International Journal of Scientific & Engineering Research Volume 4, Issue3, March-2013 1

ISSN 2229-5518

Gross Beta Radioactivity in Underground Drinking Water from

Permanent Site of Usmanu Danfodiyo University Sokoto Nigeria

A. Saidu, K. A. Dabai, S.A Ogunsina, Y.D. Samsin, S.B. Muhammad

Abstract— The conditions to measure the gross beta radioactivity in water samples from the permanent site of Usmanu Danfodiyo University Sokoto in Sokoto State Nigeria were established. The gross beta radioactivity of water samples were measured using proportional gas counter. The result show that the gross beta radioactivity in most samples is higher than the maximum contaminant level of 1.0Bq/L set by WHO. The range of the measured activity was found to be between 0.300Bq/L to as high as 78.57Bq/L with a geometric mean of 4.0034Bq/L. The gross beta effective dose was found to be 1.046 mSv/yr.

Index Terms—Activity, Contaminant limit, Effective dose, Geometric mean, Gross alpha

1 INTRODUCTION

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ater is quite an essential necessity of life. It is a major constituent of the human body and his environment. It is
used by man for various purposes, ranging from agricultural to industrial, power generation and domestic consumption etc. However, human activities and some natural phenomenon are polluting this water and thus affecting its quality. Some of these human activities include sewage disposing, leaching of fertilizers from the soil, industrial wastes disposals etc. some of these waste disposals often contain radioactive materials which contribute significantly to the background activity of the water bodies[1].
Another form of water pollution is as a result of certain rock types containing radioactive elements referred to as Naturally Occurring Radioactive Materials (NORM). These materials disintegrate and thereby emitting alpha particles, beta particles or gamma radiation. Drinking water sourced from deep wells and boreholes are usually expected to have high concentration of radioactive nuclides. This is because they pass through fractures in bedrocks or within the soil which contains minerals deposits that might have radioactive constituents and thus leaking into the water ways. Radioactivity in drinking water is one of the major ways in which radionuclides from the environment gets into the human body, which might consequently lead to radiation-induced disorderness [2].

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 A. Saidu (Bsc Physics,M sc Radiation Biophysics) he is an academic staff in Physics Department, Usmanu Danfodiyo University Sokoto, Nigeria. E- mail: amsa_koko@yahoo.com

 K. A. Dabai is currently pursuing masters degree program in Renewable

Energy, Usmanu Danfodiyo University Sokoto, Nigeria. E-mail: akabirdabai@yahoo.ca

 S. A. Ogunsina (B sc Physics)

.Y. D. Samsin (B sc physics, M sc Radiation Biophysics Ph d student at

South Korea

 S. B. Muhammad is currently pursuing masters degree program in Phys-

ics, Usmanu Danfodiyo University Sokoto, Nigeria.

There is evidence from both human and animal studies that radiation exposure at low to moderate doses may increase the long term incidence of cancer and that the rate of genetic malformations may be increase by radiation exposure [3]. It is therefore important to determine the amount of radioactivity in drinking water for every area where people live in, so as to guard against its health hazards [4].
Some work has been done on measurement of radioactivity in water in Nigeria. Onoja determined gross alpha and beta activity in well water from Zaria area. The result shows geometric mean value of 75.53Bq/m3 (or 0.07553Bq/L) for beta activity [5]. Tajudeen did similar work in Gwammaja area of Kano metropolitan city and the result shows a geometric mean value of
0.05Bq/m3 for beta activity [6]. Habila worked on survey of gross
beta radioactivity in wells and boreholes from Jos city .The result shows ranges of beta activity from 0.25 to 9.64 Bq/L, with a Geometric mean of 1.56Bq/L [7]. Avwiri and Agbalagba surveyed gross beta radionulide activity in Okpare-Creek Delta State and reported that mean beta activity was 0.481Bq/L [8].
The maximum contaminant limit of radioactivity allowable in drinking water is 1.850Bq/L set by USEPA [9] and 1.0Bq/L as set by WHO for beta [10]. The geographical/geological formation of an area determines to extent the radionuclide present in water [8].
However Saidu worked on gross beta radioactivity in wells and boreholes water in Sokoto city. The result obtained from proportional counter shows that the beta activity for: wells ranges from 0.35 to 49.85 Bq/L with geometric mean of 4.86Bq/L; and that of boreholes ranges from 0.71 to 32.69 Bq/L with geometric mean of 3.38Bq/L [10]. These results also show activities above practical screening level. Although Saidu carried out his work
E-mail: sbmuhammad@ymail.com

