>A common error, when judging the effects of radioactivity or the toxicity of some substance, is to assume a linear response model without threshold (that is, without a dose rate below which there is no ill effect). Presumably there is no threshold effect for cumulative poisons like heavy metal ions (mercury, lead), which are eliminated only very slowly if at all. But for virtually every organic substance (such as saccharin or cyclamates), the existence of a finite metabolic rate means that there must exist a finite threshold dose rate, below which the substance is decomposed, eliminated, or chemically altered so rapidly that it has no ill effects. If this were not true, the human race could never have survived to the present time, in view of all the things we have been eating.
>Indeed, every mouthful of food you and I have ever taken contained many billions of kinds of complex molecules whose structure and physiological effects have never been determined—and many millions of which would be toxic or fatal in large doses. We cannot doubt that we are daily ingesting thousands of substances that are far more dangerous than saccharin—but in amounts that are safe, because they are far below the various thresholds of toxicity. But at present there is hardly any substance except some common drugs, for which we actually know the threshold.
The most dangerous substances fall into a few categories. Things like insecticides (which is what this thread is about) are designed to kill animals. Insects, but still, their physiology is close enough to humans. And things like heavy metals and radioactive substances. Which our ancestors weren't really exposed to.
The problem is people are designed to get cancer, or alternatively we are very good at pushing cancer off long enough not to be important but no longer than that. So, the odds of cancer by 90 are very high, and simply shifting a few years early may take a relatively tiny change.
In other words models about cancer risks based on 18 year olds don't extrapolate well to 60 year olds.
Maybe if you kept tons of test results of when I was normal, you could try to compare, but in addition to the problem that most people don't take tests when they don't notice issues (and even when they do, the medical profession just seems to love to destroy files after a number of years: it just feels criminal to destroy data like that on someone's medical history), the test subject is also getting older and you expect them to not function as well :/.
Even if you know something is failing, often medical science just doesn't care: over a decade ago I was getting hearing tests done occasionally as I could tell I was losing the hearing in my right year, but I had hearing that was so good (better than most people even for being in my early 20s, when everyone still has good hearing... and so usually aren't taking hearing tests) that the doctors would explain I'd topped out their charts, had "excellent hearing", and they couldn't even know if something was wrong. Well: I definitely have extremely worse hearing in my right ear now :/.
It wouldn't surprise me if the exact opposite were true: that medical science often estimates things assuming there are "thresholds", when quite possibly almost nothing is subject to a threshold effect while often being cumulative; the issue being just that the response curve is sufficiently sloped, and is further skewed by tests based on results instead of on internal state, that it looks like there are thresholds, and so we underestimate essentially everything dangerous.
We are actually all supposed to be 7 feet tall and full of muscles, we just don't know it because every last one of us has been stunted by poor diet and what not.
That's my story and I'm sticking to it.
But this is funny:
> And things like heavy metals and radioactive substances. Which our ancestors weren't really exposed to.
Please excuse the Wikipedia quote. The numbers are right, and it's written well enough:
> 40K occurs in natural potassium (and thus in some commercial salt substitutes) in sufficient quantity that large bags of those substitutes can be used as a radioactive source for classroom demonstrations. In healthy animals and people, 40K represents the largest source of radioactivity, greater even than 14C. In a human body of 70 kg mass, about 4,400 nuclei of 40K decay per second.[2]
K-40 is primarily a beta (electron) emitter.
There is some probability that a mutation will trigger an internal check in the cell to detect bad mutations, and the cell will commit suicide.
There is also some probability that the cell will die accidentally before the second mutation.
There is some probability that the immune system will detect something fishy and kill the cell just in case.
If the time between each mutation is bigger, then you have more time to get lucky and remove the cell while it has a single mutation, before it can accumulate more mutations and become dangerous.
So a lower dose will increase the time between mutations and make the case of two accumulative bad mutations less common. Then at small doses, the effect is not linear and perhaps below some threshold the ability of the body to detect problems will fix all the cases before you notice.
The problem is that it's very difficult to measure the effect of very low doses for a long time. (You have to test the drug in some animal that lives for a long time like elephants instead of mice.) (And it's difficult to get funding and graduate students for a 20 year experiment.)
So the "linear non threshold model" is slightly pessimistic, it err on the side of caution, but it's probably good enough and not too alarmist.
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Technical note: There are actually no cells with zero mutations. All cells have some mutations. Some have less, some have more. Some mutations are dangerous, most are innocuous, a few may be advantageous. But to simplify the discussion, I just ignored this and imagine that usually the cells have no mutations.
In a side note, Organophosphates replaced Organochlorides for a very similar reason. They have a much faster elimination rate, reducing the time that they stay in the food chain (and hopefully reducing the exposure of non-target species). Organochlorines, on the other hand, were very stable, which made them easily stored, but also caused biomagnification, where animals further up the food chain started concentrating it in their bodies as they ate smaller animals that had been exposed. This caused serious environmental effects, leading to the shift to the pesticides we use today.
