It's the episode about contaminated ground water and the guy studying the carps to prove it. It opens with them finding the body of the boy who hung himself because he'd been feminized by all the contaminants in his drinking water when he was a kid. There was a rock song playing during the lab scene with Langham and Helgenberger. The vocals are oddly familiar, but I can't place the group and I don't know the name of the song. If anyone out there knows it, you're awesome! Please make my day and pass it on 