Book reviews 477

what plant species has caused a particular case of toxicity is

essential to prevent future cases.

In the field of human medicine, symptom-based

automatic (computer) diagnosis is increasingly being

developed. In time, the same will likely occur for veterinary

medicine, and Handbook of Toxic Plants of North America

provides the kind of information that can be used for this

purpose.

The most important similar work pertinent to North

America, also organized on the basis of symptoms of toxicity,

is: Knight, A.P., Walter, R.G., 2001. A Guide to Plant

Poisoning of Animals in North America. Teton NewMedia,

Jackson, WY, USA, 367 pp. (also available as a CD and online

by subscription or free to veterinarians at http://www.ivis.org/

signin.asp?url=http://www.ivis.org/home.asp (see textbook

section)). Knight and Walter’s guide is organized slightly

differently, and often presents somewhat different informa-

tion, and is familiar to numerous North American veterinar-

ians. While dealing basically with the same subject matter as

Handbook of Toxic Plants of North America, it would be a

mistake to choose one reference and ignore the other. By

consulting both works, the reader will likely obtain a better

idea of what plant is responsible for incidents of poisoning by

plants.

Ernest Small*

Biodiversity-National Program on Environmental Health,

Central Experimental Farm, Ottawa,

Ontario K1A OC6, Canada

*Tel.: +1 613 759 1370; fax: +1 613 759 1599

E-mail address: smalle@agr.gc.ca

(E. Small)

Available online 28 November 2006

doi:10.1016/j.agee.2006.10.006

Heavy Metal Contamination of Soil: Problems and

Remedies, I. Ahmad, S. Hayat, J. Pichtel (Eds.). SciencePublishers, Inc. Enfield, NH, USA (2005). 252 pp., Hard-

back, Price: US$ 85.00, USD, ISBN 1-57808-385-0.

Heavy metals can accumulate in the soil from industrial

and agricultural practices, creating a persistent problem

that is challenging and costly to remediate. Dealing with

heavy metal in soil systems requires an ability to predict

metal availability, to assess and mitigate potential risks

and to develop effective remediation methods where

excess heavy metal levels pose a threat to human or

ecosystem health. Heavy Metal Contamination of Soil:

Problems and Remedies outlines the scope of heavy metal

contamination, describes potential impacts of heavy metal

accumulation and discusses some established and experi-

mental methods of addressing contamination problems.

The focus is on relatively high levels of contamination,

such as that which can occur from applications of

contaminated wastes, rather than longer term low level

contamination from inputs of fertilizers and other

agricultural amendments.

The book begins with a broad overview of environmental

and health concerns related to land application of biosolids.

A range of contamination issues are covered with an

emphasis on the political and administrative considerations

rather than the scientific aspects of regulation. Based on an

evaluation of priority research areas for the US Environ-

mental Protection Agency, the author suggests more

resources need to be allocated to heavy metal studies,

considering the long-term persistence of heavy metal

contamination from long-term application of biosolids.

A good overview is also provided on the potential

benefits and drawbacks of the use of flyash on agricultural

soils, including the risk of heavy metal accumulation. Much

of the research on flyash has been conducted through pot

studies and the requirement for expanded field research is

identified. Applications of other metal-containing waste

products are addressed more narrowly, in chapters outlining

specific studies. For example, the results of a 15-year study

on the influence of long-term application of treated oil

refinery effluent on soil health indicated that crop

productivity and soil health were maintained although

there was a slow increase in heavy metal concentration in the

soil. The authors point out the need for monitoring the

impacts of application on sensitive microbial populations

and suggest potential methods of reducing the risk of

negative effects by alternating irrigation using oil refinery

effluent with irrigation using fresh water. Another chapter

presents the results of focused laboratory and field

evaluations of a specific municipal solid waste compost

to evaluate the effects on microbiological and biochemical

parameters.

The risk of impact from heavy metal contamination is

closely linked with bioavailability within a particular

environment. The importance and challenges of bioavail-

ability assessment for trace elements in soil systems are

outlined clearly in a well-referenced chapter. A variety of

methods commonly used for bioavailability assessments

are reviewed and some of the applications and associated

problems discussed. A subsequent chapter provides a

further review of factors influencing heavy metal avail-

ability in soils, followed by a description of a specific

study on the distribution Ni, Cu, Cd, Pb and Zn in soils

along a pollution gradient in the Kola Peninsula of Russia.

Changes in the soil microbial communities along the

gradient of Ni and Cu contamination indicate the

sensitivity of forest soils in the boreal regions to relatively

low levels of contaminant.

