEAR; WHO; ICRP; IAEA; Activity units. * Corresponding author. E-mail address: [email protected]
1877-0509 © 2019 The Author(s). Published by Elsevier B.V. Peer-review under responsibility of the scientific committee of the 3rd World Conference on Technology, Innovation and Entrepreneurship 1877-0509 © 2019 The Author(s). Published by Elsevier B.V. Peer-review under responsibility of the scientific committee of the 3rd World Conference on Technology, Innovation and Entrepreneurship
1877-0509 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the scientific committee of the 3rd World Conference on Technology, Innovation and Entrepreneurship 10.1016/j.procs.2019.09.035
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Ilker Can Celik et al. / Procedia Computer Science 158 (2019) 125–134 Ilker Can Celik / Procedia Computer Science 00 (2019) 000–000
1. Introduction Living organisms are exposed to radiation by naturally occurring radioactive materials or man-made radioactive products. In this study, our work was focused on the natural side of the cause. Therefore, investigation took place in soil, stone and water samples due to their vast amounts in our surroundings as human beings. These primordial radionuclides have long enough half-lives that they still exist since the beginning of the Earth. Moreover, it’s possible to calculate their activities from their daughter nuclei in their decay chains. Both shorter half-lives of these daughter nuclide and their radioactivity traces are detectable with current technology. That enables us to study them as a physicist. For that reason, it’s crucial to know at what level they have possibility to harm us through our lifespan. Careful investigations have been ongoing for many years to detect mainly the activity levels by means of either gamma-ray in 238U, 232Th, 40K or alpha and beta activities in natural formations. Siverek town of Sanliurfa province has one of the widely populated areas in the region. Also, Sanliurfa is one of the biggest cities in southeast Turkey with population more than a million people. Not just enlarging the spanned area in terms of mapping the radioactivity background level of southeastern Turkey but also checking health hazard risk of people living in these less popular areas of Turkey were enough reason for us to accomplish this work. In the current study, 11 of soil, 7 of stone and 2 water samples were combined to assess the decay rates of previously mentioned nuclides, other health related indices and activity units which show effects in living things. The following text will present the outcome and some comparison with world average values to decide if any extra action is required to protect people’s health, or not. 2. Materials and Methods. With regard to measurement device, NaI(Tl) scintillation detector with the help of digibase MCA system provided by TAEK is used to get data points in time from our 6cmx5cm vegetation sample container. The digibase is a 14-pin photomultiplier tube base for gamma ray spectrometry. What’s unique about this system is that it combines its own preamplifier and detector high voltage (- to +1200V bias) together with multi-channel analyzer (MCA), powerful digitized signal processing, and special properties of fine time resolution measurements. All is provided by USB connection to a PC in a low -power (<500mA) with lightweight (280g) and small-size tube base (63.8 mm diameter x 80 mm length). Some specifications about performance is as follows: conversation gain of 1024 channels, fine gain of 0.5, shaping time 0.75μs and high actual voltage of 1198V. These values have been set up in advance according to detector’s manual which can be easily found online. The counting live time has been 86400s with low dead time. It’s crucial to keep the counting time high for having high statistics to increase the visibility of low-level gamma ray peaks in the spectrum due to the high background and electronic noise level. For data analysis software, Scintivision and Maestro were available in the laboratory, and the former one was used. There was no superiority of one to another except few options. Our detector system was surrounded and