The uptake of heavy metals by aquatic macrophytes and the development of microsampling ...

288 Pages·2008·2.92 MB·English

The uptake of heavy metals by aquatic
macrophytes and the development of
microsampling analytical techniques.
Bateman, M.J.
Submitted version deposited in CURVE November 2008

Original citation:
Bateman, M.J. (1999). The uptake of heavy metals by aquatic macrophytes and the
development of microsampling analytical techniques. Unpublished PhD Thesis. Coventry:
Coventry University.

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THE UPTAKE OF HEAVY METALS BY
AQUATIC MACROPHYTES AND THE
DEVELOPMENT OF MICROSAMPLING
ANALYTICAL TECHNIQUES

MARK. J. BATEMAN

A thesis submitted in partial fulfilment of the
University’s requirements for the Degree of Doctor
of Philosophy

MARCH 1999

Coventry University

THE UPTAKE OF HEAVY METALS BY AQUATIC MACROPHYTES AND THE
DEVELOPMENT OF MICROSAMPLING ANALYTICAL TECHNIQUES
by

MARK. J. BATEMAN Bsc (Hons) MSc

A thesis submitted in partial fulfilment of the University’s requirements for the Degree
of Doctor of Philosophy

Sponsoring Establishment : Department of Natural and Environmental
Sciences,
Coventry University
Collaborating Establishment : Courtaulds Environmental Research
Division, Coventry

March 1999
ABSTRACT

THE UPTAKE OF HEAVY METALS BY AQUATIC MACROPHYTES AND
THE DEVELOPMENT OF MICROSAMPLING ANALYTICAL TECHNIQUES

by Mark Julian Bateman BSc. (Hons) MSc.

This thesis reviews literature relating both to the treatment of metal rich wastewaters by
the use of constructed wetlands and the use of slurry analytical procedures for the
determination of heavy metals in environmental micro-samples.

A survey of metal contaminated wetland sites showed that aquatic plants maintain low
levels of metals in aerial parts despite some very elevated sediment metal concentrations
and extreme acidity. A series of greenhouse trials investigated the uptake of metals into
aerial sections of Typha, Phragmites and Equisetum in long term hydroponic
experiments. Phragmites was shown to accumulate zinc to a higher level than Typha.
The toxicity of zinc supplied in the nutrient solution at 5 mg.dm-3 over long periods was
found to limit the viability of such non-sediment based systems. A reliable routine
analytical procedure was developed along with a program of quality control for the
study of metal uptake into aquatic plants.

A micro sampling technique, eminently suited for the analysis of small plant sections
was developed. This technique uses ozone to ash the plant samples at a low temperature
and following suspension in a liquid medium provides a sample ready for slurry
determinations by a variety of analytical instrumentation. It is proposed that this method
may also be suitable for the determination of metals in individual invertebrates and
other zoological micro-samples as well as potential applications in the medical field.
i
CONTENTS
Page
Abstract i.
Contents ii.
Acknowledgments iii
Chapters 1 - 5 contents pages iv
List of Tables ix
List of Figures xi
List of Plates xii
Glossary xiii
Chapter 1 Introduction 1
Chapter 2 The development of routine analytical procedures 74
Chapter 3 A survey of plants in heavy metal rich contaminated wetlands 107
Chapter 4 The uptake of metals in emergent aquatic plants under controlled
conditions 130
Chapter 5 The preparation and analysis of environmental samples by
slurry techniques 167
Chapter 6 Concluding remarks 234
References 236
Appendices 1 - 6 260
ii
ACKNOWLEDGMENTS

I would like to thank the following people for their assistance throughout this work,
without their kind and generous support the quality and strength of this research could
not have been attained.

Alan Newman and Anne Miller for the conception of the project and arrangement of
funding. Thanks cannot be extended enough to Alan Newman for an education in
analytical instrumentation, patience and loyalty. Humphrey Smith for moral and
academic support both in and out of office hours. Stephen Smith for invaluable help
with the identification of aquatic species and statistics. Support from within the School
has been widespread but especially from : Les Duckers, Phil Lorimer, Andrew Turner,
Diane Whitehouse. Anthony Smallwood who during his student work placement year
assisted in the running of greenhouse experiments. The many excellent technicians who
have assisted this multidisciplinary work deserve a special acknowledgment. Without
their kindness and willingness to help, this research would have been considerably
harder. They include : John Bickerton, Jeremy Brooker, Alan Cranston, Bob Hollyoak,
Jackie Hunter, Chris Lovering, Dave Moon, Jean Murch, Anne Nuttall, Paul Sephton,
Ken Smith, Malcom Taylor, Neil Thompson, Bill Wood.

Alan Cox (Sheffield University) for the loan of a bolling triple slot burner and
absorption tubes. Alan Baker (Sheffield University) for advice and supply of literature.
Ian Shuttler for the generous donation of a palladium solution.

Friends who have offered support, help and encouragement throughout my research :
Steve Berry, Emma Boyce, Stuart Duggan, Ian Fokerd, Nigel, Chris Foddy, Mike and
Jacob Jelleson, Helen Jones, Steve Jones & Lulu, Jim & Charlotte Maclaughlan, Boz
Morris, Dave Penny, Pete Shaw, Helen Smith, Seb West and Simon Wood.

