Indoor Air Quality Testing at the Middle River Complex

Transcription

1 Indoor Air Quality Testing at the Middle River Complex September 2016 Lockheed Martin has been investigating, and more recently, cleaning up contaminants in soil and groundwater at the Middle River Complex. These contaminants are likely the byproduct of historical operations at the Complex. Site contaminants remaining in groundwater and soil include volatile organic compounds (VOCs), which have the potential to move from underground into buildings through cracks in foundations and basement floors, sumps and utility openings by a process known as vapor intrusion. Do employees need to be concerned? No, available information indicates that employees do not need to be concerned about air quality resulting from historical environmental impacts. There is a vapor intrusion prevention program in place to make sure indoor air is safe. The program includes two basic components discussed below: an indoor air and vapor testing program, and a subslab depressurization system that collects and treats VOC vapors located under the building. Employees are always encouraged to ask questions and bring up concerns and issues so that they may be promptly addressed. What indoor air and soil vapor testing has Lockheed Martin done to date? Since 2006, Lockheed Martin has conducted 21 rounds of air quality testing inside A, B and C Buildings, and has tested the vapor in soil directly beneath these buildings, to ensure that indoor air quality at the Middle River Complex is safe for workers. Sampling is conducted generally twice a year to account for differences in conditions between summer and winter, when heating, ventilation and air conditioning can affect the rate at which soil vapors may be pulled into, be blocked from entering, or pushed out of a building. In addition, outside air is monitored at locations surrounding the Middle River Complex to measure chemicals that might already be present in outside air from other sources. These data help identify whether chemicals found inside the facilities are from site operations, outside sources, or from underneath the buildings. The Round 20 air quality testing was conducted during the second week of February. Based on results, Lockheed Martin conducted an additional investigation in A Building basement. The Round 21 testing was conducted in August. What mitigation measures has Lockheed Martin already taken? A sub-slab depressurization system (SSDS) was installed beneath the former Plating Shop in A Building in 2008 as a proactive measure to minimize the potential for vapor intrusion. The SSDS draws vapor from the soil beneath the foundation slab, treats it and releases it into the outdoor air. In addition to the periodic monitoring described above, the vapor is tested monthly to assess the performance of the SSDS. Lockheed Martin recently expanded the SSDS by installing new pipes and increasing the power of the blower to capture and treat sub-slab vapor. In November 201, five holes were drilled in the floor in the east-central portion of A Building and PVC pipes were installed in each of the holes. In March and April 2016, these pipes were connected to another pipe overhead and the new higher-capacity blower was installed on the A Building loading dock. This highercapacity blower draws potentially contaminated vapor from elsewhere beneath A Building. The blower connects to the treatment system, which releases cleaned air outside. For More Information Tom Blackman, Project Lead, (01) 8-220, Cell (20) , Tom.D.Blackman@lmco.com Mékell Mikell, Communications Representative, (01) 87-6, Mekell.T.Mikell@lmco.com

2 2 In the southern part of the A Building basement (at and around sampling location 0-A, see figure attached), trichloroethene (TCE), a cleaning solvent, has occasionally been found in indoor air samples at concentrations greater than its conservative (meaning low) health-risk-based screening level of 8.8 micrograms per cubic meter. This screening level was established by the U.S. Environmental Protection Agency (EPA) and its Maryland counterpart, the Maryland Department of the Environment (MDE). Because of these exceedances, air filtration units were installed in the basement in January 201 and have been operating continuously. Until the recent round of sampling, air quality has been better than EPA and MDE requirements, which indicates that the air filtration units are effective. However, at location 18-A in the A Building basement, trichloroethene (TCE) was detected in indoor air at a concentration of 12 micrograms per cubic meter. This sampling location is near location 0-A, where exceedances have been found previously even when air filtering units have been operating continuously. Although the trichloroethene concentration was less than the healthrisk-based screening level when indoor air from this location was resampled, additional investigation is needed to find an effective long-term solution for the intermittent issues with A Building basement air quality. What was found during A Building basement sampling conducted in April and May 2016? Because of the exceedances that have been identified in A Building basement, Lockheed Martin met with EMCOR, the on-site maintenance contractor, to obtain additional information about the basement underground network. Many of the sumps and drains in A Building basement were historically used to manage groundwater infiltration. The purpose of the April and May sampling of A Building basement was to provide additional information on why trichloroethene (TCE) is sometimes detected in the indoor air. Indoor air samples collected using a field portable instrument from locations directly above floor features (at ground level) had concentrations greater than the screening level. However, only one indoor air sample, collected from about five feet above the floor to evaluate the breathing zone, was greater than the screening level. This elevated level was from a location near the floor grate where there were previous exceedances. Trichloroethene was also detected in indoor air samples using the conventional sampling method and an exceedance of the screening level occurred above one of the sump pits. It is our understanding that no one is working in the basement for extended periods of time, and the higher levels of TCE have been occasional and limited to the one area of the basement with sumps and drains. What was found during sampling conducted in August 2016? In August, all indoor air sampling results were below U.S. Environmental Protection Agency (EPA) and Maryland Department of the Environment (MDE) riskbased screening levels. Trichloroethene was infrequently detected in A Building and C Building indoor air and at concentrations less than its health risk-based screening level of 8.8 micrograms per cubic meter. The greatest concentrations of trichloroethene were detected in samples collected from A Building basement at locations 0-A and 18-A, where the air filtration units have been operating continuously. These locations are where exceedances of screening level previously occurred. The concentration of TCE at location 0-A was 6 micrograms per cubic meter and the concentration at 18-A was 2.7 micrograms per cubic meter. What comes next? While worker occupancy in A Building basement is intermittent, Lockheed Martin will continue to operate the air filtration units and continue to monitor TCE concentrations in the A Building basement to ensure protection of human health. Lockheed Martin is committed to identifying all exceedances of health-risk-based screening levels by historical environmental sources in indoor air. It is now Lockheed Martin s standard procedure to collect a followup sample at any location where higher levels of the indoor air screening level of TCE are detected. This will help determine if the exceedance is infrequent or more routine. Lockheed Martin will continue to monitor this area and consider additional steps, including more sampling to identify the source of the vapor and the possibility of sealing the floor drain or installing ventilation fans. Who do I contact if I have questions? Tom Blackman, Project Lead, (01) 8-220, Cell (20) , Tom.D.Blackman@lmco.com Mékell Mikell, Communications Representative, (01) 87-6, Mekell.T.Mikell@lmco.com

