UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

OFFICE OF PREVENTION, PESTICIDES

AND TOXIC SUBSTANCES

MEMORANDUM

DATE:		November 27, 2007

SUBJECT:		Organic Esters of Phosphoric Acid:  Environmental Fate
Disciplinary Chapter for the Issuance of the Reregistration Eligibility
Decision (RED) Document  

			Case No.:  4122

			PC Code: 111286, 129079, 129080

			DP Barcode: D347009

FROM:		James Breithaupt, Agronomist

 		Risk Assessment and Science Support Branch (RASSB)

	 		Antimicrobials Division (7510P)

              

TO:			Heather Garvie, Chemical Review Manager 

Diane Isbell, Team Leader

Mark Hartman, Chief

			Regulatory Management Branch II

			Antimicrobials Division (7510P)     

        

THROUGH:		Richard C. Petrie, Team Leader

			Team Three

And

Norm Cook, Chief

	 		Risk Assessment and Science Support Branch

	 		Antimicrobials Division

REGISTRANT:	Interface Research Corporation

Attached is the Environmental Fate Disciplinary Chapter for Phosphoric
Acid Esters for the purpose of issuing a Reregistration Eligibility
Decision (RED). 

Conclusions

The Agency considers registered uses of organic esters of phosphoric
acid to result in limited environmental exposure.  If a spill of these
organic esters acid were to occur in the environment, it is likely that
terrestrial and aquatic organisms would be exposed to a mixture of
organic esters of phosphoric acid, phosphoric acid itself, and salts of
phosphoric acid (e.g., calcium phosphate).   Salts of phosphoric acid
are generally low in water solubility and would precipitate in the
presence of water.

Mineral acids (e.g. phosphoric acid) pose a potential hazard to the
aquatic environment not because of inherent toxicity but instead due to
their ability to change the pH of receiving waters and create
eutrophication.  The pH is an important factor in the chemical and
biological systems of natural waters, and the extent of pH change will
depend on the buffering capacity of the water:sediment system, the
quantity of the spill, and the characteristics of the receiving water
body (e.g. size, depth, flushing).  In addition, eutrophication from
sudden additions of plant nutrients such as phosphorus can result in
rapid algal and aquatic plant growth in water bodies and cause oxygen
shortages which
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