Sherameti / Varma Soil Heavy Metals

1. Auflage 2010
ISBN: 978-3-642-02436-8
Verlag: Springer
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, Band 19, 492 Seiten

Reihe: Soil Biology

Human activities have dramatically changed the composition and organisation of soils. Industrial and urban wastes, agricultural application and also mining activities resulted in an increased concentration of heavy metals in soils. How plants and soil microorganisms cope with this situation and the sophisticated techniques developed for survival in contaminated soils is discussed in this volume. The topics presented include: the general role of heavy metals in biological soil systems; the relation of inorganic and organic pollutions; heavy metal, salt tolerance and combined effects with salinity; effects on abuscular mycorrhizal and on saprophytic soil fungi; heavy metal resistance by streptomycetes; trace element determination of environmental samples; the use of microbiological communities as indicators; phytostabilization of lead polluted sites by native plants; effects of soil earthworms on removal of heavy metals and the remediation of heavy metal contaminated tropical land.

Autoren/Hrsg.

Sherameti, Irena

Varma, Ajit

Inhaltsverzeichnis

1;Foreword;6
2;Preface;9
3;Contents;12
4;Contributors;14
5;Chapter 1;18
5.1;Soil: The Living Matrix;18
5.1.1;1.1 Introduction;18
5.1.2;1.2 Soil Taxonomy and Classification;19
5.1.3;1.3 Soils of the Humid Tropics and Subtropics;20
5.1.4;1.4 Chemical and Colloidal Properties;22
5.1.5;1.5 Soil Water;23
5.1.6;1.6 The Living Matrix;23
5.1.7;1.7 Soils and Plant Nutrition;25
5.1.8;1.8 Soil Organic Matter;26
5.1.9;1.9 Soil Texture;27
5.1.10;1.10 Permafrost Soils;27
5.1.11;1.11 Soil Pollution;31
5.1.12;1.12 Conclusion;34
5.2;References;34
6;Chapter 2;36
6.1;Definition of “Heavy Metals” and Their Role in Biological Systems;36
6.1.1;2.1 Introduction;36
6.1.2;2.2 The Definition of Heavy Metals in Plant Science;36
6.1.2.1;2.2.1 Metals;36
6.1.2.2;2.2.2 Heavy Metals;38
6.1.2.3;2.2.3 Lewis Acid Strength and Ionic Indices;38
6.1.2.4;2.2.4 Toxicity;39
6.1.3;2.3 Toxicity of Heavy Metals in Biological Systems;41
6.1.3.1;2.3.1 General Effects;42
6.1.3.2;2.3.2 Primary Targets of Heavy Metal Toxicity;42
6.1.3.3;2.3.3 Water Relations;43
6.1.3.4;2.3.4 Formation of Reactive Oxygen Species;43
6.1.3.5;2.3.5 Photosynthesis;44
6.1.3.6;2.3.6 Mitochondrial Respiration;45
6.1.4;2.4 Conclusion;45
6.2;References;46
7;Chapter 3;47
7.1;Soil Microbial Diversity in Relation to Heavy Metals;47
7.1.1;3.1 Introduction;47
7.1.2;3.2 Microbial Diversity in Soils;49
7.1.2.1;3.2.1 Types of Microorganisms;50
7.1.2.1.1;3.2.1.1 Eubacteria;51
7.1.2.1.2;3.2.1.2 Actinomycetes;53
7.1.2.1.3;3.2.1.3 Archaebacteria;54
7.1.2.1.3.1;Methanogens;54
