Mercury (Hg), often known as quicksilver, is a chemical element that belongs to Group 12 of the periodic table and is a liquid metal. Mercury is a component found in a variety of devices, including thermometers, barometers, manometers, sphygmomanometers, float valves, mercury switches, mercury relays, fluorescent lights, and more. Any form of mercury is harmful, and the GI tract, renal, and nervous systems are the most often affected organ systems by mercury toxicity. Ingestion of mercury, inhalation of mercury vapor, and skin absorption of mercury can all result in mercury poisoning. This article will explain to you about Mercury Toxicology Effects which will help prepare the Environment Syllabus for the UPSC Civil Service exam.

Why is Mercury Present in the Environment?

• Natural events like the weathering of rocks, volcanic eruptions, geothermal activity, forest fires, etc. release mercury into the atmosphere.
• In addition to these natural processes, human activity also releases mercury.
• Mercury has been utilized for a variety of applications for hundreds of years due to its many special qualities.
• Mercury is a persistent substance that can move between the air, water, and soil after it has been discharged into the environment.
• Methylmercury is formed when mercury enters living things and subsequently concentrates up the food chain.

Exposure to Mercury

• All people are subject to some mercury exposure. Most individuals are exposed to low quantities of mercury, generally through chronic exposure (continuous or intermittent long-term interaction).
• However, some individuals are acutely exposed to elevated mercury levels (exposure occurring over a short period of time, often less than a day).
• Mercury exposure as a result of an industrial accident is an illustration of acute exposure.
• Health consequences and intensity depend on a number of factors, including:
• Type of Mercury Concerned;
• Dosage;
• Age or Developmental Stage of the Exposed Person (the fetus is most susceptible);
• Duration of Exposure;
• Route of exposure.

Mercury - Harmful Effects

• Mercury has an impact on the immune, neurological, and digestive systems. Additionally, it harms the kidneys, lungs, eyes, skin, and other organs.
• The brain damage suffered by victims cannot be repaired, and they may experience memory loss or language difficulty.
• Since even small levels of elemental mercury can have negative consequences on health, there is no established safe exposure level for people.
• The most susceptible groups to the negative effects of mercury include children, newborns, and fetuses.
• Because mercury is easily transmitted around the planet by the environment, its harmful effects can be felt even in remote areas.
• Acrodynia (also known as a pink disease), Hunter-Russell syndrome, and Minamata disease are just a few of the illnesses that can be brought on by mercury exposure.
• A loss of coordination, sensory impairment (vision, hearing, speech), and abnormal sensation are common symptoms.
• The specific toxin, the dose, the exposure method, and the length of exposure all affect the kind and severity of the symptoms that are displayed.
• Even at low concentrations in the range of 0.7-42 g/m3, case-control studies have demonstrated impacts on employees with continuous exposure to mercury vapour, including tremors, reduced cognitive function, and sleep disturbance.
• According to a study, chest pain, dyspnea, coughing up blood, hemoptysis, impaired pulmonary function, and signs of interstitial pneumonitis were all experienced after an acute (4–8 hour) exposure to calculated elemental mercury values of 1.1–44 mg/m3.
• It has been demonstrated that acute mercury vapor exposure has substantial effects on the central nervous system, including psychotic episodes marked by delirium, hallucinations, and suicidal ideation.
• Wide-ranging functional disturbances, such as erethism, irritability, excitability, excessive shyness, and sleeplessness, have been linked to occupational exposure. With prolonged exposure, a mild tremor may progress to intense muscle spasms.
• The hands are initially affected by tremors, which later spreads to the mouth, lips, and eyelids.
• The more subtly manifested symptoms of erethism, such as weariness, irritability, memory loss, vivid dreams, and sadness, have been linked to long-term, low-level exposure.

Mercury Exposure - Reduction

• Promotion of Clean Energy Use: A significant source of mercury is the burning of coal for energy and heat. When coal is burned in coal-fired power plants, commercial boilers, and home stoves, it releases mercury and other dangerous air pollutants.
• Elimination of Mercury Mining: Since mercury is an element that cannot be destroyed, it can be recycled for other vital purposes, negating the need for additional mercury mining.
• Mercury usage is extremely dangerous in small-scale and artisanal gold mining, and it has serious negative health consequences on vulnerable communities.
• There is a need to promote and develop non-mercury (non-cyanide) gold extraction methods, and when mercury is still used, safer work procedures must be followed to reduce exposure.
• Reduction of Mercury in Products: To lower mercury levels in products or phase out mercury-containing products, a variety of activities are being done.
• Alternative devices are replacing mercury-containing thermometers and sphygmomanometers in the medical field.
• Nearly all nations utilize dental amalgam. According to a 2009 WHO expert consultation, a global ban on amalgam in the near future would be challenging for both public health and the dental health industry, but a phase-down should be pursued.
• It can be done by promoting disease prevention and alternatives to amalgam, research and development of affordable alternatives, education of dental professionals, and public awareness raising.
• Some skin-lightening creams include substantial levels of inorganic mercury. Because they are harmful to human health, many nations have prohibited skin-lightening products that contain mercury.

