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last soundings The hydraulic gradient of the water table has changed slightly The original direction Of flow gradient was South 75 degrees East, and on 10/I9/98 it was almost due East The 4/1/99 gradient is down slope North 80 degrees East with S-0 002 The 9/09/99 soundings show the down slope gradient to be North 79 degrees East with S=0 0016 Soundings for 12;21/99 indicate the down slope gradient was at North 83 degrees East with S=0 0023 For this event the soundings resulted in a gradient with a beanng of South 88 degrees East with S=0 002 (see attached site map) Pump rates for purging continue to be between 1 0 gpm and 2 0 gpm WATER SAMPLE ANALYSIS FINDINGS In general, monitoring well samples taken on 3/31/2000 were very similar to previous samples Analysis by EPA Test Method 8260A was not repeated,as the 4/l/99 samples were non-detect The MW-3S is the only monitoring well with BTEX compounds This is the same BTEX result as the last event The compound 1,2-Dichloroethane is still present in low concentrations in all wells with the exception of MW-4S and MW4D (see recap of data attached) CONCLUSIONS BETX compounds in the MW#3S remain near the same concentrations as the last sampling event This monitoring well is receiving the highest impact of all the wells due to TANK#1 (the Stoddard's Solvent tank), which is up gradient and Northwest of MW#3 S Chlorine compounds are present in low concentration in all but MW#4S In general, Halocarbon concentrations in all water samples are the same as the last sampling penod Only M W-3 S exceeds National Primary Drinking Water Regulation for 1,2- Dichlorethane at 5 8 ug/L The present 5 8 ug/L is considerably lower than 2$ ug/1 found in the sample extracted on 6/11/98 RECOMMENDATIONS The author requests that all monitoring wells be sampled in semi-annual events to conserve financial resources In response to your verbal request for the installation of a new monitoring well on the East side of California Street, this author will seek approval from Mrs Higgins, the owner of the property, to develop a work plan to install the new monitoring well as soon as she returns from vacation outside of the USA Please contact this office at 209/368-9381 if any questions arse from this report Respectfully submitted, QgE4FESSld RIFE- Foo E e CO No 1975 in _ OFC cc Mrs Helen Higgins, 3 1 C CIRCLE CAMERON PARK CA 95682 2