- Consuming less food requires the body to use fat-reserves. Some of these might have been storing heavy metals. With a quick enough change in diet, these might pose a significant risk.
- Consuming less food might alter your gut microbiology. Disheveling this balance might create the risk of infection or even worse.
- Consuming less food (to be precise, less lipids), might alter, or even disable certain parts of the metabolism, often leading to deficiencies in supplies for the immune system, thus making us more vulnerable to 'poisons'.
I don't know which of the above hypotheses are correct, but I am sure they are just as (un)likely as yours is.
Is your point merely that everything is Schrödinger's chemical unless we study it? That is a stupid stance. This article is clearly associating a = b+c, ie: this chemical is causing bad things for your intestinal microbes which leads to diabetes, etc.
I feel like you are maliciously attempting to downplay the severeness of the studies' results by introducing the Schrödinger argument. I am calling the quote by ET Jaynes to be pointless and equating his example of radioactivity to the aforementioned water example.
With this equation in mind, are you trying to say that a small dose of our insecticides is good for us, but, we are abusing it? Do you have any grounds for this? Even E.T Jaynes implies there is no proof for this statement because of the lack of studies. Why would you downplay this?
More than that, he is saying there is a double standard for synthetic substances.We treat them with much more fear and caution than the natural chemicals we are exposed to all the time. Many common vegetables would not pass FDA requirements if they were "invented" today. They contain thousands of chemicals. Many of which have never been tested, and some of which are even known to be toxic. Like solanine.
The issue I am having with the comment is that this is a specific study on a specific set of chemicals that produced a specific outcome. We're not discussing chemicals in general, and yet you are making it seem like the results of this study should be ignored because chemicals can be good and bad.
To draw a comparison, it's like someone posted an article about high concentrations of asbestos leading to health problems, implying that maybe we shouldn't use it as an insulator. It's not implying that we shouldn't use insulators. It's simply implying that maybe we should reconsider the use of this specific insulator. Then you come in commenting nonsense about how insulators are a good thing, and that we need insulators. The issue is that nobody is arguing against you. You're right that insulators are a good thing and necessary. The problem is that takes away from the main point of the article, that we should reconsider the use of this specific item.
The grandparent comment I replied to is literally about fearing man made chemicals in general.
>To draw a comparison, it's like someone posted an article about high concentrations of asbestos leading to health problems, implying that maybe we shouldn't use it as an insulator. It's not implying that we shouldn't use insulators. It's simply implying that maybe we should reconsider the use of this specific insulator. Then you come in commenting nonsense about how insulators are a good thing, and that we need insulators.
It would be more like if someone posted an article about asbestos, and the top comment was about how they strongly distrust all man made materials.
It's reasonable to avoid risk by sticking with (e.g.) tried and true food sources, but I'd argue that the revealed preference is for a much larger amount of risk tolerance. The most ardent naturalist will gladly accept a new berry that none of their ancestors ever encountered simply on the basis that other people are eating it without ill effects. They do not demand generational studies on millions of people, and yet the same concerns you bring up for synthetic compounds absolutely apply. Nature is responsible for the overwhelming majority of the worst toxins we know of, but unknown natural compounds are accepted with a relatively modest amount of evidence for their safety. I think the double standard we apply to synthetics is absurd.
See also: radio waves. We can concentrate them to the point where they literally vaporize living tissue. This means we can make (and have made) absurdly good measurements of their toxicity and carcinogenic tendencies, yet my (techie!) friends still joke that their cell phones are giving them cancer.
However, "natural" is a reasonable heuristic for "something our bodies have had time to adapt for" and the introduction of synthetics has short-circuited the evolutionary feedback loop.
Heavy metals are probably a good example of this, perhaps in another million years there will be humans and animals that have excretive pathways for mercury.
My issue is that most of us live in a world of plenty and we do not need to incur many of the risks that we do through chemical exposure, especially as their use is typically to serve a business' needs rather than our own. Additionally, the opacity of the problem is also an issue because it is hard to make informed decisions about what we consume due to us being many levels detatched from the supply chain which produces that which we eat.
I've heard this often when it comes to GMO crops ("we need these to feed starving people"), but I'm not sure how much evidence there is for it. There was an New York Times investigation into GMO vs. non-GMO crop yields recently where they found no discernible difference between the two[1]. I've heard some criticism of the article, but most of the criticism I've seen comes from people who have decided ahead of time that GMO's are wonderful and any criticism of them is bad.
Also, from what I've seen the problems with food scarcity don't stem from low crop yields but rather from distribution. I don't think seeing it as a crop yield problem is the right way to approach it.