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within Sokoto city but the water samples from Usmanu Danfodiyo University permanent site was not included. This is the reason why it deem necessary to carry out this research for the fact that the major source of drinking water on the campus is underground water.
The campus is located on longitude 13º05’13” to 13º09’45”N and latitude 5º10’15”N to 5º15’05”E. Its geology is consistent with the general geology of the Sokoto basin.
This paper presents beta activity in Bq/L for water from bore holes and wells from Usmanu Danfodiyo University Sokoto Permanent site, based on reference to USEPA maximum contaminant limit of 1.85Bq/L and WHO maximum contaminant limit of 1.0Bq/L [9], [10].
2 MATERIALS AND METHOD

2.1 Sample Collection and Preparation

The method applied to this sampling is the stratified random sampling technique. The mapped area was gridded into 63 of
1000m×1000m each. Each grid according to the scale has an
area of 1.0 square kilometer. A total of 20 habitated grids were outlined, one sample was collected from each. However 6 of the
samples were lost as a result of 2010 flooding disaster of the
(channel efficiency, and background count rate), volume of sample used and sample efficiency were entered.
For gross beta counting selective measurement was adopted.
High voltage of 1700V was used, and samples were counted for 5 cycles of 2700 sec per cycle. The Beta Count Rate, and Beta Activity, were calculated using (2) and (3) respectively [12].

= (2)

= (3) The beta activity is expressed as Activity Concentration, C in
Becquerel per liter (Bq/L) using the formula [13]:

C = (4) Where:
Rb is observed sample count rate (S-1), Rs is observed standard count rate (S-1), Ro is background count rate (S-1),

V is volume of sample in liters,

m is mass in milligrams of ignited residue from volume V,

Kwalkwalawa River and only 14 were finally analyzed .The

represent the specific activity of
K in KCl.
samples were prepared and analyzed at the Center for Energy Research and Training, Ahmadu Bello University, Zaria, Nigeria. The sample efficiency, background measurements and plateau test were carried out using standard methods [11],[12].

The sample efficiency, is given by [12]:

= ×100% (1) Where: WB is the weight of empty planchet,
The factor 1.020 was included in the final equation to correct for the 20ml of the Nitric acid added to the sample as a stabilizer.

3. RESULTS AND DISCUSSION

Preliminary results of the detector characterization for beta particles in the beta only mode are as shown in table 1.

Table 1: Beta Background, Channel efficiency and Channel

Detection Limit

Beta Back-

WB+S is the weight of planchet plus sample after

Channel

No
ground
Values (cpm)
Channel
Efficiency %
Detection
Limit
evaporation,

0.077 A (mg) is the expected mass of the residue in the planchette.

2.2 Gross Beta Counting

The gross beta counting equipment used in this work is a Eurisys System Low Background Multiple (eight) Channel Alpha and Beta detector. The equipment is a gas flow proportional counter with 450μg/cm3 and thick window of diameter 60mm. It allows simultaneous counting on eight 300mm or 55mm diameter samples. Alpha (α) and beta (β) activity measurement on compound sources can be selective, sequential or simultaneous. The procedure involves entering the present time, number of cycles and the operational voltage. Also the count characteristics
1 0.966 46.47 0.345
2 0.366 35.39 0.391
3* 0 0 0
4 0.482 38.79 0.34
5 0.423 40.66 0.335
6 0.302 42.94 0.259
7* 0 0 0
8 0.338 34.88 0.288

Average 0.48 39.86 0.326

* Channels 3 and 7 are faulty and not included
The results for the gross beta radioactivity concentrations for the water samples are reported in table 2. The errors quoted in the

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table represent the standard deviation from repetition of meas- urements.

