CODEN (USA): IJCRGG, ISSN: 0974-4290, ISSN(Online):2455-9555 Vol.10 No.7, pp 658-662, 2017
Abstract : The rate of alpha emission from teeth in Najafcity was measured using a nuclear track detector CR-39 to determine the level of environmental contamination by radionuclides that alpha-emitting. The results were showed that the highest emission of alpha was (0.2364) mBq cm-2in Najaf / Hey Al-Meladwhile the lowest emission was (0.0017)mBq cm-2in Najaf / Hey Al-Wafaa.The mean of alpha emission was (0.0461±0.0046) mBq cm-2 , Which indicate no environmental contamination by radionuclide's which emitting alpha particles compared with the previous studies. Key Words : Alpha, Teeth, CR-39, Natural Radioactivity, Najaf.
1. Introduction
Alpha particles emitted by decay of radionuclides such as uranium and radium which enter the human body by inhalation or ingestion, these particles are more damaged for human tissue1, when alpha emitters enter the body through the digestive system and breathe move to the others organs by blood2, to be deposited in bone then in teeth, as an extension of the skeleton3. Teeth according to many studies is a good indicator for natural exposure to radiation4.
2. Material and Methodology
Nuclear track detector with a chemical form C12H18O7, most important qualities are transparent, colorless5, the techniques of nuclear impact detectors in the identification of the effects of radioactive materials where this effect in the form of narrow paths are generated when the passage of radiation and formed a hidden effects6 .
Thirty-nine samples of teeth were collected from people in specialist center of dentistry in Najafat different regions from southern and northern regions in Najaf city.
2.3Preparation of samples:
Put all samples in formaldehyde solution until complete samples collection. Samples were taken to the laboratory for cutting each tooth into two halves longitudinally by engine machine and then placed in the oven for drying. As shown in Fig.(1)
Fig.(1): Samples in Oven
After each tooth has been cut into two halves, it is placed in contact with the detector in the form of sandwich. And left for 132 day during which time the emission of alpha particles from the sample to the detector to form the hidden effect, which is detected by the process of chemical etching. As shown in Fig.(2)
Fig.(2) : Natural Exposure Method
All CR-39 Detectors were etched in 6.25 N NaOH solution in 70±1 C⁰ for 6 hours. The solution is heated by a water bath after being placed in a conical flask tightly closed to prevent evaporation of the solution during the process of etching and change its concentration. After finishing the etching process, remove the detectors from the solution by tweezers and wash with distilled water and then dry.
3. Calculation
The track density of each detector was calculated by seeing the effects by the optical microscope with magnification of 10X after connecting it to the PC and by the equation (1)7
౹
ಖ (1)
౧
where; ρ= Track density Navg = average of total pits A= area of field view The CR-39 detector efficiency was also calculated from the equation (2)8
౼ౠ
ಊ | ఠ | ౼ | (2) | |
-1 |
where VB = bulk etch rate (µm h)
VT = track etch rate (µm h-1) finally, Was calculated alpha emission rate in mBq cm-2, by using equation (3)8
೬್
ವ ಊ(3)
౺
whereρs= number of tracks in sample ρb= number of tracks in background detector T= Period of exposure=132 d
4. Results and Discussion
After the alpha emission rate was calculated for all the studied samples, it was found that the highest
-2 -2
emission of alpha was (0.2364) mBq cmwhile the lowest emission of alpha was (0.0017) mBq cm. Fig.(3) shown the highest and lowest track density.
Figure(3): Highest and Lowest of Alpha Emission Rate
Generally, the mean of alpha emission rate in Najaf city was (0.0466±0.0076) mBq cm-2.Table (1) represented alpha emission rate in teeth samples. Also the results shown that alpha emission rate in northern regions (0.0467±0.0103) was higher than insouthern regions (0.0459±0.0103) . Fig.(4) shown alpha emission rate in northern and southern regions in Najaf city .
