**UNITED STATES**  **ENVIRONMENTAL PROTECTION**  **AGENCY WASHINGTON, D.C.**  **20460**



### MEMORANDUM: **OFFICE OF**  **CHEMICAL SAFETY**  **AND POLLUTION**  **PREVENTION**
**August 7,**  **2013**



### SUBJECT: **Review of** **MRID 49190801**  **"The Quantification**  **and Characterization**  **of Silver** 

**Released fr** **om Textiles**  **Treated with**  **NSPW-L30SS: As**  **a Result**  **of Simulated**  **Laundering Conditions", Study**  **Number 110112.0001**  **Revision 2,**  **04- 30-** **2013**

**PC Code:**  **072599 DP**  **Barcode: 413873**  **Decision No.:**  **418580 Registration**  **No.: 8461** **0- E**  **Petition No.:**  **NA Regulatory**  **Action: Product**  **Registration**

**- Section**  **3 Risk**  **Assess Type:**  **NA Case**  **No.: 5042**  **TXRNo.:NA CASNo.:NA**  **MRID No.:**  **49019201, 49045301,**  **40 CFR:**  **NA 49190801** 



### FROM: **Timothy Dole,**  **CIH, Industrial**  **Hygienist**

# 0\**� �** 
**�** 

# ])-�

**Risk Assessment**  **and Science**  **Support Branch** **,**

# .**. /**  **Antimicrobials Division**  **(7510P)**



### THRU: **Timothy Leighton,**  **Senior Scientist** 

### c:;:;r;;=**""" ......** **..__ __** 

**Steve Weiss,**  **Chief Risk**  **Assessment and**  **Science Support**  **Branch Antimicrobials**  **Division (7** **51 OP)** 



### TO: **Jed Costanza**  **Ph. D.,**  **Environmental Protection**  **Specialist**

**Regulatory Management**  **Branch I**  **Antimicrobials Division**  **(751 OP)** 

**Attached is**  **a review**  **of MRID**  **49190801. This**  **study is**  **the second**  **revision of** **the original**  **studies (M** **RIDs 49019201**  **and 49045301)**  **which were**  **revised to**  **correct typographical**  **errors and**  **clarif y**  **the procedures**  **used fo** **r sample**  **preparation and**  **analysis. In**  **addition, the**  **two reports**  **(M RIDs**  **49019201 and**  **49045301) were combined into**  **one report**  **(M RID**  **49190801).**

**Page 1**  **of 13** 

### 1.0 **Introduction**

**This study**  **was submitted**  **by NanoSilva,**  **LLC in**  **support of the**  **textile use**  **fo r**  **their proposed**  **product NanoSilva NSPW-L30SS.**  **This product**  **is proposed**  **fo r**  **use as**  **a preservative**  **in synthetic textiles**  **such as**  **polyester. It**  **will be**  **applied as**  **a master**  **batch marketed**  **under the**  **brand**
**name Polyguard.**  **A master**  **batch is**  **a plastic**  **pellet fo** **rmulation that**  **is added**  **to the**  **plastic polymer**  **mixture prior**  **to the**  **production of** **fibers. The**  **proposed application**  **rate in**  **the final**  **treated article**  **is 10**  **to 30**  **ppm silver.**  **The study**  **consisted of** **a washing**  **machine test**  **where fa**  **bric samples**  **were washed**  **in a**  **simulated washer**  **according to**  **the ISO**  **test method**  **fo r**  **colorf astness.**  **The washing**  **fluid consisted**  **of tap**  **water and**  **detergent to**  **simulate laundering**  **conditions that**  **result in**  **down the**  **drain environmental**  **exposures and**  **artificial saliva**  **to simulate**  **saliva contact**  **exposures that**  **occur when**  **toddlers suck**  **or mouth**  **treated textiles.** 



### 2.0 **Materials Tested**

**This study**  **was conducted**  **with polyethylene**  **terephthalate (PET)**  **fa bric**  **samples that**  **had been**  **manuf**

**actured to**  **nominally contain**  **36 ppm**  **silver. This**  **concentration was**  **obtained by**  **using a**  **PET polymer**  **extrusion mix**  **which contained**  **85 percent**  **untreated PET**  **and 15**  **percent master**  **batch. The**  **master batch**  **contained 98**  **percent untreated**  **PET and**  **2 percent**  **Nanosilva NSPW-L30**  **which contains**  **1.19 percent**  **silver (all**  **percentages are**  **by weight).**  **The analytical**  **concentration (listed**  **as the**  **theoretical concentration**  **in the**  **report) was**  **26.2 ppm**  **based on**  **previous analysis**  **of the**  **silver content**  **and recovery**  **rate of**  **95.1 percent**  **fo r**  **NSPW- L30SS**  **and 77.4**  **percent fo** **r the**  **master batch.** 

**The treated**  **fa**

**bric samples**  **were taken**  **from extra-large**  **black knit**  **sport shirts.**  **Control samples**  **were taken**  **from a**  **two meter**  **long piece**  **of untreated**  **white fa**  **bric composed**  **of 100%**  **PET. The**  **fa**

**bric samples used**  **fo r**  **the laundering**  **test were**  **cut to**  **10 x**  **20 em**  **and were**  **not hemmed.**  **These samples**  **had an**  **average weight of** **2.75 grams**  **(n=3). The**  **fa bric**  **samples fo** **r the**  **saliva test**  **were cut**  **slightly larger**  **(1 0 x 22**  **em) and**  **they were**  **hemmed to**  **minimize the**  **fraying that**  **was observed**  **during the**  **laundering test.**  **These samples**  **had an**  **average weight**  **of 3.** **73 grams**  **(n=3).**



