He has collected no microorganisms in captivity. He has been kept by himself for his whole entire life. I don't see why there would be a problem with releasing him. It's perfectly OK to release a reptile when kept in captivity for a month. I know this is a huge difference in time, but again, I do not believe he has collected any microorganisms in captivity. Look, I have red-eared sliders inroduced in my area...how do you think they got there!?!?! Obviously from some irresponsible yet meaningful owners. I do not notice any effects of 'microorganisms' on the endemic painteds, redbellies, and snappers...