I just got a call back from the pediatrician's office. Pequita's blood lead levels are 1.1, down from a high of 9.25, with 10 being considered toxic levels.
I'm ecstatic. I admit that I teared up when the nurse told me. I was quite worried. Damn clawfoot tub.
I'd appreciate it if anyone reading this make a point of spreading the word that antique cast iron bathtubs and sinks can leach significant lead into the warm water that children bathe in, wash their faces in, and brush their teeth in.