Coupled reversion and stream-hyporheic exchange processes increase environmental persistence of trenbolone metabolites
Coupled reversion and stream-hyporheic exchange processes increase environmental persistence of trenbolone metabolites
复制标题
耦合的回复和流-潜流交换过程增加了群勃龙代谢物的环境持久性
DOI：
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发表时间：
2015
影响因子：
16.6
通讯作者：
Colleen C. Brehm
中科院分区：
文献类型：
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作者：
A. Ward;David M. Cwiertny;Edward P. Kolodziej;Colleen C. Brehm
美国现有的水污染物监管框架是理想化的，往往缺乏解释污染物的机制，其特征是：(1)母体和转化产物的生物活性；(2)由化学或物理异质性驱动的可逆转化(即亚稳态产物)。在这里，我们模拟了新发现的醋酸曲诺酮(TBA)代谢物的产物到母体的逆转途径。我们发现，暴露于初级代谢物17α-trenbolone(17α-tbOH)的剂量增加，仍具有生物活性的初级光产物羟化17α-tbOH的浓度升高，这种产物通过光转化产生，然后在与地表水光学区持续交换的永久黑暗的浅层带中转化回17α-trenbolone。持久性的增加等同于在逆转是主要的特伦勃隆命运途径的地点和时间来自母体-产品联合生物活性的更大潜在危险。我们的研究突出了当前风险表征范式中的不确定性和脆弱性。在农业径流中发现的牛生长激素代谢物主要通过光降解从地表水中去除。在这里，沃德等人。开发一个河流运输模型，在永久黑暗的低渗漏区发现回归会增加这些内分泌干扰物在环境中的持久性。
Existing regulatory frameworks for aquatic pollutants in the United States are idealized, often lacking mechanisms to account for contaminants characterized by (1) bioactivity of both the parent and transformation products and (2) reversible transformations (that is, metastable products) driven by chemical or physical heterogeneities. Here, we modelled a newly discovered product-to-parent reversion pathway for trenbolone acetate (TBA) metabolites. We show increased exposure to the primary metabolite, 17α-trenbolone (17α-TBOH), and elevated concentrations of the still-bioactive primary photoproduct hydroxylated 17α-TBOH, produced via phototransformation and then converted back to 17α-trenbolone in perpetually dark hyporheic zones that exchange continuously with surface water photic zones. The increased persistence equates to a greater potential hazard from parent-product joint bioactivity at locations and times when reversion is a dominant trenbolone fate pathway. Our study highlights uncertainties and vulnerabilities with current paradigms in risk characterization. Cattle growth hormone metabolites found in agricultural runoff are primarily removed from surface waters by photodegradation. Here, Ward et al. develop a model of stream transport, finding reversion in perpetually dark hyporheic zones increases environmental persistence of these endocrine disruptors.