Does the lead that comes on plants affect your water in any way if left in there too long? My plants have just fell out and left the lead on the gravel ?
Depends on size of aquarium compared to the weights, small amounts of lead should be fine but i personally like to remove weights from my plants to allow unrestricted growth if possible. You should be fine.
I like to take the lead off the plants myself. I noticed long ago that if I didn't, the plants tend to rot where they are in contact with the lead. The plants always seem to do better when you can get a bit of space between the strands.