Degradation Kinetics and Metabolites of Carbamazepine in Soil
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- 作者：Juying Li ; Laurel Dodgen ; Qingfu Ye ; Jay Gan
- 刊名：Environmental Science & Technology (ES&T)
- 出版年：2013
- 出版时间：April 16, 2013
- 年：2013
- 卷：47
- 期：8
- 页码：3678-3684
- 全文大小：332K
- 年卷期：v.47,no.8(April 16, 2013)
- ISSN：1520-5851
文摘
The antiepileptic drug carbamazepine (CBZ) is one of the most frequently detected human pharmaceuticals in wastewater effluents and biosolids. Soil is a primary environmental compartment receiving CBZ through wastewater irrigation and biosolid application. In this study, we explored the transformation of CBZ to biologically active intermediates in soil. Both 14C labeling and liquid chromatography鈥搕andem mass spectrometry (LC鈥揗S/MS) were used to track transformation kinetics and identify major degradation intermediates. Through 120 days of incubation under aerobic conditions, mineralization of CBZ did not exceed 2% of the spiked rate in different soils. Amendment of biosolids further suppressed mineralization. The fraction of non-extractable (i.e., bound) residue also remained negligible (<5%). On the other hand, CBZ was transformed to a range of degradation intermediates, including 10,11-dihydro-10-hydroxycarbamazepine, carbamazepine-10,11-epoxide, acridone-N-carbaldehyde, 4-aldehyde-9-acridone, and acridine, of which acridone-N-carbaldehyde was formed in a large fraction and appeared to be recalcitrant to further degradation. Electrocyclization, ring cleavage, hydrogen shift, carbonylation, and decarbonylation contributed to CBZ transformative reactions in soil, producing biologically active products. The persistence of the parent compound and formation of incomplete intermediates suggest that CBZ has a high risk for off-site transport from soil, such as accumulation into plants and contamination of groundwater.