Hacker News Reader

Comment by ttyprintk | Hacker News Reader

California ag started late enough to avoid the concentrations of anthropogenic arsenic found in the Southeast US. Lead arsenate and calcium arsenate were promoted at the time of the Dust Bowl, which didn't affect CA. as much as the midwest. Places with a heritage of cotton used arsenic for even longer. Anthropogenic arsenic is inorganic. It does not decompose, so it bioaccumulates in plants. Some varieties can be bred for arsenic resistance. Some plants collect more arsenic than others.

View on HN

What's the viability of breeding plants to concentrate as much arsenic as possible, and then spending several growing seasons extracting it from fields, collecting the plants, and disposing of them?

I wondered the same. A quick Google turned up the fact, "Oh, yeah, that's been investigated and there ARE options."

Chinese brake fern (Pteris vittata) seems to be a candidate: https://www.newsweek.com/plant-arsenic-chemical-highly-toxic...

Plants as Useful Vectors to Reduce Environmental Toxic Arsenic Contenthttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC3913097/

I do have to wonder if we would find ourselves inviting invasive species with such an exercise. But on the other hand, the goal is to "grow'em, burn'em, and carefully dispose of the ash" so maybe that concern is manageable.

Fungus have been looked as one option for this. They are excellent bioaccumulators.

Or perhaps genetically modified fungus that emits a signature colorant proportional to its uptake of a contaminant. This would be a cheap way to screen a large area for levels of contamination.

California irrigation faces its own problems: https://psmag.com/environment/cleaning-up-californias-three-...

Both selenium and arsenic are considered trace elements. Selenium much more so; most of the world's diet is selenium-poor. But selenium supplements are useful in counteractive arsenic poisoning: https://www.ncbi.nlm.nih.gov/pubmed/23800687

I remember someone was trying to breed a species of rice to not bioaccumulate arsenic, specifically to plant in former cotton fields.

Wait, people were promoting arsenic?

Arsenic trioxide was widely used as a herbicide. A typical application would be something like 1 pound/1000 sq feet. ( 50kg/hectare for the rest of planet earth).

So dosing a field will take about as big a sack as you can carry and 250mg will kill you.

Extra fun fact: I got the application rate numbers from an article about controlling weeds on golf courses.

When people have a feeling about herbicides being dangerous… this is the kind of herbicide that caused it.

Extra bonus fun fact: My father's grandmother used to make up a mixture of arsenic trioxide and mercury to paint around the windows to keep bugs out of the house.

Arsenic was used for damn near everything from agriculture to manufacturing until about 100 years ago. It's a very effective pesticide (it kills everything!) and there weren't a whole lot of other options back then that actually worked.

https://www.chelseagreen.com/2009/the-tangled-history-of-ars...

Copper arsenate was banned in pressure treated lumber in the US effective January 2004.

(edit: I had thought this was in WA only, but wikipedia says national)

Lead arsenate was sprayed all over apples. Up until the 70s in some places.

We're really smart apes, we are.

According to wiki

> Alternatives [to lead arsenate] were found to be less effective or more toxic to plants and animals, until 1947 when DDT was found.

Pretty interesting huh!

Don't forget the lovely green wallpaper that was arsenic based.

Same people who sold you cocaine.

Better soak all that rice coming out of Arkansas.

Reply on news.ycombinator.com