Results of the second quarter calendar year 2003 (2Q2003) RFCA Groundwater Report are discussed here.

Groundwater analytical data were evaluated using groundwater action level criteria as described in RFCA Attachment 5 and in the FY2003 Integrated Monitoring Plan (IMP).

Groundwater Monitoring Program personnel at RFETS attempted to collect water quality samples from 344 wells, building drains, and sumps during 2Q2003. This work was performed as prescribed in the IMP. Additional wells are included that were sampled as part of the Snapshot Sampling Project (K-H, 2003). During the quarter, 116 wells or drains were dry, or contained insufficient water for collection of all requested groundwater samples. Most dry locations were visited several times in attempts to collect the required water samples. However, 91 locations remained completely dry during the quarter. A total of 253 sampling locations produced sufficient groundwater for collection of either the full requested sample suite, or a partial sample suite.

Groundwater Analyte Concentrations Greater Than Tier I

Table 3-5 lists data for 36 “Tier I events” in which 2Q2003 groundwater analyte concentrations (or activities) were found to be greater than the corresponding Tier I action levels. Groundwater collected from 25 wells contained one or more of the Tier I events. Thirteen of the events are associated with Performance Monitoring wells, 11 events with non-IMP wells, 5 with Plume Degradation wells, 3 with Plume Extent wells, 2 with Plume Definition, and 2 with D&D wells. Note that 35 of the 36 Tier I events pertain to known chlorinated solvent plumes in RFETS groundwater. The remaining event is for U-238 in groundwater from Performance Monitoring well 70099. Chlorinated volatile organic compounds (VOCs) with the greatest number of Tier I events include: carbon tetrachloride (18 events), TCE (10 events), and PCE (6 events). The highest carbon tetrachloride concentration measured in groundwater during 2Q2003 was 44000 ug/L in Well 18499 located in the carbon tetrachloride plume at IHSS 118.1.

Recently installed Plume Definition Well 33502 is located south of Building 371 and contains groundwater with above Tier I concentrations of vinyl chloride (reaching 1200 ug/L during 2/18/03 water sampling, 1Q2003). During 2Q2003 sampling, the well water contained a vinyl chloride concentration of 991 ug/L.

Tier I Reportable Results

During 2Q2003, five reportable Tier I groundwater events were identified. These reportable events are tabulated in Table 3-6, and they occurred in water sampled from two Plume Definition wells (33502 and 18399), and Plume Extent Well 21002. Well 33502 has Tier I reportable vinyl chloride, as discussed above. Well 18399 is located in IHSS 118.1, and Well 21002 is located west of Building 771.