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Title: Hanford Site Groundwater Monitoring for Fiscal Year 2005

Abstract

This report is one of the major products and deliverables of the Groundwater Remediation and Closure Assessment Projects detailed work plan for FY 2006, and reflects the requirements of The Groundwater Performance Assessment Project Quality Assurance Plan (PNNL-15014). This report presents the results of groundwater and vadose zone monitoring and remediation for fiscal year 2005 on the U.S. Department of Energy's Hanford Site, Washington. The most extensive contaminant plumes in groundwater are tritium, iodine-129, and nitrate, which all had multiple sources and are very mobile in groundwater. The largest portions of these plumes are migrating from the central Hanford Site to the southeast, toward the Columbia River. Carbon tetrachloride and associated organic constituents form a relatively large plume beneath the west-central part of the Hanford Site. Hexavalent chromium is present in plumes beneath the reactor areas along the river and beneath the central part of the site. Strontium-90 exceeds standards beneath all but one of the reactor areas. Technetium-99 and uranium plumes exceeding standards are present in the 200 Areas. A uranium plume underlies the 300 Area. Minor contaminant plumes with concentrations greater than standards include carbon-14, cesium-137, cis-1,2-dichloroethene, cyanide, fluoride, plutonium, and trichloroethene. Monitoring for the Comprehensive Environmental Response,more » Compensation, and Liability Act of 1980 is conducted in 11 groundwater operable units. The purpose of this monitoring is to define and track plumes and to monitor the effectiveness of interim remedial actions. Interim groundwater remediation in the 100 Areas continued with the goal of reducing the amount of chromium (100-K, 100-D, and 100-H) and strontium-90 (100-N) reaching the Columbia River. The objective of two interim remediation systems in the 200 West Area is to prevent the spread of carbon tetrachloride and technetium-99/uranium plumes. Resource Conservation and Recovery Act of 1976 groundwater monitoring continued at 25 waste management areas during fiscal year 2005: 15 under interim or final status detection programs and data indicate that they are not adversely affecting groundwater, 8 under interim status groundwater quality assessment programs to assess contamination, and 2 under final status corrective-action programs. During calendar year 2005, drillers completed 27 new monitoring wells, and decommissioned (filled with grout) 115 unneeded wells. Vadose zone monitoring, characterization, and remediation continued in fiscal year 2005. Remediation and associated monitoring continued at a soil-vapor extraction system in the 200 West Area, which removes gaseous carbon tetrachloride from the vadose zone. DOE uses geophysical methods to monitor potential movement of contamination beneath former waste sites.« less

Authors:
; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
889070
Report Number(s):
PNNL-15670
830403000; TRN: US200619%%352
DOE Contract Number:
AC05-76RL01830
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; CARBON 14; CARBON TETRACHLORIDE; CESIUM 137; CHROMIUM; COLUMBIA RIVER; CONTAMINATION; IODINE 129; MONITORING; QUALITY ASSURANCE; REMEDIAL ACTION; RESOURCE CONSERVATION; STRONTIUM 90; TECHNETIUM 99; TRITIUM; WASTE MANAGEMENT; GROUND WATER; groundwater, Hanford, vadose zone, modeling, characterization

