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meets the significance criterion, that subject is not ment ioned or is referred to only in passing. This results in gaps in coverage. For example, the chapter on institutional arrangements includes a section on fisheries management, but there is no ment ion of fisheries in the chapter on resource appraisal or that on resource allocation. Similarly, "waste" and "waste disposal" are each cited to four pages in the index, every instance merely being a reference in passing. This would seem to slight the huge dimension of this problem in the United States, as well as in other countries.

Another shortcoming of the author's technique flows from the fact that the investigations described and summarized tend to be in one degree or another localized-on a single community , river basin, etc., or at most on national pol- icy with respect to such issues as land use and wilderness management. Yet the chapter on hazards and risk assessment opens with reference to one au- thor's view of geography as "the science of human ecology" (that "identi ty" preoccupation again! ). If this view has any validity, the book can be faulted for failing to mention, in the chapter on carrying capacity, the problem of human population growth and its effects on the planet as a whole.

Such criticisms notwithstanding, the book is well crafted for its intended purpose: the teaching of new researchers in geography.

Bruce C. Netschert Special Consultant

National Economic Research Associates, Inc.

Washington, DC, USA

Health guidelines for the use of wastewater in agriculture and aquaculture. Re- port of a WHO Scientific Group, Technical Report Series No. 778,.World Health Organization, Geneva, 1989.

Guidelines for the safe use of wastewater and excreta in agriculture and aqua- culture. Duncan Mara and Sandy Cairncross, World Health Organization, Geneva, 1989.

The use of water for agriculture is an issue of major importance to less de- veloped countries. Wastewater is commonly used for irrigation, particularly in arid regions. In recent years the practice has increased as a means of water conservation and increasing crop production. However, the advantages of wastewater utilization need to be balanced against the hazards of infectious disease. Guidelines are required to provide public health safeguards to mini- mize health risks, when water contaminated with human wastes is applied to crops.

Health guidelines for the use of wastewater in agriculture and aquaculture is the report of a World Health Organization scientific group which concen-

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trated on the use of wastewater for agriculture, including orchards, vineyards, fiber and seed crops. Application of reclaimed water in aquaculture for fish and edible plant production is also discussed. The authors emphasize that the use of aquaculture for food crops is particularly pertinent to the economies of less developed countries.

This small handbook, one of the WHO technical report series, summarizes the views of a group of experts who met in Geneva in 1987. It is unfortunate that the report reflects the conclusions of a committee that met several years ago. Nonetheless the handbook provides a very useful guide to the epide- miological risks from wastewater use. It provides information about the path- ogens in wastewater, their survival rates, and the factors controlling disease transmission. Recommendat ions are provided for safe re-use of wastewater, including crop selection and appropriate technologies. An excellent chapter discusses unanswered questions and suggests research needs. The report is well written and should be useful to scientists, engineers and agricultural practitioners interested in re-use of wastewater.

A more detailed and definitive book on the same subject, Guidelines for the safe use of wastewater and excreta in agriculture and aquaculture was written by Duncan Mara and Sandy Cairncross and published in 1989 by the World Health Organization. The stated objective is to "encourage the safe use of wastewater and excreta in agriculture and aquaculture in a manner that pro- tects the health of the workers involved and of the public at large".

The book is extraordinarily comprehensive. It covers similar subjects to the small handbook discussed above. In addition, use of wastewater as a source of fertilizers and for soil structure improvement are discussed. Chapters are devoted to the practice of human excreta application to the land, and of other agricultural applications of re-use of human wastes. Sociocultural and envi- ronmental aspects of disease transmission by wastewater are treated in detail. The problem of exposure of agricultural workers and local residents is also addressed. The final section of the book provides a detailed analysis of meas- ures needed for planning and implementat ion of safe use of wastewater and excreta.

It is apparent that the authors have thoroughly researched these guidelines. This book provides information about every aspect of water re-use in an ef- fort to minimize the health risks. It is an essential reference for anyone con- cerned about the use of wastewater in agriculture. The authors are to be com- pl imented on a very successful effort.

Ralph Mitchell Harvard University

Cambridge, Massachusetts, USA