encapsulated inside about 5cm thick cylindrical lead shielding to minimize the background level from surrounding materials. For the preparation of soil and stone samples, it was important to select wide range of location to scan the region of Siverek. In total, 11 areas for soil and 7 areas for stone were decided as to be reference as listed in tables below. All samples were collected in uncultivated virgin lands near people’s settlement areas under 10 cm to 20 cm of ground level. Samples were kept in 15 days for air-drying. This procedure is to eliminate the moisture remained on the soil and to make grounding process easier afterwards. Next, samples were grounded in the automated mortar until homogenous mixture was reached. Those powder versions of the samples were put in the oven at 55-65 oC for one day. Lastly, these samples were sealed in 6cmx5cm containers to wait for 4 weeks to reach equilibrium state for 238U and 232Th with their measurable daughters with low half-lives [1]. Regarding the water sample preparation, 5 litres per each neighbourhood were sent to CNAEM laboratory. The details about the process were as follows: First, pH level of the samples was set below 2 with nitric-acid solution to avoid any sediment in the bottom of the containers. For a start, 20ml sample were vaporised, and the rest was heated in the oven at 105 oC during 15 minutes for balanced weight. After settling down in the room temperature, samples were vaporised at 60 oC until the volume decreases from 500 ml to 100 ml. The remnants were put on to the units of the measuring device in 20 cm3 pieces. Once the water on the samples were dismissed, they also kept in the oven at 105 oC for 2 hours again. To remove the humidity fully, desiccator was on samples. The detectable part of residue was weighted in the sensitive scaler until 140mg to avoid self-absorption of alpha particles in samples. Finally, the detector
Ilker Can Celik et al. / Procedia Computer Science 158 (2019) 125–134 Author name / Procedia Computer Science 00 (2019) 000–000
127 3
of LB770-PC with 10 channels was in action. 3. Theory and Analysis Typically, a usual gamma spectral analysis requires the following steps: finding the peak locations, calculation of peak areas, correction of peak areas (reference peak correction for random summing losses or subtraction of system background can be made), calculation of the efficiency at the relevant peak energies, correcting for any branching ratios of a state, and finally the calculation of activity [4]. As a first step, detector is calibrated in terms of energy to locate the desired 1460keV gamma-ray peak originated from 40K through the beta minus decay by populating excited state of 40Ar, 1764keV and 2614keV gamma-ray peaks originated from respectively 214Bi and 208Tl. Both 1460 keV and 1764 keV peaks can be easily measurable because none of the other major peaks suffer from overlapping with adjacent peaks and being subject to significant summing. As to 2614 keV gamma-ray peak, 208Tl has large summing errors because all other nuclear de-excitations occur through that energy level [7]. Note that four nuclides can be detected easily in 232Th series by gamma spectrometry: 228Ac, 212Pb, 212Bi and 208Tl. In this chain, decay of 212Bi has a branching of % 64.06 and % 35.94 to populate states of 212Po and 208Tl. From that, 208Tl emits % 99.754 of the time gamma ray at 2614 keV. Therefore, the branching ratio and the gamma emission probability correction for the detected counts was necessary for the activity calculations. To manage efficiency and count calculation process, given sources of soil and tea samples with known activity by TAEK were used. After locating the interested peaks, net area calculations and corrections were processed. Over the years, gamma-ray spectroscopist have come up with some simple algorithms for peak area calculation. In the current study, 3 selected peaks were individually positioned, so the method was straight forward. The software Scintivision was used to get gross and the net areas with errors under each gamma-ray peak. To get the correct background subtraction, peak widths were kept large enough. After having the net counts from the samples, it was more useful to use the count rate (speed) by dividing into the detection time. Scientists mostly refer to this count rate term in their calculations rather than the counts itself. Another common terminology is to give calculated activity in terms of Bq/kg in unit. Thus, the activity calculations will be stated initially in Bq/kg unit, but then they will be converted to Gray and Sievert units by using proper coefficients and formulas stated in the following. 𝐵𝐵𝐵𝐵
