Something in the Water: A Consequence of Nuclear Radiation

Toxicologist warns of methylmercury poisoning from fish consumption

Experts recommend choosing fish with low methylmercury content and avoiding fish skin and organs. Gaus Alex/Shutterstock

The release of treated Fukushima nuclear wastewater into the sea starting Aug. 24 has once again raised concerns about seafood consumption. Dr. Yen Tzung-Hai, director of the Toxicology Laboratory at Chang Gung Memorial Hospital in Linkou, Taiwan, explained in the Epoch Times’ “Health 1+1” program that tritium in nuclear wastewater is not harmful to the human body. However, continuous monitoring is required to ensure radioactive elements such as strontium-90 and cesium-137, which have carcinogenic risks, are removed in the treatment process. He also cautioned the public to be careful when consuming deep-sea large fish, as methylmercury poisoning from these fish can affect the central nervous system, and there is no antidote.

Japanese authorities announced that after undergoing treatment with the Advanced Liquid Processing System (ALPS), the nuclear wastewater to be discharged into the sea has had all radioactive substances removed except for tritium, which is present at concentrations of less than 1,500 becquerels per liter. The International Atomic Energy Agency (IAEA) has also stated that it agrees with Japan’s plan to discharge the treated nuclear wastewater into the sea, emphasizing that the discharge plan complies with international standards. However, the public remains concerned about potentially harmful substances in the nuclear wastewater.

Tritium Poses Little Risk, Cesium and Strontium Increase Cancer Risk

Dr. Yen explained that, theoretically, if the treated nuclear wastewater contains only tritium at a concentration below 1,500 becquerels per liter, it should not pose any problems. Tritium is commonly found in the environment and does not penetrate the human body significantly.

Regarding concerns about whether other radioactive substances, such as strontium-90 and cesium-137, might remain in the water, Dr. Yen stated that the half-lives of strontium-90 and cesium-137 are 29 years and 30 years, respectively, and only 12 years have passed since the nuclear disaster. After the commencement of the discharge of nuclear wastewater into the sea, there is still a need to continuously monitor whether strontium-90, cesium-137, and other pollutants have exceeded the standard.

What are the consequences if radioactive strontium-90 and cesium-137 enter the human body? Dr. Yen pointed out that chemically similar to potassium, cesium tends to accumulate in a person’s muscles, soft tissues, and organs, increasing the risk of various cancers. Strontium, similar in structure to calcium, can easily accumulate in the bones, increasing the risk of bone cancer and leukemia.

Deep-Sea Large Fish Contain Methylmercury

In addition to nuclear radiation, Dr. Yen cautioned against heavy metal pollution, particularly methylmercury, when consuming seafood, especially deep-sea large fish such as tuna, shark, and swordfish. These long-lived fish have spent over a decade in the ocean, accumulating significant amounts of methylmercury.

Methylmercury can damage the central nervous system and harm pregnant women and infants. A study in the United States found that pregnant women who consumed seafood containing methylmercury experienced a decrease in their babies’ IQs by up to 1.5 points.

One of the most famous mercury poisoning incidents in history is the Minamata disease (pdf) in Japan, resulting from mercury contamination in industrial wastewater. People who consumed contaminated seafood suffered from methylmercury poisoning, which caused neurological abnormalities, including speech difficulties, unsteady gait, blindness, deafness, seizures, and even death. Babies born in the affected areas were also born with deformities.

Dr. Yen explained that mercury is classified into three medical categories: elemental, organic, and inorganic. Chelating agents (such as DMPS and DMSA) can be used orally or by injection to remove mercury from the body or through kidney dialysis for elemental mercury and inorganic mercury poisoning. However, methylmercury, being organic, currently has no antidote. Thus, it is crucial to avoid consuming excessive amounts of methylmercury.

5 Precautions for Fish Consumption

Some people may reduce their seafood consumption due to concerns about nuclear radiation and heavy metal pollution and opt for freshwater fish instead. However, Dr. Yen still recommends that patients eat marine fish because freshwater fish can also be contaminated with antibiotics. Marine fish contain nutrients such as omega-3 unsaturated fatty acids, which are beneficial for preventing cardiovascular diseases.

How do we obtain the nutritional benefits of fish while avoiding fish toxins? Dr. Yen advises taking the following precautions:

1. Eat more small fish, less large fish: Small fish, about the size of your hand, have shorter lifespans and lower mercury content.
2. Avoid eating fish heads, skin, and organs: Fish heads, skin, fat, and organs contain toxins, including mercury and other heavy metals, environmental hormones, and polychlorinated biphenyls (PCBs), making them unsuitable for consumption.
3. Limit deep-sea large fish consumption to 80 grams weekly: For adults weighing around 110 pounds (50 kilograms), consuming a maximum of 80 grams of deep-sea large fish per week, equivalent to half the size of your hand, or three to four slices of sashimi, is recommended.
4. Children and pregnant women should avoid deep-sea large fish: Methylmercury can impact the intellectual development of fetuses and infants, making it advisable for children under six and pregnant women to avoid consuming them. Dr. Yen cited the U.S. Food and Drug Administration’s (FDA) recommendations that pregnant and breastfeeding women and young children should avoid eating the following fish: king mackerel, marlin, orange roughy, shark, swordfish, tilefish (from the Gulf of Mexico), and bigeye tuna.
5. Drink plenty of water to aid in detoxification: Most heavy metals are water-soluble, and drinking plenty of plain water can facilitate the excretion of heavy metals through urine.