Page 2 of 51 

# Problem Formulation for the Environmental Fate, Ecological Risk, Endangered Species, and Drinking Water Assessments in Support of the Registration Review of Sodium

Metabisulfite and Sulfur Dioxide

Sodium m etabisulfite (CAS No. 7681

- 57

- 4) Sulfur dioxide (CAS No. 7446

- 09

- 5)

Prepared by:

Geoff rey Sinclair Ph.D., Biologist Larry Liu Ph.D., Chemist U. S. Environmental Protection Agency Office of Pesticide Programs Environmental Fate and Effects Division

Environmental Risk Branch V 1200 Pennsylvania Ave., NW

Mail Code 7507P Washington, DC 20460 Reviewed by: Joseph De C ant, Ec ologist Gabe Rothman, Environmental Scientist

Approved by: Mah T. Shamim, Ph

. D

. , Branch Chief

July 23 , 2013Page 3 of 51 

## 1. Executive summary

The Environmental Fate and Effects Division (EFED) has completed the preliminary problem

formulation for the ecological risk, environmental fate, endangered species, and drinking water assessments to be conducted as part of the registrat ion review of sodium metabisulfite and sulfur

dioxide . The problem formulation describes the methods planned to be used during the completion of drinking water and ecological r isk assessments in support of registration review

and provide s an ove rview of t he environmental fate, ecological effects , and potential risks

associated with the use of sodium metabisulfite and sulfur dioxide

. This document also

identifies uncertainties and additional studies that would be beneficial to conduct an ecological

risk assessment. Major findings include:

Clarification of Labels: Current labels do not have clear application information . In order to estimate exposure, this data will be assumed based on a conservative es timate. Adding a

maximum single application rate, maximum number of applications per year and a minimum application interval to labels would significantly reduce uncertainty in exposure estimates. Additionally, information on typical number of applicatio ns and application intervals in storage and shipping would be useful.

Environmental Fate Data: There are not any identified data needs for the environmental fate and transport of sodium metabisulfite and sulfur dioxide.

Ecological Effects Data: Since no significant sodium metabisulfite exposure is expected in the environment, ecological studies are not being requested at this time for sodium metabisulfite.

Three ecological studies are required to improve understand ing of the ecological impacts of

sulfu r dioxide release into the ecosystem

.

• Avian Acute Inhalation Toxicity Study with Bobwhite Quail (A Non

- Guideline Study): Sulfur dioxide has fumigant uses that may result in exposure to birds via off

- site atmospheric transport in the vapor phase . The acute effects to birds exposed to sulfur

dioxide are unknown. This is a non

- guideline study under the 40 CFR Part 158 data requirements.

• Honeybee Acute Vapor Phase (A Non

- Guideline Study): Sulfur dioxide has fumigant uses that may result in exposu re to listed terrestrial invertebrates via off

- site atmospheric transport of the vapor phase . The acute effects to listed terrestrial invertebrates exposed to

sulfur dioxide are unknown. Honeybee acute is a surrogate for endangered species

assessment for t errestrial invertebrates. This is a non

- guideline study under the 40 CFR Part 158 data requirements.

• Vegetative Vigor Vapor phase (A Non

- Guideline Study): Sulfur dioxide has fumigant uses that may result in exposure to terrestrial plants via off

- site at mospheric transport in the vapor phase

. This is a non

- guideline study under the 40 CFR Part 158 data requirements.Page 4 of 51 Current labels suggest that during fumigation of structures such as warehouses and storage containers for ships and airplanes, and vehicles such as trucks, vans and rail cars, sulfur dioxide is released to the outdoor atmosphere during the aeration phase. Preliminary calculations of potential exposure show that sulfur dioxide will be present in environmental ly relevant concentrations that may affect terrestrial non

- target organisms. Sulfur dioxide has a general

mode of action that indicates the chemical may have toxicity to terrestrial animal and plant species. No data are available to assess the toxicity of sulfur dioxide to terrestrial invertebrates,

birds , or terrestrial vegetation near release points. In the absence of such data, insufficient information exists to preclude concerns for direct toxic effect to non

- target terrestrial invertebrate, bird, and terrestrial plant species.Page 5 of 51 

## 2. Introduction

Sodium metabisulfite (CAS No. 7681

- 57

- 4) and s ulfur dioxide (CAS No. 7446

- 09

- 5) are grouped as inorganic sulfites registered as fungicides (USEPA 2007)

. End

- use inorganic sulfite products contain sulfur dioxide at 99.9 % to 100% an d sodium metabisulfite at 37.5 % to 98.5% respectively and are typically used to treat for Botrytis cinerea , the fungus which causes bunch rot, or gray mold disease on grapes.

The sodium metabisulfite products are composed of the anhydrous, solid ingredien t contained in

semi

- sealed pads which are added to containers holding grapes prior to shipping. The pads absorb moisture, and release low levels of sulfur dioxide in the range of 1

- 5 ppm. The Agency currently has 11 products with sodium metabisulfite ( PC Code: 111409) as the active ingredient.

The re are currently 3 products with sulfur dioxide ( PC Code: 077601) as the active ingredient.

S ulfur dioxide (SO 2 ) products are formulated as a compressed liquid that converts to a gas upon release. These products are used in cold

- storage warehouses, trucks, vans and train cars for post

harvest grape fumigation. Release of sulfur dioxide after fumigation of structures provides routes of exposure that may impact terrestrial non

- target organisms that include terrestr ial

invertebrates , mammals, birds and plants.

In addition to the fungicidal use against Botrytis cinerea , sulfur dioxide is also used in combination with carbon dioxide to treat for black widow spider on grapes in warehouse settings. The black widow spider treatment is not included on any sulfur dioxide product labels since it is used in conju n ction with car bon dioxide and included in carbon dioxide labels as permitted under a FIFRA 24(c) carbon dioxide registration (CA920007). Additional s ources of sulfur dioxide include the combustion of fossil fuels, smelting of sulfide ores, volcanic emissions, and other natural sources. Sulfur dioxide is also used to manufacture hydrosulfites, to bleach wood pulp and paper, to process, disinfect, and bleach food, for waste and water treatment, in metal and ore refining, and in oil refining (ATSDR

- MMG 2004).

Both sodium metabisulfite (21CFR §182.3766) and sulfur dioxide (21CFR §182.3862) are listed as GRAS (Generally Recognized as Safe) by the FDA (Food and Drug Administration) as preservatives in certain foods. Sodium metabisulfite is also used up to a concentration of 1 % as an antioxidant in hair care products and as a reducing agent in cosmetic formulations (CIR 2003). Sulfur dioxide is a criteria air pollutant regulated under the Clean Air Act (40 CFR Part 50).

EFED evaluated the most recent registration evaluation d ecision for sodium metabisulfite and

sulfur dioxide in association with the update d toxicity, exposure, and usage information to determine if sufficient data are available and if further updates are needed to support registration

review. The previous RED (2007) did not identify any risk concern s for terrestrial wildlife and aquatic organisms. In addition, sulfur dioxide use is not expected to result in significant exposure to drinking water resources. At the time of the RED (2007), environmental fate and e cological effects data for sulfur dioxide were not required or received because the pesticide’s uses are limited to indoor use and there were not any modeling efforts that demonstrated outdoor

exposure.Page 6 of 51 

## 3. Use Characterization

a. Sodium Metabisulfite

Sodium m etabisulfite is an inorganic sulfite which is used as a fungicide. Eleven products are currently registered for post

- harvest grape fumigation. Sodium metabisulfite is imbedded in the paper pad (7 g a

. i

. per pad). No more than one pad is placed in the pa cking container for each 18 lbs of table grapes. When solid sodium metabisulfite is mixed with water or absorbs moisture, it produces sulfur dioxide, which is toxic to fungal pathogens. Table 1 includes the use

information that was summarized from L UI S reports of the eleven registration numbers for

sodium metabisulfite

.

Table 1 . Uses Site and Application Information for S odium M etabisulfite

Use Group Crop/Site Max App

Rate

Unit /

Area Max Application

#/Year Max Application

Rat e/Year Minimum

Retreatment

INDOOR

FOOD (wrap) GRAPES depends

on fruit weight Unspecified Unspecified Unspecified

INDOOR

NON

FOOD (stickers) footwear,
clothing, luggage, handbags,
purses, wallets,

gloves, hats,
belts, leather
goods, sporting goods, furniture, gift and packing
boxes, carpets,
photo albums,

musical

instruments, toys, bracelets,
jewelry , dolls,
lamps 1

sticker
per 2

ft 2 Unspecified Unspecified Unspecified



## b. Sulfur Dioxide

Sulfur dioxide is a gas with a pungent and irritating smell. Three Section 3 products are currently registered ( 11195

- 1, 67799

- 3, and 8996

- 9 ). It is formulated as a liquid under pressure which turns into gas upon release

. It has antifunga l and antimicrobial properties and is used for thePage 7 of 51 control of mold caused by Botrytis cinerea on grapes during storage and transport. Sulfur dioxide is also used for sanitation of corks and barrels in wine industry. Sulfur dioxide use as a pesticide has not exceeded 100 tons per year throughout the entire state of California from 2008

to 2010 (USEPA 2013). This amount represents a minor source as defined by the Clean Air Act which defines any individual source which emits sulfur dioxide below 100 tons pe r year as de

minimis (NSR 1990). Table 2 lists the use information for sulfur dioxide that was summarized

from L UI S reports.

Table 2. Uses Site and Application Information for sulfur dioxide

Use Site (Application Method Type Description) Aerial and/or

Ground Application Identified by Equipment/ Label

Restriction Formulation MaxSingle Appl. Rate Max # Appl./Year Max Yearly Appl. Rate Min Appl.

Interval

COMMERCIAL

STORAGES/WAREHOUSE

S PREMISES 1 (stored commodity fumigation) Terminology for Equipment:

Ground PRESSURIZED

GAS 1% (v/v) gas

conc. i n the

chamber Unspecified Unspecified 7 days Terminology for

Restrictions: No

Restrictions

COMMERCIAL

TRANSPORTATION

FACILITIES

- FEED/FOOD

FULL (stored commodity fumigation) Terminology for Equipment:

Ground PRESSURIZED

GAS 1% (v/v) gas

conc. in the

chamber Unspecified Unspecified Unspecified Terminology for

Restrictions: No

Restrictions

FOOD PROCESSING PLANT EQUIPMENT (FOOD CONTACT) (stored

commodity fumigation) Terminology for Equipment:

Ground PRESSURIZED

GAS 1% (v/v) gas

conc. in the

chamber Unspecified Unspecified Unspecified Terminology for

Restrictions: No

Restrictions

GRAPES (stored commodity fumigation) Terminology for Equipment:

Ground PRESSURIZED

GAS 1% (v/v) gas

conc. in the

chamber Unspecified Unspecified 7 days Terminology for

Restrictions: No

Restrictions

GRAPES (stored commodity fumigation) Terminology for Equipment:

Ground PRESSURIZED

GAS 1% (v/v) gas

conc. in the

chamber Unspecified Unspecified Unspecified Terminology for

Restrictions: No

Restrictions

1 Labels specify that all fumigations inside warehouses and food processing plants occur in fumigation chambers within the buildings.

