Radioactive Fish - Part 2
KAPL discharges of radioactivity well-represented in sediment cores
Over the last seven decades a plume of radioactive material has emanated from the Knolls Atomic Power Laboratory (KAPL) on the lower Mohawk in Niskayuna, NY. The plume is recorded in river sediments that include radioactive isotopes of uranium, plutonium, strontium, cesium, and more. The distinctive isotopic signature of this plume has been identified in sediments in the tidal Hudson River near New York City, 200 km downstream. This is known to be the largest single point source of radioactivity in the Mohawk-Hudson Watershed. This story, which is divided into two separate posts, explores the origin and identification of that radioactivity now present in the sediments of the Mohawk and Hudson rivers. Post 1 (link here) is focused on the nature of radioactivity discharged into the river primarily between 1950 to 1960. Post 2 (this one) is primarily focused on analysis of radioactivity of sediment cores taken from the Mohawk and Hudson rivers and on cleanup activities, mainly between 1990 and 2018.
PART 2: Radioactive sediment cores and Clean up issues
2002-2005: Sediment Cores. Full analysis of cores of river sediment provide a more detailed picture of the distribution of radionuclides. Thomas Kenna and Steve Chilrud at Lamont-Doherty Earth Observatory (LDEO) in New York took sediment cores from the Mohawk and the Hudson to determine the extent and origin of radionuclides. They published their first findings in 2002, and then expanded findings with other colleagues in 2004 and 2005. The results are stunning because they document distinct radionuclides in the Mohawk River from KAPL (nearly the same sites cored by KAPL in 1992), and that these same radionuclides have been transported over 200 km down the river to the tidal Hudson near NYC.
Sediment deposits can be complicated because they record mixing of different sediment sources. The authors explain that sediments in the Hudson have three primary sources of radionuclides: 1) global fallout from nuclear detonations, which occurred in the 1950s and peaked in the early 1960s, involving mainly plutonium (Pu), neptunium (Np), and cesium (Cs); 2) releases and discharge from the Knolls Atomic Power Laboratory on the Mohawk River (Cs-137 and other radionuclides of uncertain proportions); and 3) the Indian Point Nuclear Power Plant (IPNPP) (mainly Cs-137). Global fallout can be identified several ways, but they use known ratios of plutonium and neptunium to identify whether contamination is from fallout or KAPL (they use Pu-240/Pu-239, Np-237/Pu-239 and Pu-241/Pu-239 as measured by mass spectrometry, which here was by ICPMS analyses).
The authors know the ratios of these radionuclides from KAPL because they analyzed sediment cores from the Mohawk River one kilometer down river from the plant. They also cored river sediment from the Hudson in two places: one upriver from the confluence of the Mohawk and one in close proximity to Indian Point (IPNPP) on the lower Hudson River. As anticipated, sediments from the sediment core from the Hudson River taken above the confluence of the Mohawk had a global fallout signal – this site is up river from both KAPL and IPNPP, and hence the only signal it should have is from global fallout. Fallout is a long story, but considerable fallout in NY was from above ground testing done in Nevada (and elsewhere) prior to the Partial Nuclear Test Ban Treaty of 1963.
The other two cores had radionuclides – and ratios of radionuclides - indicative of a non-fallout source of radioactivity. The location of the Mohawk sediment cores is positioned such that it captures the downstream signal of radionuclide contamination from KAPL. What is stunning is that the sediment core from near Indian Point appears to be a mix between the global fallout signal and that distinctive signal from KAPL on the Mohawk. If their interpretation is correct, radionuclides released into the Mohawk from KAPL were transported and preserved in sediments 200 km downriver, just up river from NYC. In all likelihood radionuclides from KAPL made it as far as NYC, but this analysis has not been done as far as I know.
In 2004, the authors and additional colleagues continued this research with a focus on plutonium isotopes (Pu-239, Pu-240), neptunium (Np-237) and cesium (Cs-137). They note that many of these radionuclides tend to be bound to fine-grained sediments such as mud and silt. They show that the Mohawk sediments downstream from KAPL have elevated levels of Pu-239, Pu-240, and Cs-137 and that these isotopes can be identified in the Hudson. In 2005 they wrote:
Contamination derived from activities at KAPL present in Mohawk River sediments is a chronic source of contamination to sediments at all sites sampled in the Hudson River Estuary, indicating transport distances of greater than 200 km. In a sediment core collected in the Mohawk River - 1 km downstream of KAPL, we observe 137 Cs, 239 Pu, and 240 Pu inventories 1-2 orders of magnitude greater than those expected from global fallout deposition.
So according to these studies, sediments in the Mohawk include isotopes of plutonium, specifically Pu-239 and Pu-240. Pu-239 has a half life of 24,100 yr, and Pu-240 has a half life of 6,500 yr. Logic would suggest that the greatest load of these radionuclides is caught up in sediments between KAPL and the Vischer Ferry dam (Lock E7).