𝐴𝐴 ( ) = 𝑘𝑘𝑘𝑘
Bq
𝑁𝑁(𝐸𝐸𝛾𝛾 ) 𝑡𝑡
×
1
𝜀𝜀(𝐸𝐸𝛾𝛾 )×𝐼𝐼(𝐸𝐸𝛾𝛾 )×𝑚𝑚
∆ε 2
∆N 2
∆I 2
∆A ( ) = A √( ) + ( ) + ( ) + ( kg
ε
N
I
∆m 2 m
∆t 2
) +( ) t
[9,11]
(1)
[6,21]
(2)
General activity and its error were calculated via the formula 1 and 2 as above. The corresponding values for soil and stone samples are written in the table 1. Each number refers to different location around the Siverek district. Eleven of which has names of Caylarbası (1), Karakeci (2), Baglar (3), Gurakar (4), Dagbası (5), Kuslugol (6), Karacadag (7), Buyukkazanlı (8), Cıkrık (9), Onder (10), and Ediz (11) respectively numbered for soil samples. On the other hand, numbers for stone samples were enumerated for the area names of Karacadag (1), Baglar (2), Dagbası (3), Sekerli (4), Buyukkazanlı (5), Ediz (6), and Onder (7). Table 2 to 4 use numbers instead of location names. According to UNSCEAR report Annex B [18], mean value of the population-weighted average activities of 238 U, 232Th and 40K are 35 Bq/kg, 30 Bq/kg and 400 Bq/kg in order. In addition, their activity ranges change as 17-60 Bq/kg, 11-64 Bq/kg and 140-850 Bq/kg, respectively. These values are referred in table 1 in the current study. In terms of individual data values in table 1, some activities might be slightly over the world average values. However, both the mean value of the data and some individual activities are below the desired values. Especially for 232Th and 40K, almost all values are below the world’s average activity for soil as stated by UNSCEAR’ report in 2000 [17]. For soil sample, Onder town had the only exceeding activity value with 507.82±45.04 Bq/kg. On the other hand, both Dagbası and Ediz towns had 413.61±37.59 Bq/kg and 635.43±55.07 Bq/kg surpassing activity values over world average. Ediz town has the dominant data in the data list for 40K. For 232Th list, Karakeci, Gurakar, Karacadag and Onder town exceeded the world average for soil, but only Ediz town went beyond the average as to stone. Moreover, Gurakar and Onder town has higher values of activity with respect to the world average for soil in terms of 238U activity. In summary, all those high values were indeed within the allowed activity range for the world’s data levels. Thus, all the
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data gave convincing results overall.
Table 1. Activities
U Series
238
Bi (Bq/kg)
Th Series
232
Tl (Bq/kg)
K
40
(Bq/kg) Soil Locations
214
208
(Bq/kg)
ÇAYLARBAŞI KARAKEÇİ BAĞLAR GÜRAKAR DAĞBAŞI KUŞLUGÖL KARACADAĞ BÜYÜKKAZANLI ÇIKRIK ÖNDER EDİZ
17.88±6.25 33.67±6.83 24.45±6.34 35.08±6.44 22.05±6.99 11.98±6.21 31.44±7.17 16.03±6.18 15.00±5.78 50.86±6.83 12.49±5.62
29.77±10.58 26.32±10.11 56.62±12.95 26.14±10.22 63.46±12.46 34.94±11.48 51.94±12.00 40.49±10.46 12.33±9.39 35.83±9.82 20.93±9.28
288.01±32.51 290.64±32.98 218.49±29.75 298.86±33.54 221.52±30.26 208.20±29.54 254.66±32.02 112.61±27.59 296.12±33.45 507.82±45.04 250.18±28.71
11.89±4.93 5.64±4.42 29.25±5.34 15.48±6.67 2.91±6.16 31.28±6.63 2.39±7.29 24.63±6.42 14.12±5.92 35 16-110
20.72±8.11 29.87±8.49 36.70±8.84 20.18±11.22 32.25±10.98 37.77±10.80 14.50±9.58 36.25±10.79 27.43±9.72 30 11-64
333.23±31.93 204.03±24.94 413.61±37.59 293.01±34.49 91.54±27.14 635.43±55.07 281.92±32.46 267.92±32.31 321.82±34.80 400 140-850
Stone Locations KARACADAĞ BAĞLAR DAĞBAŞI ŞEKERLİ BÜYÜKKAZANLI EDİZ ÖNDER Avg. Soil Activity Avg. Stone Activity World Average World Range
The values can be compared with the values in master thesis of “determination of natural radioactivity concentrations in Siverek town soil, water and stone samples” completed in Harran university in Turkey. World average and range activity levels can be accessed in UNSCEAR report [18].
