Advanced Water Management Centre (AWMC), The University of Queensland, St Lucia, Queensland, 4072, Australia.
Water Sci Technol. 2010;61(3):685-92. doi: 10.2166/wst.2010.885.
Stable gadolinium (Gd) complexes have been used as paramagnetic contrast agents for magnetic resonance imaging (MRI) for over 20 years, and have recently been identified as environmental contaminants. As the rare earth elements (REE), which include Gd, are able to be measured accurately at very low concentrations (e.g. Tb is measured at 7 fmol/kg in this study) using inductively coupled plasma mass spectrometry (ICP-MS), it is possible to determine the fate of this class of compounds during the production of purified recycled water from effluent. Coagulation and microfiltration have negligible removal, with the major removal step occurring across the reverse osmosis membrane where anthropogenic Gd (the amount of Gd attributable to MRI contrast agents) is reduced from 0.39 nmol/kg to 0.59 pmol/kg, a reduction of 99.85%. The RO concentrate has anthropogenic Gd concentrations of 2.6 nmol/kg, an increase in concentration in line with the design characteristics of the plant. The increased concentration in the RO concentrate may allow further development of anthropogenic Gd as a tracer of the fate of the RO concentrate in the environment.
稳定的钆（Gd）配合物已被用作磁共振成像（MRI）的顺磁对比剂超过 20 年，最近已被确定为环境污染物。由于包括 Gd 在内的稀土元素（REE）能够使用电感耦合等离子体质谱法（ICP-MS）在非常低的浓度下（例如，本研究中 Tb 的测量浓度为 7 fmol/kg）进行准确测量，因此可以确定在从废水生产纯化再循环水的过程中此类化合物的命运。混凝和微滤的去除率可忽略不计，主要的去除步骤发生在反渗透膜上，反渗透膜将人为 Gd（归因于 MRI 造影剂的 Gd 量）从 0.39 nmol/kg 降低至 0.59 pmol/kg，减少了 99.85%。RO 浓缩物中的人为 Gd 浓度为 2.6 nmol/kg，与工厂的设计特性一致，浓度增加。RO 浓缩物中浓度的增加可能允许进一步开发人为 Gd 作为 RO 浓缩物在环境中命运的示踪剂。
