Mass Balance Approaches to Characterizing the Leaching Potential of Trenbolone Acetate Metabolites in Agro-Ecosystems

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• 作者：Gerrad D. Jones ; Peter V. Benchetler ; Kenneth W. Tate ; Edward P. Kolodziej
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：April 1, 2014
• 年：2014
• 卷：48
• 期：7
• 页码：3715-3723
• 全文大小：374K
• 年卷期：v.48,no.7(April 1, 2014)
• ISSN：1520-5851

文摘

Several studies have documented the occurrence and fate of trenbolone acetate (TBA) metabolites in soil and water. However, considerable uncertainty still exists with respect to TBA risk in agro-ecosystems because limited data are available to quantify excretion, transformation, and leaching processes. To address these uncertainties, we used experimental mesocosms and a mass balance approach to estimate the TBA metabolite leaching potential from manure excreted by implanted (40 mg TBA, 8 mg 17尾-estradiol) beef cattle. Manure sample analysis indicates that over 113 days, a maximum of 9.3% (3,200 渭g/animal unit [AU]) of the implant dose was excreted as 17伪-trenbolone (17伪-TBOH), and <1% was excreted as 17尾-trenbolone (65 渭g/AU) or trendione (3 渭g/AU). While most (>97%) of the total excreted mass of 17伪-TBOH transforms to uncharacterized products, 0.3鈥?.6% (100鈥?20 渭g/AU) of the implant dose accumulates on land surfaces and is available for subsequent transport. During rainfall or irrigation events, a maximum of 0.005鈥?.06% (1.6鈥?2 渭g/AU 17伪-TBOH) or 0.005鈥?.012% (1.8鈥? 渭g/AU 17伪-TBOH) of the dose leached into runoff, respectively. Leaching potentials peak at 5鈥?0 days postimplantation, suggesting that targeted timing of implantation and irrigation could minimize steroid leaching during rainfall and irrigation events.