Continuity mistake: After Clark heats up Alicia's cup of hot chocolate with his heat vision, the steam coming from the cup is thick and rapid in the first shot, but in the next shot hardly any steam is coming from the hot drink.
Continuity mistake: After Lois and Clark find out that Cooper dies, and after Lois leaves, while Clark and Geoff talk about how Lois is trouble Geoff hair keeps going from neat to slightly messed up. When the camera is behind Clark, Geoff's hair is all shaggy on the left side of his face. When the camera is behind Geoff, his hair is fixed so that the loose strands are tucked behind his left ear. These changes repeat throughout the scene.
Continuity mistake: Lois hands two boxes of decorations to Clark for Chloe's party but in the next shot he is holding just one box. The other box reappears when they turn to go into the barn.
Continuity mistake: After Clark saves Lex from the ring of fire we see the area that was burned by the fire. The candle that Shannon used to light the alcohol is no longer on the floor. Since the candle was in the fire it should be partially melted and there would be some evidence of it.
Continuity mistake: As Chloe and Clark talk about their feelings the shoulder protector/pad of Clark's backpack switches position with no help from Clark. At first it is more in front and showing more than a few shots later, again with no help from Clark by shifting the backpack, it is more on top of the shoulder and not as visible.
Transference - S4-E6
Continuity mistake: As Lionel's cellmate tells Lionel "I've always kind of had a thing for pattern recognition." the shot changes mid-sentence. Between changes Lionel's cellmate goes from having his arms crossed, hands holding his elbows, to having his hands almost clasped together.
Continuity mistake: During much of the conversation between Clark and Lana, while in the caves, you can see the cave painting that matches the tattoo on Lana's back is behind her. Then, towards the end of the conversation, she is still standing in front of Clark and during the scene has not moved from that position yet, once she sees the cave painting behind Clark she walks over to it and turns around to face Clark, which puts the painting behind her even though it was already behind her before she moved.
Continuity mistake: As the computer says "Subject seeds exposed to radiation" there is a camera shot showing the temperature monitor in the lower right of the shot. In that shot the readout shows the temperature reading is close to 100% of maximum. Then, in the next shot as the scientist says ".absorption level: as expected" the temperature monitor is now close to 90% as we see it climb up to the 98% they were trying for.
Continuity mistake: Clark goes to see Lex about the dog. Lex, who was about to start a game of pool, breaks a fresh rack. Lex then goes to make his second shot from near the side pocket and as he does you can see there are two striped balls near the rail close to Lex's cue stick. Just after he takes his shot those balls are gone even though those balls had not been hit.
Continuity mistake: Alicia's hair keeps changing as Clark holds her in his arms. In some shots the hair on her right side is messy. When the shot switches to a close up, her hair becomes neatly combed and tucked behind her ear. All of this occurs after Clark burns the rope she was hanging by.
Continuity mistake: The raindrops on Clark's shirt disappear and reappear between shots. Clark's shirt is dry when he turns to Chloe and asks "I'm not normal?" but before and after this his shirt has raindrops on it. This happens again a few moments later as Lois starts to talk about "panicking in times of crisis", Clark turns towards Lois and his shirt is dry.
Continuity mistake: When Clark looks over to Lana, while in the coach's office, she starts to pull up her right sleeve that had slipped down. As Clark says "Lana.what are you doing here?" the shot is behind Lana and her sleeve is down and is showing a lot of her upper arm and shoulder but when the shot switches back to the front of Lana, she has her sleeve pulled up covering most of her upper arm.
Continuity mistake: When Lex comes into Lana's place to confess that he was the reason Jason got fired, we firstly see Lana putting some things into a cardboard box. Then during the following shots, the items visible at the top of the box keep on changing between shots.
Continuity mistake: The guide that was with Lana gets killed by soldiers. When the guide is shot you can hear that the weapon has a silencer on it. About a second later we see this still smoking gun has no silencer on it.
Continuity mistake: As Clark first gets to the bridge at Cherry Hill, the shadows establish the time as either early morning or early evening since the shadows are long. In several shots during this scene the sun suddenly jumps to around noon as the bridge shadow goes from sticking out far to one side to being almost directly under the bridge and the shadow of the semi shortens when Clark is making his super jump.
Continuity mistake: After Krypto comes around the fence we hear one of the two guys say "You got all the bags out of the truck, right?". The camera then pans over to the van and you can see, under the rear of the van, two gas containers. There is a metal one on the left and a plastic one on the right. Krypto starts to run for the truck and we see the containers again only now the metal one is on the right and the plastic one is on the left.
Continuity mistake: While talking about what to name the dog there are several shots of the dog and the metal chain is gone. Then, right at the end of the scene, as the dog puts his paw over his nose, the chain is back.
Continuity mistake: When checking out the armored car robbery, Clark tells Lois to turn left. We then go to on out of car shot where the big red letters of the GMC that Lois is driving are visible. When the 4x4 skids to halt shot its GMC logo is covered in black tape.
Continuity mistake: While Clark is chained up, Chloe uses her fingernails to dig into Clark's chest. You can see that since Clark has had his powers taken away her fingernails draw blood. In the shot of Clark screaming in pain you should see where the blood came from the scratches but there is no blood visible.
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