Vegan Health ArticlesFish and Shellfish: Contamination Problems Preclude Inclusion in the Dietary Guidelines for Americans
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From Spring 2004

Other Bioaccumulative Pollutants in Fish

There are four primary groups of pollutants in addition to the heavy metal mercury in waterways that accumulate in aquatic animals in concentrations many times higher than those in the water. Taken together, polychorinated biphenyls (PCBs), dioxin, chlordane, DDT, and mercury account for 96 percent of all fish advisories issued in 2002. Many other toxins, including other heavy metals and organochlorine pesticides, find their way into water and aquatic life as well.13

These pollutants are toxic to humans, fish, and other animals that consume and bioaccumulate them. Many of these chemicals are especially problematic, because they are not readily cleared from the body and accumulate over a lifetime. Thus, even if exposure is limited to a discreet period of time, the potential risks persist. According to the EPA, PCBs are known carcinogens in some species and a probable carcinogen in humans. PCBs also have been shown to disrupt immune function, cause learning disabilities, and disrupt neurological development; they may have endocrine effects as well. Furthermore, children born to women in fishing villages or exposed through occupational contact with PCBs have lower birth weight and lower weights for gestational age as PCB exposure level increases.14 Dioxins, too, are known carcinogens and have also been shown to cause liver damage, weight loss, and reductions in immune function, and to have a negative effect on early development and hormone levels.15 At high doses, human exposure to dioxins can result in a serious skin disease called chloracne.16 The main route of human exposure to dioxins is consumption of contaminated foods, especially fish and other products containing animal fats.17 Chlordane and DDT, an organochlorine, are pesticides that have been banned from use in the United States. Nonetheless, appreciable levels of these highly toxic chemicals remain in our waterways and bioaccumulate in fish.

Recent sources show that contamination with these pollutants is widespread both globally18 and domestically, especially in the Great Lakes region and the Eastern seaboard.13,19 In a survey of skipjack tuna from offshore waters around the world, Japanese researchers made an astonishing discovery. Organochlorines had contaminated every liver of every tested tuna, even though the fish came from a wide variety of locations, including Japan, Taiwan, the Philippines, Indonesia, Seychelles, and Brazil, as well as the Japan Sea, the East China Sea, the South China Sea, the Bay of Bengal, and the North Pacific Ocean. That researchers did not find even one uncontaminated liver illustrates how pervasive such pollution has become.18

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We began this archive as a means of assisting our visitors in answering many of their health and diet questions, and in encouraging them to take a pro-active part in their own health. We believe the articles and information contained herein are true, but are not presenting them as advice. We, personally, have found that a whole food vegan diet has helped our own health, and simply wish to share with others the things we have found. Each of us must make our own decisions, for it's our own body. If you have a health problem, see your own physician.