Mercury and the Environment
Mercury is ranked third after Arsenic and Lead which cause the greatest harm to the environment as well as human health. It is naturally present in the atmosphere in the form of vapor or gas, but man-made mercury is the major cause of concern. The two- thirds of the mercury in the atmosphere are generated by human activities and leads to degradation of the environment.
Mercury basically is present in the environment in three forms i.e. elemental mercury, organic and inorganic mercury. The elemental mercury, which is known by other names like liquid mercury, silver liquid which has low vapor pressure and can be easily converted into vapor in room temperature. Again, it is found naturally in the Earth’s crust and come out through volcano eruptions, burning of oil, etc which returned back to soil and water through dust, rain and gravitational force. But the human activities have increased the amount of liquid mercury in the environment. It is commonly used in barometers, thermometers, fluorescent bulbs (CFLs), Sphygmomanometers (blood pressure measuring device) which on breaking releases the liquid mercury and when not acted upon can turn into odorless, invisible vapor and mix into the environment.
The more the mercury enters the atmosphere, the more harmful it could be for the environment. The atmospheric mercury, as stated above, comes down to earth and soil thorough dust, rain, snowfall and gravitational force. It also gets mixed in water bodies. Being a low water soluble and a lipid soluble, it is absorbed by the fish and birds intestines. According to a test, around 95% of the mercury is usually absorbed by the body and that is why it gradually accumulates. The bioaccumulation of mercury in fish and a bird's body eventually ends up in the higher organisms, depended on these lower animals. The mercury enters into the food chain and reaches to the human body. The people who eat seafood, freshwater fishes are more prone to mercury exposure. The diseases which occur due to the excessive mercury exposure is known as the "Minamata Disease". This name has been given after the incident of Minamata Bay of Japan in the 1950s where the industrial effluents carrying tons of mercury were dumped into Minamata bay causing huge problems in humans, aquatic life and birds.
The major disease or harmful effects of liquid mercury or its compound impacts the nervous system i.e. the brain and the spinal cord. It affects the learning skill of the child whose brain is sensitive in comparison to an adult, whereas in adults it hampers the growth of the healthy brain, results into poor visibility/eyesight, hearing and listening abilities. It also impacts the limbs making them numb and stressed. The arms shake, it loses control and a human can even not walk properly.
Some survey shows that it doesn't affect the plant life and that is why it poses a great risk to birds and animals. The liquid mercury is very harmful to the environment and stays in the atmosphere for an extremely long time.