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A COMPREHENSIVE APPROACH TO IDENTIFY AND QUANTIFY FUNDAMENTAL PARAMETERS THAT INFLUENCE METAL LEACHING CHEMISTRY IN LANDFILLS SYSTEMS (ABSTRACT)
Citation:
AlAbed*, S R. A COMPREHENSIVE APPROACH TO IDENTIFY AND QUANTIFY FUNDAMENTAL PARAMETERS THAT INFLUENCE METAL LEACHING CHEMISTRY IN LANDFILLS SYSTEMS (ABSTRACT). Waste Testing & Quality Assurance Symposium (WTQA), Arlington, VA, 8/12-15/2002.
Description:
Various anthropogenic activities generate hazardous solid wastes that are affluent in heavy metals, which can cause significant damage to the environment and human health. Heavy metals/metalloids can exist in multiple oxidation states, and can undergo oxidation or reduction when they interact with mineral surfaces or organic compounds. Previous studies have demonstrated that, in natural environments, the mobility of these toxic metals is largely controlled by their interactions in their disposal environment. One of the major problems with solid wastes is the generation of large quantities of heavily contaminated leachate, which can cause extensive pollution of ground and surface aquatic bodies. The U.S. EPA Toxicity Characteristic Leaching Procedure (TCLP) is the most common tests used by regulatory agencies for classifying and comparing the leaching characteristics of different waste matrices. However, the test has several practical limitations and hence it is not applicable to the real landfill systems. The current TCLP method is inadequate to represent the real systems as it lacks to account for several important parameters that significantly affect the kinetics of the reactions occurring the solid-water interface including pH, reactant concentrations, reprecipitation reactions and secondary phases formations, physical characteristics of the solid wastes, residence time, and temperature. The need for reliable assessment and prediction of leaching behavior of waste materials has evoked a need to incorporate these factors in evaluating the leaching behavior of waste materials generated anthropogenically or naturally.
Our main research goal is to develop consistent predictive methods, for short- and long-term risk assessment of waste materials containing environmentally toxic metals, which would integrate the contributions of critical geochemical factors in addition to pH. Development and application of such predictive methods will aid in improving the current EPA approach of assessing metal leaching from anthropogenic and natural solid wastes.