Why Is Cadmium So Dangerous?

Cadmium, a natural element in the Earth's crust, is present in miniscule amounts in all soil and rocks. (Image credit: nj.us)

The discovery of cadmium in McDonald's "Shrek Forever After" movie-themed drinking glasses has led to a nationwide recall and fear over how the toxic metal could affect young children.

"A very small amount of cadmium can come to the surface of the glass, and in order to be as protective as possible of children, CPSC and McDonald's worked together on this recall," said U.S. Consumer Product Safety Commission (CPSC) spokesman Scott Wolfson.

"Long-term exposure to cadmium can cause adverse health effects," according to the official recall notice from the CPSC. In addition, according to the CPSC statement, the amount of cadmium found in the cups was "slightly above the protective level currently being developed by the agency."

Cadmium, a natural element in the Earth's crust, is actually present in miniscule amounts in all soil and rocks, according to the Agency for Toxic Substances and Disease Registry (ATSDR). Because it does not corrode easily, it is primarily used in batteries. It is also used in metal coatings, platings, pigments and as a stabilizer for plastics.

In the case of the McDonald's glass cups, cadmium was used in the red and yellow pigments on the cup's painted designs, according to McDonald's USA spokesman Bill Whitman. Long-term exposure to cadmium, even to low levels, poses a potential threat to a child's health as the toxic metal may seep from the cup and enter the body.

A known carcinogen, or cancer-causing agent, chronic cadmium exposure has been shown to primarily cause severe kidney problems, including kidney failure, and, secondarily, bone softening. Previous recalls of children's products found to contain large quantities of cadmium include jewelry and toys, according to the ATSDR.

Cadmium is also present at alarmingly high levels in cigarette smoke . In fact, a direct measurement of cadmium levels in body tissue shows that smokers have roughly twice the amount of the toxic metal in their bodies as do non-smokers, according to the ATSDR.

Remy Melina was a staff writer for Live Science from 2010 to 2012. She holds a bachelor’s degree in Communication from Hofstra University where she graduated with honors.