Radioactive Fish - Part 1
Radioactive Fish - Part 1
Cold war radionuclides from KAPL discharged into the Mohawk River
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 (this one) is focused on the nature of radioactivity discharged into the river primarily between 1950 to 1960. Post 2 (this link) 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 1: Radioactive discharges - 1950-1960
KAPL did a number of experiments that that resulted in radioactive waste as part of the Cold War effort. The facility was developed after World War II in 1946 under a contract between General Electric and the United States government, and it was one of the first laboratories to conduct research on power generation from nuclear reactors. There are two inter-related issues here. One is the nature of the site and one is the way in which discharges from the site have impacted the the Mohawk and Hudson rivers.
According to the NYS DEC, the Separations Process Research Unit (SPRU) at KAPL operated from the late 1940s to the early 1950s and was a production-scale development facility for the Plutonium-Uranium Extraction (PUREX) process developed to extract plutonium from spent (fissioned) nuclear fuel. The SPRU at KAPL is NYS DEC site number 447011, owned by the US Department of Energy, and is being remediated under the Resource Conservation and Recovery Act of 1975. It was originally owned and operated by General Electric.
The SPRU generated liquid wastes rich in fission fragments that were, according to KAPL records now unclassified, diluted and discharged into the Mohawk River. KAPL initiated studies to understand the fate and transport of the radionuclides and to understand the effect on the aquatic environment, including fish. Studies showed that fish took up radionuclides, especially Sr-90, which is primarily taken up in bones because it acts like calcium. Decades after discharge of radionuclides, various studies of sediment cores in the Mohawk and the Hudson revealed the scope of this contamination.
Map showing the location of KAPL in Niskayuna (near Schenectady) in the lower Mohawk watershed in relation to Indian Point on the lower Hudson.
There is quite a bit to unpack here and as I went down this rabbit hole I discovered some amazing things about the amount of radioactive material that was dumped in the River, how the effects on fish were studied, and then how the analysis of sediment cores reveled the extent of sediment contamination. But I also learned that the radioactive sediments are being eroded and exposed in flood events, most recently during Hurricane Irene in 2011.
One of the main research directions in my career has been using radionuclides for dating rocks – including fission fragments. I have also studied the hazards of naturally occurring isotopes in rocks (U, Th, and K) and the source and fate of radon. So I originally thought I was on familiar ground for this project, but I quickly found that I was immersed in a whole new territory when it comes to specific isotopes from the production of plutonium. As a result, this is a long and involved post. Read on if you have time, otherwise bookmark this and come back later.
Recall that elements (such as uranium, strontium, or plutonium) may have different isotopes that have different number of neutrons. Radioactive isotopes decay to daughter isotopes and in the process produce emissions that can be harmful - the rate of decay is commonly expressed as a half life, which is the amount of time for half the parent to decay to its daughter. In a previous post on fish otoliths we explored Sr-87 and Sr-86 and how the Sr-87/Sr-86 ratio can change in different settings. The amount of available Sr-87 reflects rock processes because it is partly radiogenic (slowly produced from decay of Rb-87, but the half-life of this isotope is very long – 4.9 x 10^10 yr or 49,000,000,000 years).
Products of the fission (splitting) of uranium or plutonium include a spectrum of radioisotopes, but fission produces an asymmetric distribution of fragments. The “yield curve” of fission fragments provides the relative fraction of isotopes from the fission process. The two relatively abundant isotopes that are produced: Sr-90 and Cs-137. Cs-137 has a half-life of 30 years, and it undergoes beta decay and transforms to Ba-137, a stable isotope. Sr-90 is a short-lived radioisotope with a half-life of about 30 years. After about five half-lives (about 150 years), virtually all of the parent isotope Sr-90 has decayed to its ultimate daughter, which is Zr-90 - a stable isotope.
Strontium acts like calcium, and thus it is a bone-seeker, meaning that it gets incorporated in bone as a substitute for calcium. In the case of Sr-90, it is a radioactive bone-seeker, adding a radioactive component to bone. We saw in a previous post that strontium can also be incorporated into shells and otoliths.
I decided to break this story down into a rough chronology (and into two parts). Note that some (most) of the activities at KAPL are difficult to determine because they are/were classified, but some have recently been declassified. But the sediments in the Mohawk River are wide open for study, and research on radionuclides in sediment has important implications that transcend published reports released to the public.
1950: Discharging radionuclides in the Mohawk. There is no doubt that significant quantities of radionuclides were dumped in the Mohawk, and the fate of those contaminants is certainly of interest. Some of them ended up in the sediment, some were flushed into the Hudson, and some were taken up by fish and aquatic organisms. At KAPL, GE conducted studies to understand the fate of the contaminant plume in different flow conditions, the deposition or radionuclides in the sediment, and the uptake of radionuclides by fish and other aquatic organisms.
