Determination of Polycyclic Aromatic Hydrocarbons in the Water, Soils and Surface Sediments of ...

181 Pages·2016·1.62 MB·English

by  Alexis Munyengabe (212562429)

Determination of Polycyclic Aromatic Hydrocarbons
in the Water, Soils and Surface Sediments of the
Msunduzi River, KwaZulu-Natal, South Africa

By
Alexis Munyengabe

A thesis submitted to the College of Engineering, Agriculture and Science,
Pietermaritzburg Campus, University of KwaZulu-Natal, in fulfilment of the
academic requirements for the Masters of Science in Environmental Chemistry
School of Physics and Chemistry
University of KwaZulu-Natal
Pietermaritzburg
South Africa

Supervisors: Dr B. Moodley
Dr A. Mambanda

January 2016
Declaration

I, Alexis MUNYENGABE, hereby affirm that the work reported in this thesis is my
own contribution and where other people’s work was incorporated it was fully
acknowledged by the means of citations. The thesis has not been submitted to any
other University for a qualification award.
This work was carried out in the School of Chemistry and Physics, Pietermaritzburg
Campus, CAES, University of KwaZulu-Natal.

Signed (candidate)…………………………
………………..day of …………..2016
Signed Co-supervisor………………………..
………………day of ……………2016
Signed Supervisor…………………………..
…………….day of …………….2016

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Research meetings

Poster presentations:
 College of Agriculture, Engineering and Science (CAES), UKZN Research day:
22nd September 2015. Poster title: Determination of Polycyclic aromatic
hydrocarbons in the water, soils and the surface sediments of the Msunduzi
River in KwaZulu-Natal.

 42nd National Conference of SACI: 29th November-4th December 2015, Durban.
Poster title: Determination of Polycyclic aromatic hydrocarbons in the water,
soils and the surface sediments of the Msunduzi River in KwaZulu-Natal.

………………………..…………………………………
Signature
Alexis Munyengabe

Date: ……………………………………..
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Dedication

To the Almighty God

To my late father

To my mom

To my uncles and aunts

To my brother and sisters

To my friends and family

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Acknowledgements

I want to thank the Almighty God, the Sustainer of life and the Lord of this universe,
for protecting and helping me through this study.
I would like to express my sincere gratitude to my supervisors Dr Brenda Moodley
and Dr Allen. Mambanda for funding, supervision of this work and their guidance in
the writing up of this thesis.
I want to thank Prof. P. Ndungu and my research group for their assistance in the
collection of samples from the field.
I would also like to thank the following people in the school of Chemistry and Physics
(PMB): Ms C. Janse van Rensburg for mentorship in the operation of the GC-MS
instrument, Dr Simba G. Nyamato, Mr A. Panyako, Mr M. Sitati, Mr G. Rugiranka, Mr
J. N. Namugize and Dr Milindi S. Sibomana for mentorship in the laboratory and
writing up of the thesis.
I thank my family and friends for their support, especially my host, Dr F.
Habyarimana and his family for taking me up in his home.