3.1. Radium Equivalent Activity, Internal and External Hazard Indices Finding the activity was the first step in determining the radium equivalent dose and health hazard level of NORM samples. Based on the derived decay rates in table one, the formulas have been defined in the equations 3, 4 and 5. The coefficients besides the activities of Radium, which refers to 238U, 232Th and 40K come from the estimation that 10 Bq/kg of 226Ra, 7 Bq/kg of 232Th and 130 Bq/kg of 40K produce the same amount of gamma-ray dose. These ratios might change in years, for instance, according to OECD report in 1979 [12], Kriger’s article in 1981 [10] or article of Beretka & Mathew in 1985 [3]. The world allowed value for radium equivalent activity is 370 Bq/kg according to UNSCEAR reports in 1993 [16] and 2000 [17]. Both individual and the average results show promising outcome in comparison to the allowed value. Even the half of the allowed value was not exceeded at all. In comparison to soil samples, stone had %22 lower activity than the soil values in average.
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On the other hand, internal and external hazard indices are a criterion for radiation hazard for people. For the human health safety, some parameters are served through the articles in years. The main one was presented by Kriger in 1981 [10] while the assumption of keeping the samples in a room with thick walls without doors and windows. The UNSCEAR report in 1982 [14] stated that only few measurements of NORM samples in building materials would not comply with the standard level of 1 or lesser values according to National Commission of Radiation Protection of USSR. In summary, all parameters have safe indices for health hazard perspective in table 2. (3)
Raequivalent = 𝐴𝐴𝑅𝑅𝑅𝑅 + 1.43 ATh + 0.077 𝐴𝐴𝐾𝐾 ARa
+
259(
ARa
+
259(
Hinternal =
159(
Hexternal =
370(
𝐵𝐵𝐵𝐵 ) 𝑘𝑘𝑘𝑘
𝐵𝐵𝐵𝐵 ) 𝑘𝑘𝑘𝑘
ATh
+
4810(
ATh
+
4810(
𝐵𝐵𝐵𝐵 ) 𝑘𝑘𝑘𝑘
𝐵𝐵𝐵𝐵 ) 𝑘𝑘𝑘𝑘
AK
𝐵𝐵𝐵𝐵 ) 𝑘𝑘𝑘𝑘
AK
𝐵𝐵𝐵𝐵 ) 𝑘𝑘𝑘𝑘
≤1
(4)
≤1
(5)
Table 2. Soil Sample No
Raequivalenta
Hinternalb
Hexternalb
(Bq/kg)
1
1 2 3 4 5 6 7 8 9 10 11 Mean Allowed Value Stone Sample No 1 2 3 4 5 6 7 Mean
77.52 96.85 108.40 99.31 112.05 68.11 116.51 72.09 56.58 147.66 58.06 92.10 370 Stone Sample
0.32 0.36 0.50 0.36 0.53 0.31 0.50 0.34 0.20 0.53 0.23 0.38 ≤1 Stone Sample
0.21 0.26 0.29 0.27 0.30 0.18 0.31 0.19 0.15 0.40 0.16 0.25 ≤1 Stone Sample
63.39 53.65 110.37 64.88 43.46 131.43 39.62 72.40
0.25 0.25 0.43 0.25 0.23 0.49 0.16 0.29
0.17 0.14 0.30 0.18 0.12 0.35 0.11 0.20
Formulas are used as in these references: a Beretka & Mathew 1983 [3]; bKriger. 1981 [10]; Apaydın et al., 2019 [2]; Eke, 2017 [5]. Allowed values are valid for both soil and stone samples.
