"Keys contain lead." ..WTF?

[Machine_Elf]

@Yllaria

When Caltrans buys additional land to widen highways, the soil near the highway must first be tested for lead contamination from car exhaust. It’s part of the environmental clearance before the purchase can be completed.

I’d bet at least some of the contamination is due to decades of lead wheel-balancing weights falling off of moving cars. Either way, out of curiosity, how often do these tests reveal problematic concentrations of lead in the roadside soil?

@jz78817

We phased out leaded gas decades ago.

Not completely. Most piston-engined aircraft still burn 100-octane, low-lead (100LL) “avgas”.

Avgas

The piston engines on general-aviation aircraft (not the gas-turbine engines used on turboprop or jet aircraft) need high-octane fuel to get the best power-to-weight ratio they possibly can. They need an octane booster to do this, and tetraethyl lead has been the go-to solution for a century. That’s likely to change very soon:

https://www.epa.gov/newsreleases/epa-determines-lead-emissions-aircraft-engines-cause-or-contribute-air-pollution

[Yllaria]

@Machine_Elf

Either way, out of curiosity, how often do these tests reveal problematic concentrations of lead in the roadside soil?

I don’t work for Caltrans, so I don’t really know. I only know about the tests because of a joint project where the city did the right of way (ROW) acquisition. Years after the joint work contract was signed, when the ROW parcels were being transferred to Caltrans, they tried to make us do new environmental documents because, among other things, the lead testing had been added.

Fortunately the contract specified that we had to meet ROW requirements as documented in 2001, and that was already done. So they did the tests themselves.

[MikeF]

@Tim_T-Bonham.net

you probably absorb more lead by breathing in the exhaust fumes from traffic on your commute to & from work.

Or eating dark chocolate

"CR tested a mix of brands, including smaller ones, such as Alter Eco and Mast, and more familiar ones, like Dove and Ghirardelli.

For 23 of the bars, eating just an ounce a day would put an adult over a level that public health authorities and CR’s experts say may be harmful for at least one of those heavy metals. Five of the bars were above those levels for both cadmium and lead. Read more about [how CR tested dark chocolate] "(https://article.images.consumerreports.org/image/upload/v1672933163/prod/content/dam/CRO-Images-2022/Special%20Projects/Consumer_Reports_Test_Methodology_for_Heavy_Metals_in_Chocolate_Bars_-_January_2023.pdf)