No abstract

No abstract

Cover illustration: Courtesy of Dr. Laura Janecek and Mr. David Scott (SREL), an awardwinning photographer. Library of CongressCataloging-in-Publication Data Adriano, D.C. Trace elements in terrestrial environments: biogeochemistry, bioavailability, and risks of metals/Domy C. Adriano.-2nd ed. p. cm. Rev. ed. of: Trace elements in the terrestrial environment. c1986. Includes bibliographical references. ISBN 978-1-4684-9505-8 I. Trace elements-Environmental aspects. 2. Trace elements in nutrition. 3. Biogeochemical cycles. 1. Adriano, D.C. Trace elements in the terrestrial environment. II. Title.

The impact of mining and smelting of metal ores on environmental quality is described. Mines produce large amounts of waste because the ore is only a small fraction of the total volume of the mined material. In the metal industry, production of Cu, Pb, and Zn causes the greatest degradation of the environment. Copper mining produces extensive mine wastes and tailings and Cu smelting emits approximately 0.11 Mg of S per Mg of Cu produced in the USA. Zinc and Pb smelters release large quantities of Cd and Pb into the environment. Metal smelting and refining produce gaseous (CO2, SO2, NOx, etc.) and particulate matter emissions, sewage waters, and solid wastes. Soil contamination with trace metals is considered a serious problem related to smelting; however, mining and smelting are not main sources of global metal input into soils. Other sources like discarded manufactured products, coal ash, agriculture, and transportation take a lead. Smelters are the main sources of atmospheric emissions of As, Cu, Cd, Sb, and Zn on a global scale and they contribute substantially to the overall emissions of Cr, Pb, Se, and Ni. A quantitative evaluation of the environmental health effects of mining and smelting is difficult because of the complexity of factors involved and lack of consistent methodology. Nevertheless, the case studies described indicate that negative health effects could arise from Pb mining and smelting. Risk assessment revealed that food chain contamination by Cd from soils contaminated by smelting is very unlikely under the western diet.

No abstract

No abstract

Coal combustion residues account for 90% of all fossil fuel combustion wastes produced in the USA. It is projected that by the year 2000 more than 150 million t of these materials will be produced in the USA each year. Presently, only about 20% of these wastes are utilized, with the remainder deposited in landfills or surface impoundments. This article reviews the information available concerning the environmental impacts associated with the disposal or utilization of coal combustion residues. The majority of the information available in the literature concerns the impacts of fly and bottom ashes; other coal combustion wastes have not received much attention. The major potential impacts of ash disposal on terrestrial ecosystems include: leaching of potentially toxic substances into soils and groundwater; reductions in plant establishment and growth due primarily to adverse chemical characteristics of the ash; changes in the elemental composition of vegetation growing on the ash; and increased mobility and accumulation of potentially toxic elements throughout the food chain. Ash disposal in landfills and settling ponds can influence adjacent aquatic ecosystems directly, through inputs of ash basin effluent and surface runoff, and indirectly, through seepage and groundwater contamination. Major impacts are generally associated with changes in water chemistry, including changes in pH and concentrations of potentially toxic elements. Using ash as a soil amendment can improve soil texture and water‐holding capacity, increase soil pH, and enhance soil fertility. However, it may also result in excessive soluble salt concentrations, excess B, and increased concentrations of other potentially toxic trace elements; reduction in the concentrations and/or availability of soil N and P; elemental imbalances due to excessively high pH; and cementation or compaction of soil. Scrubber sludge and fluidized bed combustion waste may be used as soil amendments as well, but also may create problems due to high alkalinity and high salinity.

No abstract