Summary

 

• Accidents in nuclear plants can lead to the release of radioactive materials into the natural environment, contaminating the air and water sources. They can make their way into the food chains and accumulate in the human body, which can induce cancer and pose hazards to human health;
• After the radioactive materials release radiation, as to whether consuming radioactively contaminated food affects human health, it depends on factors such as the type and quantity of radionuclide ingested, and the frequency of ingestion. Different radionuclides have different effects on the human body, and among them, radioactive iodine-131, cesium-134 and cesium-137 are the dominant radionuclides that affect human health;
• The Administrative Regulation No. 16/2014 “Maximum Limits of Radionuclides in Foodstuffs” of Macao establishes the maximum permissible limits of radioactive iodine-131, cesium-134 and cesium-137 in foodstuffs intended for infants and other foodstuffs to ensure the foodstuffs commercially available in Macao are safe for consumption;
• In response to the nuclear accident in Fukushima of Japan in 2011, the Macao government has promptly adopted control measures for foodstuffs imported from Japan to prevent the spread of risk. In accordance with Chief Executive Writ of Instruction No. 134/2023, the import of fresh and live food products, food products of animal origin, sea salt and seaweed, including vegetables, fruits, milk and milk products, aquatic products and their derivatives, meat and meat products, and poultry eggs originating from ten prefectures of Japan has been banned in Macao starting from 24 August, 2023. 

Introduction

 

In 2011, a disastrous nuclear accident happened at a nuclear power plant in Fukushima Prefecture of Japan, resulting in the leakage of large amounts of radionuclides. In 2023, the Japanese government has moved on with its plan of discharging treated radioactive wastewater containing tritium and other radionuclides into the Pacific Ocean, triggering global attention. So far, there is still uncertainty as to whether the radioactive materials in the wastewater discharged into the ocean over a long course of time will have adverse impacts on the marine ecosystems and global food safety, raising public concerns.

 

Radiation and radioactivity

 

Radiation refers to the energy that moves from one place to another in the form of waves or particles. It is further divided into natural radiation and man-made radiation by source. Natural radiation comes from varied natural radioactive materials in the environment, as found in soil, water, air, and in the human body. Man-made sources of radiation include radiological diagnostics, industrial applications, and nuclear power generation. Radiation is silent, colourless, odourless and tasteless, but can be detected and measured with the use of instruments.

 

A nuclear power plant is safe when it is functioning properly, but accidents in nuclear plants can lead to the release of radioactive materials into the natural environment. The released radioactive materials are scattered in the atmosphere, deposited in water and soil, which can pose hazards to the human body. Among them, radioactive iodine-131, cesium-134 and cesium-137 are the dominant radionuclides that affect human health. Each type of radionuclide has a specific half-life. For instance, iodine-131 has a half-life of 8 days, while cesium-134 and cesium-137 have a half-life of approximately 2 years and 30 years, respectively. Moreover, the length of time that a released radioactive material remains in the environment can be affected by factors such as the type and concentration of the radioactive material, as well weather conditions.

 

Radioactive contaminants in food products

 

Radionuclides exist in the nature, and food and water sources can be contaminated with trace amounts of radioactive materials. The radioactivity concentration and amounts of radiation released into the environment during a nuclear bomb explosion or an accident in a nuclear power plant are relatively high. The released radioactive materials are carried by the wind, along with water flow or by animals to farmlands, grasslands, rivers, lakes, oceans and other places, where they make their way into the food chains. When humans consume radioactively contaminated food for an extended period of time, the radioactive materials will accumulate and decay in the human body, which increases the risk of cancer and poses hazard to health.

 

After a nuclear accident, the released radioactive materials can contaminate food and water sources. They travel through the air or deposited in rainwater, so the surfaces of vegetables, fruits, or animal feed are susceptible to contamination by radioactive materials. After a period of time, these radioactive materials can migrate from the soil to crops, and enter the body of animals through contaminated animal feeds. Aquatic foods, like fish and shellfish, can be exposed to radioactive contaminants present in the water. The discharge of radioactive wastewater into the ocean could have serious impacts on marine ecosystems and human health. Organisms in the food chain might absorb radioactive materials and accumulate them in their body to the extent of endangering the safety of aquatic foods consumed by humans, such as fish, shellfish, seaweed and kelp, which could be more susceptible to radioactive contamination comparing to other types of food products.

 

Natural radiation is present in the environment, and the human body is able to repair damages caused by low levels of radiation exposure through metabolic processes. As to whether consuming radioactively contaminated food affects human health, it depends on factors such as the type and quantity of radionuclide ingested, and the frequency of ingestion. Different radionuclides have different effects on human health. Among them, upon consumption of food containing radioactive iodine and cesium, these radioactive materials can accumulate in the human body and are likely to induce cancer in humans, and children are at a higher risk of developing cancer than adults.