Unclassified biannual summary activities provide a sketch of how profound these releases where – and how they were studied. While the full reports are not available (to me), parts of summaries of activities shed light on the role the Mohawk played in disposal of waste and how monitoring and experimentation was undertaken. A few excerpts from summary reports at the height of activity are worth reading:
July-Dec 1953 – “[activities include studies of] adsorption of fission products on river sediment…”
Jan-June 1953 – “Liquid waste studies during the period include the investigation and recommendation of a proportional sampler for combined sewer effluents and studies of fission product activity on the Mohawk sediment. A discussion of the metering and sampling for the liquid waste discharged into the Mohawk River is included in this report. The adsorption of fission activity on Mohawk River sediment with respect to contact time, laundry detergents, dissolved solids, and the quantity of river sediment was investigated and the data are tabulated. A vegetation analysis for radioruthenium [Ru-106] investigated, and a tentative calculation of the maximum permissible concentrations of activity in vegetation was made.”
July-Dec 1954 – “Liquid waste studies were confined to an analysis of P-32 activity collected on suspended Mohawk River sediment.”
July-Dec 1955 – “Data are tabulated on the concentration of radioactivity in Mohawk River plankton, vegetation, and fish.”
Jan-June 1956 – “A study on the radioactivity of samples of aquatic life in the Mohawk River was continued.”
Jan-June 1957 – “Studies were continued to determine the rate of accumulation and the distribution of radioactive materials in aquatic life as related to radioactive materials released into a surface stream. The data indicate that specimens of fry are the most sensitive specimens of those analyzed with respect to reflecting the transient concentrations of radioactive materials in the stream.”
July-Dec 1957 – “A comparison was made of the levels of radioactivity detected in Mohawk River fish as the levels vary with season or sewage-river-water temperature. To attain data for toxicity evaluations, a metal cage was designed and placed with specimens of carp, bullheads, and sunfish near the knolls site sewer outlet. A buoy-anchor mechanism facilitated the moving of the cage to various depths and locations in the river. The results of this study showed the temperature and density effects on the dispersion of the sewage.”
April-June 1958 – “A total of 5.5 c [curies] of fission products was released to the Mohawk River without adverse effect on the utilization of the river for recreational purposes, power generation, or drinking water supply. Less than 850 mc [millicuries, or 31,450 MBq] of fission products were released to the atmosphere from KAPL exhaust stacks. This represents an increase of two orders of magnitude over the previous reporting period; which is due, for the most part, to an incident in the Radioactive Materials Laboratory.”
Jan-June 1959 – “A total of 4.5 curies [166,500 MBq] of fission product radioactivity was released to the Mohawk River without adverse affect on the utilization of the river water for recreation or as a source of drinking water.”
July-Sept 1960 – “Approximately 31 mc of fission product radioactivity, including < 0.1 mc of I-131 were discharged from the exhaust stack system. Liquid waste discharged to the Mohawk River included 300 mc of fission product radioactivity.
In congressional testimony in early 1959 (see KAPL, 1959 – US Congressional record) it was noted that annual waste production was ~2.7 million gallons, and ~1.8 million gallons of this contained an annual average of ~25 curies, which was released into the Mohawk River after dilution, and that when discharged it does not exceed 1/10 the allowable limit. The primary isotope considered a hazard at the time was Sr-90.
1953: The Simpson radiotracer study. Three radiotracer experiments were done in 1953 and 1954 using P-32, a short-lived isotope commonly used for tagging organisms in biology (Simpson et al., 1958). While KAPL was dumping radionuclide-rich sludge into the Mohawk River, it seems that the general idea was to discharge a constant supply that stayed below threshold levels. But it is clear from the studies that there was a concern that some of the radioactive material was not completely going down the Mohawk because it was being trapped behind the Vischer Ferry dam, a permanent dam only a few kilometers down river from the facility. But also some of it was sinking and accumulating in an abnormally deep and narrow part of the river in front of the facility. So, experiments were set up to determine the flow of sewage plumes, and to monitor these plumes they were dosed with radioactive phosphorus (P-32), which has a short half life (~14 days). This rapid decay and relatively high dose meant that it could be measured and traced by instruments in the field.