### 3.0 **Testing Methods** 

**The test**  **method was**  **modeled after**  **the ISO**  **1 05-C06**  **test method**  **"Colour fa** **stness to**  **domestic and**  **commercial laundering" that**  **was used**  **in Geranio**  **et al.**  **(200 9)**  **and Lorenz**  **et al.**  **(20 12).**  **The ISO**  **test method**  **uses steel balls**  **in a**  **simulated washing machine. The**  **ISO method** 

**was modified**  **fo r**  **this study**  **to include**  **the use**  **of plastic**  **balls instead**  **of steel**  **balls to**  **eliminate the**  **possibility of**  **silver contamination**  **from the**  **steel balls.**  **Also the**  **fa bric**  **samples were doubled**  **in size**  **to 8 x**  **20 em**  **and the**  **amount of** **washing solution was**  **correspondingly increased**  **to 150**  **ml.**

**The washing**  **solution fo** **r the**  **laundering test**  **consisted of** **4 grams**  **per liter**  **of ECE**  **detergent in**  **distilled water**  **at pH**  **10.6. The**  **solution was**  **added to**  **one of** **three separate stainless**  **steel containers**  **and preheated**  **to 40**  **degrees C.**  **After preheating, one**  **treated textile sample was**  **added to**  **each container**  **and washed**  **fo r**  **45 minutes**  **at 40**  **degrees C.**  **The sample**  **was then**  **removed**

**Page 2**  **of 13** **from the**  **container and**  **wrun g**  **out by**  **hand into**  **the container**  **and then**  **the contents**  **of the** 

**contai.tier were**  **poured into**  **an HDPE**  **bottle. The**  **sample, still**  **wet, was**  **placed into**  **a new**  **stainless steel**  **container and**  **rinsed with**  **20 ml**  **of water**  **fo r 5**  **minutes using the**  **washing machine.**  **This rinse**  **cycle was**  **repeated using**  **a new**  **stainless steel**  **container and**  **the two**  **collected rinsing**  **solutions were**  **combined and**  **placed into**  **an HDPE**  **bottle. The**  **samples were**  **then dried**  **and placed**  **into plastic**  **bags fo** **r analysis.** 

**The washing**  **solution fo** **r the**  **saliva test**  **consisted of** **simulated saliva**  **that contained**  **a mixture**  **of sodium,**  **potassium and**  **amm onium**  **salts, potassium**  **thiocyanate, urea,**  **sodium sulf**  **ate decahydrate, calcium chloride decahydrate,**  **potassium phosphate**  **and sodium**  **bicarbonate. The**  **samples were**  **washed in**  **the same**  **manner as**  **the laundering**  **test samples;**  **however, the**  **samples**

**were not**  **rinsed after**  **washing and**  **the process**  **was repeated**  **three times**  **fo r a**  **total of** **nine samples.** 



### 4.0 **Sample Preparation**  **Methods**

**Wash and**  **Rinse Solutions** 

**The wash**  **solution samples**  **were filtered**  **using separate**  **0.45 micron**  **50 mm**  **diameter filters**  **fo r**  **each sample.**  **The filter**  **membranes were then**  **cut into**  **3 x 3 mm**  **pieces and**  **were weighed**  **out into**  **microwave vessels**  **and digested**  **with 3ml**  **HN03 in**  **a CEM**  **digester. After**  **digestion, the**  **sample was**  **diluted to**  **10 ml**  **with deionized**  **water.**

**The filtrate**  **fr om**  **the wash**  **solution sample**  **was collected,**  **placed into**  **a sealed**  **test tube**  **and labeled**  **fo r**  **direct analysis.** 

**Textiles**

**The textile**  **was cut**  **into 3 x 3**  **mm pieces**  **(100 to**  **150 mg)**  **and weighed**  **out into**  **a microwave**  **vessel and**  **digested with**  **3 ml**  **HN03 in**  **a CEM**  **digester. After**  **digestion the**  **control samples** 

**were diluted**  **to 10**  **ml and**  **the treated samples**  **were diluted**  **to 25**  **ml.**



### 5.0 **Sample Analysis** 

**The samples**  **were analyzed**  **with Inductively**  **Coupled Plasma** 

**- Mass**  **Spectrometry (ICP**  **MS). The**  **instrument was**  **calibrated with**  **standards containing**  **10, 20,**  **50, 100**  **and 200 ppb**  **silver in**  **2 percent**  **nitric acid.**  **The resulting**  **calibration line**  **had a**  **correlation coef**  **ficient of**  **greater than**  **0.995.**

**The limit**  **of quantitation LOQ**  **was reported**  **to be**  **0.094 ppb**  **fo r**  **filtrates (i.e.**  **liquids) and**  **9.4 ppb**  **fo r**  **the textiles**  **and filters**  **(i.e. solids).**  **As discussed**  **in Appendix**  **A; however,**  **the Agency**  **evaluated the**  **study data**  **and determined**  **that the**  **actual LODs**  **are 10**  **ppb fo** **r filtrates**  **and 1,000**  **ppb fo** **r solids.** 

**Page 3**  **of 13** 

### 6.0 **Quality Control** 
**Quality control**  **(QC) blank**  **samples included the**  **following:**

**• One**  **untreated polyester**  **fabric sample**  **used for**  **washing in**  **detergent.**

**• Three**  **untreated polyester**  **fabric samples**  **used for**  **washing in**  **saliva.**

**• One**  **filtrate each**  **from untreated**  **textile wash**  **and rinse**  **solutions,**

**• One**  **filter/residue sample**  **each from**  **untreated textile**  **wash and**  **rinse solutions** 

**• Three**  **filtrates each**  **from untreated**  **textile saliva**  **solutions,**

**• Three**  **filter/residue samples**  **from untreated**  **textile saliva**  **solutions.**

**No silver**  **was detected**  **in any**  **of these**  **samples.**
**QC samples**  **included initial**  **calibration verification**  **solutions (ICV)**  **and continuing**  **calibration verification**  **(CCV) solutions**  **of 100**  **ppb, a**  **filter spiked**  **with 5000**  **ppb silver**  **nitrate, untreated**  **fabric spiked**  **with a**  **solution of**  **10 ppm**  **silver nitrate**  **and blank**  **solution spiked**  **with 5000**  **ppb silver**  **nitrate. The**  **results of** **the ICV**  **and CCV**  **samples indicated**  **an average**  **recovery of**  **97. 6**  **ppb (n=14)**  **with a**  **standard deviation**  **of 3.0**  **ppb. Additional**  **information regarding**  **the ICV**  **and CCV**  **samples is**  **included in**  **Appendix A.**  **The results**  **of the**  **spike samples**  **are included**  **in Table**  **1.** 

