Dr. Samuel Luoma has given us an excellent description and analysis of the science of silver and nanosilver. His paper raises many questions for policy makers. Its subtitle, “Old Problems or New Challenges,” is appropriate, because the subject of the paper is both. Metals are among the oldest of environmental problems. Lead, silver and mercury have posed health hazards for thousands of years, and they are as persistent in the environmental policy world as they are in the environment. Nanotechnology is a new challenge, but the scope of the policy issues it presents is as broad and difficult as the technology itself