7.1.2.1.3.2;Halophiles;55
7.1.2.1.3.3;Thermoacidophiles;55
7.1.2.1.4;3.2.1.4 Fungi;56
7.1.2.1.5;3.2.1.5 Rhizospheric Microorganisms;57
7.1.2.1.6;3.2.1.6 Rhizoplane Microorganisms;58
7.1.2.1.7;3.2.1.7 Mycorrhiza;58
7.1.2.1.7.1;Types of Mycorrhizae;58
7.1.2.1.7.1.1;Piriformospora indica;61
7.1.2.1.7.2;Algae;61
7.1.3;3.3 Soil Pollution;62
7.1.3.1;3.3.1 Heavy Metals;64
7.1.3.2;3.3.2 Soil Pollution by Heavy Metals: A Highly Complex Disruption of Ecological Equilibrium;65
7.1.3.3;3.3.3 Rhizospheric Microorganisms;66
7.1.3.4;3.3.4 Bioavailability of Toxic Heavy Metals;67
7.1.4;3.4 Bacteria and Heavy Metals;68
7.1.4.1;3.4.1 Impact of Heavy Metals on Bacterial Community Structure and Microbial Processes;68
7.1.4.2;3.4.2 Influence of Soil Rhizobacteria on Heavy Metal Bioavailability;68
7.1.4.3;3.4.3 Heavy Metal Resistance Systems in Bacteria;69
7.1.4.4;3.4.4 Heavy Metal–Bacteria Interactions;69
7.1.5;3.5 Fungi and Heavy Metals;70
7.1.5.1;3.5.1 Role of Mycorrhizae in Heavy Metal Speciation;72
7.1.6;3.6 Conclusion;73
7.2;References;73
8;Chapter 4;80
8.1;Uptake and Effect of Heavy Metals on the Plant Detoxification Cascade in the Presence and Absence of Organic Pollutants;80
8.1.1;4.1 Introduction: Which Metals are “Heavy”?;80
8.1.2;4.2 Classification of Metals;80
8.1.3;4.3 Metal Toxicity;81
8.1.4;4.4 Mixed Pollution with Organic Pollutants;81
8.1.5;4.5 Sources of Environmental Contamination;82
8.1.6;4.6 Uptake Mechanisms for Metal and Organic Xenobiotics in Plants;83
8.1.6.1;4.6.1 Factors that Influence Metal Uptake;83
8.1.6.2;4.6.2 Metal Transport in Shoots;86
8.1.7;4.7 What Causes Oxidative Stress?;86
8.1.7.1;4.7.1 Oxidative Damage to Lipids;87
8.1.7.2;4.7.2 Oxidative Damage to Proteins;88
8.1.7.3;4.7.3 Where are the Products of Activated Oxygen Formed?;88
8.1.7.4;4.7.4 Defence Mechanisms Against Oxidative Stress;90
8.1.7.4.1;4.7.4.1 Superoxide Dismutase (SOD) (EC 1.15.1.11);90
8.1.7.4.2;4.7.4.2 Catalase (1.11.1.6);91
8.1.7.4.3;4.7.4.3 Ascorbic Acid;91
8.1.7.4.4;4.7.4.4 Peroxidase (EC 1.11….);92
8.1.7.4.5;4.7.4.5 Glutathione Reductase (EC 1.6.4.2);92
8.1.7.4.6;4.7.4.6 Glutathione;92
8.1.7.4.7;4.7.4.7 Phytochelatins;93
8.1.7.4.8;4.7.4.8 Carotenoids;94
8.1.7.5;4.7.5 Other Detoxification Mechanisms in Plants;95
8.1.7.5.1;4.7.5.1 Glutathione S-Transferases;95
8.1.7.5.2;4.7.5.2 Mixed Pollution;96
8.1.8;4.8 Conclusion;97
8.2;References;97
9;Chapter 5;101
9.1;Arbuscular Mycorrhiza, Heavy Metal,and Salt Tolerance;101
9.1.1;5.1 Introduction;101
9.1.2;5.2 Heavy Metals and Their Toxicities;101
9.1.3;5.3 Specific Metallophytes and Their Potential Role in Phytoremediation;104
9.1.4;5.4 A Short Excursion into the Biology of Arbuscular Mycorrhizal Fungi;109
9.1.5;5.5 Arbuscular Mycorrhizal Fungi in Heavy Metal Soils;113
