### Via Electronic Mail and Certified Mail

January 31, 2012

Maria J. Doa, Ph.D.

Director
Chemical Control Division

Office of Pollution Prevention and Toxics

U.S. Environmental Protection Agency 1200 Pennsylvania Ave., NW Washington, DC 20460

Re: Development of Environmental Monitoring Proposal for Certain Cyclic Siloxanes

Dear Dr. Doa:

On behalf of certain member companies 1 

### of the Silicones Environmental, Health and Safety Council of

No rth America (SEHSC) 2 

### , we are writing to follow

- up on our review and discussions of your September 19, 2011 letter with attachments (September 19 th 

### Letter), which responded to the Draft Proposal for Ecotoxicity Testing and Environmental Monitoring with Cert ain Cyclic Siloxanes that we submitted to the U.S. Environmental Protection Agency (EPA) on April 29, 2011 (Initial Draft Proposal). As discussed more fully below, SEHSC has completed Conceptual Site Models (CSMs), which are now being used to develop a re vised Enforceable Consent Agreement (ECA) proposal that we think will respond to EPA’s desires in a reasonable and practical manner.

After receiving the September 19 th 

### Letter, SEHSC met with EPA staff on October 13 and October 27 and by teleconference o n November 10, 2011

, to discuss and clarify EPA’s comments on the Initial Draft Proposal. During and since these discussions, SEHSC has been actively engaged in efforts to comprehensively address the issues EPA noted so as to inform the development of a r evised environmental monitoring proposal. Attachment 1 to this letter provides a detailed description of the work performed, its implications, and the proposed conceptual elements of an environmental monitoring program. It also outlines the work currentl y underway, the completion of which will enable us to submit to EPA a refined ECA proposal.

1 Bluestar Silicones USA Corporation; Dow Corning Corporation; Evonik Goldschmidt Corporation; Momentive Performance

Materials Inc.; Shin

- Etsu Silicones of America, Inc.; and Wacker Chemical Corporation.

2 SEHSC is a not

- for

- profit trade association comprised of North American silicone chemical producers and importers. For

more than 30 years, SEHS C has promoted the safe use of silicones through product stewardship and environmental, health

and safety research. A primary focus of SEHSC is to coordinate scientific research on health, safety and environmental

issues involving silicones.Maria J. Doa, Ph.D. US Environmental Protection Agency January 31, 2012 Page 2 of 3



### As documented in Attachments 1 and 2, SEHSC member companies have expended considerable resources to generate D 4 

### and D 5 

### facility release data for each of thirtee n sites. 3 

### SEHSC engaged Environmental Resource Management (ERM), an environmental consulting firm (Consultant), to aggregate these data and compile summary statistics and mass balances by facility type ( i.e.

, manufacturer, formulator, or processor). The collection and aggregation of these data represent a substantial effort over a short period of time and, more importantly, provide valuable new information regarding the release profile of representative D 4 

### and D 5 

### manufacturing, processing, and formulating (MPF) facilities.

The Consultant used the aggregated facility release data to develop a generic CSM for Member Company D 4 

### and D 5 

### MPF facilities. In addition, the Consultant prepared a generic CSM for Municipal Wastewater Treatment Plants (WWTPs). Tog ether, these CSMs provide for a reasonable understanding of D 4 

### and D 5 

### releases from MPF facilities and WWTPs, the resulting exposure pathways, and potential receptors. The CSMs demonstrate that the appropriate conceptual elements of a D 4 

### and

D 5 

### environmen tal monitoring program would include a focus on the aquatic environment and could

include releases from WWTP as well as those from D 4 

### and D 5 

### MPF facilities that discharge effluent directly to surface waters.

Importantly, the Global Silicones Industry ha s an ongoing environmental stewardship program to monitor the presence of D 4 

### and D 5 

### in a number of international locations, including in the United States. This program encompasses the monitoring of D 4 

### and D 5 

### in the influent, effluent, and sludge of WWTPs and the monitoring of D 4 

### and D 5 

### in surface sediment and aquatic biota potentially impacted by releases from nearby facilities. Based on the CSMs, it appears that augmenting this voluntary program by extending key elements to a domestic U.S. monitoring pr ogram to include additional municipal WWTP sites and SEHSC Member Company facilities that directly discharge effluent to surface waters could provide a principled and scientifically sound means to generate a robust dataset for assessing the potential envir onmental impacts of these substances.

SEHSC is continuing to work with a Consultant to develop the substantive elements of a revised ECA proposal that is both grounded in sound science and that takes into account the existing data and data collection efforts relating to these substances. Addi tional tasks that are on

- going include the development of the scientific rationale for augmenting the international environmental stewardship program by extending key elements to a domestic U.S. monitoring program with additional sites, the

identification of specific WWTP sites in the U.S. for monitoring based on the CSM and additional modeling, and confirmation of end points, number of samples, and frequency/duration of sampling for monitoring locations. The completion of these tasks will enable us to pro vide EPA with a revised ECA Proposal that contains a level of specificity which is intended to not only help facilitate EPA’s consideration of the proposal, but also provide the participating Member Companies with an appropriate level of certainty regardin g the potential scope of the program which they will be agreeing to propose.

3 Our Initial Draft Proposal identified fourteen sites under the direct control of participating SEHSC member companies that

were engaged in D 4 /D 5 manufacturing, processing, or formulating activities. Upon further review, it has been determined

that one of those sites should not have been included as it does not manufacture, process, or formulate with D 4 or D 5 . A

revised list is provided in Attachment 3 which also reflects updates to the “facility description” for certain locations base d

on revised information concern ing D 4 , D 5 activities at those sites.Maria J. Doa, Ph.D. US Environmental Protection Agency January 31, 2012 Page 3 of 3



### We are working to complete these tasks as quickly as possible and will keep you informed of our progress. In the meantime, we welcome the opportunity to meet with you and your staff to discuss the work performed to date and our proposed approach. We will follow up with you in this regard. Should you have any questions or concerns, please do not hesitate to contact me.

Sincerely,

Karluss Thomas

Executive Director

Enclosures

Attachment 1

– Description of Work Performed, Implications, On

- going Work

Attachment 2

– D 4 

### and D 5 

### Conceptual Site Models and Mass Balance Report

Attachment 3

– Table of SEHSC Member Company D 4 

### /D 5 

### Manufacturing, Processing, and Formulating

F acilities in the U.S.

# Attachment 1 Description of Work Performed, Implications, On

- going WorkSilicones Environmental, Health and Safety Council January 31, 2012 

### ATTACHMENT 1

In communications to the Silicones Environmental, Health and Safety Council (SEHSC),

including in the September 19, 2011 letter with attachment (September 19 th 

### Letter), the U.S.

Environmental Protection Agency (EPA) has indicated that the pur pose of a D 4 

### and D 5 

### environmental monitoring program would be to develop a better understanding of the sources of

and pathways to the potential environmental concentrations of D 4 

### /D 5 

### in environmental media

and biota associated with industrial releases from manufacturing, processing, formulating (MPF)

and high volume industrial or commercial end users of D 4 

### and D 5 

### . In the September 19 th 

### L etter,

EPA outlined a four

- phase approach to such a program, which included the development of

Conceptual Site Models (CSM s) at the outset for MPF facilities and municipal wastewater

treatment plants (WWTPs). EPA indicated that these CSMs would be used to determine

appropriate media types and sampling locations and to otherwise inform the preparation of a

detailed sampling p lan.

Bearing this in mind, SEHSC member companies have been actively engaged over the past

several months to develop a revised proposal that appropriately addresses EPA’s concerns in

light of available information. This document summarizes the wor k SEHSC member companies

have performed with respect to the design and development of a revised environmental

monitoring proposal for consideration by EPA. In particular, it describes the specific tasks

completed and their implications, proposed conceptua l elements/approach for a D 4 

### /D 5


### environmental monitoring program, and on

- going work.

Description of Work Performed and Implications

1 . Member Company Survey

- Data Collection on Material Throughput and Releases at MPF

Sites.

To facilitate the prepara tion of CSMs for MPF facilities, six SEHSC member companies

participated in a survey regarding D 4 

### and D 5 

### throughput and estimated releases at their D 4 

### /D 5 

### MPF facilities. A list of participating companies and facilities is provided in Attachment 3.

Partic ipating companies provided worksheets containing confidential business information (CBI)

on a total of thirteen MPF facilities to SEHSC for processing (due to CBI concerns worksheets

submitted by each company were not shared with the other member companies ). RespondentsSilicones Environmental, Health and Safety Council January 31, 2012 

### provided information on D 4 

### /D 5 

### input and output streams for each site using a standard template

with reference to a generic block flow diagram. For sites engaged in multiple activities ( e.g.

, both processing and formulating), input/outputs with respect to a particular activity were

reported separately, as appropriate.

Member companies committed significant internal and external resources to generate the data

needed to participate in this survey in the given timeline. This considerable ef fort resulted in the

collection of detailed information on two manufacturing, seven formulating, and nine processing

facilities (corresponding to the D 4 

### /D 5 

### MPF facilities under the direct control of the participating

SEHSC member companies). As discussed further below, SEHSC engaged Environmental

Resources Management (ERM), an environmental consulting firm (Consultant), to process and

analyze these data.

2. Data Analysis

- Aggregation, Preparation of Summary Statistics, Mass Balances, and CSMs

SEH SC’s Consultant reviewed the facility worksheets supplied by the SEHSC member

companies, aggregated the data, and prepared summary statistics on each input/output stream.

Mass balances and corresponding block flow diagrams showing representative input/out put

amounts were prepared for each facility

- type for which sufficient data were available. No mass

balances or summary statistics are provided for D 4 

### /D 5 

### manufacturing or D 4 

### formulating due to

confidentiality issues as fewer than three companies could prov ide relevant data. However, to

provide EPA with a profile of manufacturing sites, the two companies engaged in D 4 

### /D 5 

### manufacturing each intend to provide confidential facility input/output stream data to EPA under

separate cover so that these highly sensi tive data may be accorded appropriate CBI protection.

The Consultant’s Report, which contains a description and analysis of the data and relevant

tables and figures, is provided in Attachment 2.

The Consultant also used the data obtained in the member company survey and available fate

and transport information for D 4 

### and D 5 

### to prepare a generic CSM for human and ecological

receptors for D 4 

### /D 5 

### MPF facilities, which is shown in Figure 6 of Attachment 2. The Consultant

determined that a single, generic CSM for human and ecological receptors would appropriately

represent both D 4 

### and D 5 

### and all facility types. A complete description of the CSM and its

underlying scientific basis is provided in Section 3.0 of the Consultant’s Report in Attachment 2.Silicones Environmental, Health and Safety Council January 31, 2012 

### As described in the Consultant’s Report, although a wide range of potential pathways for D 4 

### and

D 5 

### are depicted in the CSM, the only exposure pathways deemed potentially complete for D 4



### and D 5 

### ( i.e. , pathways that lead to a reasonable expectation of po tential exposure to humans or

the environment) are:

**•** inhalation exposure resulting from dispersion in air (this pathway applies only to human

receptors, because ecological receptors are not typically evaluated for inhalation

exposure risk); and

**•** exposur es via sediment, including direct exposure for bottom

- dwelling biota and indirect

exposure via the food chain to ecological receptors.

The Consultant also prepared a generic CSM for human and ecological receptors for municipal

WWTPs based on a considerati on of types of units, releases, and site characteristics associated

with municipal WWTPs. This CSM is shown in Figure 11 of Attachment 2. A complete

description of the generic CSM for municipal WWTPs and its underlying scientific basis is

provided in Sec tion 5.0 of the Consultant’s Report in Attachment 2.

The generic CSM for municipal WWTPs also shows a wide range of potential pathways for D 4



### and D 5 

### , but only air for human receptors and sediment for ecological receptors are considered

to be complete path ways based on the characteristics of the materials and available

information.

As highlighted below, these findings are significant with respect to the design of an

environmental monitoring program.

Conceptual Elements of Environmental Monitoring Progr am

Based on an evaluation of the MPF and municipal WWTP CSMs , an appropriate focus of an

environmental monitoring program would be on relevant media for MPF sites that directly

discharge effluent to surface waters (4 sites in total, as show in Attachment 3 ) and on municipal

WWTPs whose effluent would reflect inputs from industrial sites that process or formulate with

D 4 

### or D 5 

### and/or dispersive (consumer) uses (number of sites to be determined, as noted in the

discussion of On

- going Activities, below).Silicones Environmental, Health and Safety Council January 31, 2012 

### Fi nal design of the proposed environmental monitoring program will entail a careful evaluation of

the CSMs. Pathways of migration are clearly diagrammed in the CSMs for human and

ecological receptors and will form the basis for selection of media sampling t ypes and locations

at each facility identified for monitoring. In addition, data available as a part of the on

- going

global monitoring program the Silicone Industry originally initiated in the 1990s on D 4 

### in effluents

and a robust program initiated in 200 9 to understand the actual fate and effects of cVMS in the

environment will help inform the basis of a proposed monitoring plan.

