No. You Aren't Eating a Credit Card Per Week.

I will admit that I tend to tune out claims from certain quarters to the effect of Something you've been doing for decades is an imminent danger to your health!

Nevertheless, I am aware of at least a dull drumbeat about microplastics and their potential to cause biological harm. I see the subject as one worthy of further study, but not as one worthy of such measures as banning single-use plastics, a favorite cause of many leftists.

Plastic -- and individual freedom for that matter -- are so valuable that any such ban would require extraordinary, conclusive evidence as to the harm of plastic that, for example, its careless use would pose a negligent or reckless threat to other individuals. (And even then, banning it might still be the wrong anwer.)

Ridiculous claims about the amount of plastic we allegedly take in from our environment or the harm that it causes do not foster a careful consideration of the scientific facts or of what (if anything) to do about them.

Faye Flam debunked two such ridiculous claims about microplastics in a piece titled, "The Real Microplastics Problem Isn't in Your Brain."

My favorite was the way-too-easy-to-remember canard to the effect that we're eating the equivalent of a credit card's worth of plastic every week:

Before the plastic spoon image, there was another alarming statistic: that the average person ingests enough plastic each week to make up a credit card. That claim was based on a 2019 study that used several models to estimate that the average person consumes either a tenth of a gram, three-tenths of a gram, or 5 grams (the credit card amount) per week.

[Chemist Mark] Jones noted that other scientists questioned the assumptions in that model, and a couple of studies found that the 5-gram figure was about a factor of a million too high, meaning it would take roughly 23,000 years to consume the amount of plastic in a credit card. Nevertheless, the credit card estimate continues to be propagated in popular media, policy circles and other studies. [bold added]

I like to imagine that some of these other scientists started off from the same thought I did when I first heard that: "I think I'd notice if I ate that much plastic."

Joking aside, Flam asks the same question that too many fail to ask in similar circumstances:

Is it OK for scientists, science journals and journalists to be less rigorous or critical of extraordinary results if they raise awareness of serious problems or otherwise contribute to the greater good?

Flam doesn't directly answer, but she does allude to a cautionary real-life tale:

Mark Jones, a retired chemist who has independently studied microplastics, drew my attention to the Nature follow-up, which the journal did not publicize as heavily as it had promoted the initial findings with a splashy press release. Jones said he's deeply concerned about scientists and journals failing to maintain high standards of evidence. He is worried about eroding public trust, as evidenced by the rising resistance to essential vaccines. [bold added]

Good. Too many scientists and public figures whose advocacy depends on science have been happy to sow panic rather than appeal to reason. It is good to see that some are beginning to understand the value of credibility.

The public may not be as scientifically literate as we would like, but that does not mean they are stupid -- or that they will not notice they are being treated that way, forever.

-- CAV