9.1.6;5.6 Biochemical and Molecular Aspects of the Heavy Metal Tolerance Conferred on Plants by AMF;117
9.1.7;5.7 Arbuscular Mycorrhizal Fungi and Salt Tolerance;119
9.1.8;5.8 Conclusion;121
9.2;References;121
10;Chapter 6;126
10.1;Quantitative Analyses of Trace Elements in Environmental Samples: Options and (Im)possibilities;126
10.1.1;6.1 Introduction;126
10.1.2;6.2 Analytical Methods for Bulk Samples;127
10.1.2.1;6.2.1 Basic Principles of X-Ray Fluorescence;127
10.1.2.2;6.2.2 Standard Energy-Dispersive X-Ray Fluorescence Analysis;129
10.1.2.3;6.2.3 Total Reflection X-Ray Fluorescence;132
10.1.3;6.3 Element Localization Analyses;134
10.1.3.1;6.3.1 Micro-Proton-Induced X-Ray Emission Spectroscopy;134
10.1.3.2;6.3.2 Sample Preparation;135
10.1.3.3;6.3.3 Data Processing and Evaluation;136
10.1.3.4;6.3.4 Instrumentation and Examples;136
10.1.4;6.4 Element Complexation Analyses;137
10.1.4.1;6.4.1 X-Ray Absorption Spectroscopy;137
10.1.4.2;6.4.2 X-Ray Absorption Near-Edge Structure;141
10.1.4.3;6.4.3 Extended X-Ray Absorption Fine Structure;142
10.1.4.4;6.4.4 EXAFS and XANES in Practice;146
10.1.5;6.5 Conclusions;148
10.2;References;149
11;Chapter 7;152
11.1;At the Crossroads of Metal Hyperaccumulation and Glucosinolates: Is There Anything Out There?;152
11.1.1;7.1 Introduction;152
11.1.2;7.2 Metal-Induced Responses in Plants;153
11.1.3;7.3 The Evolution of Metal Hyperaccumulation;155
11.1.4;7.4 Glucosinolates: Metabolism and Occurrence in Vascular Plants;156
11.1.5;7.5 Interactions of Metals and Glucosinolates;159
11.1.5.1;7.5.1 Cadmium;163
11.1.5.2;7.5.2 Zinc;164
11.1.5.3;7.5.3 Nickel;165
11.1.5.4;7.5.4 Selenium;165
11.1.6;7.6 Mycorrhizal Colonisation in Glucosinolate-Containing Plants;166
11.1.7;7.7 Conclusion;168
11.2;References;168
12;Chapter 8;175
12.1;Plants Under Heavy Metal Stress in Saline Environments;175
12.1.1;8.1 Introduction;175
12.1.2;8.2 Combined Effects of HMs and Salinity on Plants from Various Ecological Groups;176
12.1.2.1;8.2.1 Halophytes of Salt Marshes;176
12.1.2.2;8.2.2 Other Halophytes;178
12.1.2.3;8.2.3 Crop Plants;182
12.1.2.3.1;8.2.3.1 Monocotyledonous Crops;182
12.1.2.3.2;8.2.3.2 Dicotyledonous Crops;184
12.1.2.4;8.2.4 Water Macrophytes;185
12.1.3;8.3 Mechanisms of the NaCl–HM Interaction;187
12.1.4;8.4 Conclusion;193
12.2;References;193
13;Chapter 9;196
13.1;Utilizing Microbial Community Structure and Function to Evaluate the Health of Heavy Metal Polluted Soils;196
13.1.1;9.1 Introduction;196
13.1.2;9.2 Microbial Properties as Indicators of Soil Health;198
13.1.3;9.3 Microbial Function and Community Structure;199
13.1.4;9.4 Microbial Biomass as an Indicator;201
13.1.4.1;9.4.1 Culture-Based and Direct Methods;201
13.1.4.2;9.4.2 Indirect Methods;201
13.1.5;9.5 Microbial Function;203