With respect to the air pathway, although hypothetically a complete pathway, it is not relevant to

a proposed environmenta l monitoring program. Inhalation exposure resulting from dispersion in

air applies only to human receptors as ecological receptors are not typically evaluated for

inhalation exposure risk. Also, the environmental fate and transport in air of volatile

met hylsiloxanes such as D 4 

### , and D 5 

### have been thoroughly investigated in modeling

assessments, and laboratory and field studies. The results of those studies are summarized

below:

**•** Volatile methylsiloxanes such as D 4 

### and D 5 

### have a unique combination of

physico chemical properties: relatively high volatility (like small alkanes), high air/water

partition coefficients, medium to low octanol/air partition coefficients and relatively short

half

- lives (6~10 days) in air. Based on modeling calculations, once release d to the

environment, the majority of D 4 

### and D 5 

### will be distributed in the air; greater than > 98% of

all the emitted methylsiloxanes will be degraded in the atmosphere; >90% degradation

occurred in the atmosphere over the source regions (Xu and Wania, 201 1).

**•** Based on an assessment with the OECD overall persistence and LRTP screening tool (v

2.1) and the GloboPOP model, D 4 

### and D 5 

### can travel a long distance in air, but only a

small fraction (< 9 %) of the emitted total may be circulated in the air outside o f the

source regions (Xu and Wania, 2011). The airborne D 4 

### and D 5 

### tend to stay in the air and

exhibit a very small potential to deposit back to the ground or waterways (Xu and Wania,

2011).

**•** Ambient air monitoring data generally agree with the above model ing assessments,

including the concentrations measured in rural and remote regions (McLachlan et al,

2010; Genualdi et al., 2010).

**•** The existing monitoring data of the surface media in remote regions are also consistent

with the lack of deposition of vola tile methylsiloxanes as summarized in a recentSilicones Environmental, Health and Safety Council January 31, 2012 

### document by Environment Canada (Environment Canada, 2011, D5 Board of Review

“Ringtail” Document 232). For example, D 4 

### and D 5 

### can be easily detected in sediment

near the points of release, but D 4 

### and D 5 

### above the detection limits cannot be found in

remote sediments, including the samples from the cold arctic regions (Evenset, 2009;

Campbell, 2010). For biota, D 4 

### and D 5 

### were again not detectable in most fish samples

collected in the remote regions that have no local route of exposure (Warner et al, 2010).

The above information shows that, although D 4 

### and D 5 

### are released to air from both MPF

facilities and Municipal WWTPs, the deposition of airborne D 4 

### and D 5 

### to surface media is

estimated to be very small due t o the unique combination of physicochemical properties of

these chemicals. As concluded by an Independent Expert Scientific Panel (Canadian D5 Board

of Review) “an important aspect of the environmental fate of Siloxane D5 is that the

compartment into whic h it is most released and most likely to occur is also the compartment

where it undergoes the most rapid rate of transformation.” For these reasons, the release to air

will not lead to exposure of ecological receptors and, therefore, it is not anticipated to be part of

a revised proposed environmental monitoring program.

On

- G oing Activities

SEHSC member companies are engaged in a number of on

- going activities designed to inform

the preparation of a revised D 4 

### /D 5 

### environmental monitoring proposal. Thes e activities include

working with a Consultant to identify specific WWTP sites in the U.S. for monitoring based on

the CSM and additional modeling analyses; confirmation of end points, number of samples, and

frequency/duration of sampling for monitoring lo cations; and the development of scientific

rationale for augmenting the Silicones Industry international environmental stewardship program

by extending key elements to a domestic U.S. monitoring program with additional sites.

1. Identification of Speci fic Sampling Locations, Media

SEHSC’s Consultant has also been tasked with assisting in the development of a potential

D 4 

### /D 5 

### environmental monitoring program through the identification of specific municipal WWTPs

for inclusion in the program based on a c onsideration of relevant key variables, potentially

including location of indirect discharge MPF facilities, population served by the WWTP, andSilicones Environmental, Health and Safety Council January 31, 2012 

### plant characteristics ( e.g. , treatment type, size, rural vs. urban, watershed and geographic

location in the U.S

., etc. ). This work is on

- going.

Other parameters will also be considered in the final selection of sites after evaluation of the

relevant data, including WWTP monitoring programs/data for D 4 

### and D 5 

### that are ongoing. For

example, WWTP data have alread y been reported by Environment Canada (EC) and the

Oregon Department of Environmental Quality (OR DEQ). Both EC and OR DEQ have included

a variety of WWTP/POTW sites that take into consideration both dispersive uses from

populations of different sizes and /or industrial discharge. In Canada, the dataset demonstrates

a high removal efficiency by all WWTP types, with the possible exception of non

- aerated

lagoons. All types of WWTPs (tertiary, secondary, and aerated lagoons) have D 4 

### /D 5 

### removal

efficiencies i n excess of 97%. The efficiency of non

- aerated primary treatment lagoons was

estimated at 92%. The OR DEQ initiated a WWTP monitoring program in 2010 which required

52 major facilities to analyze their effluent for D 4 

### and D 5 

### . Analysis conducted to date f ound that

D4 and D5 levels were below the 7

- 16 ppb analytical levels of quantitation (LOQs) in all WWTP

effluent evaluated.

A determination of number of sites, frequency/duration of sampling, media, etc. will be provided

in the revised environmental monit oring proposal.

2. Augmenting Global Silicone Industry International Environmental Monitoring Program.

The Global Silicones Industry has an ongoing international environmental stewardship program

to monitor the presence of D 4 

### and D 5 

### in a number of int ernational locations

-- including one site

in the U.S. The purpose of this program is to enhance the understanding of the potential

contribution of D 4 

### and D 5 

### to the environment via the discharge of effluent into surface water,

which can result in exposure through sediment, including direct exposure for bottom

- dwelling

biota and indirect exposure via the food chain to ecological receptors.

Based on the CSMs, it appears that augmenting this voluntary program by extending key

elements to a domestic U.S. mon itoring program to include additional municipal WWTP sites

and SEHSC Member Company facilities that directly discharge effluent to surface waters could

provide a principled and scientifically sound means to generate a robust dataset for assessing

the poten tial environmental impacts of these substances.Silicones Environmental, Health and Safety Council January 31, 2012 

### For your reference, additional background on the international environmental stewardship

program is provided below. The program includes two key elements:

**•** The first element is the determination of represen tative concentrations of D 4 

### and D 5 

### in the wastewater stream (influent, effluent, and sludge) of municipal WWTPs. The

data will be used to estimate mass loadings of D 4 

### and D 5



### • The second element is long

- term monitoring for D 4 

### and D 5 

### in surface sediment and

aquatic biota ( marker fish and benthic species) at 4 sites globally with annual sample

collection to assess temporal trends in D 4 

### and D 5 

### concentrations in sediments and

biota near impacted areas. The goal of this project is to determine if concentrations

of D 4 

### and D 5 

### in sediment and aquatic biota are stable. to the local aquatic

environment and to detect any temporal trends associated with the mass loading.

Detailed project charters are in place for both of these key elements and are available if desired.

The proposed study areas

– as well as previously studied locations across the globe

-- including

Oslo (Norway), Tokyo Bay (Japan), Toronto, Ontario (Canada), and St. Paul, Minnesota (USA),

represent a broad cross section of environmental conditions.

W ith respect to the first element, analytical method development is completed for biosolids and

is near complete for influent/effluent (expected S1 2012). Adaptation of the Simple Treat model

is underway to handle all WWTP types and will be used to model t he behavior of D 4 

### and D 5 

### in

various types of WWTPs.

With respect to the long

- term monitoring element, the results of several modeling projects

suggest that measured concentrations in air, water, soils, and sediments, as well as in

organisms, will reflec t pseudo

- steady

- state (concentrations will change seasonally but are

largely a consequence of the current rate of emission). This was recently confirmed by an

independent Expert Scientific Panel (Canadian D5 Board of Review Report) as the Expert Panel

con cluded “The rate of accumulation of Siloxane D5 in air, water, soils, and sediments, as well

as in organisms, is determined by its rate of release to the environment and, once there, its

rates of movement to other compartments of the environment (dissipati on) and transformation.

Because Siloxane D5 has been used in commercial and industrial applications for a relativelySilicones Environmental, Health and Safety Council January 31, 2012 

### long time

– more than 30 years

– and, given its rates of dissipation and transformation in the

environment, current concentrations of Silox ane D5 are at a quasi

- steady

- state.”

Similarly, this means that measured concentrations in the top few centimeters of sediment are

likely to reflect a pseudo

- steady

- state as well, particularly in systems with high rates of net

sedimentation like Lake Pepi n (30 mm per year) and the coastal sediments of the Inner

Oslofjord (up to 9 mm per year). In systems with a lower rate of sediment deposition, such as

the deep basins of Lake Ontario, the sediment would probably need to be collected from the top

1

- 2 cm t o ensure that concentrations reflect the average rate of emission in the last 10 years.

The predicted behavior of D 4 

### and D 5 

### in three different aquatic systems has been investigated

using an established steady state model ( QWASI) . The three systems exam ined were the

Inner Oslofjord (Norway)

, Lake Ontario (North American Great Lakes) and Lake Pepin (a natural

shallow lake on the Mississippi river between Minnesota and Wisconsin, down

- stream of

Minneapolis

- St Paul. In all cases, models predict that concen trations in the top 5 cm of

sediment reach steady state concentration levels within 8 years. It follows that concentrations

measured in the surface layer of sediment will be reflective of current emission levels, since

emissions of D 4 

### and D 5 

### have not chang ed markedly in the last 10 to 15 years globally

. As

noted above, the goal of the project is to confirm whether concentrations of D 4 

### and D 5 

### in

surface sediment and aquatic biota are stable or changing (following a decreasing or increasing

trend).

This on going effort described above, combined with augmenting this program by extending key

elements to a domestic U.S. monitoring program to include additional municipal WWTPs in the

U.S. and the monitoring of releases of D 4 

### and D 5 

### from member company facilities with direct

discharges, would provide a robust dataset for understanding the potential contribution of D 4



### and D 5 

### to the environment via the discharge of effluent into surface water.

The details of sampling ( e.g. , minimum number of samples per location) and an analysis plan

for each specific site would need to be developed for inclusion in a revised Enforceable Consent

Agreement (ECA)

- related monitoring plan. However, a significant amount of work has already

been completed on analytical methods and QA/Q C for environmental monitoring of cyclic

siloxanes (Durham et al., 2009a and 2009b).Silicones Environmental, Health and Safety Council January 31, 2012 

### References

Canadian D5 Board of Review Report; Report of the Siloxane D5 Board of Review (PDF; 817KB) http://cdr

- siloxaned5

- bor.ca/default.asp?lang=En&n=60053180

- 1

Ca mpbell, R. 2010. A collaborative assessment of cyclic volatile methylsiloxanes (D4, D5, D6) concentrations in the Norwegian Environment. Final Report to Centre Europeen des Silicones(CES), European Chemical Industrial Council (CEFIC), Dow Corning HES Stud y No.

11061

- 108.

Canadian D5 Board of Review Report; Report of the Siloxane D5 Board of Review (PDF; 817KB) http://cdr

- siloxaned5

- bor.ca/default.asp?lang=En&n=60053180

- 1

Durham, J.A., Huff, D.W, McNett, D.A., Powell, D.E., Gerhards, R, and Boehmer, T. 2009. Development of a Robust Quality Control Program for Environmental Monitoring Studies with Cyclic Siloxanes, Poster presented at SETAC North America, 30 th


### Annual Meeting, 19

- 23 November 2009, New Orleans, Louisiana.

Durham, J.A., Huff, D.W, McNet t, D.A., Powell, D.E. 2009. Trace analytical method development enhanced by the use of 14C

- radiolabelled isotopes of octamethycyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6), Poster presented at SETAC Euro pe, 19 th 

### Annual Meeting, 31 May

– 4 June 2009, G ö teborg, Sweden.

Environmental Canada, 2011, Ecotoxicity and environmental occurrence of octamethylcyclotetrasiloxane (D4), decamethylpentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6)

- State of the S cience. D5 Board of Review “Ringtail”

Document 232.

Evenset, A.; Leknes, H.; Christensen, G.; Warner, N. A.; Remberger, M.; Gabrielsen, G. W. 2009. Screening of new contaminants in samples from the Norwegian Arctic. SFT Report 1049/2009 (TA

- 2510/2009 ). Oslo (NO): Norwegian Pollution Control Authority (SFT), Akvaplan

niva, Norwegian Polar Institute and Norwegian Institute for Air research (NILU).

Genualdi, S., Harner, T. Cheng, Y., MacLeod, M., Hansen, K. M., van Egmond, R.; Shoeib, M., Lee, S. C., 20 11. Global distribution of linear and cyclic volatile methyl siloxanes in air. Environ. Sci. Technol. 45, 3349

- 3354.

McLachlan, M. S., Kierkegaard, A., Hansen, K. M., Van Egmond, R., Christensen, J. H., Skjøth, C. A., 2010. Concentrations and fate of deca methylcyclopentasiloxane (D5) in the atmosphere. Environ. Sci. Technol. 2010, 44, 5365

- 5370.

Warner, N. A.; Evenset, A.; Christensen, G.; Gabrielsen, G. W.; Borga, K.; Leknes, H. 2010. Volatile siloxanes in the European Arctic: Assessment of the sourc es and spatial distribution.
Environ. Sci. Tecnol . 44, 7705

- 7710.

