PFCs, Ultrasound, and Autism

Robert Delaney is a geologist who does environmental cleanup in Michigan. While cleaning up an abandoned military base, he found remarkably high contamination by a chemical called PFOS. He had been wondering what causes autism. He came across a rodent study that found that the combination of PFOS and ultrasound was much more damaging to the nervous system than either alone. (See also this study.) He remembered that study when he read my posts about ultrasound and autism. He wrote to me:

You will know the chemical PFOS (perfluorooctane sulfunate) from spray-on fabric treatments that protect clothes from stains and water. I want to tell you about the possible connection between PFCs (perfluoroalkyl chemicals, especially long chain PFCs) and autism.  I learned that mice and rats contaminated with PFOS, a PFC, when exposed to ultrasound convulsed and died.  I was reminded of that finding when I read your blog about Caroline Rodger’s idea that prenatal ultrasound causes autism.  I have thought that PFCs were causing autism for some time. I wondered if lower levels of PFOS would cause some type of brain injury, short of convulsions and death, when the mice were exposed to ultrasound.

I work on cleaning up military sites and attend a lot of related conferences and meetings.  I am working on a focus group with the Association of State and Territorial Waste Managers Organization that is looking at emerging contaminants (contaminants that are not regulated or so recently regulated they are still a problem). Because of that, I was recently made aware of the PFCs because the military had identified these contaminants in firefighting foams.  I was doing a cleanup at the former Wurtsmith Air Force Base in Michigan.  I decided we should check for PFOS and PFOA at the site.  There were high levels of both PFOS and PFOA even though it was 20 years since the based had been used. When we checked groundwater, we found it in every well at every depth.  In my 25 years in the environmental business I have never seen anything like it.

I started researching the chemicals as it was apparent that I would have to deal with them.  I discovered that at least 98% of Americans have them in their blood. That isn’t surprising because they are in everyday products such as food wrappers and popcorn bags, shampoos, cleaning supplies, carpeting, furniture materials, clothing, and dental floss. They are used in firefighting foams, pesticides, automotive parts, computers, electronics, and lubricants.  They have ended up in our food supply and drinking water.

I had been researching the occurrence of autism for other reasons.  It had occurred to me that whatever was causing the dramatic rise in autism around much of the world, it had to be ubiquitous in the environment, of recent origin, with increasing use, and found  in at least the US, Canada, Europe, Japan and Australia where the autism rates were exploding.

PFCs fit these characteristics.  They are found around the world in mammals, birds, fish, shellfish, etc.  In fact, the Canadian government reported that the blood levels of PFCs in polar bear above the Arctic Circle were higher than the levels of any pesticides they had ever measured.

Research in the Great Lakes Region is showing high levels of PFOS in the lakes. In some places in the Lakes the contamination exceeds preliminary drinking water standards. Because these are huge bodies of water, to have so much contamination is amazing. High concentrations have been found in mink, fish, gull eggs, eagles, etc. around the Great Lakes. Fish and drinking water in Minnesota have been impacted over large areas. Europe has now banned PFCs for most applications.

What got me wondering about autism and PFCs was that in lab animals and in test tube experiments with human brain cells they are developmental neurotoxins. Many chemicals are neurotoxins, such as chlorinated pesticides and other chlorinated compounds (such as PCBs), organic mercury, and lead.  However, we in the western world have been aware of these facts and for the last thirty years have been reducing use and exposure to these chemicals.  But while we have been reducing our exposure to mercury, lead, and so on, neurologic diseases have been on the rise.  No one suspected PFCs were harmful to humans. Their use has continued to increase.

The half life of the chemicals in our body is around 5 years, so in 5 years, if you have not gotten any more exposure to PFCs, half of them would still be in your body.

There are a lot of reasons to think PFCs may cause autism.  Here are a few. First, the company that invented PFCs (3M) is located in Minnesota. There is widespread PFC contamination in Minnesota. As I was preparing a talk last week, I googled…”autism state rates.”  The first site to pop up listed Minnesota as having the highest levels of autism of any state. New Jersey has unusually high PFO contamination of drinking water; they also have a very high level of autism. The military, which has used a great deal of fire-fighting foam, has double the rate of autism of the general U.S. population.

In laboratory experiments PFCs influence brain wiring. The impact of PFCs in some mammals is sex-dependent with males being more affected; autism is 4 times more common in boys than in girls. PFCs are associated with repressed immune systems in animals which has been associated with autism as well. Deranged behavior/ADHD behavior has been reported in PFOS-exposed mice.  ADHD in children has been associated with prenatal exposure to PFCs.