13.1.5.1;9.5.1 Carbon Mineralization: Soil Respiration;203
13.1.5.2;9.5.2 Nitrogen Mineralization, Nitrification, Denitrification, and N2 Fixation;205
13.1.5.2.1;9.5.2.1 Nitrogen Mineralization;205
13.1.5.2.2;9.5.2.2 Nitrification;206
13.1.5.2.3;9.5.2.3 Denitrification;206
13.1.5.2.4;9.5.2.4 N2 Fixation;207
13.1.5.3;9.5.3 Enzyme Activities;207
13.1.5.4;9.5.4 Microbial DNA and Protein Synthesis;208
13.1.5.5;9.5.5 Fungal Acetate in Ergosterol Incorporation;209
13.1.6;9.6 Microbial Diversity;210
13.1.6.1;9.6.1 Membrane Lipids;211
13.1.6.2;9.6.2 Nucleic Acid Based Methods;214
13.1.6.2.1;9.6.2.1 Percentage of Guanine–Cytosine and DNA Reassociation Techniques;216
13.1.6.2.2;9.6.2.2 Denaturing and Temperature Gradient Gel Electrophoresis (DGGE/TGGE);217
13.1.6.2.3;9.6.2.3 Amplified Ribosomal DNA Restriction Analysis (ARDRA);218
13.1.6.2.4;9.6.2.4 Terminal Restriction Fragment Length Polymorphism (T-RFLP);218
13.1.6.2.5;9.6.2.5 Ribosomal Intergenic Spacer Analysis (RISA);220
13.1.6.2.6;9.6.2.6 Fluorescent In Situ Hybridization;221
13.1.7;9.7 Functional Diversity and Community-Level Physiological Profiles (CLPPs);222
13.1.8;9.8 Resilience of Microbial Function and Community Structure;223
13.1.9;9.9 Conclusions: Drawbacks and Challenges for the Future;225
13.2;References;227
14;Chapter 10;236
14.1;Streptomycete Heavy Metal Resistance: Extracellular and Intracellular Mechanisms;236
14.1.1;10.1 Introduction;236
14.1.2;10.2 Streptomycetes Are a Prominent Population in Heavy Metal Contaminated Soils;237
14.1.3;10.3 Isolation of Heavy Metal Resistant Streptomycetes;238
14.1.4;10.4 Metal Resistance Characterization and Adaptation;240
14.1.5;10.5 Chelators and Siderophores;240
14.1.6;10.6 Biomineralization;242
14.1.7;10.7 Cell Wall Adsorption;242
14.1.8;10.8 Intracellular Storage;243
14.1.9;10.9 Conclusion;244
14.2;References;245
15;Chapter 11;247
15.1;Effects of Heavy Metals on Soil Enzyme Activities;247
15.1.1;11.1 Introduction;247
15.1.2;11.2 Inhibition of Soil Enzymes;248
15.1.2.1;11.2.1 Metal Factors;249
15.1.2.1.1;11.2.1.1 Heavy Metal Element;249
15.1.2.1.2;11.2.1.2 Metal Concentration;249
15.1.2.1.3;11.2.1.3 Chemical Form of the Heavy Metal;252
15.1.2.1.4;11.2.1.4 Availability of the Heavy Metal;252
15.1.2.2;11.2.2 Enzyme Factors;253
15.1.2.2.1;11.2.2.1 Enzyme Sensitivity;253
15.1.2.2.2;11.2.2.2 Structural Inhibition of the Enzyme;254
15.1.2.2.3;11.2.2.3 Seasonal Effects of Enzymes;255
15.1.2.3;11.2.3 Soil Factors;255
15.1.2.3.1;11.2.3.1 pH;255
15.1.2.3.2;11.2.3.2 Soil Organic Matter;256
15.1.2.3.3;11.2.3.3 Clay Minerals;257
15.1.2.4;11.2.4 Plant Factors;258
15.1.2.4.1;11.2.4.1 Metal Accumulator Plants;258
15.1.2.4.2;11.2.4.2 Plant Community Effect;258
15.1.2.5;11.2.5 Special Inhibition Parameters;259
15.1.2.5.1;11.2.5.1 Ecological Dose;259