Xu, S.; Wania, F. 2011. Chemical Fate, Latitudinal Distribution and Long

- Range Transport of Cyclic Volatile Methylsiloxanes in the Global Environment: A Modeling Assessment. Chemosphere. 2011 (In Press).

# Attachment 2

D 4 

# and D 5 

# Conceptual Site Models and Mass Balance Report

# FINAL

Delivering sustainable solutions in a more competitive world 

# D 4 

# and D 5 

# Conceptual Site

Models and Mass Balance Report

Silicones Environmental, Health and Safety Council Herndon, VA 20171

January 2012

www.erm.com

# FINAL

Silicones Environmental, Health and Safety Council



# D 4 

# and D 5 

# Conceptual Site

Models and Mass Balance Report

January 2012

ERM Project No. 0151161



### Salvatore T. Giolando, Ph.D. Partner-in-Charge

Steve Peterson, Ph.D., Technical Director

Elsie F. Millano, Ph.D., P.E., Project Manager

Environmental Resources Management
1701 Golf Road, Suite 1-1000 Rolling Meadows, IL 60008

www.erm.comFINAL

ERM 

### iii January 2012 

### TABLE OF CONTENTS

EXECUTIVE SUMMARY.............................................................................................VII

1.0 INTRODUCTION.................................................................................................1

2.0 FATE AND TRANSPORT INFORMATION ....................................................3

3.0 CONCEPTUAL SITE MODEL FOR D 4 

### AND D 5 

### INDUSTRIES....................6

3.1 GENERIC BLOCK FLOW DIAGRAM TEMPLATES .........................6

3.1.1 Manufacturer Block Flow Diagram Description.......................6

3.1.2 Formulator Block Flow Diagram Description...........................7

3.1.3 Processor Block Flow Diagrams Description ............................8

3.1.4 Basis for a Single CSM for All Types of Facilities ....................9

3.2 GENERIC D 4 

### AND D 5 

### INDUSTRIAL CSM FOR HUMAN AND

ECOLOGICAL RECEPTORS .................................................................9

3.2.1 Procedures..................................................................................9

3.2.2 Air Pathways ...........................................................................10

3.2.3 Surface Soil ..............................................................................11

3.2.4 Surface Water ..........................................................................11

3.2.5 Sediments.................................................................................12

3.2.6 Landfills to Air and Ground Water.........................................12

3.2.7 Summary..................................................................................12

4.0 MASS BALANCE DATA AGGREGATION....................................................13

4.1 PROCEDURES........................................................................................13

4.2 MASS BALANCE DATA AGGREGATION RESULTS .....................14

4.2.1 Manufacturers Data Observations..........................................14

4.2.2 Formulators Data Aggr egation Observations.........................14

4.2.3 Processors Data Aggregation Observations............................15

5.0 GENERIC POTW CSM ......................................................................................17

5.1 GENERAL TREATMENT REQUIREMENTS.....................................17

5.2 POTW POTENTIAL TREATMENT TECHNOLOGIES....................17

5.3 POTENTIAL EFFECTS OF POTW TREATMENT

TECHNOLOGIES ON THE FATE AND TRANSPORT OF D 4 

### OR

D 5 

### ...............................................................................................................18

5.4 DESCRIPTION OF THE “TYPICAL” POTW ....................................19FINAL

ERM 

### iv January 2012 

### 5.5 GENERIC CSM FOR HUMAN AND ECOLOGICAL RECEPTORS

FOR POTWS RECEIVING WASTEWATER CONTAINING D 4 

### OR

D 5 

### ...............................................................................................................21

6.0 CONCLUSIONS..................................................................................................22

LIST OF TABLES

Table 1 Member Company Facilities that Reported Data

Table 2 Summary of Data Aggregation before Mass Balance for

Formulators

Table 3 Mass Balance for Formulators of D 5



### Table 4 Summary of Data Aggregation before Mass Balance for

Processors

Table 5 Mass Balance for Processors

Table 6 Potential Technologies and Disposal Options for Publicly

Owned Treatment Works

LIST OF FIGURES

Figure 1 Block Flow Diagram Te mplate for Manufacturers of D 4 

### or

D 5



### Figure 2 Block Flow Diagram Template for Formulators of D 4 

### or D 5



### Figure 3 Block Flow Diagram Template for Processors of D 4 

### or D 5 

### with On-site Wastewater Treatment Plant

Figure 4 Block Flow Diagram Template for Processors of D 4 

### or D 5 

### without On-site Wastewater Treatment Plant

Figure 5 Block Flow Diagram Template for Processors of D 4 

### or D 5 

### with On-site and Off-site Wastewater Treatment Plants

Figure 6 Generic D 4 

### and D 5 

### Industrial Conceptual Site Model for Human and Ecological Receptors

Figure 7 Mass Balance for Formulators of D 5



### Figure 8 Mass Balance for Processors of D 4FINAL

ERM 

### v January 2012 

### Figure 9 Mass Balance for Processors of D 5



### Figure 10 Generic Block Flow Diagram for POTWs Receiving Wastewater Containing D 4 

### or D 5



### Figure 11 Generic Conceptual Site Model for Human and Ecological Receptors for POTWs Receiving Wastewater Containing D 4 

### or D 5FINAL

ERM 

### vi January 2012 

### LIST OF ACRONYMS

CSM Conceptual Site Model

ERM Environmental Resources Management, Inc.

D 4 

### Octamethylcyclotetrasiloxane

D 5 

### Decamethylcyclopentasiloxane

NESHAP National Emission Standards for Hazardous Air

Pollutants NPDES National Pollutant Discharge Elimination System OSHA Occupational Safety and Health Administration POTW Publicly Owned Treatment Works SEHSC Silicones Environmental, Health and Safety Council USEPA United States Environmental Protection Agency

WEF Water Environment Federation

WWTP Wastewater Treatment PlantFINAL

ERM 

### vii January 2012 

### EXECUTIVE SUMMARY

Environmental Resources Management (ERM) was retained by the

Silicones Environmental Health and Safety Council (SEHSC) to evaluate facility emissions and throughput data provided by six companies that are members of SEHSC (Member Companies) to develop two work products:

 

### Generic aggregate Conceptual Site Models (CSMs) for facilities in the United States, including manufactur ers, formulators, and processors

of D 4 

### and D 5 

### ; and

 

### Mass balances for formulators of D 5 

### and for processors of D 4 

### and D 5



### . No mass balances for manufacturers of D 4 

### and D 5 

### and formulators of

D 4 

### are provided due to business confidentiality concerns (fewer than three Member Companies provided data).

ERM developed CSMs based on standard practices for risk assessment. 1,2,3



### In addition, the SEHSC tasked ERM with developing a generic CSM for publicly owned treatment works (POTWs) that receive wastewater containing D 4 

### and/or D 5 

### (the “POTW CSM”). A generic block diagram was prepared for a typical mid- to sm all-size POTW, with the assumption that it had only (1) primary and se condary treatment (activated sludge) and effluent chlorination for the liquid waste before discharge to a surface water body, and blending and storage, anaerobic digestion, and storage for the sludge produced during primary and secondary treatment (“biosolids”), followed by beneficial use of the biosolids as a fertilizer or

soil amendment.

Based on the evaluation presented in this report, ERM concluded the following for the industrial facilities:

 

### Aggregation of all facilities for the generic conceptual site model with arithmetic weighted averages of the emissions for the different types of facilities provide a useful summary of the potential fate, transport, and exposure pathways for these substances in the environment.

1 USEPA (2001). Risk Assessment Technical Background Document for the Paint and Coatings Hazardous Waste Listing Determination

.
2 USEPA (1996). Attachment A in Soil Screening Guidance: User’s Guide , EPA/540/R-96/018.

3 USEPA (1988). Guidance for Conducting Remedial Invest igations and Feasibility Studies under CERCLA

, EPA/540/G-89/004.FINAL

ERM 

### viii January 2012  

### The greatest emissions of D 4 

### and D 5 

### are those to air, given that the solid waste or waste from operation streams sent off-site for disposal are typically thermally treated, which treatment would destroy most,
if not all, D 4 

### and D 5 

### in those waste streams..

After assessing the chemical and physic al properties of D4 and D5 and the potential sources and pathways of exposure to human and ecological receptors, ERM concluded that the following two pathways were potentially complete for both the gene ric industrial facility and the generic

POTW:

 

### Inhalation exposure resulting from dispersion in air (this pathway applies only to human receptors, because ecological receptors are not typically evaluated for inhalation exposure risk).

 

### Exposures via sediment, includin g direct exposure for bottomdwelling biota and indirect exposure via the food chain to ecological

receptors.FINAL

ERM 

### 1 January 2012 

### 1.0 INTRODUCTION

Octamethylcyclotetrasiloxane (D 4 

### ) and decamethylcyclopentasiloxane (D 5 

### ) are chemical products from the broader family of polydimethylsiloxanes (PDMSs) that have a wide range of industrial and consumer applications

in the United States and internationa lly. Both of these substances are manufactured, formulated and/or processed at a number of sites in the

United States. The Silicones Enviro nmental, Health and Safety Council (SEHSC) retained Environmental Reso urces Management, Inc. (ERM) to prepare the following work products:

 

### The generic conceptual site model (CSM) and mass balances presented herein for industrial facilities; and

 

### A block flow diagram and CSM for publicly owned treatment works (POTWs) for use in the evaluation of emissions from POTWs receiving D 4 

### and/or D 5



### .

To complete the industrial CSM, ERM was tasked with reviewing Business Confidential worksheets prov ided by six of the SEHSC member companies with input and output da ta for three types of facilities (manufacturers 4 

### , formulators 5 

### , and processors 6 

### ). Data were received from six Member Companies regarding 13 distinct facilities, including two sites engaged in manufacturing, seven in fo rmulating, and nine in processing activities -- see Table 1 (some facilities engaged in more than one activity). It is important to note that D 4 

### and D 5 

### are sold to numerous other downstream formulators and processors in significant quantities. This report does not include data from those downstream customers.

The remainder of this report is organized as follows:

 

### Section 2.0: Presents relevant ch emical, physical, and environmental fate and transport properties of D 4 

### and D 5 

### ;

 

### Section 3.0: Describes the develo pment and conclusions of the CSM work, including the industrial block flow diagrams used to develop
the industrial CSM, the industrial CSM itself, and the rationale for selection of complete pathways;

4 Facilities that manufacture D 4 and/or D 5 on-site.

5 Facilities that mix or blend D 4 and/or D 5 to create products.

6 Facilities that react D 4 and/or D 5 to create other substances.FINAL

ERM 

### 2 January 2012  

### Section 4.0: Presents the mass balanc es calculated from the input and output data provided by the Member Companies. Input and output streams data provided by the SEHSC Member Companies are not included in this report to av oid Business Confidentiality and

Antitrust issues;

 

### Section 5.0: Discusses the POTW bl ock flow diagram and CSM; and

 

### Section 6.0: Summarizes the conclusions of the work.FINAL

ERM 

### 3 January 2012 

### 2.0 FATE AND TRANSPORT INFORMATION

Both D 4 

### and D 5 

### have been extensively evaluated for potential

environmental effects on both humans and ecological receptors. The physico-chemical and environmental fa te properties listed below indicate that both substances are sparingly soluble in water, adsorb strongly to solid particles in the presence of or ganic carbon, volatilize rapidly and hydrolyze slowly at neutral pH but mu ch faster at the lower and higher pH values more commonly found in the environment. Based on data contained in the GEMS/WATER data bank, most average annual pH values are between 6.5 and 8.3, with a global median pH of 7.7. 7

Substance Information D 4 Source D 5 Source Physico-Chemical Properties Solubility 0.056 mg/L at 23 °C 0.017 mg/L at 23-25°C Log Kow (n-octanol-water partition coefficient) 6.49 8.03

Vapor pressure 132 Pa at 25°C 33.2 Pa at 25°C Henry’s Law Constant (Pa m 3 / mol) 1,214,000 at 25°C UK D 4 Report 8

3,342,000 at 25°C UK D5 Report 9

Environmental Fate Properties (pH 4) 1.8 h at 25°C (pH 5) 96 h at 25°C (pH 7) 144 h at 25°C (pH 7) 1704 h at 25°C Hydrolysis half-lives

(pH 9) 1 h at 25°C UK D 4 Report (pH 9) 24 h at 25°C UK D 5 Report

Log Koc (organic carbonwater partition coefficient) 4.22 Miller &
Kozerski,

2007 10 5.17 Canada D5

Review 11 and

Durhan and
Kozerski, 2007 12 Log K OA (n-octanol-air partition coefficient) 4.34 SEHSC,

2008 13 5.06

__ 14

7 United Nations Environment Programme, Acid ification of Surface Waters, available at http://www.gemswater.org/atlas-gwq/acid-e.html.

8 Environment Agency (2009a). Environmental Risk Assessment Report: Octamethylcyclotetrasiloxane, Bristol, UK, April 2009.

9 Environment Agency (2009b). Environmental Risk Assessment Report: Decamethylcyclopentasiloxane, Bristol, UK, April 2009

10 Miller, J.A. and Kozerski, G.E. (2007). Soil-Wate r Distribution of Octamethylcyclotetrasiloxane (D 4 ) Using a Batch Equilibrium Method. Report to CES. Dow Corning Report No.: 2007-I0000-58266.

