Toxic Marine Animals

You would never knowingly eat a meal laced with mercury, PCBs, DDT, lead, or industrial-strength fire retardants. But if you’re consuming tuna, salmon, or other aquatic animals, you’re ingesting all these toxins and more. The government has already issued warnings about the toxins found in fish flesh, and countless studies have shown that consuming contaminated fish can have serious health consequences.

Fish absorb all the contamination in our waterways, so fish flesh is laced with toxins such as mercury, PCBs, DDT, dioxins, lead, arsenic, and a range of other chemicals. Studies have shown that people who eat fish have elevated concentrations of dangerous chemicals in their blood, and researchers at the University of Illinois College of Veterinary Medicine found that fish-eaters with high levels of PCBs in their blood had difficulty recalling information that they had learned just 30 minutes earlier.⁶⁶ Researchers have also found that the contaminants in fish can lead to nervous system disorders, birth defects, mental impairment, and heart problems.^67,68

Mercury is one of the most dangerous toxins found in fish flesh. Fish consumption is the sole source of human exposure to this known poison, and eating even small amounts of fish flesh can have a big impact on the levels of methyl mercury in our blood.⁶⁹ A study by the Environmental Protection Agency (EPA) revealed that women who ate fish just twice a week had blood mercury concentrations seven times higher than women who hadn’t eaten fish in the previous month.⁷⁰ Studies have also shown that a 140-pound woman will be 30 percent over the EPA cutoff for safe mercury levels if she eats just one 6-ounce can of white tuna each week.⁷¹

Mercury is known to cause severe health problems in humans, including brain damage, memory loss, personality change, tremors, spontaneous abortion, and damage to a developing fetus.⁷² The EPA estimates that up to 600,000 children born in 2000 are at risk for lower intelligence and learning difficulties because of mercury exposure because their pregnant or nursing mothers ate fish.⁷³

A study conducted by San Francisco physician Jane Hightower found that dozens of her patients had high levels of mercury in their bodies, and many showed symptoms of mercury poisoning, including hair loss, fatigue, depression, difficulty concentrating, and headaches. She found that her patients’ symptoms improved when they stopped eating fish.⁷⁴ “[Mercury is] a documented poison. Wherever it’s seen, it’s been a problem,” says Hightower.⁷⁵ Read more about mercury and other toxins in fish flesh.

Learn more about other contaminants.