Human activities affecting biota

Mercury is a toxic substance that, through human and natural activities, cycles through the atmosphere, hydrosphere, and ecosphere affecting the health of both humans and wildlife. It enters the environment naturally through erosion, fire, and volcanic processes, as well as a result of human industrial practices. The human activities such as combustion, smelting, and mining have elevated global mercury levels to approximately three times those found before industrialization. Once released, mercury persists in the environment where it circulates between air, water, sediments, and biota in various forms. Mercury is present everywhere in the environment. The level of Hg in air varies from 0.5 ng/m3 to 10 ig/m3. 

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