11 Siloxane D 5 Board of Review (2011). Report of the Board of Review for D 5 , Canada, October 20, 2011.

12 Durham, J., Kozerski, G.E., Miller, J.A., and Sush ynski, C.M. (2007). Soil-Water Distribution of Decamethylcyclopentasiloxane (D5) Using a Batch Equilibrium Method. Report to CES. Dow Corning Report No.: 2007-I0000-58258.

13 SEHSC (2008). Comments on Health and Environment Canada’s Draft Screening Assessments for Octamethylcyclotetrasiloxane (D 4 ; CAS No. 556-67-2), Canada Gazette, Part 1, Volume 1411, No. 20, May
17, 2008.

14 Xu, S. (2009). Temperature dependence of Air/Water, 1-Octanol/Air, 1-Octanol/Water partitioning coefficients of octamethylcyclotetrasiloxane (D 4 ), and decamethylcy clopentasiloxane (D 5 ). Centre Européen des Silicones (CES). CES Report. September 25, 2009.FINAL

ERM 

### 4 January 2012 

### The distributions of emissions shown below, which were developed for North American regional environments , indicate that most of the D 4 

### and

D 5 

### emitted to the environment partitio n preferentially to air for both compounds.

Distribution of Mass Remaining at Steady State (%):

Emitted to: Air Water Soil Sediment Source

D 4 Air (100%) 100.0 0.0 0.0 0.0 Water (100%) 8.66 45.8 0.0 45.6 Soil (100%) 88.5 0.0 11.5 0.0 Realistic emission (Air 85%, Water 1%, Soil 14%) 96.0 1.14 1.69 1.13 Kim, 2011a 15

D 5 Air (100%) 99.9 <0.1 <0.1 <0.1 Water (100%) 0.744 5.21 0 94.0 Soils (100%) 71.2 0 28.7 0 Realistic emission (Air 95%, Water 0.5%, Soil 4.5%) 73.5 1.32 1.29 23.9 Canada D 5 Review 16 and
Kim, 2011b 17



### Distribution of D 4 

### and D 5 

### in the global environment is lower than for the regional environment. The distributi on in surface media (water, soil and sediment) calculated by the regional model will be much higher since the air mass above a regional environment is limited to only a small part of the troposphere, which may not be the case for substances with atmospheric half-lives on the order of those associated with D 4 

### and D 5



### .

According to the sources referenced above, both D 4 

### and D 5 

### are rapidly degraded in air via photo-oxidation and removed from soil via volatilization and surface catalyzed hydrolysis, but degraded slowly in sediments. When discharged to water, a major fraction of D 4 

### and D 5 

### partitions to air and sediment due to the low water solubility, high Henry’s Law constant, and relatively high organic carbon-water partition

coefficient of the substances. An y amount remaining in water is hydrolyzed at a rate that depends on water pH and temperature and is transported to downstream water bodies where the same removal mechanisms take place, providing mo re opportunity for volatilization and deposition to sediment to remove D 4 

### and D 5 

### from the water.

Half-lives of D 4 

### and D 5 

### in the different environmental media are shown on the next page. Those half-lives were calculated based on a low OH

15 Kim, J. (2011a). Fate, Distribution and Transport of Octamethylcyclotetrasiloxane (CAS No. 556-67-2) as Predicted by Multimedia Fugacity Modelin g. Dow Corning Report No.: 2011-I0000-64103.

16 Siloxane D 5 Board of Review (2011). Op. cit.

17 Kim, J. (2011b). Fate, Distribution and Transport of Decamethylcyclopentasiloxane (CAS No. 541-02-6) in the Environment as Predicted by Multimedia Fu gacity Modeling. Dow Corning Report No.: 2011-I0000-

64103.FINAL

ERM 

### 5 January 2012 

### concentration (5×10 5 

### molecule/cm 3 

### ), instead of the global average OH

concentration of 7.5×10 5 

### molecule/cm 3 

### , which would result in shorter

half-lives. Half-lives for both D 4 

### and D 5 

### in air and soil are less than 14 days; in sediments, the half-lives of D 4 

### and D 5 

### are estimated at 1 year and 8.5 years, respectively. Deposition from air to ground level via rainfall, snow, and aerosols is not expected to be significant because of the low water solubility, high Henry’s Law co nstant, and relatively low n-octanolair partition coefficient of the substa nces. Room-temperature n-octanol-air partition coefficients less than 6.5 are considered to be too “volatile” to deposit through dry-deposition process, even under the cold Artic

climate. 18,19

Environmental Compartment Half-life (days)

D 4 Source D 5 Source

Air 14 (photo-oxidation) 10 (photo-oxidation)

Water 16.7 at pH 7 and 12°C (hydrolysis) 5.75 to 14.4 (volatilization) 315 at pH 7 and 12°C (hydrolysis) Water (sediment) 1 year (degradation) 8.5 years(degradation)

Soils 0.05 – 5.3 (degradation) UK D 4 Report 20

0.07 (degradation) Canada

D 5 Review 21



### Based on the properties presented in this section, ERM concluded that D 4 

### and D 5 

### behave similarly in the environm ent and that a single CSM could be used to represent both substances , provided the type of emissions from

the different facilities were similar.

18 Finizio, A., Mackay, D., Bidleman, T., Harner, T. (1997). Octanol-air Partition Coefficient as a Predictor of Partitioning of Semi-volatile Organic Chemicals to Aerosols

, Atmospheric Environment

, 31 (15, 2289-2296.

19 Wania, F. (2003). Assessing the Potential of Persistent Organi c Chemicals for Long-Range Transport and Accumulation in Polar Regions

, Environ. Sci. Technol.

, 37 (7), 1344-1351.

20 Environment Agency (2009a). Op. cit.

21 Siloxane D 5 Board of Review (2011). Op. cit.FINAL

ERM 

### 6 January 2012 

### 3.0 CONCEPTUAL SITE MODEL FOR D 4 

### AND D 5 

### INDUSTRIES

Based on the conclusion of the eval uation of the fate and transport

information obtained from scientific literature and studies (Section 2.0) and block flow diagrams provided by the Member Companies for D 4 

### and

D 5 

### (described in this section), ERM determined that a single, generic CSM could be used to represent human and ecological exposure to both substances for all facility types. A de scription and an evaluation of the block flow diagrams provided by the Member Companies (Figures 1 through 5) are presented in Section 3.1. Section 3.2 describes the resulting CSM diagram, which is shown in Figure 6.

3.1 GENERIC BLOCK FLOW DIAGRAM TEMPLATES

The SEHSC prepared a generic block diagram template for manufacturers and a separate template for formulators. Three templates were provided to the processors, with the only diffe rences being (1) the presence of an on-site wastewater treatment plant (WWTP), and (2) whether the discharge point is a POTW or surface water. All three options resulted in the eventual discharge of treated wastewater to surface water, and were considered to be sufficiently similar to represent the processors as a combined group. The templates are typical of the different facilities, but not all processing steps are present in all facilities.

3.1.1 Manufacturer Block Flow Diagram Description

The manufacturers block flow diagram shows precursor processes, reaction, separations, and storage ta nks, and loading operation as the processes that lead to the production of D 4 

### and D 5 

### (Figure 1). The input material is used in the precursor proc esses, which result in the production of dichlorodimethylsilane, the precursor of the PDMSs. Dichlorodimethylsilane is then hydrolyzed with aqueous hydrochloric acid in continuous, closed reactors to produce siloxanes, resulting in cyclic and linear oligomeric siloxanes th rough silanol-silanol, silanolchlorosilane polycondensation. Further processing is also performed to remove residual acid and chloride and recover hydrochloric acid for reuse in the precursor processes.

Linear siloxanes may then be converted into cyclic siloxanes to increase

the amount of D 4 

### and D 5 

### produced and to improve their purity. The reaction product is a mixture of PDMS s with different molecular weights.FINAL

ERM 

### 7 January 2012 

### Separation processes recover the differe nt chain-length distributions at different stages, and may include phase separation, flash distillation, or fractionation distillation. From there, the different products are stored separately until they are packaged for sale to off-site customers or for onsite processing.

Due to the highly reactive nature of the organochlorosilanes when in
contact with water or silanols, it can be assumed that they are completely consumed in the hydrolysis/polymer ization process, given that the conditions of the reaction will add enough water or other reagent to consume all the chlorine atoms. It is therefore not necessary to consider exposure of humans or the environm ent to organochlorosilanes during further downstream processing and use of PDMS polymers.

Volatile organosilanes and hydrochloric acid are emitted as gases to some extent during the reactions, separation s, storage, and loading operations. Those gases are collected by local exhaust ventilation systems and transported to abatement systems, including incineration and scrubbers, from which air emissions are vented to the atmosphere. Fugitive emissions may be produced throughout the facility, including in valves, pumps, drains, and the on-site WWTP, if present. The water produced in

the reaction vessels and in the scru bbers is typically discharged to a wastewater storage tank, from which it may go to either an on-site or an off-site POTW. In either case, the treated water is discharged to a surface water body.

The sludge produced in the on-site WWTP and solid waste produced during the reaction and separation steps are disposed of at on-site landfills or shipped to off-site management sy stems. Depending on the type of solid waste, these management syst ems may include incinerators, energy recovery systems or other beneficial use, or landfills. None of the biological sludge or other solid wastes is disposed of as fertilizer or via land application.

3.1.2 Formulator Block Flow Diagram Description

Figure 2 shows the block flow diagram for formulators. The D 4 

### /D 5 

### products are stored as raw materi als and mechanically pumped into mixing equipment, where they are mixed with other materials to form products used by industrial facilities or consumers. Formulation may occur continuously or in batch processe s, and typically in closed reactors. Product is fed into packaging systems for shipment to customers in bulk

or in small containers.FINAL

ERM 

### 8 January 2012 

### Both the mixing and packaging equipment typically have local exhaust ventilation systems that collect any gases produced during the formulation and transport them to pollution control equipment (scrubbers, condensers, energy recovery systems), with a minimal portion of the incoming gases being released to the air as point sources. Fugitive air emissions may be produced throug hout the facilities, in equipment such as storage tanks or containers, valves, and pumps. Wastewater is generally only produced during mixing, and is either treated at an on-site facility (at D 4 

### and/or D 5 

### manufacturing or processing wastewater treatment systems) or discharged via sewer to a POTW. Solid waste is produced in both the mixing and pack aging steps; this waste is sent off site for disposal, which may include thermal processes or landfilling.

3.1.3 Processor Block Flow Diagrams Description

There are a large number of polymers that can be prepared via polymerization of D 4 

### (99% pure or in combination with D 5 

### ), including high performance silicone oils and gums , silicone elastomer intermediates, and polymers used in the production of solvents, diluents, cosmetics, and perfumes. 22 

### Various end blockers (i.e., materials that stop the polymerization reaction) can produce a wide range of functionalized siloxanes containing functional groups such as phenyl, amino alkyl, or vinyl. Polymerization is catalyzed by a strong acid or a strong base. 23



### With reference to Figures 3 through 5, the D 4 

### /D 5 

### products are stored as raw materials and mechanically pumped into continuous or batch reaction vessels for further processing. All st eps in the process (storage, reaction, and purification) are generally carried out in closed systems with local exhaust ventilation that collects and transports gases produced during the different processing steps to a recove ry system to maximize the use of D 4 

### and D 5 

### raw materials. The waste gases produced in the recovery equipment are typically routed to abatement systems, including scrubbers, condensers, and energy re covery systems. Fugitive air emissions can be produced from equipment such as valves, pumps, drains, or the wastewater treatment system, if present on site.

All processing steps may also produce wastewater, which is typically routed to a storage area from where it is discharged into an on-site WWTP, an off-site POTW, or pretreat ed in an on-site WWTP and then

22 Bluestar Silicones (1997). Technical Data Sheet n° SIL 97 127 3, March 1997.

23 Colas, A. (2007). Introduction to Silicone Chemistry, chapter in Inorganic Polymers , Nova Science

Publishers.FINAL

ERM 

### 9 January 2012 

### discharged to an off-site POTW. Th e solid waste produced during the reaction, recovery, and air emission abatement systems is shipped to an off-site waste management facility.

3.1.4 Basis for a Single CSM for All Types of Facilities

The descriptions in Sections 3.1.1 through 3.1.3 indicate that the block diagram for each type of facility included emissions to air, water, and
land, as summarized below. Therefor e, ERM concluded that a single CSM was appropriate for all types of facilities.

