Human Viruses in Sediments, Sludges, and Soils [antikvár]

I. INTRODUCTION This chapter is for those who are unfamiliar with the nature of sediments, sludges, and soils. It is important to understand the principles governing the interactions of these materials with humán viruses for the development of methods in virus recovery and in studies relating to virus persistence and inactivation. The relationship of these materials to the water environment has been studied for years by geologists, soil scientists, and environmental engineers. These disciplines have developed a vocabulary for describing the physical and chemical properties of the materials. The vocabulary terms are carefully explained so that a concept of the meaning is established. Somé examples are used to illustrate the principles involved. Finally, the relevance of the materials to the environment is explored. Our ignorance of the complexities and nature of the interactions is manifest. The simplistic way many things are described is a mask for our ignorance. Much work is ahead for a more complete understanding of the science. References are liberally used so that the subject matter can be explored more deeply. II. PHYSICAL, CHEMICAL, AND BIOLOGICAL CHARACTERISTICS OF SEDIMENTS A. Sediment Classification Sediment is solid matter suspended in or deposited from a liquid by physical, chemical, or biological agents. Physical or clastic sediments are eroded solid materials from preexisting rock mechanically transported and deposited by wind, water, or ice in response to gravity. They are generally classified by mineral composition, texture, mass properties, and chemical composition. Nonclastic sediments are förmed by chemical and biological processes from material in solution. Chemical sediments are primarily precipitates from water. Chemical sediments are classified by chemical processes, pH, EH, weathering, and inorganic chemical processes. Biological sedimentation results from interactions involving sediments and organisms. Biological sediment classifications include secretion and degradation of calcium carbonate skeletons, trapping and baffling of sedimentary particles by organisms, pelletization, burrowing, and various effects of microorganisms.1