List of Contributors xvi Preface xxiv 1 An Introduction to Arsenic: Sources, Occurrence, and Speciation 1 Jabbar Khan, Govind Gupta, Riddhi Shrivastava, and Naveen Kumar Singh 1.1 Introduction 1 1.2 Status of Arsenic Contamination Around the World 2 1.3 Arsenic in the Aquatic and Terrestrial Environment 3 1.4 Absolute Bioavailability and Bioaccessibility of As in Plants and Agronomic Systems 4 1.5 Factors Determining Arsenic Speciation and Bioavailability in Soil 4 1.5.1 Effect of Redox Potential (Eh) and pH 4 1.5.2 Interactions with Al, Fe, and Mn Oxides and Oxyhydroxides 5 1.5.3 Interactions with P, Si, and Other Elements’ Concentration in the Soil 6 1.5.4 Interactions with Organic Matter 7 1.5.5 Clay Minerals and Other Factors 8 1.6 Arsenic Speciation in Plants 8 1.6.1 Methods of Determination of As and As Species in Plants 8 1.6.2 Uptake and Efflux Mechanism of Arsenate and Arsenite Species 9 1.6.3 Uptake and Efflux Mechanism of Methylated Arsenic Species 11 1.6.4 Arsenic and Rhizosphere Interaction (Mycorrhizal Fungi, Rhizofiltration) 12 1.7 Thiolated Arsenic and Bioavailability of Thiolated As Species in Plants and Terrestrial Environments 13 1.8 Conclusion 13 Acknowledgments 14 References 14 2 Chemistry and Occurrence of Arsenic in Water 25 Marta Irene Litter 2.1 Chemical Properties of Arsenic 25 2.2 Worldwide Occurrence of Arsenic 26 2.3 Arsenic Occurrence in Natural Media 29 2.4 Arsenic Mobilization in Natural Media 31 2.5 Biological Methylation of Arsenic in Organisms 35 2.6 Anthropogenic Arsenic Contamination 39 2.7 Toxicity of Arsenic in Waters 40 2.8 Conclusion 41 References 42 3 Arsenic Transport and Metabolism in Plants 49 Gerald Zvobgo 3.1 Introduction 49 3.2 Arsenite Influx and Efflux 50 3.3 Arsenate Influx and Efflux 51 3.3.1 Arsenate and Phosphate Chemistry 51 3.3.2 Effects of As and P in Plants 53 3.3.3 Nature of Phosphate Transporters in Plants 53 3.3.4 Variations in PHT upon As and P Addition 54 3.3.5 Gene Manipulation of PHTs and PHT Related TFs 55 3.4 Transportation of Methylated As Species 56 3.5 Arsenic Metabolism in Plants 56 3.6 Conclusion 57 References 58 4 Arsenic Induced Responses in Plants: Impacts on Different Plant Groups, from Cyanobacteria to Higher Plants 64 Kavita Ghosal, Moumita Chatterjee, Sharmistha Ganguly, Subhamita Sen Niyogi, and Dwaipayan Sinha 4.1 Introduction 64 4.2 Responses of Arsenic on Various Plant Groups 66 4.3 Arsenic Response in Cyanophycean Algae 67 4.4 Responses on Other Groups of Algae (Chlorophyceae, Phaeophyceae, Rhodophyceae, Diatoms, Xanthophyceae, Charophyceae, etc.) 69 4.4.1 Chlorophyceae 69 4.4.2 Phaeophyceae 70 4.4.3 Rhodophyceae 70 4.4.4 Diatoms 70 4.5 Responses on Moss 71 4.6 Arsenic Response on Pteridophyte 72 4.7 Responses in Angiosperms 73 4.8 Perception of Arsenic Stress by Plants and Triggering of Signaling Cascades 76 4.9 Mechanistic Aspects of Responses Related to Arsenic (Effect on ATP Synthesis, Photosynthesis, DNA, Protein, Cell Membrane, Carbohydrate, and Lipid Metabolism) 79 4.9.1 Effect of Arsenic on ATP Synthesis 79 4.9.2 Arsenic’s Effect on Photosynthesis 79 4.9.3 Effect of Arsenic on Cell Membrane 80 4.9.4 Arsenic Induced Oxidative Stress 80 4.9.5 Effect of Arsenic on Carbohydrate Metabolism 80 4.9.6 Effect of Arsenic on Lipid Metabolism 81 4.9.7 Effect of Arsenic on Protein 