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3.2. Indoor and Outdoor Absorbed Dose Rates In general, the absorbed dose is one of the fundamental dosimetry quantities in radiological protection purposes. This dose is defined as the energy absorbed per unit mass in unit of joule/kg, which has a special name of Gray (Gy) by ICRP publication 60 [8]. There are certain conversion coefficients that academicians refer. These numbers were exposed some changes over the years. Thus, three different outdoor absorbed doses and one indoor dose were calculated to see the proximity among them by using the formula 6 [15], 7 [17,18], 8 [3,13] and 9 [3,13] as given in table 3. According to the outcome, three outdoor doses had a proximity to each other. Outdoor doses calculations from UNSCEAR 1998, UNSCEAR 2000, UNSCEAR ANNEX B 2008, Beretka & Mathew and Qureshi had approximately similar average results under the World’s average value of 59 nGy/h for outdoor and 84 nGy/h for indoor stated in UNSCEAR report in 2000. D(
D(
nGy h
nGy h
) = 0.427 ( ) = 0.462 (
Dindoor−external (
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
nGy h
Doutdoor−external (
𝐵𝐵𝐵𝐵
) AU ( ) + 0.662 ( 𝑘𝑘𝑘𝑘
𝐵𝐵𝐵𝐵
) AU ( ) + 0.604 ( 𝑘𝑘𝑘𝑘
) = 0.92 (
nGy h
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
) = 0.436 (
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
𝐵𝐵𝐵𝐵
ℎ 𝐵𝐵𝐵𝐵
𝐵𝐵𝐵𝐵
) ATh ( ) + 0.043 ( 𝑘𝑘𝑘𝑘
𝐵𝐵𝐵𝐵
) ATh ( ) + 0.0417 (
) ARa ( ) + 1.1 (
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
𝑘𝑘𝑘𝑘
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
𝐵𝐵𝐵𝐵
𝑘𝑘𝑘𝑘
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
) ARa ( ) + 0.599 ( 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
𝐵𝐵𝐵𝐵
ℎ 𝐵𝐵𝐵𝐵
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
𝐵𝐵𝐵𝐵
(6)
𝐵𝐵𝐵𝐵
(7)
𝑘𝑘𝑘𝑘
) AK ( )
) ATh ( ) + 0.081 ( 𝑘𝑘𝑘𝑘
𝐵𝐵𝐵𝐵
) AK ( ) 𝑘𝑘𝑘𝑘
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
) ATh ( ) + 0.0417 ( 𝑘𝑘𝑘𝑘
𝐵𝐵𝐵𝐵
) AK ( ) 𝑘𝑘𝑘𝑘
𝑛𝑛𝑛𝑛𝑛𝑛 𝑘𝑘𝑘𝑘
ℎ 𝐵𝐵𝐵𝐵
(8) 𝐵𝐵𝐵𝐵
) AK ( ) (9) 𝑘𝑘𝑘𝑘
3.3. Indoor and Outdoor External Annual Effective Doses The annual effective dose is the summation of the dose from external exposure and committed dose by means of both inhalation and ingestion throughout the year according to UNSCEAR Annex B report in 2016 [20]. Depending on indoor and outdoor time spent, the %20 and %80 ratios will be applied in the calculations as put in equations 8 and 9. As far as the definition states, 8760s is the amount of time in 1 year as another conversion factor. Finally, the unit conversion from Gy to Sievert (Sv) was done with 0.7 (Sv/Gy) coefficient decided in UNSCEAR reports. The Sievert has normally the weighting factor in it to differ the radiation dose depending on the radiation type and the effected live tissue. Thus, it is more relevant to a biological effect of ionizing radiation. Also, it is used to assess how much risk the radiation possesses to living organisms in terms of cancer and genetic damage. According to UNSCEAR report in 2000 [17], the world’s average for indoor and outdoor external annual effective dose (AED) were respectively 410 μSv/y and 70 μSv/y. As shown in table 4, average values for both soil and stone were below the allowed value of world’ average.
