**3.3 Annual gonad equivalent dose (AGED)**

The gonads, the active bone marrow, and the bone surface cells are classified as organs of interest by UNSCEAR (2003). The annual gonadal dose equivalent (AGED, mS vy�<sup>1</sup> ) owing to the specific activities of 226Ra, 232Th, and 40K was computed using [25]:

$$\text{AGED} \left(\mu\text{S} \,\text{vy}^{-1}\right) = \text{3.09C}\_{\text{Ra}} + \text{4.18C}\_{\text{Th}} + \text{0.314C}\_{\text{K}} \tag{2}$$

**Figure 1.**

*Percentage contribution of the three natural radionuclides measured in powdered milk.*

mean value of 56.2 17.0 Bq l<sup>1</sup>

**Milk samples Raeq**

Powder milk (Bq kg<sup>1</sup>

Liquid milk (Bq L<sup>1</sup>

Condensed Peak

Bridel milk (foreign)

Lady Liberty (foreign)

milk

**Table 2.**

**66**

**(Bqkg<sup>1</sup>**

)

) <sup>10</sup><sup>3</sup>

**/Bq l<sup>1</sup> )**

*Multifunctionality and Impacts of Organic and Conventional Agriculture*

**AGED (μSvy<sup>1</sup> )**

Peak milk 81.7 17.9 290.6 0.3 200.2 0.7 Peak Chocó milk 67.9 18.0 239.1 0.2 166.3 0.6 Cowbell milk 60.6 20.8 208.3 0.2 146.2 0.5 Cowbell Chocó milk 70.8 18.3 258.2 0.2 177.2 0.2 Nunu milk 65.7 19.4 230.8 0.2 196.7 0.6 Loya milk 67.0 21.1 235.0 0.2 164.8 0.6 Miksi milk 78.8 22.3 285.3 0.3 197.7 0.2 Coast milk 70.2 19.9 245.8 0.2 171.2 0.7 Real milk 82.4 24.3 290.7 0.3 202.6 0.7 Dano milk (foreign) 80.4 19.2 285.0 0.3 160.4 0.6 Mean value 72.6 20.1 256.9 0.25 178.4 0.6 Global standard 370 300 ≤1.0 450 0.29 (mS vy<sup>1</sup>

Hollandia milk 54.9 18.1 191.0 0.2 134.4 0.5 Vital milk 53.7 18.8 184.8 0.2 177.1 0.6 Nutric milk 72.0 20.3 256.4 0.3 163.8 0.6 Peak milk 65.0 15.8 235.6 0.2 99.6 0.3 Three Crown milk 48.0 14.5 170.6 0.2 147.2 0.5 Olympic milk 41.5 12.7 142.9 0.2 131.5 0.5 Coast milk 61.1 20.5 210.2 0.2 146.7 0.5 Nunu milk 54.9 15.6 187.1 0.2 114.8 0.4

**Hin AEDE (μSvy<sup>1</sup> )** **ELCR <sup>10</sup><sup>3</sup> (mS vy<sup>1</sup> )**

)

)

. All the values obtained are within the international

acceptable limit for Raeq and therefore comply with the radium equivalent standard for radioactivity concentration. The percentage contributions of the three naturally occurring radionuclides in the powdered and liquid milk samples are shown in **Figures 1** and **2**, respectively. These percentages were calculated based on the estimation that 1 Bq kg<sup>1</sup> of 226Ra, 0.7 Bq kg<sup>1</sup> of 232Th, and 13 Bq kg<sup>1</sup> of 40K produce the same radiation dose rates in the radium equivalent [24]; the average percentage contribution of 40K is 42%, and for 226Ra the percentage contribution to the entire milk content is 20%, while 232Th percentage contribution to the powdered milk samples is 38%. The percentage contribution of the three natural

Mean value 173.2 0.20 135.9 0.5 World standard 370 300 ≤1.0 450 0.29 (mS vy<sup>1</sup>

*Mean radium equivalent and summary of computed radiological risk parameter of milk samples.*

61.1 18.0 209.3 0.2 132.5 0.5

48.4 14.6 163.9 0.2 129.5 0.5

55.3 18.3 189.1 0.2 117.7 0.4

where CRa, CTh, and CK represent the radioactivity levels of 226Ra, 232Th, and 40K, respectively.

