Anthropogenic gadolinium (Gd_anth) is a frequent contaminant in surface water that receives wastewater treatment (WWT) effluents due to the high stability of Gd-based contrast agents (Gd-CAs) used in magnetic resonance imaging (MRI) exams and excreted by patients. This study describes the presence of Gd_anth in surface water of a small drainage area (circa 4 km²), which does not receive WWT effluents. The unexpected Gd_anth anomalies were attributed to raw sewage leaking from underground effluent removal pipes. The study area is within a university campus with a hospital that regularly runs MRI exams employing Gd-CAs. Besides Gd, the whole lanthanide (Ln) series was measured and except for Gd, all remaining Ln data were correlated, implicating that besides the natural Gd, a distinct Gd species contributes up to 95% to its whole content in the water samples. Besides surface water, samples of the local sewage and pluvial water networks were collected and analyzed. The ratio between measured and expected Gd values (Gd/Gd*) in surface water samples ranged between 1 and 46, the first corresponding to pristine locations and absence of Gd anomaly and the second nearby the sewage and pluvial water networks. The Gd_anth anomalies presented transient values, probably associated with the application of the Gd-CAs to patients and their permanence in the hospital. Other proxies commonly associated to sewage discharge also presented transient values, not necessarily correlated Gd_anth, because of the input of distinct anthropogenic sources in the study area.

人为钆 (Gd _anth ) 是接受废水处理 (WWT) 流出物的地表水中的常见污染物，因为磁共振成像 (MRI) 检查中使用的基于 Gd 的造影剂 (Gd-CA) 具有高稳定性并由患者排泄. 本研究描述了在不接受 WWT 废水的小流域（约 4 公里²）的地表水中存在 Gd_花粉。意想不到的Gd _anth异常是由于未处理的污水从地下污水排放管道泄漏。研究区域位于大学校园内，医院定期使用 Gd-CA 进行 MRI 检查。除了 Gd，测量了整个镧系元素 (Ln) 系列，除了 Gd，所有剩余的 Ln 数据都是相关的，这意味着除了天然 Gd 之外，不同的 Gd 物种在水样中占其总含量的 95%。除地表水外，还收集和分析了当地污水和雨水网络的样本。地表水样品中测量的和预期的 Gd 值 (Gd/Gd*) 之间的比率介于 1 和 46 之间，第一个对应于原始位置和 Gd 异常的缺失，第二个对应于污水和雨水网络附近。Gd_花粉异常呈现瞬时值，可能与 Gd-CA 对患者的应用及其在医院中的持久性有关。通常与污水排放相关的其他代理也呈现瞬态值，不一定与 Gd _anth相关，因为在研究区域输入了不同的人为来源。