Retention of fly ash-derived copper in sediments of the Pandu River near Kanpur, India

• Published in: Environmental geology (Berlin) 1994-10, Vol.24 (2), p.133-139
• Main Authors: RAVI CHANDER, D. V, VENKOBACHAR, C, RAYMAHASHAY, B. C
• Format: Article
• Language: English
• Subjects: Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Freshwater; Marine and continental quaternary; Pollution, environment geology; Surficial geology
• ISSN: 0943-0105; 1432-0495
• DOI: 10.1007/BF00767886

A coal-based thermal power plant is situated on the bank of the Pandu River (a tributary to the Ganges River near Kanpur, Uttar Pradesh). River sediments downstream from the ash pond outfall are contaminated by fly ash. In order to establish the role of soils and sediments in retaining fly ash-derived heavy metals, copper was investigated as a model metal. A maximum concentration of 70 ppm Cu could be leached from the fly ash, confirming that it is a major source of this metal. Soil samples and river sediments were examined for Cu adsorption in the natural state as well as after treatment with H sub(2)O sub(2), EDTA, and H sub(2)O sub(2) followed by EDTA. The organic fraction of the samples was determined, and it had a major control on removal of Cu from a solution with 10 super(-4) M initial concentration. Further characterization of organic matter indicated that with reference to natural samples, the humic acid fraction had a copper enrichment factor in the range 9.1-15.1. The factor for fulvic acids, in contrast, was between 3.5 and 5.5. This leads to the conclusion that river deposits rich in humic acids would withstand relatively high metal loads. Only when the metal input exceeds the maximum retention potential, would the metal be fractionated into the aqueous phase and act as a potential biocide.