The chemical composition of natural water is derived from many different sources of solutes, including gases and aerosols from the atmosphere, weathering and erosion of rocks and soil, solution or precipitation reactions occurring below the land surface, and cultural effects resulting from human activities. Broad interrelationships among these processes and their effects can be discerned by application of principles of chemical thermodynamics. Some of the processes of solution or precipitation of minerals can be closely evaluated by means of principles of chemical equilibrium, including the law of mass action and the Nernst equation. Other processes are irreversible and require consideration of reaction mechanisms and rates. The chemical composition of the crustal rocks of the Earth and the composition of the ocean and the atmosphere are significant in evaluating sources of solutes in natural freshwater. The ways in which solutes are taken up or precipitated and the amounts present in solution are influenced by many environmental factors, especially climate, structure and position of rock strata, and biochemical effects associated with life cycles of plants and animals, both microscopic and macroscopic. Taken together and in application with the further influence of the general circulation of all water in the hydrologic cycle, the chemical principles and environmental factors form a basis for the developing science of natural-water chemistry. Fundamental data used in the determination of water quality are obtained by the chemical analysis of water samples in the laboratory or onsite sensing of chemical properties in the field. Sampling is complicated by changes in the composition of moving water and by the effects of particulate suspended material. Some constituents are unstable and require onsite determination or sample preservation. Most of the constituents determined are reported in gravimetric units, usually milligrams per liter or milliequivalents

Study and Interpretation of the Chemical Characteristics of Natural Water

The major source of cloud-condensation nuclei (CCN) over the oceans appears to be dimethylsulphide, which is produced by planktonic algae in sea water and oxidizes in the atmosphere to form a sulphate aerosol Because the reflectance (albedo) of clouds (and thus the Earth's radiation budget) is sensitive to CCN density, biological regulation of the climate is possible through the effects of temperature and sunlight on phytoplankton population and dimethylsulphide production. To counteract the warming due to doubling of atmospheric CO2, an approximate doubling of CCN would be needed.

Oceanic phytoplankton, atmospheric sulphur, cloud albedo and climate

This book describes the present state of knowledge regarding the impact of cyanobacteria on health through the use of water. It considers aspects of risk management and details the information needed for protecting drinking water sources and recreational water bodies from the health hazards caused by cyanobacteria and their toxins. It also outlines the state of knowledge regarding the principal considerations in the design of programmes and studies for monitoring water resources and supplies and describes the approaches and procedures used.
The development of this publication was guided by the recommendations of several expert meetings concerning drinking water (Geneva, December 1995; Bad Elster, June
1996) and recreational water (Bad Elster, June 1996; St Helier, May 1997). An expert meeting in Bad Elster, April 1997, critically reviewed the literature concerning the toxicity of cyanotoxins and developed the scope and content of this book. A draft manuscript was reviewed at an editorial meeting in November 1997, and a further draft was
reviewed by the working group responsible for updating the Guidelines for Drinkingwater Quality in March 1998.

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Toxic cyanobacteria in water: a guide to their public health consequences, monitoring and management.

The chemical composition of subducting sediment and its consequences for the crust and mantle

Virtually all nonequilibrium electron transfers on Earth are driven by a set of nanobiological machines composed largely of multimeric protein complexes associated with a small number of prosthetic groups. These machines evolved exclusively in microbes early in our planet's history yet, despite their antiquity, are highly conserved. Hence, although there is enormous genetic diversity in nature, there remains a relatively stable set of core genes coding for the major redox reactions essential for life and biogeochemical cycles. These genes created and coevolved with biogeochemical cycles and were passed from microbe to microbe primarily by horizontal gene transfer. A major challenge in the coming decades is to understand how these machines evolved, how they work, and the processes that control their activity on both molecular and planetary scales.

