Undead Bad Science
The dreadfully inept "study" of mercury in the hair of autistic children - saved as momentos of their first haircut - by Holmes, Blaxill and Haley (2003) continues to spread misinformation and confusion. A quick check on "Web of Science" revealed that it had been cited in other papers fifteen times! Of course, it should come as no surprise that at least six of those citations were in articles by the dynamic duo of pseudoscience, Geier and Geier (see here and here, also here, here, here and here).
In a nutshell, the Holmes et al "study" compared the mercury in the "first baby haircut" hair of 94 autistic children and 45 "neurotypical" controls. Disregarding so many procedural, technical and analytical flaws that they almost defy counting, the "data" they came up were these:
Autistic children's hair mercury levels: 0.47 ppm (+/- 0.28 ppm)
Control children's hair mercury levels: 3.63 ppm (+/- 3.65 ppm)
Now, Holmes (a radiation oncologist who was in "alternative" medical practice at the time), Blaxill (an MBA) and Haley (a somewhat conflicted PhD chemist) concluded that, since the autstic children had lower hair mercury than the controls, that autistic children were unable to excrete mercury.
Mind you, they offered no data to support that startling (if not ridiculous) conclusion, nor does anything known about mercury "excretion" in hair support that line of "reasoning". As far as I can tell, they just made it up rather than face what the data (such as it was) told them - that mercury had nothing to do with autism (actually, the data suggest that mercury might protect children from autism - another unlikely possibility).
Now, come along with me for a minute as we take a look at another study of hair mercury. This study, published in 2004, was part of the National Health and Nutrition Examination Survey of 1999-2000 and looked at the hair mercury levels of 838 "normal" children ages 1 - 5. This is roughly the same age range of the hair samples Holmes et al examined. The NHANES results, however, were different:
Children's hair mercury levels: 0.22 ppm (+/- 0.04 ppm)
This puts the Holmes et al conclusions in a different light, doesn't it? The autistic children in the Holmes et al study had over twice the mean hair mercury level of the NHANES group (of 838 children) and the Holmes et al controls had hair mercury levels of over sixteen times the NHANES level.
What are they feeding those kids?
Well, the only conclusion that you can draw from that data is that the Holmes et al study is garbage. My suspicion is that their laboratory - Doctor's Data - is the cause of the outrageously high levels of mercury found in the children - especially the control children.
So, I hope that this stake through the heart will help this abysmal study finally rest in the obscurity that it so richly deserves.
I doubt it, though - the undead always rise again.