Fumigation should occur as soon after harvest as is practical. For fruit to be stored for extended periods, initial gassing should occur on the day of harvest and follow on a 7

- 10 day interval. For fruit being shipped to market soon after harvest, fumiga tion should be done before shipment, or in transit, if fruit has been gassed three or fewer times. For fruit gassed in the warehouse more than three times, 12 or more hours should be allowed to elapse before shipment. Seeded varieties may be fumigated o n a 7

- 10 day interval up to 20 times. Most seedless varieties may be fumigated on a 7

- 10 day interval up to 15 times, but the Thompson Seedless variety should notPage 8 of 51 be fumigated more than 12 times. For high frequency

- low dosage treatment: sulfur dioxide should occur as soon after harvest. For fruit to be stored for extended periods, initial gassing should occur on the day of harvest and follow at a three times per week interval (2 days, 2 days,

and 3 days). Seedless and seeded varieties may be fumigated on this high frequency, low dosage basis as long as they are in storage.



## c. Additional Sources of Sulfur Dioxide

The largest sources of SO 2 emissions are from fossil fuel combustion at power plants (73%) and other industrial facilities (20%). Smaller source s of SO 2 emissions include industrial processes such as extracting metal from ore, and the burning of high sulfur containing fuels by locomotives, large ships, and non

- road equipment. SO 2 is linked with a number of adverse effects on the respiratory syste m. The Clean Air Act requires EPA to set national ambient air quality standards for “criteria pollutants.” Currently, sulfur dioxide (SO 2 ) is one of five major pollutants that are listed as criteria pollutants.

Sulfur dioxide can cause acid rain that ser iously affects ecosystems. Acid rain is a major problem in the northern hemisphere, where trees and whole forests have been affected. Sulfur dioxide deposition can affect vegetation around industrial discharges and in cities. Lichens are good bio

- ind icators of pollution and do not tend to grow where there is sulfur dioxide in the air ( http://www.e pa.gov/airquality/sulfurdioxide )

. According to Office of Air and Radiation in EPA, sulfur dioxide is one of a group of highly reactive gasses known as “oxides of sulfur.”



## 4. Conclusions from Previous Risk Assessments

As part of the 2007 RED, the Environmental Fate and Effects Division (EFED) reported that the only environmental fate data potentially needed for sulfur dioxide would be a hydrolysis study; however, the Agency determined that the chemistry of sulfur dioxide is so well documented in the open literature that an additional study was not necessary (EPA, 1993b). Sodium metabisulfite dissolves in water and forms sodium cations, disulfite anions and sulfur dioxide (OECD, 2001) . Sodium metabisulfite was not deemed to pose a significant environmental or ecological risk due to its applications indoors and lack of exposure routes to non

- target organisms

. Based on the high vapor pressure of sulfur dioxid e , the use pattern (indoor food

- use) and limits established for sulfur dioxide release in this decision document, the Agency had no ecological risk concerns resulting from the pesticidal use of sulfur dioxide and sodium

metabisulfite.



## a. **Ecological Risk Asses sment** 

No ecological risk concerns resulting from the indoor use of sulfur dioxide and sodium

metabisulfite were identified in the 2007 RED (USEPA, 2007)

.



### b. **Drinking Water Exposure Assessments**Page 9 of 51 Based on the use pattern and fate characteristics of these chem icals as of the RED 2007, the Agency does not have any drinking water concerns for sulfur dioxide and sodium metabisulfite.



### c. **Clean Water Act Programs**

Sodium metabisulfi te and sulfur dioxide are not identified as a cause of impairment for any water

bodies listed as impaired under section 303(d) of the Clean Water Act

. No Total Maximum Daily Load (TMDL) criteria have been developed for sodium metabisulfite and sulfur dioxide with these applications

.



## 5. Environmental Fate and Transport

Sulfur dioxide is formu lated as liquid under pressure which turns into gas upon release. Sodium metabisulfite is an inorganic sulfite and is formulated as an anhydrous and solid active ingredient. When solid sodium metabisulfite is mixed with water or absorbs moisture, it prod uces sulfur dioxide, which is toxic to fungal pathogens.

The environmentally relevant parameters including b asic physical and chemical properties of

sodium metabisulfite and sulfur dioxide are presented in Table s 3 and Table 4

.Page 10 of 51 Table 3

. Chemical Properties and Environmental Fate Parameters of Sodium

Metabisulfite.

Common Name Sodium metabisulfite

PC Code 111409

Chemical Names

IUPAC Sodium metabisulfite

CAS Sodium metabisulfite

CAS Number 7681

- 57

- 4

Chemical

Structure

Molecular

Formula Na 2 S 2 O 5

Molecular Weight (g/mole) 190.1

SMILES Code [O

- ]S(=O)S(=O)(=O)[O

- ].[Na+].[Na+]

Color White

Physical State Free

- flowing crystalline

Odor Dry environment: odorless

Moist environment: slight sulfur odor

Boiling Point NA

Melting Point > 170 o C

Water Solubility 45% by wt. in water at 20 o CPage 11 of 51 Table 4

. Chemical Properties and E nvironmental Fate Parameters of Sulfur Dioxide.

Common Name Sulfur dioxide

PC Code 077601

Chemical Names

IUPAC Sulfur dioxide

CAS Sulfur dioxide

CAS Number 7446

- 09

- 5

Chemical Structure O=S=O

Molecular Formula SO2

Molecular Weight (g/mole) 64.07

SMILES Code O=S=O

Color Colorless

Physical State Gas at standard conditions

Odor Rotten eggs (strong)

Boiling Point

- 10 o C

Melting Point

- 72 o C

Water Solubility 11.9% by wt. in water at 15 o C and 760 mm Hg

Vapor Pressure 237.2 kPa



### a. **Transformation Products**

Sulfur dioxide is the transformation product of sodium metabisulfite. Sulfur dioxide will take

water and oxide to transform into sulfuric acid whic h will result in acid rain in the environment.

SO 2 + H 2 O + 1/2 O 2 → H 2 SO 4



### b. **Sulfur Dioxide Concentration in the Environment derived**
**from the AERSCREEN Model**

In this problem formulation, a Tier 1 model (AERSCREEN) was used to determine whether present labeled use patterns of sulfur dioxide would potentially contribute to ambient air concentrations of concern to mammalian species. The model estimates the "worst

- case" of 1

- hour concentrations for a single source, wit hout the need for hourly meteorological data, and also

includes conversion factors for the "worst

- case" 3

- hour, 8

- hour, 24

- hour, and annualPage 12 of 51 concentrations. AERSCREEN is intended to produce concentration estimates that are equal to or greater than the esti mates produced by other refined air dispersion model with a fully developed set of meteorological and terrain data, but the degree of conservatism may vary depending on the application. The detailed modeling information for mechanical and passive release can be found in Appendix 1. The modeling output from m echa nical release and passive release can be found in Appendix 2 and 3, respectively. According the current labels at 10,000 ppm on an estimated treatment facility with 25,000ft 3 spaces, the maximum co ncentration s in the first hour as a result of mechanical and passive release are 30.7 and 106.0 m g/m 3 , respectively (Table 5 ).

Table 5. AERSCREEN hour average air maximum concentration.

Aeration

Scenario Maximum

1

- Hour

Conc. (ug/m3) Scaled 3

- Hour Con c. (ug/m3) Scaled 8

- Hour Conc. (ug/m3) Scaled 24

- Hour Conc. (ug/m3) Scaled

Annual

Conc. (ug/m3)

Mechanical 3.07E+04 3.07E+04 2.76E+04 1.84E+04 0.31E+04

Passive 1.06E+05 1.06E+05 1.06E+05 1.06E+05 N/A



## 6. Receptors

The receptor is the biological entity that is exposed to the stressor (EPA, 1998)

. C onsistent with the process described in the Overview Document (EPA, 2004 ), a risk assessment uses a surrogate species approach in its evaluation of sodium metabisulfite and sulfur dioxide. Toxicological data generated from surrogate test species, which are intended to be representative of broad taxonomic groups, are used to extrapolate to potential effects on a variety of species (receptors) included under these taxonomic groupings.

Guideline toxicity data are not available for sodium metabisulfite or sulfur dioxide and there have not been any studies submitted to EFED. Limited mammalian data is available and was outlined in the 2007 RED. Generally a cute and chronic toxicity data fr om studies submitted by pesticide registrants along with the available open literature are used to evaluate the potential

direct effects of sodium metabisulfite and sulfur dioxide to the terrestrial receptors identified in

this section. This includes toxic ity data on the technical grade active ingredient, degradates, and when available, formulated products. The open literature studies are identified through EPA’s

ECOTOX database ( http://cfpub.epa.gov/ecotox/ ), whi ch employs a literature search engine for locating chemical toxicity data for aquatic life, terrestrial plants, and wildlife. The evaluation of both sources of data can also provide insight into the direct and indirect effects of sodium

metabisulfite and sulfur dioxide on biotic communities from loss of species that are sensitive to the chemical and from changes in structure and functional characteristics of the affected

communities.



## 7. Exposure Pathways of Concern

S odium metabisulfite and its subsequent transformation into sulfur dioxide will not be assessed since it is used in packaging and there are no t any anticipated major releases from facilities intoPage 13 of 51 the environment. The environmental fate properties and use patterns of direct applications of sulfur dioxide indicate that aeration of fumigated structures and subsequent atmospheric transport of elevated concentrations of sulfur dioxide represent potential exposure mechanisms of sulfur dioxide to terrestrial organisms. Due to building downwash, u pdrafts, and downdrafts, the primary exposure pathway s are 1) inhalation of sulfur dioxide by non

- target mammals , birds and terrestrial invertebrates, and 2) direct contact of sulfur dioxide on non

- target plant s. Due to lack of direct pathways and minimal contributions to deposition of acid rain , EFED does not anticipate any sign i ficant aquatic exposure.



