- Email: [email protected]
Environmental Applications of Geochemical Modeling
Chemical Geology 198 (2003) 139 – 140 www.elsevier.com/locate/chemgeo
Book review
Environmental Applications of Geochemical Modeling Chen Zhu and Greg Anderson—Cambridge University Press My copy of ‘Environmental Applications of Geochemical Modeling’ by Chen Zhu and Greg Anderson arrived just before Stacey, Emily (our two-year-old), and I were off to Austin to visit family for the Christmas holiday. So, I tossed it into the bag along with several of Emily’s books to read during the trip. While in Austin, between eating massive quantities of steaks and watching football on television, I spent my time reading and rereading two books: ‘Environmental Applications of Geochemical Modeling’ and ‘Harry the Dirty Dog’ by Gene Zion and Margaret Bloy Grahm. While reading these books, I noted several interesting similarities and contrasts. Both books explore the fate and consequences of environmental pollution. In ‘Harry the Dirty Dog’, first published in 1956, Harry plays in the train yard and gets dirty; he plays in a coal mine and gets even dirtier. He gets so dirty he is changed from a white dog with black spots to a black dog with white spots. A solution is found to resolve some of these consequences of environmental pollution; Harry is given a bath. I suspect this summed up the state of the art on how to solve environmental problems in 1956. Chen and Anderson’s new book ‘Environmental Applications of Geochemical Modeling’ provides insights into many of the advances that have arrived since ‘Harry the Dirty Dog’ was first published. Considering the vast number of advances, there is no doubt that a new guidebook to geochemical modeling is needed. Part of this need is described by Chen and Anderson in their Introduction. They present the results of a search performed on the US Environmental Protection Agency’s Records of Decidoi:10.1016/S0009-2541(02)00382-0
sion CD-ROM. Of the total number of records mentioning models of various kinds, 533 mention only groundwater flow models, 93 mention transport models, but only 41 mention geochemical models. A similar survey of the September 2000 Superfund Public Information CD-ROM found only 6 of 1206 records mentioning geochemical modeling. I suspect that many geochemists find this result a bit shocking. For some reason, perhaps due to the lack of adequately trained scientists, geochemical modeling has lagged dramatically transport and flow modeling in environmental studies. With luck, the appearance of this book, which in my opinion is long overdue, will begin to correct this deficiency. This book follows a direct and logical path starting with some simple modeling basics and thermodynamic background, passing through aqueous speciation, mineral solubility and surface adsorption modeling, and winding up with more complex reaction path and coupled reactive path modeling. The book is written in a style that makes it approachable to the enlightened nonexpert, and even contains a scattering of personal advice from the authors, as if they were in fact lecturing to the reader. For example, on p. 106, one finds the advice, ‘Modeling work is not complete until it is effectively presented either orally or in a report. Often managers or regulators, who review the geochemical modeling work are not experts on the subject. Clear presentation is the key’. Much of ‘Environmental Applications of Geochemical Modeling’ reports on how Chen Zhu has used various computational tools to provide insight into geochemical problems. As such, it provides an answer to that question often asked in my office by first year graduate students: ‘What the f**k is that modeling s**t all about, anyway?’ The emphasis in this book is on how to apply several readily available computer codes to model the geochemical evolution of experimental and natural systems. The main com-
140
Book review
puter codes used and explained in this book are PHREEQC and MINTEQA2, both of which are available free of charge from the addresses and/or websites listed in the book. Some other computer codes: EQ3/6, NETPATH, SUPCRT92, EQBRM, SOLMINEQ.88, SOLVEQ, CHILLER, MINEQL+, and The Geochemists Workbench are introduced, but not extensively described or used. This book provides a survey of these tools and what they can do, rather than a users guide to the codes. Users guides are generally available for each of these codes, though quite honestly, many of them are challenging to follow. A point that struck me about this book is that it is aimed at how to apply geochemical modeling codes, but NOT at how they actually work. Throughout the book, one finds statements like: Geochemical models have been extensively reviewed in the literature. Here, we describe them only briefly. More detailed descriptions of models can be found in the above-mentioned reviews, the manuals for the geochemical modeling codes . . . (p. 24). The mathematical formulation of equilibrium speciation– solubility models and the numerical methods to solve algebraic equations are described elsewhere, and we shall not repeat them here (p. 76). We will say very little about the numerical methods these programs use (p. 79). The mathematical foundations are not difficult, but we omit these aspects here, and try instead to convey a sense of what modeling achieves and does not achieve (p. 159). We omit the mathematical development here. Serious modelers should read . . . (p. 183). The reader is frequently directed to other sources to discover the details of how these modeling calculations actually work. The degree to which this is a benefit or a drawback to this book depends on the reader. I suspect that for many, this is a benefit. Many users of computer modeling codes just want to know how to run the codes and get on with their lives. This is likely a big advantage for the casual user and for teaching computer applications in aqueous geochemistry, as large sets of complex equations tend to strike