Map of the study area from Simpson, Beetem, and Ruggles 1958 paper entitled “Radiotracer experiments in the Mohawk River, New York, to study sewage path and dilution.” In these experiments radioactive P-32 was mixed with sewage, dumped in the Mohawk, and then was detected downriver at Cohoes. These experiments were conducted to determine the fate of radionuclides in the River, but the experiments (or monitoring) did not extend into the Hudson River. The shaded area between KAPL and the Vischer Ferry dam is thought to have the highest concentration of radionuclides in sediment.
Three experiments were conducted using radioactive phosphorous 32 (or P-32) where up to 4 curies of material (see note in Further reading about the Curie) was mixed with sewage and discharged into the Mohawk to study the fate and mixing of contaminants. Some of the sewage sank to the deep pool, and some (most) was carried down the Mohawk and could be detected 20 kilometers downriver at Cohoes. The real reason for these experiments was undoubtedly to determine the fate and transport of radionuclides in waste from the separation process – primarily fission fragments - that were being discharged into the Mohawk.
The word “sewage” is rarely used as a euphemism for anything, but it appears that this is the case in these radiotracer studies because this “sewage” included diluted radioactive waste in addition to normal wastewater from the plant. Bear in mind that there were routine discharges of fission products in wastewater, but then there were additional experiments in which the sewage included large introduced doses of this short-lived radiotracer (P-32).
While the tracer studies were done to see how transport occurred in the Mohawk River, I did not find any indication that studies were made on transport beyond the confluence of the Mohawk with the Hudson River.
1960: Isotopes and fish (OH report). It is possible to get a sense of what specific radionuclides were discharged into the river and the effects on fish by reading reviews of the KAPL projects (I have not been able to get the actual reports, just summaries). One of these papers that reviewed results is by the Aquatic Life Advisory Committee of the Ohio River Valley Water Sanitation Commission (no authorship on this paper –the entire committee is the author).
This advisory committee reviewed radioactive discharges and effects on fish at Hanford (Washington), Oak Ridge (TN), KAPL (NY), and several other sites from reports produced at each facility. They note that the “sewage” from KAPL contained uranium, plutonium, and a range of fission products that were discharged into the River.
According to the OH report, the greatest amount of radioactivity in KAPL discharges was from nuclides of rare earth elements and a significant amount was from strontium-90 [Sr-90], ruthenium-106 [Ru-106], and cesium-137 [Cs-137]. The half life of Ru-106 is 374 days, so since 1960 virtually all of this isotope has decayed to its stable daughter product. However, the half-life of Sr-90 is 28.8 years and Cs-137 is 30.2 years, so about 25% of the original amount remains in the sediment after about 60 years, or two half-lives.
The OH report summarizes studies by KAPL scientists that show bio-accumulation of radioactivity in plankton and fish. Fish examined include shiners (Notropis Cornutus frontalis), but also Shad (Alosa Sapidissima), Bullhead (Ameiurus melas), goldfish (Carasius auratus), and Orange-spotted sunfish (Lepomis humilis). Total radioactivity (beta and gamma) for the fish was between 8 x 10^-6 and 80 x 10^-6 uc/g (microcurie per gram) – the highest levels of radioactivity were in the bones of the fish. In White Oak Lake adjacent to the Oak Ridge (TN) facility, Sr-90 in the bones accounted for 80% of the radioactivity in the fish, and thus one can infer that this was also likely the case with Mohawk fish. Recall that strontium acts like calcium, and is thus a bone-seeker, as discussed above. For the fish in the Mohawk, they note:
Because they have a long half-life and are relatively abundant in fission-product mixtures, Sr-90 and Cs-137 are the isotopes most likely to be important in the pollution of streams with mixed fission products…. No report was made of the isotopic distribution in the [fish] tissue, but uranium, plutonium, the radiostrontium isotopes, and radiocerium are known to accumulate in bone. It is probable that the radioactivity of soft tissues was caused chiefly by isotopes of the rare earth elements and cesium (see p. 78).
Total radioactivity (d/m/gm) of fish (fry or young of the year) in the Mohawk at KAPL (KAPL data). Although the original plot is labeled “live fish,” it is hard to imagine “fry with stomach and intestinal content removed” as “live.” In this time period the highest releases from KAPL into the Mohawk was in 1958, and they note that increases in released radioactivity corresponds to increases in uptake in fish fry. Data from KAPL submission to the US Congressional Hearing of the Joint Committee on Atomic Energy, 86th Congress, 28 Jan to 3 Feb 1959, and this figure is redrafted from that report (see KAPL, 1959, p. 799, fig 3).
[ This story has been divided into two separate posts - Radioactive Fish - Part 1 (this one) and Radioactive Fish - Part 2 (mainly about recent sediment cores). ]
This and other Notes from a Watershed are available at: https://mohawk.substack.com/
Further Reading and Notes
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