Karluss Thomas Senior Director UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460



## OCT 31 

## 2014

Silicones Environmental, Health, and Safety Center American Chemistry Council 7002nd StreetNE Washington, DC 20002
Re: DraftStudy Plan for 4 DirectDischarge Sites OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION

Testing Consent Orderfor Octamethylcyclotetrasiloxane (D4) CASRN: 556-67-2 40 C.F.R

. 799.5000 EPA-HQ-OPPT

-2012-0209
DearMr. Thomas: This letter is inresponse to your August 8,2014 letter subm itting a draft studyplanfor four direct discharge sites as identified intheApril4, 2014 Enforceable Consent Agreement (ECA) for Environmental Testing for Octamethylcyclotetrasiloxane (D4) between the U.S. Environmental ProtectionAgency and five manufacturers ofthe chemical. As youknow a complete Study Plan was due August2, 2014 (as perECAparagraph IX

.A, no more than 120 days after effectivedate), with a subsequent Quality Assurance Project Plan (QAPP) due October 1, 2014 (asperECA paragraph IX.A, no more than 180 days after effective date). The ECA specifiedthattesting would occurat four direct discharge sites and ten third partywaste water treatmentplants (WWTPs ). Whilethe Study Plan as submittedhas not fully fulfilledthe requirements ofthe ECA, the agency has some initial comments onthe Study Planthat are described below.



### 1. 

### GeneralProcess Description ofIndustrialPlantOperationsfor Each Site The ECA states (Appendix 1, page 20), "Ageneral process description ofthe industrialplant operations involvingD4 shall be provided. A more detailed description, including a written narrative andprocessflow diagram(s) ofthe wastewatertreatment system employed atthe sites shall also be provided (e.g., at a minimum consistentwithwhatwasprovided ineach facility's discharge permit application." The general process descriptionsprovided for the Momentive Performance Materials (MPM) Friendly (StudyPlan, section 9.2) and Waterford (Study Plan, section 10.2) sites are not

ln!ernet Address (URL) ·http//wwwepa gov RecyclediRecyclable • Pnnted With Vegetable 011 Based Inks on 100% Postconsumer Process Chlorine Free Recycled Paperadequate. These descriptions do not sufficiently describe the processes that contribute**D4~** containing wastewaters to the**on~site** WWTP. Thus, it is not clear how**D4~containing** wastewaters are generated at these sites. Additionally, the WWTP process flow diagrams (PFDs) provided for Wacker- Adrian (Study Plan, figure 7-2), MPM- Friendly (Study Plan, figure 9-2), and MPM- Waterford (Study Plan, figure 1**0~2)** are of a poor scan quality and are difficult to read. The PDFs cannot be adequately reviewed in their current visual quality. 2. Normal Operating Conditions The ECA (Appendices 1, 4, 5, 7 and 8) states, "Samples shall be collected during normal plant operations and during such times that effluent flow rates from the wastewater treatment system are representative of the normal plant operations." The ECA further states that, "the criteria or means that are used by the facilities to determine normal operating conditions will be documented in the**site~specific** Sampling Plans." The Study Plan includes a discussion of normal operating conditions for each of the four direct discharge sites and establishes that ERM will verify that the WWTPs are functioning under normal operating conditions and flow rates prior to sampling (sections 7.2.3, 8.2.3, 9.2.3, and 10.2.3). Although these parameters are important, greater detail is needed. Specifically, process equipment that feeds D4 containing wastes to the WWTP should also be operating under normal conditions as well. This point is made by the MPM- Waterford site (Study Plan, section 10.2.3) and should also be included in the respective sections for the

other three direct discharge sites.

