Pesticides are an extremely important issue. Worldwide, there are more than 900 different active pesticides in some 40 000 different chemical formulations.^iv In the U.S., about 600 pesticide ingredients are used, accounting for some 800 million to 1 billion pounds per year.^v

Huff and Haseman reviewed some 200 rodent studies. They concluded that “there is considerable evidence that exposure to certain pesticides may present real carcinogenic hazards to humans.”^vi

How do fish become exposed to pesticides? One major cause is agricultural runoff. When a farmer sprays his fields, a portion of the chemicals run off into neighboring creeks, streams, rivers, and oceans. Overflows of sewage, faulty septic systems, boating waters, and poisonous runoff from city streets have also contributed to the pollution of waters. These waters are sometimes considered so dangerous that signs like “Swimming Prohibited” are erected on some beaches.

If swimming in the water is hazardous for humans, it is ironic that people still go fishing in these areas. The signs are not “crying wolf.” Illness such as gastroenteritis, dysentery, hepatitis, and more have resulted from swimming in contaminated water.

The risk of spending time in bodies of water on our globe is highlighted by a disturbing trend among fish. Fish are found with more cancer now than 50 years ago.^vii A Canadian biologist, Ron Sonstegard, has examined bottom-dwelling fish in the Great Lakes and the rivers that feed them. He has found tumors in every fish species—often malignant.^viii For example, 30 percent of the bullheads in Lake Erie had liver cancer.

The Ph. D. nutritionist and author, Dr. Winston Craig, in commenting on these findings added three more sobering facts: (1) the Great Lakes situation is not unique—cancerous fish turn up from Puget Sound to the Gulf of California and from the Hudson River to the Florida Keys; (2) National Cancer Institute data show an increased death rate from cancer among people living in areas where fish have exceptionally large amounts of tumours; (3) the toxic nature of what is found in some of our waterways is astonishing. When sediments from the bottom of Lake Erie were painted on the skin of mice, the mice developed skin cancers.^ix

Although Craig’s insight may not necessarily prove human risk, they surely raise serious concerns about the human health hazards related to the “epidemic” of cancers in fish.

Here are some possible links to cancer from contaminated fish:

• Elevated levels of pesticide compounds have been found in the tissue of breast-cancer patients.


• National Cancer Institute data show an increased death rate from cancer among people living in areas where fish have exceptionally large amounts of tumours.


• Fish have more cancer now than 50 years ago. Example: 30 percent of the bullheads in Lake Erie were found with liver cancer.

Rather large amounts of fish die in droves every year throughout our country due to pollution. The Environmental Protection Agency (E.P.A.) of the U.S. government has attempted to trace the amount of fish kills due to pollution as well as other causes. Figure 1 reports by state the number of fish kills caused by pollution in 1993.^x

Each fish kill in the figure can represent literally thousands of fish. The E.P.A. admits that these statistics greatly underestimate the actual number of fish kills, since 15 states did not report to keep track of their fish kills. Also, many fish kills occur that cannot be definitely proven to be due to pollution.^xi

Pesticides were the most frequently identified toxic pollutant causes fish kills, followed by oil and gasoline products, chlorine, ammonia, heavy metals, and other toxic substances. Unfortunately, many ill fish that are suffering from these pollutants are caught by fisherman, taken to market, and consumed by humans who think they are eating healthy food.

Dr. Craig has pointed out another serious concern with fish safety. There is no government mandatory inspection program for fish or fish products at this writing. Craig states that only 10 percent of fish undergo any type of inspection, and this is through a voluntary program.^xii Obviously, there is need for a well-ordered fish inspection system.

If we could find non-fish sources of the beneficial omega-3 fats, wouldn’t it be more sensible from all that we have learned, to set fish aside? Such foods would not provide a potential reservoir for cancer, infectious diseases, and other ailments.

With cancer being the greatest concern regarding exposure to pesticides and other toxins, we must recognize which toxins pose the greatest long-term exposure risk. Poisons that present the greatest long-term threats to humans have two natural characteristics—a tendency toward both bioaccumulation and biomagnifications. Both of these process cause fish from mildly polluted waters to have large concentrations of toxins in their tissues.

Bioaccumulation is the process of which toxins gradually build up in certain organs of humans or other target organisms. Biomagnifications refers to a process where toxins become progressively more concentrated as they move up in the food chain.^xiii

A classic example of biomagnifications was discovered in Clear Lake, California, about 90 miles north of San Francisco.^xiv The lake had been sprayed several times with an insecticide called DDD to control the insect population. (DDD, a less potent cousin of the infamous DDT, is technically referred to as a halogenated hydrocarbon.)

The lake water revealed barely detectable levels of this pesticide, at .02 parts per million (2 drops of DDD in every 100 million drops of lake water). Biomagnifications, however, caused a dramatic increase in the tissue levels of organisms that lived in the lake. The concentration of DDD in the phytoplankton in the lake measured 5 ppm, which is 250 times the conception in the lake water. In progressing up the food chain, the concentration of DDD approached 2 500 ppm—a whopping 125,000 times the concentration in the water.

One of the most common questions I receive after giving a public health presentation involves the quality of household water. Many people are very concerned about what toxins might be in their tap water. They should be much more concerned about the quality of water in the rivers, lakes, streams, and oceans where the fish that they are eating come from. Low levels of toxins, such as in Clear Lake, California, result in high levels of toxins in the fish that humans consume every day.

