Detection of anthropogenic gadolinium in treated wastewater in South East Queensland, Australia

The use of refractory gadolinium (Gd) complexes as paramagnetic contrast agents in magnetic resonance imaging has resulted in point source release of anthropogenic Gd (GdAnthGdAnth) into the environment, and presents opportunities to trace the fate of wastewater in natural environments. We demonstrate an inductively coupled plasma mass spectrometry (ICP-MS) technique that is capable of detecting GdAnthGdAnth at concentrations as low as 48 fM, approximately six orders of magnitude lower than most other micropollutants, without the need for preconcentration. Further, we establish the ubiquitous presence of GdAnthGdAnth in wastewater at eight separate wastewater treatment plants in Brisbane, Australia, over a 3-month time period. In contrast, there is no evidence of GdAnthGdAnth in tap water, or in four separate regional water supply dams in South East Queensland, Australia. It is, therefore, highly unlikely that other anthropogenic micropollutants sourced from urban wastewater would be present in the drinking water supply.