Determination the concentrations of radon gas and exhalation rate in some phosphate fertilizer using CR-39 track detector

Abstract

Although it is generally agreed that fertilizers come in two physical forms liquid and solid.The term liquid fertilizer applies to anhydrous ammonia, aqua ammonia, N solutions and liquid mixed fertilizers.Liquid N-P-K fertilizers are also known as fluid fertilizer they include true solutions which require no agitation and suspensions or slurry type mixtures of N, P and K, which require constant stirring to keep the solids suspended in the solution [3].

Collection of the samples
Nine samples of fertilizer were collected from many national marked from Baghdad city as shown in Table 1.

Fig. 4: The relation between radon gas concentration and track density in standard
samples [7].
The effective radium content C Ra in samples were calculated as; [8]: * * * * (3) where h: the distance from the sample to CR-39 detector.A: the area of the cup.K: the calibration factor which is equal to (3.9816 tracks.mm - d -1 /Bq.m -3 ) Te: the effective time calculated as Te = [T-λ Rn -1 (1-e -λRnT )] T: exposure time.The radon exhalation rate in terms of area in (Bq.m -2 .h - ) was calculated as follows [8,9]: where C: the integrated radon exposure measured by the CR-39 SSNTD (Bq.m -3 .h).
V: the effective volume of the container (m 3 ).λ: the decay constant of radon ( h -1 ).T: the exposure time (h), and A is the area covered by the container (m 2 ).
The radon exhalation rate in terms of mass E m in (Bq kg -1 h -1 ) was calculated as: where M is the mass of the sample (kg), the alpha index was calculated as [10].
Finally the concentrations of radon gas in fertilizer samples are shown in Table

Results
Fig. 5 shows the lowest of radon concentration was found in (S8) is equal to (161.9Bqm -3 ), the highest of radon concentration was found in (S3) is equal to (251.98Bqm -3 ) and the average value is equal to (208.01± 32.8Bqm -3 ).Fig. 6 shows the lowest of surface exhalation rate was found in (S8) is equal to (0.249Bq m -2 h -1 ), the highest of surface exhalation rate was found in (S3) is equal to (0.388Bq m -2 h -1 ) and the average value is equal to (0.320±0.06 Bq m -2 h -1 ).Fig. 7 shows the lowest of mass exhalation rate was found in (S8) is equal to (0.183Bq kg -1 h -1 ), the highest mass exhalation rate was found in (S3) and equal to (0.285Bq kg -1 h -1 ) and the average value is equal to (0.235 ± 0.04 Bq kg 1 h -1 ).Fig. 8 shows: the lowest of radium concentration was found in (S8) is equal to (0.365 Bq kg -1 ), the highest of radon concentration was found in (S3) is equal to (0.57 Bqkg -1 ) and the average value is equal to (0.47 ± 0.07 Bq kg -1 ).
Fig. 9 shows the lowest of alpha index was found in (S8) and equal to (0.0018), the highest of alpha index was found in (S3) equal to (0.0029) and the average value is equal to (0.0023 ±4x10 -4 ).

S7
h -1 ) h -1 ) is the track density of the standard sample (track/mm 2 ).The unknown concentration was obtained using the following relation: standard uranium weight (known) × concentration (known) = weight of the sample (known) × unknown concentration.Fig.4represents the obtained calibration curve for standard samples.

Table 1 : Symbols of fertilizer samples.
e.