Ecological Sciences and Engineering Interdisciplinary Graduate Program, Department of Agronomy, Purdue University, West Lafayette, IN 47907, USA.
Chemosphere. 2011 Feb;82(6):847-52. doi: 10.1016/j.chemosphere.2010.11.021. Epub 2010 Dec 3.
The application of manure and biosolids onto agricultural land has increased the risk of estrogenic exposure to aquatic systems. Both αE2 and βE2 have been routinely detected in surface and ground waters with higher concentrations reported near concentrated animal feeding operations and agricultural fields. Although movement through the soil to a water body is highly dependent on hormone-soil interactions, to date, only the interaction of βE2 with soils has been characterized despite αE2 often being the more common form excreted by livestock such as beef cattle and dairy. In predicting the transport of estradiol, sorption characteristics for the stereoisomers have been assumed to be the same. To evaluate this assumption, sorption of αE2 and βE2 was measured on seven surface soils representing a range in soil properties. Soils were autoclave-sterilized to minimize loss due to biotransformation, and both solution and soil phase concentrations were measured. Overall, E2 sorption is best correlated to soil organic carbon (OC) with an average log OC-normalized distribution coefficient (logKoc, L kgoc(-1)) of 2.97±0.13 for αE2 and 3.14±0.16 for βE2 with βE2 consistently exhibiting higher sorption than αE2 with the highest β/α sorption ratio of 1.9. Assuming that the two isomers sorb the same is not a conservative decision making approach. The lower sorption affinity of αE2 increases the likelihood that it will be leached from agricultural fields.
有机肥和生物固体在农业土地上的应用增加了雌激素暴露于水生系统的风险。αE2 和 βE2 都已在地表水和地下水中常规检测到，在集中式动物饲养场和农田附近报告的浓度较高。尽管通过土壤向水体的迁移高度依赖于激素-土壤相互作用，但迄今为止，尽管 αE2 通常是牛和奶牛等牲畜排泄的更常见形式，但仅对 βE2 与土壤的相互作用进行了表征。在预测雌二醇的迁移时，假定立体异构体的吸附特性是相同的。为了评估这一假设，在代表一系列土壤特性的七种表层土壤上测量了 αE2 和 βE2 的吸附。通过高压灭菌对土壤进行消毒，以最大程度地减少由于生物转化而导致的损失，并且测量了溶液相和土壤相浓度。总体而言，E2 吸附与土壤有机碳（OC）的相关性最好，αE2 的平均 OC 归一化分配系数（logKoc，L kgoc(-1))为 2.97±0.13，βE2 为 3.14±0.16，βE2 的吸附始终高于 αE2，β/α 吸附比最高为 1.9。假设两种异构体具有相同的吸附性并不是一种保守的决策方法。αE2 的吸附亲和力较低，增加了其从农田中淋滤的可能性。
