Environmental Organic Chemistry

Citation

Schwarzenbach, R. P., Gschwend, P. M., & Imboden, D. M. (2016). Environmental Organic Chemistry (3rd ed.). Wiley.

Chapter Summary

The third edition has an introductory chapter followed by 27 chapters grouped into six parts, with an appendix, in about 1,000 pages. The authors state a deliberately broad aim: to integrate the whole field, from molecular interactions to the dynamics of whole environmental systems, as a textbook for students of environmental science and engineering, earth sciences, chemistry and physics and as a reference for practitioners. The text is written in a somewhat colloquial style, each chapter ends with questions, problems and a bibliography, and the reading is meant to build toward the quantitative assessment of exposure to organic chemicals.

Chapter 1: General Topic and Overview

Introduces the assessment of organic chemicals in the environment and gives a guided tour of the book's six parts.

Part I, Chapters 2–6: Background Knowledge

Five chapters of varied content that supply the chemistry, physics and mathematics needed later. Chapter 2, Background Knowledge on Organic Chemicals, reviews the makeup of organic compounds and intermolecular forces. Chapter 3, The Amazing World of Anthropogenic Organic Chemicals, surveys groups of chemicals such as persistent organic pollutants, petroleum hydrocarbons, solvents, flame retardants, polyfluorinated chemicals, pharmaceuticals and pesticides, and introduces the "companion compounds" used as model chemicals throughout. Chapter 4, Background Thermodynamics, Equilibrium Partitioning and Acidity Constants, covers thermodynamic functions and organic acids and bases. Chapter 5, Earth Systems and Compartments, describes the atmosphere, surface waters and sediments, soil and groundwater, and biota. Chapter 6, Environmental Systems: Physical Processes and Mathematical Modeling, introduces box models and transport in space and time.

Part II, Chapters 7–11: Equilibrium Partitioning in Well-Defined Systems

Chapter 7 treats partitioning between bulk phases and linear free energy relationships. Chapter 8 is on vapor pressure; Chapter 9 on aqueous solubility, activity coefficients and the air–water partition constant; Chapter 10 on organic liquid–air and organic liquid–water partitioning, including the octanol–water system; and Chapter 11 on partitioning of nonionic compounds between well-defined surfaces and air or water.

Part III, Chapters 12–16: Equilibrium Partitioning in Environmental Systems

Chapter 12 introduces sorption isotherms and the solid–water distribution coefficient. Chapter 13 covers sorption to natural organic matter, Chapter 14 sorption of ionic compounds to charged surfaces, Chapter 15 aerosol–air partitioning with dry and wet deposition, and Chapter 16 partitioning to biota, including bioaccumulation, biomagnification and baseline toxicity (narcosis).

Part IV, Chapters 17–20: Mass Transfer Processes in Environmental Systems

Chapter 17 covers random motion and molecular and turbulent diffusivity; Chapter 18 transport at boundaries; Chapter 19 air–water exchange; and Chapter 20 interfaces involving solids, namely the sediment–water interface and transport in unsaturated soil.

Part V, Chapters 21–27: Transformation Processes

Chapter 21 gives background on reactive sites, thermodynamics and kinetics of transformations. The next chapters treat hydrolysis and reactions with other nucleophiles (22), redox reactions (23), direct photolysis in aquatic systems (24), indirect photolysis with photooxidants in natural waters and the atmosphere (25), biotransformations (26) and the assessment of transformations using compound-specific isotope analysis (27).

Part VI, Chapter 28: Exposure Assessment of Organic Pollutants Using Simple Modeling Approaches

The final chapter puts the pieces together with the one-box model, equilibrium partitioning in simple multimedia systems, simple dynamic systems and systems driven by advection. An appendix follows.

Key Concepts

Parts I–II

• Partition constants: ratios that describe how a compound distributes between air, water, organic liquids and surfaces.
• Linear free energy relationships: correlations used to estimate partition constants from molecular structure.
• Box models: the simplest quantitative models of environmental systems.

Parts III–IV

• Sorption and the distribution coefficient: binding to natural organic matter, mineral surfaces and aerosols.
• Bioaccumulation and biomagnification: partitioning to organisms and up the food chain.
• Air–water exchange and boundary transport: kinetic limits on mass transfer.

Parts V–VI

• Transformation pathways: hydrolysis, redox reactions, photolysis and biotransformation.
• Compound-specific isotope analysis: a tool for assessing transformation in laboratory and field.
• Exposure assessment: combining partitioning, transport and reaction in models.

Critical Analysis

Strengths

• A single logic from structure to environmental fate. The structure runs from molecular interactions and equilibrium partitioning to kinetics and transformation and then to modeling, and the authors show that the properties in Part II feed the discussions of sorption and mass transfer in later parts.
• Pedagogical apparatus. Each chapter ends with questions that point to its most important aspects and with problems; the publisher notes a companion website with solutions to all problems and a large compilation of physical constants and compound properties.
• Well-defined entry points. The authors suggest that Part I can be read before the course or consulted section by section, and that chapters within later parts can often be read independently.
• Teaching treatment of partitioning and transformation. The publisher describes this edition as a more holistic and teachable treatment of phase partitioning and transformation processes.

Limitations

• Breadth over depth. The authors say the book introduces and integrates the most important aspects of all relevant topics and is not an exhaustive treatment of any one, so specialists will turn to the literature citations supplied.
• Length and demands. At about 1,000 pages, the book draws on thermodynamics, kinetics and mathematical modeling throughout, and the authors advise readers with little organic chemistry background to consult an introductory organic text.
• Synthesis depends on everything before it. The authors note that solving the case studies of Chapter 28 commonly means going back to information from many earlier chapters, so that chapter cannot be used on its own.

Where It Fits in the Course

Within the environmental and green chemistry course, this is a graduate-level treatment of organic chemicals in water, soil, air and organisms. Chemistry in Context introduces chemistry through environmental and societal issues; Raff and Hites's Elements of Environmental Chemistry is a short, quantitative introduction to estimating concentrations and fluxes; and Manahan's Environmental Chemistry applies chemical principles across the atmosphere, water, soil and living systems. Any of them is suitable preparation. Lancaster's Green Chemistry concerns the design of safer chemical products and processes, which is complementary to assessing the fate of existing chemicals.

Seinfeld and Pandis's Atmospheric Chemistry and Physics is the natural companion: it concentrates on the atmosphere, its gases and particles, whereas Schwarzenbach, Gschwend and Imboden follow organic chemicals through all environmental compartments. Their chapters on aerosol–air partitioning, air–water exchange and photooxidation in the atmosphere overlap with that book.

How to Use This Book

The book suits graduate students and advanced undergraduates in environmental science, engineering and chemistry, and practitioners who need to estimate the behavior of organic pollutants. Organic and physical chemistry are the working prerequisites; Part I supplies the chemistry, physics, mathematics and environmental background that the later parts use.

A practical plan:

• Foundation: Part I, reading Chapters 4 and 6 closely and treating Chapters 2, 3 and 5 as review or reference.
• A reasonable core for a course on environmental fate: Part II, then Chapters 12, 13 and 16 from Part III, then Chapters 19, 21, 22 and 23.
• Optional by interest: Chapters 14 and 15 for ionic compounds and aerosols, Chapters 24 and 25 for photochemistry, Chapter 26 for biotransformation and Chapter 27 for isotope analysis.
• Synthesis: Chapter 28, once the building blocks are in place.

Answer the end-of-chapter questions, then use the problems and the companion website to check calculations.