Lability of drinking water treatment residuals (WTR) immobilized phosphorus: aging and pH effects
In: Journal of environmental quality, Jg. 36 (2007-05-29), Heft 4
Online
unknown
Zugriff:
Time constraints associated with conducting long-term (>20 yr) field experiments to test the stability of drinking water treatment residuals (WTR) sorbed phosphorus (P) inhibit improved understanding of the fate of sorbed P in soils when important soil properties (e.g., pH) change. We used artificially aged samples to evaluate aging and pH effects on lability of WTR-immobilized P. Artificial aging was achieved through incubation at elevated temperatures (46 or 70 degrees C) for 4.5 yr, and through repeated wetting and drying for 2 yr. Using a modified isotopic ((32)P) dilution technique, coupled with a stepwise acidification procedure, we monitored changes in labile P concentrations over time. This technique enabled evaluation of the effect of pH on the lability of WTR-immobilized P. Within the pH range of 4 to 7, WTR amendment, coupled with artificial aging, ultimately reduced labile P concentrations by > or = 75% relative to the control (no-WTR) samples. Soil samples with different physicochemical properties from two 7.5-yr-old, one-time WTR-amended field sites were utilized to validate the trends observed with the artificially aged samples. Despite the differences in physicochemical properties among the three (two field-aged and one artificially aged) soil samples, similar trends of aging and pH effects on lability of WTR-immobilized P were observed. Labile P concentrations of the WTR-amended field-aged samples of the two sites decreased 6 mo after WTR amendment and the reduction persisted for 7.5 yr, ultimately resulting in > or = 70% reduction, compared to the control plots. We conclude that WTR application is capable of reducing labile P concentration in P-impacted soils, doing so for a long time, and that within the commonly encountered range of pH values for agricultural soils WTR-immobilized P should be stable.
Titel: |
Lability of drinking water treatment residuals (WTR) immobilized phosphorus: aging and pH effects
|
---|---|
Autor/in / Beteiligte Person: | Agyin-Birikorang, Sampson ; O'Connor, George A. |
Link: | |
Zeitschrift: | Journal of environmental quality, Jg. 36 (2007-05-29), Heft 4 |
Veröffentlichung: | 2007 |
Medientyp: | unknown |
ISSN: | 0047-2425 (print) |
Schlagwort: |
|
Sonstiges: |
|