### Table **1**

**-** 

### Quality **Control Spiked**  **Samples Sa**  **mple Type**  **Sa m**  **ple ID** ***** **Flask# Measured**  **Expected (p**  **pb) (ppb)**  **Silver ni** **trate solution**  **spik e**  **onto fabric**  **Textile Spik** **e SM**  **3889-3 9,600**  **10,000 Silver**  **ni trate** **solution spi** **ke onto**  **fabric Textile**  **Sp ik** **e SM**  **3889-4 9,800**  **10,000 Blank**  **solution sp** **ik ed**  **with silver** **ni trate** 

**- 9a**  **SM 3389-2**  **4,877 5,000**  **before filtration**  **Blank solution**  **sp ik** **ed with**  **silver ni** **trate**

**- 9b**  **SM 3889-1**  **4,885 5,000**  **after filtration**  ***The resu** **lts of** **the ab** **ove sa**  **mples are**  **hs ted**  **on pages**  **116 to**  **118 of** **the stu** **dy re** **port.**



### 7.0 **Results**

**Silver Content**  **of Textiles** 

**The silver**  **content of** **the textiles**  **was analyzed**  **in duplicate**  **for each**  **sample before**  **and after**  **washing. A**  **listing of** **the results**  **is included**  **in Table**  **2 for**  **the samples**  **washed in**  **detergent and**  **in Table**  **3 for**  **the samples**  **washed in**  **saliva.**

**The silver**  **concentration in**  **the textiles**  **prior to**  **washing in**  **detergent ranged**  **from 23,637**  **to 24,931**  **ppb with**  **a mean**  **of 24,198**  **ppb (i.e. 24.2**  **ppm) which**  **was similar**  **to what**  **was expected**  **(26.2 ppm)**  **given the**  **application rate**  **and recovery**  **rates observed**  **in previous studies.**  **The average**  **concentration of**  **silver in**  **the textile**  **after washing**  **ranged from**  **21,594 ppb**  **to 24,047**  **ppb with**  **a mean**  **of 23,182**  **ppb (23.1**  **ppm). The**  **change in**  **the silver**  **content of** **the textile**  **samples ranged**  **from a**  **loss of** **0.61% to**  **a loss**  **of -8.6% with**  **a mean**  **loss of**  **4.3%. The**  **study author**  **noted that**  **some of** **this loss might have been**  **due to**  **fiber release**  **from the**  **edges of** **the samples**  **which were**  **not hemmed.** 

**Page 4**  **of 13** **The silver**  **concentration in**  **the textiles**  **prior to**  **washing in**  **saliva ranged**  **from 24,072**  **to**

**26,109 ppb**  **with a**  **mean of** **25,413 ppb**  **(i.e. 25.4 ppm).**  **The average**  **concentration of** **silver in**  **the textile**  **after washing**  **ranged from**  **24,065 ppb**  **to 26,742**  **ppb with**  **a mean**  **of 25,314**  **ppb (25.3**  **ppm). The**  **change in**  **the silver content**  **of the**  **textile samples ranged**  **from a**  **loss of**  **6.8 %**  **to a**  **gain of**  **5.9% with**  **a mean**  **of -0.34%.**  **These samples**  **were hemmed.** 

**Silver Content**  **of the**  **Laundering Solution**  **and Rinse**  **Water**

**The results**  **fo r**  **the filter**  **and filtrate**  **samples of** **the wash**  **water are**  **given in**  **Table 4**  **and they**  **indicate that**  **1.6 percent**  **of the**  **silver in**  **the textile was**  **released. All**  **of the**  **results were**  **less than**  **the LODs**  **and values**  **of one**  **half the**  **LOD were**  **used in**  **accordance with**  **OPP Policy**  **(US EPA,**  **2000) to**  **calculate the**  **amount of** **silver released.** 

**Silver Content**  **of Saliva**  **Wash Solution** 

**The results**  **fo r**  **the filter**  **and filtrate**  **samples of** **the saliva**  **are given**  **in Table**  **5 and**  **they indicate**  **that 0.9**  **percent of** **the silver**  **was released.**  **All of** **the results**  **were less**  **than the**  **LODs and**  **one half** **the LOD**  **was used**  **in the**  **calculations.**



### 8.0 **Conclusions**

**The study**  **indicates that**  **1.6 percent**  **of the**  **silver in**  **NanoSilva treated**  **polyester fa**  **bric is**  **released during**  **washing in**  **detergent and**  **0.9 percent of** **the silver**  **is released**  **during washing**  **in simulated**  **saliva. The**  **study is**  **acceptable and**  **can be**  **).lsed fo** **r risk**  **assessment.**



### References
**Geranio, 2009.**  **The Behavior**  **of SilverNanoparticles**  **during Washing.**  **Geranio, L.,**  **Heuberger, M.,**  **Nowack, B.,**  

