Richard Denison, Ph.D., is a Senior Scientist.

Researchers at Virginia Tech have identified and characterized silver nanoparticles (AgNPs) in the sewage sludge produced by an operating municipal wastewater treatment plant.  The study is notable in several respects:  It is the first time AgNPs have been detected in a field-scale study, one of a real-world operation representative of a real-world exposure scenario to boot.  It shows that silver can exist in wastewater treatment products as nanoparticles.  It indicates such particles may be most likely to partition to sludge under common treatment technologies.  And it suggests that silver may be chemically transformed in the course of wastewater treatment.

The study did not demonstrate that the AgNPs detected in the sludge originated from products containing such nanoparticles, as some news stories have suggested, although the authors indicate such a source “is likely.”  But the findings have important implications for nano safety nonetheless.  Read More »