### "'"'~e.o**sr,..~ ~~** **~~** 

# i 

# 8 t, UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

### :S - 

## 'ffi WASHINGTON D.C ., 20460 lJ (!)

### ~**~**

"

## ~~ OFFICE OF CHEMICAL SAFETY**~l, PRO"'{~V**  AND POLLUTLON PREVENT I ON

MEMORANDUM
S U BJECT:

FROM:

THRU:

TO: September 27, 2012

Revised Product Chemistry, Environmental Fate, and Ecological Effects Scoping Document in Support ofRegistration Review ofPerboric acid, sodium salt, monohydrate (PBSM) PC Code: 011105 DP Barcode: 394845 Decision No.: 455962 Registration Nos.: See Table 1 Petition No(s).: NA Regu l atory Action: Ecological Environmental Scoping Document for Registration Review Risk Assessment Type: Single Case No.: 5007 chemical TXRNo.:NA CAS No.: 10332-33

- 9 MRID Nos. : See Page no . 4 40 CFR: None Srinivas Gowda, Microbiologist, Coordinator

### ~cn\ 

### .....**~vaA ~**  Pat Jennings, Environmental Engineer tUc-**~** Davi d Bays, Microbiologist Risk Assessment and Science upport B Antimicrobials Division (751 OP) Steven Weiss, Acting Branch Chief 

# %..**!/)~** Donna Randall, Ecological Risk Assessment Team Leader Risk Assessment and Science Support Branch (RASSB) Antimicrobials Division (7 51 OP) Seiichi Murasak i, Chemical Review Manager Regulatory Management Branch II Antimicrobials Division (751 OP)

Page 1 of9Executive Summary Sodium perborate monohydrate (PBSM) is an inorganic , perboric acid salt, registered for u se as a household laundry sa nitizer. It was first regi stere d in the United States on October 15 , 1998 as an active ingredient in Tide with Bleach, Tide with Bleach U, Gain with Bleach I, and Gain with Blea c h II. A Reregi stration Eligibility Decision (RED) has not b ee n iss ued by the Agency for PBSM b ecause the initial registration date was after the November 1984, federal mandated cutoff for initiation of the 

### RED process. Currently there i s one com pany with two registered prod ucts, both are end-use produ cts formulated 

### as so luble concentrates, and the active ingredient declaration s are 4.74 and 5.28 percent. All product chemistry d ata re quirements hav e been sati sfied for this active ingredient. In response to a comment received during the 60-day public comment period, the Agency is revisiting its initial d ecis ion to forgo performing an ecological risk assessment on PBSM used as a laundry sanitizer. The Central Valley R egio nal Water Quality Control Board (Central Valley Water Board ) identified impaired water bodi es in California that exceed water quality s tandards for boron and so dium , two degradat es of PBSM , and requested that the Agency con duct an env i ronmenta l risk assess ment for the following degradates of PBSM : hydrogen peroxide, borate, boric acid , and so dium

. In re s pon s e to these concerns, the Agency will p erform an ecologic al ri sk asses s ment of PBSM degradates that are per siste nt e nough to have the potential to enter surface water downstream of wastewater treatment plants as a re su lt of PBSM ' s use as a laundry sa nitizer. The Agency has determined that under ambient conditions prevalent in most surface waters, th e predominant persi stent degradates of PBSM are expected to be boric acid and sodium. Since the envi ronmental fate of PBSM and its degradates i s well

- documented and understood , the Agency does not anticipate the need to requ ire additional env ironmental fate data for this registration review at thi s time. In addition, the Agency does not an ti c ipate the need to require additional ecological effects data at this time. Since many stu die s on effects of PBSM degradates to aquatic organisms are available in the scientific literature, the Agency will review these studies during reg i stration review to deriv e measurement endpoints that will be used in the eco logical risk asse ss ment. The Agency will, how ever, require information on the volume of PBSM produced a s a laundry sanitizer so that it can p erform a down

- th e-drain assessment of degradates that are pers iste nt enough to have the potential to enter surface water downstream of domestic wastewater treatment plant s as a result of PBSM 's use as a laundry sanitizer. The Agency will use the down