fear among Earth Scientists. For the few of us that like knowing what is inside the black box, however, this superficial treatment of the fundamentals of geochemical modeling may prove frustrating. A strong point of this book is that it is filled with worked examples including PHREEQC, EQ3/6 and REACT input files/scripts. I always find it useful, when using new computer codes, to have several worked examples available to me to aid in learning how the code work. Most of these worked examples come directly from Chen Zhu’s research. Some examples, notably the geochemical evolution of fluids and geochemical transport at the Bear Creek Uranium Mill Tailings Impoundment, are used throughout the book to illustrate the various aspects of Geochemical Modeling, ranging from simple speciation calculations to reaction transport models. One should be warned, however, that this book will be most useful over the next few years. Computer codes tend to evolve quickly, with new geochemical modeling codes or revised versions of existing codes arriving each year. As such, I fear that 15 years from now, ‘Environmental Applications of Geochemical Modeling’ will begin to look as naive as ‘Harry the Dirty Dog’ looks today. One major difference between these two books is their relative price. The copy of ‘Harry the Dirty Dog’ that I read claimed its original price was US$15.00, which I consider very steep for 32 pages of illustrated text. Amazon sells it for US$11.17. Either way you look at it, its over US$0.30 a page. I suppose if it were a required undergraduate text, most students would just Xerox it cover to cover. In contrast, ‘Environmental Applications of Geochemical Modeling’ is a downright bargain. According to the Cambridge University Press webpage, the 289-page soft cover edition costs only US$40, which I suspect will be lower than many of our bar tabs at the upcoming Goldschmidt meeting in Davos. Considering its value and timeliness, I have little doubt this book will find its way onto most of our bookshelves very soon. Eric H. Oelkers Laboratoire de Ge´ochimie, Universite´ Paul Sabatier, CNRS UMR 5563, 38 rue des Trente-Six Ponts, 31400 Toulouse, France E-mail address: [email protected]
Book review
Environmental Applications of Geochemical Modeling Chen Zhu and Greg Anderson—Cambridge University Press My copy of ‘Environmental Applications of Geochemical Modeling’ by Chen Zhu and Greg Anderson arrived just before Stacey, Emily (our two-year-old), and I were off to Austin to visit family for the Christmas holiday. So, I tossed it into the bag along with several of Emily’s books to read during the trip. While in Austin, between eating massive quantities of steaks and watching football on television, I spent my time reading and rereading two books: ‘Environmental Applications of Geochemical Modeling’ and ‘Harry the Dirty Dog’ by Gene Zion and Margaret Bloy Grahm. While reading these books, I noted several interesting similarities and contrasts. Both books explore the fate and consequences of environmental pollution. In ‘Harry the Dirty Dog’, first published in 1956, Harry plays in the train yard and gets dirty; he plays in a coal mine and gets even dirtier. He gets so dirty he is changed from a white dog with black spots to a black dog with white spots. A solution is found to resolve some of these consequences of environmental pollution; Harry is given a bath. I suspect this summed up the state of the art on how to solve environmental problems in 1956. Chen and Anderson’s new book ‘Environmental Applications of Geochemical Modeling’ provides insights into many of the advances that have arrived since ‘Harry the Dirty Dog’ was first published. Considering the vast number of advances, there is no doubt that a new guidebook to geochemical modeling is needed. Part of this need is described by Chen and Anderson in their Introduction. They present the results of a search performed on the US Environmental Protection Agency’s Records of Decidoi:10.1016/S0009-2541(02)00382-0
sion CD-ROM. Of the total number of records mentioning models of various kinds, 533 mention only groundwater flow models, 93 mention transport models, but only 41 mention geochemical models. A similar survey of the September 2000 Superfund Public Information CD-ROM found only 6 of 1206 records mentioning geochemical modeling. I suspect that many geochemists find this result a bit shocking. For some reason, perhaps due to the lack of adequately trained scientists, geochemical modeling has lagged dramatically transport and flow modeling in environmental studies. With luck, the appearance of this book, which in my opinion is long overdue, will begin to correct this deficiency. This book follows a direct and logical path starting with some simple modeling basics and thermodynamic background, passing through aqueous