Such examples of biomagnifications are not the exception: they are the rule. The EPA has gone on record saying “Aquatic organisms may bioaccumulate environmental contaminants to more than 1 million times the concentrations detected in the water...” ^xv

Evidence is mounting that there may be a relationship between toxins and chronic human diseases such as cancer and heart disease that affect the developed nations in epidemic proportions. One piece of evidence involves the halogenated hydrocarbons, which is one class of compounds known to be biomagnified through the food chain.

Halogenated hydrocarbons also bioaccumulate in humans. Elevated levels of these compounds have been found in the tissue of breast cancer patients.^xvi The researchers who identified this breast cancer linkage concluded, “These results, although preliminary, suggest a role for environmentally derived suspect carcinogens in the genesis [origin] of mammary [breast] carcinoma.”

But the problems do not stop with cancer. One investigator, in his review of the literature, found a “correlation between DDT and DDE [two other halogenated hydrocarbons] in the blood and subjects who reported hypertensions, arteriosclerosis, and diabetes during subsequent years...”^xvii

Fish present some of the greatest concerns from the standpoint of biomagnifications and bioaccumulation. They are not only contaminated with PCB’s and various heavy metals such as mercury, but also with petroleum hydrocarbons and halogenated organic compounds.^xviii,xix In a prominent medical textbook on environmental medical issues, Dr Kenneth Rosenman of Michigan State University stated, “The major ongoing source of PCB exposure for the general population is the consumption of fish.”^xx Along with concerns about causing cancer, there is preliminary evidence linking both PCBs and dioxins with elevated blood cholesterol and triglycerides.^xxi Other data indicated that PCBs may affect male sperm counts and fertility.^xxii

Research suggests that these contaminants can harm the developing fetus has increased the stakes in the PCB issue even further. Dr. Theo Colborn has pointed out that the research literature suggests that PCB present in the womb can “affect the developing nervous system of the embryo, fetus, and newborn.”^xxiii Recently, the New England Journal of Medicine grabbed headlines when Drs. Joseph and Sandra Jacobsen further determined the developmental risks of PCB exposure.^xxiv At 11 years of age, children with higher exposures to PCBs before birth showed impaired intellectual development. Although the children were not retarded, those with the highest PCB exposures were three times more likely to have low IQs and twice as likely to be at least two years behind in their reading comprehension.

Accumulation of toxic metals in fish has recently caused particular concern in light of the problem of acid rain. Acid rain leads to acidified waters. This chemically altered water can then leach aluminum, manganese, lead, zinc, cadmium, and mercury out of bottom sediments of soil and into the water. Once these toxic metals are liberated, they find their way into the food chain and tend to bioaccumulate in fish tissues.

Even in scenic Maine, women of childbearing age and children under eight are being urged not to eat fish from any pond or lake in Maine. Others are advised to restrict their annual consumption to no more than six large fish or 22 small ones, all due to the mercury content of the fish.^xxv Mercury ingestion in high levels can harm the development of human fetuses and children, and cause nervous system disorders and kidney damage in children and adults.

Michigan is the only other state to issue such a state-wide warning. However, according to Martha Keating, an EPA staff scientist, other U.S. lakes and streams are just as hazardous as Maine’s. The Boston-based Clean Water Action group has even gone on record stating that 90 percent of fresh water fish caught in New England waters, have contamination levels of mercury, lead, PCBs, or dioxin that are unsafe when consumed more than once a week. Although the group had collected significantly less data on saltwater fish, (so could not make a similarly sweeping statement), they did warn that the saltwater fish that were tested had high levels of PCB and mercury.

Probably the most widely publicized case of fish-related heavy metal poisoning had nothing to do with acid rain. It involved the tragic methyl mercury poisoning that result from eating fish from Japan’s Minamata Bay. Japanese factory discharges of methyl mercury into the bay laid the biomagnifications that occurred through the food chain exposed humans who ate the fish to dangerous organic mercury levels.^xxvi

Some nutritionists would say that in certain individuals, risks of consuming fish are outweighed by the benefits of a diet high in omega-3 fats, particularly the mental and heart benefits. A diet high in omega-3 may also help rheumatoid arthritis and ulcerative colitis.^xxvii

Happily, there is a way to have the benefits of the omega-3 fatty acids without the risk of eating fish, fish oil, or expensive supplements. There is a way to bypass the cholesterol and toxins that come with the animal-derived omega-3. The way is so simple, yet it is not getting the publicity it deserves. We can obtain the benefits of omega-3 fatty acids from a plant fat called “Linolenic acid.” A certain variety of plant foods are high in omega-3 and can supply all the body’s needs for this essential fat. A list of plant foods high in omega-3 is provided in Figure 2.

It is possible for both meat-eaters and vegetarians to have a diet too low in omega-3 fats. For individuals who have depression or bipolar disorder, I recommend that each day they consume dishes that include some foods high in omega-3. I recommend that at least one meal a day include foods high in omega-3. I also recommend a minimum supplementation of 9 grams of omega-3 fats per day—ideally from plant sources.

Some nutritionists believe that it is not only important for the diet to contain sufficient omega-3 but to also emphasize foods that have a higher omega-3 to omega-6 fatty acid ratio. The average American consumes a diet many times higher in omega-6 than omega-3. Appendix VIII lists foods with a more favorable omega-3 to omega-6 ratio.