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EFFECTS OF BIOSOLIDS ON SORPTION AND DESORPTION BEHAVIOR OF CADMIUM IN BIOSOLIDS-AMENDED SOILS
Citation:
Ryan*, J A., G. M. Hettiarachchi**, AND K G. Scheckel*. EFFECTS OF BIOSOLIDS ON SORPTION AND DESORPTION BEHAVIOR OF CADMIUM IN BIOSOLIDS-AMENDED SOILS. Presented at Annual Meeting of the Soil Science Society of America, Denver, CO, 11/2-7/2003.
Description:
Cadmium sorption and desorption experiments were conducted on different fractions of soils amended with different biosolids with varying chemical properties and unamended soil (control). Biosolids addition increased the slope of the Cd sorption isotherms compared to the control soil. Slope increments were different for different biosolids. The slope increments exhibited a positive relationship to Fe and/or Mn in biosolids and a negative relationship to concentrations of other metals in biosolids. Removal of both OC and Fe/Mn removed the observed differences in the slopes of Cd sorption isotherms between the biosolids-amended soils and the control. Cadmium desorption showed that greater proportion of Cd sorbed by soils cannot be desorbed back to the solution and this "hysteresis" effect was higher for biosolids amended soils than the control soil. Results from this study show that behavior of Cd added to biosolids amended soils depends on biosolids chemical properties and supports the hypothesis that the addition of Fe and Mn in the biosolids increased the retention of Cd in biosolids-amended soils.