speciation, mineral solubility and surface adsorption modeling, and winding up with more complex reaction path and coupled reactive path modeling. The book is written in a style that makes it approachable to the enlightened nonexpert, and even contains a scattering of personal advice from the authors, as if they were in fact lecturing to the reader. For example, on p. 106, one finds the advice, ‘Modeling work is not complete until it is effectively presented either orally or in a report. Often managers or regulators, who review the geochemical modeling work are not experts on the subject. Clear presentation is the key’. Much of ‘Environmental Applications of Geochemical Modeling’ reports on how Chen Zhu has used various computational tools to provide insight into geochemical problems. As such, it provides an answer to that question often asked in my office by first year graduate students: ‘What the f**k is that modeling s**t all about, anyway?’ The emphasis in this book is on how to apply several readily available computer codes to model the geochemical evolution of experimental and natural systems. The main com-
140
Book review
puter codes used and explained in this book are PHREEQC and MINTEQA2, both of which are available free of charge from the addresses and/or websites listed in the book. Some other computer codes: EQ3/6, NETPATH, SUPCRT92, EQBRM, SOLMINEQ.88, SOLVEQ, CHILLER, MINEQL+, and The Geochemists Workbench are introduced, but not extensively described or used. This book provides a survey of these tools and what they can do, rather than a users guide to the codes. Users guides are generally available for each of these codes, though quite honestly, many of them are challenging to follow. A point that struck me about this book is that it is aimed at how to apply geochemical modeling codes, but NOT at how they actually work. Throughout the book, one finds statements like: Geochemical models have been extensively reviewed in the literature. Here, we describe them only briefly. More detailed descriptions of models can be found in the above-mentioned reviews, the manuals for the geochemical modeling codes . . . (p. 24). The mathematical formulation of equilibrium speciation– solubility models and the numerical methods to solve algebraic equations are described elsewhere, and we shall not repeat them here (p. 76). We will say very little about the numerical methods these programs use (p. 79). The mathematical foundations are not difficult, but we omit these aspects here, and try instead to convey a sense of what modeling achieves and does not achieve (p. 159). We omit the mathematical development here. Serious modelers should read . . . (p. 183). The reader is frequently directed to other sources to discover the details of how these modeling calculations actually work. The degree to which this is a benefit or a drawback to this book depends on the reader. I suspect that for many, this is a benefit. Many users of computer modeling codes just want to know how to run the codes and get on with their lives. This is likely a big advantage for the casual user and for teaching computer applications in aqueous geochemistry, as large sets of complex equations tend to strike
fear among Earth Scientists. For the few of us that like knowing what is inside the black box, however, this superficial treatment of the fundamentals of geochemical modeling may prove frustrating. A strong point of this book is that it is filled with worked examples including PHREEQC, EQ3/6 and REACT input files/scripts. I always find it useful, when using new computer codes, to have several worked examples available to me to aid in learning how the code work. Most of these worked examples come directly from Chen Zhu’s research. Some examples, notably the geochemical evolution of fluids and geochemical transport at the Bear Creek Uranium Mill Tailings Impoundment, are used throughout the book to illustrate the various aspects of Geochemical Modeling, ranging from simple speciation calculations to reaction transport models. One should be warned, however, that this book will be most useful over the next few years. Computer codes tend to evolve quickly, with new geochemical modeling codes or revised versions of existing codes arriving each year. As such, I fear that 15 years from now, ‘Environmental Applications of Geochemical Modeling’ will begin to look as naive as ‘Harry the Dirty Dog’ looks today. One major difference between these two books is their relative price. The copy of ‘Harry the Dirty Dog’ that I read claimed its original price was US$15.00, which I consider very steep for 32 pages of illustrated text. Amazon sells it for US$11.17. Either way you look at it, its over US$0.30 a page. I suppose if it were a required undergraduate text, most students would just Xerox it cover to cover. In contrast, ‘Environmental Applications of Geochemical Modeling’ is a downright bargain. According to the Cambridge University Press webpage, the 289-page soft cover edition costs only US$40, which I suspect will be lower than many of our bar tabs at the upcoming Goldschmidt meeting in Davos. Considering its value and timeliness, I have little doubt this book will find its way onto most of our bookshelves very soon. Eric H. Oelkers Laboratoire de Ge´ochimie, Universite´ Paul Sabatier, CNRS UMR 5563, 38 rue des Trente-Six Ponts, 31400 Toulouse, France E-mail address: [email protected]