Document jB4Jqpkdj4jnZzaBOGoBDn4Lk

INTEROFFICE MEMORANDUM Date: From: Dept: Tel No: 15-Apr-1998 09:29am DAVID E. ELLIS ELLISDE AT Al AT CSOC Engineering (302) 892-7445 TO: Gregory A Chapman ( CHAFMAGA AT A1 AT WWPS ) CC: PHILIP A. PALMER CC: ANDREW S. HARTTEN CC: Roger J. Zipfel CC: ROBERT F. PINCHOT ( PALMERPA AT A1 AT CSOC ) ( HARTTEAS AT A1 AT CSOC ) ( ZIPFEL AT Al AT WWPS ) ( PINCHORF AT A1 AT WWPS ) Subject: RE: C-8 PACE Team Meeting Greg: Andrew found analyses of the organic carbon concentration in aquifer materials under the anaerobic treatment units. After reviewing the data we believe that 0.2% is the most appropriate carbon concentration to use. 0.2% carbon is high for an aquifer. The high carbon content dominates the calculation of apparent loss rate. We now estimate a half life of 47.5 years for apparent C-8 loss in the aquifer. A key assumption made in our interpretation method is that transport and biodegradation are at a steady state. When we see a 47.5 year half life, it isn't clear that we are dealing with a steady state. This long a half life could represent either C-8 degradation or simply show the effect of the high adsorption of C-8 in the aquifer. Is the meeting still 1 p.m. on May 7th? Regards, , & 30 Dave vo "5:TMr rC's' O C3 VCOO o r & Woo EID918181 C00204