## Environmental Science **and Technology**  **43:8113-8118, September,**  **2009.**

**Lorenz, C.,**  **Windler, L.** **, von**  **Goetz, N.**  **et al.**  **2012. Characterization**  **of silver**  **release from**  **commercially available**  **functional (nano)**  **textiles.** 

## Chemosphere **89:817-824.**

**US EPA,**  **2000. Assigning**  **Values to**  **Nondetected!Non- Quantified**  **Pesticide Residues in**  **Human Health**  **Food Exposure**  **Assessments, Office**  **of Pesticide**  **Programs, U.S.**  **Environmental Protection**  **Agency, March**  **23, 2000** 

**Page 5**  **of 13** 

### Table **2- Silver**  **Content of** **Textile Samples**  **Washed in**  **Detergent Change**  **in Silver**  **Before Washin2 (Addendum**  **4) After**  **Washing (Addendum**  **6) Content**  **Sample ID**  **Sampl Fla** **sk# Silver**  **in Textile**  **Silver in**  **Sampl Flask#**  **Silver in**  **Textile Silver**  **in ugH**  **Percentc**

**e# (u**  **glkg) Textile** **(**

**ug )A**  **e# (**  **uglk g)**  **Textile (u** 

**g t**  **3092012-Al I**  

### M0544-l **24,199 66.6**  **2 M3889-35**  **24,197 66.5**  **Duplicate M0544-2**  **23,851 65.6**  **M3889-36 23,614**  **64.9 Avera**  **g e**  **24,025 66.1**  **23,906 65.7**  **0.40 -0.61**  **3092012-A2 2**  **M0544-7 24,158**  **66.4 3**  **M3889-37 23,793**  **65.4 Du** **plicate M0544-8**  **25,703 70.7**  **M3889-38 24,301**  **66.8 Average**  **24,931 68.6**  **24,047 66.1**  **2.5 -3.6**  **3092012-A3 3**  **M0544-13 24,076**  **66.2 4**  **M3889-40 21,594**  **Duplicate M0544-14**  **23,198 63.8**  **N/A Average**  **23,637 65.0**  **21,594 59.4**  **5.6 -8.6**  **Average (n** **=3 )**  **24,198 66.6**  **23,182 63.7**  **2.8 -4.3**  **A. Silver**  **in textile**  **(ug) =**  **Silver in**  **Textile (u** **glk g)** ***** **weight of** **textile**

### (**2.75 gm)** * **0.001 gm!kg**  **B. Silver**  **Released (ug)** **= Silver**  **in textile before washing**  **(ug)**

**- Silver**  **in textile**  **after was** **hing (ug)**  **C.** 

### Silver **Released (percent)**  **= [Silver**  **released (ug**  **) I**  

### Silver **in textile**  **before washi** **ng (ug** **)] *** **100**

**Page 6**  **of 13** 

### Table **3- Silver**  **Content of** **Textile Samples**  **Washed in**  **Saliva Solution** 

**Before Washine (Addendum**  **7) After**  **Washine (Addendum**  **9) Sampl**  **Flask #**  **e#** 

### Textile **ID 3092012-A1-1**  **1 M2422-1**  **Duplicate M2422-2**  **Avera g**  **e 3092012-A1-2**  **2 M2422-3**  **Duplicate M2422-4**  **Average 3092012-A1-3**  **3 M2422-5**  **Duplicate M2422-6**  **Avera g**  **e 3092012-A2-1**  **4 M2422-7**  **Duplicate M2422-8**  **Average 3092012-A2-2**  **5 M2422-9**  **Duplicate M2422-10**  **Average 30920** **12-A2-3 6**  **M2422-11 Duplicate**  **M2422-12 Avera**  **ge 3092012-A3-l**  **7 M2422-13**  **Duplicate M2422-14**  **Average 3092012-A3-2**  **8 M2422-15**  **Duplicate M2422-16**  **Average 3092012-A3-3**  **9 M2422-17**  **Duplicate M2422-18**  **Ave rage**  **Average (n** **=9) Silver**  **in Textile**  **(ug/kg) 25,232**  **25,372 25,302**  **26,831 26,262**  **26,547 26,207**  **25,371 25,789**  **23,178 24,967**  **24,073 25,289**  **26,781 26,035**  **25,776 23,106**  **24,441 26,897**  **25,322 26,110**  **26,278 23,628**  **26,391 24,862**  **26,504 25,683**  **25,597_± 850**  **Silver in** 

**TextileA (ug)** 

**94.1 94.6**  **94.4 100.1**  **98.0 99.0**  **97.8 94.6**  **97.1 86.5**  **93.1 89.8**  **94.3 99.9**  **97.1 96.1**  **86.2 91.2**  **100.3 94.4**  **97.4 98.0**  **88.1 93.1**  **92.7 98.9**  **94.1 94.8**  **+ 3.1**  **Sampl Flask#** 

**e#**

**4 Mag**  **7 Mag**  **S**

**5 Mag**  **9 Mag**  **10**

**6 Mag**  **11 Mag**  **12**

**7 Mag**  **13 Mag**  **14**

**8 Mag**  **15 Mag**  **16**

**9 Mag**  **17 Mag**  **18**

**10 Mag**  **19 Mag**  **20**

**11 Mag**  **21 Mag**  **22**

**12 Mag**  **23 Mag**  **24**

**A. Silver**  **in textile (ug)**  **= Silver**  **in Textile** **(ug/kg ) ** * **wei ght**  **of textile** **(3 .73**  **gm)******* **0.001 gml**  **kg Silver**  **in Textile**  **(ug/kg)**

**25,116 23,014**  **24,065 24,834**  **26,327 25,581**  **25,325 23,198**  **24,262 24,293**  **26,204 25,249**  **26,984 26,499**  **26,742 23,758**  **24,840 24,299**  **25,351 23,715**  **24,533 26,563**  **26,373 26,468**  **26,415 26,841**  **26,628 25,314**  **+ 1,090** 