15.1.2.6;11.2.6 Understanding the Inhibition of Soil Enzymes by Heavy Metals;259
15.1.2.6.1;11.2.6.1 Combined Effects;259
15.1.2.6.1.1;Combined Effects of Two Metals;259
15.1.2.6.1.2;Combined Effects of Three Metals;261
15.1.2.6.1.3;Combined Effects of pH, Organic Matter (OM), Clay, and Four Metals;262
15.1.2.6.1.4;Combined Effects of pH, OM, Clay, Cation Exchange Capacity (CEC), and Chemical Form of Metal;262
15.1.2.6.1.5;Combined Effects of Metal, Metal Oxidation State, and Organic Matter;264
15.1.3;11.3 Conclusion;264
15.2;References;266
16;Chapter 12;273
16.1;Effect of Heavy Metals on Saprotrophic Soil Fungi;273
16.1.1;12.1 Introduction;273
16.1.2;12.2 Interactions of Fungi with Heavy Metals in the Soil Environment;274
16.1.2.1;12.2.1 Mobilization and Immobilization of Heavy Metals;274
16.1.2.2;12.2.2 Accumulation of Heavy Metals by Fungi;276
16.1.3;12.3 Effects of Heavy Metals on Fungal Physiology;277
16.1.4;12.4 Effects of Heavy Metals on Soil Fungal Communities;278
16.1.5;12.5 Metal-Induced Changes in Fungus-Related Ecosystem Processes;282
16.1.6;12.6 Conclusion;284
16.2;References;284
17;Chapter 13;290
17.1;Copper-Containing Oxidases: Occurrence in Soil Microorganisms, Properties, and Applications;290
17.1.1;13.1 Introduction;290
17.1.2;13.2 Tyrosinases;293
17.1.2.1;13.2.1 Occurrence;293
17.1.2.2;13.2.2 Relation to Melanin;293
17.1.2.3;13.2.3 Copper Sites;294
17.1.2.4;13.2.4 Streptomyces Tyrosinases;296
17.1.2.4.1;13.2.4.1 Biochemical Properties;297
17.1.2.4.2;13.2.4.2 Incorporation of Copper;297
17.1.2.4.3;13.2.4.3 Induction and Secretion;298
17.1.2.5;13.2.5 Role in Nature;298
17.1.2.6;13.2.6 Applications;300
17.1.3;13.3 Laccases;301
17.1.3.1;13.3.1 Distribution;301
17.1.3.2;13.3.2 Properties of Fungal Laccases;302
17.1.3.3;13.3.3 Reaction Mechanism;303
17.1.3.3.1;13.3.3.1 Crosslinking;303
17.1.3.3.2;13.3.3.2 Polymer Degradation;304
17.1.3.3.3;13.3.3.3 Ring Cleavage of Aromatics;304
17.1.3.4;13.3.4 Substrates and Inhibitors;304
17.1.3.5;13.3.5 Role in Nature;305
17.1.4;13.4 Applications;308
17.1.4.1;13.4.1 Treatment of Polluted Soils;308
17.1.5;13.5 Conclusion;310
17.2;References;311
18;Chapter 14;323
18.1;Biomethylation of Heavy Metals in Soil and Terrestrial Invertebrates;323
18.1.1;14.1 Introduction;323
18.1.2;14.2 Analysis of Methylated Heavy Metals;324
18.1.2.1;14.2.1 Methylation Methods;324
18.1.2.2;14.2.2 Extraction Methods;325
18.1.2.2.1;14.2.2.1 Aqueous, Acidic and Alkaline Extractions;325
18.1.2.2.2;14.2.2.2 Microwave-Assisted Extraction;325
18.1.2.2.3;14.2.2.3 Enzymatic Extraction;325
18.1.2.2.4;14.2.2.4 Solid-Phase Extraction;326
18.1.2.3;14.2.3 Separation Methods;326
18.1.2.3.1;14.2.3.1 High-Performance Liquid Chromatography;326
18.1.2.3.2;14.2.3.2 Gas Chromatography;327
