Marine Chemist Says “Not So Fast” to Quick Oil Detection Method


May 28, 2008

A new method for assessing environmental contamination after
oil spills is in danger of being applied in situations where it doesn’t work
and might produce false conclusions, a scientist at Woods Hole Oceanographic
Institution (WHOI) has warned.

Private firms and government agencies have recently started
using long strands of absorbent polypropylene snares, also called “pom-poms,” as
a means to check for contamination of the seafloor in the wake of an oil spill.
The method is becoming popular because it is rapid and low-cost.

But according to WHOI marine chemist Christopher Reddy, the approach
may give a false sense of security. In a recently published letter to the Marine
Pollution Bulletin
, Reddy notes that while the pom-pom method is effective
in locating areas where excessive amounts of oil have sunk to the bottom, it
does not necessarily identify the fractions and compounds of oil that can linger
in sediments and have long-term impacts on ecosystems and public health.

Following a 2004 oil spill in the Delaware
River, emergency response crews employed the new pom-pom method to
quickly determine the locations of large oil patches on the river floor. The
information was invaluable for the emergency response and cleanup.

After the M/V Cosco
oil spill in San
Francisco Bay
in November 2007, the pom-pom method was used again. But this time, the goal
was to determine if sediments near the Port of Oakland
were safe to be dredged and re-used in restoration projects.

“This approach is flawed,” Reddy wrote. “It relies on the
assumption that the lack of visible oil on the snares…indicates a total lack of
oil contamination in the sediment…While testing of sediments with snares
delivers rapid, low-cost data, it is only an indicator of gross contamination.”

“Before this approach becomes standard practice for
determining whether sediments have been contaminated at levels that may impact
ecosystems,” Reddy added, “prudence dictates much more rigorous testing of the
test itself.”

Funding for this
research was provided by the Richard and Rhoda Goldman Fund and the WHOI
Coastal Ocean Institute.

Related Links
» Marine Pollution Bulletin: A cautionary tale about
evaluating analytical methods to assess contamination after oil spills

» Oceanus: Popular Way to Assess Oil Spills Can Be Misused
» Comparing the San
Francisco Oil Spill to East Coast Analogs

» Oceanus: Still Toxic After All These Years