Testing Method Detects Gadolinium to Find Sewage

MWH Laboratories, a division of MWH, has introduced a new method to identify the presence of wastewater in ground and surface waters.

The advancement comes as municipalities address new evidence of contamination in U.S. water supplies, including bacteria often found in sewage. The method detects gadolinium (Gd) and other rare earth elements that are a proven and reliable indicator of sewage contamination, offering a new tool for water purification and treatment plants and others to identify the presence of wastewater in recycled water.

“This is a groundbreaking development for treatment plants charged with delivering clean water to the public as well as companies relying on clean water sources,” said Andrew Eaton, Ph.D., technical director for MWH Laboratories. “Plants can add an extra level of certainty to their work, using the same samples that they are already testing and with minimal added expense.”

MWH Laboratories now can analyze at ultra-low levels for gadolinium, a rare earth element typically injected into patients undergoing MRI scans to improve the imaging quality of the medical test. Once it passes through the body, gadolinium enters sewer systems. In samples of reclaimed water, a high level of gadolinium relative to other earth elements is one indicator of wastewater contamination.

The company can identify a “gadolinium anomaly” or excess levels of Gd at parts per trillion (ppt) levels to determine the presence of wastewater despite extremely low concentrations or significant dilution.

The new method has been used by the U.S. Geological Survey and researchers at the University of Queensland and will be used by MWH Labs for a major study of reclaimed water in Florida set to begin this spring, sponsored by the Florida Department of Environmental Protection. MWH Laboratories uses 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 and then uses a special algorithm to normalize the data and identify the presence of the Gd anomaly.