Unfortunately, the EPA did not include PFCs in their list of chemicals that might be causing autism. My colleague and I have put together a web page if people want more information: http://www.autism-pfos.net/

Yes, why does Minnesota have such high autism rates? It is not an industrial state. It is not a rich state. Yet it is where PFCs were invented and manufactured in large amounts (e.g., ScotchGuard). I can’t think of a plausible alternative explanation. The lab results (ultrasound plus PFOS far more damaging than either alone) makes perfect sense: If there is a bad molecule in neural tissue, it is going to do a lot more damage if you start shaking it, which is what ultrasound does.

10 Responses to “PFCs, Ultrasound, and Autism”

  1. sabril Says:

    I did a google search for “autism rates by state” and found this chart:

    http://www.stellamarie.com/index.php/2010/06/24/autism-rates-per-state

    Just eyeballing it, it looks like there is a strong correlation between autism rates and percentage of votes for democratic candidates in recent presidential elections. Put another way, there are a lot of blue states at the top of the list and a lot of red states at the bottom.

    So my hypothesis is that there is something political at work. For example, perhaps liberal states are more aggressive about diagnosing autistic children and putting them in special education. Just from general observation of adults, it is clear that there are a good number of borderline autistic people.

    Is there a clear, objective definition for autism which is universally applied?

  2. Seth Roberts Says:

    Sabril, if you make a scatterplot of autism rates (log) vs percent vote for Obama (or some other measure of “percentage of votes for democratic candidates in recent presidential elections”) I would be happy to post it. Your idea doesn’t easily explain why autism is higher among military families than in the general public nor does it explain the huge changes over time. I think plausible explanations for autism must be able, above all, to explain the huge increase over time; there is no precedent for such a giant change being due to diagnostic vagueness.

  3. UncleLongHair Says:

    Correlation is not causation…

  4. dearieme Says:

    “there is no precedent for such a giant change being due to diagnostic vagueness”: except in psychiatry?

  5. Seth Roberts Says:

    “except in psychiatry”? I know of no psychiatric examples. The occurrence of depression has increased by a large factor over the last 100 years. This is accepted as real, in spite of diagnostic vagueness.

  6. sabril Says:

    I tried to post this before but it got swallowed.

    I don’t have the time and skills to create a scatter plot, but I did create a map:

    http://monarch.tamu.edu/~smrs/16162627.gif

    The blue states represent the 25 states with the highest levels of autism; red the lowest.

  7. Robert Delaney Says:

    In response to UncleLongHair, I totally agree that correlation and coincidence do not prove causation. For example, if one looks at a long list of facts concerning the assassination of President Lincoln and President Kennedy, one can find lots of correlations. All that proves is that if you look at enough random facts about any two events, you will find interesting coincidences. I am not claiming that there is difinitive proof that PFCs cause autism. In science, we view a phenomenon and then postulate about possible causes. We then determine ways to test our hypotheses. The “proof” of any hypothesis comes when we can use that hypothesis to make predictions and those predictions prove to be true. As for Sabri’s comment, there are many autism “clusters” that have nothing to do with political boundaries, but might be explained by different types of PFC exposure senarios . As Seth points out, the rise in autism rates over time must be explained.

    I appreciate Seth’s patience to explain things. For myself, I am just looking for a few highly qualified, careful and objective individuals that can tackle the difficult job of studing the toxocology of PFCs, and who can do the epidemiologic studies. I hope no one “knows” that PFCs cause autism because some geologist thinks so. I understand contaminant fate, transport and human exposure. I leave the real toxicology and epidemiology to the experts.

    Fortunately, I have already run across some experts since I wrote to Seth that are interested in the subject, and one epidemiologist who was actually beginning to look at the possible link between PFCs and Aspergers. A public debate at this time is folly without hard science. However, the stakes are incredibly high and we need to find the cause or causes of these diseases as fast as possible. Pointing in one possible direction of a cause is not the same as faking data as happened in the case of the vacination hypothesis.

    Sabril’s comment, although not taking into account multiple lines of evidence, is still useful as it points out the need for care with coorelations and allows me to explain why people should not jump to the conclusion that PFCs and ultrasound cause autism. Researchers that are qualified have to look at the data, determine if they think this might be an idea to examine, design the tests, and then communicate the results to other qualified scientists for them to test and examine. Unfortunately, that is a slow process while we are facing a very urgent problem.

  8. sabril Says:

    To follow up on my previous comment, the map could easily be an electoral map. (Ok, with a few exceptions like Texas and Illinois, but still.)

  9. sabril Says:

    Oh, and check out the map here:

    http://voices.washingtonpost.com/ezra-klein/2010/04/the_red_state_ripoff.html

    It allegedly divides the states up based on the flow of tax revenue and is very very similar to the autism map.

  10. Peter Andrews Says:

    “why does Minnesota have such high autism rates?”

    Perhaps because of its latitude and corresponding low average levels of vitamin D.

    ncbi autism vitamin d search