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Gulf oil spill: fish safety test unveiled

October 29, 2010 |  3:53 pm

While government investigators, BP and Halliburton argue over the integrity of the well cement used last April in the run up to the explosion of the Deepwater Horizon oil rig, the lingering effects of the massive spill it caused continue to demand regulators' attention.

On Friday afternoon, the Food and Drug Administration and National Oceanic and Atmospheric Administration announced a chemical test to detect some residues of oil dispersant in fish and shellfish.

Previously, according to the two agencies, every seafood sample from waters reopened to fishing in the Gulf of Mexico has passed "a rigorous sensory analysis" -- mainly a sniff test.

But to bolster confidence in gulf seafood in the face of lingering concern over the impact of dispersant on the marine food chain, the FDA and NOAA said they're testing for dioctyl sodium sulfosuccinate, or DOSS, a major component of the chemical cocktails dumped in the gulf to break up the oil.

So far, scientists have tested 1,735 tissue samples and only 13 showed trace amounts of DOSS, all below safety threshholds for fin fish and shellfish, the agencies said.

The blowout of BP's Macondo well beneath the Deepwater Horizon drilling rig on April 20 killed 11 workers and caused the worst oil spill in U.S. history. 

Neither regulators' tests nor the results offer much comfort to Susan Shaw, a marine toxicologist and director of the Marine Environmental Research Institute in Blue Hill, Maine.

"It's an improvement for the agencies to have a tissue test for dispersant," Shaw said, but "it's been six months. How could possibly take this long to develop this test?"   

Moreover, DOSS is only one of hundreds of compounds formed by the mixture of seawater, oil and the two flavors of Correxit dispersant used on the spill, according to Shaw.

Perhaps most troubling to Shaw is the inability of independent scientists to verify the efficacy of the methods used by NOAA and the FDA. 

For example, Shaw said, it's not known in what parts of the gulf or where in the water column fish were collected for sampling. "We don't have transparency in the data. We don't have their sampling plan," Shaw said. 

About 9,444 square miles, or 4%, of federal waters in the gulf still are closed to commercial and recreational fishing.

Read more here about the new Gulf seafood test.

UPDATE: A NOAA spokeswoman emailed late Friday to assert that "there is full transparency to the data at issue" and pointed out a link to "Dispersant Test Results".

The link does contain data on where in the Gulf fish were sampled, though not other detail sought by Shaw.

-- Andrew Zajac