MWH Laboratories implements new method for wastewater tracing

For Immediate Release: 1/6/2010

MWH Laboratories, a division of MWH Americas, Inc. has implemented a new method to help identify the presence of wastewater in ground and surface waters. Analyzing at ultra-low levels for gadolinium (Gd), a rare earth element typically used as a contrast agent in MRI scans¹, MWH can successfully identify a “gadolinium anomaly” in various ground and surface water samples, indicating the presence of wastewater. Being able to detect unusual levels of Gd at even parts per trillion (ppt) levels allows MWH to determine the presence of wastewater despite significant dilution.

Expanding upon work reported by the U.S. Geological Survey (2005) and more recent work done in Australia by the University of Queensland (2009), MWH utilized a state of the art Inductively Coupled Plasma Mass Spectrometer(Perkin Elmer 9000 ICPMS DRC2) equipped with special sample handling capabilities, to measure the entire suite of rare earth elements at levels as low as 1 ppt. By comparing the relative concentration of gadolinium (Gd) to the other rare earths, it is possible to determine whether there exists “excess” Gd, thereby indicating the apparent presence of wastewater.

The example below shows the power of this technique. Of five samples tested, two samples show the clear presence of significant excess of Gd (10-20 ppt), and one shows as light excess (2 ppt). Thus, this method can be used to determine wastewater presence despite extremely low concentrations.



Dr. Andrew Eaton, MWH Labs Technical Director, commented, “This technique gives us another arrow in our quiver to help clients determine whether their source water is exposed to wastewater. It supplements the methods we already developed for broad spectrum pharmaceutical and personal care product screens. We hope this will expand the knowledge of the importance of water quality.”

The technique implemented by MWH will be used shortly for a major study of reclaimed water in Florida.

¹Gadolinium (Gd) is injected into patients undergoing MRIs to improve the imaging quality and subsequently completely excreted by the patients within a few hours after injection.

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About MWH Laboratories

MWH is a private, employee-owned consulting firm with over 6,000 employees worldwide. The firm provides engineering design and remediation, construction, procurement, program management, and technology solutions for the environmental, land, water, wastewater, energy and power markets of the Americas, Europe, Middle East, India, Asia and the Pacific Rim.