ARCHIVED REPORTS_XR0004887 - Laserfiche WebLink

Home Browse Search

• Quik Stop No 121 Additional On-Site and Offsite Soil and Groundwater Investigation Page 4 CPT Groundwater Sampling After the direct-push boring was extended to either the target depth or refusal at each CPT location, groundwater samples were collected using a push-in PVC Piezometer (PIPP), which is similar to a "Hydropunch" sampling device The PIPP sampling system consists of two principal components a steel, outer protective casing with a 2-inch outside diameter (O D ), and an inner 1-inch O D PVC slotted screen The PIPP was attached to a string of steel rods and advanced with the CPT rig to the desired sampling depth An expendable stainless steel tip was attached to the end of the outer casing to prevent soil or groundwater from entering the PIPP as it was being advanced into the ground After reaching the desired sampling depth,the steel protective casing was retracted and the PVC casing was exposed Groundwater samples were then collected, using a pre-cleaned, stainless steel bailer, which was lowered through the center of the steel rods and into the screen Upon retrieval of the bailer, the water samples were transferred to the appropriate laboratory-supplied bottles, labeled, logged on chain-of=custody forms and stored in a chilled chest containing water ice for preservation in the field and during transport to the analytical laboratory • Upon completion of the PIPP groundwater sampling at each CPT location, the holes were sealed with bentonite grout, in accordance with procedures approved by the representative of San Joaquin County Health Services Department Each CPT hole was grouted using a tremmie method, pouring grout though the open rod as it was retracted from the hole The upper 6 inches of each hole was sealed with cold, patch asphalt Site Monitoring Well Sampling On July 5, 2000, CCI sampled all three on-site wells Before groundwater sampling, CCI measured the depth to groundwater using an electronic sounding tape and field-checked the wells for the presence of free-floating product by collecting a sample in a clear acrylic bailer Free- floating product was not observed, however, a slight odor was noted in the water at monitoring well MW-3 Each well was purged of stagnant water prior to the collection of a sample Normal field measurements, including pH, conductivity, and water temperature, were periodically recorded during the purging process A sample was collected when these parameters stabilized to within 10% of each other At least three well casing volumes of groundwater were purged from each well before sampling Samples were (a) collected with a clean disposable bailer, (b) transferred to appropriate laboratory-supplied bottles, ( c) labeled, (d) logged on a chain-of-custody form, and (e) placed in a chilled ice chest for transportation to a state-certified laboratory Monitoring well purge data can be found in data Table 1