Factual error: When Clark is on the roof, and Lionel calls him over to walk to his car with him, in the background as they walk, you can see a building which has the logo of a Canadian bank. Although set in Smallville and Metropolis, Smallville is filmed in Vancouver.
Factual error: Chloe wants to access the security camera files on the Luthor mansion server to see what happened to Lex. She can't crack the password, so she says she'll just download the entire hard drive. She pulls out a thumb drive and proceeds to do so. Two big technical problems here. Firstly, if she can't log in, she can't access anything on the server. And Secondly, the entire hard drive for a server (which is huge) containing video files (which are huge) will not fit on any thumb drive.
Factual error: Lana is trying to find out what Lex is up to. She gets a hold of his briefcase and takes it to the mansion where she shoots the locks off the case. When she does the case jumps a little bit but this is far less than it should. She is shooting at it from less than a foot away. The force of the bullet should have sent that case sliding across the desk at that range. (00:15:35)
Factual error: The last scene is said to be set in "Iguazú Falls - Patagonia, Argentina." Iguazú Falls are nowhere near Patagonia. (00:40:00)
Answer: The kryptonite only creates mutations when it reacts with the environment and an individual. Remember, the FDA and several environmental groups did check out Smallville after the meteor shower, but found no danger in the rocks. Obviously they're not always emitting mutating rays, or all the flora and fauna of the surrounding area would be horribly mutated.
Phoenix