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Selenium is a naturally occurring trace element that can become concentrated and released by industrial, agricultural, petrochemical and mining activities. At concentrated levels it is toxic and has polluted ecosystems around the world. This book will serve as a comprehensive practical handbook for everyone dealing with selenium in aquatic environments. It offers field-tested approaches and methods for assessment and water quality management. Using his twenty-year experience, the author discusses the effects of selenium on fish and bird populations and presents guidelines for identifying sources of pollution, interpreting selenium concentrations, assessing hazardous conditions, setting water quality criteria and ecosystem loading limits (TMDLs). He also includes a procedure for setting environmentally safe limits that ensure compliance with EPA regulations. Selenium Assessment in Aquatic Ecosystems will interest field scientists, natural resource managers, risk assessors and environmental planners.
The purpose of this study is to better understand the essential interdependencies between the world economy and the global ecosystem, including human populations. World production, product prices, wages, interest rates, exchange rates, employment, and spending are shown to be mutually determined over time with the growth rates of country-specific renewable resources, the generation of waste, human population growth, waste assimilation by the basic fungible resource, and the sanitation and other health and human services provided by the government sectors. Particular attention is paid to alternative central bank policies and their potential effects upon future mixes of resources in world production and upon the level and composition of that production. Materials balance holds with respect to all production and consumption. Cash flow constraints hold with respect to all economic transactions; in particular, the decisions to save and invest are directly linked to financial market decisions.
The presence - or absence - of soil organic matter (SOM) has important implications for agricultural productivity. It could also have significant implications for global climate due to its role as a source/sink of carbon. Therefore, it is important to understand the issues related to the accumulation or loss of SOM, to use what we have learned from experiments to make sound decisions about soil and crop management, and to test models and future concepts concerning SOM management. A database is included with the book, presenting tabular data for 34 sites in North America.
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