Accumulation of Radioactivity in Columbia River Fish in the Vicinity of the Hanford Works

Page 1

RADIOLOG I i SCIENCES DEPARTMENT COLUMBIA RIVER FISH IN THE VICINITY OF THE HANFORD WORKS HANFORDWORKS RICHLAND. WASH INGTON THIS DOCUMENT IS PUBLICLY

Page 2

Experimental Biology and Medicine This document consists of 117 copies, Series Radiological Sciences Dept. Operated for the Atomic Energy Commission by the General Electric Company under Contract # W-31-109-Eng-52

Page 4

Experimental Biology and Medicine 1 2 1 - 28 - Argonne National Laboratory 30 - Army Chemical Center 31 - 33 - Atomic Energy Commission, Washington 34 - 36 - Brookhaven National Laboratory ‘ e 37 - Bureau of Medicine and Surgery 39 - 50 - Carbide and Carbon Chemicals Company (ORNL) 55 - Chicago Patent Group 63 - Hanford Operations Office 64 - Iowa State College 73 - 75 - New York Operations Office 76 - Patent Branch, Washington 77 - Public Health Service 78 - Savannah River Operations Office (Augusta) 79 - USAF Radiation Laboratory 81 - UCLA Medical Research Laboratory (Warren) 82 - 85 - University of California Radiation Laboratory 86 - 87 - University of Rochester 89 - University of Washington 94 - 100 - Wright A i r Development Center 101 - 115 - Technical Information Service, Oak Ridge 1 1 7 - Surgeon General, Department of the Army - Carbide and Carbon Chemicals Company (K-25 Plant) - Carbide and Carbon Chemicals Company (Y-12 Area) - Chief of Naval Research - Knolls Atomic Power Laboratory - Naval Medical Research Institute

Page 5

The data obtained from the radioassay of fish collected in vicin- .. ity of the Hanford Works between April, 1948 and June, 1950 are presented. Most of the radioactivity in the fish resulted from the concentration of P32 in the scales, bone, and certain visceral organs. The level of activity density in the fish was influenced by size, feeding habits and metabolic rate in addition to the activity density of the water. Changes in operation of nuclear reactors have resulted in progressive increases in activity densities of fish from one year to the next. levels of radioactivity a r e not sufficiently high to be hazardous to either the fish o r persons eating them.

Page 6

LIST OF ILLUSTRATIONS Figure 4a. Ratio of activity densities of various tissues Figure 4b. Ratio of activity densities of various tissues Figure 4c. Ratio of activity densities of various tissues Figure 5. Comparison of activity density of livers of various Figure 6. Seasonal variation in activity density of large fish as

Page 7

LIST OF ILLUSTRATIONS (CONTINUED) Absorption curve f o r radioactivity of speckled dace Comparison of activity densities of various species Seasonal variation in activity densities of juvenile Radioactivity of small fish in the Columbia River Activity densities of livers and scales of coarseRelationship between the activity densities of scales Relationship between the activity densities of the livers of whitefish and squawfish and those of the Method of computing the ratio of the radioactivity of squawfish livers to that of coarse-scaled sucker Method of computing monthly average activity Radioactive contamination of small fish in the Columbia River in the vicinity of Hanford in the vicinity of the Hanford Works

Page 8

ACCUMULATION OF RADIOACTIVITY IN COLUMBIA RIVER FISH IN THE VICINITY Water of the Columbia River which is diverted through the nuclear reactors for cooling purposes becomes radioactive from the neutron bombardment of elements dissolved in the water and from corrosion products washed from the surfaces of the tubes and slugs within the piles. The characteristics of this radioactivity have been studied by the Technical Section (1) and by the Radiological Sciences Department (2) , (3). Further studies a r e currently in progress. The contamination resulting from the discharge of the radioactive cooling water into the Columbia River is studied by the Radiological Sciences Department; physical aspects of the problem a r e assigned to the Control Unit of the Biophysics Section and biological aspects a r e assigned to the Aquatic Biology Unit of the Biology Section. Studies on the accumulation of radioactivity in fish of the Columbia River began in May of 1946 with repetitive collections of adult fish from five stations located between Priest Rapids and the 300 Area and with collection of some control specimens from the Yakima River. The results of this work were reported by Herde (4). on large fish, undertaken between April 1947 and April 1948, was confined to the vicinity of Hanford. Work on other limnological phases was started in the fall of 1947 by Coopey (6). Since April 1948, routine collection of large fish in the vicinity of Hanford has been continued and in October 1949, routine collection of small fish from nine localities between Priest Rapids and McNary Dam was initiated. The results obtained from these fish samples collected between April 1948, and June 1950, a r e * F o r orientation map see Figure 11, page 3 1 .

