The research papers in this text were presented as part of the Fourth International Conference on the Biogeochemistry of Trace Elements. The purpose of the conference was to present late-20th century knowledge of the sources, pathways, behaviour and effects of trace elements in soils, waters, plants and animals. The book is intended for a variety of readers, including public health and environmental professionals, industrial hygienists, consultants, waste management professionals, and academics. It may also prove valuable to scientists conducting research on coal and coal combustion byproducts.