Type of Emission Type of Facility To Air To Water To Land Air Emissions through Vents

and Abatement Systems (Point Source Emissions) On-site or Off-site WWTP

Effluent Manufacturers

Fugitive Air Emissions Storm Water Discharge to

Surface Waters Solid Waste to Fuel Recovery

Air Emissions from Pollution

Control Equipment (Point Source Emissions) Waste from Operations

Formulators

Fugitive Air Emissions Wastewater to POTW or for Offsite Treatment Activated Carbon Waste for Fuel Recovery

Point Source Air Emissions Industrial Waste Water Discharge to POTW Processors

with no Onsite WWTP Fugitive Air Emissions Storm Water Discharge to

Surface Waters Solid Waste Disposal to

Off-site Waste Management

Point Source Air Emissions Treated Industrial Waste Water Discharge to Surface Waters Processors

with On-site

WWTP Fugitive Air Emissions Storm Water Discharge to

Surface Waters Solid Waste Disposal to

Off-site Waste Management

Point Source Air Emissions Treated Industrial Waste Water Discharge to Off-site POTW Processors

with On- and

Off-site

WWTP Fugitive Air Emissions Storm Water Discharge to

Surface Waters Solid Waste Disposal to

Off-site Waste Management



### 3.2 GENERIC D 4 

### AND D 5 

### INDUSTRIAL CSM FOR HUMAN AND

ECOLOGICAL RECEPTORS

3.2.1 Procedures

Consistent with generally accepted practice, 24,25,26 

### ERM prepared a generic CSM diagram (Figure 6) summarizing the following:

 

### Multimedia release pathways into the environment (such as potential release from storage tanks, wastewater treatment, and stacks);

24 USEPA (2001). Op. cit.

25 USEPA (1996). Op. cit.

26 USEPA (1988). Op. cit.FINAL

ERM 

### 10 January 2012  

### Primary, secondary, and tertiary so urces and release mechanisms for each of these pathways;

 

### Potential exposure routes specific to each medium (air, soil, surface water, sediment, and groundwater); and

 

### Environmental receptors specific to each medium, including both human and ecological receptors where relevant.

Worker exposure pathways resulting from industrial operations are not considered given that in the U.S. thes e exposures are subject to regulation by the Occupational Safety and Health Administration (OSHA). As previously indicated, information ab out emissions from off-site facilities where the SEHSC Member Companies send some of their waste is not

included in the mass balances discusse d in Section 4.0. Furthermore, not all of the pathways identified in the diagram are likely to occur at each of the SEHSC Member Company facilities; the application of this diagram to any specific facility is subject to verification.

Based on the fate and transport properties of D 4 

### and D 5 

### , discussed in Section 2.0, ERM identified pathways that are complete, i.e., those pathways that lead to a reasonable expectation of potential exposure to humans or ecological receptors. The identification of complete pathways

for D 4 

### and D 5 

### was based on available literature, known properties of the chemicals, and the information pr ovided to ERM by the Member Companies via SEHSC.

Figure 6 presents the industrial CSM. Potentially complete and incomplete pathways are marked in the figure as solid and dotted lines, respectively. The evaluation of whether each of the pathways is potentially complete or not is described below.

3.2.2 Air Pathways

With reference to Figure 6, air emissions of D 4 

### and D 5 

### may result from air treatment equipment and fugitive emission sources such as valves, pumps, wastewater treatment plants, beneficial sludge reuse, landfills,
surface water, and surface soil. Thes e air emissions are airborne vapors that are dispersed in the atmosphe re and transported by the wind. During that transport, rainfall will not result in deposition of D 4 

### and D 5 

### because of the low water solubility, high air/water partition coefficient (thus no wet deposition), and relatively low n-octanol-air partitionFINAL

ERM 

### 11 January 2012 

### coefficient (thus insignificant dry deposition) 27 

### of the substances. Therefore, the deposition pathway to plants, surface soil, and surface water is an incomplete pathway.

Once emitted to air or volatilized from other media, D 4 

### and D 5 

### remain in the air until they are photo-oxidized . They may be inhaled by human receptors either at the point of volat ilization or downwind of the emission source. This is considered a complete pathway.

3.2.3 Surface Soil

During biosolids land application on surface soils, runoff may potentially transport D 4 

### and D 5 

### to surface water, but this pathway is also considered incomplete because of the low solub ility and high organic carbon-water partition coefficient of the subs tances. From surface soils, D 4 

### and D 5 

### are unlikely to infiltrate into the ground water, but may be eroded by wind or volatilized and transported to air. Infiltration and migration into ground water and from ground water to surface water are minimized by the high adsorption to organic carbon and lo w solubility of the substances, which would limit their migration from soil to ground water. As a result, the pathways related to ground water are considered incomplete.

The exposure of human receptors to ai r as a result of volatilization from surface soil is considered complete, given the elevated Henry’s Law

Constants for D 4 

### and D 5 

### . Pathways via direct exposure to surface soil via ingestion, uptake, or direct contact are considered to be incomplete, because of the rapid degradation of D 4 

### and D 5 

### in soil under dry conditions and rapid volatilization un der wet conditions.

3.2.4 Surface Water

Sources of emissions to surface wa ter are wastewater treatment plants, beneficial sludge reuse, and process equipment. Because of the low water solubility of the substances and rapid volatilization and adsorption to sediments (note that sediment pathways are retained), ingestion of, uptake from, or direct contact with surface water are considered incomplete pathways. Volatilizatio n to air from surface water and subsequent exposure of human receptors is considered a complete pathway.

27 Xu, S. (2010). Modeling Assessment of the Contribution from Surface/Air Exchange to the Deposition Potential for cVMS. Dow Corning Technical Report 2010-I0000-62571.FINAL

ERM 

### 12 January 2012 

### 3.2.5 Sediments

Exposure of benthic plants, invertebrat es, as well as amphibians and fish to sediments via uptake, direct cont act, and ingestion of benthic food, respectively are also considered complete pathways, because D 4 

### and D 5 

### are relatively persistent in sediments. Exposure of human receptors to D 4 

### and D 5 

### in sediments via the food chain (i.e., by ingesting amphibians and fish) is considered an incomplete pathway because of the lack of biomagnification of D 4 

### and D 5 

### through the food chain.

3.2.6 Landfills to Air and Ground Water

Solid wastes generated from operations , activated carbon sent to off-site waste management facilities, and sludge treatment may be disposed in
landfills, where D 4 

### and D 5 

### may volatilize into the air. This is a complete pathway. As previously indicated, in filtration of the substances into the ground water is unlikely because of the high soil-water partition coefficient and low solubility of the substances, and is considered to be an incomplete pathway.

3.2.7 Summary

The pathways retained for further consideration in fate and transport models and risk assessments include the following:

 

### Inhalation exposure resulting from dispersion in air (this pathway applies only to human receptors, because ecological receptors are not typically evaluated for inhalation exposure risk).

 

### Exposures via sediment, includin g direct exposure for bottomdwelling biota and indirect exposure via the food chain to ecological

receptors.

In summary, the generic industrial CSM summarizes a wide range of potential pathways for D 4 

### and D 5 

### , but only air for human receptors and sediment for ecological receptors are considered to be complete pathways.FINAL

ERM 

### 13 January 2012 

### 4.0 MASS BALANCE DATA AGGREGATION

4.1 PROCEDURES

ERM reviewed data for 13 SEHSC Member Company sites, including two manufacturers, nine processors, and seven formulators. A total of six companies provided worksheets with in put and output streams (Table 1).

The emission streams are listed in Section 3.1.4. Because the Member Companies have no information about emissions at off-site facilities, those

emissions are not included in the mass balances.

Data aggregation decisions were dr iven by the need to protect
Confidential Business Information, i.e ., data were aggregated only if three or more Member Companies reported data for the particular stream
evaluated. Thus, manufacturers’ data are not presented because there are only two manufacturers to provide info rmation. In addition, all reporting processors were aggregated into a si ngle group because there were only two processors in one of the catego ries and fewer than three reporting Member Companies for some of the st reams in the other two categories. The differentiation between the presen ce or absence of an on-site WWTP at processing facilities was deemed unnecessary for the mass balance and the fate and transport evaluations.

Arithmetic averages and standard de viations were calculated for each stream. However, because the produc tion rate range encompasses two orders of magnitude for the processors and four orders of magnitude for the formulators, the SEHSC and ERM ag reed that the data would be best represented by weighted averages calculated based on the input amount

of D 4 

### or D 5 

### to the formulator or processor fa cilities. Weighted averages for

each stream were calculated as the sum of the data for the stream for each facility multiplied by the ratio of the input amount D 4 

### or D 5 

### for that facility to the sum of the input amount D 4 

### or D 5 

### for all facilities. The equation is as follows:

.,3,2,1 54 54

etc n n AStream 

### Facilities AllfororDDInputTotal nFacilityforDorDInput AStream Avg Weighted

 

#         

 



### Where Stream A

n 

### is each specific stream for which data were provided by more than three Member Companies.FINAL

ERM 

### 14 January 2012 

### The facilities didn’t report data for so me of the streams because: (1) no

information was available to calculate the emission rate, or (2) the stream

was combined with the waste from othe r on-site activities (manufacturing, formulation). These facilities were excluded from the weighted average, i.e., the “Total Input D 4 

### or D 5 

### for All Facilities” in the equation above did not include the input for the facility no t reporting data. If the facility did not produce the specific stream or believed the stream contained no D 4 

### or
D 5 

### , the stream was included in the mass balance as a zero value. Facilities that reported data for the same streams did so based on a mass balance or on existing permits. This method avoided artificially inflating the value for any particular stream by disregarding zero values.

4.2 MASS BALANCE DATA AGGREGATION RESULTS

4.2.1 Manufacturers Data Observations

As previously indicated, no aggregation of the manufacturer’s data was possible because only two Member Companies reported data as

manufacturers of D 4 

### and D 5 

### . However, it is noteworthy that both

manufacturers indicated that there wa s no contact of storm water with D 4 

### or D 5 

### at their facilities.

4.2.2 Formulators Data Aggregation Observations

No aggregation was possible for formulators of D 4 

### because fewer than three Member Companies formulate with D 4 

### . Table 2 summarizes the arithmetic weighted averages for the output streams in terms of input D 5 

### and the number of Member Companies th at reported data for each stream. Observations on the information presented in Table 2 include:

 

### The sum of the emission rates of D 5 

### with respect to the input D 5 

### was greater than 1. This inconsistency is explained by the way the calculations were performed, based on independent records of input and outputs. The excess amount wa s allocated among all six output streams based on their proportion to the sum of the output streams.

 

### Mass-balanced emissions range from approximately 10 -5 

### to 10 -3 

### lb

D 5 

### /lb D 5 

### to storage area. The mass balance did not alter the order of magnitude of the emissions appreciably, because the allocated difference was only -1.6% of the in put stream (see Tables 2 and 3).

 

### Stream 2 - Waste from Operations has the greatest emissions. However, this stream generally receives further treatment via incineration, fuel blending, or other thermal treatment process thatFINAL

ERM 

### 15 January 2012 

### will result in significant reduction or elimination of D 4 

### or D 5 

### before discharge to the environment.

 

### Operations time ranges between 480 and 7,008 hr/yr, with a weighted average of 5,700 hr/yr.

The mass balance calculations for the average formulating facility for D 5 

### are presented in Table 3. To close the mass balance, the difference between input and output streams was allocated to each of the output streams based on their proportion of th e total of all four output streams. The Member Companies agreed that this allocation appeared reasonable.

Figure 7 presents the mass balance in the block diagram for formulators. As shown in the figure, the arithmetic weighted average for D 5 

### in the product is 99.87%, with approximately one-half of the remaining 0.13% (0.059%) emitted as Stream 2 – Waste from Operations, which may be further treated prior to discharge.

4.2.3 Processors Data Aggregation Observations

Table 4 presents the arithmetic weighted averages for the output streams in terms of input D 4 

### or D 5 

### and the number of Member Companies that reported data for each stream. Obse rvations on the information presented

in Table 4 include:

 

### The range of emission rates for proc essors is similar to those for the

formulators.

 

### The emissions of both D 4 

### and D 5 

### to air are greater than those to water.

 

### Stream 7 – Solid Waste Disposal to Off-site Waste Management is greater than the emissions to either air or water or their sum. Like

Stream 2 for the formulators of D 5 

### , this stream undergoes further thermal treatment that is expected to reduce the amount of D 4 

### and D 5 

### released to the environment significantly.

 

### The range of operation time is 304 to 8,760 hr/year, with an arithmetic weighted average of 8,400 hr/yr.

Table 5 shows the mass balance calcul ations for the output streams in terms of input D 4 

### or D 5 

### for the average processing facility that uses D 4 

### or
D 5 

### . The mass balance for D 4 

### was closed by allocating any difference between the input and the total of th e output Streams 3 through 7 to a “D 4 

### Raw Material Reacted or Remaining in the Polymer” stream, to resolve

differences in the calculation methods fo r the reported data. An allocation

of D 5 

### streams was completed in the same manner as for the Formulators ofFINAL

ERM 

### 16 January 2012 

### D 5 

### , because the sum of the outputs was gr eater than the sum of the input.
In this case, the “D 5 

### Raw Material Reacted or Remaining in the Polymer” was equal to the value for Stream 2 – Final Polymer Produced. The Member Companies agreed that this allocation procedure appeared

reasonable.

Figures 8 and 9 present the mass balances in the block diagrams for processors of D 4 

### and D 5 

### , respectively. Typically, D 4 

### and/or D 5 

### are utilized as monomers and processed into various types of polysiloxane polymers. As shown in Figure 8, the arithmetic weighted average for D 4 

### reacted or remaining in the product is 99.66%, with approximately two-thirds of the remaining 0.34% (0.20%) emitted as Stre am 7 – Solid Waste Disposal to Off-site Waste Management and almost all of the rest of the input D 4 

### emitted to air (0.14%).

The mass balance for D 5 

### in Figure 9 shows that the arithmetic weighted average for the amount of D 5 

### reacted or remaining in the product is 99.29%. More than three-quarters of the remaining 0.71% (0.58%) is

emitted as Stream 7 – Solid Was te Disposal to Off-site Waste Management. The next higher emission is to air (0.13%), including both point source and fugitive emissions, with only 0.0087% emitted to water.

