seafood safety

RECENT POSTS

March 23, 2011 | 11:48 AM | By

Japan’s nuclear crisis not a threat to seafood

We’re getting a better idea of how much radioactive material has entered the ocean around Japan’s crippled Fukushima Dai-ichi nuclear power plant. Bloomberg reports that damaged fuel rods have released five different kinds of radioactive material and contaminated nearby seawater:

Iodine-131 was detected at 127 times normal levels from sample water taken at 2.30pm yesterday, while caesium-134 levels were 25 times normal and caesium-137 was at 17 times normal, Tepco said on its website.

Ken Buesseler of Woods Hole Oceanographic Institution told Bloomberg that radioactivity levlels

“This time of year off the coast of Japan, they would mix with water down 100 feet to 300 feet, and be diluted by a factor of about 100. The currents there would move it to the south, just north of Tokyo, and then out to sea.”

The ocean’s vast capacity to dilute out the radioactive material means that the nuclear crisis is unlikely to impact ocean life or create a seafood safety issue. As Ken told me last week, the Black Sea remained safe for swimming and eating seafood despite Cesium-137 levels 10-20 times normal after Chernobyl. Localized contamination of seaweed with radioactive iodine could be a concern for Japanese consumers, but iodine decays rapidly and will be gone within a month.

Similarly, Bill Camplin, group manager of radiological and chemical risk at the Centre for Environment, Fisheries and Aquaculture Science in Lowestoft, England, told Bloomberg the radioactive material poses a much greater risk to land-based food supplies.

“But my advice would be not to eat seafood caught from within the evacuation and sheltering zone,” or about 30 kilometers offshore, Camplin said in an e-mail. “Effects on wildlife in the sea are unlikely to be severe.”

The U.S. Food and Drug Administration is attempting to reassure American consumers about the safety of imported seafood, saying it is monitoring the situation closely:

Based on current information, there is no risk to the U.S. food supply. FDA is closely monitoring the situation in Japan and is working with the Japanese government and other U.S. agencies to continue to ensure that imported food remains safe.

FILED UNDER: Human Impacts, Fukushima nuclear crisis, seafood safety
March 18, 2011 | 4:57 PM | By

What does Japan’s nuclear crisis mean for ocean life?

Digital Globe

This satellite image from March 17, 2011, shows damage to nuclear reactors at the Fukushima Dai-ichi nuclear power plant in Japan caused by a magnitude 9.0 earthquake, the resulting tsunami, and subsequent explosions and fires caused by lack of cooling.

If there’s been a saving grace in Japan’s nuclear crisis to date, it’s been the weather. With the exception of recent precipitation pulling some radioactive material down to the ground near the Fukushima Daichi plant, offshore breezes have been pushing most of the radioactive material out to sea. That could be a lifesaver (literally) for the residents of northeastern Japan. But what does it mean for the billions of creatures who inhabit the Pacific Ocean?

To answer that question, I got in touch with Dr. Ken Buesseler, a scientist at Woods Hole Oceanographic Institution who has actually used radioactivity from Chernobyl and nuclear testing in his research tracking chemical processes in the ocean. I asked him if we have a handle on what the situation in the western Pacific is right now in terms of types and levels of radioactive material. Short answer: NO.

We have no data on fallout to the Pacific Ocean, other than they have said that releases include Iodine-131 and Cesium-137… Iodine-131 has a short half-life (8 days) and is gone in a month but is of more immediate exposure concern due to its uptake in the thyroid particularly by young children. Cesium-137 has a longer 30 year half life, so that will still be around after decades.

Where in the world – and ocean – radioactive material from Japan will end up depends largely on wind and weather conditions. As Jeff Masters explained recently on Wunderblog, the high pressure system that has been driving the offshore winds has also likely kept radioactive material close to the ocean’s surface, increasing the chances that much of the material will be deposited into the Pacific rather than whisked around the world on the air currents higher in the atmosphere.  Continue reading →

FILED UNDER: Ocean Change, Fukushima nuclear crisis, seafood safety
January 11, 2011 | 2:08 PM | By

Questioning Gulf seafood safety

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:

Image courtesy of NOAA

Preparing tissue samples for sensory and chemical analysis.

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. Continue reading →

FILED UNDER: Human Impacts, Gulf oil spill, seafood safety
December 20, 2010 | 2:31 PM | By

Gulf seafood: determining what’s safe

flickr/su-lin

Controversy continues to dog Gulf seafood in the wake of the Deepwater Horizon oil spill. Government officials say it's safe, but some experts argue otherwise.

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.

FILED UNDER: Human Impacts, Gulf oil spill, seafood safety
December 14, 2010 | 11:19 AM | By

The seafood safety equation: contamination, consumption, and size

According to NOAA and the Food and Drug Administration, Gulf seafood contains negligible traces of oil and dispersants from the Deepwater Horizon blowout.

But the seafood safety equation has three factors; contamination is just one. A person’s size and consumption patterns also have to be taken into account.

NRDC’s Wendy Gordon says FDA standards don’t provide adequate protection for women, children, and those who eat lots of seafood.

FDA sets a standard for how much Polycyclic Aromatic Hydrocarbons (cancer-causing chemicals released from the oil) are allowed in Gulf seafood. Once again, they base the standard on a national survey of fish consumption and do not take into account frequent seafood consumers, in particular those along the Gulf Coast. Nor do they consider more vulnerable subgroups whose size or developmental stage are not average.

So NRDC decides to do its own survey. You can see where this is going, I’m sure, and it’s not pretty. The results of NRDC’s survey confirm what local Gulf Coast residents were dreading — FDA’s seafood consumption numbers are way too low. Forty-three percent of the 550 Gulf Coast residents from Louisiana to Florida who were surveyed said they eat fish more frequently than the FDA estimates. The numbers were especially striking for shrimp: consumption rates were 3.6 to 12.1 times higher than FDA estimates. Vietnamese-Americans, reported significantly higher seafood consumption rates than other survey respondents, more than double in some cases. In addition, 60 percent of those surveyed reported that they weigh less than the 176-pound FDA estimated average. When coupled with increased consumption rates, lower body weight can result in a significantly increased dose of contaminants. Who are the smallest among us — pregnant women and children, who also happen to be the most vulnerable.

FILED UNDER: Human Impacts, seafood safety
August 17, 2010 | 9:20 PM | By

Is Gulf seafood safe to eat? For how long?

Fried shrimp

Courtesy of flickr user Old Shoe Woman

This is a must-read post from Mother Jones’s Blue Marble blog about the safety of eating Gulf seafood. The upshot? Seafood from the Gulf may be safe now, but it could become toxic in years to come as animals eat little bits of the remaining oil faster than they can clear it from their bodies. That’s according to a study published this week in the Journal of the American Medical Association.

FILED UNDER: Human Impacts, Ocean Change, Gulf oil spill, seafood safety