## 8

. Risk Hypothesis

A risk hypothesis describes the predicted relationship among the stressor, exposure, and assessment endpoint response along with the rationale for their selection. For sulfur dioxide , the following ecological risk hypothesis is being employed for this ecological risk assessment:

Based on the application methods, mode of action, fate and transport, and the sensitivity of non

- target terrestrial species, sulfur dioxide has the potential to reduce survival, reproduction, and/or growth in non

- target mammals, birds, reptiles, terrestrial

- phase amphibians , terrestrial invertebrates and terrestrial plants when used in accordance with

the c urrent label. Non

- target organisms include federally

- listed threatened and endangered species, as well as non

- listed species.

Based on the current appl ication methods and fate and transport of sulfur dioxide, t here is no expectation of a complete exposure pathway for aquatic organisms and exposure of aquatic organisms is expected to be low

.



## 9. Analysis Plan

In order to address the risk hypothesis, the potential for hazardous effects on the environment is estimated. The use, environmental fate, a nd ecological effects of sulfur dioxide are characterized and integrated to assess the risks. This is accomplished using a risk quotient (ratio of exposure concentration to effects concentration) approach. Although risk is often defined as the likelihood and magnitude of hazardous ecological effects, the risk quotient

- based approach does not provide a quantitative estimate of likelihood and/or magnitude of an adverse effect. However, as outlined in the Overview Document (USEPA, 2004), the likelihood of e ffects to individual organisms from particular uses of sulfur diox i de is estimated using the probit dose

- response slope and either the level of concern (discussed below) or the actual calculated risk quotient

value.

This analysis plan will be revisited and may be revised at the time of registration risk assessment depending upon the data available in the open literature and the information submitted by the public in response to the opening of the Registration Review docket.



### a. **Stressors of Concern**Page 14 of 51 Based on the preliminary screening models in this Problem Formulation that indicate outdoor exposure of sulfur dioxide after release from fumigated structures, sulfur dioxide is expected to be the dominant stressor present in the environment. Additionally , the RED (2007) indicates that both terrestrial plants and animals are sensitive enough that modeled outdoor exposure may result in adverse impacts to non

- target communities. Uses of sodium metabisulfite are not expected to result in outdoor exposures si nce it is solely used in packaging applications.



### b. **Measures of Ecological**  **Exposure**

The exposure of the outdoor terrestrial environment to s ulfur dioxide will be assessed as passive release and as mechanical ventilation through leakage of sulfur dioxide from structures during treatment and uncontrolled aeration post

- treatment. The largest structures that are fumigated will contain the largest mass of sulf ur dioxide residues and will require the largest time for ventilation and aeration. Therefore, inhalation exposure in the near field outdoor environment will be

assessed modeling fumigations of different sized structures.

Sulfur dioxide emissions from al l treated structures must be quantified in order to determine estimated exposure concentrations (EECs) in the air. The temporal emissions profile from each outdoor release point will be entered into dispersion models to determine the acute EECs in the

env ironment. Given the dispersion due to turbulence and downwind transport, it is not anticipated that chronic exposures will be of concern from a single fumigation event. The temporal emissions profile will be developed from indoor monitoring data. The em issions from each building will be calculated based on the loss of sulfur dioxide mass over time within the

structure.

Maximum acute inhalation EECs will be determined in the near field area directly adjacent to treated structures using the PERFUM model ( Tier 2). PERFUM is parameterized by a time

series of emissions data. PERFUM considers these emission values in tandem with a robust statistical sampling of meteorological data from points within rings surrounding a treated field (usually 5 years of hourl y meteorological data). The current version of PERFUM processes estimated air concentrations from EPA’s previously recommended atmospheric dispersion model in the near field, the Industrial Source Complex Short

- Range Model, Version 3 (ISCST3). The

framew ork for PERFUM is illustrated in Figure 1 below. Estimated air concentrations are calculated and binned by percentile distributions within each ring and averaging time period. First, a peak one

- hour averaging period will be used to calculate air EECs. I f necessary, a higher averaging period equivalent to the exposure duration in toxicity studies will be used to characterize the RQs resulting from utilizing the one

- hour peak EECs. The highest 90 th
percentile estimated air concentration from all averaging periods from the receptor ring closest to the edge of the field will be considered as the upper

- bound EEC to determine the RQ. The PERFUM model is publically available on the web from the follow link: http://www.exponent.com/projectdetail.aspx?project=450 . For the risk assessment, the air exposure at ground level outside the treated structure will be evaluated considering meteorological conditions most vulnerable to the downward transpo rt of the plume (usually associated with light winds and stagnant conditions).Page 15 of 51 Figur e 1

. Illustration of the spatial and temporal aspects of the source to receptor configuration

in PERFUM. The wind rose (left) illustrates the frequency distribution of variations in wind speed and wind direction that PERFUM accounts for in the transport of the vapor plume from the treated source to receptors (right).



### c. **Measures of Ecological**  **Effects**

Current data suggest that during fumigation of structures such as warehouses and storage containers for ships and airplanes, and vehicles such as trucks, vans and rail cars, sulfur dioxide is released to the outdoor atmosphere during the aeration phase. S ince sulfur dioxide is highly volatile and is a gas at room temperature and standard pressure, inhalation and direct contact from vapor following structural fumigation is expected to be the major exposure pathway. Preliminary calculations of potential expo sure show that sulfur dioxide will be present in

environmental ly relevant concentrations that may affect non

- target terrestrial organisms. Sulfur dioxide has a general mode of action that indicates the chemical may have toxicity to terrestrial

invertebrat es, mammals, birds, and plant species. No data are available to assess the toxicity of

sulfur dioxide to terrestrial organisms near release points. In the absence of such data, insufficient information exists to preclude concerns for direct toxic effect t o non

- target terrestrial organisms

.



### a. **Effects to Aquatic Organisms**

Effects on aquatic organisms from the proposed uses of sodium metabisulfite and sulfur dioxide

are expected to be minimal due to 1) primarily indoor use s, and 2) the high vapor pressure at

r oom temperature of sulfur dioxide resulting in atmospheric transport after release into the

environment. Receptor Rings

Treated

FieldPage 1 6 of 51 

### b. **Effects to Terrestrial Organisms**

Table 6 and Table 7 provide a summary of the terrestrial taxonomic groups, and most sensitive surrogate species tested to characterize the potential acute and chronic ecological effects of

sodium metabisulfite and sulfur dioxide respectively

.

Table 6 . Summary of the Most Sensitive Endpoints from Terrestrial Toxicity Studies for Sodium

metabisulfite

Taxonomic

Group Study Type Surrogate Species Toxicity

Value

Acute Toxicity

Classification Source (all units

in terms of

measured

active ingredient)

Mammals Acute

Oral Laboratory

rat LD 50 = 1540 mg/kg Toxicity Category III TOXNET,

2005

( Rattus norvegicus ) LD 50 = 1131 mg/kg

- bw OECD,

2001

A few acute toxicity tests for sodium metabisulfite have been reported though none have been

submitted to EFED . The 96

- hour LC 50 was 100 mg/L for fish and the 72

- hr EC 50 for algae was 48.1 mg/L. An acute 48

- hr EC 50 for daphnids has been reported to be 88.76 mg/L and a chronic NOEC of >10 mg/L was reported. Due to lack of exposure, EFED is not requesting any data

effects data on sodium metabisulfite.Page 17 of 51 Table 7 . Summary of the M ost S ensitive E ndpoints from T errestrial T oxicity S tudies for S uflur

D ioxide

Taxonomic

Group Study Type Surrogate Species Toxicity

Value

Acute Toxicity

Classification 1 Source (all units in

terms of

measured

active ingredient)

Mammals Acute

Inhalation Guinea Pig LD50 = 1000ppm/20

hr; 130 ppm/154 hr

LD50 = 2620 mg/m3/20hr or 2.6 mg/L IV HSDB, 2005

Acute

Inhalation Mouse LD50 = 3000 ppm / 30 min (7.9 mg/ L / 30 min) IV NIOSH,

2004

Acute

Inhalation Mouse LD50 = 150 ppm / 847 hr; 1000 ppm / 4 hr (2.6 mg/L) IV HSDB, 2005

Acute

Inhalation Rat LD50 = 2520 ppm/ 1 hr or 1.65 mg/L; 2168 mg/m3; 20mg/m3/5 hr;

30 mg/m3 III NIOSH,

2004

Acute

Inhalation Guinea pig Lowest published LC:

1039 ppm/24hr (2.7

mg/L/24 hr) IV NIOSH,

2004

Concentration of sulfur dioxide as low as 1

- 2 ppm have been reported to cause severe stress to green plants (USEPA 2007). The LD 50 for a four hour acute exposure of a mouse and comparable exposure of a rat to sulfur dioxide has been reported to be 2821 and 2168 mg m - 3

. Current models of both different potential environmental exposures and on the abovePage 18 of 51 mammalian LD 50 s, suggest that levels of concern (LOC) may occur at intermediate release scenarios (Appendix 4),



### c. **Ecological Incidents**

The ecological incident information system (EIIS) is an OPP database that houses ecological incidents that have been reported to the Agency. When available, EIIS includes date and location of an incident, type and magnitude of effects observed in various species, use(s) of pesticides known or sus pected of contributing to the incident, and results of any chemical residue analysis or other analyses conducted during incident investigation. EIIS incidents are categorized according to the certainty that the incident resulted from pesticide exposure. The Avian Monitoring System (AIMS) is a database administered by the American Bird Conservancy

that contains publicly available data on reported avian incidents involving pesticides. Many of

the incidents listed in this database are also in the EIIS . The National Pesticide Information Center, the National Institute of Occupational Safety and Health (NIOSH), National Poison Control Centers, the California Department of Pesticide Regulation (CDPR) were also searched.

As of 17 April, 2013, review of EIIS and AIMS identified no ecological incidents involving

either sodium metabisulfite or sulfur dioxide

.



### d. **Additional Ecotoxicity Data**

Toxicity data requested in this problem formulation will be used to calculate risk quotients. Any

additional information s ubmitted by the registrant or found in the open literature prior to conduct

of the risk assessment will also be considered. The open literature studies are identified using

EPA’s ECOTOXicology database ( ECOTOX) ( USEPA, 2007 c ), which employs a literature search engine for locating chemical toxicity data for aquatic life, terrestrial plants, and wildlife. The evaluation of both sources of data can also provide insight into the direct and indirect effects

of pesticides on biotic commun ities from loss of species that are sensitive to the chemical s and from changes in structure and functional characteristic s of the affected communities.



### e

**. Drinking Water** 

Based on the use pattern ( i.e., indoor and pack a ging) and fate characteristics of t hese chemicals, the Agency does not have any drinking water concerns for sulfur dioxide and sodium

metabisulfite.