Minamata Convention on Mercury

• A global agreement known as the Minamata Convention on Mercury was made to protect the environment and human health against anthropogenic releases and emissions of mercury and its compounds.
• The Minamata Convention was adopted in 2013 in Kumamoto, Japan. The convention has the name of the Japanese town of Minamata.
• Given that mercury poisoning had a severe impact on the city, this naming is significant symbolically.
• Currently, there are 137 parties to Minamata Convention.
• The Minamata Convention includes a ban on new mercury mines, the phase-out of existing ones, the phase-out, and phase-down of mercury use in a variety of products and processes, emission control measures for air, land, and water, and regulation of the informal sector of artisanal and small-scale gold mining.
• The Convention also addresses interim mercury storage and disposal once it has become waste, mercury-contaminated sites, and health concerns.

What is Minamata Disease?

• Minamata disease is a neurological condition brought on by severe mercury poisoning.
• In the technical sense of the word, Minamata disease is not truly a disease; rather, it is a neurological syndrome brought on by environmental and industrial pollution.
• This indicates that the central nervous system is impacted by pollutant poisoning.
• Methylmercury is the specific pollutant that causes this condition.
• Ataxia, numbness in the hands and feet, generalized muscle weakness, loss of peripheral vision, and damage to hearing and speech are some of the signs and symptoms.
• In severe cases, coma, death, paralysis, and insanity all occur within a few weeks of the commencement of symptoms.
• Cerebral palsy may result from a congenital type of illness that can also harm fetuses in the womb.

Conclusion

The World Health Organization (WHO) has published information on the effects of various forms of mercury on health, guidelines for identifying populations at risk of mercury exposure, methods for reducing mercury exposure, and recommendations for the replacement of mercury-containing thermometers and blood pressure gauges in medical facilities. In addition to leading initiatives to advance responsible handling and disposal of medical waste, WHO has aided in the creation of a blood pressure monitor that is inexpensive, reliable, and free of mercury.

FAQs

MCQs

1. Which of the following is a primary source of mercury contamination in the environment?

A) Agricultural run-off

B) Coal burning

C) Oil spills

D) Plastic waste

2. What is methylmercury?

A) A form of mercury found in vaccines

B) An inorganic compound of mercury

C) A highly toxic organic form of mercury

D) A compound used in pesticides

3. Which of the following can be a consequence of mercury exposure?

A) Increased heart rate

B) Neurological damage

C) Improved cognitive function

D) Reduced fertility

4. What global treaty aims to reduce mercury emissions and releases?

A) Kyoto Protocol

B) Paris Agreement

C) Minamata Convention on Mercury

D) Basel Convention

5. What is the main concern related to mercury contamination in aquatic systems?

A) It disrupts plant growth

B) It causes bioaccumulation in fish

C) It increases the acidity of water

D) It reduces water clarity

GS Mains Questions and Model Answers

Q1: Discuss the environmental and health impacts of mercury contamination. What measures can be taken to mitigate these effects?

Answer: Mercury contamination, especially in its methylmercury form, poses serious environmental and health risks. It accumulates in aquatic food chains, affecting fish and other marine life, and is toxic to humans, causing neurological damage, developmental defects, and kidney problems. To mitigate these impacts, measures such as reducing industrial mercury emissions, improving waste management practices, using mercury-free technologies, and enforcing regulations like the Minamata Convention are essential. Additionally, public awareness and monitoring of mercury levels in food chains can help reduce human exposure.

Q2: Evaluate the effectiveness of the Minamata Convention on Mercury in addressing mercury pollution globally. What challenges remain in its implementation?

Answer: The Minamata Convention on Mercury, signed in 2013, has been a landmark global effort to reduce mercury emissions and mitigate its impact on human health and the environment. The convention has led to some success in curbing mercury use in products like thermometers and batteries, and in promoting the development of mercury-free technologies. However, challenges remain in the full implementation of the convention, including lack of compliance in developing countries, inadequate monitoring, and the illegal trade in mercury. Strengthening global cooperation and ensuring financial and technical support for developing countries are key to overcoming these challenges.

Q3: Analyze the role of industrial activities in mercury pollution. How can industrial regulations be improved to reduce mercury emissions?

Answer: Industrial activities, especially coal burning, mining, and waste disposal, are significant contributors to mercury pollution. These activities release mercury into the atmosphere, water bodies, and soil. Industrial regulations can be improved by enforcing stricter emission standards, adopting cleaner technologies, promoting the use of renewable energy, and ensuring proper waste management practices. In addition, encouraging industries to transition to mercury-free processes and invest in research for alternative materials will reduce the global mercury burden and protect ecosystems and human health.

Previous Year Questions on Mercury 

1. UPSC CSE 2020

Question: Discuss the impact of industrial pollution, including mercury contamination, on the environment. What steps should be taken to control industrial emissions?

Answer: Industrial pollution, including mercury contamination, causes severe harm to ecosystems, particularly aquatic environments. Mercury bioaccumulates in food chains, affecting both wildlife and humans. To control industrial emissions, governments should enforce stricter pollution control laws, promote cleaner technologies, and encourage the adoption of sustainable practices by industries. International agreements like the Minamata Convention play a crucial role in setting global standards and ensuring compliance.

2. UPSC CSE 2019

Question: Evaluate the role of global conventions in controlling mercury pollution. How effective has the Minamata Convention been in addressing mercury-related health and environmental issues?

Answer: Global conventions like the Minamata Convention are vital in controlling mercury pollution by setting legally binding standards and encouraging global cooperation. The convention has been successful in reducing mercury use in several products and in limiting emissions from industrial sources. However, challenges such as inconsistent implementation across countries and the ongoing illegal mercury trade highlight the need for improved monitoring and stronger enforcement mechanisms to make the convention more effective in the long run.