AEDindoor−external (
μSv y
AEDoutdoor−external (
) = Dindoor (
μSv y
nGy h
) = Doutdoor (
) × 8760 (h) ×
nGy h
80
100
) × 8760 (h) ×
Sv
× 0.7 ( ) × 103
20
100
Gy
Sv
× 0.7 ( ) × 103 Gy
(10)
(11)
3.4. Excess Lifetime Cancer Risks As the formulas 12 and 13 indicates, life expectancy (LE) and risk factor (RF) are the common parts of the equations. Life expectancy of a country might change from country to country in various reasons. However, LE was taken as at least 78 for people with healthy life style in Turkey. Risk factor was given as 0.05 by ICRP publication 60
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131 7
[8]. In addition, world average for indoor and outdoor ELCR was indicated as 2840 μSv and 370 μSv by Qureshi et al, 2014 [13]. When table 4 was checked, all values for soil and stone were below this average value. ELCR indoor (μSv) = AEDindoor−external (
μSv y
ELCR outdoor (μSv) = AEDoutdoor−external (
(12)
) × LE × RF
μSv y
(13)
) × LE × RF
Table 3. Soil Sample No
Doutdoor_external a (nGy/h)
Doutdoor_externalb
Doutdoor_externalc
Dindoor_externalc
(nGy/h)
(nGy/h)
35.70 43.76 48.44 44.87 50.12 31.09 52.10 31.95 26.71 67.26 27.04
70.39 84.79 96.68 86.84 100.58 62.19 103.00 64.01 51.83 130.04 53.27
41.73
82.15
59
84
1 2 3 4 5 6 7 8 9 10 11
36.93 46.03 49.76 47.23 51.22 31.81 53.94 32.74 27.93 70.80 27.97
(nGy/h) 36.57 44.62 50.04 45.73 51.88 32.06 53.61 33.08 27.11 68.45 27.65
Mean
43.31
42.80
World Average
59
59
31.05 25.26 52.82 31.46 19.63 64.16 19.89
30.65 25.72 51.87 30.89 20.48 62.84 19.90
30.06 24.91 50.77 30.29 19.62 61.70 19.51
59.14 50.21 99.44 59.33 40.29 120.62 38.80
34.90
34.62
33.84
66.83
Stone Sample No 1 2 3 4 5 6 7 Mean
Formulas are used as in these references: a UNSCEAR 1988 [15], b UNSCEAR 2000 [17]; UNSCEAR ANNEX B 2008 [19], c Beretka & Mathew 1985 [3]; Qureshi, 2014 [13]. World average is regarded as the same for both soil and stone.
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Table 4.
Soil Sample No 1 2 3 4 5 6 7 8 9 10 11 Mean W. A. Stone Sample No 1 2 13 4 5 6 7 Mean
AEDindoor_external a,b
AEDoutdoor_externala,b AEDoutdoor_externala,b,c
ELCRindoorb,d
ELCRoutdoorb,d
(μSv/y) 345.30 415.96 474.28 426.00 493.43 305.09 505.27 313.99 254.27 637.93 261.31 402.98 410
(μSv/y) 45.30 56.45 61.02 57.93 62.82 39.01 66.15 40.16 34.25 86.83 34.30 53.11 70
(μSv/y) 43.78 53.67 59.41 55.03 61.46 38.13 63.89 39.19 32.76 82.49 33.17 51.18 70
(μSv) 1346.66 1622.26 1849.69 1661.41 1924.38 1189.86 1970.54 1224.56 991.65 2487.93 1019.11 1571.64 2840b
(μSv) 170.76 209.32 231.69 214.61 239.70 148.73 249.18 152.83 127.76 321.71 129.35 199.60 370b
Stone Sample
Stone Sample
Stone Sample
Stone Sample
Stone Sample
249.01 290.12 246.32 487.81 291.04 197.64 591.73 190.33 327.85
38.08 30.98 64.78 38.59 24.08 78.68 24.40 42.80
36.86 30.55 62.26 37.15 24.07 75.67 23.92 41.50
1131.47 960.64 1902.46 1135.05 770.78 2307.75 742.28 1278.63
143.76 119.14 242.82 144.88 93.85 295.11 93.30 161.84
Formulas are used as in these references: a UNSCEAR (2000) [17], bQuereshi (2014) [13], cUNSCEAR (1988) [15], d ICRP (1991) [8]. For the column 2, the Doutdoor_external values are calculated with equation in UNSCEAR report in 1988 [15]. W.A. stands for world average stated by UNSCEAR report in 2000 [17].
