U.S. Environmental Protection Agency, 26 W. Martin Luther King Dr., Cincinnati, OH 45268

A -- MODIFICATION TO PURCHASE ORDER # 8C-R017-NALX, SOL 8C-R017-NALX DUE 050598 POC Hans Schellhas E-MAIL: U.S. EPA -- Cincinnati Contracts Management Division, schellhas.hans@epamail.epa.gov. The U.S. EPA intends to negotiate on a sole source basis with Dr. Larry Hansen in order to modify Purchase Order No. 8C-R017-NALX. NCEA-Cincinnati has a need for an additional task under this existing Purchase Order pertaining to the risk assessment of PCB mixtures in breast milk of mothers. The objective of this task is to develop Toxicity Ranking in risk assessment of ortho-substituted non-dioxin-like PCBs based on enzymatic, endocrine and neurotoxicity data. In addition, determine the multimedia multi pathway exposure of infants to ortho-substituted non-dioxin-like PCBs. THIS IS NOT A REQUEST FOR PROPOSALS. Sources who wish to be considered should submit documentation to the office identified above, which esteblishes the capabilites to perform the work identified above, and the unique relationship and knowledge with the current research and data which Dr. Hansen has under this existing Purchase Order. Documentation may be submitted to Hans Schellhas and the subject facsimile number is (513) 487-2107. This must be submitted within fifteen (15) days of this announcement. (0110)

Loren Data Corp. http://www.ld.com (SYN# 0003 19980422\A-0003.SOL)