Factual error: In the 5th season episode "Lexmas," Chloe says she needs Clark to deliver the Daily Planet's Toys For Tots contribution because of a Teamsters' Strike. However, the Toys For Tots program is run by the United States Marine Corps Reserve, and collection and distribution is handled by Marines and Reserves. The Teamsters have nothing to do with it.
Continuity mistake: As Chloe is trying to get Clark to help her deliver presents Clark says "Chloe, you didn't have to go there." Right before he says this the two of them start rounding the corner to go down the next hallway. As he is saying the line they are back in the first hallway and start rounding the corner again.
Plot hole: Clark is delivering presents for Chloe. In the overhead shots looking down on Metropolis he super speeds from building to building and he only spends like one second in each building before going to the next one. This doesn't match what is shown while we see him leave presents by the various trees inside the apartments. In those interior shots he spends 5-10 seconds in each room. The overhead shots are not sped up. Not only do these times not match up but he would also be slowed down to open the doors or he would constantly be breaking them down.
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