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

Mercury is one of the most hazardous contaminants that may be present in the aquatic environment, but its ecological and toxicological effects are strongly dependent on the chemical species present. Species distribution and transformation processes in natural aquatic systems are controlled by various physical, chemical, and biological factors. Depending on the prevailing environmental conditions, inorganic mercury species may be converted to many times more toxic methylated forms such as methylmercury, a potent neurotoxin that is readily accumulated by aquatic biota. Despite a considerable amount of literature on the subject, the behavior of mercury and many of the transformation and distribution mechanisms operating in the natural aquatic environment are still poorly understood. This review examines the current state of knowledge on the physicochemical behavior of mercury in the aquatic environment, and in particular the environmental factors influencing its transformation into highly toxic methylated forms.

Mercury in the Aquatic Environment: A Review of Factors Affecting Methylation

Marine biogeochemical cycling of mercury.

PROBLEM TO BE SOLVED: To perform molecular weight measurement and separation of a fluorine containing organic substance slightly soluble in a general organic solvent by means of size exclusion chromatography by using a solvent containing dichloro pentafluoropropane as a mobile phase and using polymethyl methacrylate with a known molecular weight as a molecular weight measurement standard specimen. SOLUTION: As a mobile phase. a solvent containing HCFC225 such as a solvent containing only HCFC225 and a mixture solvent containing HCFC225 and other solvents are available. HCFC225 is selected from one or more kinds of substances selected from chlorinated fluorinated hydrocarbons with a molecular formula represented by C3 HF3 Cl2 . As the HCFC225, several kinds of isomers with the same molecular formula and different structures are known, however, HCFC225ca (CF3 CF2 CHCl2 ), HCFC225cb (CF2 ClCF2 CFHC1), and a mixture of them are desirable. As a molecular weight measurement standard specimen, polymethyl methacrylate with a known molecular weight is used.

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Size Exclusion Chromatography

Remediation of mercury contaminated sites - A review

Mercury contamination in the Yatsushiro Sea, south-western Japan: Spatial variations of mercury in sediment

Sediments collected from Kagoshima Bay, Minamata Bay and Yatsushiro Sea were analyzed for organic mercury, mercury(II) oxide, mercury(II) sulfide and residual mercury through sequential extraction followed by cold vapor atomic absorption spectrometry. Results show that mercury(II) sulfide (38.4∼96.1%, geometric mean 71.4%) is the most prevalent mercury compound in the sediments followed by mercury(II) oxide (<0.9∼42.9%, geometric mean 5.65%). Organic mercury is present only in a very small quantity (0.21∼12.8%, geometric mean 2.55%). Residual mercury shows a wide range of content in the sediments (2.6∼44.3%, geometric mean 10.5%). The abnormally high mercury concentration observed in the sediment samples from Northern Kagoshima Bay is caused by the condensation of submarine fumarolic gases including elemental mercury and hydrogen sulfide, which are depositing in the surface sediments. This is in accord with the fact that mercury(II) sulfide is the most prevalent mercury compound there. Organic mercury content is high in the vicinity of the submarine fumarole, where mercury(II) sulfide content is very high.

The contents and chemical forms of mercury in sediments from Kagoshima Bay, in comparison with Minamata Bay and Yatsushiro Sea, southwestern Japan

A method has been proposed for the differential determination of mercury compounds in sediments, based on their successive extraction followed by a cold vapor atomic absorption spectrometric (CVAAS) determination. Organic mercury was first extracted by shaking a sediment sample with chloroform. The mercury in the extract was subsequently back-extracted into a 0.01M sodium thiosulfate solution. In order to separate mercury(II) oxide from mercury(II) sulfide, the residue was treated with 0.05M sulfuric acid so as to extract only mercury(II) oxide. Mercury(II) sulfide was finally extracted from the residue with 1M hydrochloric acid containing 3% sodium chloride in the presence of copper(I) chloride. The mercury in each extract was determined by CVAAS. When artificial standard sediment samples spiked with a given amount of each mercury compound were successively treated by the above-mentioned procedures, the recoveries of organic mercury, mercury(II) oxide and mercury(II) sulfide were 99.9, 99.5 and 98.2%, respectively. This method was successfully applied to a differential determination of mercury compounds in marine sediments.

Differential Determination of Organic Mercury, Mercury(II) Oxide and Mercury(II) Sulfide in Sediments by Cold Vapor Atomic Absorption Spectrometry.

Background levels of atmospheric mercury in Kagoshima City, and influence of mercury emission from Sakurajima Volcano, Southern Kyushu, Japan

The contents and distributions of arsenic, antimony, and mercury in geothermal water samples taken from various geothermal areas in Japan were investigated. Since the existing forms of arsenic, antimony, and mercury in geothermal waters are complex and can change during sample storage, it is difficult to determine all of the chemical forms. In this study, therefore, the arsenic(III+V), antimony(III+V), and total mercury contents were determined. In geothermal water, there is a high positive correlation between the contents of arsenic and antimony. However, there is no correlation at all between the contents of mercury and arsenic, or between those of mercury and antimony. It can be assumed that mercury behaves differently from either arsenic or antimony in geothermal water.

Norinobu Yonehara

Papers

Mercury contamination in the Yatsushiro Sea, south-western Japan: Spatial variations of mercury in sediment

The contents and chemical forms of mercury in sediments from Kagoshima Bay, in comparison with Minamata Bay and Yatsushiro Sea, southwestern Japan

Differential Determination of Organic Mercury, Mercury(II) Oxide and Mercury(II) Sulfide in Sediments by Cold Vapor Atomic Absorption Spectrometry.

Background levels of atmospheric mercury in Kagoshima City, and influence of mercury emission from Sakurajima Volcano, Southern Kyushu, Japan

The contents and distributions of arsenic, antimony, and mercury in geothermal waters