**B. Silver**  **Released (ug)** **= Silver**  **in textile** **before washi** **ng (u** **g )-**  **Silver in**  **textile after**  **washing (u** **g )**  **C.** 

### Silver **Released (percent)**  **= [Silver** **released (ug)**  **I** 

### Silver **in textile**  **before washing** **(ug)]** ***** **100**

**Page 7**  **of 13**  

### Silver **in Textile**  **(ug)**

**93.7 85.8**  **89.8 92.6**  **98.2 95.4**  **94.5 86.5**  **90.5 90.6**  **97.7 94.2**  **100.7 98.8**  **99.7 88.6**  **92.7 90.6**  **94.6 88.5**  **91.5 99.1**  **98.4 98.6**  **98.5 100.1**  **99.3 94.4**  **+ 4.0**  

### Change **in Silver** 

**Content ugl:j**  **Percentc**

**-4.6 -4.9** 

**-3.6 -3.6** 

**-6.6 -6.8** 

**+4.4 +4.9** 

**+2.6 +2.7** 

**-0.6 -0.7** 

**-5.9 -6.1** 

**+5.5 +5.9** 

**+5.2 +5.5**  **-0.4+ 4.9**  **-0.34 +**  **5.2**

### Table **4- Amount**  **of Silver**  **Released following**  **Washing in**  **Detergent Silver**  **in Textile**  

### Water**(LOD** 

### = **10 uglliter)**  **Filter/Residue (LOD**  

### = **1000 uwk�:)**  **Silver Released**  **Sample I.** **D. Before**  **WashingA Sample**  **Flask# Silver**  **Silve�·c Sample**  **Flask# Silver**  **Filter Silver"·**  **u** 

### ugE **Percenr #**  

### (\lgLL) **(ug) #**  

### (uglkg) **(gm) (ug)** 
**Wash Water** **(Addendum 5**  **3092012-A1 66.1**  **ug 2a**  **3889-5 <LOD**  **0.75 2c**  **M3889-7 <LOD**  **0.10 0.05**  **0.80 3889-6**  **<LOD 0.75**  **M3889-8 <LOD**  **0.10 0.05**  **0.80 3092012-A2**  **68.6 ug**  **3a 3889-9**  **<LOD 0.75**  **3c M3889-11**  **<LOD 0.10**  **0.05 0.80**  **3889-10 <LOD**  **0.75 M3889-12**  **<LOD 0.10**  **0.05 0.80**  **3092012-A3 65.0**  **ug 4a**  **3889-13 <LOD**  **0.75 4c**  **M3889-15 <LOD**  **0.10 0.05**  **0.80 3889-14**  **<LOD 0.75**  **M3889-16 <LOD**  **0.10 0.05**  **0.80**



### Rinse **Water (Addendum**  **5 3092012-Al**  **66.1 ug**  **6a 3889-21**  **<LOD 0.20**  **6c M3889-23**  **<LOD 0.10**  **0.05 0.25**  **3889-22 <LOD**  **0.20 M3889-24**  **<LOD 0.10**  **0.05 0.25**  **3092012-A2 68.6**  **ug 7a**  **3889-25 <LOD**  **0.20 7c**  **M3889-27 <LOD**  **0.10 0.05**  **0.25 3889-26**  **<LOD 0.20**  **M3889-28 <LOD**  **0.10 0.05**  **0.25 3092012-A3**  **65.0 ug**  **8a 3889-29**  **<LOD 0.20**  **8c M3889-31**  **<LOD 0.10**  **0.05 0.25**  **3889-30 <LOD**  **0.20 M3889-32**  **<LOD 0.10**  **0.05 0.25**  

### Total **Amount of** **Silver Measured**  **in Wash**  **and Rinse**  **Water 3092012-Al**  **1.05 1.6**  **3092012-A2 1.05**  **1.5 3092012-A3**  **1.05 1.6**  

### Average **1.6**

**A. Average**  **of two** **replicate analyses**  **as listed**  **in Table**  **I of** **this review.**  **B. Results**  **were less**  **than the**  **LOD. Used**  **LOD/2 for**  **silver content**  **calculations. C.**  **Silver in**  **Wash Water**  **(ug) =**  **Wash Water**  **Silver (ug/liter)**  ***** **Flask Volume**  **(0.15 liter**  **for wash**  **water samples**  **and 0.040**  **liter for**  **rinse water**  **samples) D.**  **Silver in**  **Filter/Residue (ug)**  **= Silver**  **in Filter/Residue**  **(uglkg)** ***** **Filter Weight**  **(gm)** *******0.001 kg/gm**  **E. Silver**  **Released (ug)**  **= Wash**  **Water Silver**  **(ug) +**  **Filter/Residue Silver**  **(ug) F.**  **Percent Silver**  **Released =** **Silver Released**  **(ug) I**  **Silver in**  **Fabric Samples**  **(ug).**

**Page 8**  **of 13** 

### Table **5- Amount**  **of Silver**  **Released following** **Washing in**  **Saliva Water** **(LOD =**  

### 10 **uglliter Filter/Residue** **(LOD =**  

### 1000 **ug/k2] Silver**  **Released Silver**  **in Textile**  **Sample Flask#**  **Silver Silve�**  **Sample Flask#**  **Silver Filter**  **wt** 

### Silver'- **ugu Percent"'**  **Sam_Q_le I.D.**  **Before WashingA**  **# (ug/**  **liter) (**  **u g**  **) #**  

### (uglkg) **( g**  **m) (ug)** 



### Wash **Water (Addendum**  **8) 3092012-A1-1**  **94.4 ug**  **4a 1219-12**  **<LOD 4c**  **Ml220-7 <LOD**  **0.130 0.065**  **1219-16 <LOD**  **Ml220-8 <LOD**  **0.122 0.061** 