18.1.2.4;14.2.4 Detection Methods;327
18.1.2.4.1;14.2.4.1 Atomic Absorbance Spectrometry;327
18.1.2.4.2;14.2.4.2 Atomic Fluorescence Spectrometry;328
18.1.2.4.3;14.2.4.3 Inductively Coupled Plasma Mass Spectrometry;328
18.1.3;14.3 Microbial Methylation of Heavy Metals;328
18.1.3.1;14.3.1 Mercury;328
18.1.3.1.1;14.3.1.1 Soil/Sediments;329
18.1.3.1.2;14.3.1.2 Sewage Sludge;330
18.1.3.1.3;14.3.1.3 Mastotermes darwinesis;330
18.1.3.1.4;14.3.1.4 Porcellio scaber;330
18.1.3.1.5;14.3.1.5 Eisenia foetida;331
18.1.3.2;14.3.2 Selenium and Arsenic;331
18.1.3.3;14.3.3 Bismuth;332
18.1.4;14.4 Conclusion;333
18.2;References;334
19;Chapter 15;337
19.1;Phytostabilization of Lead-Polluted Sites by Native Plants;337
19.1.1;15.1 Introduction;337
19.1.2;15.2 Materials and Methods;338
19.1.2.1;15.2.1 Study Area;338
19.1.2.2;15.2.2 Chemical Immobilization: Plot Experiment;338
19.1.2.3;15.2.3 Description of the Sampling and Analytical Methods Used;339
19.1.2.3.1;15.2.3.1 First Stages of Phytostabilization;340
19.1.3;15.3 Salient Observations;340
19.1.3.1;15.3.1 Chemical Immobilization: Plot Experiment;340
19.1.3.2;15.3.2 First Stages of Phytostabilization;342
19.1.4;15.4 Conclusion;343
19.2;References;344
20;Chapter 16;346
20.1;Impact of Heavy Metals on Sugarcane;346
20.1.1;16.1 Introduction: Extent of Sugarcane Cultivation and Cane Yield Potential;346
20.1.1.1;16.1.1 Heavy Metal Contents in Different Materials used in Agriculture;347
20.1.1.2;16.1.2 Sufficient and Phytotoxic Levels of Heavy Metals in Plants;347
20.1.2;16.2 Sources of Metal Contamination of Sugarcane;348
20.1.2.1;16.2.1 Phosphatic Fertilizers;348
20.1.2.2;16.2.2 Sewage Sludge;349
20.1.2.3;16.2.3 Industrial Residue (Vinasse);349
20.1.2.4;16.2.4 Sugar Mill By-Products;350
20.1.2.5;16.2.5 Tannery Effluents;350
20.1.2.6;16.2.6 Pig Effluents;351
20.1.2.7;16.2.7 Swine Lagoon Effluents;351
20.1.2.8;16.2.8 Spent Wash/Effluents;352
20.1.2.9;16.2.9 Fungicides;353
20.1.2.10;16.2.10 Metal-Polluted Landfills;354
20.1.2.11;16.2.11 Use of Brackish Water for Irrigation;354
20.1.2.12;16.2.12 Soil Polluted by Industry;355
20.1.3;16.3 Effects of Different Sources of Heavy Metals on Soil and Sugarcane;355
20.1.4;16.4 Critical Limits for Heavy Metals in Soil;356
20.1.4.1;16.4.1 Effect-Based Steady-State Critical Loads: CLeffb(M);357
20.1.4.2;16.4.2 Standstill Critical Loads:.CLstst(M);357
20.1.5;16.5 Heavy Metal Contents in Soils, Sugarcane Plants, Juice, Sugar, and Jaggery;358
20.1.5.1;16.5.1 In Soils;358
20.1.5.2;16.5.2 In the Sugarcane Plant;358
20.1.5.3;16.5.3 In Cane Juice;360
20.1.5.4;16.5.4 In Sugar;360
20.1.5.5;16.5.5 In Jaggery;361
20.1.6;16.6 Impact of Heavy Metals on Sugarcane Physiological Function;361
20.1.6.1;16.6.1 Nickel;361
20.1.6.2;16.6.2 Chromium;362
20.1.6.3;16.6.3 Cadmium;364
