Author
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Olness, Alan |
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Submitted to: Soil Science
Publication Type: Review Article Publication Acceptance Date: 7/1/2004 Publication Date: 8/1/2004 Citation: Olness, A.E. 2004. Humic substances: Nature's most versatile materials. Soil Science. 169(8):611-612. Interpretive Summary: Technical Abstract: Humic substances, natural organic material in soil and water, are some of the most complex materials found in the environment. Their characterization remains one of science's most intriguing challenges. Twenty-four papers presented at the Humic Substances Seminar VI held at Northeastern University and at the immediately preceding IHSS 11 (the 20th anniversary meeting) Conference also held at Northeastern University are collected in this volume. The text is segmented into four sections. In part I, titled Fractionation and characterization: The state-of-the-art, examples of application of the most advanced technologies are discussed. These include capillary electrophoresis-electrospray/mass spectrometry (CZ-ESI-MS), asymmetrical flow field-flow fractionation (AFFFF), time of flight secondary ion mass spectrometry (TOF-SIMS), use of radioactive tracers with high performance size exclusion chromatography and ultrahigh resolution electrospray ionization Fourier transform-ion cyclotron resonance masspectrometry (ESI FT-ICR MS). In part II, the hydration, swelling and sorption characteristics of these challenging materials are discussed. These include sorption of polyaromatic hydrocarbons, some of the more metabolically resistant compounds, and the common herbicides of atrazine and 2,4-dichlorophenoxyacetic acid by humic substances and humic-clay or metal oxide complexes. This section also illustrates the capacity of humic substances to mitigate the concentrations and effects of a variety of xenobiotic compounds. Part III focuses on humic substance-metal interactions and the effects of humic substances on the relative mobility and environmental consequences of these materials. Trace metal complexation of metals, especially "heavy metals" and those in the lanthanide and actinide series, have been a focus for scientists working with humic substances for decades. It is clear from the collection of papers in this section that humic substances make a measurable and important contribution to the geochemical mobility and cycling of these elements. Papers in this section range from very basic ion-binding studies to the role of humic substances in movement and migration of a number of elements and include a discussion of the catalytic effects of complexes on other chemical processes. The book closes with two papers in part 4 detailing the effects of humic substances on physiology of aquatic plants and evidence for humic substances serving as sources for a variety of elements to aquatic plants. While many of the complexes inhibit plant growth, a few are clearly growth promoters and many have measurable effects on specific enzyme systems. Humic substances cause changes in the effective concentrations of a number of elements and these changes are clearly manifested in the measurements presented. The number of technical terms and concepts in the various papers make this a suitable acquisition for advanced undergraduates and those having a master's degree in the sciences. The papers contain a number of complex figures and the reproduction has been quite good for most of them. Technical production and editing of the text is excellent. A few illustrations would have been better produced in color because the shades of gray provide insufficient distinction to make subtle features easily detectable. It is unfortunate that more of the provocative papers presented at the 11th biennial conference of the International Humic Substances Society meetings were not included in this volume. The content of that conference was outstanding and the text of this volume provides only a glimpse of the real progress being made in the understanding of humic substances. The length, 369 pages, is brief for such a complex subject and the suggested retail price of $110.00 is reasonable. |