The storm water emissions are minima l for both substances (0.00038% for

D 4 

### and 0.000011% for D 5 

### ).FINAL

ERM 

### 17 January 2012 

### 5.0 GENERIC POTW CSM

5.1 GENERAL TREATMENT REQUIREMENTS

The Clean Water Act establishes that POTWs must treat wastewater to meet secondary treatment requirements , which are specified in Part 133 of Title 40 of the Code of Federal Regulations (40 CFR 133). Secondary

treatment consists of removal of organic compounds via biological treatment, defined in terms of (1) bo th a minimum removal efficiency and final effluent levels of biochemical oxygen demand (BOD, a measure of the organic content of wastewater) an d total suspended solids; and (2) a range of pH levels in the final effluent.

Preliminary and primary treatment to remove solids is generally used to prevent interference with the aeration system in the biological treatment system. Advanced wastewater treatment may also be used at some POTWs to remove suspended solids, nutrients (i.e., nitrogen and phosphorus), toxic organics, or toxic metals. The need for advanced wastewater treatment at a specific POTW depends on the efficiency of its biological treatment system, the local effluent discharge requirements, type of industrial wastes it receives, and any reuse/recycling requirements for the treated effluent or the sludge produced. The sludge produced is usually dewatered and/or treated to reduce its disposal cost and to meet the requirements of cert ain disposal methods (such as those defined in 40 CFR 503 for beneficial use as a fertilizer).

5.2 POTW POTENTIAL TREATMENT TECHNOLOGIES

There are many technologies that can be used for wastewater treatment in POTWs and new technologies or improv ements to existing technologies are continuously developed. Similarly, there are several liquid effluentand sludge disposal options. Table 6 presents a list that is not allinclusive. The most common treatment processes at POTWs include: 28

 

### Primary Treatment. Grit chambers to remove dense inert particles, screens to remove rags and other large debris, and gravity settling

28 USEPA (2009). Nutrient Control Design Manual, State of Technology Review Report , EPA/600/R-09/012.FINAL

ERM 

### 18 January 2012 

### tanks (primary clarifiers) to remove settleable inorganic and organic

solids.

 

### Secondary Treatment. Includes biological processes to remove colloidal and soluble organic matter, followed by liquid effluent disinfection.

 

### Advanced Treatment. Liquid effluent filtration and nutrient removal.

Activated sludge was the secondary treatment system most commonly installed in the 1970s and 1980s (in response to the 1972 Clean Water Act), because of their demonstrated perfor mance and relative ease of control compared to other systems available at that time. In fact, the USEPA developed air emission factors for POTWs using an activated sludge system as part of the typical POTW. 29 

### An activated sludge system includes an aerated, completely-mixed basin and a clarifier. A portion of the sludge removed in the clarifier by settlement is returned to the aerated basin to improve organics removal by using already acclimated microorganisms.

The most common disposal methods for the liquid effluent and sludge are discharge to surface water bodies (rivers, lakes, oceans) and land application, respectively. 30,31



### 5.3 POTENTIAL EFFECTS OF POTW TREATMENT TECHNOLOGIES ON

THE FATE AND TRANSPORT OF D 4 

### OR D 5



### With a few exemptions, a common elem ent in the treatment technologies presented in Section 5.2 is that they allow volatilization of compounds and produce two streams: a liquid and a so lid stream. In fact, the traditional wastewater treatment technologies (screens, primary clarifier, activated sludge system, and chlorination) are usually open to the atmosphere and can have a very large surface area that promotes volatilization of compounds. Volatilized compounds are sometimes collected and treated, but this is done only if required by the local authority (e.g., because of odors), if the POTW receives hazardous air pollutants (HAPs) above
certain levels, or if the POTW treats the HAPs in wastewater from an industrial facility subject to the NESHAP regulations. 32 

### Most of the

29 USEPA (1991). AP-42 Emission Factors for POTWs, Section 4.3.

30 USEPA (2009). Op. cit.

31 USEPA (2006). Emerging Technologies for Biosolids Management , EPA 832-R-06-005.

32 National Emission Standards for Hazardous Air Pollutants: Publicly Owned Treatment Works, Federal Register, Vol. 64, No. 206, 57572-57585, October 26, 1999.FINAL

ERM 

### 19 January 2012 

### volatilized compounds can, therefore, be considered to be fugitive

emissions.

The variety of technologies used in POTWs makes it difficult to predict

the fate of D 4 

### and D 5 

### in POTWs, although POTW monitoring in Canada

demonstrated D 4 

### and D 5 

### removal efficiencies of >97% regardless of the secondary or tertiary treatment technologies used. Transfer and storage between processes and some of the processes used in a POTW may result

in air emissions of D 4 

### or D 5 

### , which may or may not be captured and controlled (as indicated above). Biol ogical treatment systems, used to meet the secondary treatment requirements, are typically operated at a neutral pH, which results in a slower hydrolysis rate of D 4 

### or D 5



### . Advanced wastewater treatment may result in complete removal of D 4 

### or
D 5 

### from effluent wastewater (such as air stripping), but not all POTWs have a treatment system that accomp lishes this purpose. Some of the sludge processes may also remove D 4 

### or D 5 

### . For example, thermal

reduction would result in transformation of D 4 

### or D 5 

### into CO 2 

### , water, and silicon and lime stabilization, perfor med at pH values greater than 12, would result in faster hydrolysis. 33



### 5.4 DESCRIPTION OF THE “TYPICAL” POTW

As a result of the variety of technologies available for POTWs and the potential effects identified in Section 5.3, ERM designed a “typical” POTW for use in developing the CSM. Th e typical POTW, as designed, employs widely used technologies that are not expected to remove D 4 

### or D 5 

### completely, although they may do so. This type of POTW would be present in mid-size and small-size towns, which generally do not have regulatory requirements as stringent as those in the large POTWs found in densely populated areas. The assume d typical POTW uses primary and secondary wastewater treatment and land application for sludge disposal.

This selection is reasonable be cause (1) according to USEPA, approximately 50% of the POTWs had only secondary treatment technologies and served 41% of the population in the U.S.; 34 

### (2) land application is the POTW sludge disposal method that could result in the most exposure to the environment; and (3) the absence of advanced treatment makes it more likely that there would be some remaining D 4 

### and D 5 

### in the effluent and/or the sludge.

33 Water Environment Federation (WEF) and American Society of Civil Engineers (ASCE) (2010). Design of Municipal Wastewater Treatment Plants , WEF Manual of Practice No. 8, ASCE Manuals and Reports on Engineering Practice No. 76, 5th Editio n, McGraw Hill, New York, New York.

34 USEPA (2008). Clean Watershed Needs Survey 2008 , Report to Congress, EPA 832-R-10-002.FINAL

ERM 

### 20 January 2012 

### A block diagram of the typical POTW is presented in Figure 10. It includes a pump station; primary treatment with coarse screening and primary sedimentation; secondary tr eatment via an activated sludge system (aeration basin, secondary clarification, and pumps to return sludge from the clarifier); and chlorination for disinfection. The liquid effluent is discharged to a surface water body.

In the typical POTW, sludge is collected, stored, blended (primary sludge with secondary sludge), anaerobically digested (to minimize odor generation, destroy pathogens, and redu ce the potential to attract vectors, in accordance with 40 CFR 503), d ewatered with filter presses, and disposed of via land application as a fertilizer. Sludge storage is required during parts of the year when land app lication is not feasible (i.e., because of limitations from cold weather, some crops growing seasons, or spring rains).

As indicated in Section 5.3, each of the equipment units used for treatment of the wastewater “mostly liquid” stream shown in Figure 10 have emissions to air, named “fugitive ai r emissions” because the typical POTW does not collect and treat emissions to air. Sludge is produced in the coarse screening, primary clarifie r, and secondary clarifier along the “mostly liquid” stream path. That slud ge is collected and stored to blend the primary and secondary clarifier sludges and improve the efficiency of the digestion system and to equalize th e load entering the digester. The blended sludge is then pumped to an anaerobic digester operating within the mesophilic temperature range (32 to 38 C), pH range of 6 to 8, and under anaerobic conditions over a detention time period of 15 to 20 days. 35



### From the anaerobic digestion tank, a “mostly-liquid” stream (“supernatant”), a stabilized sludge (“biosolids”), and a gaseous stream containing all gases produced during the digestion are generated. The gaseous stream goes to a waste gas burner where air is introduced to ensure complete combustion of the organic gases generated during the digestion process, thus removing any D 4 

### and D 5 

### in that stream. The filter presses, which are used for dewatering the sludge to reduce its volume, produce liquid and solid streams. All liquid streams produced during sludge treatment have relatively high organic carbon content, and are returned to the POTW pump station, to avoid the disruption of the biological processes that result from organic load variations. Equipment used during the transfer and processing of sludge, including pump

35 WEF (1996). Operation of Wastewater Treatment Plants , Manual of Practice 11, 5th Edition, Alexandria, Virginia.FINAL

ERM 

### 21 January 2012 

### stations, blending and storage tanks, filter presses, and storage and transfer units, also prod uce fugitive air emissions.

5.5 GENERIC CSM FOR HUMAN AND ECOLOGICAL RECEPTORS FOR

POTWS RECEIVING WASTEWATER CONTAINING D 4 

### OR D 5



### The generic POTW CSM diagram is shown in Figure 11. Like the industrial CSM, exposure pathways for POTW workers were not included. Furthermore, the processes and resulting pathways identified in the diagram may not occur at each of the POTWs that receive wastewater containing D 4 

### and/or D 5 

### ; the application of this diagram to any specific POTW is subject to verifi cation as to the processes used.

Based on the fate and transport properties of D 4 

### and D 5 

### , discussed in Section 2.0, ERM identified pathways that are complete, i.e., those pathways that lead to a reasonable expectation of potential exposure to

humans or the environment. The iden tification of complete pathways for

D 4 

### and D 5 

### was based on available literat ure, known properties of the chemicals, and the information pr ovided to ERM by the Member Companies via SEHSC. The POTW CSM diagram is similar to that of industrial facilities producing or handling D 4 

### or D 5 

### , with the exception that the primary sources are different and landfill disposal is not considered for the typical POTW. As a result, the pathways considered to be complete are the same:

 

### Inhalation exposure resulting from dispersion in air (this pathway applies only to human receptors, because ecological receptors are not typically evaluated for inhalation exposure risk); and

 

### Exposures via sediment, includin g direct exposure for bottomdwelling biota and indirect exposure via the food chain to ecological

receptors.FINAL

ERM 

### 22 January 2012 

### 6.0 CONCLUSIONS

On behalf of the SEHSC, ERM evaluated the data provided by six Member Companies to develop (1) a generic CSM for manufacturers, formulators, and processors of D 4 

### and D 5 

### ; (2) mass balances for formulators of D 5 

### and for processors of D 4 

### and D 5 

### ; and (3) a typical POTW block flow diagram and a generic CSM for POTWs. Manufacturers’ and D 4 

### formulators’ mass balances could not be calculated without violating business confidentiality, because fewer than three Member Companies provided

data.

Based on the evaluation presented in this report, ERM concluded the following for the industrial facilities:

 

### Aggregation of all facilities for the generic conceptual site model with arithmetic weighted averages of the emissions for the different types of facilities provide a useful summary of the potential fate, transport, and exposure pathways for these substances in the environment.

 

### The greatest emissions of D 4 

### and D 5 

### are those to air (at the same time, very small emission to water), given that the solid waste or waste from operation streams sent off-site for disposal are thermally treated before being released to the environment (assuming any D 4 

### or D 5 

### remained after treatment).

The typical POTW was considered to include primary treatment, activated sludge, chlorination, anaerobic digestio n of the sludge, sludge dewatering via filter presses, and sludge storage and transfer. End disposal included discharge to surface water for the liqui d stream and land application for the solid stream. This typical POTW was used to prepare a generic CSM for human and ecological receptors for POTWs that receive wastewater containing D 4 

### or D 5



### .

After assessing the chemical an d physical properties of D 4 

### and D 5 

### and the potential sources and pathways of exposure to human and ecological receptors, ERM concluded that the following two pathways were potentially complete for both the gene ric industrial facility and the generic

POTW:

 

### Inhalation exposure resulting from dispersion in air (this pathway applies only to human receptors, because ecological receptors are not typically evaluated for inhalation exposure risk).FINAL

ERM 

### 23 January 2012  

### Exposures via sediment, includin g direct exposure for bottomdwelling biota and indirect exposure via the food chain to ecological

receptors.

