Page 1 of 5 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, DC 20460

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION

June 2 9 , 2011

MEMORANDUM:

Subject: Occupational Exposure Assessment for the Proposed Use of Ammonium Sulfate as Nalco 60620 in Pulp and Paper Mill Water Systems

PC Code: 005601 DP Barcode: D3 91275

Decision No.: 443828 Registration No.: 1706

- EUN

Petition No.: NA Regulatory Action: Product Registration

– Section 3 Risk Assess Type: Single Chemical Case No.: NA

TXR No.: NA CAS No.: 7783

- 20

- 2

MRID No.: 48340810 , 48461201 40 CFR: NA

To: Tracy Lantz, Product Manager, Team 33 Regulatory Management Branch I Antimicrobials Division (7510P)

From: Timothy C. Dole, CIH, Industrial Hygienist Risk Assessment and Science Support Branch (RASSB) Antimicrobials Division (7510P)

Thru: Timothy Leighton, Senior Scientist Risk Assessment and Science Support Branch (RASSB) Antimicrobials Division (7510P)

And

Nader Elkassabany, Branch Chief Risk Assessment and Science Support Branch (RASSB) Antimicrobials Division (7510P)Page 2 of 5 Introduction

The purpose of this memo is to evaluate the potential for occupational exposure and risk resulting from the proposed use of ammonium sulfate to treat pulp and paper mill water systems. This evaluation is based on the proposed label, an exposure evaluation submitted by Nalco

, air sample results provided by Nalco and information from the literature.

Use Information

Nalco 60620 is proposed for the control of microbial contamination in pulp and paper mill water systems. It contains 20 percent ammonium sulfate as the active ingredient and it is used in conjunction with sodium hypochlorite (typically 12.5%) in a proprietary delivery system (OxiPro) to produce monochloramine on site. The OxiPro delivery system controller ensures the automatic production of the dilute chloramine solution, controls the optimization of the production process, and ensures the adequate dosing into the water requiring treatment. The treatment can be administered using the slug, intermediate or continuous feed methods. The speci fied dose is 1 to 10 ppm available chlorine for both initial and subsequent treatments.

Exposure Assessment

As discussed in MRID 483408

- 10 “Nalco 60620

- Discussion of Applicator Exposure Data Requirement”, the OxiPro feed system is a closed system. T he chemicals are supplied in refillable portable totes, semi

- bulk containers, or from tanker trucks and are transferred through hoses to storage tanks. The chemicals are then transferred from the storage tanks into the OxiPro feed system and then the mix ture is pumped into the mill process. Based on this information it is anticipated that exposures to the precursor chemicals ammonium sulfate and sodium hypoch l orite would be minimal and would not trigger any risk concerns. Although not specifically stated on the label, it is anticipated that the reaction will be controlled by maintaining alkaline pH to enhance the production of monochloramine, which is only slightly volatile from water while minimizing the production of trichloramine (also called nit rogen trichloride) , which is highly volatile. As discussed in Kovacic et al., 1970, the product of the reaction of ammonia with chlorine or hypochlorous acid is chloramine when the pH >8.

Air Sampling Data for Nitrogen Trichloride (NCl 3

Nalco has submitted air sampling data (MRID 484612

- 01) where NCl 3 air concentrations as total chloramines were measured in one paper mill that w as using Nalco 606 20 as a biocide (Mill #1) and in another paper mill that was using ammonium bromide as a biocide (Mill #2)

. Additional information regarding the characteristics of each mill was also reported in a letter (Mann, 2011b) from the registrant’s representative and is included in Table 1. It should be noted that the location and production rate of each mill was reported but is not included in Table 1

because it is confidential business information. ) in Paper MillsPage 3 of 5 Table 1

– Characteristics of Paper Mills Sampled in MRID 484612

- 01

Characteristic Mill #1 Mill #2

Location Confidential Confidential Type of Paper

Produced Light weight coated

Coated free sheet

Uncoated free sheet Coated free sheet

Production Rate Confidential Confidential

Ventilation Design Roof exhaust fans. Moisture capture from exhaust fans in the dryer section

. Roof exhaust fan. Pocket ventilators in the dryer section for moisture control

. Building

Volume 12,000,000 cubic feet 6,000,000 cubic feet

Airflow Not Reported 580, 000 CFM (5.8 ACH)

The samples were collected by either an IH C onsul t ant ( M ill #1) or by a Nalco Indu s trial Hygienist (Mill #2) using a sampling method based on Hery, 1995. This me thod includes a sampling cassette that contain s a PTFE pre

- filter to trap aerosols containing nonvolatile amines

, such as monochloramine, and chloride compounds followed by prim ary and backup quartz fiber

filter s impregnated with sodium carbonate and diarsenic trioxide to trap NC l 3

. Samples were collected at a flow rate of 1.0 liter per minute for 1 28 to 177 minutes at Mill #1 and for 240

minutes at Mill #2. The samples were an alyzed by Galson Laboratories, which is accredited by the American Industrial Hygi e ne Association, using i on chromatography in accordance with an in

- house method based on Hery,1995 . This method detects total chlo r amines and has a limit of detection of 6 ug per filter.

