Principles of Environmental Chemistry Principles of Environmental Chemistry Roy M Harrison School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK ISBN-13:978-0-85404-371-2 AcataloguerecordforthisbookisavailablefromtheBritishLibrary rTheRoyalSocietyofChemistry2007 Allrightsreserved Apart from fair dealing for the purposes of research for non-commercial purposes or for privatestudy,criticismorreview,aspermittedundertheCopyright,DesignsandPatents Act1988andtheCopyrightandRelatedRightsRegulations2003,thispublicationmaynot be reproduced, stored or transmitted, in any form or by any means, without the prior permissioninwritingofTheRoyalSocietyofChemistry,orinthecaseofreproductionin accordancewiththetermsoflicencesissuedbytheCopyrightLicensingAgencyintheUK, or in accordance with the terms of the licences issued by the appropriate Reproduction RightsOrganizationoutsidetheUK.Enquiriesconcerningreproductionoutsidetheterms statedhereshouldbesenttoTheRoyalSocietyofChemistryattheaddressprintedonthis page. PublishedbyTheRoyalSocietyofChemistry, ThomasGrahamHouse,SciencePark,MiltonRoad, CambridgeCB40WF,UK RegisteredCharityNumber207890 Forfurtherinformationseeourwebsiteatwww.rsc.org TypesetbyMacmillanIndiaLtd,Bangalore,India PrintedbyHenryLingLtd,Dorchester,Dorset,UK Preface While this book is in its first edition, it nonetheless has a lengthy pedigree, which derives from a book entitled Understanding Our Envi- ronment: An Introduction to Environmental Chemistry and Pollution, which ran to three editions, the last of which was published in 1999. Understanding Our Environment has proved very popular as a student textbook, but changes in the way that the subject is taught had neces- sitated its splitting into two separate books. When Understanding Our Environment was first published, neither environmentalchemistry norpollution wastaught in manyuniversities, andmostofthosecourseswhichexistedwererelativelyrudimentary.In many cases, no clear distinction was drawn between environmental chemistry and pollution and the two were taught largely hand in hand. Nowadays, the subjects are taught in far more institutions and in a far more sophisticated way. There is consequently a need to reflect these changes in what would have been the fourth edition of Understanding Our Environment, and after discussion with contributors to the third editionandwiththeRoyalSocietyofChemistry,itwasdecidedtodivide the former book into two and create new books under the titles respec- tively of An Introduction to Pollution Science and Principles of Environ- mental Chemistry. Because of the authoritative status of the authors of Understanding Our Environment and highly positive feedback which we had received on the book, it was decided to retain the existing chapters where possible while updating the new structure to enhance them through the inclusion of further chapters. This division of the earlier book into two new titles is designed to accommodate the needs of what are now two rather separate markets. An Introduction to Pollution Science is designed for courses within degrees in environmental sciences, environmental studies and related areasincludingtaughtpostgraduatecourses,whicharenotembeddedin a specific physical science or life science discipline such as chemistry, v vi Preface physics or biology. The level of basic scientific knowledge assumed of thereaderisthereforeonlythatofthegeneralistandthebookshouldbe accessible to a very wide readership including those outside of the academic world wishing to acquire a broadly based knowledge of pollution phenomena. The second title, Principles of Environmental Chemistry assumes a significant knowledge of chemistry and is aimed far more at courses on environmental chemistry which are embedded withinchemistrydegreecourses.Thebookwill thereforebesuitablefor students taking second or third year option courses in environmental chemistry or those taking specialised Masters’ courses, having studied the chemical sciences at first-degree level. InthisvolumeIhavebeenfortunatetoretaintheservicesofanumber of authors from Understanding Our Environment. The approach has been to update chapters from that book where possible, although some of the new authors have decided to take a completely different ap- proach. The book initially deals with