# TABLESTABLE 1MEMBER COMPANY FACILITIES THAT REPORTED DATASilicones Environmental, Health and Safety CouncilFINALFacility Type Company Name Location/Name ProvidedDow Corning Carrolltown, KYMomentive Performance Materials Waterford, NYBluestar Silicones USA Corp. Ventura, CADow Corning HIMs, Hemlock, MIDow Corning Auburn, MIDow Corning Greensboro, NCDow Corning Carrolltown, KYMomentive Performance Materials Waterford, NYShin-Etsu - Facility 1 Akron, OHBluestar Silicones USA Corp. Ventura, CADow Corning Greensboro, NCEvonik Goldschmidt Corporation Hopewell, VAShin-Etsu - Facility 2 Akron, OHWacker Chemical Corporation Adrian, MIMomentive Performance Materials Sistersville, W. Va.Momentive Performance Materials Waterford, NYDow CorningMidland, MIDow Corning Elizabethtown, KYProcessor, On- to Off-Site WWTPManufacturerFormulatorProcessor, No On-Site WWTPProcessor, On-Site WWTPERM31 January 2012TABLE 2SUMMARY OF DATA AGGREGATION BEFORE MASS BALANCE FOR FORMULATORSSilicones Environmental, Health and Safety CouncilFINALStreamNo. ItemLbs D4 / Lbs D4 toStorage AreaLbs D5 / Lbs D5 toStorage AreaNo. of Companies2 4Arithmetic AverageNA 1.40E-03Standard DeviationNA 3.42E-03Weighted Average NA 3.33E-05No. of Companies 2 4Arithmetic Average NA 5.19E-05Standard Deviation NA 1.36E-04Weighted Average NA 8.69E-06No. of Companies 2 4Arithmetic Average NA 1.00E+00Standard Deviation NA 1.00E+00Weighted Average NA 1.00E+00No. of Companies 1 3Arithmetic Average NA 4.80E-02Standard Deviation NA 1.13E-01Weighted Average NA 6.03E-04No. of Companies2 4Arithmetic AverageNA 9.49E-01Standard DeviationNA 1.07E-01Weighted Average NA 1.01E+00No. of Companies2 4Arithmetic AverageNA 3.20E-04Standard DeviationNA 7.58E-04Weighted Average NA 1.87E-04No. of Companies2 4Arithmetic AverageNA 1.12E-03Standard DeviationNA 2.86E-03Weighted Average NA 5.11E-04Key:NA = Calculation not performed to protect Business Confidentiality, as fewer than three companies reported dataWeighted Average =Stream DescriptionCalculated as the sum of: the result of multiplying each stream by the corresponding Stream 1 for each facility and dividingby the sum of the Stream 1 values for the facilities that reported values for the stream for which the weighted average wasbeing calculatedWaste Water Treatment / Storage AreaActivated Carbon Waste to Fuel RecoveryProduct Mixed with D4or D5for CustomersWaste from Operations1A1A2D4or D5to Storage AreaFugitive Air Emissions from SiteAir Emissions from Pollution Control Emissions5234ERM31 January 2012TABLE 3MASS BALANCE CALCULATIONS FOR FORMULATORS OF D5Silicones Environmental, Health and Safety CouncilFINAL12345678910111213141516171819202122A B C D E F GHStreamNo. Stream Description ItemLbs D5/ Lbs D5to Storage AreaApportionedLbs D5/ Lbs D5to Storage AreaMass-BalancedLbs D5/ Lbs D5toStorage AreaLbs D5/yr% ofStream 11D5to Storage AreaWeighted Average 1.00E+00 7,507,346A1 Point Source Air Emissions Weighted Average 3.33E-05 -5.34E-07 3.27E-05 246 0.0033%A2 Fugitive Air Emissions Weighted Average 8.69E-06 -1.40E-07 8.55E-06 64.2 0.00086%2 Waste from Operations Weighted Average 6.03E-04 -9.67E-06 5.93E-04 4,451 0.059%3Product Mixed with D5forCustomersWeighted Average 1.01E+00 -1.63E-02 9.99E-01 7,497,429 99.87%4Activated Carbon Waste to FuelRecoveryWeighted Average 1.87E-04 -3.00E-06 1.84E-04 1,380 0.018%5Waste Water Treatment / StorageAreaWeighted Average 5.11E-04 -8.20E-06 5.03E-04 3,776 0.050%--Total Streams A1, A2, and 2through 5Weighted Average 1.02E+00 -1.63E-02 1.00E+00 7,507,346 100.00%--Extra Lbs D5/ Lbs Raw MaterialConsumedWeighted Average -1.63E-02Data or Calculations:Columns A through D from Table 2.Column E is equal to Column D times Cell D10 divided by Cell D9 for Streams A1, A2, and 2 through 5.Column F is equal to Column D plus Column E for Streams A1, A2, and 2 through 5.Column G is equal to Column F times Cell G2 for Streams A1, A2, and 2 through 5. Cell G1 is the weighted averagefor Stream 1 and Cell G9 has the sum of the other six streams.Column H is equal to Column F, expressed as a percentage.Key:=Not applicable for Rows 2 and 10WeightedAverage =Calculated as the sum of: the result of multiplying each stream by the corresponding Stream 1 for each facility and dividing by the sum of theStream 1 values for the facilities that reported values for the stream for which the weighted average was being calculatedERM31 January 2012TABLE 4SUMMARY OF DATA AGGREGATION BEFORE MASS BALANCE FOR PROCESSORSSilicones Environmental, Health and Safety CouncilFINALStreamNo.ItemLbs D4/ Lbs D4Raw MaterialConsumedLbs D5/ Lbs D5Raw MaterialConsumedNo. of Companies6 5Arithmetic Average1.00E+00 1.00E+00Standard Deviation1.00E+00 1.00E+00Weighted Average 1.000E+00 1.000E+00No. of Companies 6 5Arithmetic Average 4.83E-01 6.78E-01Standard Deviation 5.32E-01 4.99E-01Weighted Average 7.95E-01 1.0037E+00No. of Companies 6 5Arithmetic Average 3.13E-03 1.68E-03Standard Deviation 5.92E-03 2.34E-03Weighted Average 1.36E-03 1.27E-03No. of Companies 6 5Arithmetic Average 6.67E-01 7.14E-01Standard Deviation 6.39E-05 3.94E-04Weighted Average 4.54E-05 1.50E-05No. of Companies6 5Arithmetic Average4.55E-05 4.47E-04Standard Deviation7.21E-05 1.08E-03Weighted Average 3.11E-05 8.81E-05No. of Companies6 5Arithmetic Average9.78E-06 4.69E-06Standard Deviation2.02E-05 1.24E-05Weighted Average 3.75E-06 1.16E-07No. of Companies6 5Arithmetic Average7.89E-03 7.03E-03Standard Deviation1.16E-02 9.89E-03Weighted Average 1.96E-03 5.83E-03Key:Weighted Average =Stream DescriptionCalculated as the sum of: the result of multiplying each stream by the corresponding Stream 1 for each facilityand dividing by the sum of the Stream 1 values for the facilities that reported values for the stream for whichthe weighted average was being calculatedSolid Waste Disposal to Off-site WasteManagementStorm Water Discharge to Surface WatersIndustrial Waste Water Discharge to POTWFugitive Air EmissionsPoint Source Air Emissions7456312 Final Polymer ProducedD4/D5Raw Material ConsumedERM29 January 2012TABLE 5MASS BALANCE CALCULATIONS FOR PROCESSORS OF D4AND/OR D5Silicones Environmental, Health and Safety CouncilFINAL123456789101112131415161718192021222324252627A B C D E F G H IJKStreamNo. Stream DescriptionItemReported LbsD4/ Lbs D4RawMaterialConsumedReported LbsD5/ Lbs D5RawMaterialConsumedApportionedLbs D5/ LbsD5RawMaterialConsumedMassBalanced LbsD5/ Lbs D5Raw MaterialConsumedLbs D4/ yr Lbs D5/ yrD4- % ofStream 1D5- % ofStream 11D4/D5Raw Material ConsumedWeighted Average 1.00E+00 1.00E+00 67,268,603 4,354,908--D4/D5Raw Material Reacted or Remainingin the Polymer9.97E-01 9.93E-019.93E-01 67,039,994 4,323,882 99.66% 99.29%2Final Polymer ProducedWeighted Average 7.95E-01 1.0037E+00 -1.08E-02 9.93E-01 53,467,165 4,323,882 79.48% 99.29%3Point Source Air Emissions Weighted Average 1.36E-03 1.27E-03 -1.37E-05 1.26E-03 91,626 5,477 0.14% 0.13%4Fugitive Air EmissionsWeighted Average 4.54E-05 1.50E-05 -1.61E-07 1.48E-05 3,051 65 0.0045% 0.0015%5Industrial Waste Water Discharge to POTWor Surface WaterWeighted Average 3.11E-05 8.81E-05 -9.46E-07 8.71E-05 2,094 379 0.0031% 0.0087%6 Storm Water Discharge to Surface Waters Weighted Average 3.75E-06 1.16E-07 -1.25E-09 1.15E-07 253 0.50 0.00038% 0.000011%7Solid Waste Disposal to Off-site WasteManagementWeighted Average 1.96E-03 5.83E-03 -6.26E-05 5.76E-03 131,585 25,104 0.20% 0.58%-- Total Streams 3 through 7 3.40E-03 7.20E-03 -7.74E-05 7.12E-03-- Total (Reacted plus Streams 2 through 7)67,268,350 4,354,908 100.00% 100.00%-- Total Streams 2 through 7 1.011E+00 -1.09E-02 1.00E+00--Extra Lbs D5/ Lbs Raw Material Consumed-1.09E-02Data and Calculations:1. Columns A through E from Table 4. All values for Streams 1 through 7 are weighted averages with respect to the Stream 1amounts.2. The mass balances for D4and D5were accomplished as follows:D4: Assign the amount missing from columns F and G (Row 2 minus Row 10) to a "D4/D5 Raw Material Reacted or Remaining in the Polymer" stream (Row 3).D5: Apportion the "Extra Lbs D5/Lbs D5Raw Material Consumed" by:- Adding the Reported lbs D5/ Lbs D5Raw Material Consumed for Streams 2 through 7.- Calculating the apportioned amount for each stream (Column H) by multiplying the values in Column G for each stream by the ratio of Cell G13 / Cell G12.- Calculating the mass-balanced values in Column I by adding Columns G and H for each stream.- Assigning the Lbs D5/yr calculated for Stream 2 to the "D4/D5Raw Material Reacted or Remaining in the Polymer" stream (Row 3) for D5.Key:= Not applicableWeightedAverage =Calculated as the sum of: the result of multiplying each stream by the corresponding Stream 1 for eachfacility and dividing by the sum of the Stream 1 values for the facilities that reported values for the streamfor which the weighted average was being calculatedERM31 January 2012FINAL

TABLE 6

POTENTIAL TECHNOLOGIES AND DISPOSAL OPTIONS FOR PUBLICLY OWNED TREATMENT WORKS 1 Silicones Environmental, Health and Safety Council

ERM 31 January 2012 Treatment

Type General Objective Technologies/Disposal Options

Removal of solids  Coarse screens for removal of coarse solids

 Grinding of solids afte r coarse-solid removal

 Sedimentation using primary clarifiers to remove settleable solids

Primary

Treatment Removal of oil and grease, petroleum products, and toxic compounds  Flow equalization

 Skimming

 Flocculation

 Pre-aeration

 Flotation

 Chemical precipitation

Secondary

Treatment Removal of organic compounds via biological treatment  Activated sludge (consisting of an aerated, comple tely-mixed basin and a clarifier; a portion of the sludge removed in the clarifier by settling is re turned to the aerated basin to improve organics removal by using already acclimated microorganisms)

 Aerated lagoons (no return sludge)

 Stabilization ponds (partially aerobic and partially anaerobic)

 Trickling filters (tanks filled with media where the microorganisms attach)

 Sequential batch reactors (similar to activated sludge, but operated on a batch basis)

 Constructed wetlands

Advanced

Treatment Removal of pathogens/viruses,
solids, nonbiodegradable organics, nutrients (nitrogen and phosphorus), volatile compounds (organics or ammonia), dissolved

solids  Chlorination

 Granular-medium filtration

 Chlorination

 Nitrification/denitrificatio n (removal of nitrogen)

 Addition of powdered activated carbon to aeration basins

 Chemical precipitation in activated sludge or separate vessels

 Carbon adsorption using granular activated carbon vessels

 Harvesting of algae in stabilization ponds

 Air stripping

 Chemical oxidation

 Reverse osmosis

 Ion exchange

 Membrane filtration

Sludge

Treatment Stabilization, removal of pathogens or viruses,

volume reduction  Storage

 Gravity or flotation thickening

 Digestion, aerobic or anaerobic, with or without energy recovery

 Chlorine oxidation

 Lime stabilization

 Heat treatment

 Chemical conditioning

 Disinfection

 Dewatering using vacuum filters, f ilter presses, horizontal belt filt ers, centrifuges, drying beds, or lagoons

 Thermal drying

 Composting

Liquid

Effluent Disposal Final Disposal  Discharge to surface waters or wetlands

 Injection into aquifers to replenish ground water

 Land treatment

 Reuse (agricultural and landscape irrigation, industrial processes, or toilet flushing)

Sludge Disposal Final Disposal  Beneficial use as fertilizer for prop erly treated sludge (“biosolids”)

 Landfill disposal

 Incineration, fuel blending, or thermal reduction followed by landfill disposal

 Reclamation of strip mines

 Lagoon disposal

Sources: A. Water Environment Federation (WEF) and Americ an Society of Civil Engineers (ASCE) (2011). Design of Municipal Wastewater Treatment Plants , WEF Manual of Practice No. 8, ASCE Manuals and Reports on Engineering Practice No. 76, 5 th Edition, McGraw Hill, New York, New York. B. Water Environment Federation (1996). Operation of Wastewater Treatment Plants, Manual of Practice 11 , 5 th Edition, Alexandria, Virginia.

