Dr. Bernd Nowack has issued another report on nanosilver. His work was first mentioned in my Sept. 8, 2010 posting which focused on how washing silver nanoparticle-treated textiles releases silver nanoparticles into the wash water. Nowack’s latest work is a report recommending a more stringent approach to studying the risk that silver nanoparticles might pose to the environment. From the Nov. 22, 2010  news item by Lin Edwards on physrorg.com,

Dr. Nowack said one of the risks arises because some of the wastewater and sludge from sewage treatment plants ends up on farms in fertilizers, and could therefore enter the food chain. Another risk is that nanosilver could have a detrimental effect on the nitrifying bacteria that are vital to the effluent treatment processes, and could prevent treatment plants from working properly.

Nowack’s report said in earlier studies some nanosilver had been shown to bond with sulfur in sewage sludge to produce non-toxic silver sulfide nanoparticles, but it is not known how efficient sulfur is at removing biocidal silver.