Environmental impact of mine drainage and its treatment on aquatic communities

357 Pages·2010·6.12 MB·English

by  Auladell Mestre, Montserrat

Environmental impact of mine
drainage and its treatment on aquatic
communities

by

Montserrat Auladell Mestre

A thesis submitted to the University of Birmingham for the degree of DOCTOR OF
PHILOSOPHY

School of Geography, Earth and Environmental Sciences
University of Birmingham
October 2009
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ABSTRACT
An ecological and chemical analysis of eight Welsh streams impacted by mine drainage
is used to discern the effects of water and sediment related variables in the impact of
mine pollution on freshwater macroinvertebrate communities. The implications of this
are to be considered for improving mine water remediation techniques and work towards
the achievement of the environmental objectives set by the EU Water Framework
Directive (WFD).
Streams impacted by coal and metal mine drainage present a clear ecological impact in
response to water and sediment related variables, demonstrating that both sediment and
water are key aspects in mine drainage pollution of freshwater ecosystems. However, the
WFD does not include metal concentration guidelines for sediments, neither has the UK
set mandatory standards for them, and sediments are not currently being routinely
monitored or remediated in the UK.
To achieve the environmental objectives set by the WFD, the Coal Authority and the
Environment Agency are constructing several engineered wetlands in the UK to treat
mine drainage. One of these constructed engineered wetlands was seen to successfully
remediate mine water removing trace metals and suspended solids and increasing pH and
dissolved oxygen. However, the remediation scheme seemed to fail to improve the
electrolyte status of the water and stream sediment quality. As a result, the benthic
community in the receiving stream appeared to have a poor recovery.
Als meus pares
(To my parents)
Acknowledgements
For the duration of this Ph.D research I have been indebted to many people for their
advice, help and support.
Primarily I should like to thank my supervisors at the University of Birmingham: Dr.
Lesley Batty and Dr. Jonathan Sadler for their constant support and guidance in the
successful completion of this research. I also owe my thanks to the Environment Agency
and the Coal Authority for funding this research and for their advice in the selection of
the study sties.
Whilst undertaking field research, invaluable assistance was provided by Jessica Frame,
Sarah Henshall and Richard Johnson, to whom I must express my gratitude. Thanks must
also be extended to the landowners who allowed access across their land to the sampled
rivers. In the laboratory, Andrew Moss, who has overseen all the Chironomidae
identifications undertaken in this research, has been a constant source of help and support
throughout the duration of this Ph.D. Steve Brooks has provided invaluable assistance in
the identification of some chironomid specimens.
I am indebted to the support given to me by my family, not just throughout the duration
of this Ph.D, but throughout the whole of my academic career. My thanks go also to my
nieces and nephew for helping me maintain prospective on life. Many thanks to Chris and
Mike for making me feel at home in the edge of the Yorkshire Wolds. I am also deeply
indebted to Peter for his unconditional support and encouragement.
TABLE OF CONTENTS
1 INTRODUCTION………………………………………………………………...1
1.1 Introduction……………………………………………………………......1
1.2 The European Union Water Framework Directive………………………..2
1.3 The role of sediment in mine pollution and the WFD…………………….6
1.4 Aims and objectives……………………………………………………….8
1.5 Thesis structure…………………………………………………………..12
2 METHODOLOGY………………………………………………………………15
