Is the Cleanup working? SPMDs Help You Find Out.

By Sean Sheldrake and Alan Humphrey

EPA scientific diver.

EPA scientific diver Brent Richmond at work.

Some of you may have followed our previous blog posts about EPA’s scientific diving program in It’s Our Environment, but we also wanted to share some of our experiences with a new kind of environmental monitoring technique here on the It All Starts with Science blog.

In the “old days” of underwater cleanup, scientific divers would use biological sampling methods, dropping a cage or bag containing live specimens of fish or mussels into the deep blue to answer that age old question, “Is there something out there that needs cleaning up?”  But these studies are expensive to implement, and issues can arise before deployment – Oh no!

  • The aeration pumps died and so did the fish! 
  • High temperatures forecast today—our fish can’t take it! 
  • Argh, the aquarium says they won’t have enough juvenile salmonids available to complete our study! And so on…
Close up of SPME

EPA divers use SPMDs, small, solid-state environmental monitoring devices.

Today, we use Solid Phase Microextraction Devices—or SPMDs.  

These new methods give us less expensive and more reliable ways to document whether there are exposure concentrations on or in the seafloor that are at or above acceptable benchmarks. These techniques have emerged as a valuable tool to find out if the cleanup is “getting the job done” of protecting human health and the environment.

How can contaminants be measured?

SPMDs can detect low level contaminants with a special absorptive matrix and are easier to deploy than live specimens.  Using proper correlations to live counterparts, project managers can use such technique to see if a cleanup is needed. If a cleanup is already underway, such as the one at the Pacific Sound Resources (PSR) Site in Puget Sound, SPMD methods can be used to determine if the cleanup is working. 

Partnering with U.S. Army Corps of Engineers and the University of Texas, EPA’s Environmental Response Team and EPA Region 10 divers have placed and retrieved these devices at many Superfund sites, including: PSR, Duwamish, Portland Harbor, Wyckoff, and others.

SPMD are a valuable tool in determining if cleanup is needed, and for monitoring whether containment activities are getting the job done over time.

Read more about the latest in EPA scientific diving at

About the authors:  Sean Sheldrake and Alan Humphrey both serve on the EPA diving safety board, responsible for setting EPA diving policy requirements.  In addition, they both work to share contaminated water diving expertise with first responders and others.

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