Preface.- Contributors.- List of Abbreviations.- Section 1: Basic Principles: Introduction.-Sources of Heavy Metals and Metalloids in Soils.- Chemistry of Heavy Metals and Metalloids in Soils.- Methods for the Determination of Heavy Metals and Metalloids in Soils.- Effects of Heavy Metals and Metalloids on Soil Organisms.- Soil-Plant Relationships of Heavy Metals and Metalloids.- Heavy Metals and Metalloids as Micronutrients for Plants and Animals.-Critical Loads of Heavy Metals for Soils.- Section 2: Key Heavy Metals And Metalloids: Arsenic.- Cadmium.- Chromium and Nickel.- Cobalt and Manganese.- Copper.-Lead.- Mercury.- Selenium.- Zinc.- Section 3: Other Heavy Metals And Metalloids Of Potential Environmental Significance: Antimony.- Barium.- Gold.- Molybdenum.- Silver.- Thallium.- Tin.- Tungsten.- Uranium.- Vanadium.- Glossary of Specialized Terms.- Index.

Heavy metals in soils : trace metals and metalloids in soils and their bioavailability

Halloysite clay minerals are ubiquitous in soils and weathered rocks where they occur in a variety of particle shapes and hydration states. Diversity also characterizes their chemical composition, cation exchange capacity and potassium selectivity. This review summarizes the extensive but scattered literature on halloysite, from its natural occurrence, through its crystal structure, chemical and morphological diversity, to its reactivity toward organic compounds, ions and salts, involving the various methods of differentiating halloysite from kaolinite. No unique test seems to be ideal to distinguish these 1:1 clay minerals, especially in soils. The occurrence of 2:1 phyllosilicate contaminants appears, so far, to provide the best explanation for the high charge and potassium selectivity of halloysite. Yet, hydration properties of the mineral probably play a major role in ion sorption. Clear trends seem to relate particle morphology and structural Fe. However, future work is required to understand the possible mechanisms linking chemical, morphological, hydration and charge properties of halloysite.

Halloysite clay minerals — a review

Adsorption of proteins from solution at the solid-liquid interface.

Surface area control of organic carbon accumulation in continental shelf sediments

http://andrewsforest.oregonstate.edu/pubs/pdf/pub1781.pdf

Relationships between mineral surfaces and organic carbon concentrations in soils and sediments

Effects of drying and heating on the surface area of allophane and imogolite

It is well established that the presence of clay in an enzyme-substrate system may reduce the activity of enzymes (1-3,5,6,8,11-14). This inhibition by the clay would be principally caused by the adsorption of enzyme and/or substrate on the clay particle. In the previous papers (1–3), the activity of some enzymes was found to be inhibited in various degrees by clays. The enzyme appears to be adsorbed on the clay particle in various ways according to the nature of adsorbate as well as adsorbent. This suggests that the enzyme is adsorbed by the clay so as not to combine with the substrate, or that the adsorbed enzyme molecule has a configuration different from that of a free enzyme molecule, reducing the activity of the enzyme.

https://www.tandfonline.com/doi/pdf/10.1080/00380768.1967.10431995

Mechanism of inhibitory effect of allophane and montmorillonite on some enzymes

A distinct, brownish yellow soil layer often intervenes between dark colored layers in the profiles of Ando soil in Kyushu, particularly in central east and southern Kyushu The layer is called “imogo” in the Hitoyoshi district and “akahoya” in the Miyazaki district The soil is characterized by a very low bulk density such as 04, and bears glassy particles in abundance, which are colorless and shard-shaped It often displays exchange-neutrality or exchange-alkalinity Plant roots are very few in the layer, and most roots are observed to make a bend along the layer surface, from perpendicular to horizontal It seems that the plant root has trouble intruding the layer, probably because of its special structure (1, 2)

https://www.tandfonline.com/doi/pdf/10.1080/00380768.1965.10431167

Imogolite of Imogo-Layers in Kyushu

White concretions and coatings have been found in weathered volcanic sand and gravel layers at Kuroishibaru Branch of Kyushu Agricultural Experiment Station. Their identity has been questioned by attendants to the field trip of the FAO Soil Correlation Meeting on volcanic ash soils in June, 1964. This paper reports results of urineral identification of these concretions and coatings together with associated weathering products. It also includes those of the comparative analyses of one of the upper volcanic ash layers in which gibbsite accumulates to a greater extent.

Occurrence of gibbsite in weathering of volcanic materials at Kuroishibaru, Kumamoto

Volcanic ash solis in Japan are remarkably high in humus content irrespective of climate or drainage. They are sometimes as high as 20 per cent or more in organic carbon content. This fact has led to a presumption that allophane would be retentive of organic matter (3, 8–11, 21). However, there is a few experimental evidence suggesting that allophane provides a great protection for organic matter against microbial activity. Aomine and Kodama (3) presented data that the rate of breakdown of cellulose or albumin by soil microorganisms was noticeably lower in an allophanic clay of Ando soil than an illitic or montmorillonitic clay of alluvial soils. Harada (8) showed a slow decomposition of albumin in an Ando paddy soil and its low effectiveness for rice crop as compared with ammorrium sulfate in the same soil. Jackman (9) suggested two possibilities for the stabilization of organic matter by allophane: an unusualIy strong adsorption of organic matter which is thereby protected from microbial attack...

Shigenori Aomine

Papers

Effects of drying and heating on the surface area of allophane and imogolite

Mechanism of inhibitory effect of allophane and montmorillonite on some enzymes

Imogolite of Imogo-Layers in Kyushu

Occurrence of gibbsite in weathering of volcanic materials at Kuroishibaru, Kumamoto

Effecfs of allophane on the enzymatic activity of a protease