by James J. Galligan, Ph.D., Associate Chair,
Department of Pharmacology and Toxicology

The recent Associated Press news story (Monday, Jan. 11, 2010)  about the high levels of the heavy metal, cadmium, in children’s jewelry manufactured in China (http://abcnews.go.com/Health/WellnessNews/wireStory?id=9527916) is reminiscent of a story a few years ago about 1,4 butanediol in the kids toy called Aqua Dots (http://www.reuters.com/article/idUSN0741410820071108) which was also manufactured in China.  (You can also view an AP video report to the right of this post.)

1,4 butanediol is a precursor of the synthesis of gamma hydroxybutyrate (GHB) by nerve cells in the brain.  Of course GHB is best known as a “date rape” drug.  GHB causes the victims to pass out and to develop amnesia, particularly when GHB is consumed with alcohol.  Kids playing with Aquadots were at risk of accidentally ingesting GHB and this could have acute and chronic effects on the child’s nervous system.

Cadmium has shown up in children’s jewelry (bracelets, necklaces) as a replacement for lead.  The toxicities caused by

Associate Press image of Rudolph charm

Charms from bracelets tested between 82 & 91 percent cadmium.

lead are well known.  What is less well known is that cadmium may be more toxic than lead.

Cadmium is a divalent cation ion, meaning it has two positive charges.  Cadmium has deleterious effects on the development of the nervous system which makes it very dangerous to include in the manufacturing process of children’s toys.  Cadmium is used in metallurgy (hence its use in the manufacture of jewelry), nickel/cadmium batteries and it is also used as a stabilizer in plastics manufacturing.  Cadmium is also found in cigarette smoke.

Cadmium blocks calcium channels in nerve cells.  Calcium channels are a portal for calcium to enter nerve cells from the extracellular fluids and calcium is an important signaling molecule that regulates the activity of nerve cells and their growth and maturation.  Blocking calcium channels (as can occur with cadmium exposure) would prevent calcium from entering nerves cells and therefore disrupts the normal function and maturation of nerve cells.

Cadmium also disrupts the function of many enzymes the control growth of cells, and also blocks the activity of enzymes that are responsible for DNA repair.  Both of these actions contribute to the carcinogenic effects of cadmium toxicity.

All in all cadmium exposure is not good and its’ use must be carefully monitored.  Obviously, it has no place in the manufacturing process of children’s toys.

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