arsenate

Spraying lead arsenate as a pesticide on apples was a fairly common practice up until the 60s.

Yeah don't even start to read up on lead arsenate sprays in apple orchards through most of the 20th century.

Chromated copper arsenate, which is highly toxic, used to be used to make pressure treated wood.

On cotton fields lead arsenate was used as a pesticide to kill boll weevils.

Apple orchards in particular up until the 70s often used lead arsenate pesticide sprays.

There are certainly exceptions, for example many old orchards used lead arsenate as a pesticide, contaminating the soil with both lead and arsenic.

For around a hundred years until only several decades ago fruit trees, especially apple and pear trees, were sprayed with the insecticide lead arsenate (lead hydrogen arsenate, PbHAsO4) to protect against codling moth and such.

They used to literally spray lead-arsenate on apple orchards as a pesticide.

Lead arsenate was sprayed directly onto fruit (like apples) as an insecticide until the government revoked its authorization for use on food products in 1988.

Because calcium arsenate was used to kill the boll weevil.

I think treated pine sleepers in Australia are mostly CCA (copper chrome arsenate).

It's a timber treated with pesticide (chromated copper arsenate).

Do customers ask for a very well defined phenotype ("makes >1g/l/hr paclitaxel", "expresses gfp in >1ppm arsenate across a wide range of ph, osmolarity") or do they ask for more well defined things like stable lines expressing some gene?

Instead, my options are (at least for another year), purchase the less stringently regulated "hemp" products or the entirely unregulated stuff grown god knows where by god knows who with no recourse if it turns out they've been spraying their crop with leftover lead arsenate.

They stopped allowing arsenic (Chromated Copper Arsenate) in pressure treated lumber in 2003 in the US.

It was probably treated with Chromated Copper Arsenate, which is a carcinogen.