81 4.9.8 Effect of Arsenic on DNA 82 4.10 Future Prospects and Conclusion 82 References 83 5 Arsenic-Induced Responses in Plants: Impacts on Morphological, Anatomical, and Other Quantitative and Qualitative Characters 99 Sumaya Farooq, Simranjeet Singh, Vijay Kumar, Daljeet Singh Dhanjal, Praveen C. Ramamurthy, and Joginder Singh 5.1 Introduction 99 5.2 Impact of Arsenic on the Morphological Characters of Plants 100 5.3 Impact of Arsenic on the Anatomical Characters of Plants 101 5.4 Effect of As on stem Anatomy of Plants 102 5.4.1 Effect of Arsenic on Anatomy of Plants Roots 103 5.5 Impacts of Arsenic on Quantitative Characters of Plants 103 5.5.1 Root Plasmolysis 103 5.5.2 Cell Division 103 5.5.3 Biomass 104 5.5.4 Energy Flow 104 5.5.5 Photosynthetic Pigments 104 5.6 Impact of Arsenic on the Qualitative Characters of Plants 105 5.6.1 Cellular Membrane Damage 105 5.6.2 Leaf Reflectance 105 5.6.3 Water Loss 106 5.7 Conclusion 106 References 107 6 Arsenic-Induced Responses in Plants: Impacts on Biochemical Processes 112 Sanjay Kumar, Varsha Rani, Simranjeet Singh, Dhriti Kapoor, Daljeet Singh Dhanjal, Ankita Thakur, Mamta Pujari, Praveen C. Ramamurthy, and Joginder Singh 6.1 Introduction 112 6.2 Arsenic Effect on Biochemical Process in Plants 113 6.3 Oxidative Stress on the Arsenic-Induced Plant 114 6.4 Carbohydrate Metabolism in the Arsenic-Induced Plant 116 6.5 Lipid Metabolism in the Arsenic-Induced Plant 118 6.6 Protein Metabolism in the Arsenic-Induced Plant 120 6.7 Conclusion 121 References 122 7 Photosynthetic Responses of Two Salt-Tolerant Plants, Tamarix gallica and Arthrocnemum indicum Against Arsenic Stress: A Case Study 129 Dhouha Belhaj Sghaier, Sílvia Pedro, Bernardo Duarte, Isabel Caçador, and Noomene Sleimi 7.1 Introduction 129 7.2 Metal Uptake 131 7.3 Impact of Arsenic on Photosynthetic Pigments 133 7.4 Effect of Arsenic on Photosynthetic Apparatus 137 7.5 Conclusion 147 References 148 8 Genomic and Transcriptional Regulation During Arsenic Stress 153 Madhu Tiwari, Maria Kidwai, Neelam Gautam, and Debasis Chakrabarty 8.1 Introduction 153 8.2 Study of Differentially Regulated Genes During Arsenic Stress in Plants 154 8.3 Genetic Study of Arsenic-Responsive Genes in Plants 158 8.3.1 Genetic Study of Transporters Involved in Arsenic Uptake and Translocation 158 8.3.1.1 Transporters Involved in Arsenate Uptake in Plants 158 8.3.1.2 Transporters for AsIII Uptake in Plants 160 8.3.1.3 Genes Involved in Intracellular AsV to AsIII Conversion in Plants 160 8.3.1.4 Transporters for As Translocation 162 8.3.1.5 Genetic Study of As Detoxification Genes in Plants 163 8.4 Concluding Remarks and Future Prospects 165 Acknowledgments 166 References 166 9 Proteomic Regulation During Arsenic Stress 173 Naina Marwa, Sunil Kumar Gupta, Gauri Saxena, Vivek Pandey, and Nandita Singh 9.1 Introduction 173 9.1.1 Proteins in Antioxidative Defense Strategies 174 9.2 Molecular Chaperones in Response to Arsenic Stress 175 9.3 Participation of Protein in CO 2 Assimilation and Photosynthetic Activity 177 9.4 Pathogen-Responsive Proteins (PR) in Response to Arsenic Stress 178 9.5 Participation of Proteins in Energy Metabolism 178 9.6 Possible Pan-interactomics 179 9.7 Conclusion 180 References 180 10 Metabolomic Regulation During the Arsenic Stress 185 Pooja Sharma, Anuj