Environmental Decision Memo
for Food Contact Notification No. 000142

Date: June 27, 2001

From: Environmental Scientist, Environmental Group
Division of Chemistry Research and Environmental Review

Subject: FCN No. 142 - Silicon based defoaming agent used in the manufacture of paper/paperboard

Notifier: Dow Corning Corporation
Midland, MI 48686-0994

To: Division of Food Contact Notification
Attention: Vivian Gilliam
Through: Supervisor, Environmental Group

Attached is the Finding of No Significant Impact (FONSI) for this premarket notification. When this notification becomes effective, this FONSI and the notifier's April 30, 2001, Environmental Assessment (EA) and our Supplement to the EA may be made available to the public. Please let us know if there is any change in the identity or use of the food-contact substance that would be inconsistent with the identity and use described in the FONSI.

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Finding of No Significant Impact

A food contact notification (FCN No. 142), submitted by Dow Corning Corporation, to provide for the use of a silicon based defoaming agent in the manufacture of paper and paperboard.

The Environmental Group has determined that allowing this notification to become effective will not significantly affect the quality of the human environment and therefore will not require the preparation of an environmental impact statement. This finding is based on information submitted by the notifier in an environmental assessment (EA) and our supplement to that EA dated April 30, 2001.

Prepared by__________________________________________ Date: June 27, 2001
Jonathan L. Chappell, Environmental Scientist
Environmental Group
Division of Chemistry Research and Environmental Review
Office of Food Additive Safety
Center for Food Safety and Applied Nutrition
Food and Drug Administration

Approved by__________________________________________ Date: June 27, 2001
Layla Batarseh, Group Leader
Environmental Group
Division of Chemistry Research and Environmental Review
Office of Food Additive Safety
Center for Food Safety and Applied Nutrition
Food and Drug Administration

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Supplement to the Environmental Information
for Food Contact Notification No. 142

This document incorporates by reference the notifier's environmental assessment (EA) dated April 30, 2001.

In the environmental assessment (EA) for this notification, the notifier refers to Volume 3, Organosilicon Materials, of the Handbook of Environmental Chemistry Materials. The food contact substance that is the subject of FCN 142 is a member of this class of chemicals. More specifically, in Format Item 8 of the EA, the notifier stated that the subject of this notification is a polyethermethylsiloxane (PEMS) that is very similar to the PEMS 3 fiber finish product discussed in Chapter 8 of the Handbook, Vol. 3. In order to complete this environmental record, information from the referenced book, as well as information from the EA, is summarized in this supplement.

Introduction of Substances Into the Environment

The notifier did not estimate the expected introduction concentration (EIC) of the substance into the environment. The notifier provided a market volume based on 5th year production estimates and then claimed that 97% of the subject substance will bind to sludge during wastewater treatment. This claim is based on the physical and chemical properties of polydimethylsiloxane (PDMS), a chemical closely related to PEMS. However, the text to which the notifier referred states that, "...the solubility of commercial PEMS can range from insoluble to the parts per hundred range...." But "...one laboratory study [M Ziemelis (1996) Dow Corning Corp (unpublished data)] suggests that commercial PEMS materials readily adsorb to sludge, similar to PDMS." Since the solubility of the subject substance is not included with the notification and the referenced laboratory study is unpublished, it is unclear whether the subject substance will totally adsorb to biosolids during wastewater treatment. Therefore, we calculated a conservative concentration of the subject substance in wastewater based on the following information:

1) Additives are typically introduced into the papermaking process at the headbox. According to the notifier, slurry in the headbox contains about 0.5% by wt pulp. This translates to about 5 x 10^-3 kg of fiber per kilogram slurry.

2) The notifier states that about 45% of the subject substance that is added to the process remains with the paper. Conversely, about 55% of the subject substance remains in the process water and is removed with the effluent.

3) The notifier states that the subject substance will be present in the dry fiber at a concentration of 0.009% based on dry weight. Specifically, there are 90 mg of the subject substance in 1 kilogram of dry fiber.

Using the above assumptions, we calculated a concentration for PEMS in waste effluents as follows:

(90 mg PEMS/kg fiber) x (5 x 10^-3 kg fiber/ kg slurry) = 0.45 mg PEMS/ kg slurry = 0.45 ppm

0.45 ppm x 0.55 = 0.25 ppm in the removed process water.

This is a conservative estimate of the expected introduction concentration (EIC) of PEMS in the wastewater effluents of paper mills. However, we expect the concentration to be much lower due to dilution with other waste waters from the paper mill and any possible adsorption to biosolids during wastewater treatment.

Fate of Substances Released in the Environment

Paper mills discharge effluents to the environment either directly or indirectly through publicly owned treatment works. We estimated the expected environmental concentration (EEC) of PEMS in receiving streams based on our estimated EIC of 0.25 ppm and on information from EPA on mean and low stream flow rates from indirectly and directly discharging pulp, paper, and paperboard mills.

The highest EEC for a directly discharging paper mill is 0.21 ppm. However, a concentration this high is unlikely because it is for conditions of low flow for a small percentage of paper mills (5th percentile). In fact, this estimate basically assumes that the receiving stream will only slightly dilute the concentration of PEMS, which is an unlikely scenario. We predict that the concentration of PEMS in receiving waters will be much lower than 0.21 ppm.

Environmental Effects of Released Substances

A comparison of the most conservative EEC of 0.21 ppm in the aquatic environment to the toxicity data in Table 1 shows that there is little concern regarding aquatic toxicity of this chemical. The EEC of 0.21 ppm falls several orders of magnitude below the lowest measured toxic concentration of 115 ppm for rainbow trout.

Table 1: Toxicity of "PEMS 3 fiber finish" to various aquatic organisms

Conclusion

Based on evidence that this substance has a low toxicity and on low expected environmental concentrations, we do not anticipate a significant environmental impact from the use and disposal of the subject substance.