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Quality Control and Soil Quality Data in support of Baseline Environmental Monitoring at the Ammonium Perchlorate Rocket Motor Destruction (ARMD) Facility at the Letterkenny Army Depot, Chambersburg, Pennsylvania, 2016

From September to December, 2016, herein referred to as the baseline characterization period, monthly samples were collected from four groundwater wells, one surface-water site, and nine soil samples near the ARMD Facility. The only surface-water site sampled monthly during the baseline characterization period was upgradient of the facility. There was no streamflow at surface-water sites downgradient from the facility during the baseline characterization period on days when surface-water samples were collected. This Data Release presents the quality control data from ALS laboratories for the groundwater, surface-water, and soil samples (ALS_QAQC.txt). Quality control replicate and blank water samples that are stored in the USGS water-quality database are presented (ARMD_QAQC.txt). Three volatile organic compounds (VOCs), bromomethane, acetone, and chloromethane, and total chloride were detected in blank water samples. No constituents in groundwater or surface-water samples exceeded any U.S. Environmental Protection Agency (EPA) Maximum Contaminant Level (MCL). Dissolved iron (Fe) was the only groundwater constituent that exceeded a Secondary Maximum Contaminant Level (SMCL) established by the EPA. The SMCL for Fe is 300 micrograms per liter (µg/L), and samples from 3 of 4 wells exceeded this value, with exceedance values ranging from 1,100 to 2,600 µg/L. The only VOCs detected in groundwater samples were bromomethane, acetone, and chloromethane. All VOC detections in groundwater samples were less than the Report Detection Levels (RDLs). Detections of bromomethane, acetone, and chloromethane in groundwater ranged from 0.41 - 0.67, 3.4 - 5.4, and 0.44 - 0.46 µg/L, respectively. Bromomethane, acetone, and chloromethane were also detected in blank samples with values ranging from 0.40 to 0.65 µg/L, 5.2 to 5.8 µg/L, and 0.43 to 0.55 µg/L, respectively. No EPA established MCLs or SMCLs were exceeded for any constituents in samples collected from the surface-water site. Similar to groundwater results, some VOCs were detected in surface water at less than the RDLs. The VOCs detected in surface water were generally the same VOCs detected at less than the RDLs for groundwater. Perchlorate was detected in each surface-water sample collected at SW-U, with a mean concentration of 0.07 µg/L. All perchlorate results were less than the RDL of 0.2 µg/L. In addition, the soils data collected at the nine soil sampling sites is presented (ARMD_soils.txt). During the baseline characterization period, monthly soil samples were collected from 9 sites near the ARMD Facility. Soil sites SO-5 and SO-6 were not sampled in December 2016 since the area was paved over with asphalt. The soil samples collected during the baseline characterization period did not show any concentrations that exceeded any medium-specific concentrations (MSC) or soil screening levels (SSL) established by either the state of Pennsylvania or the USEPA. The state of Pennsylvania calculates MSCs based on either a function of acceptable concentrations in groundwater or based on health concerns if the soil is directly contacted. The USEPA derives acceptable concentrations of constituents (SSLs) in soil based on standardized equations combining exposure information assumptions with EPA toxicity data. The USEPA calculates SSLs for residential and industrial sites. Soil sites at the ARMD Facility were considered “industrial” for comparative purposes. There was at least one order of magnitude difference between any inorganic soil concentration detected and the MSC and/or SSL for that constituent. Four VOCs were detected in soil samples collected during the baseline period. None of the VOCs detected in the soils were within three orders of magnitude of any MSCs or SSLs established. The VOCs detected in soil were dichloromethane, methyl tert-butyl ether (MTBE), tetrachloroethene, and acetone (only detected once). Dichloromethane was the only VOC detected above the RDLs, with all samples