Metallic elements exist in the earth's crust and natural environment. Human requires some trace metals (e.g., copper, iron, and selenium) to maintain normal body functions; on the other hand, if we intake of some certain metals may adversely affect our health. According to the World Health Organization (WHO), there are four metals causing significant public health concerns, i.e., arsenic, cadmium, lead and mercury. Metal contaminants can taint the food through environmental pollution (e.g. air, soil and water) or during food processing; so, they may be present in food with trace amount. Some news media have been reported that excessive cadmium was detected in rice due to grow on cadmium-contaminated soil. Thus, it has raised our public's attention to the hazardous food impacted on our health.

What is Cadmium (Cd)?

          Cadmium is a metal element. It is present on the earth's crust and ubiquitous in the natural environment. It can be released into the environment to cause various pollutions by industrial activities, such as production of batteries, pigments, plastics, electroplating, smelting, etc.

Sources of Cadmium Intake

          People are usually exposed to cadmium through dietary. Crops grown in contaminated soil or water, such as rice and vegetables, may contain cadmium. In addition, if seafood lives in the contaminated water, the cadmium may be accumulated into their bodies, particularly of shellfish.

Health Effects

        The International Agency for Research on Cancer (IARC) of World Health Organization has classified cadmium and cadmium compounds as carcinogenic agents to humans (Group 1). The Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (JECFA) has established the safety reference value (i.e. provisional tolerable monthly intake - PTMI) for cadmium of 25 micrograms per kilogram of body weight per month (μg/kg bw/month). In general, acute cadmium poisoning through our normal dietary is unlikely. However, long-term ingestion may result in chronic toxicity that negatively affects kidney function. It may lead to different symptoms, such as proteinuria, glycosuria and aminoaciduria, etc. High intake of cadmium may disturb the calcium metabolism and form kidney stones.

Advice to the Public

• Buy food from reputable shops with good hygiene condition;
• Soak vegetables in clean water and wash them thoroughly;
• Remove the viscera of shellfish before cooking, and only consume its adductor muscles;
• Maintain a balanced and varied diet to avoid excessive intake of contaminants from a small range of food items. 

002/DIR/DSA/2018