The Instances and Effects of Mercury Poisoning on the Human Body

Mercury is a naturally occurring heavy metal that is liquid at room temperature. Mercury most commonly affects the neurological, gastrointestinal, and renal organ systems (Olson et al., 2013). There are many ways one can be exposed to mercury, including vapor inhalation, ingestion, injection, and absorption through the skin (Olson et al., 2013). Mercury can be found in three forms: elemental mercury, inorganic salts, and organic compounds (Olson et al., 2013). Depending on the form of the mercury, the manner in which a patient has been exposed to mercury, and the symptomology presented, there are a number of various processes taking place within the body as the poisonous mercury takes effect.

Methylmercury, an organic compound, is by far the most lethal form as ninety-percent of ingested methylmercury is absorbed through the gastrointestinal tract and into the bloodstream - significantly altering digestive functions (Olson et al., 2013). The blood then carries the methylmercury throughout the entire body, causing rampant poisoning of numerous organ systems. Although ingested methylmercury is most common and the most lethal, it is not the only form of mercury poisoning. In order to best understand how mercury affects the body, it is important to note the various pathways of poisoning and the associated organ systems that can be affected. One must consider “the form of mercury, the dose, and the rate of exposure,” (Bernhoft, 2012, p. 1) which will be unique to each patient.

When mercury is in vapor form and it is inhaled, the primary organ affected is the brain (Bernhoft, 2012, p.1). When mercury is in the form of inorganic salts, the lining of the gastrointestinal tract and the kidneys are the primary organs affected (Bernhoft, 2012, p.1). Methylmercury, as discussed above, is highly permeable and can be transported all over the body, affecting numerous organ systems at once (Bernhoft, 2012, p. 1). Women who are pregnant must be extremely cautious because “elemental as well as organic mercury can easily pass the placenta and can accumulate in the fetus because the fetus is not able to excrete mercury” (Bose-O’Reilly et al., 2010, p. 8). Mercury exposure to fetuses, infants and children is compounded in potency due to the fact that growing children have smaller body masses than adults (Bose-O’Reilly et al., 2010, p. 1).

Mercury is so dangerous simply because it can go unseen and undetected. Mercury is odorless and invisible in most forms (Hightower, 2014). Except when mercury is in its most raw form as a shiny, bead-like mass of liquid, mercury is a stealthy poison. If a patient is exposed to mercury vapor in a large, single-instance dose, the likely result will be pneumonitis, inflammation of the lungs, which is lethal in extreme cases (Bernhoft, 2012, p. 1). If a patient has been exposed to smaller doses of mercury but over a longer period of time, more subtle symptoms can occur that may resemble other, more common illnesses (Bernhoft, 2012, p. 1).

The most common source of mercury exposure is mercury found in the food supply. For example, "organic mercury compounds, specifically methylmercury, are concentrated in… fish from contaminated waters" (Olson et al., 2013). When industrial wastes are dumped into water was such as rivers, lakes and bays, the natural organisms within the water such as algae, plankton, and waterweeds convert inorganic mercury into methylmercury (Olson et al., 2013). Small fish eat the plants and larger fish eat the smaller fish. When fishermen catch the larger fish to sell at market, people purchase fish to eat that is carrying mercury that originated from industrial wastes (Olson et al., 2013).

Mercury, while largely produced as a waste byproduct from industrial activities, also occurs in soil deposits (Bose-O’Reilly et al., 2010, p. 4). Mercury can accumulate in or on soil “from air, diffuse releases from waste products, such as batteries, switches, and medicinal waste, intended or unintended local releases from industry, spreading of sewage sludge containing contaminants on areas under cultivation, disposal on landfills, use of solid products from waste incineration, and coal combustion” (Bose-O’Reilly et al., 2010, p. 4-5). Children are especially susceptible to being exposed to mercury in the soil and on the surface of the ground due to the fact that children often play on the ground, fall, and generally enjoy outdoor rustic activities (Bose-O’Reilly et al., 2010, p. 6). Other sources of mercury that can lead to mercury poisoning are fluorescent light bulbs, dental amalgam, multidose activated vaccines containing ethyl mercury as a preservative, and measuring devices such as thermometers, barometers (Bose-O’Reilly et al., 2010, p. 5).

There are numerous cases of mercury poisoning that are being overlooked worldwide. For instance, while illegal in the United States and other developed countries, children are still used as cheap labor in mining in countries such as Botswana in Africa, Asia, and South Africa (Bose-O’Reilly et al., 2010, p. 6). In fact, “up to 1 million children are involved worldwide in any kind of mining” and many of these children have direct and prolonged contact with mercury (Bose-O’Reilly et al., 2010, p. 6). Additionally, inorganic mercury compounds are used for medicinal and cosmetic purposes due to their antiseptic, laxative, and diuretic properties (Bose-O’Reilly et al., 2010, p. 7). In some countries, mercury is still used as a key ingredient in skin-lightening creams and soaps (Bose-O’Reilly et al., 2010, p. 7).

