Long Term Effects Of Mercury Exposure example essay topic

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, odour less 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 foetus es 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 (CCOHS 1998). 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) 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 mining and factories burning fuels such as coal. Most of the mercury released from human activities is released into air, through fossil fuel combustion, mining, smelting and solid waste combustion. Some forms of human activity release mercury directly into the soil or water, for instance the application of agricultural fertilizers and industrial wastewater disposal.

All mercury that is released in the environment will eventually end up in soils and / or water (WSDE 2004). Once mercury has reached water or soil, microorganisms convert it to methyl mercury, another from of mercury that can be absorbed quickly by most organisms and is known to cause nerve damage. Fish are organisms that absorb great amounts of methyl mercury from water everyday. As a consequence, methyl mercury can accumulate in fish and in the food chains that are associated with fish (WSDE 2004). The following diagram illustrates how methyl mercury accumulates at the higher levels of the food chain and becomes concentrated in fish and the humans that eat them.

1. Tiny animals and plants known as plankton take up methyl mercury in the water and sediment. 2. Minnows and juvenile fish eat large quantities of plankton over time. 3. Larger predatory fish consume many smaller fish, accumulating methyl mercury in their tissues.

The older and larger fish, the greater the potential for high mercury levels in their bodies. 4. Fish are caught and eaten by humans and animals, causing methyl mercury to accumulate in human tissues. (Mer cola 2004) An example of the above diagram and methyl mercury in the water can be found when looking back at a 1932 incident in Minamata, Japan. Inorganic mercury was being used in a Japanese factory, and it was discharged into a nearby bay as wastewater. Fish and other creatures in the sea were soon contaminated and eventually residents of this area who consumed the fish suffered from mercury poisoning, later known as the Minamata Disease.

The disease was first detected in 1956 but the mercury emissions continued until 1968. Even after the emissions of mercury stopped, the bottom sediment of the bay still contained high levels of mercury. This occurrence proved to be a turning point towards progress in environmental protection and mercury awareness. (CCOHS 2004) Since there is a cause and effect of mercury exposure in humans, there must also be actions taken to decrease the likelihood of the cause, and reduce the effect of exposure to mercury. The following paragraphs will describe the actions taken by different environmental associations, and what individuals can do to reduce the cause and effect of mercury exposure. For the Minamata Disease incident, various measures were taken to deal with the contamination of the bay.

Measures such as environmental control, which included cessation of the mercury process; industrial effluent control, environmental restoration of the bay; and restrictions on the intake of fish from the bay. Since this was a major turning point towards progress in environmental protection measures, many other countries including The United States and Canada, have taken their own measures in monitoring mercury levels in fish and water. Groups such as the Western Fish-boat Owners Association, The Pacific Coast Federation of Fisherman's Association, and the Minnesota Pollution Control Agency, have all worked on keeping our country free from the effects of mercury by constantly performing studies and tests of the mercury content in our oceans' fish. Using the Minnesota Pollution Control Agency as an example, one can see how far measures have been taken to decrease human contact with mercury. Minnesota has taken a number of steps to keep mercury out of the environment, including: .

Minnesota was the first state to prohibit using mercury in dry-cell batteries; . The mercury from thermostats, thermometers, gauges, medical and scientific equipment, electrical devices, motor vehicles and household appliances must be removed for reuse or recycling before these products can be disposed of or scrapped; . Fluorescent lamps must be disposed of at special facilities licensed to recycle the mercury; . Certain toxic substances, including mercury, are prohibited in inks, dyes, pigments, paints or fungicides as well as in any packaging products; . MPCA permits for incinerators include limits on the amount of mercury they may release.

(MCPA 2004) Together the causes of mercury, and the effects mercury has on the human body prove that mercury is a dangerous metal. The actually effects of mercury and how they get into the human body still overshadow the actions taken to avoid mercury and its effects. The above paragraphs show good reason why the numbers of products in the household containing mercury are decreasing as the years go by. They also provide reasonable doubt as to why such a potentially dangerous metal was ever used in common household products.

Such a question may never be answered, however many people may sleep better at night knowing that the question will never have to be answered, sleeping in a mercury free home.