Much of the book emphasizes the interaction between

heavy metal contamination and the microbial community

in soils. Potential impacts of heavy metal contamination of

the functioning of the microbial ecosystem in the soil are

Book reviews478

described and methods of assessing metal impacts on

microbial dynamics in soils are evaluated. The need

for refinement of methods and the experimental approach

when evaluating microbial community dynamics is clearly

illustrated.

Remediation of contaminated areas is addressed in

several chapters. Bioremediation of toxic substances is

reviewed, although the majority of the chapter deals with

non-metallic substances that can be degraded with only brief

coverage of bioremediation of heavy metal contamination.

A comprehensive chapter describes the various mechanisms

by which microbially mediated processes may directly and

indirectly affect heavy metal availability and outlines the

practical implications for dealing with contamination by

using microbial methods to affect availability. This provides

a good summation of available references on this subject.

Another well-referenced review of current experience in

phytoremediation of lead contaminated sites also provides a

discussion of the principles that relate to remediation of

other metals.

The introduction of the book indicates that the objective

was to incorporate both theoretical and practical aspects of

the subject matter and provide baseline information for

future research. The authors have provided a good

compilation of information that should be useful to students

and researchers working in environmental and soil science.

Cynthia Grant*

Agriculture and Agri-Food Canada,

Brandon Research Centre,

Box 1000A, R.R.#3, Brandon,

Manitoba, Canada R7A 5Y3

*Tel.: +1 204 578 3570

E-mail address: cgrant@agr.gc.ca

Available online 8 December 2006

doi:10.1016/j.agee.2006.10.008

Ethnobotany: A Methods Manual, G.J. Martin. Earth-

scan, London, United Kingdom (2004). 268 pp., softback,

U.K. £24.95, ISBN: 1-84407-084-0

Ethnobotany is concerned with how different cultural

groups perceive, use and manage plants. It is a field-based

area of inquiry, and most studies have been carried out

among ‘‘traditional’’ peoples in rural settings. Ethnobota-

nical research, apart from being fascinating in its own right,

also has significant practical value, particularly when

conducted in collaboration with local people and directed

towards community development and the conservation of

biodiversity. Ethnobotany: A Methods Manual is a very

useful resource for people wishing to engage in this work.

The purpose of the manual is to describe the basic concepts,

methods and techniques of ethnobotanical data collection

and analysis, and is meant for a broad audience of people

new to the field.

The first chapter focuses on research design and includes

a section on rapid ethnobotanical appraisal. As the author

stresses, ethnobotany is a multidisciplinary enterprise, and

most of the remainder of the book is organized into chapters

focusing on six individual fields—botany, ethnopharmacol-

ogy, anthropology, ecology, economics and linguistics. Each

of these chapters describes key concepts, methods and

procedures. For example, the botany chapter discusses the

various ways of collecting and preparing herbarium speci-

mens. The next chapter, on ethnopharmacology, provides an

overview of phytochemical analysis and different screening

techniques. The anthropology chapter discusses interview

techniques as well as other ethnographic research methods,

and provides good advice for interviewers on how to build

rapport and avoid inappropriate behaviour. Successive

chapters cover, among other things, quadrat sampling,

measuring plant diversity, calculating the economic value of

a forest, conducting a survey of local markets, and

investigating folk classification systems.

One of the strengths of this book is that is provides a

wide-ranging overview and a description and discussion of a

broad array of terms and concepts, including everything

from spirit collections, seed banks, secondary metabolites,

belt transects, relative dominance and maximum sustainable

yields, to discount rates, net present value, toponyms, emic

categories, phonemes, humoral properties, over-differen-

tiated classification and intellectual property rights. Martin

also consistently points out the advantages, disadvantages

and potential pitfalls of different methods, and their

suitability in different contexts—in short, he gives a lot

of good advice for novices, drawing from extensive personal

experience. He also includes numerous examples to

illustrate how methods are actually carried out in the field.

The only limitation here is that the collection of cases is not

well balanced. Most come from tropical forest regions,

particularly Mexico. Overall, the book neglects methodo-

logical issues of greater relevance to cold, temperate and arid

environments.

This manual has two significant limitations. In the first

place, there is an overemphasis on the classification and use

of plants, and very little on local knowledge of plant ecology.

Indigenous peoples have detailed understanding of such

things as how crops are affected by different environmental

conditions, phenologies, pollination, herbivory and seed

dispersal mechanisms. If a primary purpose of ethnobotany

is to inform and promote community-based conservation,

this type of local knowledge – and how it influences local

management practices – is of critical importance. Another

weakness is an overemphasis on quantitative research

methods. The book includes extensive sections describing

statistical methods, ranking systems, matrixes, indices and

various other measures. In contrast, while there is some

discussion of ethnobotanical information found in myths and