Thursday, January 03, 2013

Caution

Thomas Midgley Jr. is well known for having "more impact on the atmosphere than any other single organism in Earth's history".  Midgley's team was responsible for CFC refrigerants, and the introduction of tetraethyl lead as an antiknock agent in gasoline.  The CFCs have had both good and bad effects, the identification of the bad ones, ozone depletion, and the calculus is irrelevant at this point with the Montreal Protocols and the availability of adequate substitutes.  Tetraethyl lead is another story and a report in Mother Jones today provides a useful platform from which to view the introduction of GMO technology.

The Weasel has posed seven questions, but even he admits that there are two core ones

4: Can we really be sure that GM crops are safe — for our fellow creatures in the environment at large; or for consumers – whether livestock or people?
5: Taken all in all, do the advantages of GM really outweigh the perceived disadvantages and the conceivable risks?
which in the context of an anti-GMO web site he answers as
These are really one question, and are the heart of the matter: are GMO’s safe? The campaign’s answer is clear enough though:
All of the philosophy of science over the past 80 years or so (at least since Kurt Goedel and Karl Popper) has been telling us that science does not, and cannot, deal in certainties. In short, even if GM does produce some successes, it cannot justify the confidence that so many of its advocates display. Their confidence suggests that they do not appreciate the limits of science itself – which is itself rather worrying.
Yup, that’s right. Science doesn’t deal in certainties. Therefore you can’t be certain that GMO’s are safe. Therefore you cannot really quantify the “conceivable risks”. And therefore its all too dangerous to bother with.
This is, I think, fundamentally their answer. And if they just said that, well, I think I’d disagree. But I could accept they were honest. But wrapping this core up in spun-sugar propaganda isn’t honest.
 Eli's POV starts pretty much with his post on GMO's and Brian's post on politics and science and is not so far from Wm's, but the new information on lead's effects on the brains, especially of children, should make the three of us pause and be extra cautious.

It has been known for a long time that children exposed to lead are have lower IQs, but research has also shown that they are more aggressive.  Epidemiological studies carried out in the last twenty years have shown a clear relationship between violent crime and lead exposure.  This has lead to a number of investigations to identify the (or a) mechanism for this link.
One set of scans found that lead exposure is linked to production of the brain's white matter—primarily a substance called myelin, which forms an insulating sheath around the connections between neurons. Lead exposure degrades both the formation and structure of myelin, and when this happens, says Kim Dietrich, one of the leaders of the imaging studies, "neurons are not communicating effectively." Put simply, the network connections within the brain become both slower and less coordinated.
A second study found that high exposure to lead during childhood was linked to a permanent loss of gray matter in the prefrontal cortex—a part of the brain associated with aggression control as well as what psychologists call "executive functions": emotional regulation, impulse control, attention, verbal reasoning, and mental flexibility. One way to understand this, says Kim Cecil, another member of the Cincinnati team, is that lead affects precisely the areas of the brain "that make us most human."
So lead is a double whammy: It impairs specific parts of the brain responsible for executive functions and it impairs the communication channels between these parts of the brain. For children like the ones in the Cincinnati study, who were mostly inner-city kids with plenty of strikes against them already, lead exposure was, in Cecil's words, an "additional kick in the gut." And one more thing: Although both sexes are affected by lead, the neurological impact turns out to be greater among boys than girls.
Other recent studies link even minuscule blood lead levels with attention deficit/hyperactivity disorder. Even at concentrations well below those usually considered safe—levels still common today—lead increases the odds of kids developing ADHD.
In other words, as Reyes summarized the evidence in her paper, even moderately high levels of lead exposure are associated with aggressivity, impulsivity, ADHD, and lower IQ. And right there, you've practically defined the profile of a violent young offender.


And why was tetraethyl lead removed from gasoline?  Not because of it's effect on the brains of kids, but because it poisoned the catalytic converters introduced in the 1970s to reduce air pollution under the Clean Air Act in the US but even at that time there was evidence of the bad effects of lead on kids.  The usual suspects opposed both on the usual grounds.  Freeeeedom, costs money, don wanna.  Eli is old, not because of age but from listening to that crap.

Perhaps yet another reason to be cautious when eating one's breakfast?


5 comments:

badger badger badger said...

C'mon, it's not as if everybody knew that the chemical stability of PCBs and CFCs made them mostly harmless, at least until after the horses had escaped and bred their own feral herd.

badger badger badger said...

PS - A prof I TAed for suggested that, considering Midgley's involvement with lead and Freon, and the means of his untimely death, there should be an effect named after him.

John said...

So "gas lead" is down 90% from its peak but violent crimes are down 40%. Assuming the correct physiological connection, is the lead from coal burning making up the difference?

Also studied for decades have been the negative effects of poor general nutrition (devoid of toxicity issues) on pre- and postnatal developing human brains. Note that the affluent USofA does not escape the personal and societal effects of this physiological mental debilitation caused by shortage of essential nutrients at critical times in development. (How is that Planned Parenthood, WIC, etc. funding faring in the "family values" congress?)

(This is not, in any way, to be taken as support of the false promise of GMOs.)


John Puma

William Connolley said...

I added an update to talk about the "caution" point.

Anonymous said...

The real problem is that some "issues" (including something as "simple" as food allergies) may be extremely difficult to identify as a potential problem and even more difficult to "prove" (which is why a statement like "it's not like no one has tried to prove the dangers of GMOs" may not be particularly meaningful)

In many cases, the latter can only be done through epidemiological studies involving large numbers of people (trying to account for all the other possibly confounding factors).

No small endeavor.

And needless to say, actually relying on such studies to show harm is a very bad way to approach public safety issues,not least of all because there is often a lot of uncertainty associated with them (and hence room for denial of the results on the part of the GMO companies).

~@:>