Document 6BQ1gGdaLj8Y5qbRbvyNDM4Y3

AR226-2634 CM CM nTnxoatl AR226-2634 JANUARY 2003 BASELINE C-8 SAMPLING DUPONT FAYETTEVILLE WORKS FAYETTEVILLE, NORTH CAROLINA Date: March 2003 Project No.: 18983753.00037 CORPORATE REMEDIATION GROUP An Alliance between DuPont and URS Diamond Barley Mill Plaza, Building 27 Wilmington, Delaware 19805 January 2003 Baseline C-8 Sampling Introduction During the week of January 27th 2003, groundwater was sampled from four monitoring wells at the DuPont Fayetteville Works. In addition, a combined surface and wastewater sample was collected above Outfall-002. These samples were collected in order to establish baseline conditions at the facility during the initial activation of APFO (C-8) production. C-8 Sampling Prior to initiating sampling activities, well locations were field identified and sampling locations were selected based on site coverage and accessibility. Figure 1 (attached) shows the locations of the four wells selected for sampling. Before sampling activities began, depth to water and depth to bottom were measured for each well to the nearest one hundredth of a foot. Prior to sampling, monitoring wells were purged using low-flow sampling methods where possible. The low-flow bladder pump was gently lowered to approximately the middle o f the screened interval in the well and the well was purged. During low-flow purging, pH, specific conductance, dissolved oxygen, oxidation-reduction potential and temperature were monitored approximately every three minutes using a flow-through monitoring cell. Purging was considered complete when all field parameters stabilized (variations in values were within 10 percent of each other for three consecutive readings three minutes apart). Once field parameters stabilized, groundwater was sampled directly from the end o f the discharge tubing. Wells SMW01, NAF-01 and MW-IS were sampled using this low-flow sampling method. Alternatively, if low-flow purging was not practical due to field conditions (i. e. too little water in the well), monitoring wells were evacuated using a disposable bailer. Well evacuation stopped when at least three volumes were evacuated and three consecutive readings of pH and specific conductance were stabilized to within ten percent. After evacuation and parameter stabilization, the groundwater was sampled directly from a disposable bailer. Well SMW-02 was sampled using this method. The combined surface and wastewater sample was collected approximately ten feet upstream from Outfall-002, after the confluence of all plant discharges. The location of Outfall-002 is shown on Figure 1 (attached). The water sample was collected by submerging the sample bottle into the water and then filling the bottle. All equipment used for sampling activities was pre-cleaned or was dedicated as per the Groundwater Investigation Quality Assurance Project Plan For Washington Works Plant (QAPP), dated January 2002. All samples were collected and handled in a manner described in die QAPP, including the sample collected above Outfall-002. Fayetteville Scope.doc Mar. 6. 03 Wilmington, DE 1 January 2003 Baseline C-8 Sampling C-8 Results The C-8 results for the four wells and Outfall-002 are presented in Table 1 (attached). This table provides the sample name and date o f the sample, the depth to water and depth to bottom for each well, the measured C-8 result in ug/1, and comments, if applicable. The groundwater from well NAF-01 is the only sample that had a detectable concentration of C-8. The concentration measured in this well was 0.0649 ug/1. Samples from the other wells and the outfall had C-8 concentrations that were either below the practical quantification limit of 0.05 ug/1 (NQ) or non detectable (less than 0.01 ug/1; ND). Fayetteville Scope.doc Mar. 6, 03 Wilmington, DE 2 i Table 1 January 2003 - Baseline C-8 Sampling DuPont Fayetteville Works Fayetteville, North Carolina Sample Name SMW-01 Depth to Depth to Datei : Water (ft ) Bottom ( ft} 1/27/2003 13.55 22.84 SMW-02 NAF-01 MW-1S MW-1S-2 1/27/2003 1/27/2003 1/28/2003 1/28/2003 14.79 7.14 18.81 18.81 17.12 18.31 32.25 32.25 Outfall-002 1/28/2003 C-8(ug/L) Comments ND(<0.01) shallow well Installed 1/21/03 for C-8 sampling shallow well installed 1/21/03 for C-8 sampling, well bailed due to ND(<0.01) low water level 0.0649 NQ(<0.05) NQ(<0.05) water is very Toaniyj sSinpie t/Uiiet/ieu upsuwdiii ui uuucm sonijjiniy NQ(<0.05) point but after confluence of all plant discharges 3/6/2003 Page 1 fayetteviile.xls