20.1.6.4;16.6.4 Aluminum;365
20.1.6.5;16.6.5 Iron;365
20.1.6.6;16.6.6 Copper;366
20.1.6.7;16.6.7 Zinc;366
20.1.6.8;16.6.8 Lead;368
20.1.6.9;16.6.9 Mercury;368
20.1.7;16.7 Remedial Measures for Heavy Metal Pollution;369
20.1.7.1;16.7.1 Use of Sugarcane Bagasse Pith for Heavy Metal Removal;370
20.1.7.2;16.7.2 Sugarcane: A Phytoremediator;371
20.1.8;16.8 Conclusion;371
20.2;References;372
21;Chapter 17;375
21.1;Effects of Earthworms on the Availability and Removal of Heavy Metals in Soil;375
21.1.1;17.1 Introduction;375
21.1.2;17.2 Biology of Earthworms;376
21.1.2.1;17.2.1 Ecological Considerations;376
21.1.2.2;17.2.2 Factors Effecting Earthworm Distribution and Activity in the Soil;377
21.1.2.3;17.2.3 Digestion System of the Earthworm;380
21.1.2.4;17.2.4 Earthworm Excrement;380
21.1.2.5;17.2.5 Effects of Earthworms on the Soil;381
21.1.3;17.3 The Relationship Between Heavy Metals and Earthworms;382
21.1.3.1;17.3.1 Heavy Metal Accumulation by Earthworms;383
21.1.3.2;17.3.2 Effects of Earthworms on Heavy Metal Availability in the Soil;385
21.1.4;17.4 Conclusion;388
21.2;References;388
22;Chapter 18;395
22.1;Phytoremediation of Heavy Metal Contaminated Soils;395
22.1.1;18.1 Introduction;395
22.1.2;18.2 Heavy Metals;396
22.1.2.1;18.2.1 Sources of Heavy Metal Contamination in Soil;396
22.1.2.2;18.2.2 Heavy Metal Contamination in the Food Chain;397
22.1.3;18.3 Remediation of Heavy Metal Contaminated Soil;402
22.1.3.1;18.3.1 Phytoremediation;403
22.1.3.1.1;18.3.1.1 Hyperaccumulators: Phytoextraction of Heavy Metals;405
22.1.3.1.1.1;Zinc;406
22.1.3.1.1.2;Copper;406
22.1.3.1.1.3;Nickel;408
22.1.3.1.1.4;Lead;408
22.1.3.1.1.5;Cadmium;409
22.1.3.1.1.6;Chromium;410
22.1.3.1.1.7;Selenium;411
22.1.3.1.1.8;Arsenic;412
22.1.3.1.2;18.3.1.2 Changes in Metal Concentrations in Soil;413
22.1.3.1.3;18.3.1.3 Optimization of Metal Phytoextraction;415
22.1.3.1.3.1;Plant Selection and Genetically Engineered Plants;415
22.1.3.1.3.2;Soil Fertilization;418
22.1.3.1.3.3;Enhancement of Metal Bioavailability;419
22.1.3.1.3.3.1;Chemically Enhanced Phytoextraction;420
22.1.3.1.3.3.2;Microbially Enhanced Phytoextraction;422
22.1.3.1.4;18.3.1.4 Disposal of Contaminated Plant Residues;423
22.1.3.1.5;18.3.1.5 Making Phytoremediation More Efficient;425
22.1.3.1.6;18.3.1.6 Prospects and Potential of Phytoremediation;425
22.1.3.1.7;18.3.1.7 Future Opportunities;426
22.1.4;18.4 Conclusion;426
22.2;References;427
23;Chapter 19;436
23.1;Remediation of Heavy Metal Contaminated Tropical Land;436
23.1.1;19.1 Introduction: What are Heavy Metals?;436
23.1.2;19.2 Contamination of Land by Heavy Metals;436
23.1.3;19.3 Mobility of Metal Contaminants in Tropical Soil;438
23.1.3.1;19.3.1 Tropical Zone Ecology;438
23.1.3.2;19.3.2 Tropical Soil;439
