Marxism

Colin Herbst

Mrs. Schell

SBI4UO

Sunday, December 19, 2004

Mercury and its Effects on Humans

Today when people think of heavy metal, they think of numerous rock bands such as Guns n' Roses, AC/DC, or Led Zepplin. However the more health conscious person should think of heavy metals such as lead, cadmium, and mercury. The most common metal to come in contact with humans, with possibly the most serious effects, is mercury. Mercury is a natural substance that can be found in the environment. It is the only common metal that is a liquid at room temperature, but at high temperatures it can evaporate into a colourless, odourless vapour. For years, this type of mercury has been used in products such as thermometers, switches, batteries, jewellery, cosmetics and even dental fillings (VDH 2004). Although mercury use has decreased throughout the years, many households still contain products with mercury in them. The following paragraphs give reasons why the use of mercury has decreased throughout the years by describing the effects of mercury on the human body, how mercury gets in the human body, and the steps taken to prevent the effects of mercury on the human body.

The health effects of mercury exposure depend on several key factors, mainly the amount of mercury and the length of exposure. However, a person's general health, age, sex, diet, and lifestyle are also factors determining the overall effects of mercury on a person. Young children and foetuses are especially susceptible to mercury due to their developing organs. Mercury affects several systems and organs in the human body such as the nervous system, the digestive system, the immune system and the endocrine system, the respiratory system, the kidney, and the heart. Mercury has short-term and long-term effects for each system and organ. The following information on the short and long term effects of mercury inhalation are based on several occupational studies.

The effects due to short-term exposure to mercury are rarely seen anymore because of the strict rules used in workplaces where mercury is commonly used. However, in the past, short-term exposure to mercury caused harmful effects on the nervous, digestive, and respiratory systems. In most cases, exposure occurred when mercury was heated into a vapour, and therefore inhaled by the person.

The short-term effects on the nervous system usually include a fine tremor of the hands or fingers. Usually, numbness of major body parts follows. Short-term effects of the respiratory system include coughing, shortness of breath, tightness and burning pains in the chest and inflammation of the lungs (CCOHS 1998). Although the short-term or long-term effects of mercury on the digestive system are not well known due to the method of the mercury being brought into the system, symptoms presumable include sores of the mouth, inflammation and diarrhea. The symptoms are only presumed because of the limited number of cases where the employees have actually swallowed and digested mercury in its liquid form, however these symptoms have occurred to people who have inhaled mercury in its gaseous state (VDH 2004).

Much like the effects of short-term exposure to mercury, the long-term effects of mercury exposure are generally caused by inhalation exposure. However, liquid mercury as well as vapour is also absorbed through the skin in small amounts. These effects following absorption through the skin are usually similar to those reported of long-term inhalation exposure (CCOHS1998). The long-term inhalation of mercury affects the same systems in the body, only with more dramatic effects.

The long-term effects on the nervous system include muscle coordination, mood, behaviour, memory, and feeling and nerve conduction. These effects were reported in employees with moderately high or high exposure to mercury in occupations involving the use of mercury. The nervous system effects of mercury are sometimes referred to as "Mad Hatter's Disease"(CCOHS 1998). Very little information is available regarding the effects on the respiratory system from long-term exposure. Two studies reported persistent cough, while another study reported no symptoms what so ever (CCOHS 1998).

Long-term effects may also be observed in the kidneys and heart. A recent occupational study showed that increased levels of protein in the urine (also known as proteinuria) and increased levels of enzymes in the blood and urine are early symptoms of the effects mercury has on the kidneys (CCOHS 1998). Mercury may also have long-term effects on the heart, including increased blood pressure and/or heart rate. Two occupational studies have shown that employees exposed to low levels of mercury showed no change in blood pressure or heart rate, when examined by an electrocardiogram. However, a few studies where employees have been exposed to high levels of mercury show abnormal electrocardiogram results, increased blood pressure, and an increased heart rate. Thus, more deaths due to cardiovascular problems have resulted in some occupations where there is a high degree of mercury exposure.

Just like the health effects of mercury exposure vary for differences of overall health, sex, and age, the route of exposure does as well. There are several ways to be exposed to mercury such as breathing vapours, skin contact, eating contaminated fish, and from pregnant mother to fetus.

Fetuses and infants are especially susceptible to mercury exposure, which is believed to be a potential cause of movement and learning disabilities (WSDE 2004). The most likely route of human exposure to mercury as shown above is through inhaling mercury vapours. This type of exposure can come simply from a broken thermometer in the home. However it is not likely that the vapours from a broken thermometer will ever reach concentration levels high enough to harm a human, especially if the spill is cleaned up quickly and efficiently. Therefore, it is a lot more likely that reports of incidents where mercury vapours are inhaled come from workplaces rather than homes.

Since inhaling mercury vapours is not common, there must be another common source for humans to ingest mercury. Well, there is. Mercury occurs naturally in the environment. It enters the environment as a result of a normal breakdown of rocks and soil through exposure to wind and water (WSDE 2004). The release of mercury in the environment has remained fairly constant throughout the years, however the levels of mercury in the environment are slowly increasing. This is due to human activity through such things as

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