The card slot looks perfectly normal. I can't see any obvious problem in there.
The camera is approx 2yrs old and has had intermittent use during that time. The environments you mention have never been experienced.The battery is functioning fully, as all the camera controls work normally when the card is removed.
One other point which may be relevant? The A/V Out port (opposite side of camera to card slot) appears slightly loose in the body of the camera.