the atmosphere, freshwaters, the oceans and the solid earth as separate compartments. There are certain commoncrosscuttingfeaturessuchasnon-idealsolutionchemistry,and where possible these are dealt with in detail where they first occur, with suitablecross-referencingwhentheyre-appearatlaterpoints.Chemicals in the environment do not respect compartmental boundaries, and indeed many important phenomena occur as a result of transfers between compartments. The book therefore contains subsequent chap- tersonenvironmentalorganicchemistry,whichemphasisesthecomplex behaviour of persistent organic pollutants, and on biogeochemical cy- clingofpollutants,includingmajorprocessesaffectingbothorganicand inorganic chemical species. Iamgratefultotheauthorsformakingavailabletheirgreatdepthand breadth of experience to the production of this book and for tolerating my many editorial quibbles. I believe that their contributions have createdabookofwidespreadappeal,whichwillfindmanyeagerreaders both on taught courses and in professional practice. Roy M. Harrison Birmingham, UK Contents Chapter 1 Introduction 1 R.M. Harrison 1.1 The Environmental Sciences 1 1.2 Environmental Chemical Processes 3 1.3 Environmental Chemicals 3 1.4 Units of Concentration 5 1.4.1 Atmospheric Chemistry 5 1.4.2 Soils and Waters 6 1.5 The Environment as a Whole 7 References 7 Chapter 2 Chemistry of the Atmosphere 8 P.S. Monks 2.1 Introduction 8 2.2 Sources of Trace Gases in the Atmosphere 10 2.3 Initiation of Photochemistry by Light 11 2.4 Tropospheric Chemistry 17 2.5 Tropospheric Oxidation Chemistry 20 2.5.1 NitrogenOxidesandthePhotostationaryState 26 2.5.2 Production and Destruction of Ozone 28 2.5.3 Role of Hydrocarbons 35 2.5.4 Urban Chemistry 37 2.6 Night-Time Oxidation Chemistry 40 2.7 Ozone-Alkene Chemistry 46 2.8 Sulfur Chemistry 46 2.9 Halogen Chemistry 51 2.9.1 Tropospheric Halogens and Catalytic Destruction of Ozone 56 vii viii Contents 2.10 Stratospheric Chemistry 58 2.10.1 The Antarctic Ozone Hole 63 2.11 Summary 72 Questions 72 References 76 Chapter 3 Chemistry of Freshwaters 80 M.C. Graham and J.G. Farmer 3.1 Introduction 80 3.2 Fundamentals of Aquatic Chemistry 82 3.2.1 Introduction 82 3.2.2 Dissolution/Precipitation Reactions 91 3.2.3 Complexation Reactions in Freshwaters 94 3.2.4 Species Distribution in Freshwaters 97 3.2.5 Modelling Aquatic Systems 121 3.3 Case Studies 122 3.3.1 Acidification 122 3.3.2 Metals and Metalloids in Water 130 3.3.3 HistoricalPollutionRecordsandPerturbatory Processes in Lakes 139 3.3.4 Nutrients in Water and Sediments 145 3.3.5 Organic Matter and Organic Chemicals in Water 150 Questions and Problems 157 Further Reading 159 References 159 Chapter 4 Chemistry of the Oceans 170 S.J. de Mora 4.1 Introduction 170 4.1.1 The Ocean as a Biogeochemical Environment 170 4.1.2 Properties of Water and Seawater 173 4.1.3 Salinity Concepts 177 4.1.4 Oceanic Circulation 179 4.2 Seawater Composition and Chemistry 182 4.2.1 Major Constituents 182 4.2.2 Dissolved Gases 184 4.2.3 Nutrients 199 4.2.4 Trace Elements 201 4.2.5 Physico-Chemical Speciation 204 4.3 Suspended Particles and Marine Sediments 210 Contents ix 4.3.1 Description of Sediments and Sedimentary Components 210 4.3.2 Surface Chemistry of Particles 213 4.3.3 Diagenesis 218 4.4 Physical and Chemical Processes in Estuaries 219 4.5 Marine Contamination and Pollution 223 4.5.1 Oil Slicks 223 4.5.2 Plastic Debris 226 4.5.3 Tributyltin 228 Questions 230 References 231 Chapter 5 The Chemistry of the Solid Earth 234 I.D. Pulford 5.1 Introduction 234 5.2 Mineral Components of Soil 238 5.2.1 Inputs 238 5.2.2 Primary Minerals 238 5.2.3 Secondary Minerals 240 5.2.4 Weathering Processes (See also Chapter 3) 246 5.3 Organic Components of Soil 248 5.4 Soil pH And Redox Potential 254 5.4.1 pH and Buffering 254 5.4.2 Soil Acidity 255 5.4.3 Soil Alkalinity 257 5.4.4 Influence of pH on Soils 258 5.4.5 Redox Potential 260 5.4.6 Reduction Processes in Soil 261 5.5 Chemical Reactions in Soil 263 5.5.1 Reactions in Soil Solution 263 5.5.2 Ion Exchange (Physisorption) 267 5.5.3 Ligand Exchange (Chemisorption) 271 5.5.4 Complexation/Chelation 273 5.5.5 Precipitation/Dissolution 273 5.5.6 Soil Processes 275 Questions 275 References 278 Chapter 6 Environmental Organic Chemistry 279 C.J. Halsall 6.1 Introduction 279