### f

**. Available Monitoring Data** 

The Agency is not aware of air monitoring conducted by federal and state agencies due to uses as a pesticide . I f any such data become available, this data will be considered in the assessment to

the extent that the data on sulfur dioxide is relevant to uses as a pesticide

.Page 19 of 51 

### 10. **Endangered Species Assessments**

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), the Agency will evaluate risks to federally listed threatened and/or endangered (listed) species from registered uses of pesticides in registration review

. The process for evaluating potential risks to listed species is furthe r described at http://www.epa.gov/oppfead1/endanger/litstatus/riskasses.htm

.



### 11. **Endocrine Disruptor Screening Program**

Sodium metabisulfite and sulfur dioxide were not included in the first group of 67 chemicals or the second group of 134 chemicals issued i n order to conduct Tier 1 EDSP testing. For additional information the EDSP program, visit http://www.epa.gov/endo/

.



### 12. **Preliminary Identification of Data Gaps** 

**a. Labels** 

Current data supplied suggests that labels do not have a maximum application rate, a maximum number of applications or a minimum application interval. In order to estimate exposure, this

data will be assumed based on a conservative estimate. Adding a maximum application rate, a maximum number of applications and a minimum application interval to labels would significantly reduce uncertainty in exposure estimates. Additionally, information on typical number of applicat ions and application intervals would be useful.



### b. **Environmental Fate**

The fate of sodium metabisulfite and sulfur dioxide in the environment is well documented.

Therefore there are not any data gaps that necessitate environmental fate studies i n support of a risk assessment

.



### c. **Effects**

There have not been any ecological effects studies submitted to EFED that offer data in support

of a risk assessment for sodium metabisulfite or sulfur dioxide. Due to the anticipated limited exposure of non

- target organisms to indoor uses of sodium metabisulfite, EFED is not requesting any data for sodium metabisulfite

. In contrast, sulfur dioxide is released into the external

environment . Available toxicity endpoints that have been evaluated for mam m als and modeling

scenarios of sulfur dioxide release in the environment , suggest that exposures from these releases may impact non

- target organisms in proximity to the treatment facilities . Consequently, three special studies of terrestrial organisms that may be sensitive to sulfu r dioxide have been

identified as necessary for a risk assessment . These studies include a non

- guideline honeybee inhalation, a non

- guideline avian inhalation study

, and a non

- guideline terrestrial plant study ofPage 20 of 51 vegetative vigor and are outlined below (T able 8

, 9

, 10 )

. Due to lack or exposure routes to aquatic ecosystems, EFED is not requesting any data on aquatic organisms at this time.

Avian Acute Inhalation (Bobwhite Quail)

Because sulfur dioxide is highly volatile and gaseous at room temperature and standard pressure, inhalation of vapor following structural fumigation is the major potential exposure pathway for

non

- target mammals and birds. Current data suggest that during sulfur dioxide fumiga tion of

structures , the gas is released to the outdoor atmosphere during the aeration phase. No data is available to the Agency regarding sulfur dioxide toxicity to avian species via inhalation. This test will provide an avian acute inhalation endpoint for assessing risks of off

- site movement via

atmo spheric transport of vapors. In the absence of such data, insufficient information exists to preclude concerns for direct toxic effects to non

- target birds

.

Honeybee Acute Toxicity (Vapor Phase)

Because sulfur dioxide is highly volatile and gaseous at room temperature and standard pressure, inhalation of vapor following structural fumigation is the major potential exposure pathway for

non

- target terrestrial invertebrates

. Current data suggest that during sulfur dioxide fumiga tion of

structures , the gas is released to the outdoor atmosphere during the aeration phase. No data is available to the Agency regarding sulfur dioxide toxicity to terrestrial invertebrates exposed to fumigant vapors

. The honeybee acute study is a surrogate for endangered spece s assessment for

terrestrial invertebrates. In the absence of such data, insufficient information exists to preclude

concerns for direct toxic effects to non

- target invertebrates

.

Terrestrial Plant Vegetative Vigor (Vapor Phase)

No quantitative data is available to the Agency regarding sulfur dioxide toxicity to plants. Exposure potential exists during the aeration phase following structural fumigation. Sulfur

dioxide has a general mechanism of action that indicates the chemical may have toxicity to plan t species upon contact. No data are available to assess the toxicity of sulfur dioxide to vegetation near release points. In the absence of such data, insufficient information exists to preclude

concerns for direct toxic effects to non

- target plant species.Page 21 of 51 Table 8

. Ecological Effects Data for Aquatic Animals exposed to Sulfur Dioxide

Guideline Description MRID Classification Data Gap? Comments

850.1075 Acute

freshwater fish toxicity None Not applicable No

Limited aquatic exposure is expected based

on the labeled

uses and the fate properties

of sulfur

dioxide (cold water

species)

Acute

freshwater fish toxicity None Not applicable No

(warm water

species)

Acute

estuarine/ None Not applicable No marine fish

toxicity

850.101 Acute toxicity to

freshwater

invertebrates None Not applicable No

850.1025 Acute

estuarine/

None Not applicable No marine

mollusk toxicity

850.1035 Acute

estuarine/

None Not applicable No marine

invertebrate

toxicity

850.13 Freshwater

invertebrate

life cycle None Not applicable No

850.14 Freshwater fish early life

stage None Not applicable NoPage 22 of 51 Table 9

. Ecological Effects Data for Terrestrial Animals exposed to Sulfur Dioxide

Guideline Description MRID Classification Data Gap? Comments

850.21 Avian acute oral toxicity(upland

game or waterfowl

species) None Not applicable No 1 1 Acute inhalation is the primary route of exposure; thus, acute oral/dietary/contact toxicity and reproduction studies

are not
recommended

2 Birds and insects could potentially be

exposed to sulfur

dioxide released

from treated

structures. Data have high value in reducing uncertainty

of risk. A study protocol should be

submitted to the Agency prior to conducting each study.

3 EFED will use a weight of evidence approach to consider

possible chronic

effects to birds since practi cal

considerations prevent requests of

chronic avian tests. Avian acute oral toxicity (passerine

species) None Not applicable No 1

Non

guideline Avian

inhalation

toxicity None Not applicable Yes 2 ,3

850.22 Avian dietary toxicity (upland game species) None Not applicable No 1

Avian dietary toxicity (waterfowl

species) None Not applicable No 1

850.23 Avian reproduction (upland game species) None Not applicable No 1

Avian reproduction

(waterfowl

species) None Not applicable No 1

850.302 Honeybee acute contact toxicity None Not applicable No 1

Non

guideline Honeybee acute toxicity None Not applicable Yes 2Page 23 of 51 Table 10

. E cological E ffects D ata for Plants Exposed to Sulfur Dioxide

Guideline Description MRID Classification Data Gap? Comments

Non

guideline Terrestrial plant Vegetative Vigor (Vapor Phase) None Not applicable Yes 2

1 Limited exposure is anticipated for

seeds. 850.4100 A Terrestrial plant toxicity (Tier I&II seedling emergence) None Not applicable No 1

850.4150 B Terrestrial plant toxicity (Tier I&II vegetative vigor) None Not applicable No 1

850.4500 C Aquatic plant growth (freshwater green alga) None Not applicable No 3 2 Data on suflur dioxide toxicity to plants have high value in reducing

uncertainty. A study protocol

should be

submitted to the Agency prior to conducting the study modifying exposure route of

a terrestrial vegetative vigor study. Aquatic plant growth (freshwater

diatom) None Not applicable No 3

Aquatic plant growth (saltwater diatom) None Not applicable No 3

3 Limited aquatic exposure is expected based on

the labeled uses

and the fate properties of

sulfur dioxide. 850.45 Aquatic plant growth (Cyanobacteria) None Not applicable No 3

850.44 Aquatic plant growth (vascular

plants) None Not applicable No 3

A As of July 2012 the Final Guideline 850.4100 contains both Tier I and Tier II test guidance (formerly 850.4100 and

850.4225, respectively).Page 24 of 51 B As of July 2012 the Final Guideline 850.4150 contains both Tier I and Tier II test guidance (formerly 850.4150 and

850.4250, respectively).

C As of July 2012 (formerly 850.4500)Page 25 of 51 

## 13. References

Agency for Toxic Substances and Disease Registry (ATSDR). 2004. Medical Management Guidelines (MMGs) for Sulfur Dioxide (SO 2 ). http://www.atsdr.cdc.gov/MHMI/mmg116.html

Cosmetic Ingredient Review (CIR) 2003. Final report on the safety assessment of sodium sulfite, pota ssium sulfite, ammonium sulfite, sodium bisulfite, ammonium bisulfite, sodium metabisulfite, and potassium metabisulfite. International Journal of Toxicology, 22 (Suppl 2): 63

- 88.

Hazardous Substances Data Bank (HSDB). 2005. Sulfur Dioxide. http://toxnet .nlm.nih.gov.

Hazardous Substances Data Bank (HSDB). 2005. Sodium Metabisulfite. http://toxnet.nlm.nih.gov.

International Agency for Research on Cancer (IARC). 1992, IARC Monographs; Vol 54.

Material Safety Data Sheet for Sulfur Dioxide. Printed 2005; Last updated 1996. BOC Gases. http://phyvirtual.nju.edu.cn/material/MSDS/G79.pdf

NIOSH (National Institute for Occupational Safety and Health. 2004. The Registry of

Toxic Effects of Chemical Substances: Sulfur Dioxide. http://www.cdc.gov/niosh/rtecs/ws4 56d70.html

OECD (Organization for Economic Co

- operation and Development) SIDS (Screening Information Data Set). 2001. Disodium disulphite.

NSR (Office of Air new Source Review Workshop Manual). 1990. http://www.epa.gov/NSR/ttnnsr01/gen/wkshpman.pdf

Reiss, R. and Giffin J., 2004. A Probablistic Exposure and Risk Model for Fumigant Bystander Exposures using Iodomethane as a Case Study”. Report prepared for the FIFRA Science Advisory Panel and sponsored by Arvesta Corporation.

US EPA. 1992. Memo to B ruce Sidwell, PM 53; Accelerated Reregistration Branch, Special Review and Reregistration Division from Douglas Urban, Acting Branch Chief; Ecological Effects Branch, Environmental Fate and Effects Division. Re: Phase 4 Review of Reregistration Case #405 6 for Sodium Bisulfite (DP Barcode D182472)

USEPA

. 1995. Screen3 Model User’s Guide, Washington, D.C. EPA/630/R

- 95/002F. September 1995. http://www.epa.gov/scram001/userg/screen/screen3d.pdf. Accessed

March 2009.Page 26 of 51 USEPA

. 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs. U.S. Environmental Protection Agency, Office of Prevention, Pesticides and Toxic Substances, Office of Pesticide Programs, Washington DC. January 23, 2004.

