I don't think you would want any toxic metals in fuel given the risk of sending it into the air. There are probably real industrial uses, though, like reagents for labs.

AIUI you grow the plants, then process them to get the metals. Then you have plant matter with 'no' metals ... so using that to make bio-diesel seems possible? Depending on the details it might be possible to use the burning of the plants to extract the metals - similar effect (in that you get an energy crop and mineral extraction in one). You raise a valid concern though, thank you.

It would be cool to be able to get the diesel and the metal. The plants have stored calories in some form. There is a way to get energy from them.