Evaluating the behavior of gadolinium and other rare earth elements through large metropolitan sewage treatment plants

Environmental Science & Technology
By: , and 

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Abstract

A primary pathway for emerging contaminants (pharmaceuticals, personal care products, steroids, and hormones) to enter aquatic ecosystems is effluent from sewage treatment plants (STP), and identifying technologies to minimize the amount of these contaminants released is important. Quantifying the flux of these contaminants through STPs is difficult. This study evaluates the behavior of gadolinium, a rare earth element (REE) utilized as a contrasting agent in magnetic resonance imaging (MRI), through four full-scale metropolitan STPs that utilize several biosolids thickening, conditioning, stabilization, and dewatering processing technologies. The organically complexed Gd from MRIs has been shown to be stable in aquatic systems and has the potential to be utilized as a conservative tracer in STP operations to compare to an emerging contaminant of interest. Influent and effluent waters display large enrichments in Gd compared to other REEs. In contrast, most sludge samples from the STPs do not display Gd enrichments, including primary sludges and end-product sludges. The excess Gd appears to remain in the liquid phase throughout the STP operations, but detailed quantification of the input Gd load and residence times of various STP operations is needed to utilize Gd as a conservative tracer.

Publication type Article
Publication Subtype Journal Article
Title Evaluating the behavior of gadolinium and other rare earth elements through large metropolitan sewage treatment plants
Series title Environmental Science & Technology
DOI 10.1021/es903888t
Volume 44
Issue 10
Year Published 2010
Language English
Publisher American Chemical Society
Contributing office(s) National Water Quality Laboratory, Toxic Substances Hydrology Program
Description 7 p.
First page 3876
Last page 3882
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