Kumar Tiwari, Neeraj Kumar Dubey, Charu Chaturvedi, Amit Prakash Raghuvanshi, and Surendra Pratap Singh 10.1 Introduction 185 10.2 Arsenic Uptake/Translocation in Plants 187 10.3 Arsenic Removal Efficiency in Plants 188 10.4 Toxicity of Arsenic on Plants Metabolism 189 10.5 Metabolome Regulation and Plants Tolerance 190 10.6 Concluding Remarks 191 Acknowledgments 192 References 192 11 Role of Phytohormones in Regulating Arsenic-Induced Toxicity in Plants 198 Ummey Aymen, Marya Khan, Rachana Singh, Parul Parihar, and Neha Pandey 11.1 Arsenic and Its Source 198 11.2 Uptake and Transport of Arsenic Within Plants 200 11.3 Mechanism of Arsenic Efflux by Plant Roots 202 11.4 Impact of Arsenic on Metabolism and its Toxicity in Plants 203 11.5 Phytohormones, Their Role and Interaction with Heavy Metals 205 11.6 Mechanism of Detoxification of Heavy Metals with Special Emphasis on Arsenic by Phytohormones 207 11.7 Exogenous Application of Phytohormones over Detoxification 209 11.8 Conclusion 210 References 210 12 Influence of Some Chemicals in Mitigating Arsenic-Induced Toxicity in Plants 223 Palin Sil and Asok K. Biswas 12.1 Introduction 223 12.2 Role of Phosphorus 227 12.3 Role of Nitric Oxide 229 12.4 Role of Hydrogen Sulfide 230 12.5 Role of Calcium 230 12.6 Role of Proline 231 12.7 Role of Phytohormones 232 12.8 Role of Selenium 235 12.9 Role of Silicon 236 12.10 Conclusion 238 Author Contributions 240 Acknowledgments 240 References 240 13 Strategies to Reduce the Arsenic Contamination in the Soil–Plant System 249 Mohammad Mehdizadeh, Waseem Mushtaq, Shahida Anusha Siddiqui, Samina Aslam, Duraid K.A. AL-Taey, Koko Tampubolon, Emad Jafarzadeh, and Anahita Omidi 13.1 Introduction 249 13.2 Arsenic 250 13.3 Arsenic Use in Agricultural Soils 252 13.4 Arsenic Fate in Soil 252 13.5 Toxicity of Arsenic on Humans, Animals and Plants 253 13.6 Strategies to Reduce the Arsenic Contamination in the Soil–Plant System 254 13.6.1 Agricultural Management for Detoxification and Mitigation of Arsenic 254 13.6.2 Biotechnological Method 255 13.6.3 Bioremediation 256 13.6.3.1 Phytoremediation 256 13.6.3.2 Microbial and Fungal Remediation 256 13.6.3.3 Addition of Fertilizers to Soils 257 13.6.3.4 Other Methods 257 13.7 Conclusions 257 References 259 14 Arsenic Removal by Phytoremediation Techniques 267 Zahra Souri, Hamidreza Sharifan, Letúzia Maria de Oliveira, and Lucy Ngatia 14.1 Arsenic Presence in the Environment 267 14.2 Arsenic Contamination and its Effects on Human Health 269 14.3 Arsenic Toxicity in Plants 270 14.4 Arsenic Attenuation by Phytoremediation Technology 273 14.5 Phytoextraction 274 14.6 Arsenic Hyperaccumulation by Plants 274 14.7 Phytostabilization 275 14.8 Phytovolatilization 275 14.9 Rhizofiltration 276 14.10 Novel Approaches of Phytoremediation Technology 276 14.10.1 Using Nanotechnology 276 14.10.2 Nanoparticles in Soil 276 14.10.3 Foliar Application of Nanoparticles 277 14.10.4 Intercrops and Rotation Cultivation 279 14.10.5 Irrigation Regime Management 279 14.10.6 Soil Oxyanions Management 279 References 280 15 Arsenic Removal by Electrocoagulation 287 Aysegul Yagmur Goren and Mehmet Kobya 15.1 Introduction 287 15.2 Arsenic Contamination in Natural Waters 287 15.3 Advantages and Disadvantages of Main Arsenic Removal Technologies 290 15.4 As Removal Mechanism