Fate of Di-2-(ethylhexyl)phthalate in Three Sludge-amended New Mexico Soils1
- B. C. Fairbanks,
- G. A. O'Connor and
- S. E. Smith2
Di-3-(ethylhexyl)phthalate (DEHP) is toxic organic of concern limiting the reuse of sewage sludge on agricultural lands. The degradation, volatilization, and adsorption of DEHP-14C were monitored in three calcareous soils from New Mexico amended or unamended with sewage sludge. Evolution of 14CO2 was the only mechanism of loss of DEPH from these soils. No volatilization of parent compound or organic metabolites was detected. The effects of sewage sludge on DEHP degradation varied with soil, DEHP concentration, and sludge incubation time. As a result, 50% disappearance time varied from 8 to 72 d, depending on treatment interactions. After 146 d, 76 to 93% of the DEHP-14C was evolved as CO2. In general, DEHP persistence was reduced by previous exposure of the soil to sludge, but was increased or unaffected by fresh additions of sludge. Increasing DEHP concentration from 2 to 20 mg kg−1 soil increased DEHP persistence. Degradation of DEHP was greater in two sandy loams (Typic Haplargids and Petrocalcic Paleustolls) than in a clay soil (Typic Torrifluvents). Preliminary data suggest extensive adsorption of DEHP by all soils with no effect of sewage sludge additions.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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