I got the termites from under rotting logs on our property, we never use insecticides or even fertilizers. We didn't cut down all our trees and plant non native species of plants like just about everyone else around here does, not even a lawn. So we don't have harmful runoff. We live on top of a pretty big hill so we don't get other peoples runoff either.
The nutritional value of termites is supposed to be pretty high and they are soft bodied so good for the babies.