Cadmium is a minor metallic element, one of the naturally occurring components in the earth’s crust and waters, and present everywhere in our environment. It was first discovered in Germany in 1817 as a by-product of the zinc refining process. Its name is derived from the Latin word cadmia and the Greek word kadmeia that are ancient names for calamine or zinc oxide.
Naturally-occurring cadmium-sulfide based pigments were used as early as 1850 because of their brilliant red, orange and yellow colors, and appeared prominently in the paintings of Vincent Van Gogh in the late 1800s. Germany was the first and only commercial producer of cadmium metal for industrial applications up until World War I. Thomas A. Edison in the United States and Waldemar Junger in Sweden developed the first nickel-cadmium batteries early in the 20th Century. However, the most significant early use of cadmium was as a sacrificial corrosion protection coating on iron and steel.
Exposure to certain forms and concentrations of cadmium is known to produce toxic effects on humans. Long-term occupational exposure to cadmium at excess concentrations can cause adverse health effects on the kidneys and lungs. Adverse human health effects have generally not been encountered under normal exposure conditions for the general population except in areas of historically high cadmium contamination. The potential risks from cadmium exposure have been extensively studied, and are now tightly controlled by occupational exposure standards, regulations for cadmium in ambient air, water and soil, and legislation covering cadmium emissions, labeling and disposal of cadmium-containing products, and impurity levels in other products such as fossil fuels, fertilizers and cement.