**<LOD 0.75**  **<LOD 0.063**  **0.81 0.86**  **30920 12-A** **1-2 99.0**  **ug Sa**  **1219-17 <LOD**  **Sc Ml220-9**  **<LOD 0.122**  **0.061 1219-18**  **<LOD M1220-10**  **<LOD 0.109**  **0.055**

**<LOD 0.75**  **<LOD 0.058**  **0.81 0.82**  **3092012-Al -3**  **97.1 ug**  **6a 1219-21**  **<LOD 6c**  **Ml 220-l**  **l <LOD**  **0.123 0.062**  **1219-22 <LOD**  **Ml 220** **-12 <LOD 0.128**  **0.064**

**<LOD 0.75**  **<LOD 0.063**  **0.81 0.83**  **30920 12-A2-** **l 89.8**  **ug 7a**  **1219-25 <LOD**  **7c Ml220-13**  **<LOD 0.118**  **0.059 1219-26**  **<LOD Ml** **2 20-14**  **<LOD 0.111**  **0.056**

**<LOD 0.75**  **<LOD 0.058**  **0.81 0.90**  **3092012-A2-2 97.1**  **ug 8a**  **1219-29 <LOD**  **8c Ml** **2 20-15**  **<LOD 0.115**  **0.058 1219-30**  **<LOD Ml** **2 20-16**  **<LOD 0.113**  **0.057**

**<LOD 0.75**  **<LOD 0.058**  **0.81 0.83**  **3092012-A2-3 91.2**  **ug 9a**  **1219-33 <LOD**  **9c Ml** **2 20-17**  **<LOD 0.109**  **0.055 1219-34**  **<LOD Ml** **220 -18**  **<LOD 0.110**  **0.055**

**<LOD 0.75**  **<LOD 0.055**  **0.81 0.89**  **3092012-A3-1 97.4**  **ug lO** **a 1219-37**  **<LOD lO** **c Ml** **2 20-19**  **<LOD 0.112**  **0.056 1219-38**  **<LOD Ml** **220-20 <LOD**  **0.111 0.056** 

**<LOD 0.75**  **<LOD 0.056**  **0.81 0.83**  **3092012-A3-2 93.1**  **ug lla**  **1219-41 <LOD**  **llc Ml** **220-21 <LOD**  **0.120 0.060**  **1219-42 <LOD**  **Ml 220-22**  **<LOD 0.115**  **0.058**

**<LOD 0.75**  **<LOD 0.059**  **0.81 0.87**  **3092012-A3-3 94.1**  **ug 12a**  **1219-45 <LOD**  **12c Ml** **220-23 <LOD**  **0.117 0.059**  **1219-46 <LOD**  **Ml220-24 <LOD**  **0.118 0.059** 

**<LOD 0.75**  **<LOD 0.059**  **0.81 0.86**  

### Overall **Mean ±** 

### SD **{n =** 

### 9) **0.81 0.85_±0.029**  **A. Average**  **of two**  **replicate analyses as**  **listed in**  **Table 3**  **of th1s**  **review. B.**  **Silver in**  **Wash Water**  **(ug) =**  **Wash Water**  **Silver (ug/liter)**  ***** **Flask Volume**  **(150 ml)**  *******0.001 liter/ml**  **C. Silver**  **in Filter/Residue**  **(ug) =**  **Silver in**  **Filter/Residue (uglkg)**  ***** **Filter Weight**  **(gm)** *******0.001 kg/gm**  **D. Silver**  **Released (ug)**  **= Wash**  **Water Silver**  **(ug) +**  **Filter/Residue Silver**  **(ug) E.**  **Percent Silver**  **Released =** **Silver Released**  **(ug) I**  **Silver in**  **Fabric Samples**  **(ug). F.**  **All results**  **were less**  **than the**  **LOD. Used**  **LOD/2 for**  **silver content**  **calculations.**

**Page 9**  **of 13** 

### Appendix **A- Calculation**  **of the**  **Detection Limit**  **for the**  **NanoSilva Study:**  **The Quantification and** 

**Characterization of**  **Silver Released**  **from Textiles**  **Treated with**  **NSPW-L30SS as**  **a Result of Simulated**  **Laundering Conditions** 

**This appendix**  **documents how**  **the detection**  **limit included**  **in the**  **Nanosilva study**  **is not**  **valid and**  **calculates a**  **recommended level**  **of detection.**  **These calculations**  **are based**  **on a**  **review of** **the procedures**  **detailed in**  **the OPP**  **Position Paper: Assigning Values**  **to Non-Detected/Non-** **Quantified Pesticide Residues**  **in Human**  **Health Food**  **Exposure Assessments (US**  **EPA, 2000).**



### 1. **MDL of0** **.0 09** **4 p.g/L**  **is Not**  **Valid**

**In Section**  **8.1.2 of** **the Nanosilva**  **Study, the**  **method detection level**  **(M DL)**  **fo r**  **silver is**  **stated as**  **0.0094**
**J..l g/L**  **fo r**  **liquid samples and**  **0.94 J..l** **g/kg fo** **r solid**  **samples. As**  **stated in**  **Section 7.2.2**  **of the**  **Nanosilva Study,**  **the MDL**  **represents the**  **minimum concentration**  **of silver**  **that can**  **be identified**  **and reported**  **with 99%**  **confidence that**  **the silver**  **concentration is**  **greater than**  **zero, which**  **is consistent with**  **the definition** 
**at 40**  **CFR 136.**  **In Section**  **8. 1.3**  **of the**  **Nanosilva Study,**  **it is**  **stated that**  **the limit**  **of quantitation**  **(LOQ) is**  **0.094 J..l** **g/L fo** **r liquid**  **samples and**  **9.4 J..l** **g/kg fo** **r solid**  **samples. The**  **LO Q**  **is defined**  **in Section**  **7.2.3 as**  **being I** **0 times**  **the MDL, which**  **was previously**  **communicated to**  **Nanosilva in**  **a phone**  **call on**  **January 25,**  **2013.**