Table 2: Sample Location and Activity Concentration Obtained

Fig 1: Histogram of Distribution of Beta Activity

* Represents boreholes sources
Table 1 shows that the background count rate ranges from 0.302 to 0.996 with an arithmetic mean of 0.480cpm. The result of the average efficiency of the different channels of the detector was found to be 39.86%. The limit of detection ranges from 0.259 to
0.391 with an arithmetic mean of 0.326. The overall result of the preliminary investigation indicates low background, good plateau and low detection limit.
Table 2 shows that the activity concentration ranges from 0.300
to 78.570Bq/L with geometric mean of 4.0034Bq/L.
The distribution of the activity is represented as a Histogram in
Fig 1.
From the result obtained, only 4 out of the 14 samples representing 28.57% satisfy the recommended contaminant limit of less than 1.0Bq/L recommended by WHO; and 5 samples representing 32.5% is below the limit of 1.85Bq/L set by USEPA.
Comparing the average value 4.12Bq/L of beta activity obtained
in this work with: 0.07553Bq/L obtained in Zaria by Onoja [5];
0.00005Bq/L in Kano by Tajudeen [6]; and 1.56Bq/L in Jos by Habila [7]; shows that Gross beta activity in Sokoto is relatively higher.
The higher value of Gross beta activity could be as a result of the geological formation of the area whose land is highly invaded with phosphorus, a by-product of phosphate that has potassium-
40 which is a beta and gamma emitter whose source is fertilizer

used by farmers. Thus regular program of environmental audit and monitoring is here by recommended.

4. CONCLUSION

Since only few samples of water from the bore holes and wells in Usmanu Danfodiyo University permanent site meet the recommendations of WHO and USEPA, majority do not meet the standard. There is therefore need for further screening for radioactivity from the bore holes and wells that are used for drinking because continue to use it may pose serious health side effects to the public users.

REFERENCES

[1] G. Gondar, ”Pollution” Available at: http://www.sambal.co.uk/pollution. [Accessed on 20th May,2011]
[2] United State Environmental Protection Agency (USEPA) (2010).”Exposure Pathways” [Online] Available at: http://www.epa.gov/rpdweb00/understand/pathways. [Ac- cessed on 5th, October,2010]

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[3] J. K.Otton, (1994). National Radioactivity in the Environment.[Online] Available at: http://energy.usgs.gov/factsheets/radioactivity. [Accessed on
5th, October,2010]
[4] World Health Organisation (WHO) (2006).”WHO Guide- lines for Drinking Water Quality”. 3rd Edition. Chapter 9 (Radiological Aspect).pp197-209.[Online] Available at: http://www.who.int/water_sanitation_health/dwq/gdwq3rev/e n/index. [Access Accessed on 11th, January,2011 ]

[5] R. A. Onoja, (2004). “Survey of Gross Alpha and Beta Radi- oactivity in Wells from Zaria”. [Unpublished] M.Sc. thesis

,Ahmadu Bello University, Zaria

[6] H.V. Tajudeen, (2006). Survey of Radioactivity in Wells and Bore holes from Gwammaja Area of Kano City. [Un- published] M.Sc. thesis, Ahmadu Bello University, Zaria .

[7] Habila, N. (2008). Survey of Gross Alpha and Beta Radioactivity in Jos City. Unpublished] M. Sc. thesis, University of Jos, Nigeria
[8] Avwiry G.O. and Agbalagba E.O. (2007). Survey of Gross
Alpha and Beta Radionuclide Activity in Okpare-Creek
Delta State .Nigerian Journal of Applied Sciences 7 (22):
3542-3546
[9] USEPA (1996).National Primary Drinking Water Regulations. United State Environmental Protection Agency Report EPA-570/9-76-03.[Online] Available at: http://yosemite.epa.gov/water/owrccatalog.nsf. [Accessed on
11th, January,2011 ]
[10] Saidu, A. (2010) Survey of Gross Alpha and Beta Radioactivity in Boreholes and Wells in Sokoto City. [Unpublished] M.Sc. thesis ,University of Jos
[11] ASTM (1995) Standard test method for alpha particle radioactivity of water. American Society for Testing and Materials (ASTM ) D1943-90 and D1890-90. [Online] Available at: http://www.astm.org/Standards/D1890. [Accessed on24th March,2010]
[12] ISO(1992). Water Quality Measurement for Gross Beta
Activity in Non Saline Water, Thick Source Method. International Organization of Standardization (ISO) 9697-
1992 revised, Geneva, Switzerland. [Online]. Available at:
http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue

_detail. [Accessed on 15th, April,2010]