CHEMICAL WITHIN US
BY REPUBLISHED FROM THE PAGES OF NATIONAL GEOGRAPHIC MAGAZINE
January 16th, 2019
For people in northern California, mercury exposure is also a legacy of the gold rush 150 years ago, when miners used quicksilver, or liquid mercury, to separate the gold from other ores in the hodgepodge of mines in the Sierra Nevada. Over the decades, streams and groundwater washed mercury-laden sediment out of the old mine tailings and swept it into San Francisco Bay.
I don't eat much fish, and the levels of mercury in my blood were modest. But I wondered what would happen if I gorged on large fish for a meal or two. So one afternoon I bought some halibut and swordfish at a fish market in the old Ferry Building on San Francisco Bay. Both were caught in the ocean just outside the Golden Gate, where they might have picked up mercury from the old mines. That night I ate the halibut with basil and a dash of soy sauce; I downed the swordfish for breakfast with eggs (cooked in my nonstick pan).
Twenty-four hours later I had my blood drawn and retested. My level of mercury had more than doubled, from 5 micrograms per liter to a higher-than-recommended 12. Mercury at 70 or 80 micrograms per liter is dangerous for adults, says Leo Trasande, and much lower levels can affect children. "Children have suffered losses in IQ at 5.8 micrograms." He advises me to avoid repeating the gorge experiment.
Hi Zahra.Wow! I had no idea that consumption of fish for two meals would impact the level of mercury in the body so significantly. My entire family has an affinity for fish, I do not. so, when I look for fish we will only buy wild caught but I am not sure if that is even sufficient at this point. Fish is supposed to be healthy, right?
ReplyDeleteGreat post.
Cinnamon
Hi Zahra,
ReplyDeleteI have studied about the Gold Rush numerous times in my history classes, but I never knew about the mercury exposure and how it created an impact on the SF Bay. My mom eats plenty of fish in her diet since she started living in San Francisco at least 30 years ago. Her primary care provider actually tested my mom’s mercury levels and it was abnormally high. We just have to be more mindful about the food that we consume and the source of our food. I was vegan for over a year and recently slowly incorporated fish in my diet. However, I am limiting the amount I consume to prevent obtaining high levels of mercury in my blood. I have not tested my mercury levels yet but it would be interesting to know.