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The Microbial Engines That Drive Earth's Biogeochemical Cycles

This extensively updated new edition of the widely acclaimed Treatise on Geochemistry has increased its coverage beyond the wide range of geochemical subject areas in the first edition, with five new volumes which include: the history of the atmosphere, geochemistry of mineral deposits, archaeology and anthropology, organic geochemistry and analytical geochemistry. In addition, the original Volume 1 on "Meteorites, Comets, and Planets" was expanded into two separate volumes dealing with meteorites and planets, respectively. These additions increased the number of volumes in the Treatise from 9 to 15 with the index/appendices volume remaining as the last volume (Volume 16). Each of the original volumes was scrutinized by the appropriate volume editors, with respect to necessary revisions as well as additions and deletions. As a result, 27 per cent were republished without major changes, 66per cent were revised and 126 new chapters were added. In a many-faceted field such as Geochemistry, explaining and understanding how one sub-field relates to another is key. Instructors will find the complete overviews with extensive cross-referencing useful additions to their course packs and students will benefit from the contextual organization of the subject matter. Six new volumes added and 66per cent updated from 1st edition. The Editors of this work have taken every measure to include the many suggestions received from readers and ensure comprehensiveness of coverage and added value in this 2nd edition. The esteemed Board of Volume Editors and Editors-in-Chief worked cohesively to ensure a uniform and consistent approach to the content, which is an amazing accomplishment for a 15-volume work (16 volumes including index volume)!

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Treatise on geochemistry

In this first full-scale attempt to reconstruct the chemical evolution of the Earth's atmosphere and oceans, Heinrich Holland assembles data from a wide spectrum of fields to trace the history of the ocean-atmosphere system A pioneer in an increasingly important area of scholarship, he presents a comprehensive treatment of knowledge on this subject, provides an extensive bibliography, and outlines problems and approaches for further research The first four chapters deal with the turbulent first half billion years of Earth history The next four chapters, devoted largely to the Earth from 39 to 06 bybp, demonstrate that changes in the atmosphere and oceans during this period were not dramatic The last chapter of the book deals with the Phanerozoic Eon; although the isotopic composition of sulfur and strontium in seawater varied greatly during this period of Earth history, the chemical composition of seawater did not

The chemical evolution of the atmosphere and oceans

Several lines of geological and geochemical evidence indicate that the level of atmospheric oxygen was extremely low before 2.45 billion years (Gyr) ago, and that it had reached considerable levels by 2.22 Gyr ago. Here we present evidence that the rise of atmospheric oxygen had occurred by 2.32 Gyr ago. We found that syngenetic pyrite is present in organic-rich shales of the 2.32-Gyr-old Rooihoogte and Timeball Hill formations, South Africa. The range of the isotopic composition of sulphur in this pyrite is large and shows no evidence of mass-independent fractionation, indicating that atmospheric oxygen was present at significant levels (that is, greater than 10-5 times that of the present atmospheric level) during the deposition of these units. The presence of rounded pebbles of sideritic iron formation at the base of the Rooihoogte Formation and an extensive and thick ironstone layer consisting of haematitic pisolites and oolites in the upper Timeball Hill Formation indicate that atmospheric oxygen rose significantly, perhaps for the first time, during the deposition of the Rooihoogte and Timeball Hill formations. These units were deposited between what are probably the second and third of the three Palaeoproterozoic glacial events.

Dating the rise of atmospheric oxygen

The last 3.85Gyr of Earth history have been divided into five stages. During stage 1 (3.852.45Gyr ago (Ga)) the atmosphere was largely or entirely anoxic, as were the oceans, with the possible exce...

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The oxygenation of the atmosphere and oceans

tion. The third major section of the book introduces the field of river quality. Brief reviews are provided for sediment and heat as pollutants and for the extensive topic of chemical water quality, empha sizing biodegradable wastes and the oxy gen balance in stream water. This is fol lowed by a useful discussion of stream biota as indicators of stream health. The book ends with a chapter on the evalua tion of river esthetics which updates Leopold's well-known graphical analysis procedure. Even Hercules had a few weaknesses: he was, after all, perceived as only partly a god. In this text the shortcomings are likewise minimal. I would have preferred a more extensive analysis of ground water, which receives about 60% as much treat ment as river channels. Brief treatment is also afforded the important problem of trace metals in water, and sanitary landfill hydrogeology is essentially ignored. However, these are minor defects in a text that can be strongly recommended, and it is a pleasure to report that the publisher has produced a high-quality volume worthy of the scholarship of its au thors.-Victor R. Baker, Geological Sci ences, University of Texas

Heinrich D. Holland

Papers

Treatise on geochemistry

The chemical evolution of the atmosphere and oceans

Dating the rise of atmospheric oxygen

The oxygenation of the atmosphere and oceans

The chemistry of the atmosphere and oceans