What with the holidays and all, I rather lost track of Deep Sea News’ Gulf seafood safety series … to my detriment. It’s gotten very interesting.
As you may recall, the series started with a general overview of how seafood safety is determined. In part two – the nitty-gritty of seafood testing – Dr. Bik starts by questioning the reliability of “sensory testing” (AKA sniff and taste tests) and works her way up to a bit of a self-described rant:
1) [What] is with the low numbers of seafood being tested?!? Rule #1 in scientific studies is to have a large, statistically significant sample size. Sample sizes <30 for large swathes of the Gulf of Mexico is NOT empirically rigorous. I suspect that the limited testing is related to cost—chemical analysis isn’t cheap, with gas chromatography and mass spectrometry analysis running up to $750 per sample. However, usually a much cheaper approach is used to screen samples for potential contamination—methods like high performance liquid chromatography with fluorescence detection (HPLC/florescence), which NOAA has clearly been using on samples. Theroetically, BP should be covering the cost for all this screening anyway so in my opinion there really is no excuse.
2) Cookie cutter statistics–the way in which NOAA has determined their ‘Level of Concern’ (LOC) for human health risk is a bit dodgy. I know they need some sort of metric, but as the media has been reporting, Gulf coast residents eat a LOT of seafood. FDA tests clearly show PAHs in Gulf seafood, but they get a safe stamp because these levels fall below the national average LOC. However, a recent survey by the Natural Resources Defense Council estimates that Gulf residents eat much more than the national average (3-12 times as much seafood), with many respondents (60%) nothing that they weigh less than the FDA’s assumed weight and have risk-groups at home (e.g. children-40%) who also eat seafood. Also, FDA tests only test the actual flesh of shrimp, crabs, and oysters–many people in the gulf use the shells and organs in cooking, and anecdotal reports from consumers suggest that something just isn’t looking right. Even if you don’t live in the Gulf coast, you may eat a lot more seafood than the FDA assumes for its LOC (per month: nine 50z fish meals, four meals of four shrimp each, and about three 4.2 oz oyster meals). Who eats four shrimp per meal? For your further perusal, Dr. Gina Solomon offers an empassioned blog post on this topic.
As if Dr. Bik isn’t empassioned enough? But that’s neither here nor there. Her comments on sensory testing elicited a lengthy response from NOAA which, in turn, prompted her to air her real beef – it’s not so much the system itself, and the lack of transparency:
The message we keep getting from NOAA is “everything is safe, don’t worry, trust us”. What I would really like to see is “Everything is safe–here is the data in an easily accessible format so you can see for yourself”. Why can’t NOAA produce a simplified website with key information in obvious places–like a seafood consumption calculator, so you could compare the amount of Gulf seafood you eat (taking into account your age, gender, etc) with the recommended safe level for you as an individual. Instead of just posting written memos about seafood testing, how about a graphical description of type and amount (number of individuals, total weight of flesh) of each species tested. I love blogging and digesting this information for the public, but I do it because there is a need for it. I do it pro bono, in my free time between juggling classes, labwork, conferences, and meetings. It is, however, someone’s job at NOAA to communicate with the public.