Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Subscribe Contacts Login 
Home Print this page Email this page Small font size Default font size Increase font size Users Online: 53


 
 Table of Contents 
ORIGINAL ARTICLE
Year : 2015  |  Volume : 38  |  Issue : 1  |  Page : 35-38  

Natural radioactivity concentrations in some medicinal plants and annual committed effective dose from their consumption


Department of Physics, Faculty of Science, South Valley University, 83523 Qena, Egypt

Date of Web Publication14-Aug-2015

Correspondence Address:
Shaban Ramadan Mohamed Harb
Department of Physics, Faculty of Science, South Valley University, 83523 Qena
Egypt
Login to access the Email id

Source of Support: Nil., Conflict of Interest: None


DOI: 10.4103/0972-0464.162816

Rights and Permissions
  Abstract 

Natural radioactive substances may be present in the environmental substances that have uses in pharmacy and medicine as health supplements. This paper presents natural radioactivity levels in some of the medicinal plants available in Egypt. Natural radionuclides such as 226Ra, 228Ra, and 40K were measured in medicinal plants samples collected from the local market in Qena, Upper Egypt. All measurements were performed with a gamma spectrometry with high-purity germanium detector. The radioactivity concentration ranged from 0.4 ± 0.2 to 21.0 ± 1.2 Bq/kg for 226Ra, from <0.3 to 42.3 ± 5.9 Bq/kg for 228Ra, and from 140 ± 6 Bq/kg to 1538 ± 54 Bq/kg for 40K. The total annual committed effective doses ranged from 0.003 to 0.073 mSvy−1 with an average value of 0.02 mSva−1

Keywords: Medicinal plants, environmental radioactivity, high-purity germanium detector, committed effective dose


How to cite this article:
Harb SR. Natural radioactivity concentrations in some medicinal plants and annual committed effective dose from their consumption. Radiat Prot Environ 2015;38:35-8

How to cite this URL:
Harb SR. Natural radioactivity concentrations in some medicinal plants and annual committed effective dose from their consumption. Radiat Prot Environ [serial online] 2015 [cited 2019 Sep 15];38:35-8. Available from: http://www.rpe.org.in/text.asp?2015/38/1/35/162816


  Introduction Top


From the dawn of human history, a lot of plants were used as nutrients and in medicine. The study of the radioactivity concentration in plants in the environment are of interest within ecological and plant evolution under certain conditions of geochemical point of view and adaptation, and it thus provide information in the monitoring of environmental radioactivity.[1],[2] Radionuclides and their decay products from 238U and 232Th series together with 40K are terrestrial primordial radionuclides, which originated from the earth's crust and are the sources of natural radioactivity in the environment.[3]

The World Health Organization define traditional medicine as comprising therapeutic practices that have been in existence, often for hundreds of years, before the development and spread of modern medicine and are still in use today.[4]

The aim of this work was to study the natural radioactivity concentration in selected medicinal plants used in Qena, Egypt. In fact, the presence of radionuclides in these constitutes a pathway of their migration to the human, via the food chain or drinking. There are several sources that contribute to plants contamination such as direct deposition on surface, deposition on soil, root uptake, and transfer to leaves, barks, seeds, flowers, fruits, and berries.[5]


  Experimental Methods Top


Sampling and processing

Medicinal plants used in this work were obtained from the local market at Qena, Upper Egypt, and are listed in [Table 1]. The medicinal plant samples were washed with normal water, as for human consumption, weighed, and divided into small parts, dried in a stove at a temperature of 80°C for 48 h, ground into powder,[6] and then filled in 250 mL polypropylene bottles. They were sealed and left for at least 4 weeks before counting by gamma spectrometry in order to ensure that radioactive secular equilibrium.[7]
Table 1: Activity concentration of 226Ra, 228Ra, and 40K (in Bqkg−1) and annual committed effective dose (mSva−1) in the medicinal plant samples (dry weight)

Click here to view


Direct determination of radionuclides in medicinal plant samples without any chemical treatment was performed at the Institute for Radioecology and Radiation Protection, Hanover University, Germany, using a p-type high-purity germanium coaxial detector (GEM 50198-P) of 35% relative efficiency, with a resolution of 1.78 keV at 1.332 MeV. It is shielded with 10 cm lead and 2 mm copper, and coupled to an 8192-channel analyzer.[8] The counting efficiencies of the γ-ray peaks were measured using QCY48 standard solutions (Physikalisch-Technische Bundesanstalt, Germany) and were determined using a certified standard solution containing57 Co,60 Co,85 Sr,88 Y, 109Cd, 113Sn, 139Ce, 137Cs, and 241Am. The geometry of the experimental samples was the same as that of the standard samples [Figure 1].[9]
Figure 1: Location of medicinal plant in Qena governorate, Egypt

