Effects of acid precipitation on terrestrial ecosystems

85 effects, requirements, levels in soft, water and food-stuffs, identification of deficiency and exposure, industrial and urban emissions. (ii) to draw up recommendations for further research. The proceedings are published as t w o separate books, the first containing 34 individual papers on As and the second 54 papers on Ni, generally of 6--7 pages in length. The specific subjects discussed on As provide a sound basis on the essentiality and toxicity of As while lack of a clear basis exists regarding some fundamental questions such as the carcinogenicity of As to lung, the final conclusions indicating that "this effect has probably been overestimated". With regard to nickel the most striking aspect of the papers presented is an indication that primary Ni-deficiency might not occur in livestock and humans; the suggested requirement of the element being of the order of 500 ppb. Another important aspect is the carcinogenicity of Ni c o m p o u n d s considered an undisputed question depending on the kinetics of their dissolution and removal from the injection site. Open questions requiring further investigations include studies on the biochemical mechanisms for Ni deficiency and intoxication, a better determination of the "normal levels" in animals and human tissues as well as in food-stuffs and the eventual teratogenic effect of Ni. These books would be useful for environmental toxicologists and industrial hygienists and can also have a direct relevance in medicine, agriculture and analytical chemistry research.

Ispra ( Varese ) (Italy)

E. Sabbioni

Effects of Acid Precipitation on Terrestrial Ecosystems, edited b y T. C. Hutchinson and M. Havas (NATO Conference Series, Series 1: Ecology, Volume 4) Plenum Publishing Corp. New York, N.Y., 1980, 654 pp. Price: US $ 49.50. This imposing volume contains the 38 papers presented at a NATO Advanced Research Institute on the "Effects of Acid Precipitation on Vegetation and Soils", held at Toronto, Canada from May 22 to 26, 1978, specifically to bring together international experts to present, examine and discuss the scientific research relevant to freshwater and terrestrial systems. The soil and its biota are a wonderfully complex system. This symposium was organized to examine our scientific knowledge of the normal functioning of terrestrial ecosystems and the presently d o c u m e n t e d effects of acid precipitation on this functioning. While a further spread of acidified lakes seems presently very probable, a good deal of concern has been expressed a b o u t the health of our terrestrial ecosystems and the susceptibility of forests and agricultural crops to acid precipitation. Over much of the regions receiving acid rains and acid snowmelt water, the softs are and have been naturally

86 acidic. The natural farming practices in higher rainfall areas are to compensate for nutrient leaching and development of acidity b y liming and fertilising. In forests, the majority of plants are long lived perennials so that, unless effects of acid precipitation are dramatic and severe, changes will be slow and perhaps masked b y the natural annual fluctuations in climate. The presentations generally follow the course of the acid rain or snow from the atmosphere (8 papers) to the foliage of the plants, thence the soil (11 papers); through the soil either to influence plant nutrition through r o o t uptake and microbial interaction (10 papers); or via drainage from the soil to watershed streams and rivers to the lakes (9 papers). A conference, and its presentation in a volume, may generally be appraised following a pattern. 1. Subject matter. This should be: (a) homogeneous; (b) comprehensive as far as the topic goes; and (c) free of titles, papers, accepted o u t of complacence, or for reasons of respect for some author or sponsor. This volume deserves the highest rating on all of these points. 2. Treatment. The papers should be pertinent, n o t overlong and nevertheless with enough detail, b o t h for the specialist and for occasional perusal. The volume makes the best possible impression concerning this point also. 3. Explicitness of the results and identification of unsolved problems. The volume is concluded by 10 summaries drawn up by rapporteurs (about 25 pages in all) which quite successfully play the role of what generally is called an executive summary. They also take into account essentials of the observations and criticism voiced during the debates. People who do not need the details and concentrate only on the highlights and the findings or look for controversial points, will save time b y reading these summaries only or first. The finishing touch to these summaries is provided b y T. C. Hutchinson, in the Conclusions and Recommendations, a chapter which is the keystone of the volume. The areas of consensus are being clearly delimited and recommendations for research are concisely and strikingly worded. 4. Presentation. It seems that the papers have been re-typed uniformly and reproduced from this camera-ready copy. The correction of typographical errors is usually a major problem with this procedure. In this volume, I could not locate a single one. The print is pleasing, easy to read; the graphs are clear and the esthetics of the presentation exemplary. A species index and a subject index conclude the volume. General appreciation is based on the above four points, including the subheadings: an enviable standard has been set which will be difficult to surpass. The bulk and the price notwithstanding, this volume is a worthwhile acquisition for a wide variety of scientists in the whole environmental field.

Brdtigny (France)

Michel Benarie