Citation Formats

Hartman, Mary J., Morasch, Launa F., and Webber, William D.. Hanford Site Groundwater Monitoring for Fiscal Year 2005. United States: N. p., 2006. Web. doi:10.2172/889070.
Hartman, Mary J., Morasch, Launa F., & Webber, William D.. Hanford Site Groundwater Monitoring for Fiscal Year 2005. United States. doi:10.2172/889070.
Hartman, Mary J., Morasch, Launa F., and Webber, William D.. Tue . "Hanford Site Groundwater Monitoring for Fiscal Year 2005". United States. doi:10.2172/889070. https://www.osti.gov/servlets/purl/889070.
@article{osti_889070,
title = {Hanford Site Groundwater Monitoring for Fiscal Year 2005},
author = {Hartman, Mary J. and Morasch, Launa F. and Webber, William D.},
abstractNote = {This report is one of the major products and deliverables of the Groundwater Remediation and Closure Assessment Projects detailed work plan for FY 2006, and reflects the requirements of The Groundwater Performance Assessment Project Quality Assurance Plan (PNNL-15014). This report presents the results of groundwater and vadose zone monitoring and remediation for fiscal year 2005 on the U.S. Department of Energy's Hanford Site, Washington. The most extensive contaminant plumes in groundwater are tritium, iodine-129, and nitrate, which all had multiple sources and are very mobile in groundwater. The largest portions of these plumes are migrating from the central Hanford Site to the southeast, toward the Columbia River. Carbon tetrachloride and associated organic constituents form a relatively large plume beneath the west-central part of the Hanford Site. Hexavalent chromium is present in plumes beneath the reactor areas along the river and beneath the central part of the site. Strontium-90 exceeds standards beneath all but one of the reactor areas. Technetium-99 and uranium plumes exceeding standards are present in the 200 Areas. A uranium plume underlies the 300 Area. Minor contaminant plumes with concentrations greater than standards include carbon-14, cesium-137, cis-1,2-dichloroethene, cyanide, fluoride, plutonium, and trichloroethene. Monitoring for the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 is conducted in 11 groundwater operable units. The purpose of this monitoring is to define and track plumes and to monitor the effectiveness of interim remedial actions. Interim groundwater remediation in the 100 Areas continued with the goal of reducing the amount of chromium (100-K, 100-D, and 100-H) and strontium-90 (100-N) reaching the Columbia River. The objective of two interim remediation systems in the 200 West Area is to prevent the spread of carbon tetrachloride and technetium-99/uranium plumes. Resource Conservation and Recovery Act of 1976 groundwater monitoring continued at 25 waste management areas during fiscal year 2005: 15 under interim or final status detection programs and data indicate that they are not adversely affecting groundwater, 8 under interim status groundwater quality assessment programs to assess contamination, and 2 under final status corrective-action programs. During calendar year 2005, drillers completed 27 new monitoring wells, and decommissioned (filled with grout) 115 unneeded wells. Vadose zone monitoring, characterization, and remediation continued in fiscal year 2005. Remediation and associated monitoring continued at a soil-vapor extraction system in the 200 West Area, which removes gaseous carbon tetrachloride from the vadose zone. DOE uses geophysical methods to monitor potential movement of contamination beneath former waste sites.},
doi = {10.2172/889070},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Feb 28 00:00:00 EST 2006},
month = {Tue Feb 28 00:00:00 EST 2006}
}

Technical Report:

