Metallic Demise
Metals are found everywhere and some are essential for life. Steel, Iron, Aluminum, Copper, Brass, and Zinc are all metals, just to name a few. But did you know metal can be found not only in the earth and water, but also in the air?
True Topic
Although we will be talking about metals and its effect on the health of the environment, I would like to clarify the topic at hand. The metal we will be discussing is mercury and the effect it has on the environment. In the next few sections, I will help give you some intel as to what mercury really is and some history behind it because I think it’s pretty interesting!
Mercury: The Liquid Metal (Part I)
Mercury has many forms. These consist of the elemental form (liquid mercury), inorganic form (the type where people may be exposed through their occupation), and organic (the type where people may get exposed through their diet). The different forms that mercury can take effects their level of toxicity on the nervous, digestive, and immune systems as well as organs such as the lungs, kidneys, skin, and eyes.
Mercury is a natural element that can be found in the earth’s crust. It is released into the environment due to volcanic activity, rock weathering, and human activity (human activity is what we will be focusing on here). Human activity as of right now is the main cause of mercury release into the environment with activities such as coal-fire power stations, residential coal burning for heating and cooking, waste incinerators, industrial processes, and metals contributing.
Mercury: The Liquid Metal (Part II)
There is one form of mercury that I did not state yet and that is methylmercury. This form exists due to mercury being transformed in the environment because of naturally occurring bacteria. So why is methylmercury bad? Methylmercury can bioaccumulate (occurs when an organism contains higher concentrations of the substance than do the surroundings) particularly in shellfish and fish. Not only that, it can also biomagnify. This means that organisms higher up in the food chain tend to have higher mercury levels due to them constantly eating many smaller organisms that have acquired mercury through their own consumption.
Mercury: The Liquid Metal (Part III)
Okay, now time for some history regarding mercury.
Mercury was known to both the ancient Chinese (used as a contraceptive) and Hindus before 2000 BC and the Egyptians in 1500 BC. It was previously used to forma amalgams of other metals around 500 BC with the Greeks using it in ointments and the Romans using it in cosmetics (ouch). Believe it or not, it wasn’t until 1991 that the use of mercury in paint was phased out in the United States! Not only that, mercury is still used today by artisanal small-scale gold mining operations today, exposing over 10 million workers to mercury and releasing around 650-1,000 tons of mercury annually into the environment!
What about Mercury in the Air?
Human activity is not solely to blame for airborne mercury as this can be caused from both volcanoes and forest fires, but human activities are widely accepted to contribute the most to the release of mercury in the environment regardless. Burning of coal, oil and wood as fuel can cause mercury to go airborne in addition to burning mercury-containing waste. Once the mercury is in the air, it can fall to the ground in raindrops or be present in fog. The amount of mercury deposited in an area is dependent on the quantity of mercury release from local, regional, national, and international sources.
Health Effects
According to the World Health Organization, elemental and methylmercury are both toxic to the central (brain and spinal cord) and peripheral (the nerves that branch out from the brain and spinal cord) nervous systems. The inhalation of mercury vapor (airborne mercury) can cause potentially harmful effects on the nervous, digestive, and immune systems, and on the lungs and kidneys. For these reasons, high concentrations of mercury can be fatal to the organism.
In fact, mercury can impact the overall health of the organism to the point that it can be observed! Symptoms of high mercury includes tremors, insomnia, memory loss, and neuromuscular effects. Researchers are currently measuring such effects and the overall health of ecosystems by gathering hair samples to find the level of mercury in the organism’s system. Pretty wild!
Mercury on the Health of Ecosystems
Now for the final question, how does mercury ultimately affect the health of an ecosystem? Let’s start from what we know about bioaccumulation and biomagnification. Just knowing about these two terms will tell us that predators at the top of the food chain (apex predators) are at higher risk for developing the health issues stated in the previous section. Apex predators are crucial as they help to keep the whole ecosystem in check. This is due to the domino effect. If the apex predator population perishes due to mercury poisoning, then that would cause the mesopredator population to overhunt certain populations of prey over others. This why the toxic element mercury can be detrimental to the environment.
I hope you all learned a bit more about mercury (a really interesting element but an unquestionably dangerous one). Make sure to keep on staying safe and have a great day! :)
Citations:
[1] Czaika, Ellen, et al. Mercury Science and Policy at MIT, 15 Jan. 2013, https://mercurypolicy.scripts.mit.edu/blog/?p=367.
[2] EPA, Environmental Protection Agency, https://www.epa.gov/mercury/basic-information-about-mercury#:~:text=The%20burning%20of%20coal%2C%20oil,as%20%E2%80%9Cair%20deposition%E2%80%9D.
[3] Maes, Jonathan. “18 Different Types of Metal (Facts and Uses).” Make It From Metal, 19 Oct. 2021, https://makeitfrommetal.com/different-types-of-metal-facts-and-uses/.
[4] Mark Winter, University of Sheffield and WebElements Ltd. “Mercury: Historical Information.” WebElements Periodic Table " Mercury " Historical Information, https://www.webelements.com/mercury/history.html#:~:text=Mercury%20was%20known%20to%20ancient,those%20using%20it%2C%20in%20cosmetics.
[5] Mercury's Harmful Effects.” National Wildlife Federation, https://www.nwf.org/Magazines/National-Wildlife/2013/DecJan/Conservation/Mercury-and-Wildlife#:~:text=Mercury%2C%20which%20can%20adversely%20alter,birds%2C%20including%20loons%20and%20eagles.