Anthropogenic cadmium loading

Cadmium occurs naturally as sulfide co-deposited with zinc, copper, and lead sulfides. It is produced as a by-product in above-mentioned metal processing. Similar to lead and mercury, this heavy metal has no known biological functions in living organisms, and accordingly its accumulation in food and water leads to undesirable consequences to biota. Cadmium toxicology is related to dangerous influence to CNS and excretion systems, firstly, on kidney. 

There are also natural geochemical anomalies where soils are enriched by cadmium, for example, in the central parts of Sweden. Here the cultivation of crops accumulating cadmium (grains, potato, some grasses) is not recommended. In the coastal marine areas the cadmium mobility in soils is stimulated by its complexation with chlorine. 

Food is the main source of cadmium input to human organisms, however the smokers take in a much larger amount of this element with tobacco smoke. The average period of cadmium storage in the human body is 18 years. 

The World Health Organization recommends setting the upper limit of cadmium uptake as 1 pg/day, however in some regions this value is exceeded due to both natural background and environmental pollution. 

Cadmium production is related to its use in electrochemical plants for metal galvanization (about 50%), for nickel-cadmium batteries and special alloys. 

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