’s investigation finds nearly half of San Diego area swordfish and tuna contain hazardous levels of mercury

By November 16, 2011Got Mercury?
Nearly Half of San Diego Area Swordfish and Tuna Tested
Contained Hazardous Levels of Mercury

San Diego, CA- Nearly half of San Diego area supermarket swordfish and tuna samples tested contained hazardous levels of mercury according to an investigation led by the public health advocacy project

Eighteen samples of tuna and swordfish were purchased by two concerned residents of the San Diego area from 12 different grocery stores and analyzed for mercury content by an independent laboratory.

Forty four percent of the samples were found to contain levels of mercury exceeding the U.S. Food and Drug Administration’s (FDA) mercury action level of 1 part per million.  One piece of swordfish was almost 300 percent over the limit.  For the detailed report and mercury results please click here.

“Based on the findings eating tuna and swordfish could be harmful to your health,” said Buffy Martin Tarbox, Campaign Coordinator for, based in Forest Knolls, CA. “ is so concerned about the hazardous levels of mercury found in swordfish and tuna that we have issued a warning to the public to not eat these fish.”

“Prior to this study, I had no idea how contaminated swordfish and tuna can be,” said Barbara Lawson-Risso, one of the San Diego area residents who volunteered her time to collect the samples.  “People need to be made aware that a dangerous toxin is being sold at the seafood counter.”

All the samples contained mercury, a troubling finding since eating fish is the number one source of mercury exposure in the United States according to the Environmental Protection Agency (EPA).   In its own studies, the EPA has detected mercury in every fish sample within the continental U.S. The EPA has set a mercury action level at 0.5 ppm for recreational fish, half the level of the FDA standard for commercial fish.

This testing was conducted as part of national effort initiated by called Operation Safe Seafood to randomly test mercury levels in fish. Similar investigations conducted in Florida, New York, Iowa and the San Francisco Bay Area found on average, 35 percent of fish being sold in grocery stores exceeded the FDA’s mercury action level.

Consistently high mercury levels have prompted to issue a warning to fish eaters asking them to sign a pledge to protect themselves against mercury and abstain from eating tuna, swordfish, shark, gulf tilefish and king mackerel, all high-mercury fish.  The pledge is available in English, Spanish, Japanese, Vietnamese and Cantonese.

About works to protect people and the environment from mercury.  Because of the ubiquitous nature of mercury in the environment and because federal and state public health agencies are not doing enough to raise public awareness and protect the public from mercury, developed the free online mercury-in-fish calculators at and that have received millions of hits since 2002.


The FDA has issued a warning to women of childbearing age and young children to not eat swordfish and to limit consumption of tuna due to high mercury levels.

Mercury contamination of seafood is a widespread public health problem, especially for women of childbearing age, pregnant and nursing women and children.  Mercury ingestion can lead to memory loss, developmental and learning disorders, vision loss, heart disease and, in extreme cases, can result in death.

Currently there are no federal legal requirements to warn people about mercury in fish. has been seeking action from the California State Legislature, Congress and the FDA to mandate mercury in fish warning signs at grocery stores and restaurants but government has been slow to act.