ABSTRACT

Twenty (20) groundwater samples, four of which are control samples, comprising of ten (10)

borehole and ten (10) locally hand-dug wells were drawn randomly around British America

Tobacco Company, Zaria. Some physical parameters: temperature, pH, conductivity and total

dissolved solids were measured usingthermometer, pH meter and conductivity meter. The

samples were analysed for gross alpha and gross beta radiations using MPC-2000-DP

(01872140) single channel analyser, a low background alpha and beta detector. The

meantemperature, pH, conductivity and total dissolved solids in the water samples were found to

be 27.8 °C, 5.1, 393µS/cm and 244.8 mg/l respectively.For practical screening purposes in the

case of drinking water, the recommended guideline activity concentrations are 0.1 Bq/l for gross

alpha and 1.0 Bq/l for gross beta activity (WHO, 1993; 2003). The gross alpha and beta

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CHAPTER ONE

INTRODUCTION

1.1       Background

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 (USEPA, 2010). 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 increased by radiation

over exposure (Otton, 1994). 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

(WHO, 2006).

Groundwater could be contaminated by radioactive materials because terrestrial radioactivity

increases with depth in the earth crust (WHO, 1998). These radioactive materials occur

naturally and of most concern are the uranium and thorium series and the progenies (radon and

thoron). They contribute to the radioactivity of the rain and groundwater which in turn affects

drinking water. Due to these, drinking water from deep wells and boreholes are expected to

contain high concentrations of radioactive elements. Radioactive materials could also be

washed into wells, boreholes and even enter through burst pipes. Important radioactive elements

in drinking water are tritium, potassium-40, radium and radon which are alpha or beta emitters

(Surbeck, 1995). People who ingest polluted water can develop illness and with prolonged

exposure to radioactive polluted water could cause cancers, toxicity of the kidneys or bear

children with birth defects (WHO, 2006). Knowledge of the naturally occurring radionuclide

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present in drinking water enables one to assess any possible radiological hazards to humans by

the use of such water.

Manmade pollution of water is divided into two kinds: point source which is caused by

discharge of pollutants from specific location for example discharge from factories sewage

treatment plants and oil tankers into rivers, and non-point source which occurs from rainfall or

melting of snow and the run-off washes away pollutants into lakes, rivers and coastal waters.

Industrial waste is the most common source of water pollution in the present day (Ogedengbe

and Akinbile, 2004) and it increases yearly due to the fact that industries are increasing because

most countries are getting industrialized. Industries vary in size, nature of products,

characteristics of waste discharged and the receiving environment. The major industrial

categories in Nigeria are metals and mining, food, beverages and tobacco; breweries,

distilleries, textile, leather products, wood processing and manufacture, furniture, pulp and

paper industries and chemical and allied industries. Industrial effluents contain toxic and

hazardous materials from the wastes that settle in river water as bottom sediments and constitute

health hazards to the urban population that depend on the water as a source of supply for

domestic uses (Akaniworet al, 2007).

Groundwater quality is defined based on a set of health and safety regulations for domestic use.

The World Health Organization (WHO) guidelines for drinking water suggest performing an

indirect evaluation of committed dose by measuring gross alpha and beta radioactivity and

checking compliance to derived limit; the proposed limits are 0.1Bq/l for gross alpha and

1.0Bq/l for gross beta radioactivity(WHO, 2003).

Ground water used for public domestic supply must adhere to a set of regulatory objectives for

health and safety than ground water used strictly for irrigation needs. Groundwater

contamination occu