- the-drain module ofE

- FAST, version 

### 2.0 to perform thi s assessment. PBSM i s highly reactive in aqueous solution under ambient conditions , instant ly establishing equilibrium with two products: hydrogen peroxide and sodium metaborate. Hydrogen peroxide from this reaction degrades very rapidly to water and oxygen; this reaction 

### i s irreversible. The sodium metaborate from thi s reaction dissociates very rapidly in water to form so dium and boric acid. The pKa value of bori c acid is 9.15 , indicating that at pH=9 approximately 50 p ercent of boric acid will be dissociated and 50 percent will remain in boric acid form. As the pH increases above 9, the percentage of boric acid that will dissociate will tend to increase and tetrahydroxyborate will tend to predominate rather than boric acid. Since 

### the pH 

### of many ambient waters i s typically around 7, 

### boric acid rather than tetrahydroxyborate is
Page 2 of9ex pect e d to be the p redomin ant degradate in s urface water under ambi e nt enviro nm en t al condition s. Boron and so dium are pre sent in the e nvironment as a re sult of natur a l and anthropogeni c s ources. Sodium, b oric a c id, and boron-conta inin g s alts are ubiquitou s in the e nvironment. Sodium and boron o cc ur naturally in soils , wat er , fruit s, vegetable s, and forage crops. Boron i s an essentia l nu trient for plan ts as well a s an essen ti al e l ement for many orga ni s m s; s odium i s an essential element fo r anima ls. Accordin g to per s onal co mmunicatio n s with Mr. Daniel 

### J
. M cClure of California W ater Board 's TMDL Un it , 3 1 water bodies in Ca lif orni a that are impaired due to high concentrations of boro n and so dium are from natural orig in, irr i gation, and pumping, and not fro m pes ticidal s ources. Although the Agency currently h as no information on th e amount of PBSM u se d as a l aundry s anitizer , the amount of bori c aci d a nd s odium ions introduced to the aquatic e nvironment from thi s use ofPBSM is expected to be a fraction of the amounts introdu ced to the aquatic environme nt from natural origins a nd other n o n - pesticidal anthropogenic so urce s s uc h a s irrigation and pumping

. PBSM that is used a s a laundry sanitizer , however, can prov id e an additional s ource of boron and so dium to the aquatic environment downstream of wa s t ewater treatment pl a n ts that receive pers i s te nt d egradates of PBSM from thi s s ource. Thi s additional sou rce of boron and s odium can be a particular con cern in water b odies that ha ve b een d e termin ed to be impaired a s a re s ult of h i gh concentration s o f boron a nd so dium. The Age ncy ha s not c onducted a ri sk a ss e ss men t that s upports a comple te endangered spe c ies determination fo r PBSM and it s degradate , boric acid. Th e eco lo g ical risk a ss essme nt planned during regi s trati o n r e view will allow the Agency to determin e whether PBSM and it s predominant persi stent deg radates, boric acid and sodium has " no ef f ec t " or " may affect" federally listed thr e at e ned o r e ndangered species (listed spec i es) or their de s ignated critical habitats
. When an a ssess ment co n cl ude s that a p es ti c ide 's u se " m ay affect " a li s ted sp ecie s or it s de s igna ted c riti cal habit at, th e Agency w ill co n s ult with the U.S. Fi s h and Wildlife Servic e and/or Nat ional Marine Fi s herie s Service (th e Services), as appropri ate.

Page 3 of9

### Introduction Perboric ac id , s od i um s alt , monohydrat e (PBSM) was fir s t regi s te red as an active ingredient with EPA on O c tober 15, 1998. It' s mol ec ular formula NaB0 3·H2 0 is a representation of the average chemical compo s ition but it's elementary s tructural unit is actually a dimer anion B 2 0 4 (0H)/ , in which two boron atom s are joined by two p e roxo bridges. Pres ently , two end-u se produ c ts (EPs ) are r eg is tered for u s e as a hou sehold laundry sanitizer and thes e are li s ted in Tabl e l

. A Reregi s trati o n Eli g ibility Deci s ion (RED) h a s n ot b ee n iss ued b y EPA for PBSM b ec au se th e initial reg is tr ati o n d ate w as afte r No vemb er 1 98 4 , th e f e derall y mandated cutoff fo r initi at io n o f the RED process. 

