Geosyntec and SiREM Practitioners Publish on Using Passive Samplers to Measure Metals in Water and Sediment

The article was published online on October 27, 2026, in Science of the Total Environment. It was also published on November 10, 2026, in Volume 1055 of the journal.

Authors include Geosyntec's Florent Risacher and Jason Conder, PhD, IBERAD, and SiREM's Brent Pautler, PhD.

Florent is a Project Scientist based in Canada with more than 10 years of experience focusing on surface water chemistry, limnology, and the role of microbes in water geochemistry. He uses his field experience to lead various mining projects, including the microbial characterization of biological passive treatment systems.

Jason is a Senior Principal Scientist based in California with more than 20 years of experience focused on risk assessment and contaminated sediments in contaminated site assessment and management, environmental toxicology, and ecological and human health risk assessment.

Brent is the Chemistry Services Manager at SiREM in Ontario. He brings more than 10 years of experience in spectroscopy, chromatography, mass spectrometry, passive sampling, and chemistry informatics. Throughout his career, he has worked with scientists, engineers, and consultants to help solve unique problems in the laboratory and the field.

The Science of the Total Environment is an international scientific journal that publishes research on environmental science, particularly studies examining interactions among the atmosphere, water, soil, ecosystems, and human activities.

Abstract: "Using Performance Reference Compounds to Assess Diffusion Kinetics of Peeper Passive Samplers to Measure the Availability of Inorganics"

Dialysis passive samplers (peepers) are often used to measure inorganics in sediment porewater and water. Reverse tracers, added to peepers before their deployment, can be used to estimate the degree to which the peeper has equilibrated with the aqueous matrix via the use of diffusion modeling to predict equilibrium concentrations of non-equilibrated target analytes. Despite the availability of the tracer approach and potential benefits to peeper applications, reverse tracers are not frequently applied due to a lack of clear methods and few practical demonstrations of the approach. This paper evaluated and demonstrated the application of a lithium bromide reverse tracer in peepers via measuring the kinetics of metals analytes and lithium in peepers in water under laboratory conditions. Laboratory results with metal-spiked water indicated that Li tracer data could be used to predict equilibrium concentrations of target metals in water to within 20% accuracy if the deployment time when the tracer achieved at least 50% to 75% equilibrium.

A field demonstration of peepers deployed in surface sediment and surface water for 10 days indicated 90% measured equilibration for the tracer and predicted equilibration of 70% to 90% for target metals. This data indicated deployment periods as short as 4 to 7 days could provide a reasonable estimate of equilibrium concentrations of the metal target analytes using the diffusion modeling approach. Longer peeper deployment periods are likely to result in tracer equilibration above 90% such that the modeling is unnecessary. For more compact and/or finer-grained sediments with lower diffusivity, it is recommended to deploy peepers for approximately 14 to 21 days or longer. Regardless of the deployment time or peeper design, it is recommended to measure a tracer so that the relative level of peeper equilibration can be measured in sediment or surface-water field deployments.

More Information on Passive Samplers and Deployment Times in Water and Sediment

Read the article.
Learn more about Science of the Total Environment.
For more information on passive sampling and passive treatment systems, contact Florent at [email protected].
Learn more about Florent: Florent Risacher
Learn more about Jason: Jason Conder
Learn more about Brent: Brent Pautler