Factual error: When Ian throws the unconscious Chloe over the edge of the dam we see her falling down as Clark falls with her. However, Chloe's body position is unnatural for someone who is falling while unconscious. Her head/body is arched backwards when air resistance should have forced her body to become level/straight.
Factual error: When Palmer is looking at the phone log, the wrong area codes are shown. Most of the list consist of the city of Topeka, with Wichita and Kansas City also seen, with a "206" area code. "206" serves the Seattle Washington area. The other area code seen is "620", which is a Kansas area code, but Topeka is in the "785" area code.
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