3.5. Gross Alpha and Beta Activity in water According to guidelines for drinking water quality report published by WHO in 2011 [22], the most common approach was to look at the residue activity after evaporating known value of a water sample. That was all done for our samples by CNAEM. The health safety procedure stated in the same report was that no further action was necessary if gross alpha activity was either lesser than 0.5 Bq/L or equal to 0.5 Bq/L. On the other hand, same was valid if the gross beta activity was either lesser than 1 Bq/L or equal to 1 Bq/L. On the contrary, it was necessary to determine individual radionuclide concentrations and to compare with guidance levels if gross alpha activity is higher than 0.5 Bq/L and gross beta activity is higher than 1Bq/L. Then, water would be regarded as suitable for use if dose
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is lesser than 0.1mSv or equal to it. Otherwise, it should be considered to take remedial action to reduce the dose. When all these perspectives were considered, the results in table 5 was below the maximum level of health risk. Table 5. Water Sample Dagbası Baglar WHOa
Total α activity concentration (Bq/L)
MDA
0.02±0.01 0.03±0.01 Max 0.5
0.01 0.01
Total β activity concentration (Bq/L) 0.06±0.02 0.22±0.03 Max 1
MDA 0.02 0.02
Dagbası and Baglar are the names of neighborhoods of Siverek town of Sanlıurfa province. aWHO refers to the report published in 2011 [22] under the title of “Guidelines for drinking water quality, 3rd Edition”.
4. Conclusion In the current study, widely used NaI(Tl) detector was employed for gamma-ray spectrometry. The purpose was to detect some NORM in soil, stone and water samples in Siverek region in Sanlıurfa, Turkey. Thus, 11 soil, 7 stone and 2 water samples were analysed through their decay rates to give us more meaningful data in human health perspective. Various published articles and reports were scanned to get the precise world widely accepted information. For the current data, focus was on 214Bi for 238U activity, 208Tl for 232Th activity and another activity for widely encountered radionuclide of 40K. In summary, average measurements of all 11 and 7 samples from soil and stone were under the world average activities as shown in table 1. In addition, gross alpha and beta activities for water samples were checked to be within the allowed values of 0.5 Bq/L and 1 Bq/L as stated by WHO. To evaluate the radiological impact of these samples, distinct units of activities were calculated to compare with world’s standards. Among them, Raequivalent activity, Hinternal and Hexternal indices, indoor and outdoor absorbed dose rates, indoor and outdoor external AED, indoor and outdoor ELCR levels can be listed. In summary, most of the data points and all average measurement outcomes turned out to be inside the allowed values given by organizations like WHO, UNSCEAR, ICRP even though some of the individual parameters showed slightly over the world average desired values. Acknowledgements I’d like to thank former master student Mehmet Altıntas in Harran University for data collection and processing steps. References [1] Altıntas, M. (2018). Determination of natural radioactivity concentrations in Siverek town soil, water and stone samples. (Unpublished master’s thesis). Harran University, Sanliurfa, Turkey. [2] Apaydın, G. , Köksal, O. K. , Cengiz, E. , Tırasoğlu, E. , Baltaş, H. , Karabulut, K., et al. (2019). Assessment of natural radioactivity and radiological risk of sediment samples in Karacaören II dam Lake, Isparta/Turkey. ALKÜ Fen Bilimleri Dergisi, 28-35. Retrieved from http://dergipark.gov.tr/alku/issue/41490/492920. [3] Beretka,J.&Mathew, P.J. (1985). Natural radioactivity of Australian building materials, industrial wastes and by-products. Health Phys. 48, 87. [4] Diehl, J. (2004). Handbook of radioactivity analysis. 2. Aufl., Herausgegeben von Michael F. L'Annunziata. Angewandte Chemie, 116(13), pp.1647-1647. [5] Eke, C. (2017). Determination of activity concentrations of natural and artificial radionuclides in some commercial salt samples. Sakarya University Journal of Science, 21 (6), 1422-1433. DOI: 10.16984/saufenbilder.305792. [6] Gezer, F., Turhan, Ş., Uğur, F., Gören, E., Kurt, M. & Ufuktepe, Y. (2012). Natural radionuclide content of disposed phosphogypsum as TENORM produced from phosphorus fertilizer industry in Turkey. Annals of