### Table 1. Registered Products of PBSM Regi stration Registra tion Co mp an y Form ula ti o n %of Active # Na me Na m e Type Ingredient Th e Proc te r & Gamble S o lubl e 3573 -56 Ti de W i t h Bl e a c h II Com pan y Conce n trate 5. 2 8 

### EP Th e Proc t e r & Gambl e S o lu b l e 357 3

- 58 G a in With Bl e ac h II Co nce ntrate 4. 74 Co mpany 

### EP The Agency ha s conducted a review of the available product ch e mi s try , environmental fate , and ecotoxicity data f or PBSM. Th e findin gs are s ummarized below

. 

### A. Product Chemistry Summary of the Perboric acid, sodium salt, monohydrate (95% TGAI Powder) Common Nam e: Chemical N arne : OPP Chemi c al Code: CAS R e gistry Number: Molecular Formula : Mol ec ular w e ight: Mole c ular S tru ct ure:

Color: Physica l Stat e: Odor: Stability: pH: UV Ni s ible ab s o rpti on: 

### Melti ng p o int: Sodium P e rborate Monohydrate Perbori c a c id, s odium salt , monohydrate d (PBSM) 011105 10332-33

- 9 NaB0 3 .H 2 0 whi ch exi s t s a s a dime r B 2 0 4 ( 0H) 4 2

- 99
. 81 g/m o le

White. Solid Granule s . Odorl ess . The produ c t is s table under ambient c ondition s. 10 (con centrat ion 15

. 2 gil) Not appl ic abl e : ionic s alt. 

### Melting point i s 63 °C at which point it 

### deco mpo ses .
Page 4 o f9Boiling Point: Not applicable , product is not a l iquid. Density: 0.4-0.65 g/ml Dissociation Con s tant (pKa): Not applicable: ionic salt. Log 

### Ko!w: Not applicable because product is an inorganic compound that decomposes in water. So l ubilities: Water: 15-16 g/ 1 at 20 °C Vapor Pressure: This is not app l icable because of the ionic hydrated s tru cture. I t is considered to have negligible vapor pressure. Enforcement Ana l ytical Method: Titration for availab l e oxygen. All product chem istry data requirements have been satisf ied for the active ingredient PBSM (Sou rce: MRIDs 43603601,44425602 and 45198501). 

### B. Environmental Fate Summary For the laundry s anitiz in g use of PBSM, the Agency w ill not require any env ironmental fate data for PBSM or its degradate s at thi s time. Fate and transport guidelines , while applicable for organic chemicals, are gene rall y n o t app l icable to inor ganic chemi cals and s a lt s , such as PBSM and its degradates, and cannot be used to determine environmental fate , transport, and persistence of PBSM and its degradates. Since the environmental fate of PBSM and its degradates is well-unders tood and such information is availab le in the scientifi c literature, the Agency doe s not anticipate the need to require additional env ironmental fate data for this registration rev i ew at thi s time. PBSM is highly reactive in aq ueou s solution under amb ient conditi ons , in s tantly es tabli shing equ ilibrium with two products: hydrogen peroxide and sodium metaborate. Hydrogen peroxide from this reaction degrade s very rapidl y to water and oxygen; this reaction is irreversible. The s od ium metaborate from this reac tion d issociates very rapid l y in water to form sodium and boric acid. The pKa value of boric acid is 9.15 indicating that at pH=9 approximately 50 percent of boric acid will be dissociated and 50 percent will remain in boric acid form

. As the pH increases above 9, the percentage o f boric ac id that will dissociate will tend to increase and tetrahydroxyborate will tend to predominate rather than boric acid. Since the pH of many ambient waters is typically around 7, boric acid rather than tetrabydroxyborate or other polyborates is expected to be the predominant degradate in surface water under ambient environmenta l conditio n s . Boron and sodium are pre s ent in the environment as a result of natural and anthropogenic sources. Sodium, boric ac id , borax, and boron

- containing salts are ubiquitous in the environment. Sodium and boron occur naturally in so ils , water, fruits, vegetables, and forage crops. Boron is an essentia l nutrient for plants as we ll as an essential element for many organis ms; so dium i s an essentia l element for animals. Humans ingest naturally occurring boron in the diet, and there is s ome data to suggest that trace levels are required in the human diet