2.1 Site description…………………………………………………………...15
2.1.1 Climate at the study sites………………………………………...15
2.1.2 Streams impacted by abandoned coal mines…………………….16
2.1.3 Streams impacted by abandoned metal mines…………………...28
2.2 Water sampling and analysis………………………………………….....39
2.2.1 Field measurements……………………………………………...39
2.2.2 Suspended solids…………………………………………………40
2.2.3 Major ion analysis: Dionex and ICP-MS analysis……………….41
2.2.3.1 Dionex – Ion chromatography…………………………...41
2.2.3.2 Inductively Coupled Plasma Mass Spectrometry..............47
2.3 Sediment sampling and analysis…………………………………………44
2.3.1 Trace metal analysis: Atomic Absorption Spectrophotometry…..45
2.4 Macroinvertebrate sampling and identification………………………….46
2.4.1 Macroinvertebrate sampling……………………………………..46
2.4.2 Macroinvertebrate identifications………………………………..46
2.5 Statistics………………………………………………………………….47
2.5.1 Upstream and downstream comparisons………………………...47
2.5.2 Univariate statistics using Brodgar………………………………48
2.5.2.1 Data exploration………………………………………….48
2.5.2.2 Generalised Additive Modelling…………………………50
2.5.3 Multivariate statistics using CANOCO………………….50
3 CHEMSITRY OF STREAMS IMPACTED BY MINE DRAINAGE…………..54
3.1 Introduction to mine drainage hydrochemistry………………...………..54
3.1.1 Water and sediment pollution by coal mine drainage……………55
3.1.2 Water and sediment pollution by metal mine drainage………….60
3.1.3 Aims and objectives……………………………………………...64
3.2 Methodology……………………………………………………………..66
3.2.1 Characterisation of stream chemistry…………………………….67
3.2.2 Ash Free Dry Mass analysis……………………………………..67
3.2.3 PHREEQC……………………………………………………….68
3.2.4 Statistical analysis………………………………………………..69
3.3 Results……………………………………………………………………70
3.3.1 Water and sediment chemistry in coal mine impacted streams…70
3.3.2 Water and sediment chemistry in metal mine impacted
streams..………………………………………………………….80
3.4 Discussion………………………………………………………………..91
3.4.1 Coal mine pollution………………………………………………91
3.4.1.1 Water and sediment chemistry…………………………...91
3.4.1.2 Water-sediment interphase……………………………….94
3.4.2 Metal mine pollution……………………………………………..96
3.4.2.1 Water and sediment pollution……………………………96
3.4.2.2 Water-sediment interphase……………………………….99
3.5 Conclusion……………………………………………………………...102
4 ASSEMBLAGE STRUCTURE IN STREAMS IMPACTED BY MINE
DRAINAGE…………………………………………………………………………….104
4.1 Introduction……………………………………………………………..104
4.1.1 The impact of water pollution upon freshwater communities….105
4.1.1.1 pH effect on organisms…………………………………105
4.1.1.2 Trace metal effect on organisms………………………..107
4.1.2 The impact of polluted sediments upon freshwater
communities…………………………………………………….109
4.2 Aims and objectives…………………………………………………….112
4.3 Methodology……………………………………………………………113
4.3.1 Species data……………………………………………………..113
4.3.2 Environmental data……………………………………………..114
4.3.3 Statistical analysis………………………………………………118
4.3.3.1 Ecosystem structure paired analysis……………………118
4.3.3.2 Multivariate statistics…………………………………...118
4.4 Results…………………………………………………………………..120
4.4.1 Coal mine impacted streams……………………………………120
4.4.1.1 Changes in assemblage structure downstream from coal
mine drainage discharge………………………………..120
4.4.1.2 Relationship between ecology and coal mine drainage
physico-chemical characteristics…..…………………...121
4.4.1.2.1 Autumn 2006 and winter 2007…………….…122
4.4.1.2.2 Summer 2006 and Spring 2007……..………...125
4.4.2 Metal mine impacted streams…………………………………..128
4.4.2.1 Changes in community structure downstream from metal
mine drainage discharge………………………………..128
4.4.2.2 Relationship between assemblage structure and metal mine
drainage chemical characteristics….…………………...129
4.5 Discussion………………………………………………………………132
4.5.1 Ecological structure of coal mine drainage impacted streams.…132
4.5.2 Ecological structure of metal mine drainage impacted streams...137
4.6 Conclusion……………………………………………………………...142