Letting those leaves pile up? New research shows leaf litter contains persistent free radicals

Ran into this article this morning and figured y'all would have lots of thoughts on it.
https://www.sc.edu/study/colleges_schools/public_health/about/news/2023/leaves_bpfr_vejerano.php#:~:text=%E2%80%9CWe%20found%20that%20both%20coniferous,impacts%20when%20inhaled%20or%20ingested.%E2%80%9D

Interesting study. When I look at the numbers, though, it seems to me that this is sort of the natural baseline of the biosphere under which conditions humans have evolved. Rather like natural background radiation. It's the concentrated man-made sources that pose a much greater hazard to health.

A couple of interesting quotes from the paper:

In the extant literature, we found reports of long-lived organic free radicals in other plant structures formed at certain conditions: in the woody tissue of a sycamore tree when infected by a fungus, (13) in coffee beans when roasted, (14,15) in seeds and pollen during artificial aging (16) and dehydration, (17) and in wheat leaf tissue when exposed to high ozone levels.

... The corrected (see Materials and Methods) calculated concentration was ∼1015–1016, which is 100× less than the [EPFR] in ambient PM2.5. The [PFR] in leaves was orders of magnitude lower than in other matrices such as those in PM2.5 and tobacco smoke (∼1016–1018 spins/g), (4−6) biochar (∼1018 spins/g), (20,21) wildfire charcoal (∼1019–1020 spins/g), (22) and PM2.5 from extreme haze event (∼1020 spins/g). (23) Also, the [PFR] values from all samples stored as dried powder for 1 year remained nearly the same.

Huh? They're saying that leaf litter is bad for the environment? So, something is obviously fishy here. Leaves have been "littering" forest floors since the carboniferous, or upward of 300 million years. During this time, these persistent free radicals have been a part of the environment. Given how large a part of the Earth has been covered in forest during most of that time, the substances must have been present more or less everywhere (on land at least) for much of that time. Basically everything alive on land today, including us, must have long since evolved to cope with their presence. Besides, what's the alternative to "piling leaves up"? Collect them all and incinerate them? A plain old burn pile wouldn't do it, either, since they list forest fires as a source of persistent free radicals...

Sorry for saying basically the same thing as you, Douglas. You posted while I was writing.

 leaf litter is an unaccounted source of persistent free radicals that, if toxic, may have negative health impacts when inhaled or ingested.”

"If toxic"-Sounds like more research needs to be done before burning our compost piles.

This is an interesting look and findings.

I found the study at this link and confirmed the author. - Link

A quote that we haven't touched on here but I think is equally as important is "BPFRs are contained in leaves and do not readily pose health risks, even if they exert similar adverse effects similar to EPFRs. However, the ultimate disintegration of leaf litter, the leaching of water-soluble BPFRs, and their adherence to soil particles can disperse them, thus creating potential exposure from them."

We don't have the worry about leaves. We have to worry about airborne soil potentially!

Keep something planted, keep a root in it!