. PBSM is considered t o be a hydrogen peroxide re leas er that also r eleas es boric aci d , a degradate that does not contr ibute to the pesticidal activity of PBSM. In both terre s trial and aquatic 

### systems, PBSM 

### rapidly degrades to form 

### hydrogen perox ide, water , oxygen , and a minor (<10 % of applied) amount of bora te by bo t h abiotic and bio ti c means. Available boron occurs in nature Page 5 of9in the form of a number of c lo sely related com pounds which differ c hi eflr in the water of hydration associated with the mo lecul e and are not eas il y diff erentiat ed". Reaction of PBSM in Aqueous Solution PBSM hydrolyze s in aqueous so lution to release hydrogen peroxide and so dium metaborate. The following are th e appropriate conversion facto r s for expressing co ncentration s of PBSM (Cp o sM ) as equivalent concen tra tion s of:


### • Boron: CB = CPBSM 

### x 0.108; and 

### • Hydrog en peroxide: CH 2 

### o 2 

## = CPBSM 

### x 0.341 In aqueous solutions at room temperature equilibrium between PBSM and hydro gen peroxide and sodium metaborate is ins tantly e s tabli s he d (see reaction Equation I below)

. 

### + 2 [N aB0 2 ] Equation I Sodium per borate monohydrate Hydrogen p eroxide Sodium me tab orate water Further, the hydr oge n peroxide is remo ved from the equi librium-via d egra dation to active oxygen and water (reac ti on Equation H)-l ead in g to an irreversible shif t of the equilibrium g iv en in Equation I to the degradation products so dium me taborate and wat er . The rel ease of active oxygen a ls o known as s inglet oxygen ( 10 2 ) from hydrogen peroxide is th e ba s is of the pesticidal ac tivity of s odium perborate monohydrate

. 

### + Equation II Hydrog en peroxide water singlet oxygen The degradation product, so dium metaborate , dissociates in water and is p resent primar i ly as dissociated boric acid or as boron (reaction Equation ill and Equation IV ). B oric aci d and borates a

r e naturally occ urrin g co mpounds widely found in so il s, water, and food. The bleaching activity of the perborate s i s a ssoc iated with the hydroge n peroxid e rather than th e boric acid degradate. NaB0 2 

### + Z[H20J**~** Na+ 

## + OH- 

### + H 3 B0 3 Sodium metaborate water Sodium ion Hyroxyl ion B oric acid E quation ill

H

3 B03 

### + H 2 0**~** H + 

### + B(OH 4 )- Boric acid water Hydronium ion Tetrahydroxyborate Equation IV
Reactions ofPBSM and NOBS inside the Washing Machine PBSM and so dium nonanoyloxvbenzenesulfonate (NOBS ; PC Code: 089053 ; CAS#91125-43

- 8) are active ingredient s in th e currently r egi stered l aundr y d eterg ent prod ucts Tid e With Bl each II

1 U
. S. Environmental P rotectio n Age n cy. I 993. Reregi strati on Eligibi lity Decision for Bor i c Acid And Its Sodium Salts. Office of Pr evention, Pesticides an d To xic Substances, Office of Pesti cide Progra m s. September 1993. Page 6 of9(EPA Reg. No. 3573-56) and Gain With Bleach II (EPA Reg. No. 3573

- 58) by the Procter & Gamble Company. NOBS is a l a undry bleach activator for hydrogen peroxide releasing c hemicals such as PBSM

. NOBS produces a highly active laundry bleach from the less reactive hydrogen peroxide. Detergent formulation s containing NOBS are de s igned to help ensure rapid convers ion of NOBS to the peroxy compound i n the wash water. Th e p eroxy compound itself i s al s o s hort-lived due to rapid bleaching activ ity. To be effective in the was h cycle, the peracid precurso r must be highly water-sol uble, undergo rap id and total perhydroly s is, and produce a perac id b leach w ith su rface acti vity. Bleach activators l ike NOBS essentially tran sfer active oxygen from the peroxide to the s tain via the pe raci d

