Finding Lead in Toys

The story on lead in toys had seemingly gone away, but recently on NPR it resurfaced again. The Consumer Products Safety Commission has plans to increase regulations on consumer products such as toys. Until the safety issues with toys are cleared up, companies will be continued to be penalized for any lack of vigilance.

Curious about the current state of research and testing toys, I looked into high tech, rapid and accurate ways that lead can be tested for in metal and plastic.

Initial investigation led to the discovery that many do-it-at-home kits that test for lead available at home improvement stores are not accurate. As stated in an NPR story in December there are a few kits that test for lead on the surface of toys, but not embedded lead. These tests are not recommended by the Consumer Product Safety Commission.

The best test for embedded lead is state-of-the-art, fast and portable XRF. XRF is shorthand for X-ray fluorescence. X-ray is the type of radiation that we are familiar with when have our teeth X-rayed by a dentist. It is a high energy form of light and part of what scientists call the electromagnetic spectrum and not visible by eye. Fluorescence, on the other hand is visible light that is emitted when light interacts with an atom’s electrons making them energetically excited. In this excited state light is emitted and the electron returns to its normal state. The emitted light is fluorescence. The fluorescence wavelengths are characteristic to the identity of the atom or molecule.

XRF is a device that uses X-ray light to produce fluorescence from an atom or molecule. In the case of toys, X-ray light excites the electrons in lead and will emit specific colors of fluorescence that are a fingerprint for identifying that atom. XRF not only gives information about the surface of the toy but also what lead contaminants might be hidden below the surface. Much like how an X-ray can penetrate the surface of your tooth to find a cavity, lead fluorescence is extremely specific for identification and penetrates below the surface of the toy.

Although XRF may be out of reach to the average consumer, these hand-held devices are very useful for field work, in factories and to toy companies themselves for testing products for toxic metals and chemicals. In the hands of the skilled scientist, XRF can give detailed information about what metals are present in a toy or other product. With high tech tools like this available on the market, the testing of lead in toys should become more facile and their use more widespread.