23.1.3.3;19.3.3 Biodiversity of Tropical Land;440
23.1.3.4;19.3.4 Mobility of Heavy Metals in Tropical Land;440
23.1.4;19.4 Remediation of Heavy Metal Contaminated Tropical Land;442
23.1.4.1;19.4.1 Physicochemical Remediation;443
23.1.4.2;19.4.2 Bioremediation of Heavy Metals;444
23.1.4.2.1;19.4.2.1 In Situ Bioremediation;444
23.1.4.2.2;19.4.2.2 Composting;444
23.1.4.2.3;19.4.2.3 Bioventing;446
23.1.4.2.4;19.4.2.4 Bioaugmentation;447
23.1.4.2.5;19.4.2.5 Biostimulation;447
23.1.4.2.6;19.4.2.6 Ex Situ Bioremediation;447
23.1.4.2.6.1;Slurry-Phase Bioremediation;447
23.1.4.2.6.2;Solid-Phase Bioremediation;448
23.1.4.2.6.3;Landfarming;449
23.1.4.2.6.4;Soil Biopiles;449
23.1.5;19.5 Mechanism of the Remediation of Heavy Metal Contaminated Soil Using Microbes;450
23.1.5.1;19.5.1 Intracellular Accumulation;451
23.1.5.2;19.5.2 Cell Wall Associated Metal Interactions;452
23.1.5.3;19.5.3 Siderophores;452
23.1.5.4;19.5.4 Extracellular Mobilization/Immobilization of Metals by Bacterial Metabolites;453
23.1.5.5;19.5.5 Extracellular Polymer–Metal Interactions;453
23.1.5.6;19.5.6 Transformation and Volatilization of Metals;454
23.1.6;19.6 Enzymatic Transformation of Metals;455
23.1.7;19.7 Chemical Processes Involved in the Bioremediation of Heavy Metal Contaminated Soils;456
23.1.7.1;19.7.1 Factors Affecting Biodegradation;457
23.1.7.1.1;19.7.1.1 Soil water;457
23.1.7.1.2;19.7.1.2 Redox potential;457
23.1.7.1.3;19.7.1.3 Soil pH;457
23.1.7.1.4;19.7.1.4 Soil temperature;457
23.1.7.2;19.7.2 Limitations of Bioremediation;458
23.1.8;19.8 Genetic Aspects of Heavy Metal Resistance;458
23.1.8.1;19.8.1 In Bacteria;459
23.1.8.2;19.8.2 In Fungi;459
23.1.9;19.9 Phytoremediation of Heavy Metals;460
23.1.9.1;19.9.1 Ex Situ and In Situ Methods of Phytoremediation;460
23.1.9.1.1;19.9.1.1 Ex Situ Methods;460
23.1.9.1.2;19.9.1.2 In Situ Methods;460
23.1.9.1.2.1;Rhizofiltration;461
23.1.9.1.2.2;Phytostabilization;462
23.1.9.1.2.3;Phytoextraction;462
23.1.9.2;19.9.2 Mechanism of Phytoextraction;463
23.1.10;19.10 Types of Phytoextraction;465
23.1.10.1;19.10.1 Natural Phytoextraction;465
23.1.10.2;19.10.2 Induced Phytoextraction or Chelate-Assisted Phytoextraction;466
23.1.10.3;19.10.3 Limitations of Phytoextraction;466
23.1.10.4;19.10.4 Phytovolatilization;467
23.1.10.5;19.10.5 Phytodegradation;467
23.1.10.6;19.10.6 Rhizodegradation;468
23.1.10.7;19.10.7 Plant Growth on Heavy Metal Contaminated Soils;468
23.1.10.8;19.10.8 Metal Excluders;468
23.1.10.9;19.10.9 Metal Indicators;468
23.1.10.10;19.10.10 Metal Accumulator;468
23.1.10.11;19.10.11 Utilization of Phytoremediation By-Products;469
23.1.11;19.11 Genetic Engineering to Improve Phytoremediation;471
23.1.12;19.12 Future Prospects for Phytoremediation;474
23.1.13;19.13 Conclusion;474
23.2;References;476
24;Index;483