O R I G I N A L A R T I C L E
A study of gross alpha and beta measurements for thermal springs
in Central Anatolia, Turkey
Mihriban S¸ahin1•Mehmet Emin Korkmaz2•Osman Agar2• Abdullah Dirican1
Received: 28 July 2016 / Accepted: 25 January 2017 / Published online: 2 February 2017 Ó Springer-Verlag Berlin Heidelberg 2017
Abstract A screening of natural radioactivity content has been carried out in thermal water samples collected from surrounding of Central Anatolia, Turkey. The concentra-tion levels of gross alpha and beta of 19 different samples has been determined using the low background gas-flow proportional counter. The measured gross alpha and beta activities in waters range from 0.11 to 16 Bq/L and 0.10 to 16.9 Bq/L, respectively. The measured values of gross alpha and beta concentrations are compared to previous studies in the literature and recommend WHO guideline activity concentration. The data resulting from the mea-surement have been statistically analyzed.
Keywords Thermal water Gross alpha Gross beta Radioactivity
Introduction
There are many thermal springs which originate from dif-ferent geological layers by drilling in spas (sanus per aquam) in Turkey, especially in Center Anatolian region. Thermal springs attract a growing interest from researcher in terms of human health, ecology and the environmental protection. In addition, the spas have been becoming increasingly popular because of both notable historic and cultural importance and the practice of using springs for
medical purposes (Rodenas et al.2008; Acar et al. 2013). At present, about thirty of such centers are functioning in studied area and thermal ground waters of the spas are regularly consumed by thousands of people to drink and take baths every year. These waters may contain natural radioactivity connected to both gross alpha and beta radi-ation at high levels. It is probably mainly caused by238U, 234U, 230Th, 226Ra, 210Po, 232Th and 228Th for the alpha particle activity. 210Pb and 228Ra as well as 40K can be expected to be the major sources of the beta particle activity (Bonotto et al.2009). That is why these waters can lead to radiation protection problems for workers and consumers. Protection of public against natural radioac-tivity is not regulated and exposure from thermal springs is not treated in detail in Turkey. Consequently the quality of thermal spring waters should be strictly recorded and controlled. At the same time, more detailed study is nec-essary for precise dose estimation. Taking into account requirements such as social, economic, political technical and cultural, quality standards of water are established by different countries to meet their national priorities (Damla et al.2009).
Because of these facts, as the first attempt of the radi-ological suitability for different types of waters, analyses of gross alpha and beta activities are widely employed (Wallova et al.2016; Calin et al.2015; Turhan et al.2013; Pakkong et al. 2013). This analytical technique has the major advantages, e.g., the relatively stability, low costs and simplicity. Therefore, it makes it possible to monitor waters under investigation for relative radioactivity levels there on (Jobba´gy et al.2011). According to World Health Organization(WHO) report, the recommended interna-tional permissible values are 0.5 Bq/L for gross alpha activity and 1 Bq/L for beta activity in waters, respectively (WHO2011).
& Osman Agar
osmanagar@kmu.edu.tr
1 Saraykoy Nuclear Research and Training Center, TAEK,
06983 Kazan, Ankara, Turkey
2 Department of Physics, Karamanoglu Mehmetbey
University, Karaman, Turkey DOI 10.1007/s12665-017-6445-8
The present investigation demonstrates the radioactivity levels of gross alpha and gross beta resulting from mea-surement in thermal spring waters used as spas in Central Anatolian region, Turkey.
Materials and methods
Sample collection and preparation
The thermal spring waters were collected from 19 different sampling points in Central Anatolian region in order to determine radioactivity in these waters. The locations of sample points are shown in Fig.1. The linear polypropylene bottles of 5 L capacity were carefully washed using Radi-acwash in the laboratory, and the water samples were col-lected in these bottles. After the sampling, the thermal water samples were transported to the laboratory for analysis.