**The MDL**  **and LOQ**  **described above**  **dif fe** **r from**  **the detection**  **limits described**  **in the**  **OPP position**  **paper**

**on assigning values**  **to non-** **detected results**  **fo r**  **pesticide residues**  **in human**  **health fo** **od exposure**  **assessments (US**  **EPA, 2000).**  **In this**  **position paper,**  **EPA introduced**  **the term**  **limit of** **detection (LOD)** 

**as:**

**Limit of** **Detection (LOD)**  **is defined**  **as the**  **lowest concentration**  **that can**  **be determined**  **to be**  **statistically different**  **from a**  **blank. This concentration**  **is recommended**  **to be**  **three standard**  **deviations above**  **the measured average**  **dif f**  **erence between**  **the sample**  **and blank**  **signals which**  **correponds to**  **the 99%**  **confidence level.**

**This value**  **is calculated**  **based on**  **the expected**  **instrument response**  **fo r**  **calibration samples.**  **The Inductively**  **Coupled Plasma**  **Mass Spectrometer**  **(ICP- MS)**  **responses to**  **silver calibration**  **samples analyzed**  **on December**  **1, 2012**  **(page 59**  **of the**  **Nanosilva Study)**  **are shown**  **in Table**  **1.**

**Page 10**  **of 13** 

### Table **1- Estimated**  **LOD and**  **LOQ Based**  **on Calibration**  **Results from**  **1 2 /01/**  **20 1 2**  

### Concentration **ICP-MS Response**  **Expected (CPS** 

**- Expected**  **CPS) (CPS** 

**- Expected**  **CPS)"'2 (Jlg/L)**  **(CPS) CPS**  **0 697.81**  **-99008.43 99706.24**  **9941334226.02 10**  **354265.00 360540.16**  **-6275.16 39377663.10**  **20 805784.43**  **820088.75 -14304.32**  **204613697.89 50**  **2186578.84 2198734.53**  **-12155.69 147760813.94**  **100 4352969.14**  **4496477.49 -143508.35**  **20594646764.41 200**  **9168500.70 9091963.41**  **76537.29 5857956552.45**  **Slope 45954.86**  **Sum 36785689718**  **Intercept -99008.43**  **RMS E**  **110733**

**Based on**  **the OPP**  **position paper,**  **the LOD**  **is determined**  **from the**  **root mean**  **square error**  **(RMSE) from**  **the observed**  **vs. expected**  **ICP-MS response.**  **The LOD**  **is estimated**  **as 3**  **times the**  **R M SE**  **or:**



### 3 **X** 

### 110733 **+** 

### 99008.43 **Liquid LOD**  **=** 

### 45954.86 **=** 

### 9.4Jlg/L

**The concentration**  **of 9.4**  **J.lg/L is**  **the lowest**  **concentration of** **silver that**  **can be**  **determined to**  **be statistically**  **different from**  **the sample**  **that did**  **not contain**  **silver (i.e.,**  **0 J.lg/L).**  **The equivalent**  **concentration fo** **r silver**  **in a**  **filter sample**  **is:**



### 9.4 **Jlg silver**  **10 mL**  **L 1000** **g Filter**  **LOD (llgfkg)**  **=** 

### - **940 Jlg/kg**  **L water**  **digest 1000** **mL 0.1** **g filter**  **kg -** 

**The OPP**  **position paper**  **also introduces**  **the limit**  **of quantitation**  **(LOQ), which**  **is defined**  **as the**  **level above,**  **which quantitative**  **results may**  **be obtained.**  **This is**  **estimated as**  **10 times**  **the RM** **SE or:** 



### 10 **X** 

### 110733 **+** 

### 99008.43 **LOQ =**  

### 45954.86 **=** 

### 26·2 **Jlg/L**

**According to**  **the OPP**  **position paper,**  **these estimates**  **fo r**  **LOD and**  **LOQ fo** **rm the**  **basis fo** **r determining**  **the method**  **detection limit and**  **method quantitation limit**  **which would**  **involve analyzing**  **seven samples**  **containing silver at**  **9.4 or**  **26.2 J.lg/L,**  **respectively. This**  **step was**  **not done**  **for the**  **Nanosilva Study**  **because they**  **established the**  **MDL according**  **to Consumer**  **Product Saf**  **ety Commission**  **Method CPSC**  **CH- £1002-** **08. 1.**  **In the**  **CPSC method, the**  **instrument detection limit**  **(IDL) is**  **first determined**  **from the**  **analysis of** **calibration samples**  **that do**  **not contain**  **silver (i.e.,**  **calibration blank).**  **From this**  **analysis, an**  **IDL of** **0.012 J.lg/L**  **was reported**  **(Table 8 of** **the Nanosilva**  **Study). The**  **IDL was**  **validated by**  **analyzing**

**a sample**  **with silver**  **concentration of** **0.012 J.lg/L**  **seven times**  **with a**  **reported a**  **MDL of**  **0.0094 !J.g/L.**  **However, there**  **was no**  **comparison between**  **the ICP-MS**  **response fo** **r the**  **0.012 !J.g/L**  **sample to**  **the ICP**  **MS response**  **fo r**  **the 10**  **silver calibration blanks.**

**Table 2**  **contains the**  **average and**  **standard deviation fo** **r the**  **ICP-MS response**  **from 7**  **samples fo** **rtified with**  **silver at**  **0.012 J.lg/L**  **and the**  **10 calibration**  **blank samples.**  **This comparison**  **shows that**  **the ICP-MS** 