[1] https://www.nytimes.com/2016/10/30/business/gmo-promise-fall...
That article you linked was flawed on quite a few levels. It argued for example that France was able to reduce its levels of pesticides without using GMOs and used percentages to show the reduction, thereby arguing that GMOs are not necessary
But looking at absolute values, France had a far higher use of pesticides and insecticides and even after the reduction it is still higher than the US, although in the US herbicide use has gone up (primarily glyphosate, but that replaced other more toxic herbicides).
Greater crop yield means more efficient use of the land and resources. I agree we produce more than enough food but reducing yield is not the answer. Also we've barely scratched the surface in terms of using the potential of GE.
[1] http://weedcontrolfreaks.com/2016/10/the-tiresome-discussion...
Absolutely agree on this one. The world produces enough food (well, cereal grains) to feed everyone. However, I would still argue that increasing crop yields is incredibly important for the species as a whole. Better yields means lesser land required for cultivation. You basically reduce the environmental footprint of agriculture and I think this would be incredibly important e.g. in Africa where you either may not have a lot of Arable land OR might not want to cut down virgin forests just to feed your people.
Alfatoxin, a potent carcinogen, comes from a fungus that grows on peanuts.
This study compares those that have direct exposure to the organophosphates such as farmers and pesticide sellers in India to those with indirect exposure (eating the food and exposure to runoff) to see this diabetes correlation.
Granted, the exposure rate is much much higher than the average person's exposure to "chemicals", but over the course of a lifetime, similar mechanisms are surely in place.
When you consider factors like plastics leaching into drinks (and it goes without saying how ubiquitous plastic bottles are)and the accumulation of other chemicals through the food chain (think mercury concentrating up the chain into tuna), the exposure rate is probably much higher than we realise.
Another favourite was how cis-platin would crosslink DNA to prevent replication of cancer cells in your body.
I think you meant "DNA transcription".
Different harmless organic molecules that together work as sand in the engine.
https://en.wikipedia.org/wiki/Isotope
Not sure what biological processes are sensitive to that though.
https://www.omicsonline.org/open-access/biogenic-chemical-el...
That there is a growing market for "clean" produce is an indication that there is a growing awareness and appetite for change
Most people who die from smoking don't die from cancer. You could easily reduce the risk of lung cancer from cigarettes, but that would place an enormous burden on the healthcare system, because then smokers would just die from more expensive conditions like emphysema.
If government required tobacco companies to limit the amount of radiation in their productions, cigarette taxes would need to go up to compensate. The real solution is just making the sales of cigarettes illegal, and then forcing people to buy loose tobacco and roll their own if they want to smoke.
I worry that people who vape are in for a terrible surprise a few decades after they start vaping.
If only.
The idea that this is some sort of backdoor effort to criminalize tobacco or smoking is completely misguided.
The human physiology is unfathomably complex and the advent of synthetic chemistry has meant that we are now exposed to new molecules which have arisen at a rate tens, hundreds of thousands of years too early for our bodies to evolve to accommodate for them. Our exposure to these chemicals is also incredibly opaque: even eating "clean" by eating fruit and veg exposes us to a multitude of chemicals that come along the pipeline including fertilisers, pesticides and preservatives.
Nature is exquisitely sensitive to chemistry - I recall reading that natural systems have evolved to exploit and dispatch behaviour based on the isotopic composition of carbon-based molecules: naturally synthesised molecules also have a different isotopic profile to artificially synthesised molecules. For the record, Carbon-13 represents ~1% of the natural isotopic abundance.
If something as granular as the isotopic distribution of elements is important to physiological systems, how can we be so complacent as to constantly pile chemicals into every aspect of our lives?
Businesses will wantonly and irresponsibly use any method to increase their bottom lines and it falls to regulators to moderate this behaviour. As an example, I recall McDonald's doping their chip oil with a known toxic organic chemical to lower the rate of thermal decomposition of their oil. This is something they could as easily avoid by replacing their oil more often, but this is costly: they instead defer this cost onto our health by exposing us to unnecessarily dangerous chemicals.
In my opinion the FDA's (or indeed global regulators') thresholds for the use of chemicals is not stringent enough - humans are living longer, how do we know that prolonged exposure to any of these individual chemicals (let alone the cocktail of all of them) over a 50-100 year period are worth the risk?
For another anecdote of irresponsible chemical usage - the onset of lung cancer through smoking underwent a stepwise increase after the tobacco industry started using phosphate fertilisers to increase their crop yield: a side effect of the fertilisers was to enrich the soil in radium which would decay down to Pollonium-210, an alpha source of Russian-assassination fame. Studies have been done on characterising the sievert profile of tobacco leaves, highlighting the risk of this but no action on the tobacco industry has been taken to mitigate this.