with EC 293 15.5 Operating Parameters Affecting Arsenic Removal Through EC 295 15.6 Electrode Shape and Material 295 15.7 Solution pH 301 15.8 Effect of Applied Current 302 15.9 Optimization of EC Arsenic Removal Process 304 15.10 Cost of EC Arsenic Removal Method 305 15.11 Merits and Demerits 306 15.12 Conclusions 307 References 308 16 Developments in Membrane Technologies and Ion-Exchange Methods for Arsenic Removal from Aquatic Ecosystems 315 Muhammad Bilal Shakoor, Israr Masood ul Hasan, Sajid Rashid Ahmad, Mujahid Farid, Muzaffar Majid, Irshad Bibi, Asim Jilani, Tanzeela Kokab, and Nabeel Khan Niazi 16.1 Introduction 315 16.2 Arsenic Chemistry, Sources, and Distribution in Water 316 16.3 Health Implications of Arsenic 318 16.4 Membrane Technologies 319 16.4.1 High-Pressure Membranes 319 16.4.1.1 Reverse Osmosis 319 16.4.1.2 Nanofiltration 320 16.4.2 Low-Pressure Membrane 320 16.4.2.1 Microfiltration 320 16.4.2.2 Ultrafiltration 321 16.5 Ion Exchange 322 16.5.1 Ion-Exchange Resins 323 16.5.2 Polymeric Ligand Exchangers 323 16.5.3 Fe-Loaded Resins 324 16.5.4 Cu(II)-Loaded Resins 325 16.6 Conclusion 325 Acknowledgments 326 References 326 17 Arsenic Removal by Membrane Technologies and Ion Exchange Methods from Wastewater 330 Simranjeet Singh, Harry Kaur, Daljeet Singh Dhanjal, Praveen C. Ramamurthy, and Joginder Singh 17.1 Introduction 330 17.2 Arsenic Removal Using Membrane Separation 331 17.2.1 Microfiltration 332 17.2.2 Nanofiltration 333 17.2.3 Reverse Osmosis 333 17.2.4 Ultrafiltration 334 17.3 Arsenic Removal Using Ion Exchange Methods 334 17.3.1 Ion Exchange Resin 334 17.3.2 Ion Exchange Fiber 335 17.4 Methods to Increase the Efficiency of Arsenic Removal 336 17.4.1 Oxidation 336 17.4.2 Adsorption 337 17.4.3 Coagulation and Flocculation 337 17.4.4 Phytoremediation 338 17.5 Conclusion 338 Acknowledgments 339 References 339 18 Methods to Detect Arsenic Compounds 345 Shraddha Mishra and Sanjay Kumar Verma 18.1 Introduction 345 18.2 Colorimetric Method 347 18.3 Electrochemical Method 347 18.4 Method Based on FRET 348 18.5 Method Based on SPR 349 18.6 Method Based on Spectrometry 349 18.6.1 Atomic Absorption Spectrometry 350 18.6.1.1 Hydride Generation Atomic Absorption Spectrometry 351 18.6.1.2 Electrothermal/Graphite Furnace Atomic Absorption Spectrometry 351 18.6.2 Atomic Fluorescence Spectrometry 352 18.6.3 Inductively Coupled Plasma Techniques 352 18.6.3.1 Inductively Coupled Plasma Mass Spectrometry 353 18.6.3.2 Inductively Coupled Plasma/Optical Emission Spectrometry 353 18.7 Biosensor for Arsenic Detection 353 18.7.1 Whole Cell-Based Biosensor 354 18.7.1.1 Green Fluorescent Protein-Based Biosensor 355 18.7.1.2 Bioluminescence/Luciferase-Based Biosensor 356 18.7.1.3 β-galactosidase/lacZ-based biosensor 356 18.7.1.4 Whole-Cell Biosensor Based on Other Approaches 357 18.7.2 Cell-Free/Biomolecules-Based Biosensor 358 18.7.2.1 DNA-Based Biosensor 358 18.7.2.2 Aptamer-Based Biosensors 359 18.7.2.3 Protein-Based Biosensors 361 18.8 Conclusion 362 References 362 19 An Overview on Emerging and Innovative Technologies for Regulating Arsenic Toxicity in Plants 367 Arun Kumar, Pradeep Kumar Yadav, and Anita Singh 19.1 Introduction 367 19.2 Uptake of Arsenic 368 19.3 Arsenic Toxicity on Plants 370 19.4 Remediation Strategies of Arsenic Toxicity in Plants 