الفهرس 
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Abstract
The main target of this study is to make a comparison between
different kinds of fertilizers by measure the concentration of natural
radionuclide’s, heavy metals and toxic substances, using different
techniques.
First, The concentration of the natural radionuclides are measured
in all the studying samples to find the specific radioactivity of 238Useries,
232Th-series and 40K by using a high resolution gamma ray
spectrometer based on coaxial HPGe detector shielded by cylinders of
lead, copper and cadmium. The analysis of data is completed by using
a computerized analyzer fitted with a high multichannel analyzer with
high level software programs.
Fourteen samples of fertilizer were collected from different
places in Egypt markets and industries.
Calculate the radiological parameters (Radium equivalent activity
Raeq, Radiation level index, External hazard index Hex, Internal hazard
index Hin, Absorbed dose rate DR and Effective dose Eeff) to make a
comparison with the permissible international level.
The results of concentration levels are compared with similar
studies carried out in other countries.
The mean activity concentrations of 238U, 232Th, 226Ra and 40K for
studied fertilizer samples has been observed to ranged from (9.67 to
562.10), (11.02 to 362.29), (33.41 to 1162.39) and (92.65 to
17162.88) Bq/Kg for 238U, 232Th , 226Ra and 40K respectively. The permissible activity levels for fertilizers are 50, 50 and 500
Bq/kg for 226Ra, 232Th and 40K respectively as a soil but for super
phosphate (SSP) and potash (PF) fertilizer are 1000, 1000 and 4000
Bq/kg for 226Ra, 232Th and 40K respectively (UNSCEAR, 2000 and
El-Taher & Mohamed Anwar Abdelhalim, 2013).
The concentration values of 226Ra are lower than the permissible
level except samples F2, F5, F10 and F11 but for SSP and PF are
lower than permissible level except F6. The concentration values of
232Th in all studied samples are lower than the permissible level. Also,
the concentration of 40K are lower than permissible level except
samples F1, F3, F10 and F11 but for SSP and PF are lower than
permissible level except F4, F9.
The values of radium equivalent of the samples vary between
(42.54 to 1918.91) Bq/Kg. These values are lower than the
recommended maximum value 370 Bq/Kg (Singh et al., 2005 and
Huy & Luyen, 2006) except (F1, F4, F6, F9 and F10) samples.
The value of radioactivity level index I; vary between (0.34 and
14.22). These values are found to be less than unity except (F1, F3,
F4, F6, F9, F10 and F11) samples.
The value of average external hazard index and average internal
hazard index vary between (0.17 to 5.18) for Hex, (0.26 to 6.44) for
Hin. It is found to be less than unity except (F1, F4, F6, F9, F10 and
F11) samples. Also we note that the average values of dose rate for samples
vary between (15.41 to 826.16) nGy/h. These values are lower than
the international average mean value 59 nGy/h (UNSCEAR, 2000)
except samples (F1, F3, F4, F6, F9, F10 and F11).
While, the values of the effective dose rate for samples vary
between (0.01 to 1.01) mSv/y. These values are lower than the
permissible limit ”1mSv/y” that recommended by the International
Commission Radiological Protection as the maximum annual dose to
the public members except sample F9.
We noticed that there are a good correlation between (238U to
226Ra), which clear the equilibrium in the uranium series. Also there
are a good correlation between (238U and 232Th), while there is a poor
correlation between (232Th and 40K) and (238U and 40K).
The radon exhalation rates for samples are also calculated. The
values of emanation factor (F) ranges from 0.31 to 0.81, emanation
coefficient of Radon ARn ranged from (10.33 to 662.20) Bq/Kg and
Radon mass exhalation rate ERn are ranged from (0.72 to 1616.46)
mBq/Kg sec. The highest value of ERn was found in sample F6 which
also has the highest 226Ra activity.
Second, determination of heavy metals and toxic elements (Cd,
Cu, Fe, Mg, Mn, Ni, Pb and Zn) using Flam Atomic Absorption
Technique (FAAS).
The results show that contents of heavy metals varied significantly
in different types of fertilizers like; single super phosphate (SSP),
potash fertilizer (PF), zinc-sulfate (ZnSo4), urea (URA), organic
fertilizer (OF), nitrogen fertilizer (NF) and nitrogen phosphorus
potassium(NPK) depending on NPK ratio and fertilizer origin.