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. Signature: Project No.: 0317.00.005. 580 Page 1 of 2

Project Name: Nanotechnology Treatment Review 

### CBI?

Yes

No TELEPHONE CALL RECOR D Incoming Outgoing Date: 03/15 /2013 Time: 1 :00 am

pm

Company Name: VirginiaTech , CEINT ERG Staff Name: K im Wagoner , Eva Knoth

Contact Name: Michael Hochella Contact Phone Number: 540

- 231

- 6227

General Subject: Request for Information on Nanomaterials Research



### TOPICS DISCUSSED AND ACTION TAKEN

On March 15 , 2013, we called Dr. Hochella to discuss information about nanomaterials and his current research

within the Center for the Environmental Implications of NanoTechnology (CEINT ). We first introduced Dr.

Hochella to EPA’s effluent guidelines process and our current evaluation of nanomaterials in industrial wastewater. We then reviewed our study questions: Where should we focus our efforts, the primary

manufacturers or the industries that use nanomaterials in development of secondary products ? He began by noting that most nanomaterials are naturally occurring, except for carbon nanotubes (CNTs) and fullerenes. We

should consider both the manufacturers of nanomaterials and industries that discharge nanomaterials in wastewater. Most industries may not be aware that nanomaterials are present in the ir waste stream s

.

We asked him to discuss his research regarding nanomaterials in sewage sludge. He described how he and a PhD student, Boje ong Kim analyzed some sewage sludge samples that originated from the 2009 EPA Targeted

National Sewage Sludge S urvey ( EPA 822

- R

- 08

- 014 )

. Originally, t he survey analyzed sludge from 74

munic ipal wastewater treatment plants (WWTPs) across the US for an exten sive list of parameters from organics to heavy metals . The results were published and the samples were locked in storage. The identit y of each sample was protected.

Dr. Hochella’s team wanted to reevaluate the samples for the presence of nanoparticles (wh ich was not previously done). They began by looking at the samples with high silver co ncentrations under a SEM with back scatter imaging to screen for specific areas of the sample that many contain small particles with heavy elements. Then, they looked at those areas under a TEM to identify the composition of the small particles. The y found silver nanoparticles as small as 3 nm, in the form of acanthite (silver sulfide)

. They also looked for other nanoparticles i n the sludge, and found titanium dioxide (TiO 2 ), zinc sulfide and iron sulfide nanoparticles

. Additionally, they found that silver nanoparticles can easily sulfidize within minutes

, at room temperature. Nanoparticle s ulf

idation is a reaction in which silver nanoparticle s complex with sulfides (compounds with

sulfur it an oxidation state of

- 2) to form Ag(2)S. They also found TiO 2 and other transition metal nanomaterials at levels much higher than what would occur naturally, suggesting there is a manmade source of these materials

discha rged to POTWs. Th is finding suggests concern with the application of sewage sludge to agriculture fields

because of toxicity and exposure concerns.

We ask ed if , based on his research, nanomaterials are more likely to partition into the sludge or if they w ould end up in WWTP effluent. Dr. Hochella suggested that we contact Ralf K ä gi of Eawag: Swiss Federal Institute of Aquatic Science and Technology who has conducted practical experiments using a pilot WWTP that may address this question. In general, a nano particle will not settle out of solution unless “attached to carbon bits”

due to its size. He also indicated that TiO 2 is very abundant in sludge and relatively unreactive, insoluble andNeed to return call by / at/between and

. Signature: high ly refractory. However, TiO 2 is a concern with regard to possible impacts on soils because of its catalytic

surface.

He then discussed the abundance of nat urally occurring nanomaterials. “ These far exceed manufactured nanomaterials by orders of magnitude. ” Most metal oxides are naturally occurring. Fuller enes and CNTs are not found in nature, and Dr. Hochella recommended focusing on their presence and behavior. Biology may not be

evolved to handle these.

We followed by asking if manufactured metal oxide nanoparticles would have a significant effect since these materials are already present in nature? Dr. Hochella responded that if the nanomaterials dramatically upset the

concentration balance within an area, they could have a large eff ect (e .g.
, a new mining operation or sludge applied to land that has previously not been exposed to a concentrated metals source ) . He discussed the results of the CEINT mesocosm study, in which mesocosms were doped with man ufactured silver nanoparticles to determine their fate in a natural wetland. As expected, the silver nanoparticles were sulfidized, but surprisingly had a biological effect on the microbial community and plant li fe at very low concentrations (one tenth of a ppm). He also confirmed that there is no toxicity data for the impact of transformed nanoparticles in the

environment.

We asked if manufactured nanomaterials are distinguishable from those that are naturally occurring. Dr. Hochella responded that TiO 2 n anoparticles are probably not. Natu r ally occurring TiO 2 nanoparticles have been found in rivers in Montana (pristine to industrial activity) that are identical to manufactured nanoparticles. He added that we cannot be completely sure if these are naturally occurring because nanoparticles (e.g. CNTs) have been shown to be transported long distances through the atmosphere.

We asked if he could summarize and connect the dots between current research and potential regulation. Dr. Hochella responded it is likel y that we will not have to worry about most nanomaterials at the concentrations that are likely to be present in the environment because to date they haven’t seen any effects; however

, he cautioned that we could be surprised . We need to continue doing rese arch to be able to quickly investigate if or when something goes wrong in order to determine the cause of illness or effects of exposure.

We asked if he could talk about promising analytical methods that could be used for detection or

characterization of nanoparticles. He pointed us towards the National Nanotechnology Network (NNIN), a NSF grant program on its 10 th year , which is currently proposing a Next Generation Network (NG

- NNIN). It is a consortium of 14 universities that provide s infrastructure, in struments and expertise to further research and help outside users solve problems related to nanotechnology. Virginia Tech heads up the geosciences node of the

network. The NG

- NNIN will expand to 18 universities.

Dr. Hochella requested that we update him on our progress and share any publicly

- available reports resulting from our inquiry.