3 A G D C B F A GA GB GC GD GE GF GG GH GJ GK GL GM H J K L M P Q R S T U V W ELE VAT OR X 2 1 1/2 O N 1/2 1 2 AIR-0-A. AIR-07-A A SV-01-A-20: 0 J µg/m IA-18-A-20: 12 µg/m AIR-116-A. AIR-18-A 100 AIR-0-A AIR-076-A AIR-078-A 11 SV-118-A-20: 200 µg/m AIR-1-A 2 SV-07-A-20: 00 µg/m SV-16-A-20: 7000 µg/m, 000 µg/m (resample) AIR-101-B 6 AIR-100-B AIR-12-C 7. AIR-1-C. AIR-11-C 10 AIR-088-C 6 AIR-00-C SV-001-C-20: 0 µg/m AIR-10-C 1. SV-126-C-20: 0 µg/m SV-102-C-20: 100 µg/m E AIR-081-A 0.6 AIR-1-C AIR-060-C 220 AIR-1-C 0.6 AIR-12-C AIR-11-C F Map Document: (P:\GIS\Middle_River\MapDocs\MXD\bldg_abc_tce_tags_rnd20_1117_poster.mxd) 0/1/16 -- JEE FIGURE 1 TRICHLOROETHENE SAMPLE RESULTS ROUND 20 BUILDINGS A, B AND C LEGEND #* IAQ, 1st Floor #* IAQ, Basement SV SSD Treatment Unit Soil Vapor Sample Results, in µg/m < > IA = Indoor Air Sample The current MDE indoor air screening level for TCE is 8.8 µg/m. The concentration circle sizes are approximate ug/m 2 ug/m Feet 0/1/16 JEE

4 1/ A E F D C G GA GB B ELEVATOR PGH P:\GIS\MIDDLE_RIVER\MAPDOCS\MXD\BLDG_A_TAGS_RND20_IA_SSV_POSTER.MXD 0/1/16 JEE F A FIGURE -1 ROUND 20 TCE INDOOR AIR AND SUB-SLAB VAPOR SAMPLING RESULTS BUILDING A AIR-0-A. AIR-07-A 2.7 Legend Soil Vapor Sample Results < 2 µg/m µg/m µg/m > µg/m Building A Basement AIR-076-A SV-16-A-20: 7000 µg/m, 000 µg/m (resample) Excavation Area SSD Treatment Unit IA = Indoor Air Sample TCE - Trichloroethene The current MDE indoor air screening level for TCE is 8.8 µg/m. The concentration circle sizes are approximate. AIR-078-A 11 AIR-116-A ug/m 2 ug/m SV-01-A-20: 0 J µg/m SV-118-A-20: 200 µg/m IA-18-A-20: 12 µg/m AIR-18-A 100 SV-07-A-20: 00 µg/m AIR-1-A 2 AIR-0-A 0 6 Feet AIR-081-A 0.6 0/1/16 JEE

5 GK GL GM H J K L M O N P Q R S T U V W X PGH P:\GIS\MIDDLE_RIVER\MAPDOCS\MXD\BLDG_C_TAGS_RND20_IA_SSV_POSTER.MXD 0/1/16 JEE FIGURE /2 ROUND 20 TCE INDOOR AIR AND SUB-SLAB VAPOR SAMPLING RESULTS BUILDING C SV-126-C-20: 0 µg/m AIR-1-C AIR-10-C 1. Legend Soil Vapor Sample Results < 2 µg/m µg/m µg/m > µg/m Tunnel TCE - Trichloroethene The current MDE indoor air screening level for TCE is 8.8 μg/m. The concentration circle sizes are approximate. AIR-1-C. AIR-060-C 220 AIR-12-C 1000 ug/m 2 ug/m AIR-1-C 0.6 AIR-11-C 10 AIR-102-C 100 SV-102-C-20: 100 µg/m A AIR-12-C 7. AIR-088-C 6 AIR-11-C AIR-00-C SV-001-C-20: 0 µg/m 0 6 Feet 0/1/16 JEE