USEP A. 2007. Reregistration Eligibility Decision (RED). Inorganic Sulfites. Special Review and Reregistration Division. Office of Pesticide Programs.

US EPA. 2013. Biological and Economic Analysis Division (BEAD) Chemical Profile for Registration Revi ew: Sulfur Dioxide (077601). Issued by BEAD (in OPP, OCSPP, EPA)

on 4/11/2003.Page 27 of 51 

### Appendix 1

.

Sulfur Dioxide Release Scenarios Specified on Labels

Sulfur dioxide is used to treat food and post

- harvested commodities in fumigation chambers, trucks, vans, and railcars. Labels specify maximum application rates, or indoor concentrations of sulfur dioxide, which are maintained over periods of time for treatments inside the chambers. Fumigation chambers, trucks, and railcars have a maximum size of 10,000 cubic feet 1 . Labels all require mechanical, or forced, aeration following a treatment of the commodities in fumigation chambers. Mechanical aeration releases the fumigant outdoors from the treated structure through a stack or vent. However, this is no t necessarily required in truck, vans, or railcars as the. Therefore, passive aeration, involving the ventilation of treated structures via natural means such as opening of windows and doors to allow air to circulate around the building, can occur. There fore, exposure from passive and mechanical release scenarios will be quantified.

Critical parameters for active and passive scenarios are described below. The mechanical aeration scenario is a forced release from a stack. The passive aeration scenario i s ventilation resulting from natural flow through a building. Therefore, the release scenarios for mechanical aeration is partially defined by certain specifications for a stack from which the release occurs. However, no stack parameters are specified fo r a passive aeration scenario since release is assumed to occur throughout the entire area of the building.

• Mechanical Aeration Scenario

Table 1 1 . Mechanical Aeration Scenario

Release Parameter Value Justification Application Rate (lbs./1,000 ft. 3 ) 1.6 3 Maximum value from product

label Building Size (ft. 3 ) 10,000 CSX website 1

Building Area (ft. 2 ) 400 Consistent with HED Methyl

Bromide Assessment for 10,000 ft. 3 structure 2

Building Height (ft.) 25 Consistent with HED Methyl

Bromide Assessment for 10,000 ft. 3 structure 2

Stack Diameter (in.) 39.6 Consistent with HED Methyl

Bromide Assessment for 10,000 ft. 3 structure 2

Stack Height (ft.) 30 Consistent with HED Methyl

Bromide Assessment for 5 foot stack atop 25 foot

1 Fumigation chambers are assumed to possess similar size to railcars. Citation: http://www.csx.com/index.cfm/customers/equipment/railroad

- equipment/Page 28 of 51 Release Parameter Value Justification building 10,000 ft. 3 structure

2

Emission Rate (lb./hr) 18.3 Full mass release from 10,000

ft. 3 structure from one release point over one hour 3

Flow Rate (cfm) 166.67 1 air exchange per hour from 10,000 ft. 3 structure (consistent with HED Methyl

Bromide Assessment for 10,000 ft. 3 structure) 2 ,4

1 Citation: http://www.csx.com/index.cfm/customers/equipment/railroad

- equipment/

2 Emission Rate (lbs./hr) = Application Rate (lbs./ 1,000 ft. 3 ) x Structure Size (ft. 3 ) Duration of Release (hr.)

3 Methyl bromide HED risk assessment citation:

D awson, J. 2008. Second Addenda to the 2006 (DP Barcode 304623) Phase 5 Human Health

R isk Assessment for Commodity Uses. Office of Pesticide Programs. Washington, DC. (November 26, 2008) (EPA DP Barcode 304612).

4 Flow rate (ft. 3 /min) = Air exchange rate (air exchanges/hr.) x Structure Size (ft. 3 ) x hours 60

minutes

• Table 12

. Passive Aeration Scenario

Release Parameter Value Justification Application Rate (lbs./1,000 ft. 3 ) 1.6 3 Maximum value from product

label Building Size (ft. 3 ) 10,000 CSX website 1

Building Area (ft. 2 ) 400 Consistent with HED Methyl

Bromide Assessment for
10,000 ft. 3 structure 2

Building Height (ft.) 25 Consistent with HED Methyl

Bromide Assessment for 10,000 ft. 3 structure 2

Release Height (ft.) 12.5 Half building height for 10,000 ft. 3 structure consistent with HED Methyl Bromide

Assessment 2

Flux Rate (g /m 2

- s) 6.20 x 10 - 2 Full mass release from 10,000

ft. 3 structure from 400 ft. 2
building over one hour 3

1 Flux Rate (g/m 2

- sec) = Application Rate ( g/m 3 ) x Structure Size ( m 3 ) Duration of Release (sec.) x Structure Area (m 2 )

where the application rate = 1.63 lbs./1,000 ft 3 (26.18 g/m 3 ), V is the building volume =

10,000 ft. 3 (283.17 m 3 ), and A is the area = 400 ft. 2 (37.2 m 2 ).

2 Methyl bromide HED risk assessment citation:Page 29 of 51 D awson, J. 2008. Second Addenda to the 2006 (DP Barco de 304623) Phase 5 Human Health Risk Assessment for Commodity Uses. Office of Pesticide Programs. Washington, DC. (November 26, 2008) (EPA DP Barcode 304612).

AERSCREEN Description

The Agency’s recommended screening dispersion model for the near field, the American Meteorological Society/EPA Regulatory Screening Model (AERSCREEN), will be used to generate screening EECs for the various release scenarios. The Tier I analysis will consider the emission rates and release flow rates and stack paramet ers for the various mechanical release

scenarios for sulfur dioxide. Worst

- case meteorological conditions (light winds and stagnant conditions) and downwash 2 parameters are assumed to calculate peak air EECs, representing

one

- hour average concentrations. Documentation on the AERSCREEN model is available at http://www.epa.gov/scram001/dispersion_screening.htm . A schematic of release scenarios from fumigated structures and the related conce ptual model for ground

- level exposure is shown in Figure 2 . For purposes of this screening analysis, all ecological receptors of concern will assumed to be present directly downwind from the building at ground level.

AERSCREEN Modeling Analyses

The input parameter values used in AERSCREEN for the screening analysis of sulfur dioxide air exposure is shown in Table s 1 3 and 14 below for mechanical and passive release scenarios, respectively. All of the modeled release scenarios conservatively assume th at aeration is complete after one hour which results in maximized peak (one

- hour average) concentrations.

Table 13

. AESCREEN input parameter values for the mechanical release scenario of sulfur

dioxide

. Input Parameter Option/Value Notes

2 Downwash is defined as the downward flow often observed on the leeward side of buildings induced by wake turbulence. Pollutants released from buildings can often become embedded in downwash flows and wake cavities.Page 30 of 51 Input Parameter Option/Value Notes

English or Metric

Units E (English)

Source Type P ( Point ) Mechanical ventilation

Emission Rate (lbs./hr ) 16.3 Full mass release from 10,000

ft. 3 structure from one release point over one hour 1

Stack or Release

Height Above

Ground (ft.) 30 Default for 10,000 ft. 3 building size based on methyl bromide

HED assessment 2

Stack Diameter (in. ) 39.6 Default for 10,000,000 ft. 3
building size based on methyl

bromide HED assessment 2

Stack Temperature (°F) 0

- Equivalent to Ambient Temperature No stack temperatures specified, conservative assumption is non

buoyant source

Option for Flow

Rate or Flow Velocity 3 (Flow Rate ACFM)

Stack Exit Stream

Flow Rate

( f

3 / m in. ) 166.67 Based on 1

- hour full exchange of volume (air exchange rate = 1.0 air exchanges per hour) 3

Urban or Rural? R (Rural) Conservative default

Minimum

Distance to Ambient Air (ft.) 3.3 Conservative default

NO 2 Chemistry 1 (No chemistry/pollutant is not NO 2 ) Tracer gas

- NO

x emissions not

modeled

Include Building

Downwash? Y (Yes) Downwash is feasible downward transport mechanism for plume

in release scenarios

Use Pre

- Existing

BPIPPRM File? N (No) Downwash parameters to be input manually

Building Height (ft.) 25 Default for 10,000,000 ft. 3
building size based on methyl

bromide HED assessment 2

Maximum 20 Square building footprintPage 31 of 51 Input Parameter Option/Value Notes

Horizontal

Building Dimension (ft.) consistent with building heights specified above

Minimum

Horizontal

Building

Dimensi on (ft.) 20 Square building footprint consistent with building heights specified above

Maximum

Building Dimension Angle

to True North (degrees) 0

Conservative parameterization of building downwash

– stack located on the leeward edge of the building Direction of Stack

from Building Center (degrees) 0

Distance Between Stack and Building Center (ft.) 10

Terrain Heights? N (No) Only flat terrain considered

Maximum

Distance to Probe (m) 5,000 Default

- maximum feasible

distance for screen

Include Discrete Receptors N (No) Automated receptors sufficient

Flagpole Receptors N (No) Ground

- level concentrations

assumed

Source Elevation (ft.) 0 Stack base from ground release

assumed

Minimum Temperature (°F) - 10 Default

– typical national

temperature range

Maximum Temperature (°F) 100 Default

– typical national

temperature range

Minimum Wind Speed (m/s) 0.5 Minimum in model:

conservative default

Anemometer

Height (ft.) 33 Typical boundary layer reference height (10 meters)

Surface

Char acteristics Option 1 (Single User Specified Values)

Albedo 0.6 Bare surface assumed around

source 4

Bowen Ratio 3.0 Bare surface assumed aroundPage 32 of 51 Input Parameter Option/Value Notes

source 4

Surface Roughness Length (m) 0.001 Bare surface assumed around

source 4

1 Emission Rate (lbs./hr) = Application Rate (lbs./ft. 3 ) x Structure Size (ft. 3 ) Duration of Release (hr.)

2 Methyl bromide HED risk assessment citation:

D awson, J. 2008. Second Addenda to the 2006 (DP Barcode 304623) Phase 5 Human Health Risk Assessment for Commodity Uses. Office of Pesticide Programs. Washington, DC. (November 26, 2008) (EPA DP Barcode 304612).

3 Flow rate (ft. 3 /min) = Air exchange ra te (air exchanges/hr.) x Structure Size (ft. 3 ) x hours

60 minutes

4 Default values for bare soil assumed. Please refer to, “User’s Guide for the AERMOD

Meteorological Preprocessor (AERMET)”, (EPA, 2004) for further details.