The WWTP process flow diagrams provided for Wacker- Adrian (figure**7~2),** MPMFriendly (figure**9~2),** and MPM- Waterford (figure**10~2)** are of a poor scan quality and are difficult to read. The PDFs cannot be adequately reviewed in their current visual quality. 3. Site Characterization Sections 10.1 and 10.2 (regarding MPM- Waterford) of the draft Study Plan make some statements that require further clarification: a. Section 10.1 states that Outfall 020 is on the Hudson River's east bank. However, it appears that the outfall is on the west bank based on Figure 1**0~** 1. b. Section 10.2.2 makes reference to Outfalls 021 and 022, but makes no mention of Outfall 020 (the outfall to be sampled). It is unclear if the references to Outfalls 021 and 022 are correct, or if one of these outfall numbers should be 020. 2

### 4. Sampling Point

a. The ECA requiresthat surface water, sediment and biota sampling locations shall be collected as close as reasonably possible to the effluent outfall provided adequate mixing ofthe discharge andreceiving water has occurred (Appendix 8). SEHSC in its Study Plan has noted problems with establishing adequate mixing at some facilities and proposed using 100mas the sampling location. Please revise textto include the rationale for how the proposed approach satisfies the requirements ofthe ECA. b. Alternatively, at sites where adequate mixing cannotbe established EPAwould consider an approach where 3 required samples could be collected incrementallydownstream of the outfall (e.g., at 100m, 500 m and 1000 m) instead ofat a single location at lOOm. This approach maybracketthe pointwhere adequate mixinghas occurred.

c. With respect to the remaining sites, EPA expects that sampling locations are to be determined by establishing the point where adequate mixinghas occurred. The defined mixing zone withinthe NPDES permit orby calculating the size ofthe mixing zone with an EPA approved method may be useful methods to establish adequate mixing. One problem 

### with removing the use ofthe mixing zone methodology based on the four direct discharge sites in the program is thatthe full set ofsampling sites is not yet known. Given thatthe Hudson and Ohio Rivers likely will be the largestrivers in the samplingplan, 

### it may be premature to decide that the mixing zone technique is broadly inapplicable. Ifthe other water bodies are more in line with the River Raisin site (Adrian, MI) thenthe distance to complete mixing may be useful for the following ten sites. d. The Study Plan (section 7.2.2) statesthatthe effluent is discharged via outfall to a wetlands zonethat conveys the waste waterto the RiverRaisin. This is likely an unusual circumstance and consideration should be given to measuring the sediment concentrations inthe affected wetlands. Ifthere are releases of

### 04, a significantportion may be retained in this wetland environment. EPA recognizes thatthis would notbe how the Parties have typically conceptualized the monitoring location specified by the ECA but would likely generate more useful exposure assessment information. See photograph 4 in Figure 7-6 for more details. 

### 5. Biota Collection

a. The ECA (Appendix 8, page 48) states, "Biota sampled shall include benthic species collected in sediment ofthe receiving waterbody and two species offish, ifpracticable, ofdifferenttrophic guilds, inthe receiving water body." In the submitted material it is not apparent that this will be apriority as abundance is repeatedly listed as a criterion for fish sample collection. However, it is not necessary to collect a significantnumberoflarger fish to have sufficienttissue mass for analysis. Once the threshold for mass oftissue required for analytical needs has been met, the goal ofcollecting fish from two different trophic levels should supersede the abundance criterion in all sections ofthe sampling plan (for each site), in the standard operatingprocedures and inthe QAPP.



### 3b. The collection of benthic invertebrates should avoid species such as mussels, clams or crayfish to provide consistency across sites in the program due to identified differences in collection permits. 6. Omissions or errors in the submitted documents a. Study Plan section 2.2.Table 2-1 is listed as having the contact information for the signatory companies. Table 2-1 was not include with the submission. b. Study Plan section 3.1, Table 3-1 is listed as having a list of personal-care products that can be used by the samplers, but table 3-1 does not contain that information. c. Include a copy of the NPDES permits for all sites in the program. d. Study Plan sections 7.4 & 8.4, the literature sources for the fish species that may be present need to be identified for the Adrian, MI and East Carrollton, KY sites. Currently "a review of various literature sources" or "the results of a 2008 biological study" are the only references. The literature sources should be identified and added to the references

list. EPA asks the Signatory Companies to continue its efforts to secure the cooperation of third party WWTP operators, as well as to continue to work with EPA to find a path forward to address the WWTP issue. If you have any questions, please contact Heather Njo of my staff at 202-564-2574 or at njo.heather@epa.gov. Sincerely, Wendy Cleland-Hamnett, Director Office of Pollution Prevention and Toxics 4