2010 Spill in the Mohawk. DOE awarded a $69 million cleanup contract for the SPRU site (and related sites on the KAPL property), and work began in 2008. The contaminated material that was removed is in 22 containers that are still onsite, and according to a recent story by Brian Nearing at the Times Union these drums will be on site indefinitely. In October 2010 the accidental spill of contaminated water occurred during cleanup as part of the decontamination process. A letter from the DEC to the contractor noted that the 630 gallons of water containing plutonium, uranium, strontium (Sr-90) and cesium (Cs-137), spilled and flowed into the Mohawk River (see 2010 Daily Gazette and NY Times stories).
The EPA notes that four potential exposure pathways for the contamination at this site are surface water, groundwater, sediment, and soil. The “potential receptors” are: 1) Mohawk River users (through recreation and drinking water); 2) terrestrial and aquatic biota; and 3) employees and residents in the area. Current discharges to the Mohawk River are regulated under a permit issued by NYS DEC, but the issue is really the legacy from the past.
2011 Harpenau verification survey. Cleanup of part of the KAPL site occurred between 2008 and 2010 (as noted above), and this cleanup was monitored by a third party, which was researchers from Oak Ridge National Laboratory. The Harpenau report is a verification survey of the contractor work done after clean up occurred at several sites related to the SPRU. The report submitted to the Department of Energy (DOE) on 15 March 2011 was approved for public release. The authors note that decommissioning of the SPRU site began in 1953 and continued through the 1990s, but analysis and cleanup continue. The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) requires that contaminated sites are evaluated and remediated. One stated goal of the KAPL effort is to reduce or eliminate future chemical or radiological releases from the contaminated sites.
Highest concentrations of Cs-137 revealed by gamma mapping with a handheld device at the SPRU site included surface gamma values as high as 25,000 to 27,000 cpm (using a 2x2 cm NaI detector). They used gamma spectrometry in the laboratory to measure Co-60, Cs-137, Eu-152, Eu-154, and Eu-155 in soil samples. The analyses also focused on determination of Am-241, Pu-238, Pu-239/240, U-234, U-235, U-238 (which were measured by alpha spectrometry in the lab). The primary heavy metal of concern in the soil is arsenic, which was measured at concentrations of 4 to 170 mg/kg (EPA regulatory limit for soils is 0.39 mg/kg). In general it would appear from the report that the site benefitted tremendously from cleanup.
The Vischer Ferry dam is a permanent dam below the KAPL site that was built over 100 years ago. This is the site of Lock E7, which has a 27-foot lift. Sediment has accumulated behind the dam and the quiet water on the upriver side is where sediment core MO-7p was taken (Photo: JI Garver, Oct. 2019).
2016 Sediment Core from Lock 7. The most comprehensive recent sediment core analyses are those of William Skorski, who worked with Professor Richard Bopp at Rensselaer Polytechnic Institute (RPI) in Troy NY. Skorski submitted his MSc thesis in 2016 at RPI entitled “Radionuclide in Mohawk River sediments: Atmospheric inputs, Knolls Atomic Power Laboratory, and tracing scour events.” His thesis detailed the Cs-137 profile of eight sediment cores from the Mohawk River from above the Vischer Ferry Dam (near KAPL), at Colonie Town Park, and at the Crescent Bridge (“Twin Bridges”). The sediment core with the highest levels of radioactivity (here measured by Cs-137) is MO-7p, a core previously taken (but analyzed by Skorski) from a small, protected pool above Lock E7 (Vischer Ferry dam – see photo) 2.75 kilometers downriver from KAPL.
Several important findings come out of Skorski’s study. First he shows that the sediment cores in the Mohawk River below KAPL have very high levels of radioactivity that are essentially part of a contaminated sediment plume from KAPL. He also shows that the distribution of Cs-137 in sediment cores reveal episodic scour and reworking of the radioactive sediment, and he points to the 1964 ice jam event, flooding in 1977, as well as flooding and erosion that may have occurred during Hurricane Irene in 2011. The distribution of radionuclides in the sediment cores indicate that erosion and re-deposition of radionuclides has occurred repeatedly.
Radioactivity of core MO-7p taken in a small enclosed and protected pool above Lock E7. This sediment core was analyzed and evaluated by Skorski as part of his MSc thesis at RPI in 2016. The figure above is modified from his Figure 8.
Two cesium peaks in the core from just above the Vischer Ferry Dam (see figure above) are attributed to KAPL discharge in ~1963 and 1957 and they account for a 33 cm-thick layer of contaminated sediment. Skorski concludes that the proximity of the core to KAPL undoubtedly means that this core reflects the “pipe effluent” for discharges into the River. Of all the cores analyzed in the Mohawk, this core had the highest levels of radioactive contamination, by far. Bear in mind that cesium is the tracer used here, and there is good reason to suspect that these sediments host a range of radioactive fission products, not just cesium (cesium is relatively easy to measure using gamma spectrometry).