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  • This is a summary booklet of the main report: Hanford Site Groundwater Monitoring for Fiscal Year 2005. It is the summary section of the main report with a CD of the entire report included. The main report is one of the major products and deliverables of the Groundwater Remediation and Closure Assessment Projects detailed work plan for FY 2006, and reflects the requirements of The Groundwater Performance Assessment Project Quality Assurance Plan (PNNL-15014). This report presents the results of groundwater and vadose zone monitoring and remediation for fiscal year 2005 on the U.S. Department of Energy’s Hanford Site, Washington. Themore » most extensive contaminant plumes in groundwater are tritium, iodine-129, and nitrate, which all had multiple sources and are very mobile in groundwater. The largest portions of these plumes are migrating from the central Hanford Site to the southeast, toward the Columbia River. Carbon tetrachloride and associated organic constituents form a relatively large plume beneath the west-central part of the Hanford Site. Hexavalent chromium is present in plumes beneath the reactor areas along the river and beneath the central part of the site. Strontium-90 exceeds standards beneath all but one of the reactor areas. Technetium-99 and uranium plumes exceeding standards are present in the 200 Areas. A uranium plume underlies the 300 Area. Minor contaminant plumes with concentrations greater than standards include carbon-14, cesium-137, cis-1,2-dichloroethene, cyanide, fluoride, plutonium, and trichloroethene. Monitoring for the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 is conducted in 11 groundwater operable units. The purpose of this monitoring is to define and track plumes and to monitor the effectiveness of interim remedial actions. Interim groundwater remediation in the 100 Areas continued with the goal of reducing the amount of chromium (100-K, 100-D, and 100-H) and strontium-90 (100-N) reaching the Columbia River. The objective of two interim remediation systems in the 200 West Area is to prevent the spread of carbon tetrachloride and technetium-99/uranium plumes. Resource Conservation and Recovery Act of 1976 groundwater monitoring continued at 25 waste management areas during fiscal year 2005: 15 under interim or final status detection programs and data indicate that they are not adversely affecting groundwater, 8 under interim status groundwater quality assessment programs to assess contamination, and 2 under final status corrective-action programs. During calendar year 2005, drillers completed 27 new monitoring wells, and decommissioned (filled with grout) 115 unneeded wells. Vadose zone monitoring, characterization, and remediation continued in fiscal year 2005. Remediation and associated monitoring continued at a soil-vapor extraction system in the 200 West Area, which removes gaseous carbon tetrachloride from the vadose zone. DOE uses geophysical methods to monitor potential movement of contamination beneath former waste sites.« less
  • Groundwater is monitored in hundreds of wells at the Hanford Site to fulfill a variety of requirements. Separate monitoring plans are prepared for various purposes, but sampling is coordinated and data are shared among users. DOE manages these activities through the Hanford Groundwater Performance Assessment Project, which is the responsibility of Pacific Northwest National Laboratory. The groundwater project integrates monitoring for various objectives into a single sampling schedule to avoid redundancy of effort and to improve efficiency of sample collection.This report documents the purposes and objectives of groundwater monitoring at the DOE Hanford Site in southeastern Washington State.
  • The Hanford Site 200 Area Effluent Treatment Facility (ETF) processes contaminated liquids derived from Hanford Site facilities. The clean water generated by these processes is occasionally enriched in tritium, and is discharged to the 200 Area State Approved Land Disposal Site (SALDS). Groundwater monitoring for tritium and other constituents is required by the state-issued permit at 22 wells surrounding the facility. Water level measurements in nearby wells indicate that a small hydraulic mound exists around the SALDS facility as a result of discharges. This feature is directing groundwater flow radially outward a short distance before the regional northeasterly flow predominates.more » Evaluation of this condition indicates that the networks currently adequate for tracking potential effects of the SALDS on the groundwater. During FY 2000, average tritium activities inmost wells declined from average activities in 1999. The exceptions are deep well 699-48-77C, where tritium results reached a maximum value of 710,000 pCi/L as a result of the delayed penetration of effluent deeper into the aquifer, and in well 299-W7-3, along the northern boundary of the 200 West Area, which has apparently been affected for the first time by the SALDS tritium plume, with a tritium activity of 1,400 pCi/L measured in August 2000. Of the 12 constituents with permit enforcement limits, which are monitored in SALDS proximal wells, all were within groundwater limitations during FY 2000. The arrival of tritium at well 299-W7-3 demonstrates excellent agreement with the current numerical groundwater model, by virtue of both arrival time and predicted tritium concentration. Analyses for conductivity, total dissolved solids, sulfate, chloride, sulfate, dissolved calcium, and dissolved sodium indicate that well 699-48-77A and, to a lesser extent, well 699-48-77D show the effects of dilute effluent entering groundwater, resulting in a depression of concentrations of these constituents below natural background levels. Recommendations for future monitoring include temporarily increasing the frequency of tritium sampling at wells 299-W7-3, 299-W7-5, 299-W7-6, and 299-W7-7 to quarterly. This measure will assist in a more accurate determination of the southern bounds of the SALDS-generated tritium plume, provide estimates of travel time for model comparisons, and help preserve the distinction between this plume and the older 200 West tritium plume further east. Because of the accurate numerical model predictions thus far, reapplication of the model will occur only after a recognizable departure from model predictions is observed through the increased frequency in well monitoring.« less
  • The Hanford Site 200 Area Effluent Treatment Facility (ETF) processes contaminated liquids derived from Hanford Site facilities. The clean water generated by these processes is occasionally enriched in tritium, and is discharged to the 200 Area State Approved Land Disposal Site (SALDS). Groundwater monitoring for tritium and other constituents is required by the state-issued permit at 22 wells surrounding the facility. During FY 2001, tritium activities in the SALDS proximal well 699-48-77A increased (maximum 670,000 pCi/L) as a result of the resumption of tritium disposal in September 2000, following a 16-month hiatus in significant tritium discharges. Well 699-48-77C, where tritiummore » results reached a maximum value of 980,000 pCi/L, is reflecting the result of the delayed penetration of effluent deeper into the aquifer from 1999 SALDS tritium discharges. Speculation in FY 2000 (Barnett 2000b) that tritium may have reached two wells due south of the facility is probably premature. FY 2001 results indicate no departures from historical levels of tritium in these wells.« less
  • Tritium activities decreased in all three SALDS proximal wells during FY 2002, compared with FY 2001. Activities in well 699-48-77A first decreased to less than 3,000 pCi/L in January 2002, but rose to 150,000 in July, probably as a result of tritium discharges to SALDS that resumed in February 2002. Well 699-48-77C, where tritium analysis produced a maximum value of 750,000 pCi/L in January 2002, reflects the result of the delayed penetration of effluent deeper into the aquifer from tritium discharges. SALDS proximal well 699-48-77D produced a maximum result of 240,000 pCi/L in July 2002. Timing between detections of tritiummore » and other constituents in well 699-48-77C suggest a delay of approximately three years from detection in wells 699-48-77A and 699-48-77D. Historically maxima for tritium (790 and 860 pCi/L in successive sample periods) suggest that tritium from SALDS may be reaching the northern edge of the 200 West Area, south of the facility.« less