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Table of Contents

Declaration ............................................................................................................. i
Research meetings .................................................................................................ii
Dedication ........................................................................................................... iii
Acknowledgements .............................................................................................. iv
Table of Contents .................................................................................................. v
List of Figures ....................................................................................................... x
List of Tables .......................................................................................................xii
List of Plates ....................................................................................................... xiv
List of acronyms and abbreviations .................................................................... xv
Abstract ............................................................................................................... xx
Chapter I................................................................................................................ 1
Introduction .......................................................................................................... 1
1.1 Source and Occurrence of PAHs in the Environment ......................... 1
1.2 Chemical and Physical Properties of PAHs .......................................... 5
1.3 Reactivity of PAHs .................................................................................... 9
1.4 Source Apportionment of PAHs........................................................... 11
1.5 Exposure and pathways of PAHs ........................................................ 12
1.6 Environmental Fate ................................................................................ 13
1.7 Justification of the Study ........................................................................ 16
1.9 Aims and Objectives ............................................................................... 18
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Chapter II ............................................................................................................ 20
Literature review ................................................................................................. 20
2.1 Extraction Techniques and Instrumental Methods Used in the
Analysis of Semi- and Non-volatile Organic Pollutants ......................... 20
2.1.1 Pre-treatment of environmental samples ...................................... 20
2.1.2 Methods for extracting persistent organic pollutants from
environmental samples ............................................................................. 21
Choice of solvents ................................................................................ 22
2.1.2.1 Extraction of PAHs from water samples ................................ 23
Liquid-liquid extraction (LLE) technique ........................................ 23
2.1.2.2 Extraction of PAHs from solid samples .................................. 25
Soxhlet extraction (SE) ........................................................................ 25
2.1.2.3 Purification of crude extracts by column chromatography . 28
2.2 Chromatographic Methods of Separating POPs ................................ 29
2.2.1 Gas chromatography (GC) ........................................................... 30
2.2.2 Gas chromatography-mass spectrometry (GC-MS) ................. 33
2.2.2.1 Ionization sources .................................................................... 35
Electron impact ionization (EI) ....................................................... 35
Chemical ionization (CI) ................................................................. 35
2.2.2.2 Mass analysers ......................................................................... 36
Full scan (FS) mode .......................................................................... 36
Selective ion monitoring (SIM) mode............................................ 37
2.2.2.3 Electron-multiplier detectors (EMDs) .................................. 37
2.3 Preparation of Calibration Curves Using the Internal Calibration
Method ............................................................................................................ 38
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2.4 Reliable approach to quantification of trace level amounts of
analytes from environmental samples ....................................................... 39
2.5 Applications of GC-MS Method for the Analysis of PAHs and
Other Related POPs ...................................................................................... 39
Chapter III ........................................................................................................... 42
Methodology ........................................................................................................ 42
3.1 Understanding the Study Area and its Impacts on the Pollution of
the Msunduzi River from Persistent Organic Pollutants ........................ 42
3.1.1 Description of KwaZulu-Natal Province ......................................... 42
3.1.2 Location of sampling sites in KZN Province ................................... 42
3.1.3 Detailed descriptions of sampling sites ............................................ 45
Henley Dam outlet area (HD) .................................................................. 45
Camp’s Drift area (CD) ............................................................................. 45
Du Toit Viljoen (DuTV) Bridge ................................................................ 46
Darvill wastewater treatment plant (DWWTP) area ............................ 47
Agriculture area (AA) ............................................................................... 48
Msunduzi town area (MT) ....................................................................... 48
Junction of Umgeni and Msunduzi Rivers (JUM) ................................ 48
3.1.4 Sampling plan ....................................................................................... 49
3.1.5 Experimental ......................................................................................... 52
3.1.5.1 Extraction of PAHs ........................................................................ 52
Liquid-liquid extraction of PAHs from the water and the
wastewater ............................................................................................... 52
Soxhlet extraction of PAHs from the surface sediments and the
soils ........................................................................................................... 53
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3.1.5.2 Purification of extracts .................................................................. 53
3.1.5.3 Instrumental analysis .................................................................... 54
GC-MS analysis conditions ................................................................... 54
Reagents and standards ......................................................................... 55
Preparation of calibration solutions ..................................................... 55
Quality assurance ................................................................................... 56
3.1.5.4 Analysis of PAHs by GC-MS ....................................................... 57
Chapter IV ........................................................................................................... 59
Results and discussions ...................................................................................... 59
4.1 Calculation of Limit of Detection, Limit of Quantification and
Quality Control of Analysis ........................................................................ 59
4.2 Physical parameters and concentrations of PAHs in the Msunduzi
River Basin ..................................................................................................... 63
4.2.1 Conductivity, pH and temperature of the Msunduzi River
water ............................................................................................................ 63
4.2.2 Concentration of PAHs in the surface water and the wastewater
....................................................................................................................... 67
Autumn season of 2014 .......................................................................... 68
Winter season of 2014 ............................................................................ 73
Spring season of 2015 ............................................................................. 77
Summer season of 2014 .......................................................................... 81
4.2.3 Concentration of PAHs in soil collected from the banks of the
river .............................................................................................................. 85
Autumn season of 2014 .......................................................................... 85
Winter season of 2014 ............................................................................ 89
Spring season of 2015 ............................................................................. 91
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Summer season of 2014 .......................................................................... 94
4.2.4 Concentrations of PAHs in the surface sediments from the
Msunduzi River.......................................................................................... 98
Autumn season of 2014 .......................................................................... 98
Winter season of 2014 .......................................................................... 102
Spring season of 2015 ........................................................................... 105
Summer season of 2014 ........................................................................ 108
4.3 Seasonal Variations of PAH Concentration and Physical Parameters
of the Water .................................................................................................. 112
4.4 Source Apportionment of PAHs in this Study ................................. 114
Chapter V .......................................................................................................... 118
Conclusion and recommendations .................................................................... 118
5.1 Conclusion ............................................................................................. 118
5.2 Recommendations ................................................................................ 119
Bibliography ...................................................................................................... 122
Appendices ........................................................................................................ 153

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