In order to protect public health, preparation of water standards has performed according to US Environmental Protection Agency (EPA; Krieger1976). In this work, the method, called as EPA-900, was carried out for the mea-surements of gross alpha and gross beta activities in the thermal spring waters. To avoid adsorption and precipita-tion of radioactive materials in the sample on the wall of the bottles and to prevent adsorption of radionuclides onto the dissolved organic particulates, 1 M nitric acid (HNO3) is added to the collected water samples until the pH of the solution equals to 2. All samples then were stored for a 16-h period before beginning the sample preparation pro-cess. After that, some of the water sample was transferred
to a clean beaker and evaporated under the infrared lamp up to an amount of 20–30 mL remaining. Remaining sample was put on a planchet with a diameter of approxi-mately 5 cm and dried under the IR lamp again. Thereafter, to gain constant weight, the last residue was kept in a drying oven at 105 ± 2°C for 2 h. The important point in this step is to get the residue on planchet with minimum self-absorption. For calibration, the residue is generally described as amount of 5 mg cm-1. The residue amount varies according to the quality and type of water. There-fore, the sample of 50 mL is put into a beaker at the beginning and the residue amount is determined. If the desired residue amount is reached, the process goes on with the radiation measurement of the sample. In case of determining not desired amount of residue, the volume of the sample put into beaker for the evaporation is changed and the steps until residue weighting are repeated. Analytical methods
Gross alpha and beta measurements of the water samples were performed with a low background multi-detector alpha/beta counting system including gas-flow proportional counters of model PIC-MPC 9604. Each apparatus on the detector consists of 4 completely independent sample detectors, a guard detector and lead shielding used to minimize background radiation. The counting time was set to 54.000 s for both gross alpha and beta activities. The gas used in the proportional counter (P-10) has a mixture of 10% methane and 90% argon. The operating voltage of the detector was selected as 1485 V.
The minimum detectable activities (MDAs) are calcu-lated using Eq. (1) (Korkmaz et al.2016a,b):
MDAa;b¼ 2:71 tSCTþ 3:29 ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi cpma;bBKG tSCT þ cpma;bBKG tBCT q Effa;b 100 1 60 VSVol ð1Þ where MDAa,bis minimum detectable value (in Bq/L) for alpha and beta activities, respectively, cpma,b-BKGis alpha and beta background count per minute, Effa,bis efficiency of alpha and beta, VSVolis sample of volume (in L), tSCTis the sample counting time in minute, tBCTis the background counting time in minute and 60 is conversion factor from minute to second. The MDA values for gross alpha and beta are 0.037 and 0.045 Bq/L, respectively.
The calibration was carried out with the help of a cal-cium sulfate nitric solution traced by 90Sr/90Y or 241Am references: Six reference planchets for both alpha and beta measurements were prepared, following the above-men-tioned process and with residue weight changing between 50 and 120 mg. Therefore, this step allows calculating the efficiency for actual samples having different layer thickness.
The background radiation was measured by counting an empty planchet for 54,000 s. The background count rates of the measurement system ranged from 0.04 to 0.08 cpm for alpha, and from 0.4 to 0.9 cpm for beta.
Gross alpha–beta activities of the samples were simply estimated using Eq. (2) (Saleh and Shayeb 2014):
Aa;b¼
N 60Effa;b
100 VS
ð2Þ
where N is separately net gross alpha or net gross beta count rate (cpm), Effa,b is separately gross alpha or beta counting efficiency (in %), VSis volume of sample aliquot (in L) and 60 is conversion factor in this equation.
Results and discussion
Levels of activity concentrations of the gross alpha and beta in 19 water samples together with temperature col-lected from some thermal springs, which are used as spa in Central Anatolian region, are shown in Table1and Fig.2. The obtained data in this study indicate that gross alpha activities of the samples varied between 0.11 ± 0.05 (Konya–2) and 16 ± 0.70 Bq/L (Kırs¸ehir–2), and the gross beta activities changed from 0.10 ± 0.05 (Konya–2) to 16.9 ± 0.50 Bq/L (Kırs¸ehir–2). The gross alpha and beta activities for under investigated samples have average values of 2.07 and 3.07 Bq/L, respectively.
Furthermore, it can be clearly said that the radioactivity levels in the samples markedly changed from point to
point. Table1and Fig.2display that more than half of the thermal spring water samples have the gross alpha and gross beta activity concentrations a few times greater than the upper limit values of 0.5 and 1 Bq/L, respectively, proposed by WHO.
In addition to the results of this study, for comparison Table1 also presents the results of the other studies including the gross alpha and beta activity concentrations of the thermal spring waters in various regions.
The geographical distribution of gross beta/gross alpha activity ratios of the thermal spring waters is shown in Fig.1. Looking at the map, it is hard to say that there is a meaningful distribution from the point of gross beta/gross alpha ratios from region to region. Nevertheless, it may be estimated that in the cities of northern region such as Eskis¸ehir, C¸ ankiri, C¸ orum and partly Ankara, gross beta activities are higher than the gross alpha activities, and in the middle part mostly the gross alpha activities are higher. The remarkable finding is that in Eskis¸ehir and Nig˘de regions gross beta activity is much higher than the gross alpha activity while in Yozgat region the gross alpha activity is much higher than the gross beta region.