The symptoms of mercury are as numerous as they are unpleasant. When inhaled, mercury poisoning can cause headaches, coughing, nausea, vomiting, a metallic taste in the mouth, chest pain, inflammation of the eye tissues, and a shortness of breath (Everett, 2012). As mercury poisoning worsens, patients may experience pneumonia, pneumonitis, and, in very severe cases, kidney and liver failure (Everett, 2012). Prolonged exposure to mercury poisoning (non-acute cases) can lead to tremors, memory loss, changes in personality, lethargy, insomnia, decreased motor capabilities, swelling of the gums, overproduction of saliva, and impairment of vision, hearing, and sight. (Everett, 2012).

While most symptoms of mercury poisoning are fairly common to other illnesses and diseases, there are three symptoms in particular that are unique to mercury poisoning (Olson et al., 2013). These symptoms do not occur in every patient who experiences mercury poisoning, but if they do occur, they can be extremely useful to note in the diagnostic process. The first unique symptom of mercury poisoning is called metal fume fever (Olson et al., 2013). Metal fume fever “occurs in the acute phase of mercury vapor toxicity and is manifested by fatigue, weakness, fever, chills, dizziness, headache, abdominal cramping, dyspnea [difficulty or discomfort when breathing], dysuria [painful urination], and ejaculatory pain” (Olson et al., 2013). The second symptom unique to mercury poisoning is called acrodynia, which is also known as pink disease (Olson et al., 2013). Acrodynia is considered to be an allergy to mercury and presents with specific skin conditions such as inflammation of fat cells in the palms of the hands and soles of the feet, a buildup of fluid in the hands and feet, and a rash with flaking of the skin (Olson et al., 2013). Acrodynia also includes symptoms of hair loss, itching, excessive perspiration, tachycardia, hypertension, photophobia, irritability, anorexia, insomnia, poor muscle tone, and constipation or diarrhea (Olson et al., 2013). Finally, the third pattern of symptoms special to mercury poisoning is called erethism, which is “a constellation of irritability, excitability, anxiety, insomnia, and social withdrawal (Olson et al., 2013). Erethism is most commonly seen in patients who have been exposed to chronic, long-term exposure to inorganic mercury Olson et al., 2013).

Because many of the symptoms that are caused by mercury poisoning can also occur because of other illnesses such as cancer, neurological damage, infection, and drug side-effects, a proper diagnosis is crucial. When looking for signs of mercury poisoning, many doctors will look at a patient’s fingernails (Everett, 2012). Mercury poisoning causes a line that runs parallel to the cuticle to form in the nail (Everett, 2012). Doctors will likely take blood and urine samples from a patient and send them for analysis with the specific note of testing for mercury poisoning (Everett, 2012). Proper tests of blood and urine can tell physicians the form of mercury to which a patient was exposed (Everett, 2012). The quantities of mercury in a patient’s system, coupled with information based on the severity of a patient’s symptoms can indicate whether the patient has been exposed acutely or chronically and what the dosage of poisoning was (Everett, 2012).

There are several treatments doctors may use to help cure a patient of mercury poisoning. Initially, doctors may prescribe chelation therapy, which “is used to increase urinary elimination of mercury and will reduce the amount of mercury in the blood” (Everett, 2012). If the patient has been exposed to mercury for prolonged periods of time, doctors will likely prescribe dialysis to filter the mercury out of the patient’s blood stream (Everett, 2012). Prevention is the best form of treatment for a community at risk of mercury poisoning. Patients should be encouraged to monitor the recorded levels of mercury in the areas where they get their food – including fish and agricultural sources (Everett, 2012). Direct patients to the Food and Drug Administration website for frequent updates on hazardous mercury levels and news about possible contamination of food sources (Everett, 2012).

Mercury poisoning is extremely dangerous and can cause a myriad of various symptoms. The mercury itself can be completely invisible to the naked eye and may be in places one would never think to look, such as in freshly harvested foods or common soil. Unfortunately, mercury poisoning can be difficult to diagnose due to the fact that the symptoms can mimic those of other serious physical illnesses and mental health issues as well. However, if mercury poisoning is properly diagnosed, it is treatable and patients can typically recover to live long, healthy lives in most cases.

References

Bernhoft, R. A. (2012). Mercury toxicity and treatment: A review of the literature. Journal of Environmental and Public Health, 2012, pp. 1-10.

Bose-O’Reilly, S., McCarty, K. M., Steckling, N., & Lettmeier, B. (2010). Mercury exposure and children’s health. Current Problems in Pediatric and Adolescent Health Care, 40(8), pp. 186-215.

Everett, M. (2012). Health effects of mercury. The Science and Education Resource Center at Carleton College. Retrieved from http://serc.carleton.edu/NAGTWorkshops/health/case_studies/mercury.html

Hightower, J. (2014). Learn about mercury and its effects. Natural Resources Defense Council. Retrieved from http://www.nrdc.org/health/effects/mercury/effects.asp

Olson, D. A., Brenner, B. E., Corden, T. E., Diner, B. M., Harchelroad, F., Mullins, M. E., Talavera, F., Tan, D. K., Tarabar, A., Tucker, J. R., VanDeVoort, J. T., Windle, M. L. & Ramachandran, T. S. (2013). Mercury toxicity. MedScape. Retrieved from http://emedicine.medscape.com/article/1175560-overview