Table 14

. AESCR EEN input parameter values for the passive release scenario of sulfur dioxide

. Input Parameter Option/Value Notes

English or Metric Units M (Metric) Source Type A ( Area )

Emission Rate (g/s ) 2.05 Emission rate input is based resulting flux rate

based on one

- hour complete release (6.20x

10 - 2 g/m 2

- s) x Area of Building Footprint (37.16

m 2 ) 1

Area of building footprint

for 10,000 ft. 3 building based on methyl bromide

HED assessment 2

Release Height Above Ground (m) 3.81 Release height of half the building size assumed

based on HED assessment 2

Height of building for

10,000 ft. 3 based on methyl bromide HED

assessment 2

Minimum Horizontal Building Dimension (m) 6.1 Square building footprint consistent with building heights specified abovePage 33 of 51 Input Parameter Option/Value Notes

Maximum Horizontal Building Dimension (m) 6.1 Square building footprint consistent with building heights specified above

Initial Vertical Dimension (m) 3.81 Equivalence to release height assumed

Urban or Rural? R (Rural) Conservative default

Minimum Distance to Ambient Air (m) 1 Conservative default

NO 2 Chemistry 1 (No chemistry/pollutant is

not NO 2 ) Tracer gas

- NO

x emissions

not modeled

Maximum Distance to Probe (m) 5,000 Default

- maximum

feasible distance for screen

Include Discrete Receptors N (No) Automated receptors

sufficient

Flagpole Receptors N (No) Ground

- level

concentrations assumed

Source Elevation (m) 0 Stack base from ground

release assumed

Minimum Temperature (K) 250 (Default) Default

– typical national

temperature range

Maximum Temperature (K) 310 (Default) Default

– typical national

temperature range

Minimum Wind Speed (m/s) 0.5 Minimum in model:

conservative default

Anemometer Height (m) 10 Typical boundary layer reference height

Surface Characteristics Option 1 (Single User Specified Values)

Albedo 0.6 Bare surface assumed

around source 3

Bowen Ratio 3.0 Bare surface assumed

around source 3

Surface Roughness Length (m) 0.001 Bare surface assumed

around source 3

1 Flux Rate (g/m 2

- sec) = Application Rate ( g/m 3 ) x Structure Size ( m 3 ) Duration of Release (sec.) x Structure Area (m 2 ) where the application rate = 1.63 lbs./1,000 ft 3 (26.18 g/m 3 ), V is the building volume =

10,000 ft. 3 (283.17 m 3 ), and A is the area = 400 ft. 2 (37.2 m 2 ).

2 Methyl bromide HED risk assessment citation:

D awson, J. 2008. Second Addenda to the 2006 (DP Barcode 304623) Phase 5 Human Health Risk Assessment for Commodity Uses. Office of Pesticide Programs. Washington, DC. (November 26, 2008) (EPA DP Barcode 304612).Page 34 of 51 3 Default values for bare soil assumed. Please refer to, “User’s Guide for the AERMOD

Meteorological Preprocessor (AERMET)” (EPA, 2004) for further details.Page 35 of 51 

### Appendix 2 

## . AE R SCREEN output values for the mechanical release

scenario of sulfur dioxide.

AERSCREEN 11126 / AERMOD 1206 05/06/13

08:11:36

TITLE: SO2

------------------- ---------------------------------------------------------- ***************************** STACK PARAMETERS

****************************

-----------------------------------------------------------------------------

SOURCE EMISSION RATE: 2.05 38 g/s 16.300 lb/hr

STACK HEIGHT: 9.14 meters 30.00 feet

STACK INNER DIAMETER: 1.006 meters 39.60 inches

PLUME EXIT TEMPERATURE: Ambient

PLUME EXIT VELOCITY: 0.099 m/s 0.32 ft/s

STACK AIR FLOW RATE: 167 ACFM

RURAL OR URBAN: RURAL

INITIAL PROBE DISTANCE = 5000. meters 16404. feet

----------------------------------------------------------------------------- *********************** BUILDING DOWNWASH PARAMETERS

**********************

-----------------------------------------------------------------------------

BUILDING HEIGHT: 7.6 meters 25.0 feet

MAX BUILDING DIMENSION: 6.1 meters 20.0 feet

MIN BUILDING DIMENSION: 6.1 meters 20.0 feet BUILDING ORIENTATION TO NORTH: 0. degrees

STACK DI RECTION FROM CENTER: 0. degrees

STACK DISTANCE FROM CENTER: 3.0 meters 10.0 feet

----------------------------------------------------------------------------- ************************** FLOW SECTOR ANALYSIS

*********** ****************Page 36 of 51 25 meter receptor spacing: 1. meters

- 5000. meters

-----------------------------------------------------------------------------

FLOW BUILD BUILD MAX 1

- HR DIST TEMPORAL SECTOR WIDTH LENGTH XBADJ YBADJ CONC (m) PERIOD

----------------------------------------------------------------------------- 10 7.07 7.07

- 6.54

- 0.53 0.2351E+05 50.0 ANN

20 7.82 7.82

- 6.78

- 1.04 0.2492E+05 50.0 ANN

30 8.33 8.33

- 6.81

- 1.53 0.2472E+05 50.0 ANN

40 8.59 8.59

- 6.63

- 1.96 0.2454E+05 50.0 ANN

50 8.59 8.59

- 6.26

- 2.34 0.2538E+05 50.0 ANN

60 8.33 8.33

- 5.69

- 2.64 0.2544E+05 50.0 ANN

70* 7.82 7.82

- 4.95

- 2.87 0.2557E+05 50.0 ANN

80 7.07 7.07

- 4.06

- 3.00 0.2518E+05 50.0 ANN

90 6.10 6.10

- 3.05

- 3.05 0.2120E+05 50.0 ANN

100 7.07 7.07

- 3.00

- 3.00 0.2431E+05 50.0 ANN

110 7.82 7.82

- 2.87

- 2.87 0.23 77E+05 50.0 ANN

120 8.33 8.33

- 2.64

- 2.64 0.2386E+05 50.0 ANN

130 8.59 8.59

- 2.34

- 2.34 0.2205E+05 50.0 ANN

140 8.59 8.59

- 1.96

- 1.96 0.2227E+05 50.0 A NN

150 8.33 8.33

- 1.52

- 1.52 0.2069E+05 50.0 ANN

160 7.82 7.82

- 1.04

- 1.04 0.1963E+05 50.0 ANN

170 7.07 7.07

- 0.53

- 0.53 0.1664E+05 75.0 ANN

180 6.10 6.10 0.00 0.00 0.1363E+05 100.0 ANN

190 7.07 7.07

- 0.53 0.53 0.1664E+05 75.0 ANN

200 7.82 7.82

- 1.04 1.04 0.1963E+05 50.0 ANN

210 8.33 8.33

- 1.53 1.53 0.2071E+05 50.0 ANN

220 8.59 8.59

- 1.96 1.96 0.2227E+05 50.0 ANN

230 8.59 8.59

- 2.34 2.34 0.2205E+05 50.0 ANN

240 8.33 8.33

- 2.64 2.64 0 .2386E+05 50.0 ANN

250 7.82 7.82

- 2.87 2.87 0.2377E+05 50.0 ANN

260 7.07 7.07

- 3.00 3.00 0.2431E+05 50.0 ANN

270 6.10 6.10

- 3.05 3.05 0.2120E+05 50.0 ANN

280 7.07 7.07

- 4.06 3.00 0.2518E+05 50.0 ANN

290 7.82 7.82

- 4.95 2.87 0.2557E+05 50.0 ANN

300 8.33 8.33

- 5.69 2.64 0.2544E+05 50.0 ANN

310 8.59 8.59

- 6.26 2.34 0.2538E+05 50.0 ANN

320 8.59 8.59

- 6.63 1.96 0.2454E+05 50.0 ANN

330 8.33 8.33

- 6.81 1.52 0.2472E+05 50.0 ANN

340 7.82 7.82

- 6.78 1.04 0.2492E+05 50.0 ANN

350 7.07 7.07

- 6.54 0.53 0.2351E+05 50.0 ANN

360 6.10 6.10

- 6.10 0.00 0.2054E+05 50.0 ANN

* = worst case flow sectorPage 37 of 51 ------ ----------------------------------------------------------------------- ********************** MAKEMET METEOROLOGY PARAMETERS

*********************

-----------------------------------------------------------------------------

MIN/MAX TEMPERATURE: 249.8 / 310.9 (K)

MINIMUM WIND SPEED: 0.5 m/s

ANEMOMETER HEIGHT: 33.000 meters

SURFACE CHARACTERISTICS INPUT: USER ENTERED

ALBEDO: 0.60

BOWEN RATIO: 3.00 ROUGHNESS LENGTH: 0.001 (meters)

METEOROLOGY CONDITIONS USED TO PREDICT OVERALL MAXIMUM

IMPACT

-------------------------------------------------------------

YR MO DY JDY HR

-- -- -- --- -- 10 01 26 26 01

H0 U* W* DT/DZ ZICNV ZIMCH M

- O LEN Z0 BOW EN ALBEDO REF WS

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

- 0.01 0.010

- 9.000 0.020

- 999. 11. 4.6 0.001 3.00 0.60 0.50

HT REF TA HT

- - - - - - - - - - -

33.0 249.8 2.0

ESTIMATED FINAL PLUME HEIGHT (non

- downwash): 7.3 meters

METEOROLOGY CONDITIONS USED TO PREDICT AMBIENT BOUNDARY

IMPACT

--------------------------------------------------------------

YR MO DY JDY HR

-- -- -- --- -- 10 01 26 26 01Page 38 of 51 H0 U* W* DT/DZ ZICNV ZIMCH M

- O LEN Z0 BOWEN ALBEDO REF WS

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

- 0.01 0.010

- 9.000 0.020

- 999. 11. 4.6 0.001 3.00 0.60 0.50

HT REF TA HT

- - - - - - - - - - -

33.0 249.8 2.0

ESTIMATED FINAL PLUME HEIGHT (non

- downwash): 7.3 meters

----------------------------------------------------------------------------- ************************ AERSCREEN AUTOMATED DISTANCES

********* *************

OVERALL MAXIMUM CONCENTRATIONS BY DISTANCE

-----------------------------------------------------------------------------

MAXIMUM MAXIMUM

DIST 1

- HR CONC DIST 1

- HR CONC (m) (ug/m3) (m) (ug/m3)

