Continuity mistake: Clark and Martha show up at the barn. The interior rear view mirror is missing when looking out from inside the car, but it is there when looking in the car from outside.
Continuity mistake: When Clark looks at Phillipe's police report, there is a photo of Phillipe facing sideways. In the next shot the photo has changed, so that now he is facing forward. (02:21:10)
Continuity mistake: When the officer tries to disable the bomb, the read out displays 19 seconds. After he drops it, the display shows 29 seconds.
Continuity mistake: In the shot where Clark picks up Lex's cue stick, the balls on the table are spread out in an arch consisting of 4 balls. The shot switches to a low level shot looking at Lex and the balls at Lex's end, where the arch should be, are no longer forming an arch.
Continuity mistake: During the opening scene, behind Jesse you can see the vice principal walk up behind her and reach out as he's about to put his hand on her shoulder, yet the very next shot of Lana, in the background you can see he's just exiting a room.
Continuity mistake: As Alicia holds the kryptonite on Clark her hand turns between shots. While she says ".but you broke the rules first." there is a camera change. Before the change the frontal view of Alicia has her holding the kryptonite with the glowing part straight up. After the camera change she is now holding it so it points to her left.
Skinwalker - S2-E10
Continuity mistake: While he is being attacked by the wolf the foreman fires the flare gun with his arms spread, meaning that it would fly at an angle away from him. He then sees it arcing back from below toward him, impossible unless the flare changed direction and location in the air. (00:02:20)
Continuity mistake: At the beginning, when Seth picks up the barbell to beat Troy with, Troy is at the end of the locker room with the showers. As Pete and Clark show up, Troy is at the other end of the locker room.
Other mistake: Early in the episode, Clark uses his heat vision to blow up a police car. In the shot where we see the policewoman diving for cover, there is a front view of the car as it is exploding. The license plate on the front of the car IS a Metropolis plate, however, as the plate falls off, the white placard that auto companies and dealerships place in the license plate frames on new vehicles before they are registered and which are removed once plates are installed is visible. (00:07:10)
Continuity mistake: At the end of the episode, Perry and Clark arrive at the intersection to wait for the bus. They walk out into the intersecting road, and the bus arrives, positioned in the middle of the road, since they are standing in the right lane. Perry and Clark say their goodbyes, and a new shot of the bus from behind, shows the bus is in the right lane only as it starts up from the stop.
Plot hole: Mayor Tate and Lex have a discussion about bribes and Tate says this is his 4th term (near the end of the episode, Lex is showing Mayor Tate an attack ad which is saying Tate has been the mayor for the past 12 years and Smallville can't afford another 4 years of Mayor Tate, so it's been 12 continuous years). In last season's episode "Crush", Pete gets a job as a summer intern on Mayor Spiegel's re-election campaign. So how is it possible for Tate to have been on his 4th term when in the previous year Spiegel was Mayor?
Continuity mistake: When Zod/Lex pierces Lana's hand, he pierces it at the same level as Lana's head. But in the camera angle immediately following, Lana's head slide downs the wall and draws level with her hand. (00:20:05)
Vortex (2) - S2-E1
Plot hole: When Nixon and Jonathan are trapped in the crypt after the landslide, Nixon says he can't breathe, and Jonathan says this is because the landslide cut off the air supply. However, we can see beams of sunlight shining in. So, unless the ceiling of the crypt is made of airtight glass, that landslide didn't cut off the entire air supply.
Continuity mistake: When Chloe is first asking Pete and Clark the questions for her poll you can see that the top page on her clipboard is yellow. Then she shows it to Lana and the camera gives you a nice big shot of the front piece of paper and it is white. When Chloe says "its unleashing the inner Lana." the front of the clipboard is shown again and now the paper is yellow.
Vortex (2) - S2-E1
Audio problem: When Lex talks to Clark, Clark clicks his flashlight on, and you hear the click signifying he has turned it on. But in the next shot, the flashlight is now off, without another click sound heard to signify that the flashlight was turned off.
Continuity mistake: When Jason starts knocking on Lana's door, the clasp from the door chain is all the way to the left. The camera cuts to Lana in bed. When it cuts back to the door, the clasp is now all the way to the right.
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.
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