Click here to view


Measurements and calculation

Calculation of radionuclides and annual committed effective dose

Following the spectrum analysis, counting rates for each detected photo peak and activity per mass unit for each of the detected nuclides are calculated. The specific activity (in Bq/kg) is given by harb.[10]

Aspecific = (N/tN0/t0)/(Iγ e m) (1)

Where, N is the net counts of a given peak, t = 18 – 24 h is the counting time for the sample. N0 is the background of the given peak, t0= 72 h is the counting time for the background, and ε is the detection efficiency. Iγ is the number of gamma photons per disintegration and m is the mass in kg of the measured sample. If there is more than one peak in the energy analysis range for a nuclide, an average of the peak activities is made, and the result is then the weighted average nuclide activity. Based on the measured γ-ray peaks, emitted by daughter radionuclides in the 232Th and 238U decay series, and 40K, their concentrations were determined. Calculations relied on the establishment of secular equilibrium in the samples, due to the much smaller lifetime of daughter radionuclides in the decay series of 232Th and 238U. The γ-rays of 212Pb (238.63 keV), 208Tl (583.2 keV), and 228Ac (338.4, 911 and 969 keV) were used to determine the 228Ra concentration. The γ-rays of 214Bi (609.3, 1120.3, and 1764.5 keV) and 214Pb (295.2 and 351.9 keV), for 226Ra. The 1461 keV gamma of 40 k was used to determine the concentration of 40 k in different samples. The total uncertainty[11] value is composed of the random and systematic errors in all the factors involved in producing the final nuclide concentration result listed in [Table 1].

Having obtained the values for the specific activity concentrations of the individual naturally occurring radionuclides in the medicinal plants, the average annual committed effective dose, Eave, for ingestion of naturally occurring radioactive materials (NORMs) in the medicinal plants were calculated using the expression (2) given by Lordford.[2]

Eave = Ip. DCFing. Asp (2)

Where DCFing is the dose conversion factor for ingestion, for each radionuclide (i.e., 2.8 × 10−7 Sv/Bq, 6.7 × 10−7 Sv/Bq, and 6.2 × 10−9 Sv/Bq for 226Ra, 228Ra, and 40K, respectively, for an adult,[2],[12] Ip is the consumption rate from intake of NORMs in medicinal plants, a consumption rate of 1.8 kg/year was assumed for all the medicinal plants used in this study, assuming that a patient needs 100 ml/day of the herbal preparation or product during the treatment period. Moreover, Asp is the activity concentration in the plant sample.


  Results and Discussions Top


[Table 1], [Figure 2] and [Figure 3] show the activity concentrations (Bq/kg) of the natural radionuclides 226Ra, 228Ra, and 40K determined in the medicinal plant selected in this study. All natural radionuclides were determined in 18 medicinal plants samples; the data show its activity concentrations ranged between 0.4 ± 0.2 and 21.0 ± 1.2, <0.3 and 43 ± 6, 140 ± 6 and 1538 ± 54 Bq/kg for 226Ra, 228Ra, and 40K, respectively. All samples showed 226Ra, 228Ra, and 40K activity concentrations higher than the minimum detectable activity. The highest activity concentration was found in the results of nees, for 226Ra, sweet laurel for 226Ra, 228Ra, and 40K.
Figure 2: The variation of the activity concentrations of 226Ra, and 228Ra, in the different kinds of medicinal plant

Click here to view
Figure 3: The variation of the activity concentrations of 40K in the different kinds of medicinal plant average annual committed effective dose in the medicinal plants

Click here to view


The variations in the activity concentrations could be due to differences in the geological location of the plants and the radiochemical composition of the soils in which these medicinal plants are grown or cultivated since the levels of activity concentration of natural radionuclides are not normalized across the globe and the plants ability to absorb particular elements more than the others.[2]

