The good folks over at Deep Sea News are launching a new series of posts about the safety (or not) of Gulf seafood in the wake of the Deepwater Horizon oil spill. Part I is dedicated to how seafood contamination is measured.
The primary criteria for assessing seafood safety are polycyclic aromatic hydrocarbons … Low-molecular weight PAHs (naphthalene, fluorene, dibenzothiophene, anthracene and their substituted homologues) are pretty nasty compounds; highly soluble in water, highly toxic, and break down slowly—detecting these compounds in the water are typically used to assess potential seafood contamination. Interestingly, the NOAA publication “Managing Seafood Safety after an Oil Spill” notes that:
“There are no established limits for PAH exposure to assure food safety, but from prior experience with other oil spills, guidelines have been calculated for consideration. These guidelines account for both the amount and duration of exposure, and they vary by type of seafood. The guidelines are based on highly sensitive analytical detection of contaminants at concentration levels as low as parts per billion (ppb; one part contaminant per one billion parts of edible seafood).”
Gauging the overall safety of “seafood” is a complex undertaking because not all “seafood” is affected equally. Contamination levels can vary from species to species, depending on what they eat (filter-feeders and high-level predators typically take in the most), how quickly they eliminate the pollutants (fish tend to do a better job then shrimp), the season (fat-laden fish about to lay eggs hold more oily contaminants). And then there’s the human end of the equation – how much and what type of seafood you’re eating and, importantly, your age and size.
The more you know about your food, the better you can assess the risk. FDA tests currently state that the level of PAHs detected in their tests do not pose a human health risk–we’ll explore what those tests actually mean in the next part. Right now, what’s worth more–eating that delectable shrimp gumbo and reveling in your sated appetite, or foregoing Gulf seafood and gaining the peace of mind that you may be minutely decreasing your long-term cancer risk? There is no right or wrong answer—just different choices.