--------------------- ---------------------

1.01 0.2337E+05 2525.00 809.2

25.00 0.2148E+05 2550.00 803.9

50.00 0.2557E+05 2575.00 799.7

75.00 0.2172E+05 2600.00 795.6

100.00 0.1833E+05 2625.00 791.4

125.00 0.1567E+05 2650.00 787.3

150.00 0.1380E+05 2675.00 783.1

175.00 0.1239E+05 2700.00 779.0

200.00 0.1128E+05 2725.00 774.9

225.00 0.1027E+05 2750.00 770.7

250.00 9337. 2775.00 766.6

275.00 8479. 2800.00 762.6

300.00 7642. 2825.00 758.5

325.00 6886. 2850.00 754.4

350.00 6150. 2875.00 750.4

375.00 5442. 2900.0 0 746.3

400.00 4814. 2925.00 742.3

425.00 4331. 2950.00 738.3

450.00 4060. 2975.00 734.4

475.00 3904. 3000.00 730.4

500.00 3764. 3025.00 726.5

525.00 3626. 3050.00 722.6

550.00 3489. 3075.00 718.7Page 39 of 51 575.00 3353. 3100.00 714.8

600.00 3218. 3125.00 710.9

625.00 3084. 3150.00 707.1

650.00 2952. 3175.00 703.3

675.00 2827. 3200.00 699.5

700.00 2706. 3225.00 695.7

725.00 2587. 3250.00 692.0

750.00 2469. 3275.00 688.2

775.00 2353. 3300.00 684.5

800.00 2239. 3325.00 680.8

825.00 2128. 3350.00 677.2

850.00 2024. 3375.00 673.5

875.00 1953. 3400.00 669.9

900.00 1885. 3425.00 666.3

925.00 1822. 3450.00 662.8

950.00 1761. 3475.00 659.2

975.00 1704. 3500.00 655.7

1000.00 1650. 3525.00 652.2

1025.00 1599. 3550.0 0 648.7

1050.00 1551. 3575.00 645.3

1075.00 1505. 3600.00 641.9

1100.00 1481. 3625.00 638.5

1125.00 1462. 3650.00 635.1

1150.00 1444. 3675.00 631.7

1175.00 1425. 3700.00 628.7

1200.00 1407. 3725.00 625.7

1225.00 1389. 3750.00 622.7

1250.00 1371. 3775.00 619.7

1275.00 1353. 3800.00 616.8

1300.00 1336. 3825.00 613.8

1325.00 1319. 3850.00 610.9

1350.00 1302. 3875.00 608.0

1375.00 1285. 3900.00 605.1

1400.00 1269. 3925.00 602.2

1425.00 1253. 3950.00 599.3

1450.00 1237. 3975.00 596.5

1475.00 1222. 4000.00 593.6

1500.00 1206. 4025.00 590.8

1525.00 1191. 4050.00 588.0

1550.00 1178. 4075.00 585.2

1575.00 1166. 4100.00 582.5

1600.00 11 54. 4125.00 579.7

1625.00 1141. 4150.00 577.0

1650.00 1129. 4175.00 574.3

1675.00 1117. 4200.00 571.8

1700.00 1106. 4225.00 569.4Page 40 of 51 1725.00 1094. 4250.00 567.0

1750.00 1083. 4275.00 564.7

1775.00 1072. 4300.0 0 562.3

1800.00 1061. 4325.00 559.9

1825.00 1051. 4350.00 557.6

1850.00 1040. 4375.00 555.2

1875.00 1030. 4400.00 552.9

1900.00 1020. 4425.00 550.6

1925.00 1010. 4450.00 548.3

1950.00 1001. 4475.00 546.0

1975.00 990.9 4500.00 543.7

2000.00 981.4 4525.00 541.5

2025.00 972.0 4550.00 539.2

2050.00 962.8 4575.00 537.0

2075.00 953.7 4600.00 534.7

2100.00 944.7 4625.00 532.5

2125.00 935.8 4650.00 530.3

2150.00 927.0 4675.00 528.1

2175.00 918.4 4700.00 525.9

2200.00 909.9 4725.00 523.8

2225.00 901.5 4750.00 521.8

2250.00 893.2 4775.00 519.8

2275.00 885.0 4800.00 517.7

2300.00 876.9 4825.00 515.7

2325.00 869.0 4850.00 513.7

2350.00 861.1 4875.00 511.7

2375.00 853.4 4900.00 509.8

2400.00 845.8 4925.00 507.8

2425.00 838.3 4950.0 0 505.8

2450.00 830.8 4975.00 503.9

2475.00 823.5 5000.00 501.9

2500.00 816.3

-------------------------------------------------------------------- --------- ********************** AERSCREEN MAXIMUM IMPACT SUMMARY

*********************

-----------------------------------------------------------------------------

MAXIMUM SCALED SCALED SCALED SCALED

1

- HOUR 3

- HOUR 8

- HOUR 24

- HOUR ANNUAL

CALCULATION CONC CONC CONC CONC CONC PROCEDURE (ug/m3) (ug/m3) (ug/m3) (ug/m3) (ug/m3)

--------------- ---------- ---------- ---------- ---------- ---------- FLAT TERRAIN 0.3067E+05 0.3067E+05 0.2760E+05 0.1840E+05 3067.Page 41 of 51 DISTANCE FROM SOURCE 3.00 meters directed toward 70 degrees

IMPACT AT THE

AMBIENT BOUNDARY 0.2337E+05 0.2337 E+05 0.2104E+05 0.1402E+05 2337.

DISTANCE FROM SOURCE 1.01 meters directed toward 70 degreesPage 42 of 51 

### Appendix 3. 

## AE R SCREEN output values for the passive release

scenario of sulfur dioxide.

AERSCREEN 11126 / AERMOD 1206 05/06/13

09:05:16

TITLE: so2passive3

---------------------------------------------------------- ------------------- ****************************** AREA PARAMETERS

****************************

-----------------------------------------------------------------------------

SOURCE EMISSION RATE: 2.0500 g/s 16.270 lb/hr

AR EA EMISSION RATE: 0.551E

- 01 g/(s

- m2) 0.437E+00 lb/(hr

- m2)

AREA HEIGHT: 3.81 meters 12.50 feet

AREA SOURCE LONG SIDE: 6.10 meters 20.01 feet

AREA SOURCE SHORT SIDE: 6 .10 meters 20.01 feet

INITIAL VERTICAL DIMENSION: 3.81 meters 12.50 feet

RURAL OR URBAN: RURAL

INITIAL PROBE DISTANCE = 5000. meters 16404. feet

----------------------------------------------------------------------------- *********************** BUILDING DOWNWASH PARAMETERS

**********************

-----------------------------------------------------------------------------

BU ILDING DOWNWASH NOT USED FOR NON

- POINT SOURCES

----------------------------------------------------------------------------- ************************** FLOW SECTOR ANALYSIS

*************************** 25 meter receptor spacing: 1. meters

- 5000. meters

-----------------------------------------------------------------------------

MAXIMUM IMPACT RECEPTORPage 43 of 51 Zo SURFACE 1

- HR CONC RADIAL DIST TEMPORAL SECTOR ROUGHNESS (ug/m3) (deg) (m) PERIOD

----------------------------------------------------- 1* 0.001 0.5452E+05 45 1.0 ANN * = worst case diagonal

----------------------------------------------------------------------------- ********************** MAKEMET METEO ROLOGY PARAMETERS

*********************

-----------------------------------------------------------------------------

MIN/MAX TEMPERATURE: 250.0 / 310.0 (K)

MINIMUM WIND SPEED: 0.5 m/s

ANEMOMETER HEIGHT: 10.000 meters

SURFACE CHARACTERISTICS INPUT: USER ENTERED

ALBEDO: 0.60

BOWEN RATIO: 3.00 ROUGHNESS LENGTH: 0.001 (meters)

METEOROLOGY CONDITIONS USED TO PREDICT OVERALL MAXIMUM

IMPACT

---------------------------- ---------------------------------

YR MO DY JDY HR

-- -- -- --- -- 10 01 17 17 01

H0 U* W* DT/DZ ZICNV ZIMCH M

- O LEN Z0 BOWEN ALBEDO REF WS

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

- 0.05 0 .011

- 9.000 0.020

- 999. 13. 2.4 0.001 3.00 0.60 0.50

HT REF TA HT

- - - - - - - - - - -

10.0 310.0 2.0

METEOROLOGY CONDITIONS USED TO PREDICT AMBIENT BOUNDARY

IMPACT

--------------------------------------------------------------Page 44 of 51 YR MO DY JDY HR

-- -- -- --- -- 10 01 17 17 01

H0 U* W* DT/DZ ZICNV ZIMCH M

- O LEN Z0 BOWEN ALBEDO REF WS

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

- 0.05 0.011

- 9.000 0.020

- 999. 13. 2.4 0.001 3.00 0.60 0.50

HT REF TA HT

- - - - - - - - - - -

10.0 310.0 2.0

----------------------------------------------------------------------------- ************************ AERSCREEN AUTOMATED DISTANCES

**********************

OVERALL MAXIMUM CONCENTRATIONS BY DISTANCE

-----------------------------------------------------------------------------

MAXIMUM MAXIMUM

DIST 1

- HR CONC DIST 1

- HR CONC (m) (ug/m3) (m) (ug/m3)

--------------------- ---------------------

1.00 0.5452E+05 2524.99 2062.

25.00 0.5432E+05 2550.00 2046.

50.00 0.3542E+05 2575.00 2029.

75.00 0.2707E+05 2600.00 2012.

100.00 0.2226E+05 2625.00 1996.

125.00 0.1909E+05 2650.00 1981.

150.00 0.1680E+05 2675.00 1965.

175.00 0.1520E+05 2700.00 1950.

200.00 0.1381E+05 2725.00 1934.

225.00 0.1268E+05 2749.99 1920.

250.00 0.1175E+05 2775.00 1905.

274.99 0.1097E+05 2800.00 1890.

300.00 0.1030E+05 2825.00 1876.

325.00 9717. 2850.00 1862.

350.00 9206. 2875.00 1848.

375.00 8 753. 2900.00 1835.

400.00 8348. 2925.00 1821.

425.00 7983. 2950.00 1808.

450.00 7651. 2975.00 1795.

475.00 7350. 3000.00 1782.Page 45 of 51 500.00 7085. 3025.00 1770.

525.00 6840. 3050.00 1757.

549.99 6615. 3075.00 1 745.

575.00 6406. 3100.00 1733.

600.00 6211. 3125.00 1721.

625.00 6030. 3150.00 1709.

649.99 5860. 3175.00 1697.

675.00 5701. 3200.00 1686.

699.99 5552. 3225.00 1674.