**Page 11**  **of 13** **response for**  **samples containing**  **0.012 J..l** **g/L silver**  **were not**  **statistically different**  **from the**  **10 calibration**

**blank samples**  

## (students-t **= 0.28).**  **Therefore, these**  **results cann** **ot be**  **used to**  **establish the**  **LOD or**  **LOQ based**  **on the**  **OPP position**  **paper on**  **assigning values**  **to non-** **detected results**  **for pesticide**  **residues in**  **human health**  **food exposure**  **assessments (US**  **EPA, 2000).** 



### Table **2- ICP-MS**  **Response for**  **Silver Free**  **and Silver**  **Containing Samples**  **Samples that**  **do not**  **contain ICP-MS**  **Response Samples**  **fortified ICP-MS** **Response silver**  **(i.e., calibration**  **blank) (CPS)**  **with 0.012**  

### p.g/L **silver (CPS)** 

**Blank1 768.94**  **R-Blank1 720.03**  **Blank2 727.26**  **R-Blank2 662.81**  **Blank3 916.16**  **R-Blank3 621.14**  **Blank4 773.92**  **R-Blank4 826.15**  **Bla nkS**  **852.82 R-Blank5**  **858.93 Blank6**  **763.92 R-Blank6**  **811.15 Blank7**  **542.80 R-Blank7**  **823.37 BlankS**  **415.01 Blank9**  **396.13 Blank10**  **616.69 Average** **± Sta** **nd ard** **Deviation 677±178**  **761±92**



### 2. **Determining the**  **LOD**

**To establish**  **an LOD,**  **Nanosilva should**  **have analyzed**  **a sample**  **with silver**  **concentration of** **9.4 J..l** **g/L at**  **least seven**  **times and**  **reported the**  **recovery of**  **silver at**  **this concentration.**  **Since this**  **step was not**  **performed, EPA**  **is establishing**  **an LOD**  **based on**  **the seven**  **calibration sample**  **analysis results**  **available in**  **the Nanosilva Study. Determining**  **the RMSE**  **for the**  **calibration sample**  **analysis results reveals**  **that the**  **LOD ranges**  **from 0.6**  **to 24.4**  **J..l g/L**  **(Table 3)**  **where the**  **average LOD**  **is 10**  **J..l g/L,**  **which also**  **is the**  **lowest calibration**  **sample concentration.** 



### Table **3 - LOD**  **and LOQ**  **Determined from**  **Eight Calibration**  **Results Date**  **of Calibration**  **Sample Analysis**  **LOD** 

## Jtg/L) **LOQ Jtg/L)** 

**12/112012 9.4**  **26. 3**  **11112/2012 0.6**  **4.8 1116/2012**  **3. 7**  **12.5 11** **120/2012 3.** **3 12.6**  **12/20/2013 11.6**  **32.5 12/21/2012**  **24.4 65.9**  **12/2112012 16.4**  **45. 2** 

**Average (J..l** **g/L) 10**  **29 Concentration**  **for solids**  **samples (J..l** **g/kg) 1000**  **2900**

**Although no**  **independent samples with**  **concentration of**  **10 J..l** **g/L were**  **analyzed to**  **validate the**  **LOD of**  **10 J..l** **g/L, independently**  **prepared calibration-** **check samples**  **with concentration**  **of 100**  **J..l g/L**  **were**

**Page 12 of**  **13 analyzed.**  **Table 4**  **shows that**  **the analysis**  **of the**  **I O O**  **J..L g/L**  **samples had**  **recoveries between**  **93.6 and** 

**I 02.** **7%, which**  **are well within**  **the goal**  **of 70**  **to II**  **0% according**  **to the**  **OPP position**  **paper. Based on the**  **strength of** **the recovery**  **for the**  **I 00**  **J..L g/L**  **calibration check**  **samples, EPA**  **is setting**  **the LOD**  **as I 0** 
**J..L g/L**  **for liquid**  **samples and**  **I 000**  **J..L g/kg**  **for solids**  **samples. In**  **accordance with**  **the OPP**  **position paper,**  **EPA will**  **replace any**  **silver concentration**  **that is**  **below I 0**  **J..L g/L**  **with the**  **value of**  **5 J..L** **g/L and**  **any solids**  **concentration of** **less than**  **I 000 with**  **the value**  **of 500**  **J..L g/kg.** 



### Table **4**

**-** 

### Analysis **of Calibration**  **Check Samples**  **Date of** **Analysis Sample**  **Name Concentration**  **Recovery** 

### (%) 

## (f.lg/L) **I I /I2** **/2 0I2**  **CCV I 0** **1.5 I 0** **1.5 I 1** **1I2 /20** **I2 rev**  **I 0 2.7**  **I 0 2.7**  **11120/20 I2**  **CCV I**  **I 0 0.7**  **I 0 0.7**  **I I /**  **20/20 I2**  **CCV4 93.6**  **93.6 11/20/20** **I2 CCV2**  **95.7 95.7**  **I 2 / I** **8/2 0I2**  **rev 95.0**  **95.0 I 2** **/I8 /2** **0I2 CCV**  **95.3 95.3**  **I 2 /I8** **/2 0I2**  **CCV2 93.9**  **93.9 I 2** **/20/20 I2**  **CCV2 I 0** **0.4 I 0** **0.4 I 2** **/20/20 I2**  **CCV3 99.4**  **99.4 I 2** **/20/20 I2**  **CCV4 98.9**  **98.9 I 2** **/2 I /**  **2 0I2**  **rev 94.9**  **94.9 I 2** **/21120 I2**  **CCV I**  **97.7 97.7**  **I 2 /21120** **I2 CCV2**  **97. I**  **97. I**  **Average ±**  **standard deviation**  **97.6 ±**  **3.0 97.6** 

**Page 13**  **of 13**