____________ 1 Not intended to be an all-inclusive list.

# FIGURESFIGURE 1BLOCK FLOW DIAGRAM TEMPLATE FOR MANUFACTURERS OF D4OR D5Silicones Environmental, Health and Safety CouncilPrecursorProcessesVent / AbatementFugitive AirEmissionsReactionSeparationsStorage TanksLoading OperationsOn-site Processing1On-site LandfillOn-site WWTPOff-site LandfillOff-site WWTPStormwater Run-offWastewaterStorageNote:1. Further processing of products will bedetailed on a separate documentBlockFlowDiagram‐FormulatorofD4/D5SiteBoundary1StorageareaMixingequipmentPackagingequipmentPollutioncontrolequipment34A12FugitiveairreleasesWastewatertreatment/StorageareaA25FIGURE 2BLOCK FLOW DIAGRAM TEMPLATE FOR FORMULATORS OF D4OR D5Silicones Environmental, Health and SafetyStorageD4 / D5StorageIntermediatesStorageFinal PolymerStorageRecovered D4 D5StorageWastewaterReactorPolymerizationReactorPolymerizationRecoveryD4 / D5PurificationFinal PolymerAbatementD4 / D5Storm waterSolid WasteFugitive7654321Block Flow Diagram:Processor of D4/D5 with on-site WWTPTreatmentWastewaterTo Surface WatersTo Off-siteWasteManagementFIGURE 3BLOCK FLOW DIAGRAM TEMPLATE FOR PROCESSORS OF D4OR D5WITH ON-SITE WASTEWATER TREATMENT PLANTSilicones Environmental, Health and Safety CouncilStorageD4 / D5StorageIntermediatesStorageFinal PolymerStorageRecovered D4 D5StorageWastewaterReactorPolymerizationReactorPolymerizationRecoveryD4 / D5PurificationFinal PolymerAbatementD4 / D5Storm waterSolid WasteFugitive7654321Block Flow Diagram:Processor of D4/D5 with no on-site WWTPTo Off-site POTWTo Off-siteWasteManagementFIGURE 4BLOCK FLOW DIAGRAM TEMPLATE FOR PROCESSORS OF D4OR D5WITHOUT ON-SITE WASTEWATER TREATMENT PLANTSilicones Environmental, Health and Safety CouncilStorageD4 / D5StorageIntermediatesStorageFinal PolymerStorageRecovered D4 D5StorageWastewaterReactorPolymerizationReactorPolymerizationRecoveryD4 / D5PurificationFinal PolymerAbatementD4 / D5Storm waterSolid WasteFugitive7654321Block Flow Diagram:Processor of D4/D5 with on & off site WWTPTreatmentWastewaterTo Off-site POTWTo Off-siteWasteManagementFIGURE 5BLOCK FLOW DIAGRAM TEMPLATE FOR PROCESSORS OF D4OR D5WITH ON-SITE AND OFF-SITE WASTEWATER TREATMENT PLANTSSilicones Environmental, Health and Safety CouncilProcessEquipmentAirEmissionsAirborneVaporsBeneficialSludgeReuseSurfaceSoilVolatilizationHuman ReceptorsErosionRunoffSurfaceWaterVolatilizationSurfaceWaterDepositionSedimentsDirect ContactHuman ReceptorsSurfaceSoilAirInhalation of VaporsAirInhalation of ParticulatesReptiles, BirdsMammalsDirect ContactIngestion of AquaticFoodIngestion of WaterAquatic PlantsUptake from WaterInvertebrates,Amphibians, FishUptake from SoilIngestion of SoilIngestion of TerrestrialFood ItemsIngestion of Fruits,Vegetables, Meat, MilkTerrestrial PlantsReptiles, BirdsMammalsDirect ContactSoil InvertebratesHuman ReceptorsReptiles, BirdsMammalsAirInhalation of VaporsStorm WaterRunoffSolid WastefromOperations,ActivatedCarbonDisposalGroundWaterLandfillInfiltrationDispersionIngestion of Drinking WaterInhalation of Vapors whileShoweringHuman ReceptorsPRIMARYSOURCESPRIMARYRELEASEMECHANISMSSECONDARYSOURCESSECONDARYRELEASEMECHANISMSTERTIARYSOURCESTERTIARYRELEASEMECHANISMSMIGRATIONPATHWAYSEXPOSUREROUTESPOTENTIALRECEPTORSFIGURE 6GENERIC D4AND D5INDUSTRIAL CONCEPTUAL SITE MODEL FOR HUMAN ANDECOLOGICAL RECEPTORSSilicones Environmental, Health and Safety CouncilInvertebratesBenthic PlantsUptake from SedimentsAmphibians, FishIngestion of Benthic FoodIncomplete pathway; substance degradesrapidly in air, water, and surface soil andadsorbs strongly to soilPotentially complete pathwayKey:AirTreatmentEquipment,Storage andProcessVesselsWasteWaterTreatmentPlantHuman ReceptorsFINALSludgeTreatmentLandfill31 January 2012InfiltrationDepositionPlantsHuman ReceptorsTo 11FINALSite BoundaryMixing equipmentNote:(1) Values shown are weighted averagesbased on data from four companies.FIGURE 731 January 2012MASS BALANCE FOR FORMULATORS OF D5Silicones Environmental, Health and Safety Council1StorageareaMixing equipmentPackagingequipmentPollution controlequipment34A12Fugitive airreleasesWaste watertreatment/StorageareaA25Fugitive Air Emissions:64.2 lb/yr (0.00086%)Point Source Air Emissions:246 lb/yr(0.0033%)Activated Carbon Waste to FuelRecovery:1,380 lb/yr(0.018%)Product Mixed with D5:7,497,429 lb/yr (99.87%)Waste from Operations:4,451 lb/yr (0.059%)Waste Water to POTW or for Off-site Treatment:3,776 lb/yr (0.050%)D5to Storage Area:7,507,346 lb/yr31 January 2012FIGURE 8MASS BALANCE FOR PROCESSORS OF D4Silicones Environmental, Health and Safety CouncilStorageD4 / D5StorageIntermediatesStorageFinal PolymerStorageRecovered D4StorageWastewaterReactorPolymerizationReactorPolymerizationRecoveryD4PurificationFinal PolymerAbatementD4Storm waterSolid WasteFugitive7654321D4Raw MaterialConsumed:67,268,603 lb/yrPoint Source Air Emissions:91,626 lb/yr (0.14%)Fugitive Air Emissions:3,051 lb/yr (0.0045%)D4Raw MaterialReacted or Remainingin the Polymer):67,039,994 lb/yr(99.66%)Industrial Waste WaterDischarge to POTW orSurface Water:2,094 lb/yr (0.0031%)Solid Waste Disposalto Off-site WasteManagement:131,585 lb/yr (0.20%)Note:(1) Output values shown are weighted averages based onD4Raw Material Consumed data from six companies.FINALStorm Water Discharge toSurface Waters:253 lb/yr (0.00038%)31 January 2012FIGURE 9MASS BALANCE FOR PROCESSORS OF D5Silicones Environmental, Health and Safety CouncilStorageD5StorageIntermediatesStorageFinal PolymerStorageRecovered D5StorageWastewaterReactorPolymerizationReactorPolymerizationRecoveryD5PurificationFinal PolymerAbatementD5Storm waterSolid WasteFugitive7654321D5Raw MaterialConsumed:4,354,908 lb/yrPoint Source Air Emissions:5,477 lb/yr (0.13%)Fugitive Air Emissions:65 lb/yr (0.0015%)D5Raw MaterialReacted orRemaining inthe Polymer):4,323,882 lb/yr(99.29%)Industrial Waste WaterDischarge to POTW orSurface Water:379 lb/yr (0.0087%)Storm Water Discharge toSurface Waters:0.5 lb/yr (0.000011%)Solid Waste Disposalto Off-site WasteManagement:25,104 lb/yr (0.58%)FINALNote:(1) Output values shown are weighted averages based onD5Raw Material Consumed data from five companies.SewerPumpStationCoarseScreeningPrimaryClarifierSecondaryClarifierAerationBasinSludgeCollection,Blending,and StorageSludgePumpStationPumpStationAnaerobicDigestionFilterPressesStorage andTransferFugitive AirEmissionsDischarge toSurface WaterFugitive AirEmissionsBiosolidsLandApplicationKey:Mostly Liquid StreamMostly Sludge StreamAir StreamFIGURE 10GENERIC BLOCK FLOW DIAGRAMFOR POTWs RECEIVINGWASTEWATER CONTAINING D4OR D5Silicones Environmental, Health and Safety CouncilPOTW Publicly Owned Treatment Works1123Note: See Figure 11 for further information on Streams 1, 2, and 3.Chlorination31 January 2012Waste Gas BurnerFINAL2Fugitive AirEmissionsAirborneVaporsBiosolids LandApplicationSurfaceSoilVolatilizationErosionRunoffSurfaceWaterVolatilizationDepositionSedimentsDirect ContactHuman ReceptorsAirInhalation of VaporsAirInhalation of ParticulatesReptiles, BirdsMammalsDirect ContactIngestion of Aquatic FoodIngestion of WaterAquatic PlantsUptake from WaterInvertebrates,Amphibians, FishUptake from SoilIngestion of SoilIngestion of TerrestrialFood ItemsIngestion of Fruits,Vegetables, Meat, MilkTerrestrial PlantsReptiles, BirdsMammalsDirect ContactSoil InvertebratesHuman ReceptorsReptiles, BirdsMammalsAirInhalation of VaporsDischargeto SurfaceWaterInfiltrationDispersionGroundWaterIngestion of Drinking WaterInhalation of Vaporswhile ShoweringHuman ReceptorsPRIMARYSOURCESPRIMARYRELEASEMECHANISMSSECONDARYSOURCESSECONDARYRELEASEMECHANISMSMIGRATIONPATHWAYSEXPOSUREROUTESPOTENTIALRECEPTORSFIGURE 11GENERIC CONCEPTUAL SITE MODEL FOR HUMAN AND ECOLOGICALRECEPTORS FOR POTWs RECEIVINGWASTEWATER CONTAINING D4OR D5Silicones Environmental, Health and Safety CouncilInvertebratesBenthic PlantsUptake from SedimentsAmphibians, FishIngestion of Benthic FoodIncomplete pathway; substance degradesrapidly in air, water, and surface soil andadsorbs strongly to soilPotentially complete pathwayKey:13Human ReceptorsFINAL31 January 2012Ingestion of Amphibians, FishHuman ReceptorsDepositionPlantsNote: Primary Sources are shown on Figure 10.Human ReceptorsHuman Receptors

# Attachment 3 Table of SEHSC Member Company D 4 

# /D 5 

# Manufacturing, Processing, and Formulating Facilities in the U.S.Silicones Environmental, Health and Safety Council January 31, 2012 

### ATTACHMENT 3 SEHSC Member Company D4/D5 Manufacturing/Processing/Formulating Facilities in the U.S.*

Company Facility Name Address Facility Description Discharge (Direct/Indirect)

Bluestar Silicones

USA
Corporation Ventura Plant 320 W Stanley Avenue

Ven tura, CA 93001 D4 processor

D5 processor and

formulator Indirect

Dow Corning
Corporation Carrollton Plant 4770 Highway 42 East
Carrollton, KY 41008 D4 manufacturer and

formulator

D5 manufacturer and

formulator Direct

Greensboro Plant 2914 Patterso n Street
Greensboro, NC 27407 D4 processor and

formulator

D5 formulator Indirect

Auburn Plant 5300 11 Mile Road
Auburn, MI 48611 D4 formulator

D5 formulator Indirect

Healthcare Industries

Materials Site 1635 N Gleaner Road
Hemlock, MI 48626 D4 formulator

D5 formulator Indirect

Midland Plant 3901 S Saginaw Road
Midland, MI 48640 D4 processor

D5 processor Indirect

Elizabethtown Plant 760 Hodgenville Road
Elizabethtown, KY 42701 D4 processor

D5 processor Indirect

Evonik

Goldschmidt

Co rporation Hopewell Plant 914 East Randolph Road
Hopewell, VA 23860 D4 processor

D5 processor Indirect

Momentive Waterford Plant 260 Hudson River Road
Waterford, NY 12188 D4 manufacturer,
processor, and formulator

D5 manufacturer,
processor, and form ulator Direct

Sistersville Plant 3500 S State Route 2 Friendly, WV 26146 D4 processor

D5 processor Direct

Shin

- Etsu Silicones
of America, Inc. Shin

- Etsu Silicones of

America, Inc. 1150 Damar Drive
Akron, OH 55305 D5 formulator None

Shincor Silico nes, Inc. 1030 Evans Avenue Akron,

OH 55305 D4 processor None

Wacker Chemical
Corporation Wacker Chemical

Corporation 3301 Sutton Road
Adrian, MI 49221 D4 processor

D5 processor Direct

*This list focuses exclusively on facilities that manufacture, p rocess, or formulate D4 or D5 with associated potential wastewater discharges. For purposes of this list, process means facilities that react D4 or D5 to create other substances. Formulate means those facilities that mix/blend D4 or D5 to create products . Facilities that only import or store D4 or D5 are not included. No facility information is included for SiVance, LLC.