ARCHIVED REPORTS XR0010952 - Laserfiche WebLink

Home Browse Search

i h4 c7alogicat Tecknks Inc. Page 4 i COE-:Former Arco Site Monitoring Report-VETS Project No.: 750.2 L ` January. 21,2003 As stated above, the VETS has removed approximately 675 gallons of gasoline from the site. The spike test performed from December 10, 2002 until January 1, 2003 shows that significant contamination is not present at the site. The influent concentration on December 10, prior to shutting the system down, was 1.5 mg/L while the concentration of the influent one-hour after I restart, January 1, 2003 was 1.3 mg/L. The concentration of the sample collected the following day was 1.9 mg/L. This shows that significant volumes of contamination are not still present in the soil of the .site. The concentrations fluctuate slightly with airflow, temperature and j atmospheric pressure but there was not a significant increase in concentration after the three week."rest period". The laboratory data sheets for the January 1 & 2, 2003 sampling are included in Appendix B. The laboratory data sheet for the December 10, 2002 sampling was submitted previously as part of the monthly monitoring data. The concentrations of gasoline and BTEX in the groundwater at the site have decreased to the point'of only showing trace concentrations of Xylene in MW-1. Groundwater concentrations in MW-1 started decreasing in March, shortly after startup of the VETS. All other groundwater a monitoring wells at the site are non-detect. Groundwater analytical data is included in Table 2 ' of Appendix A. A groundwater monitoring- report for the latest round of groundwater 1 monitoring will be prepared shortly. li Measurements of ORP (Table 4) show that the wells of this site have a fairly high potential for oxidation/reduction reactions and that the site should have a fairly high DO concentration. { In their January 11, 2001, correspondence, SJC-PHS/EHD states that- "San Joaquin County has established that primary and secondary drinking standards, known as maximum contaminant levels, are appropriate cleanup goals, at a minimum,for all contaminated underground storage i tank sites within the county". The groundwater at the site is below these standards and it is {, defined both laterally and vertically. The Permit to Operate from the San Joaquin Valley Unified Air Pollution Control District was for a period of one year from startup. The system was started in February of 2002 and so the permit is due to expire. Rather then renewing the permit and continuing operation of the system at low removal rates, the site should be.considered for closure. I 3 , yy.•� I: I } n