If the radioactivity of the food source is higher than the world permissible value of 0.30 mSvy�<sup>1</sup> , the model suggests that the food product is a potential source of radiological health risk to the consumer. In the studied powdered milk samples, AGED activity concentration varied from 208.3 μS vy�<sup>1</sup> to 290.7 μS vy�<sup>1</sup> , whereas in liquid milk samples analyzed, the estimated activity levels varied from 170.6 μS vy�<sup>1</sup> to 256.4 μSvy�<sup>1</sup> . Although the obtained 290.7 μS vy�<sup>1</sup> activity concentration value in *Real* powdered milk is approximately the maximum permissible limit value, all other obtained estimated values in both liquid and powdered brands of milk sampled are well within the global maximum permissible values of 300 μS vy�<sup>1</sup> [26]; thus the different milk samples examined may not cause any immediate radiological health side effects in terms of AGED index.

#### **3.4 Internal gamma indices**

The internal hazard (*Hin*) index is defined according to Zarie and Al-Mugren [27] as:

$$H\_{\rm in} = \mathrm{C\_{\rm R}}/\_{\rm 185} + \mathrm{C\_{\rm R}}/\_{\rm 259} + \mathrm{C\_{\rm k}}/\_{\rm 4810} \tag{3}$$

radiologically safe going by the global recommended permissible limit of annual

*Economic Approach to Risk Analysis of Naturally Occurring Radioactive Materials (NORMs)…*

Excess life cancer risk predicts the likelihood of developing cancer over a lifetime at a certain exposure rate. It is a value representing the number of extra cancers expected in a given number of people on exposure to a carcinogen at a given

The parameters used are defined; thus AEDE is the annual effective dose equivalent, DL is average duration of life (estimated to be 70 years), and RF is the risk factor (S/v), i.e., fatal cancer risk per Sievert. ICRP uses a RF of 0.05 for the public for stochastic effects [32]. The intake of milk containing an elevated level of radionuclide may increase the chance of cancer risk. If the radioactivity in the milk is higher than the world average, it could be a source of radiation to the human body and some specific organs, in that their ELCR would be greater than the world average of 0.29 mS vy�<sup>1</sup> in such body. The estimated ELCR obtained in all the

**Table 3** presents the estimated values of the annual effective dose of the three

**Table 4** shows the dose conversion factor for the three different age groups used

"The annual effective dose ED to individuals due to the ingestion of the radio-

activity concentration of the radionuclides in milk; *E* is the dose conversion factor

for the annual accumulated maximum and minimum effective ingestion doses are

different age groups show that the annual ingestion dose exceeded the UNSCEAR [26], maximum permissible limit by 68% for the infants, and 2.8% for the children; however, the adult value is 22.6% below the recommended maximum permissible limit. This obtained result indicates that the ingestion rate of milk by infants and

**Table 3** presents the result of the computed annual ingestion dose to the three age groups (infants, children, and adults), with an estimated annual milk intake of 15 kg, 14 kg, and 10 kg, respectively, and using the conversion factor values in **Table 4**. The results obtained indicate that the infants' accumulated maximum and

ELCR ¼ AEDE � DL � RF (5)

ED ¼ Ac � Iin � E (6)

. For the children, the obtained values

, respectively, with an average dose rate of

. The obtained dose rates in the three

. The accumulated maximum and minimum annual effective ingestion

), *Ac* is the

, respectively,

, respectively, with an

Excess lifetime cancer risk is given as Taskin et al. [32]:

measured samples is lower than the international standard limit.

nuclides in powder and liquid milk is estimated using the equation.

where the parameters; *ED* is the annual effective dose in (Svy�<sup>1</sup>

and *Iin* is the annual intake of milk with respect to the age group" [15].