From [Table 1] and [Figure 4] we can see that the average annual committed effective doses due to the ingestion of 226Ra, 228Ra, and 40K in the medicinal plant. The total annual committed effective doses of 226Ra, 228Ra, and 40K varied from 0.003 to 0.07 mSvy−1 with an average value of 0.02 mSvy−1. The highest average was recorded for sweet laurel and tamarind has the lowest. [Figure 4] shows the average annual committed effective dose due to radionuclides in the medicinal plant samples. However, the calculated average annual effective dose to any individual in the population group due to the ingestion of natural radionuclides in the medicinal plants is far below the average radiation dose of 0.3 mSvy−1 received per person worldwide.[12]
Figure 4: The variation of the annual committed effective dose from natural radionuclides ( 226Ra, 228Ra, and 40K) in the medicinal plant samples

Click here to view



  Conclusions Top


Natural radionuclides such as 226Ra, 228Ra, and 40K were measured in medicinal plants collected from the local markets in Qena, Upper Egypt. The radioactivity concentration ranged from 0.4 ± 0.2 to 21.0 ± 1.2 Bq/kg for 226Ra, from <0.3 to 42.3 ± 5.9 Bq/kg for 228Ra, and from 140 ± 6 Bq/kg to 1538 ± 54 Bq/kg for 40K. The total annual committed effective doses ranged from 0.003 to 0.073 mSvy−1 with an average value of 0.02 mSv.


  Acknowledgments Top


The author thank Prof. C. Walther, Director of Institute for Radioecology and Radiation Protection (IRS), Hannover University, Germany, for his encouragement and support.



 
  References Top

1.
Mukhammedov S, Tillaeva K. Natural Radioactivity of some medicinal plants. J Nucl Radiat Phys 2005;1:73-6.  Back to cited text no. 1
    
2.
Tettey-Larbi L, Darko EO, Schandorf C, Appiah AA. Natural radioactivity levels of some medicinal plants commonly used in Ghana. Springerplus 2013;2:157.  Back to cited text no. 2
    
3.
Kessaratikoon P, Awaekechi S. Natural radioactivity measurement in soil samples collected from municipal area of Hat Yai district in Songkhla province, Thailand. KMITL Sci J Sect A 2008;8:52-58.  Back to cited text no. 3
    
4.
WHO. Progress Report by the Director General, Document No. A44/20, 22. Geneva: World Health Organisation; 1991.  Back to cited text no. 4
    
5.
Desideri D, Meli MA, Roselli C. Natural and artificial radioactivity determination of some medicinal plants. J Environ Radioact 2010;101:751-6.  Back to cited text no. 5
    
6.
Yu KN, Mao SY. Assessment of radionuclide contents in food in Hong Kong. Health Phys 1999;77:686-96.  Back to cited text no. 6
    
7.
Changizi V, Jafarpoor Z, Naseri M. Measurement of 226Ra, 228Ra,13 7Cs and 40K in edible parts of two types of leafy vegetables cultivated in Tehran province-Iran and resultant annual ingestion radiation dose. Iran J Radiat Res 2010;8:103-10.  Back to cited text no. 7
    
8.
Harb S, Michel R. Uptake of U- and Th-series radionuclides by cereal crops in Upper Egypt. Nucl Sci Tech 2009;20:99-105.  Back to cited text no. 8
    
9.
Harb S, Salahel Din K, Abbady A. Efficiency Calibrations of HPGe Detectors for Gamma Spectrometry Levels of Environmental Samples. 3rd Environmental Physics Conference. Aswan. Egypt; 19-23 February, 2008.  Back to cited text no. 9
    
10.
Harb S, El-Kamel AH, Abd El-Mageed AI, Abbady A, Rashed W. Radioactivity levels and Soil-to-plant transfer factor of natural radionuclides from Protectorate area in Aswan, Egypt, World J Nucl Sci Technol 2014;4:7-15.  Back to cited text no. 10
    
11.
International Standards Organization (ISO/IEC 17025:1999). European Committee for Standardization, Brussels; 1999.  Back to cited text no. 11
    
12.
WHO guidelines for assessing quality of herbal medicines with reference to contaminants and residues. Spain; 2007.  Back to cited text no. 12
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]
 
 
    Tables

  [Table 1]



 

Top
   
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

 
  In this article
Abstract
Introduction
Experimental Methods
Results and Disc...
Conclusions
Acknowledgments
References
Article Figures
Article Tables

 Article Access Statistics
    Viewed1325    
    Printed6    
    Emailed0    
    PDF Downloaded237    
    Comments [Add]    

Recommend this journal