### UNITED STATES ENVIRONMENTAL PROTECTIONAGENCY WASHINGTON D.C., 20460

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION

September 13, 2012



### MEMORANDUM

SUBJECT:

FROM:

THRU:

TO: Responses to Central Valley Regional Water Quality Control Board's 60-Day Public Comments on the Registration Review Preliminary Work Plan for PBSM.

PC Code: 011105 DP Barcodes: 404927 DecisionNos.: 469105 RegistrationNos.: None PetitionNo(s).: NA Regulatory Action: Response to 60- Day Public Comments Risk Assessment Type: Single Case No.: 5007 chemical TXRNo.:NA CAS No.: 10332-33-9 MRID Nos. :None 40 CFR: None

Srinivas Gowda, M.S. Microbiologist

## <>~**..J~~** PatJennings, Environmental Engineer**~o..t ~**  DavidBays, Ph.D., Microbiologist 

# oOJl Risk Assessment and Science Support Branch (R.JXSSB) Antimicrobials Division (7510P)

Steven Weiss, Acting Branch Chief 

# %**Ct/ ~**  DonnaRandall, M.S. Ecological Risk Assessment Team Leader Risk Assessment and Science Support Branch (RASSB) Antimicrobials Division (751OP)
Seiichi Murasaki, Chemical Review Manager Regulatory Management Branch II Antimicrobials Division (751OP)

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### Responses to Central Valley Regional Water Quality ControlBoard's 60-Day Public Comments on the Registration Review PreliminaryWorkPlanfor PBSM.

Staffofthe Central Valley Regional Water Quality Control Board (Central Valley WaterBoard) has the following comments on the registration review preliminary work plan for perboric acid.


### 1. Comment: We are writing to encourageEPA to conduct an environmental risk assessment for perboric acid, and provide information tojustifythis recommendation. Our main comment is that while there may not be any waterbodies impaired due to perboric acid specifically, there are many waterbodies impaired due to boron and sodium, which are the main components ofperboric acid, sodium salt, monohydrate (PBSM). As noted in the work plan summary and the Environmental Fate and Effects Division scoping document for PBSM, perboric acid is very reactive and quickly breaks down into hydrogen peroxide, borate, boric acid and sodium. Thus, these are the appropriate constituents to examine for water quality risk assessment instead ofthe parent compound. 

### Agency's Response: The Agency will perform an ecological risk assessment for degradates ofPBSM that may enter surface water as a result ofits use as a laundry sanitizer.


### 2. Comment: InCalifornia there are 31 waterbodies that are impaired due to high concentrations ofboron. The 2008-2010 Clean Water Act Section 303(d) list for California contains 15 stream segments in the Central Valley, 11 segments in the Central Coastregion, 4 segments in the Los Angeles region, and 1 segment in the Lahontan region that exceed water quality standards for boron. Only4 ofthe total 31 water bodies impaired for boron statewide currentlyhave a total maximum daily load (TMDL) in place. There are also 38 listings for sodium and an additional155 listings for other salinity-related impairments in California

. Considering these listings, the statementthat boron and sodium "are not considered as stressors" seems to be an inadequate environmental risk assessment ofthese constituents. Documentation for the specific 303(d) listings is available at http://www.waterboards.ca.gov/water issues/programs/tmdl/integrated201 O.shtml 

### Agency's Response: TheAgency will revise the Antimicrobials Division's work plan summary dated March 2012 and the scoping document for PBSM, dated February 15, 2012, to reflect informationthat the Central Valley Regional Water Quality Control Board has provided regarding water bodies in California that are impaired due to high concentrations ofboron and sodium

. The Agency will also revise this document to acknowledge that, in spite ofboron's and sodium's natural occurrence and their function
as essential nutrients, boron and sodium can reach levels in surface waters from both anthropogenic and natural sources that can lead to impairment ofwater bodies. In addition, the Agency will remove any statements that indicate that boron and sodium are not considered to be stressors.

23. Comment: InCalifornia and the arid West, naturally occurring constituents like boron and salts can cause water quality impairments during low flow conditions or due to altered landscapes. Inthese cases naturally occurring compounds are considered environmental stressors. Meeting salinityrequirements, particularly for discharges to impaired waterbodies, is also often a challenge for publicly owned treatment works in the Central ValleyRegion. The Central Valley Water Board, and the dischargers we regulate, mustdirect considerable resources to our ongoing efforts to address the water quality impairments associated with boron and salinity. Priorto finalizing this registration review work plan and in future registration reviews for chemicals that contain or break down into these constituents, we encourage the US EPA to consider the environmental fate and ecological effects more deeply

. Inthis case, US EPA should specifically explore the potential significance ofdischarges to municipal wastewater treatment plants that discharge to boron and/or salinity impaired waters. Agency's Response: The Agency recognizes that use ofPBSM as a laundry sanitizer may potentially lead to the presence ofdegradates ofPBSM in surface waterbodies downstream ofdomestic wastewater treatmentplants that do not remove these degradates during wastewatertreatment. Therefore, we concur with the need to further explorethe potential significance ofreleases ofPBSM used as a laundry sanitizerto surface waters downstream ofdomestic wastewatertreatmentplants, including those surface water bodies with limited dilution and flow potential. The Agency will revise this work plan summary and scoping document to indicate that an ecological risk assessment ofdownthe-drain releases ofPBSM from use as a laundry sanitizerwill be performed and will include a list withjustifications ofenvironmental fate and ecological effects data requirements for degradates ofPBSM that will be needed to perform this assessment.

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