Concerned about measuring silver nanoparticles in the environment?

Silver nanoparticles are believed to have lower toxic effects than silver in solution (ionic silver).  As discussed in an earlier GEM (Should we be worried about Nanotechnology?) silver nanoparticles have many applications, and can be found in a host of household products, including as a bactericide in clothing.  As a result silver nanoparticles can be released into the environment. Due to the varying toxicity between silver nanoparticles (AgNP) and ionic silver scientists need to be able to measure both these species in environmental samples to find the relative concentrations of each species in water bodies.  Furthermore, with the EU requirements to be able to count particles for AgNPs as well, there has been a need to identify intrumentation capable of counting these particles.  This has led to the  Government Chemist undertaking and publishing a Feasibility study on the quantitative differentiation between nanosilver and ionic silver in aqueous suspension using single particle ICP-MS which can be downloaded here.