Would you rather? … a different way to look at chemical safety
July 18th, 2011
Note: Today is the first day of our (CJ, Leigh, Paul and me) most recent blogging roundtable. We all got started down this road when Paul said (over email), “Hey, I wanna talk about what people are getting wrong in their energy science arguments. I had tons of fun doing our last roundtable. Lets do another one!” We quickly decided that Paul was right (isn’t he always right??), and that we all were excited to do another round table. A common theme of “what people think about chemists/chemicals/chemical industry and why these opinions grate on us as chemists” instantly propped up. But, we couldn’t just call our roundtable “Hey, You’re WRONG.” So, again, Paul saved us by coming up with the very punny CHEMisperceptions. And, with the whole #altchemicalfree kerfuffle amid the always present organic outrage, we thought it might be a good time to do something like this. We hope that you enjoy it. And we REALLY hope that there are countless conversations going on in the comments sections of our posts. That’s where the real fun is anyway!
A new student recently joined my lab. Although she hasn’t had a lot of chemistry experience, her enthusiasm and desire to learn have been stellar! I’ve started her off running a couple of reactions that use methanol as a solvent. In giving her a basic description of methanol, I said:
Methanol is kinda like ethanol, the alcohol that we drink. But, it’s much more flammable. And, it makes you go blind when you drink it. In fact, during prohibition, the bootleggers used to spike their liquor with wood alcohol (methanol). This compromised drink caused blindness and killed off quite a few people.
I proceeded to tell her:
We’re using it because it will dissolve both of the molecules we are reacting and it won’t get in the way of the reaction we’re trying to perform. And, methanol has a low boiling point … so we can remove it fairly easily from our product.
She took all this in stride and then said what any good scientist should say:
So, we’re going to be using this a lot. I should probably find out more about it.
And, this is true. Unfortunately the best way to learn about a chemical and its reactions is through experience. There is a great post over at The Curious Wavefunction on chemical intuition (something that I’m still hoping I’ll get one of these days). But, in lieu of telling her to go work with methanol for a year and get back to me with its properties, I proceded to point her to the MSDS (material safety data sheet) for methanol. The MSDS is the standard piece of information that chemists and medical first responders go to when they want to learn some basic features about a chemical. The MSDS will tell you if the chemical is a solid, liquid or gas at room temperature. It will tell you if it is flammable. And, importantly, the MSDS will tell you how toxic a chemical is. To describe the toxicity, MSDSs and other sources of information use the ubiquitous term “LD50″, which stands for “Lethal Dose 50%”. In english, what this means is that a specific dose will kill 50% of the animals it is fed to. For methanol administered orally to rats, the LD50 is 5600 mg/kg. (5600 mg will kill half of all rats weighing 1 kg. 11200 mg will kill half of all rats weighing 2 kg.)
These numbers are pretty basic. And they give us a vital bit of information. But, they really don’t give us (as chemists, consumers, watchdogs, and concerned citizens) any nuance on when/what levels certain amounts of chemicals start to noticeably affect us. For instance, what amount of methanol will make a person go blind? What amount of methanol will make a person feel woozy? What is the safe amount of methanol that I can be around through contact/inhalation/ingestion? Thankfully, methanol isn’t something that we have to worry about finding in our foodstuffs like we did in the 1920′s and 30′s. (For a great account of wood alcohol and bootlegging, read The Poisoner’s Handbook by Deborah Blum.)
There are many many other chemicals that we do and should worry about in our consumer products. Chemical Abstract Services, which runs a database of chronicling many of the molecules that chemists have worked with over the years currently contains over 60 million entries. That’s a lot of chemicals. Certainly no appreciable amount of these have had their LD50′s determined. How are we possibly to know which of these chemicals are dangerous?
Unfortunately, the best stance is to assume that all chemicals are dangerous until proven otherwise. That seems to be a recurring theme to many chemicals used by industry. The “chemical-scare-du-jur” comes to us in the form of BPA (Bisphenol-A). BPA is used in making many types of plastics. The products that have BPA in it are very durable and resistant to damage by heat. BPA is also very cheap. Because of these reasons BPA is found in an innumerable amount of consumer plastics. There is so much BPA out there that it can be found in human urine samples at levels where physicians expect it to effect thyroid function.
Unfortunately, these reports do nothing to dispel the notion that all industrial chemicals = bad and all natural chemicals = good. This notion is laughable. I’d certainly take a little BPA in my system over an equal amount of rattlesnake venom. That gets us to a larger point here: The dose makes the poison. All chemicals ARE dangerous at certain concentrations. Even water has a measured LD50. (The “toxicity” or ability of water to kill humans is best exemplified in the dihydrogen monoxide hoaxes that have run their way through the internet.)
Fortunately for people in the US, we have the FDA watching out for us, making regulations for what can and cannot be placed in the foods that we eat. Unfortunately, the safety of our food doesn’t seem to be garnering a very high priority right now.
It would certainly help if we all could have consequence-free experience telling us which chemicals are more dangerous than others. The LD50s are OK in that they are descriptive. I just don’t think that they are useful to very many people. I think that we need to come up with a new metric that everyone can relate to, something that most people will understand.
I propose that we communicate chemical safety as a game of sorts. We could use the template of “Would you rather” (for instance: Would you rather kiss a pig or walk through thistles in bare feet?) to describe the harmful effects of chemicals. Communicating risk in this manner would require that 1) the comparisons are standardized so that everyone can understand the effects of a chemical 2) the comparisons include both severity and long term exposure where needed and 3) everyone understands the comparison. (Oops. Did I already say that? Well, it’s important and deserves saying again).
For our description of the risks of chemicals, I propose that we compare all types of chemical exposure to taking a shot of whiskey. Comparing chemical exposure to whiskey has a couple of advantages. 1) Most of us understand the immediate effects of liquor on our systems. 2) We also understand what increased dosages of alcohol will do to us. And 3) The long term chronic effects of steady alcohol consumption have been pretty well studied. Some examples of the “would you rather” platform being used with chemical exposure are as follows, “I would rather take 15 shots of whiskey than 1 shot of methanol.” Or, “I would rather take a half-shot of whiskey every day for the rest of my life than be exposed to BPA at 1 ppm (part per million) in the foods that I eat for the rest of my life.” (Editor’s note: I’m not entirely sure if this statement is factual.) You can easily see how this would lead to some very interesting conversations about chemicals and chemical exposure.
Unfortunately this approach is not perfect. Different chemicals and different kinds of exposure lead to different physiological effects. And, ethanol use has varying effects in different users. But, I think that alcohol is the perfect chemical to base our tolerance to other chemicals off of. So perfect, indeed, that I believe if our public health officials start using these ideas instead of LD50s or other exposure data, we would see an immediate increase in how the public understood the risks of various chemicals.
So, my question to you, dear reader, is, “Would this work?” “Do you have any better ideas?” “What do you think would be the most EFFECTIVE way of discussing the relative risk between one chemical and another?” “How do we discuss threshold limits for chemical exposure?”
There are lots of issues to worry about here. I think that the “would you rather” approach would work quite nicely. In fact I’ve devised a little quiz that was at the start of this post (using cherry-picked information) to see how people respond to different chemical exposures. (For example: Would you rather drink 100mL of bleach or 100 molecules of palytoxin in 100mL of water?) Please try your hand at it if you haven’t done so already! There are no wrong answers. I’ll report back here on Friday with the results!
And, don’t forget to check out CJ’s post on what “chemists do at work” tomorrow.