It has come to my attention that the Swedish chemical authority have decided to inspect some items which might be known as “adult toys” or “sex toys”. I do have a problem with this use of the word “adult” as some of the things in “adult entertainment” sector are anything but adult. To me adult means mature, sensible, reasonable and decent. The true meanings of these four words “mature, sensible, reasonable and decent” are often polar opposites of some of the things in the “adult entertainment industry”. But I think that we will leave this topic alone.
What Kemikalieinspektionen did was to consider a total of 44 items from 16 compaines, now I am not going to discuss the intended use of the items or what they are. If you feel the urge to read that then I suggest you look elsewhere. What I am going to discuss is some of the chemistry involved.
Now the Swedish body choose to consider “phthalates, short chain chlorinated paraffins, azo dyes, nickel and the metals and flame retardants that are restricted for electrical products“. While the topic and the items might be controversial I think that it was a reasonable choice to make.
Now the start of the method explains how XRF was used to screen for a range of harmful metals, it will also detect bromine. But care needs to be taken with the measurement of bromine by XRD as one of the L lines (1.48043 1.48043 1.52590 keV) for bromine are very close to the line for aluminium (K lines at 1.48670, 1.48627 and 1.55745 keV). The items which were regarded as being interesting were then sent for further examination.
The problem with the report was that it was not totally clear which analytical method was used to determine the metal or the organics in the items. What was found in one study by Gerald Fowles which is mentioned in the wonderful book “Chemistry in the Marketplace” is that the nature of the mechanical pretreatment before leaching will alter the amount of a metal which can be released from an item. The key message is that chewing a plastic children’s toy was very effective as a means of releasing the metals in them while other mechanical pretreatments tended to lock in the metals. Also sucking on toys is not that dangerous but chewing and gnawing at them does release cadmium.
He also found that the use of hydrochloric acid which contains mercury(II) chloride as a preservative also inhibited the release of cadmium from cadmium sulfide and cadmium selenide. The reason is that an even more insoluble layer of the mercury chalcogenide will form on the surface of a pigment particle thus preventing any further reaction. It is a bit like the problem of sulfuric acid and marble chips, there a layer of insoluble calcium sulfate forms on the marble chips thus preventing any further reaction from occuring.
Gerald Wilfred Albert Fowles also did some very interesting work on lead and chromium in children’s comic books when he was at Reading University in the 1970s. In Diana F. Eaton, Gerald W. A. Fowles, Michael W. Thomas, G. Brian Turnbull, Environ. Sci. Technol., 1975, 9 (8), pp 768–770 he reports on how much lead and chromium can be leached from comic books when they are leached in a simulated stomach acid.
A different approach would be to use a wet combustion of the plastic by digesting it in a Parr bomb with nitric acid. Here the plastic would be totally degraded by the oxidant (nitric acid). Then we would get all of the metal contents released from the object. It is interesting to note that simple burning can result in the loss of some semivolatile metals such as lead.
What would have been interesting to know is if the items were leached with some chemical reagent or were they digested / burnt to release the entire inventory of the metals. One interesting problem is that while when PVC and latex are heated under oxidizing conditions that they are converted totally into gases, when silicone is burnt it forms a large amount of silicone dioxide. It is possible that attempts to liberate metals from silicone objects will be hampered by the formation of silica. In the worst cases the silica may form a crust over the metals thus locking them in.