Concluding thoughts
Were discharges of radioactive waste into the Mohawk River legal? Did they violate the 1899 Refuse Act that prohibits discharge of waste into navigable waters of the US?
In the submitted testimony to US Congress in 1959, KAPL documents noted that early in the history of the Laboratory and in the initial phases of designing and implementing waste disposal into the River, the Atomic Energy Commission and General Electric recognized the “need for contact” with NY Department of Health and the City of Schenectady. As such, they established the Mohawk River Advisory Committee, which first met on 30 October 1952. Subsequent meetings were held to discuss disposal of radioactive material in the River. The five-person committee included three members from the NY Department of Health (Commissioner, Deputy Commissioner, and Director of Environmental Sanitation), the Executive Secretary of the NY State Pollution Control Board, and a former manager of the City of Schenectady. “In all of its activities, this committee has provided advice and counsel on matters relating to the release of radioactive waste to surface streams.”
In his paper entitled: “Crimes against water: the Rivers and Harbors Act of 1899,” Andrew Franz, Professor of Criminal Justice at the University of Pittsburgh, explains that the Rivers and Harbors Act of 1899 (RHA), often referred to at the Refuse Act, made it “unlawful for any person or corporation to throw, discharge, or deposit any refuse matter of any kind or description from any …manufacturing establishment… into the navigable waters of the United States or their tributaries … without a permit, or in violation of a permit. In clearest terms, the RHA reflects that water pollution is a crime.” One question that emerges here is to what extent the RHA applies to the discharges of radioactive material into the Mohawk River by KAPL.
What’s next in this this saga? The lower part of the Mohawk River has legacy contamination by radionuclides that are caught up in the sediment. Some of those radionuclides have long half-lives and will remain in the sediment for a very long time, unless disturbed. Scour and reworking during floods means that the legacy layer is not buried and out of the the way: it is being mobilized. Future flooding, dredging, and operations at the sites most affected , especially the Niskayuna pool above the Vischer Ferry dam (Lock E7), will have to contend with this issue for years to come.
[ This story has been divided into two separate posts - Radioactive Fish - 1 (here) and Radioactive Fish - 2 (this one). ]
This and other Notes from a Watershed are available at: https://mohawk.substack.com/
Further Reading and Notes (for both posts)
1953-1958 - KAPL reports (several), see notes below.
1958 - Simpson, E.S., Beetem, W.A., and Ruggles, F.H., 1958. Radiotracer experiments in the Mohawk River, New York, to study sewage path and dilution. Transactions, American Geophysical Union, v. 39, n. 3, p. 427-433.
1959 - KAPL. Knolls Atomic Power Laboratory Staff, 1959. “Waste management operations”. In Hearings before the Special Subcommittee on Radiation of the Joint Committee on Atomic Energy. 86th Congress, First Session on Industrial Radioactive Waste Disposal. US Government Printing office. v.1., p. 768-811.
1959 - Simpson, E.S., Beetem, W.A., Ruggles, F.H., Jr, and others, 1959. Hydrologic and tracer studies in Mohawk River at Knolls Atomic Power Laboratory. SO-45 UC-70 Radioactive Waste. US Geological Survey. Unpublished and unclassified report. (see Simpson et al., 1958 above).
1960 - Feinberg, R.J. comp.,1960, 10-31-1960 Health Physics quarterly report for July-Sept 1960 compiled by Feinberg, R.J. comp., KAPL report KAPL-M-HP-6
1960 - Aquatic Life Advisory Committee of the Ohio River Valley Water Sanitation Commission. "Aquatic Life Water Quality Criteria: Third Progress Report." Journal (Water Pollution Control Federation ) 32, no. 1 (1960): 65-82. www.jstor.org/stable/25034061.
1964 - Davies, S., 1964. New York's radiation control system. Public Health Reports, 79(4), p.333.
1999 - KAPL Environmental monitoring report, Calendar Year 1999. KAPL-4843, UC-41, Health and Safety. 149 p.
1999 - KAPL, 1999. Industrial radioactive Waste Disposal – Hearings before the special subcommittee on Radiation of the Joint Committee on Atomic Energy – US Congress of the United States, 86th congress, First session on Industrial Radioactive waste disposal – January 28, 29, and 30, and Feb 2 and 3 1959, v. 1. See “statements for the Record” - Knolls Atomic Power Laboratory staff, “Waste management operations. p. 768-811.
2002 - Kenna, T.C., and Chillrud, S.N., 2002. Identifying sources of non-fallout nuclear contamination of Hudson River sediments by Plutonium and Neptunium isotopic ratios. Am. Geophysical Union, Dec. 2002.
