Change in Trace Metal Fractions in Soils Long-Term After Cessation of the Three Different Organic Wastes Treatment for Seven Years.

This study was carried out to understand the long-term effect of organic waste treatment on the fate of trace metals in soil originated from the organic wastes. Three organic wastes(Municipal sewage sludge, alcohol fermentation processing sludge, pig manure compost) were used in three different rate for 7 years (1994-2000). To see the long-term effect, soil examination were conducted in 2000 and 2010, respectively. Speciation of trace metals in soil through sequential extraction showed that organically bound form of Cu was the dominant species in all treatment and exchangeable form of Cu was increased in the plots treated with municipal sewage sludge and alcohol fermentation processing sludge. Organically bound form of Ni increased from 25~30% to 32~45% in 2010 in all treatment while Pb showed increase in Carbonate extractable amount in all treatment. Zn existed mainly as Sulfide and residuals, showing increases in Organically bound form of Zn in all treatment after 10 years.