. Rea ctio ns inside the wa s hing machine are summarized below:

• PBSM supplies alkalinity (pH 10). • PBSM h ydro ly ses, releasing hydrogen peroxide. • Hydroge n peroxid e perhydrolyzes NOBS, producing pernonanoic ac id

. NOBS is referre d to as a "bleach act i vator" sin ce it produces a highly ac ti ve laundry bleach pemonanoi c acid from the le ss reactive hydrogen peroxide. These reactions are largely complete within the fir s t two minutes of the wa s h

. • Pemonaic acid bl eac he s laundry soi l s by additions of oxygen and s anitizes laundry. Most of the peracid bleach is consumed 

### in the fir st eight minutes of the wash. 

### q

, p o 

# r(Y 8 'o· Na • 

# +**~** / H

## ~0~ 0

- 0 0

O OH Sodium Nonanoylox y benzen s ulf o nat e ( NOBS ) H ydrogen**pero~tide** Pernonan oic acid laundry bleach
Water Quality Pe sticidal use of s odium perborate sa lt and its d eg radate boric acid are not identified as a cause of impairment for any water b od ie s li sted as impaired unde r section 303(d) of the Clean Water Act, base d on inf ormation provided at the Agency' s National Pesticides Cause of Impairment of Waters website (searched September 20, 2012f In addition, no Total Maximum Daily Loads (TMDL) have been developed for sodium perborate s alt and its degradate boric acid, based on information provided at the Agency's Natio nal Pe st icide TMDL web s ite (searched September 20, 2012) 3

. More information on impaired water bodies and TMDLs can be found at http: //www.ep a.g o v/owow/ tmdll

. The Agency invites sub mission of wate r qua l ity data for thi s pesticide. To the extent possible, data s hould co nform to the quality s tandard s in Appendix A of the OPP Standard Operating Procedure: Inclu sion of Impaired Water Bod y and Other Water Quality Data in OPP 's R egis tration Review Risk Assessment and Managem e nt Process (see: http ://www

. e p a . gov/oppfead 11 cb/ ppdc/20 0 6/ nove mber06/sess ion 1 -sop . pdf ), in order to ensure they can be used quantitatively or qualitatively in pesticide risk a ssess ment s.

2 • hup ://iaspub

.epa. gov/ tmdl w aters I0 /attain s nati on cy . cau se detail 3 0 3 d?p catt <ie gro up id-8 85 3 http ://i as pub.ep a . g ov/lmd l waters I 0/atta in s nati o n . tmdl oollutan t det.ail?p pollutant gro up id=8 85&p pollutan t g ro up name=PESTIC IDES Page 7 of9TMDL P o llu tant: B or on is identified as a cause of impairment, as defined under section 303(d) of the Clean Water Act, for three water bodies in California, eight water bodies in Co l orado, six water bodies in Kansas, four water bodies in New Mexico, one water body in Nevada and one water body in Utah, ba sed on information provided at h ttp://ias pub .e pa . g ov/ tmdl waters lO/attain s impaire d waters . tmdl s? p po llut ant id=23 0

. Impair ed W aters. Cause o f Im pa irment: B oro n : Boron is identified as a cause of impairment , as defined under section 303(d) of the Clean Water Act, for three water bodies in Arizona , nineteen water bodies in Ca li fornia , eleven water bodies in lllinois, one water body in Kansas, two water bodies in New Mexico, eigh t water bodies in Colora do , six water bodies in Kan sas, four water bodi es in New Mexico , sixteen water bodies in Nevada and one water bo dy in Utah, based on information provided at h