This Thesis is dedicated to my mother and in memory of my father who sadly died
before its completion - I thank them both for generating my interest in science from an
early age and the installation of that rarity - common sense !
iii
CHAPTER 1. INTRODUCTION Page

1.1 Metals and the environment 1
1.2 Physical and chemical treatment of metal laden wastewaters 4
1.3 Treatment of municipal wastewater using aquatic plants 6
1.3.1 Lagoons and ponds 6
1.3.2 Constructed wetlands 7
1.3.2.1 The design of constructed wetlands 9
1.3.2.2 Substrate 10
1.3.2.3 Microorganisms 12
1.3.2.4 Plants 13
1.3.2.5 Oxygen transfer 14
1.3.2.6 Growth, harvesting and biomass 15
1.4 Biological treatment of non-municipal wastewaters 17
1.4.1 Urban run-off 17
1.4.2 Industrial wastewater & landfill leachate 17
1.4.3 Acid mine drainage (AMD) 18
1.4.3.1 Generation of acid mine drainage 19
1.4.3.2 Treatment of acidity 21
1.4.3.3 Removal of metals from AMD 22
1.4.4 Metallic wastewaters : Non-AMD 24
1.5 The uptake and accumulation of heavy metals by plants 27
1.5.1 Tolerance strategies in plants 28
1.5.2 Metal accumulation in aquatic plants 32
1.6 The determination of metals in waters, sediments and plants 38
1.6.1 Nebulisation methods 39
1.6.1.1 Flame atomic absorption spectroscopy 40
1.6.1.2 Inductively coupled plasma emission spectroscopy 42
1.6.1.3 Nebulisation and atomisation in FAAS and ICP-AES 43
1.6.2 Non-nebulisation methods 47
1.6.2.1 Delves cup 47
1.6.2.2 Electrothermal atomisation atomic absorption spectroscopy 53
1.6.2.3 Background correction in ETA-AAS and FAAS 61
1.6.2.4 Other atomisation methods for solid and slurry atomic
spectroscopy 64
1.6.2.5 Differential pulse anodic stripping voltammetry 65
1.6.2.5 X-ray fluorescence (XRF) spectroscopy 65
1.7 Analytical quality assurance 66
1.8 Justification of the research proposal 71
1.8.1 Summary of aims 73

iv
CHAPTER 2. THE DEVELOPMENT OF ROUTINE ANALYTICAL
PROCEDURES

2.1 Introduction 74
2.1.1 Dry ashing 75
2.1.2 Wet ashing in open vessels 77
2.1.3 Wet ashing by microwave digestion 78
2.2 Selection of batch digestion method 81
2.2.1 Equipment and reagents 81
2.2.2 Evaluation of a dry ashing procedure 82
2.2.3 Evaluation of wet digestion procedures - the acid test 84
2.2.4 Selection of digestion procedure - vegetation and sediment samples 85
2.2.5 Microwave digestion equipment and procedure 86
2.2.6 Comparison of microwave and hot plate digestion 88
2.2.6.1 Botanical samples 89
2.2.6.2 Sediment samples 91
2.2.6.3 Spike recovery 93
2.3 Quality assurance 95
2.3.1 Preparation of inhouse reference materials 95
2.3.2 Characterisation of inhouse reference materials 96
2.3.3 Analysis of certified reference materials 98
2.3.4 Spike recovery 102
2.4 Discussion 104
2.4 Conclusions 106
v
CHAPTER 3. A SURVEY OF PLANTS IN HEAVY METAL
CONTAMINATED WETLAND SITES

3.1 Introduction 107
3.1.1 The bio-availability of metals 108
3.1.2 Plant washing procedures 110
3.2 Description of field sites 112
3.2.1 Alvecote Pools 112
3.2.2 Wyken Slough 113
3.2.3 St. Cuthbert’s lead works 113
3.2.4 Hartshill quarry 113
3.3 Experimental 114
3.3.1 Equipment 114
3.3.2 Water collection and preparation 114
3.3.3 Sediment collection and preparation 115
3.3.4 Plant collection and preparation 115
3.4 A comparison of the site characteristics : the heavy metal content of water,
sediment and plants 116
3.4.1 Water analysis 116
3.4.2 Sediment analysis 117
3.4.3 Plant analysis 119
3.5 Discussion 125
3.6 Conclusions 128

vi
CHAPTER 4. THE UPTAKE OF HEAVY METALS IN EMERGENT AQUATIC
PLANTS UNDER CONTROLLED CONDITIONS

4.1 Introduction 130
4.2 The uptake of metals in emergent aquatic plants under controlled conditions
- experimental design 132
4.3 A comparison of the uptake of lead and zinc by Phragmites and Typha 136
4.3.1 Results 137
4.3.2 Discussion 140
4.4 The uptake of zinc by Phragmites and the removal from the system 142
4.4.1 The uptake of zinc into plant aerial sections 142
4.4.2 Changes in plant zinc concentrations after the cessation of dosing 143
4.4.3 The removal of zinc from solution 145
4.4.4 The effect on the uptake of zinc by harvesting plants 147
4.4.5 The effect of prolonged zinc exposure - growth and moisture content 148
4.4.6 Investigation of chlorotic leaves 150
4.4.7 Discussion 151
4.5 Removal of zinc by Phragmites in a flow-through tiered system 154
4.5.1 The removal of zinc from solution 155
4.5.2 The uptake of zinc into roots, rhizomes and aerial sections 157
4.6 The uptake of zinc, copper and silver by Equisetum fluviatile 160
4.7 Conclusions 163

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