ARCHIVED REPORTS XR0000886 - Laserfiche WebLink

Home Browse Search

Plan was the installation of three CPTs.To date CPT#1,CPT#2 and CPT#3 have been installed. Soil and groundwater samples extracted during the installation of CPTs indicate gasoline contamination to a depth of eighty-five feet(see a recap attached). On May 2 and 3, 2000 the soil borings for both MW#5 and MW#b were made as described in the work plan of 311712000. Monitoring wells were installed in both of these soil bores. The work plan of 3/17/2000 also included a soil bore and monitoring well (MW#4)to be installed in the sidewalk on the north side of Lafayette Street. This soil bore was not completed as planned. An unknown underground storage tank was encountered in the direct path of the soil bore. As a result of this encounter, the soil bore was abandoned and the local agencies were notified. CPT#3 was installed on June 13,2000 in the Caltrans right of way. This CPT is northeast of the site, and the data gathered is in the report issued for that work. All monitoring wells have been sampled quarterly, and a recap of the findings is attached. A work plan to expand the horizontal definition of the contamination plume was approved in December of 2000. This work plan called for the installation of three new CPT's within the Caltrans R/W to the north of the project site. These CPT's were completed on March 8, 2001 and soil and water samples were extracted to a depth of 125 feet. Also, included in the work plan of December 2000 was the installation and testing of four new monitoring wells,(MW-8S,MW-8D,MW-7,MW- 9) to be placed on the project site or the adjacent property. These monitoring wells were completed on April 11, 2001. C� In January of 2002 the owners of this property removed the apartment house structure on the east side of the property. At the time of this report that portion of the property is clear without any structures or other improvements. In April of 2002 the author submitted a work plan for the installation of an extraction well with pump test to determine the viability of a pump and treat remediation system. On August 9 & 10, 2002 the extraction well installed for the pump test was completed and developed. REPORT OF FINDINGS FOR THE THIRD QUARTER 2002 MONITORING EVENT Procedure On September 17,2002,Del Tech Geotechnical Support Services extracted water samples from all of the monitoring wells on the above stated property. The work was supervised by Foothill Engineering. Some of the monitoring wells were in need of maintenance with missing locks and low grout column. All samples were extracted using the tube with check valve pump system.Purge rates were+/-.5 g.p.m. and the physical properties of the groundwater can be found in the Del-Tech Field Report which is attached and part of this report. The replacement and original monitoring wells were sampled for analysis. The original monitoring wells (MW-1, MW-2, MW-3) were used to establish the groundwater elevation and hydraulic gradient. All samples were transported under chain of custody to Sherwood Labs of Hilmar, California for analysis by EPA method SW8020F. All water sample analysis and groundwater elevations are summarized in the attached tabular recap sheet(see attached recap sheets). Copies of the original Laboratory data sheets from this sampling event are also attached and are a part of 2