Table (1): Alpha Emission Rate in Teeth Samples Fig.(4): Alpha Emission Rate in Northern and Southern Regions in Najaf City
No. | Sample code | Location | Eα (mBq cm -2 ) |
1 | CR-250 | Northern regions/ Hey Al-Melad | 0.1015 |
2 | CR-164 | Northern regions/ Hey Al-Jemaeya | 0.0258 |
3 | CR-365 | Northern regions/ Hey Al-Neser | 0.0122 |
4 | CR-221 | Northern regions/ Hey Al-Neser | 0.0465 |
5 | CR-223 | Northern regions/ Hey Al-Jemaeya | 0.0264 |
6 | CR-388 | Northern regions/ Hey Al-Melad | 0.1164 |
7 | CR-336 | Northern regions/ Hey Al-Rahma | 0.0324 |
8 | CR-224 | Northern regions/ Hey Al-Rahma | 0.0149 |
9 | CR-317 | Northern regions/ Hey Al-Jazera | 0.0138 |
10 | CR-220 | Northern regions/ Hey Al-Jazera | 0.0445 |
11 | CR-200 | Northern regions/ Hey Al-Wafaa | 0.0049 |
12 | CR-148 | Northern regions/ Hey Al-Wafaa | 0.0016 |
13 | CR-170 | Northern regions/ Hey Al-Aladala | 0.0337 |
14 | CR-417 | Northern regions/ Hey Al-Furat | 0.0536 |
15 | CR-198 | Northern regions/ Hey Al-Jemaeya | 0.0333 |
16 | CR-314 | Northern regions/ Hey Al-Muhandsen | 0.0931 |
17 | CR-278 | Northern regions/ Hey Al-Melad | 0.2364 |
18 | CR-222 | Northern regions/ Hey Al-Melad | 0.0451 |
19 | CR-269 | Northern regions/ Hey Al-Askary | 0.0050 |
20 | CR-415 | Northern regions/ Hey Al-Macramé | 0.0211 |
21 | CR-311 | Northern regions/ Hey Al-Macramé | 0.0867 |
22 | CR-151 | Northern regions/ Hey Al-Nidaa | 0.0083 |
23 | CR-247 | Northern regions/ Hey Al-Nidaa | 0.0609 |
24 | CR-149 | Northern regions/ Hey Al-Neser | 0.0037 |
25 | CR-169 | Northern regions/ Hey Al-Neser | 0.0453 |
26 | CR-312 | Southern regions/ Street city | 0.0473 |
27 | CR-338 | Southern regions/ Al-Hera | 0.0388 |
28 | CR-218 | Southern regions/ Hey Al-Zahraa | 0.0053 |
29 | CR-418 | Southern regions/ Hey Al-Qadiseya | 0.0874 |
30 | CR-166 | Southern regions/ Hey Al-Ansar | 0.1201 |
31 | CR-173 | Southern regions/ Hey Al-Quds | 0.0043 |
32 | CR-145 | Southern regions/ Hey Al-Ansar | 0.1206 |
33 | CR-337 | Southern regions/ Hey Al-Quds | 0.0544 |
34 | CR-225 | Southern regions/ Street city | 0.0153 |
35 | CR-199 | Southern regions/ Hey Al-Emammahde | 0.0066 |
36 | CR-274 | Southern regions / Hey Ansar | 0.0450 |
37 | CR-195 | Southern regions / Hey Ansar | 0.0276 |
38 | CR-196 | Southern regions / Hey Ansar | 0.0410 |
39 | CR-191 | Southern regions / Hey Ansar | 0.0294 |
5. Conclusions
The data showed that:
6.Acknowledgement
The authors would like to thank a Dt. Tholfqarmajedhassen /Babylon dental lab. for helping me in a preparation the teeth samples. Also many thanks go to Dr.AhmedJawadAlimam/specialist center of dentistry in najaf department of oral & maxillofacial surgery.
References
*****