ABSTRACTS

The assessment of microbiological quality of Onuimo section of Imo River was carried out. The water samples were collected once a week for five weeks. The standard microbiological procedure involving filtration technique was used. The results obtained varied significantly with sampling time. The pH was lowest in week 2 (6.24b±0.61)  and has the highest value in week 5 (6.63a±0.07), Temperature was lowest in week 2 (28.72a±0.51)  and higher in week 3 (29.39a ± 0.66), Hardness was lowest in week 1 (7.79c ±1.86) and the highest value was obtained in week 2 (36.52a± 7.62), also the Total solids has the lowest value in week 5 (250.00a ± 37.33) and highest value in week 1 (269.44a ± 37.91), The result of  Nitrate was lower in week 4 (0.16a ± 0.08) and higher in week 5 (0.19a ± 0.10). The results obtained were compared with World Health Organization standard and most of the physicochemical parameters investigated fall below the WHO accepted standards. The microbiological quality revealed that the Total Bacterial Count obtained has the lowest value in week 3 (43.00c ± 8.80) and has the highest value in week 4 (108.89a ± 13.54), the Total Fungi Count was lowest in week 1 (4.89b ± 1.90) and higher in week 4 (8.56a  ± 1.81), and the  Total Coliform Count was lower in week 3 (90.00b ± 24.06) and higher in week 5 (129.78b ± 34.89). Some of these parameters studied were significantly (P< 0.05) different among the sampling points. Eight (8) bacterial isolates were obtained from the study and were identified as Staphyloccus, Pseudomonas, Proteus species, Salmonella species, Escherichia coli, Enterobacter, Bacillus species and Streptococcus. The fungi isolates were identified as Aspergillus species, Penicillum species, Rhizopus species and yeast. From the results obtained, the water quality assessment identified faecal contamination from humans and warm blooded animals, sewage runoff and effluents and also human activities around the river as the major sources of contamination. Thus, the water from Onuimo section of Imo River was considered unsuitable for direct human use and it poses a serious threat to the health of the consumers. Hence efforts should be made to treat the water before being used for above mentioned purpose as well as creating awareness on the associated potential health risk. 

TABLE OF CONTENTS

Certification i

Dedication ii

Acknowledgements iii

Table of Contents iv

List of Tables vii

List of Figures viii

Abstract ix

CHAPTER 1 1

INTRODUCTION 1

1.1 Background information 1

1.2 Significance of the study 3

1.3 Scope of the study 4

1.4 Aims and objectives of the study 4

1.5 Justification of the study 4

1.6 Limitations of the study 4

CHAPTER 2 5

LITERATURE REVIEW 5

2.1 Overview of water 5

2.2 Sources of water 6

2.2.1 Surface water 7

2.2.2 Ground water 7

2.3 Water pollution 7

2.4 Categories of water pollution 8

2.4.1 Point sources 8

2.4.2 Non-point sources 8

2.5 Risks of microorganisms to human health 8

2.5.1 Examples of at-risk concentration levels 9

2.6 Microbiological analysis of water 10

2.7 Methods of assessing microbial quality in water 11

2.7.1 Filtration method of assessing microbial quality in water 12

2.7.2 Standard plate count 14

2.7.3    Multiple tube fermentation method 14

2.7.4    ATP testing 15

2.8 Advantages and disadvantages of filtration method of measuring bacterial

growth in water 16

2.8.1 Advantages of filtration method of measuring bacterial growth in water 16

2.8.2 Disadvantages of filtration method of measuring bacterial growth in water 17

CHAPTER 3 18

MATERIALS AND METHODS 18

3.1 Study area 18

3.2 Source of materials 18

3.3 Microbiological methods 18

3.3.1 Media preparation 18

3.3.2    Determination of microbial load of water sample 19

3.3.3 Determination of coliform load by membrane filtration technique 20

3.3.4 Characterisation of Bacterial Isolates 21

3.3.5 Characterization of Fungi Isolates 21

3.3.6 Determination of Occurrence 22

3.4 Determination of physico-chemical quality 22

3.4.1 Determination of pH 22

3.4.2 Determination of Temperature 23

3.4.3 Determination of Acidity 23

3.4.4 Determination of Total Hardness 23

CHAPTER 4 25

RESULTS 25

CHAPTER 5 33

DISCUSSION, CONCLUSION AND RECOMMENDATION 33

5.1      Discussion 33

5.2 Conclusion 36

5.3       Recommendation 36

REFERENCES

LIST OF TABLES

Table              Title                                                       Page

1.1: Risk Concentration Levels of E. coli (cfu/100ml) 10

4.1:    Physico-chemical properties of water at the Onuimo 

section of Imo River during the period of study 26

LIST OF FIGURES

Figure            Title                                                       Page

 4.1:    Microbial load count of water at the Onuimo section of Imo River 28

 4.2:    Percentage occurrence of bacteria found in water at the Onuimo 

section of Imo River 3

4.3:    Percentage occurrence of fungi found in water at the Onuimo 

section of Imo River 32