725.00 5411. 3250.0 0 1663.

749.99 5278. 3275.00 1652.

775.00 5152. 3300.00 1641.

800.00 5034. 3325.00 1630.

825.00 4921. 3350.00 1620.

850.00 4815. 3375.00 1609.

875.00 4713. 3400.00 1599.

900.00 4616. 3425.00 1589.

924.99 4523. 3450.00 1578.

950.00 4435. 3475.00 1568.

975.00 4350. 3500.00 1559.

1000.00 4269. 3525.00 1549.

1024.99 4191. 3550.00 1539.

1050.00 4116. 3575.00 1530.

1075.00 4044. 3600.00 1520.

1100.00 3975. 3625.00 1511.

1125.00 3908. 3650.00 1502.

1150.00 3844. 3674.99 1493.

1175.00 3782. 3700.00 1484.

1200.00 3722. 3725.00 1475.

1224.99 3664. 3750.00 1466.

1250.00 3608. 3775.00 1458.

1275.00 3554. 3800.00 1449.

1300.00 35 02. 3825.00 1441.

1325.00 3451. 3850.00 1432.

1350.00 3402. 3875.00 1424.

1375.00 3354. 3900.00 1416.

1400.00 3308. 3925.00 1408.

1425.00 3263. 3950.00 1400.

1450.00 3220. 3975.00 1392.

1475.00 3177. 4000.0 0 1384.

1500.00 3136. 4025.00 1376.

1525.00 3096. 4050.00 1368.

1550.00 3057. 4075.00 1361.

1574.99 3019. 4100.00 1353.

1600.00 2982. 4125.00 1346.

1625.00 2946. 4150.00 1339.Page 46 of 51 1650.00 2911. 4175.00 1331.

1675.00 2877. 4200.00 1324.

1700.00 2843. 4225.00 1317.

1725.00 2811. 4250.00 1310.

1750.00 2779. 4275.00 1303.

1774.99 2748. 4300.00 1296.

1800.00 2718. 4325.00 1289.

1825.00 2688. 4350.00 1283.

1850.00 2659. 4375.00 1276.

1875.00 2630. 4400.00 1269.

1900.00 2603. 4425.00 1263.

1924.99 2576. 4450.00 1256.

1950.00 2549. 4475.00 1250.

1975.00 2523. 4500.00 1243.

2000.00 2498. 4525.00 1237.

2025.00 2473. 4550.00 1231.

2050.00 2448. 4575.00 1225.

2075.00 2424. 4600.00 1218.

2100.00 2401. 4625.00 1212.

2125.00 2378. 4650.0 0 1206.

2150.00 2355. 4675.00 1200.

2175.00 2333. 4700.00 1195.

2200.00 2311. 4725.00 1189.

2225.00 2290. 4750.00 1183.

2250.00 2269. 4775.00 1177.

2275.00 2249. 4800.00 1172.

2300.00 2229. 4825.00 1166.

2325.00 2209. 4850.00 1160.

2350.00 2189. 4875.00 1155.

2375.00 2170. 4900.00 1149.

2400.00 2151. 4925.00 1144.

2425.00 2133. 4950.00 1138.

2449.99 2115. 4975.00 1133.

2475.00 2097. 5000.00 1128.

2500.00 2080.

-------------------- --------------------------------------------------------- ********************** AERSCREEN MAXIMUM IMPACT SUMMARY

*********************

-----------------------------------------------------------------------------

3

- hour, 8

- hour, and 24

- hour scaled concentrations are equal to the 1

- hour concentration as referenced in SCREENING PROCEDURES FOR ESTIMATING THE AIR QUALITYPage 47 of 51 IMPACT OF STATIONARY SOURCES, REVISED (Section 4.5.4) Report number EPA

- 454/R

- 92

- 019 http://www.epa.gov/scram001/guidance_permit.htm under Screening Guidance

MAXIMUM SCALED SCALED SCALED SCALED

1

- HOUR 3

- HOUR 8

- HOUR 24

- HOUR ANNUAL

CALCULATION CONC CONC CONC CONC CONC PROCEDURE (ug/m3) (ug/m3) (ug/m3) (ug/m3) (ug/m3)

--------------- ---------- ---------- ---------- ---------- ---------- FLAT TERRAIN 0.1062E+06 0.1062E+06 0. 1062E+06 0.1062E+06 N/A

DISTANCE FROM SOURCE 5.01 meters

IMPACT AT THE

AMBIENT BOUNDARY 0.5452E+05 0.5452E+05 0.5452E+05 0.5452E+05 N/A

DISTANCE FROM SOURCE 1.00 metersPage 48 of 51 

### Appendix **4**

**.** Risk Quotients calculated fro m passive and mechanical r elease scenarios based

on scaled 3

- Hour concentration AERSCREEN model. The level of concern for listed species is risk quotient (RQ) of 0.1.

1 RELEASE

Concentration Mouse Rat

LC50 (mg/m3) 2821 2168

Mechanical (mg/m3) 30.70 30.70

Passive (mg/m3) 106.00 106.00

RQ Mechanical 0.01 0.01

RQ Passive 0.04 0.05

3 SIMULTANEOUS

RELEASES

Concentration Mouse Rat

LC50 (mg/m3) 2821 2168

Mechanical (mg/m3) 92.10 92.10

Passive (mg/m3) 318.00 318.00

RQ Mechanical 0.03 0.04

RQ Passive 0.11 0.15

5 SIMULTANEOUS

RELEASES

Concentration Mouse Rat

LC50 (mg/m3) 2821 2168

Mechanical (mg/m3) 153.50 153.50

Passive (mg/m3) 530.00 530.00

RQ Mechanical 0.05 0.07

RQ Passive 0.19 0.24Page 49 of 51 

### Appendix **5**

**. Data Call** 

**- In tables for non** 

**- guideline studies of sulfur** 
**dioxide**

Guideline Number: Non

- guideline Study Title: Terrestrial Plant Vegetative Vigor (Vapor Phase S pecial S tudy ) Rationale for Requiring the Data Current data suggest that during fumigation of structures such as warehouses and storage containers for ships and airplanes, and vehicles such as trucks, vans and rail cars, sulfur dioxide is released to the outdoor atmosphere during the aeration phase. Preliminary calculatio ns of potential exposure show that sulfur dioxide will be present in environmental relevant concentrations that may affect non

- target organisms. Sulfur dioxide has a general m ode of action that indicates the chemical may have toxicity to plant species. No data are available to assess the toxicity of sulfur dioxide to vegetation near release points. In the absence of such data, insufficient information exists to preclude concerns for direct toxic effect to non

- target plant species. Practical Utility of t he Data

How will the data be used? With this study, the Agency will be able to assess risks to endangered and other non

target plants downwind from release points of sulfur dioxide. If the terrestrial plant special study shows that sulfur dioxide exceeds the Agency’s level of concern for

f ederally

- listed or other terrestrial plant species, the Agency may be able to use this data to mitigate risks.

How could the data change the Agency’s decision or impact the Agency’s future

decision

- making? If future endangered species risk assessments a re performed without these data, the Agency would assume that sulfur dioxide may affect endangered terrestrial plant species directly and the endangered species that depend on these plants. Use of sulfur dioxide may need to be restricted in areas where en dangered species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in complying with the Endangered Species Act and could result in use restrictions for sulfur dioxide that are unnecessarily severe.Page 50 of 51 Guideline Number: Non

- guideline Study Title: Avian Acute Inhalation (Bobwhite Quail) Rationale for Requiring the Data Current data suggest that during fumigation of structures such as warehouses and storage containers for ships and airplanes, and vehicles such as trucks, vans and rail cars, sulfur dioxide is released to the outdoor atmosphere during the aeration phase. Preliminary calculations of potential exposure show that sulfur dioxide will be present

in environmental relevant concentrations t hat may affect non

- target organisms. Since sulfur dioxide is highly volatile and is a gas at room temperature and standard pressure, inhalation of vapor following structural fumigation is the major exposure pathway for

non

- target mammals and birds. No data are available to assess the toxicity of sulfur dioxide to avian species near release points

. In the absence of toxicity data, insufficient information exists to preclude concerns for direct toxic effects to non

- target birds.

Practical Utility of th e Data

How will the data be used? With this study, the Agency will be able to assess risks to endangered and other non

target avian species near release points of sulfur dioxide. If the avian inhalation study

shows t hat sulfur dioxide exceeds the Agency’s level of concern for federally

- listed or other terrestrial avian species, the Agency may be able to use this data to mitigate risks.

How could the data change the Agency’s decision or impact the Agency’s future

decision

- making? If future endang ered species risk assessments are performed without these data, the Agency would assume that sulfur dioxide may affect endangered avian species. Use of sulfur dioxide may need to be restricted in areas where endangered species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in complying with the Endangered Species Act and could result in use restrictions for sulfur dioxide that are unnecessarily severe.Page 51 of 51 Guideline Number: Non

- guideline Study Title : Honeybee Acute Toxicity (Vapor Phase) Rationale for Requiring the Data Current data suggest that during fumigation of structures such as warehouses and storage containers for ships and airplanes, and vehicles such as trucks, vans and rail cars, sulfur dioxide is released to the outdoor atmosphere during the aeration phase. Preliminary calculations of potential exposure show that sulfur dioxide will be present

in environmental ly relevant concentrations that may affect non

- target organisms. Since

sulfur dioxide is highly volatile and is a gas at room temperature and standard pressure, inhalation of vapor following structural fumigation is the major exposure pathway for

non

- target terrestrial invertebrates that reside above the soil . No data are availabl e to assess the toxicity of sulfur dioxide to non

- target invertebrates near release points. The honeybee acute test is a surrogate for endangered species assessment for terrestrial

invertebrates. In the absence of toxicity data, insufficient information exists to preclude

concerns for direct toxic effects to non

- target insects.

Practical Utility of the Data

How will the data be used? With this study, the Agency will be able to assess risks to endangered and other non

target terrestrial insect species near release points of sulfur dioxide. If the honeybee acute vapor phase study shows that sulfur dioxide exceeds the Agency’s level of

c oncern for federally

- listed or other terrestrial avian species, the Agency may be able to use this data to mitigate risks.

How could the data change the Agency’s decision or impact the Agency’s future

decision

- making? If future endangered species risk a ssessments are performed without these data, the Agency would assume that sulfur dioxide may affect endangered terrestrial insect species. Use of sulfur dioxide may need to be restricted in areas where endangered species could be exposed. The lack of the se data will limit the flexibility the Agency and registrants have in complying with the Endangered Species Act and could result in use restrictions for sulfur dioxide that are unnecessarily severe.