Kinetics of Di-(2-ethylhexyl)phthalate Mineralization in Sludge-Amended Soil

Autor:	Jesper Bandsholm Thyme, Peter Lindequist Madsen, Per Moldrup, Peter Roslev, Kaj Henriksen
Rok vydání:	1999
Předmět:	endocrine system Phthalate Soil chemistry General Chemistry Mineralization (soil science) Biodegradation complex mixtures Soil contamination chemistry.chemical_compound chemistry Environmental chemistry Soil water Environmental Chemistry Sludge Waste disposal
Zdroj:	Madsen, P L, Thyme, J B, Henriksen, K, MØldrup, P & Roslev, P 1999, ' Kinetics of di-(2-ethylhexyl)phthalate mineralization in sludge-amended soil ', Environmental Science and Technology, vol. 33, no. 15, pp. 2601-2606 . https://doi.org/10.1021/es981015o
ISSN:	1520-5851 0013-936X
DOI:	10.1021/es981015o
Popis:	Sewage sludge is frequently used as a soil fertilizer although it may contain elevated concentrations of priority pollutants including di-(2- ethylhexyl)phthalate (DEHP). In the present study, the kinetics of microbial [14C]DEHP mineralization was studied in laboratory microcosms with sewage sludge and agricultural soil. A biphasic model with two independent kinetic expressions was used to fit the mineralization data. The initial mineralization activity was described well by first-order kinetics (r2 > 0.97), whereas mineralization in long-term incubations (>40 days) was described better by fractional power kinetics (r2 > 0.95). The mineralization activity was much lower in the late phase presumably due to a decline in the bioavailability of DEHP caused by diffusion-limited desorption. The initial DEHP mineralization rate in sludge-amended soil varied between 3.7 and 20.3 ng of DEHP (g dw)-1 d-1 depending on incubation conditions. Aerobic DEHP mineralization was 4-5 times faster than anaerobic mineralization. DEHP mineralization in sludge-amended soil was much more temperature sensitive than was DEHP mineralization in soil without sludge. Indigenous microorganisms in the sewage sludge appeared to dominate DEHP degradation in sludge-amended soil. It was estimated that >41% of the DEHP in sludge-amended soil will have escaped mineralization after 1 year. In the absence of oxygen, >68% of the DEHP will not be mineralized within 1 year. Collectively, the data suggest that a significant fraction of the DEHP in sludge-amended soils may escape mineralization under in situ conditions.
Databáze:	OpenAIRE
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