"Engine bearings can have copper in the alloy - usually less than 10 percent - but even if a bearing failed, that copper would remain "locked" in the alloy."

This may be the case with Volvo bearings (though I kind of doubt it) but it is far from universal. Almost all semi-modern engine bearings are bi(or more)-metallic with more than one layer. Per Rock Auto, Volvo engine bearings:

"Steel backed Bronze" for connecting rods
"Steel back - Aluminum" for crank mains

The first will contain an absolute minimum of about 55% copper and likely more that 70%. Bronze looks a whole lot like copper in the oil pan.

The latter may still have an "emergency" wear layer of bronze/high-copper alloy that is under the aluminum alloy that protects the crank from scoring should the primary bearing surface be severely scored...you know catastrophic loss of oil pressure, oil light comes on and attentive person rapidly switches off motor. As bottom end bearings are not really bearings at all in the traditional sense (the thin, uniform film of oil is the friction surface), that is about all that emergency layer is good for.

I have been hanging out WAY to much with a reliability engineer for a large diesel engine manufacturer. We have also seen a lot of "copper" in our race motors.