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Nuclear Energy, 50, 33-37. [7] Gilmore, G. R. (2008). Practical Gamma-ray Spectrometry, 2nd Edition. Chichester, West Sussex, England: John Wiley & Sons (Eds.). ISBN: 978-0-470-86196-7. [8] ICRP, 1991. 1990 Recommendations of the International Commission on Radiological Protection. ICRP Publication 60. Ann. ICRP 21 (1-3). [9] Ilker Can Celik. (2014). A particle-𝛾𝛾 coincidence study of 26Na using the transfer reaction 25Na(d,p γ)26Na. (Doctoral thesis, University of Surrey). Retrieved from personal.ph.surrey.ac.uk/~phs1wc/report/CelikPhD-Thesis-2014.pdf. [10] Krieger, R. (1981) Radioactivity of Construction Materials. Betonwerk und Fertigteil-Technik/Concrete Precasting Plant and Technology, 47, 468-446. [11] Nyanda, P.B. & Nkuba, L. L. (2017) Natural radioactivity in vegetables from selected areas of Manyoni District in Central Tanzania. Physical Science International Journal, 16 (2), 4. [12] OECD Nuclear Energy Agency. (1979, May). Exposure to radiation from the natural radioactivity in building materials. Nuclear Energy Agency Organisation for Economic Co-operation and Development. [13] Qureshi, A. A., Tariq, S., Din, K.U., Manzoor, S., Calligaris, C. & Waheed, A. (2014). Evaluation of excessive lifetime cancer risk due to natural radioactivity in the river’s sediments of Northern Pakistan. Journal of Radiation Research and Applied Sciences, Volume 7, Issue 4. Pages 438-447. [14] UNSCEAR. (1982). Ionizing Radiation: Sources and Biological Effects. United Nations Scientific Committee on the Effect of Atomic Radiation 1982 Report to General Assembly, with Annexes. United Nations, New York. [15] UNSCEAR. (1988). Sources, Effects and Risks of Ionizing Radiation. United Nations Committee on the Effects of Atomic Radiation 1988 Report to General Assembly, with Annexes. United Nations, New York. [16] UNSCEAR. (1993). United Nations Scientific Committee on the Effects of Atomic Radiation. Sources, Effects and Risks of Ionizing Radiation. Report to the General Assembly with Scientific Annexes, United Nations, New York, 183-184. [17] UNSCEAR. (2000). United Nations Scientific Committee on the Effect of Atomic Radiation, Radiation sources and Effects of ionizing radiation. Report to General Assembly, with Scientific Annexes. United Nations, New York. [18] UNSCEAR (2000) Annex B: Exposure from Natural Radiation Sources. Report to General Assembly, United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), New York. [19] UNSCEAR. (2008). Sources and Effects of Ionizing Radiation. United Nations Committee on the Effects of Atomic Radiation. Report to General Assembly with Annexes. Volume 1, Annex B, Exposures of the public and workers from various sources of radiation. United Nations, New York. [20] UNSCEAR. (2016). Sources, Effects and Risks of Ionizing Radiation. United Nations Committee on the Effects of Atomic Radiation. Report to General Assembly with Annexes. Scientific Annex B, Radiation Exposures from Electricity Generation. United Nations, New York. [21] Yıldız, N., Oto, B. , Turhan, Ş., Uğur, F.A., Gören, E. (2014). Radionuclide determination and radioactivity evaluation of surface soil samples collected along the Erçek Lake basin in eastern Anatolia, Turkey. Journal of Geochemical Exploration, 146, 36. [22] World Health Organization. (2011). Guidelines for drinking-water quality, 4th ed. Geneva: World Health Organization