Mercury poisoning: Basic facts you should know

Mercury is a silvery metal in liquid form. It is found in many products such as medical devices, light bulbs, batteries, and dental fillings.

When these mercury-containing products and devices are used properly, there is little danger to the person and the environment. However, when breakage and spills occur, such as broken light bulbs and leaking medical devices, then there is imminent danger. These accidents may pose a hazard to the hospital, dental service or chemical factories.

In this article, I will share with you several tips to keep you safe from mercury poisoning.

Health effects

Adults with mercury poisoning may develop muscle weakness, tremors, impaired speech, difficulty walking, headaches, insomnia, irritability, and skin rashes. Children may have learning difficulties and problems with fine movement and eyesight.

For persons with severe exposure to mercury, the effects can escalate to kidney disease, respiratory failure, and even death. Moreover, pregnant women should be extra careful because the unborn fetus is especially susceptible to the effects of mercury.

Sources of Mercury

You get mercury from the following:

• Fish. Mercury occurs naturally in the earth’s crust and can be found in coal. When man burns coal, mercury is released into the air. Later on, the mercury in the air will settle on land where it will seep into the water. In the water, mercury can be taken up by certain fish and shellfish and this can, in turn, be eaten by man. In a normal diet, very little mercury gets into our body. However, certain fish have higher amounts of mercury. Generally, the larger the fish (more than one foot), the greater the mercury content.

• Compact fluorescent light bulbs (CFLs). A fluorescent light bulb uses electricity to excite mercury vapor, which then produces visible light. Compared to traditional incandescent bulbs, the CFLs have several advantages and one disadvantage. CFLs are more efficient, use less energy and help reduce greenhouse gas emissions. Although CFLs are more expensive than incandescent lights, they last longer and are cheaper in the long term. The main disadvantage of CFLs is that it contains mercury. According to researchers, breaking one fluorescent light bulb will release unsafe amounts of mercury vapor in the air. These mercury vapors can stay in the air for several weeks to months. Hence, be careful when handling and installing CFLs.

• Mercury thermometers and blood pressure apparatus. Some thermometers are made of glass with a silvery liquid inside, which is mercury. Even though this kind of thermometer is inserted in the mouth or rectum, it poses no harm because the mercury is contained inside the glass. However, should the thermometer break, this can release harmful mercury vapor to the surroundings. Fortunately, mercury-free thermometers are already available. Regarding mercurial blood pressure apparatus, these devices are still used by some hospitals and doctors because they are considered the gold standard in measuring the blood pressure. However, there are now alternative blood pressure equipment, such as the aneroid type and the LCD type, which do not use mercury. In summary, these medical devices generally pose no harm when used properly.

• Mercury-containing batteries. There are some special batteries that contain mercury, such as mercuric oxide batteries and button cell batteries. These batteries are typically used for watches, calculators, and some toys and games. Be careful that kids don’t handle these batteries. Dispose of these batteries in a sealed container.

• Dental fillings. Mercury-containing dental amalgams are widely used by dentists. They are considered safe, strong, long-lasting, and effective as tooth fillings. According to a review carried out by the Centers for Disease Control and Prevention, these amalgams are considered safe for the general population. However, certain individuals, like pregnant women, may opt for other types of amalgams. Consult your dentist about the advantages and disadvantages of different dental fillings used.

Who are at risk?

Some individuals are at higher risk for mercury poisoning than others. For example, the unborn fetus and young kids are more susceptible to the effects of mercury.

In cases of acute mercury poisoning, bring the patient to the hospital for emergency treatment. Those who ingested mercury may be given activated charcoal to soak up and remove the chemical from the body. Doctors also give supportive treatment for lung and kidney complications.

Prevention tips

1. Choose the kind of fish you eat. As a general rule, smaller fish, like those less than 12 inches long, are safer. These fish have lived in the sea for a shorter period, thus limiting the amount of mercury they have absorbed in their bodies. Fish species with the lowest levels of mercury are samaral, dilis (anchovies), hito (catfish), galunggong (mackerel), salmon, sardines, tilapia, and bangus (milkfish). Other safe seafoods are shrimp, squid, and crab. Limit eating these kinds of fish: tuna, lapu-lapu, and sea bass.

2. Whenever possible, use mercury-free thermometers and blood pressure apparatus. In several countries, mercury thermometers are now prohibited.

3. Be careful when handling compact fluorescent lights and some batteries. When these bulbs are intact, no mercury is released into the environment. Dispose of old bulbs carefully in a separate trash.

4. Follow safety precautions if you are working in a dental facility, a hospital or a chemical factory. Use personal protective equipment whenever available.

Although mercury poisoning is not that common, it is a serious condition that can lead to complications. In other countries, they have developed a collection program for these hazardous wastes. This is an area where the Philippines has yet to improve on.

In the meantime, be alert on the possible sources of mercury and take the necessary steps to protect your family. –Willie T. Ong, MD (The Philippine Star)