minimum effective dose values are 1743.0 μS vy�<sup>1</sup> and 892.7 μS vy�<sup>1</sup>

doses obtained for adults are 235.1 μS vy�<sup>1</sup> and 122.3 μS vy�<sup>1</sup>

**3.7 Annual effective dose for different age groups**

with an average dose rate of 1345.4 μS vy�<sup>1</sup>

average annual dose rate of 181.1μSvy�<sup>1</sup>

1048.9 μS vy�<sup>1</sup> and 546.8 μS vy�<sup>1</sup>

822.5 μS vy�<sup>1</sup>

**69**

age groups of infants, children, and adult represented in this evaluation.

in estimating the annual effective dose rate to individual consumption of the

effective dose rate.

dose.

**3.6 Excess lifetime cancer risk**

*DOI: http://dx.doi.org/10.5772/intechopen.92279*

various milk samples in Nigeria.

where *CRa*, *CTh*, and *CK* represent the radioactivity levels of 226Ra, 232Th, and 40K correspondingly. *Hin* should be less than the unity for the radiation risk to be insignificant.

The internal hazard index (*Hin*) estimates the internal exposure rate to oncogenic radon nuclides and its short-lived progeny. The mean radioactivity values of the computed *Hin* for powdered and liquid milk products are 0.3 and 0.2, respectively, which are well below the unity value recommended as the permissible limit. It is observed from the values obtained that powdered milks contain more of the natural radionuclides than liquid milk samples, which may be a result of the activity concentration through evaporation to dryness of the raw liquid milk. But all the milk samples analyzed met the minimum internal gamma index requirement for consumption.

#### **3.5 Annual effective dose equivalent (AEDE)**

The annual effective dose equivalent received was computed from absorbed dose rate by applying a dose conversion factor of 0.7 Sv Gy�<sup>1</sup> and the occupancy of 0.8 (19/24) recommended by UNSCEAR [26] and Veiga et al. [28]. Therefore, the annual effective dose equivalent (μS vy�<sup>1</sup> ) was calculated using the formula [26]:

$$\text{AEDE } \left(\mu\text{S } \text{vy}^{-1}\right) = \text{absorbed dose } \left(\text{nG } \text{yh}^{-1}\right) \times \\$760 \text{ h} \times 0.7 \text{ SvGy}^{-1} \times 0.8 \times 10^{-3} \text{ s} \tag{4}$$

The estimated annual effective dose equivalent obtained for the powdered and liquid milk brands analyzed is shown in **Table 2**. The values obtained for the powdered milk varied from 146.2 μS vy�<sup>1</sup> to 202.6 μS vy�<sup>1</sup> with a mean activity dose level of 178.4 μS vy�<sup>1</sup> , while in the liquid milk, the activity dose levels ranged from 99.6 μS vy�<sup>1</sup> to 177.1 μS vy�<sup>1</sup> with a mean activity concentration of 135.9 μS vy�<sup>1</sup> . The obtained result shows that the milk samples surveyed have their annual effective dose equivalent values lower than the world average values of 450 μS vy�<sup>1</sup> [26, 29–31]. This result shows that the various sampled milk brands are *Economic Approach to Risk Analysis of Naturally Occurring Radioactive Materials (NORMs)… DOI: http://dx.doi.org/10.5772/intechopen.92279*

radiologically safe going by the global recommended permissible limit of annual effective dose rate.

#### **3.6 Excess lifetime cancer risk**

where CRa, CTh, and CK represent the radioactivity levels of 226Ra, 232Th, and

radiological health risk to the consumer. In the studied powdered milk samples, AGED activity concentration varied from 208.3 μS vy�<sup>1</sup> to 290.7 μS vy�<sup>1</sup>

centration value in *Real* powdered milk is approximately the maximum permissible limit value, all other obtained estimated values in both liquid and powdered brands

The internal hazard (*Hin*) index is defined according to Zarie and Al-Mugren

where *CRa*, *CTh*, and *CK* represent the radioactivity levels of 226Ra, 232Th, and 40K