The statistical analysis of obtained data for this study also is done using SPSS computer software through mea-surements of gross alpha and beta activity. Figure3shows the form of a frequency distribution for 19 water samples in thermal waters. Information about the statistical analysis data, namely mean values of the arithmetic and geometric, standard deviation, skewness (the degree of deterioration of symmetry), kurtosis coefficient (degree of peakness) and the type of theoretical frequency distribution that best fits each empirical distribution corresponding to the activity levels detected in water samples, is given in Table 2. The kurtosis coefficients of gross alpha and beta concentrations have positive values of 6.46 and 4.94, respectively. For this reason, the frequency distributions have a narrower and higher distribution than Gaussian. Similarly, the skewness calculated as positive values of 2.32 for gross alpha and of 2.08 for beta measurements shows the asymmetric distri-bution having the left tail being shorter than the right as shown in Fig.3.
Conclusions
The main aim of the present investigation is to show radioactivity levels of the gross alpha and beta for thermal spring waters collected from different sites in Central Anatolian region, Turkey. The obtained results for some water samples exceed the guidelines recommend by the WHO for drinking water. The high activity concentrations might be explained by the kind of geological layers and chemical composition. On the basis of the results of this
Table 1 Concentration levels of gross alpha and beta for thermal spring waters
Location Temperature (oC) Gross alpha (Bq/L) Gross beta (Bq/L) References
Spain – LLD–16.95 LLD–60.14 Rodenas et al. (2008) Brazil – 0.002–0.428 0.120–0.860 Bonotto et al. (2009) Batman – 3.9095 2.097 Damla et al. (2009) Samsun – 0.08 0.155 Korkmaz Go¨ru¨r et al. (2011) Emendre – 0.37 0.390 Topcuoglu et al. (2003) Karakaya-Ayas¸ – 0.09 0.25 Acar et al. (2013) I˙c¸mece-Ayas¸ – 2.28 0.47 Acar et al. (2013) Beypazarı – 1.53 1.43 Acar et al. (2013)
Haymana – 2.58 1.82 Acar et al. (2013)
Kızılcahamam – 1.85 2.61 Acar et al. (2013) Eskis¸ehir–1 42 \MDA 0.42 ± 0.07 This study Konya–1 38 0.44 ± 0.07 0.34 ± 0.05 Konya–2 40 0.11 ± 0.05 0.10 ± 0.05 Nig˘de–1 53 \MDA 0.40 ± 0.12 Kırs¸ehir–1 42 1.4 ± 0.14 0.91 ± 0.10 Kırs¸ehir–2 42 16 ± 0.70 16.9 ± 0.50 Nevs¸ehir–1 93 2.3 ± 0.18 1.3 ± 0.10 Kayseri–1 48 0.88 ± 0.18 0.38 ± 0.10 Kayseri–2 38 3.9 ± 0.66 8.3 ± 0.55 Yozgat–1 42 0.64 ± 0.12 \MDA
Sivas–1 37 \MDA \MDA
Sivas–2 43 4.3 ± 0.30 4.1 ± 0.21 C¸ ankiri–1 40 4.1 ± 0.44 7.9 ± 0.36 C¸ orum–1 29 0.13 ± 0.06 0.15 ± 0.06 Ankara–1 53 0.60 ± 0.11 1.8 ± 0.13 Ankara–2 39 0.25 ± 0.04 0.50 ± 0.04 Ankara–3 42 3.8 ± 0.41 3.5 ± 0.28 Ankara–4 41 7.7 ± 0.62 5.8 ± 0.35 Ankara–5 39 6.3 ± 0.56 5.6 ± 0.34 WHO 0.5 1 WHO (2011)
LLD lower limit of detection
0 2 4 6 8 10 12 14 16 18 Concentrations (Bq/L) Location Gross alpha Gross beta Fig. 2 Variation of the gross
alpha and beta activities concentrations versus location
study, it is clear that more detailed investigations for pro-tection of the workers and costumers against high level of radioactivity are necessitated. The data obtained in this paper can provide background information for possible future radiological works in thermal spring waters.
Acknowledgements This study was supported by Karamanoglu Mehmetbey University Scientific Research Project (37-M-16).
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Fig. 3 Histograms of data for gross alpha (left) and beta (right) activities in thermal spring waters
Table 2 Summary statistics for concentrations of gross alpha and beta activity in waters
Statistic data Gross alpha Gross beta Arithmetic mean 2.78 3.07 Geometric mean 1.44 1.07 Arithmetic standard deviation 0.91 0.99
Kurtosis 6.46 4.94
Skewness 2.32 2.08