 

In general, the foodstuffs available in the market are unlikely to have been exposed to high levels of radiation, and consuming them is unlikely to cause acute health effects. However, prolonged consumption of food exposed to radiation could potentially increase the risk of cancer in humans.

 

Regulation and control in place in Macao and internationally

 

In response to contamination of food by nuclear radiation, different regions and countries will implement appropriate control measures based on risk assessment and local circumstances. The measures may include enhanced monitoring and testing, restrictions on import of food products, and prohibiting the sale of specific food products. Moreover, the Food and Agriculture Organization and the World Health Organization (FAO/WHO) of the United Nations, in conjunction with the Codex Alimentarius Commission, have set the “Guideline Levels for Radionuclides in Foods Following Accidental Nuclear Contamination for Use in International Trade”, which establishes the maximum limits for radionuclide levels in foodstuffs intended for infants and other foodstuffs for use in international food trade. In general, as long as the levels of radionuclides in food do not exceed the corresponding guideline levels, the food should be considered as safe for human consumption.

 

Food availability in Macao mainly depends on imports. For food imported into Macao and sold on the market, Administrative Regulation No. 16/2014 “Maximum Limits of Radionuclides in Foodstuffs” establishes the maximum permissible limits of radioactive iodine-131, cesium-134 and cesium-137 in foodstuffs intended for infants and other foodstuffs to ensure the foodstuffs commercially available in Macao are safe for consumption. If the level of any of the radionuclides in food exceeds the corresponding maximum permissible limit, the government may take immediate actions, as determined by the degree and extent of risk posed, such as removal from shelf, recall, and marking and sealing of the affected food product, in order to prevent the distribution of harmful food in the market and safeguard the health of the public.

 

Since the nuclear accident in Fukushima of Japan in 2011, the Macao government has adopted control measures for foodstuffs imported from Japan to prevent the spread of risk. A multi-tiered approach is in place to ensure food safety. Levels of radiation in imported foodstuffs and those commercially available in the market are constantly monitored during their inspections, including the levels of radioactive materials in foodstuffs imported from Japan, and the respective findings are timely updated and released for the information of the public. In response to the discharge of radioactive wastewater into the ocean by Japan, control measures are adopted at import level. In accordance with Chief Executive Writ of Instruction No. 134/2023, the import of fresh and live food products, food products of animal origin, sea salt and seaweed, including vegetables, fruits, milk and milk products, aquatic products and their derivatives, meat and meat products, and poultry eggs originating from the 10 prefectures and regions of Japan, namely Fukushima Prefecture, Chiba Prefecture, Tochigi Prefecture, Ibaraki Prefecture, Gunma Prefecture, Miyagi Prefecture, Niigata Prefecture, Nagano Prefecture, Saitama Prefecture and Tokyo Metropolis, has been banned in Macao starting from 24 August, 2023. At the market level, the Municipal Affairs Bureau has stepped up testing for radiation levels in foodstuffs imported from Japan and in Japanese foodstuffs commercially available in the local market. So far, all tested food samples complied with the food safety standards and no abnormalities have been detected.

 

Advice for food industry and the public

 

• The food industry should order food products from reputable suppliers, and have a clear understanding of their origin;
• For food importers, they are required to declare to the competent authorities of Macao the food products to be imported and subject them to mandatory inspection in accordance with the law. They also have to present the health certificate and required test certificate of the food products issued by competent authorities of their country of origin. Upon receipt of imported food products, they should check on the integrity of food packaging and read the information on the food labels;
• Always stay informed about latest import control measures and food testing data through reference to announcements of the SAR government of Macao to ensure food safety in the production and marketing of foodstuffs;
• Consumers can reduce the potential presence of radioactive materials on food surfaces through washing, and removal of their outer skin or leaves;
• Always read the label on food packaging carefully to know the origin of the food during shopping. If there is any doubt about the origin or quality of the food, do not buy nor consume it;
• There is no need for the public to hoard iodised salt. Currently, there is no scientific evidence supporting that the ingestion of iodised salt can prevent or reduce the effects of radiation on human health.

 

References:

1.      Chief Executive Writ of Instruction No. 134/2023 “Ban on Import of Certain Products from Japan to Macao Special Administrative Region”

https://bo.io.gov.mo/bo/i/2023/34/despce_cn.asp#134

 

2.      Administrative Regulation No. 16/2014 “Maximum Limits of Radionuclides in Foodstuffs”

https://bo.io.gov.mo/bo/i/2014/34/regadm16_cn.asp

 

BRR 009 DAR 2023