Archive for May 5th, 2008

Mercury emissions from coal-burning power plants and autism: Is there a correlation?

ResearchBlogging.orgOn April 30, outside the courthouse in Dallas, a press conference/rally was held. This particular rally was in response to a new study published by a group led by Dr. Raymond F. Palmer in the Department of Family and Community Medicine at the University of Texas Health Science Center in San Antonio, whose conclusion was that autism prevalence correlates strongly with proximity to mercury-emitting coal-burning power plants and other industrial sources of airborne mercury, the implication being that such sources of mercury may be causal or contributory to the development of autism. Unfortunately, the rally was reported by the media as though this study were slam dunk evidence that mercury environmental mercury is a definite contributor to the development of autism. For example, there is some video (also here) from local news sources of the rally, in the first of which it is stated as fact that mercury caused autism in the child featured in the story and in the second of which a mother who thinks that mercury causes autism is quoted credulously. This study has had much less play in the national news, but antivaccination activists, such as the ones at the Age of Autism website, a site whose main theme is that either mercury in the thimerosal preservative that used to be in childhood vaccines before 2002 or vaccines themselves cause autism, both promoted the rally and posted a glowing and credulous take on the study, as did “alternative medicine” and antivaccinationist website

My first thought upon reading of this is that it is yet more vindication of the science showing that the claim that mercury in thimerosal-containing vaccines is a failed hypothesis. After all, as I have predicted time and time again, as the scientific and epidemiological evidence continued to mount that thimerosal is just plain not associated with autism or autism spectrum disorders, even the most diehard adherents to this belief are starting to realize that they were backing a losing horse, especially since thimerosal was removed from all childhood vaccines other than the flu vaccine in 2001, leaving only trace amounts from the manufacturing process and there is no sign that autism prevalence is falling. That’s why lately, their effort has shifted from primarily demonizing mercury to blaming other “toxins” in vaccines, even to the point that their efforts to demonize some ingredient–any ingredient–in vaccines often reaches ridiculous levels of blatant silliness, such as touting sucrose as one of those “toxins.” Indeed, I was puzzled. If environmental mercury is the new cause of autism, then the rationale antivaccinationists use to demonize vaccines and portray their children as “vaccine-damaged” is much less potent. Why on earth would they tout this study, which, even if a good study (and it’s not), would weaken their arguments against vaccines immeasurably and take power away from their whole new propaganda slogan “Green Our Vaccines”? The only reason I could think of is that perhaps they somehow think that if mercury in the environment can be linked to autism that maybe–just maybe–they can convince people that they were right about mercury in vaccines all along. Indeed, this seems to be the sort of tack that David Kirby took a year ago when he started arguing that mercury emissions from coal-burning power plants in China (which do reach California), coupled with mercury emission from crematoria in which cadavers with mercury fillings were burned, were contributing to the continued increase in the autism caseload in California despite the elimination of thimerosal in 2001.

But what does the study say itself? Is it good evidence that airborne mercury from coal-fueled power plants is an important contributor to the development of autism? I will argue no, because the study’s flaws are so innumerable that it is well nigh uninterpretable. For simplicity’s sake, to summarize its findings, I’ll quote a Science Daily press release about it:

Posted in: Neuroscience/Mental Health, Public Health, Science and the Media, Vaccines

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