The internal hazard index (*Hin*) estimates the internal exposure rate to oncogenic radon nuclides and its short-lived progeny. The mean radioactivity values of the computed *Hin* for powdered and liquid milk products are 0.3 and 0.2, respectively, which are well below the unity value recommended as the permissible limit. It is observed from the values obtained that powdered milks contain more of the natural radionuclides than liquid milk samples, which may be a result of the activity concentration through evaporation to dryness of the raw liquid milk. But all the milk samples analyzed met the minimum internal gamma index requirement for

The annual effective dose equivalent received was computed from absorbed dose rate by applying a dose conversion factor of 0.7 Sv Gy�<sup>1</sup> and the occupancy of 0.8 (19/24) recommended by UNSCEAR [26] and Veiga et al. [28]. Therefore, the

AEDE <sup>μ</sup>S vy�<sup>1</sup> <sup>¼</sup> absorbed dose nG yh�<sup>1</sup> � 8760 h � <sup>0</sup>*:*7 SvGy�<sup>1</sup> � <sup>0</sup>*:*<sup>8</sup> � <sup>10</sup>�<sup>3</sup>

The estimated annual effective dose equivalent obtained for the powdered and

liquid milk brands analyzed is shown in **Table 2**. The values obtained for the powdered milk varied from 146.2 μS vy�<sup>1</sup> to 202.6 μS vy�<sup>1</sup> with a mean activity

annual effective dose equivalent values lower than the world average values of 450 μS vy�<sup>1</sup> [26, 29–31]. This result shows that the various sampled milk brands are

from 99.6 μS vy�<sup>1</sup> to 177.1 μS vy�<sup>1</sup> with a mean activity concentration of

*=*<sup>185</sup> þ *CTh=*<sup>259</sup> þ *CK=*

correspondingly. *Hin* should be less than the unity for the radiation risk to be

in liquid milk samples analyzed, the estimated activity levels varied from

*Multifunctionality and Impacts of Organic and Conventional Agriculture*

of milk sampled are well within the global maximum permissible values of 300 μS vy�<sup>1</sup> [26]; thus the different milk samples examined may not cause any

immediate radiological health side effects in terms of AGED index.

*Hin* ¼ *CRa*

If the radioactivity of the food source is higher than the world permissible value

, the model suggests that the food product is a potential source of

. Although the obtained 290.7 μS vy�<sup>1</sup> activity con-

, whereas

<sup>4810</sup> (3)

) was calculated using the formula [26]:

, while in the liquid milk, the activity dose levels ranged

. The obtained result shows that the milk samples surveyed have their

(4)

40K, respectively.

of 0.30 mSvy�<sup>1</sup>

[27] as:

insignificant.

consumption.

**3.5 Annual effective dose equivalent (AEDE)**

annual effective dose equivalent (μS vy�<sup>1</sup>

dose level of 178.4 μS vy�<sup>1</sup>

135.9 μS vy�<sup>1</sup>

**68**

170.6 μS vy�<sup>1</sup> to 256.4 μSvy�<sup>1</sup>

**3.4 Internal gamma indices**

Excess life cancer risk predicts the likelihood of developing cancer over a lifetime at a certain exposure rate. It is a value representing the number of extra cancers expected in a given number of people on exposure to a carcinogen at a given dose.

Excess lifetime cancer risk is given as Taskin et al. [32]:

$$\text{ELCR} = \text{AEDE} \times \text{DL} \times \text{RF} \tag{5}$$

The parameters used are defined; thus AEDE is the annual effective dose equivalent, DL is average duration of life (estimated to be 70 years), and RF is the risk factor (S/v), i.e., fatal cancer risk per Sievert. ICRP uses a RF of 0.05 for the public for stochastic effects [32]. The intake of milk containing an elevated level of radionuclide may increase the chance of cancer risk. If the radioactivity in the milk is higher than the world average, it could be a source of radiation to the human body and some specific organs, in that their ELCR would be greater than the world average of 0.29 mS vy�<sup>1</sup> in such body. The estimated ELCR obtained in all the measured samples is lower than the international standard limit.

**Table 3** presents the estimated values of the annual effective dose of the three age groups of infants, children, and adult represented in this evaluation.

