Mercury is a poisonous metallic element that is liquid at room temperature.

There's nothing like producing a controversial story on some favorite food group to have a profound effect on one's appetite. I gave up chicken after doing a story on factory farms (I already didn't eat beef or pork or I would have eliminated those as well.) Now, fish, too, has fallen from grace. Ignorance was bliss.

I've known for quite some time that some fish, especially tuna, were high in mercury. But discovering the extent of the problem, and that halibut and sea bass were also on the “do not eat too much of” list, was eye-opening for me. Now I count fish servings like some people count calories. Japanese cuisine, one of my favorites, has lost some of its glow, as well as its frequency in my dining-out plans.

Many of you have practical questions, as did I. How big a crimp does this have to put in my diet? How much is too much? How often is too often? Can I still enjoy that tuna sashimi and not worry about mercury overload?

Because there wasn't time in the QUEST TV segment on mercury in the bay to include information on safe fish eating practices, below are the guidelines, along with web links, to help you get plenty of Omega 3s and still keep your mercury levels low.

Here's what California's Office of Environmental Health Hazard Assessment says about eating fish from the San Francisco Bay and Delta Region.

• Women beyond childbearing age and men should eat no more than two meals per month of San Francisco Bay sport fish, including sturgeon and striped bass caught in the delta. (One meal for an adult is about eight ounces).
• Women beyond childbearing age and men should not eat any striped bass over 35 inches.
• Women of childbearing age, pregnant, nursing mothers, and children should not eat more than one meal of Bay fish per month. In addition, they should not eat any striped bass over 27 inches or any shark.
• This advisory does not apply to salmon, anchovies, herring, and smelt caught in the bay; other sport fish caught in the delta or ocean; or commercial fish.
• Richmond Harbor Channel area: In addition to the above advice, no one should eat any croakers, surfperches, bullheads, gobies or shellfish taken within the Richmond Harbor Channel area because of high levels of chemicals detected there.

Here’s a summary of the joint fish advisory published by the FDA and EPA for women who are pregnant, breastfeeding or may become pregnant and for children. This is a general advisory not exclusive to any water body.

• Do not eat Shark, Swordfish, King Mackerel, or Tilefish because they contain high levels of mercury.
• Eat up to 12 ounces (2 average meals) a week of a variety of fish and shellfish that are lower in mercury. Five of the most commonly eaten fish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish.
• Another commonly eaten fish, albacore ("white") tuna has more mercury than canned light tuna. So, when choosing your two meals of fish and shellfish, eat only up to 6 ounces (one average meal) of albacore tuna per week.
• Check local advisories about the safety of fish caught by family and friends in your local lakes, rivers, and coastal areas. If no advice is available, eat up to 6 ounces (one average meal) per week of fish you catch from local waters, but don't consume any other fish during that week.
• Follow these same recommendations when feeding fish and shellfish to your young child, but serve smaller portions.

Also, check for local advisories for each water body in California that has fish consumption guidelines. They vary by water body.

And lastly, here’s some practical advice from Dr. Jane Hightower, the medical doctor who we feature in the mercury story.

• “If you’re genetically susceptible, it’s really important to know that if you are an autoimmune-prone patient, Lupus, MS, thyroiditis, these kinds of things, then you should not consume mercury on a regular basis or at all. … And then the cardiac patients. You know, mercury can cause a reaction in vessels that leads to inflammation. So you want to have your Omega 3 fatty acids, which is anti-inflammatory. And not have mercury which is pro-inflammatory…. If you want to avoid significant mercury and you just don’t know what the mercury content is in the fish, a rule of thumb is to eat the small fish. Not a piece of the fish. If it comes in a steak, you want to know how big the fish was that the steak came from. You want the whole fish to fit on your plate. Don’t buy a bigger plate. Get a smaller fish. With the exception of salmon. Salmon can have elevated mercury, but very rarely.”

Good luck, good health, and and watch out for bones!




Watch the Mercury in San Francisco Bay television story online.

View Larger Map

In honor of Earth Day, we wanted to take a big look at a chronic environmental issue in the Bay Area, tracing it from its origins to the contemporary strategies to solve it. Mercury was the obvious choice: It's been flowing into the Bay since before California joined the union, and it continues to trickle in from not just the old culprits, like gold and mercury mines, but a modern crop of industries, like refineries and cement kilns. Even little things – like a broken mercury thermometer dumped into the sink – are part of the problem.

The key fact here is how incredibly potent mercury can be: Just one little globule from an old thermometer can poison all the fish in a 45-acre lake, making them unsafe for humans to eat. Mercury pollution is hardly unique to the Bay Area; what makes us interesting is that local officials are making real strides in trying to clean it up. Over the next 17 years or so, we'll spend $2.6 billion dollars on the project. Even then, we won’t have a clean bay for 120 years.

For a lot of people, mercury pollution in the Bay is largely theoretical, since few stores sell fish caught in the Bay, and relatively few residents fish for their food. But some still do – including many recent immigrants from fishing-intensive cultures like Laos. We’ll look at how mercury affects the health of local fishermen next week.

This piece marks our first-ever audio slide show, and what a difference it makes! We also hope you'll check out the mercury map above, where you can see how many pounds of mercury come from each of the Bay Area’s five refineries, plus other mercury sources and the bay's popular fishing spots.

Watch the audio slide show of "Mercury in the Bay" online, as well as find additional links and resources.

Amy Standen is a Reporter for QUEST and Radio News at KQED-FM.