i'm doing a planning exercise, and i'm not trying to ask for help on that, but does anyone know why lead is toxic? what does it do to the membrane of cells that impairs their partial permeability? speedy replies greatly appreciated!!

Might want to take a look at this site:

http://www.nlm.nih.gov/medlineplus/leadpoisoning.html

Take care, and welcome to Sciforums.