**Table 4** shows the dose conversion factor for the three different age groups used in estimating the annual effective dose rate to individual consumption of the various milk samples in Nigeria.

#### **3.7 Annual effective dose for different age groups**

"The annual effective dose ED to individuals due to the ingestion of the radionuclides in powder and liquid milk is estimated using the equation.

$$\mathbf{E\_D = A\_c \times I\_{\rm in} \times E} \tag{6}$$

where the parameters; *ED* is the annual effective dose in (Svy�<sup>1</sup> ), *Ac* is the activity concentration of the radionuclides in milk; *E* is the dose conversion factor and *Iin* is the annual intake of milk with respect to the age group" [15].

**Table 3** presents the result of the computed annual ingestion dose to the three age groups (infants, children, and adults), with an estimated annual milk intake of 15 kg, 14 kg, and 10 kg, respectively, and using the conversion factor values in **Table 4**. The results obtained indicate that the infants' accumulated maximum and minimum effective dose values are 1743.0 μS vy�<sup>1</sup> and 892.7 μS vy�<sup>1</sup> , respectively, with an average dose rate of 1345.4 μS vy�<sup>1</sup> . For the children, the obtained values for the annual accumulated maximum and minimum effective ingestion doses are 1048.9 μS vy�<sup>1</sup> and 546.8 μS vy�<sup>1</sup> , respectively, with an average dose rate of 822.5 μS vy�<sup>1</sup> . The accumulated maximum and minimum annual effective ingestion doses obtained for adults are 235.1 μS vy�<sup>1</sup> and 122.3 μS vy�<sup>1</sup> , respectively, with an average annual dose rate of 181.1μSvy�<sup>1</sup> . The obtained dose rates in the three different age groups show that the annual ingestion dose exceeded the UNSCEAR [26], maximum permissible limit by 68% for the infants, and 2.8% for the children; however, the adult value is 22.6% below the recommended maximum permissible limit. This obtained result indicates that the ingestion rate of milk by infants and


**Table 5** shows the optimized annual consumption rate to stay within the inter-

*Economic Approach to Risk Analysis of Naturally Occurring Radioactive Materials (NORMs)…*

Following the exceeding of the UNSCEAR [26] μSvy<sup>1</sup> permissible limit from the recommended quantity of milk to be consumed by the three age groups, **Table 5**

40K Average 137.59 66.92 238U Average 129.70 169.84 232Th Average 482.79 519.09

40K Average 106.71 53.67 238U Average 127.49 172.64 232Th Average 483.36 537.42

*Annual effective dose to infants and children with a proposed annual consumption of 7 and 11 kg, respectively,*

Lungs 0.8 0.5 0.1 Ovaries 0.8 0.5 0.1 Bone marrow 0.9 0.5 0.1 Testes 1.1 0.6 0.1 Kidneys 0.8 0.5 0.1 Liver 0.6 0.4 0.1 Whole body 0.9 0.5 0.1

Lungs 0.7 0.4 0.1 Ovaries 0.6 0.4 0.1 Bone marrow 0.7 0.5 0.1 Testes 0.9 0.5 0.1 Kidneys 0.7 0.4 0.1 Liver 0.5 0.3 0.1 Whole body 0.7 0.5 0.1

*of powder milk samples and 8 and 13 kg, respectively, for liquid milk.*

**Organs Effective dose rate to organs (mS vy<sup>1</sup>**

**Organs Effective dose rate to organs (mSvy<sup>1</sup>**

*Dose rate to different organs of the body due to radionuclides in powder and liquid milk.*

Accumulated average 750.1 755.9

Accumulated average 717.6 763.7 UNSCEAR 2000 standard 800 800

**Infants Children Adult**

**Infants Children Adult**

**Annual effective dose (μSv) Infants Children**

**): powdered milk**

**): liquid milk**

national recommended range.

*DOI: http://dx.doi.org/10.5772/intechopen.92279*

Radionuclides in powdered milk

Radionuclides in liquid milk

**Table 5.**

**Table 6.**

**71**