373 19.4.1 With the Application of Signaling Molecules and Phytohormones 373 19.4.2 With the Application of Nano Particles 377 19.4.3 With the Application of Genetic Manipulations 379 19.5 Conclusion 381 Acknowledgments 381 References 384 20 A Potential Phytoremedial Strategy for Arsenic from Contaminated Drinking Water Using Hygrophilla spinosa (Starthorn Leaves) 395 Nilanjana Roy Chowdhury, Debapriya Sinha, Antara Das, Madhurima Joardar, Anuja Joseph, Iravati Ray, Deepanjan Mridha, Ayan De, and Tarit Roychowdhury 20.1 Introduction 395 20.2 Methodology 397 20.2.1 Adsorbent 397 20.2.2 Sample Collection and Preparation of Adsorbent 397 20.2.2.1 Sampling Site 397 20.2.2.2 Preparation of Material 397 20.2.3 Adsorbate 399 20.2.4 The Batch Adsorption Study 399 20.2.5 Estimation of As 399 20.2.6 Estimation of Fe 399 20.2.7 Calculation 400 20.2.8 Quality Control and Quality Assurance 400 20.2.9 Statistical Evaluation 400 20.3 Results and Discussion 400 20.3.1 Effect of Adsorbent Dosage 400 20.3.2 Effect of Contact Time 402 20.3.3 Effect of pH 403 20.3.4 Effect of RPM 405 20.4 Conclusion 407 References 408 Index 411

Comprehensive resource detailing the chemistry, toxicity and impact of arsenic in plants, and solutions to the problem Arsenic in Plants: Uptake, Consequences and Remediation Techniques provides comprehensive coverage of the subject, detailing arsenic in our environment, the usage of arsenicals in crop fields, phytotoxicity of arsenic and arsenic’s impact on the morphology, anatomy and quantitative and qualitative traits of different plant groups, including their physiology and biochemistry. The work emphasizes the occurrence of arsenic, its speciation and transportation in plants, and differences in mechanisms of tolerance in hyper-accumulator and non-accumulator plants. Throughout the text, the highly qualified authors delve into every facet of the interaction of arsenic with plants, including the ionomics, genomics, transcriptomics and proteomics in relation to arsenic toxicity, impact of exogenous phytohormones and growth-regulating substances, management of arsenic contamination in the soil-plant continuum, phytoremediation of arsenic toxicity and physical removal of arsenic from water. General discussion has also been included on subjects such as the ways through which this metalloid affects plant and human systems. Topics covered include: Introduction and historical background of arsenic and the mechanism of arsenic transport and metabolism in plantsArsenic-induced responses in plants, including impact on biochemical processes and different plant groups, from cyanobacteria to higher plantsThe role of phytohormones, mineral nutrients, metabolites and signaling molecules in regulating arsenic-induced toxicity in plantsGenomic, proteomic, metabolomic, ionomic and transcriptional regulation during arsenic stressStrategies to reduce the arsenic contamination in soil-plant systems and arsenic removal by phytoremediation techniques Researchers, academics, and students of plant physiology, biotechnology, and agriculture will find valuable information in Arsenic in Plants to understand this pressing subject in full, along with its implications and how we can adapt our strategies and behaviors to promote reduced contamination through practical applications.