Abstract

Heavy metals chelated by organic ligands and sites may endanger adjacent water bodies. Potential chelation capacity of solutions was determined through the effect of the chelating agents on the solubility of CaCO₃. The method is simple and yields consistent results.

Leachates from sanitary landfill models were incubated aerobically and anaerobically with clay loam, calcareous clay loam, and CaCO₃ for periods of up to 120 days. No significant adsorption of the chelates was detected. Decomposition of chelates in the anaerobic systems was very slow and insignificant. Decomposition in aerobic systems was relatively fast, leading to a residual chelation capacity of only 0.1–1% of the initial value after a 74-day incubation. It is essential, accordingly, to avoid direct drainage of anaerobic leachates from a waste disposal site into a water body.

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