Rust is just iron oxide, which in small quantities is a relatively benign substance. And probably there's more rust coming from old farming equipment than from

Rust is just iron oxide, which in small quantities is a relatively benign substance. And probably there's more rust coming from old farming equipment than from the (likely high quality, because they are built for expensive solar panels) steel structures here. The solar cells themselve are mostly made out of silicon, which also isn't a dangerous substance. I don't think this is an issue.