So obviously this all isn’t very ideal but they actually made at least two mistakes here. That pipe is not rated for being outside and also Romex isn’t allowed to be used in wet areas such as underground. Only something like UF cable would be allowed to be ran buried like this.

There’s two things that you can do here, the right way and easy way. The right way would be to rip the whole wire out and run it properly. The easier way would be to kill the outlet at the breaker, disconnect the wire from the outlet and to carefully remove the pipe and replace with a PVC pipe that won’t rust. Get one from the electrical aisle because those won’t degrade in the sun.