2004 - Kenna, T.C., Chillrud, S.N., Chaky, D.A., Simpson, H.J., McHugh, C.M., Shuster, E.L., and Bopp, R.F., 2004. Determining Sources and Transport of Nuclear Contamination in Hudson River Sediments with Plutonium, Neptunium, and Cesium isotope ratios. American Geophysical Union, 2004.
2005 - Kenna, T.C., Chillrud, S.N., Chaky, D.A., Simpson, H.J., McHugh, C.M., Shuster, E.L., and Bopp, R.F., 2005. Tracing non-fallout nuclear contamination in Hudson River sediments with Plutonium, neptunium, and cesium isotope ratios: sources and transport. 2005/3/16
2006 - Bopp, R.F., Chillrud, S.N., Shuster, E.L. and Simpson, H.J., 2006. 26 Contaminant Chronologies from Hudson River Sedimentary Records. The Hudson River Estuary, p. 383.
2010 - New York Times - Radioactive Material Leaks Into Mohawk River (no by line)
2010 - Franz, A., 2010. Crimes against water: the Rivers and Harbors Act of 1899. Tulane Environmental Law Journal, V. 23, n. 2, Changing Currents: Perspectives on the State of Water Law and Policy in the 21st century. p. 255-278.
2013 (last update) US EPA - Hazardous Waste Cleanup: USDOE Knolls Atomic Power Laboratory in Niskayuna, New York - EPA Notice about corrective actions taken due to the spill at KAPL.
2016 - Skorski, W.B. 2006. Radionuclide in Mohawk River sediments: Atmospheric inputs, Knolls Atomic Power Laboratory, and tracing Scour events. Project submitted for Master of Science, Rensselaer Polytechnic Institute. 65 p.
2018 - Albany Times Union - Radioactive Knolls waste could remain years in Niskayuna - Brian Nearing - June 5, 2018
Notes:
(1) One curie is 37,000,000,000 Bq or 3.7 x 10^10 Bq or 37 GBq. It is a non-SI unit defined in 1910 after initial studies on the activity of radium. It represents 3.7 x 10^10 decays per second. A Becquerel is one decay per second. In the Three Mile Island accident, it is estimated that 13-17 Ci of radioiodine (I-131) was released that may have resulted in thyroid cancer downwind. 2.4 to 13 MCi were released in the accident, the vast majority was radioactive noble gases (Kr and Xe). Note that the total release of I-131 is disputed, see the analysis in the book by Wasserman and Solomon entitled “Killing our own - The disaster of America’s Experiment with atomic radiation” Delta Books, 1982.
(2) An annotated bibliography of unclassified reports on current waste processing and disposal practices (Voress and others 1958). This report has summaries and bi-annual reports from KAPL and many other facilities across the US up to 1958. They include:
135 RADIOLOGICAL DEVELOPMENT ACTIVITIES IN HEALTH PHYSICS Semiannual Progress Report for January June 1956 LJ Cherubin and JJ Fitzgerald 45p KAPL 1615
133 RADIOLOGICAL DEVELOPMENT ACTIVITIES IN THE HEALTH PHYSICS UNIT Semiannual Progress Report for July December 1955 LJ Cherubin and JJ Fitzgerald Changed from OFFICIAL USE ONLY June 3 1957 52p KAPL 1572
124 RADIOLOGICAL DEVELOPMENT ACTIVITIES IN HEALTH PHYSICS UNIT Semiannual Progress for July December 1953 Changed from OFFICIAL ONLY June 3 1957 44p KAPL 1099
128 RADIOLOGICAL DEVELOPMENT ACTIVITIES IN THE HEALTH PHYSICS UNIT Semiannual Progress Report for July December 1954 Changed from OFFICIAL USE ONLY June 3 1957 26p KAPL 1313
122 RADIOLOGICAL DEVELOPMENT ACTIVITIES IN THE HEALTH PHYSICS UNIT Semiannual Progress Report for January June 1953 Changed from OFFICIAL USE ONLY June 3 1957 33p KAPL 997
All above (133, 124, 128, 122) can be read here: Voress, H.E., Davis, T.F., and Hubbard, T.N., Jr. 1958. Radioactive Waste processing and Disposal – A bibliography of selected report literature, US AEC.
(3) Other unclassified documents are available from the U.S. Department of Energy Office of Scientific and Technical Information (OSTI). https://www.osti.gov
Feinberg, R.J., 1959. SEMIANNUAL PROGRESS REPORT OF RADIOLOGICAL DEVELOPMENT ACTIVITIES IN HEALTH PHYSICS FOR JULY-DECEMBER 1957 (No. KAPL-2031). Knolls Atomic Power Lab., Schenectady, NY. See