tt

p ://of mpub

. ep a.gov/tmdl wa L er s lO/attain s i mpaire d wa ters . co ntro l ? p c au se name =BORON According to Cal iforn ia Water Boards, in Cal i fo rnia there are 31 water bodies that are impaired due to high concentrations of boron. The 2008-2010 Clean Water Act Section 303( d) li s t for Cali fornia contains 15 stream segments in the Centra l Valley, 11 segments in the Central Coast re gion , 4 segments in the Los Angeles regio n , and 1 segmen t in th e Lahontan region that exceed water quality standard s for boron. Only 4 of the tota l 31 water bodies impaired for boron statewide currently have a total maximum daily load (TMDL) in place. http ://www .wat e rb oard s.ca. gov/water iss ues/ program s/ tmdl/inte grated 20 1 O.s html According to personal communi cat ion s with Mr
. Daniel J. M cC lure of Ca liforni a Water Board's TMDL Unit, 31 water bodies in Cali fornia that are impaired due to high concentration s of boron and sodium are from natural origin, irrigation, and pumping, and not from pe stici dal source s. PBSM that is used as a laundry sa niti zer , however, c an provide an additional source of boron and sod ium to the aquatic environment downstream of wastewater treatment plants that receive PBSM degradates from this s ource. This additional s ource of boron and sod ium ca n be a parti c ular co ncern in water bodies that have been determined to b e impaired as a re su lt of high concent ration s of boron and so dium. During registratio n review of PBSM, the Agency will attempt to determine th e co ntribution of PBSM used as a laundry sanitiz er to boron and sodium co ncentrations in impaired water bodies. 

### C. Ecological Effects Summary For the laundry sanitizin g use of PBSM the Agency will not require any additional e nvironmental effects toxicity data at thi s time for the persistent degra dates of PBSM , bori c acid and sodium. Because s tudie s on effect s of these PBSM degradates to aquatic organisms are available in the scie ntifi c literature, the Agency will review these stu die s during registration review to derive meas urement endpoints that will be used in the ecological ri sk as sess ment and will not require any additional ecologica l effects data at this time

. The Agency anticipates using a total toxic residue approach to assess ecological effects for the boron -co ntain i ng degradate s of PBSM, boric acid and bo rat es.

Page 8 of9Based on evidence obtained from an Activated Sludge Resp iration Inhibition (ASRI) study on boric acid, thi s chemical appears to be unlike l y to exhibit adverse effects on wastewater treatment plant microorgani sms. The Agency reviewed an Activated Sludge Respiration Inhibition (ASRl) study of boric acid that was submitted by U.S. Borax Inc. for registration review of zinc borate wh ich concl uded that the ECso for bo r ic acid was greater than 1001 mg/L (memorandum dated April 2 , 2008 from Srinivas Gowda , Chemist , EPA Antimicrobials Divi s ion Ri sk Assessment and Science Support Branch to Mark Hartman , Chief, EPA Antimicrobials Divi s ion Regulatory Manage ment Branch ll, DP341315). Since this concentration of boric acid would be expected to be highly un l ikely to occur in wa s tewater treatment plant influents, boric acid wou ld be very unlikely to reach levels in wastewater treatment plants that would inhibit the respiration of activated s ludge microorgani s ms. 

### Ecological Risk Assessment and Data Needs: Environmental Fate and Ecological Risk: The Agency ha s not conducted a risk assessment that s upports a complete endangered species determination for PBSM and its degradate, boric acid. The ecological risk asse ss ment planned during registration review will allow the Agency to determine whether PBSM and its degradat e, boric acid has "no effect" or " may affect" federally li ste d threatened or endangered s pecie s (listed s pecies) or their de s igna ted critical habitats. Wh e n an as sess ment concludes that a pe s ticide 's use " may affect " a listed species or its de s ignated critical habitat, the Agency will cons u l t w i th the U.S. Fish and Wildlife Service and/or National Marine Fisheries Service (the Services), as appropriate. The Agency wi ll conduct an ecological ri sk assessment for indoor u se of PBSM (as a hou se hold laundry sanitizer inside the washing machine) and it 's degradate boric acid for registrat ion review, including a risk a ssess ment that s upports a complete endangered species determination. To s upport a complete endangered spec ies assessment the Agency will evaluate ri sks to aquatic species from indoor uses of PBSM as a hou se hold laundry san i tizer inside the washing machine, s p ec ifically it 's degradate, boric acid. 

### Environmental Fate and Ecological Effects Data Gaps and Anticipated Work For the laundry sanitizing use of PBSM inside the washing machine the Agency will not require any additional environmental fate or ecological effects information to conduct environmental fate and ecological risk as sess ments planned during regi s tration review. The Agency will, howeve r , require information on vo lum e ofPBSM produced as a laundry sanitizer.

Page 9 of9