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ENERGY MODEL OF A CADMIUM STREAM WITH CORRELATION OF EMBODIED ENERGY AND TOXICITY
Citation:
Knight, R. ENERGY MODEL OF A CADMIUM STREAM WITH CORRELATION OF EMBODIED ENERGY AND TOXICITY. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/3-82/048.
Description:
In surviving systems that have evolved designs for maximizing power, ability to amplify and control may be in proportion to embodied energy. The evaluation of control effect and energy required in equivalent embodied energy units allows the direct correlation of these two properties of a controller such as a toxic chemical. The heavy metal cadmium (Cd) was used to analyze this toxin control hypothesis. A literature review indicated a stimulatory (Arndt-Schulz) effect of Cd at low concentrations in many growth studies. Most data sets were found to be described by a general subsidy-stress curve. The bioconcentration of Cd as a mechanism in natural systems for controlling free Cd concentration and its toxic effect is discussed. Information collected during previous research on Cd effect in experimental streams was summarized and used to calibrate an energy and material model of the Cd streams. Several mechanisms of Cd toxicity were examined and the model includes a simulation of system components at low Cd levels. The results of this study with Cd are predicted to be general to most other toxic substances and may allow synthesis of the burgeoning quantity of information concerning chemicals in the environment.