Reactive Transport in Porous Media, edited by P. C. Lichtner, C. I. Steefel and E. H. Oelkers. Reviews in Mineralogy, Vol. 34. Mineralogical Society of America, Washington, DC, 1996. 438 pp. ISBN 0 939 95042 1. Price $28.00.

This volume continues the generally high standard of the Mineralogical Society of America series with a set of contributions on fluid transport in reactive media. This field of endeavour is an extremely multi-disciplinary one, of interest to and with significant contributions from geologists, geochemists, physicists, engineers and biologists. Given this wide range, the editors have done an excellent job in compiling a set of contributions which generally fit well together, and between them they cover models of transport and reaction, properties and heterogeneities of geological porous media, natural ion exchange and microbiological processes, and a case study of modelling of contaminated ground-water. There is a general focus on application of reactive transport models to prediction of contaminant migration in the subsurface. This is a key topic in the Earth sciences at the present time, as such models can potentially be used to rationalize data from monitoring of contaminated plumes, allowing a maximum of information to be derived from relatively sparse monitoring data. In another context, such models are our only way of predicting the behaviour of contaminants around likely nuclear waste disposal sites on long time-scales. It is thus vital that the applicability and validity of such models be tested so that realistic limits can be placed on the confidence which one can have in any hydrogeological models of contaminant dispersion based on them. It is refreshing to see that most of the contributions contain at least some assessment of the limitations imposed by the models themselves but there is clearly much to be done to refine and validate this approach.

The first three chapters (Lichtner; Steefel & MacQuarrie; Oelkers) feature extensive description and review of reactive mass transport models and of the physical and chemical properties of rocks and fluids under consideration. This latter topic is further discussed in a chapter on reactive transport in heterogeneous systems by Thompson & Jackson, which provides a much-needed warning about the limitations imposed on modelling by the very nature of geological materials. By stressing the way that geological inhomogeneity affects contaminant migration the authors provide a particularly timely reminder of the need for adequate characterization of both flow properties and chemistry of geological media in modelling of pollutant dilution, retardation and reaction.

Ion exchange and chromatographic effects in natural systems are given a thorough coverage in a chapter by Appelo. After an introduction to exchange and chromatographic theory, their application between groundwater and aquifer matrix materials is discussed. In particular, those cases where hydrochemical signals from chromatographic processes are likely to be preserved are distinguished f