Citation:

Hettiarachchi**, G. M., K G. Scheckel*, J A. Ryan*, S. R. Sutton, AND M. Newville. METAL-BINDING ROLE OF IRON AND MANGANESE OXIDES IN BIOSOLIDS-AMENDED SOILS . IN: Advanced Photon Source Activity Report 2002, Argonne National Laboratory, Argonne, ILANL-03/21, (2003).

Description:

The environmental impact and potential hazards of metals in biosolids to plants, animals and the human food chain have been studied for decades. From this body of work, it has been concluded that the addition of biosolids to the soil alters the soil system beyond that of the simple addition of greater quantities of trace elements. Further, it is apparent that this alteration does not require large additions of biosolids. The phase or phases responsible for this alteration continues to be in dispute. Some researchers postulated and supported the "time-bomb" hypothesis in which it is assumed that the responsible phase is organic and as the organic material decomposes its complexing nature will be lost with a subsequent release of metal to the inorganic system where it will behave as a salt addition to the soil. In contrast, some predicted that biosolids adsorption chemistry related to inorganic surfaces. Based on these understandings, researchers began to characterize the chemical aspects of biosolids that made metals so much less available to plants (phytoavailable) or biological systems (bioavailable) than were metal-salts. Studies from long-term field application sites illustrated that bioavailability does not increase as the added organic matter decreases.

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