The results of the air sampling are summarized in Table 1 . T hese results indicate that for Mill #1, NCl 3 air concentrations exceeded 0.011 or 0.14 mg/m 3 for samples 2AR, 2ARB and

2ARC while for the remaining sa mples , NCl 3 did not exceed the limit of detection that ranged

from 0.03 to 0.0 5 mg/m 3

. The actual air concentration for samples 2AR, 2ARB and 2ARC is unknown because significant breakthrough was detected on the backup treated filter. In M ill #2

, the results ranged from non

- detect to 0.13 mg/m 3 and no breakthrough occurred though it was noted that heavy misting occurred at L ocation #1 and significant eye irritation was experienced

at L ocation #2.Page 4 of 5 Table 1

– Nitrogen Trichloride Air Sample Data Submitted by Nalco

Mill (Date) Location Sample

ID Duration (Minutes) Result (mg/m 3 ) Treatment

Mill #1 (10/14/08) Paper Machine

– location confidential 2AR 135 > 0. 14* Nalco 606 20 ( Ammonium

Sulfate ) Paper Machine

– location confidential 2ARB 153 > 0. 11* Paper Machine

– location confidential 2ARC 152 > 0. 14* Paper Machine

– location confidential 2CRFA 148 <0.0 4 Paper Machine

– location confidential 2CRFB 177 <0.0 3 Paper Machine

– location confidential 2CRFC 136 <0.0 4 Paper Machine

– location confidential 2SPOFA 134 <0.04 Paper Machine

– location confidential 2SPOFB 160 <0.04 Paper Machine

– location confidential 4RSA 127 <0.0 5 Paper Machine

– location confidential 4RSB 151 <0.04 Paper Machine

– location confidential 4TRSA 128 <0.0 5 Paper Machine

– location confidential 4TRSA 150 <0.04

Mill # 2 (08/26/09) Location #1

– Wet End Paper Machine

– Upper Platform Fourdrinier 0 826 09

- 1 240 0.0 67 Ammonium

Bromide

Location #2

– Basement Machine Room

– Platform Adjacent to Open Mix Chest 0 8260 9

- 2 240 0. 13

Location #3

– Walkway Wet Machine Room

– Adjacent to Lab 0 826 09

- 3 240 <0.02

*Brea k through occurred and the actual result could be greater than indicated

. In addition, it is not known if these

results reflect NCl 3 or other chlorine species because a silica gel tube was not used.

The sampling method used by Galson Laboratories is based on the method developed by Hery, 1995 for use in evaluating NCl 3 exposures in swimming pools. This method was subsequently modifie d in Hery, 1998 for use in food processing plants to include a sulfamic acid treated silica gel tube in front of the treated filters. This tube was added to capture other chlorine species such as hypochlorites, monochloramine and dichloramine which would make the method more specific for nitrogen trichloride (i.e. trichloramine). Since this tube was not used in the samples submitted by Nalco, the results are not specific for nitrogen trichloride and could instead reflect the presence of other chlorine sp ecies such as monochloramine.

Conclusion

The registration of ammonium sulfate as Nalco 60620 is not anticipated to result in any risks of occupational exposure to ammonium sulfate because ammonium sulfate is of low toxicity and it is handled in a closed system. It is also anticipated that the re action of ammonium sulfate with sodium hypochlorite will be controlled to enhance the production of monochloramine while minimizing the production of trichloramine. It is recommended that the conditions needed to prevent the production of trichloramine be stated on the label.

The samples submitted by Nalco indicate that chloramines, which could include nitrogen

trichloride

, were detected at air concentrations ranging from 0.067 mg/m 3 to greater than >0.14 mg/m 3

. T he exact air concentration could not be determined , however, because breakt h rough

occurred . T he identity of these chloramines is also unknown because the sampling method did not include a silica gel tube which would have screened out the less volatile amines such as

monochloramine and dichloram ine

.Page 5 of 5 Human Studies Considerations

T he exposure stud ies included in this risk assessment (Hery et al., 1995 , Hery et al., 1998 )

ha ve been cleared for use in risk assessment by the OPP ethics reviewers.

References:

Kovacic et al., 1970. Chemistry of N

- Bromoamines and N

- Chloroamines, Kovacic, P., Lowery,
M., Field, K., Chemical Reviews, Volume 70, Number 6, pp 639

- 665, 1970

Hery et al., 1995. Exposure to Chloramines in the Atmosphere of Indoor Swimming Pools, Annals of Occupational Hygien e, Volume 39, Number 4, pp 427

- 439, 1995.

Hery et al., 199 8 . Exposure to Chloramines in a Green Salad Processing Plant , Annals of Occupational Hygiene, Volume 42 , Number 7 , pp 4 3 7

- 4 51 , 199 8

.

Mann, 2001b. Response to your email of May 11, 2011. Letter from Julie Mann of Steptoe and Johnson to Tracy Lantz of the Antimicrobials Division. May 13, 2011.