Page 9

presented here. The t e r m gtlargefish*' is applied to those forms which exceeded five grams in weight, although the great majority weighed between 200 and 1000 grams, and were captured by gill net o r set line. Q Such fish were usually adults and were dissected in order that individual tissues and organs could be assayed. to those forms which were l e s s than five grams in weight, usually captured by a small hand seine, and assayed a s whole specimens, oras The term llsmall fish" is applied Results of studies on other aquatic forms are being reported MATERIALS AND METHODS Capture of Specimens Sampling gill nets were used during the greater part of the year to capture the large fish. These nets were made in five sections, each section being 2 5 feet in length and five feet deep, but varying in size of mesh from three-quarter to two inch square measure. sized mesh was s e t nearest shore. capturing fish of a particular size range so that all kinds and sizes from about 10 centimeters to about 90 centimeters in length were taken. The nets were usually placed in a small eddy area immediately upstream from the Hanford F e r r y landing and were set from a rubber boat. (Figure 1). One o r two nets w e r e set, depending on the availability of the fish, and allowed to remain in the river over night since these nets catch fish most efficiently in the dark. every two weeks. Each size of mesh was efficient for Fishing was carried on once Set lines w e r e used in addition to the gill nets during the cold winter months when the fish w e r e relatively sluggish and only meager numbers could be captured. The set lines consisted of a series of

Page 11

baited hooks on short lines which in turn w e r e attached to a common ground line 15 to 50 feet long. weighted to sink it to the bottom, the other was attached to a float. bu€k of the s e t line catches consisted of squawfish and a few cottoids, both carnivorous forms. (Figure 2). One end of the line was < -\ Table 1 is a two year summary by months of the large fish catch Classification of the fish and common names are according This table indicates roughly the availability of the fish to the gear used and is not intended a s a measure of relative abundance, since sometimes one net would be set, other times two, and the success of a fishing spot would vary with river height and water conditions. Small fish were captured in the inshore area by the use of a small traps and with dip nets. out once every two weeks. During the winter a few were captured in small Fishing at each station was routinely carried Shiners (Richardsonius balteatus balteatus) and small squawfish (Ptychocheilus oregonensis) were captured in greatest numbers and were taken throughout the year. Dace, (mostly Apocope oscula were also frequently taken depending on the sampling location, and juvenile chinook salmon (Oncorhynchus tschawytscha) were obtained in abundance during the spring. A few small specimens of the following species w e r e also, analyzed: shad (Alosa sapidissima) (one specimen only sent to us from Bonneville Dam), sticklebacks (Gasterosteus aculeatus) chiselmouth (Acrocheilus alutaceus), whitefish ( Prosopium williamsoni) sunfish (mostly Helioperca incisor), bass (Micropterus dolomieu) and larval lampreys o r ammocoetes (presumably Entosphenus

Page 15

In addition to the collections by the Hanford Works group, fish for sampling were sent up bi-weekly from Bonneville Dam, located approximately 225 miles down river from the pile areas. Bonneville was carried out by a resident biologist through the cooperation of the United States Army Engineers. were small; however, parts of larger fish, principally sturgeon, were Most of the fish thus obtained Preparation and Radioassay of Samples *An effort was made to determine the activity density of the following organs and tissues from at least one specimen of each species of large fish caught on each sampling date: scales, muscle, liver, bone, gills, and feces. In order that a s many fish a s possible could be analyzed, however, often only the scales, muscle, and liver of duplicate specimens were assayed. Scales were selected because they usually had the highest activity density and because they represented calcareous tissue; liver was selected because of the large number of samples on this organ and because it was considered representative of the visceral organs; muscle was selected because it is used for food by humans. occasion such other tissues as ovary o r testis (especially when near maturity), kidney, heart, stomach, intestine, spleen, blood, stomach content, fins, eye and brain were sampled. During 1948 the skin was sampled quite consistently, but this was discontinued in 1949 since there w a s wide variation in activity density between the connective tissue of the dermal layers and the calcareous tissue of the scales. Small fish w e r e sampled whole and not dissected. Often two o r more specimens of the same species were processed as a unit in order to obtain the desired mass of tissue. From April to early November 1948, samples were prepared for radioassay by reducing them to an ash on 1 1 / 2 inch stainless steel plates * Activity density is the of a mixture of radioisotopes per unit mass and is expressed

Page 16

with the u s e of nitric acid and heat described by Herde (8). method, weights of sampled tissues usually ranged between one and three grams. Subsequently, samples of the tissues weighing from 0.3 to 0 . 7 grams were merely macerated and uniformly spread on the plates, and there dried under infra-red lamps, a method which appeared to give at least 20 per cent higher counting rates, and required considerable less The continued use of nitric acid was found advisable with bone Plates containing the dried samples were mounted on cardboard holders , covered with cellophane and counted with thin mica-window direct count of the residue from an evaporated 500 ml. sample. Counts were corrected for background, sample source size, and counter geomNo correction for decay was made in the case of the fish samples, however, since the great majority were counted within six hours after they w e r e taken from the river, and the radioactivity appeared to be almost entirely from P32 with a half-life of 14.3 days. In view of the high energy of these beta particles, and the relatively small s i z e s of the samples, l o s s due to self-absorption amounted to considerably less than 10 per cent, and corrections for this loss were not made. The activity density of the samples has been expressed in t e r m s of microcuries per gram of wet o r live weight. The beta emitters in the water samples were measured by Water counts were corrected for decay. Samples of less than 0 . 1 0 g were not used because of the difficulty of getting proper plate coverage, and because counting rates from such small samples frequently were not appreciably above background. The reliable e r r o r * in such cases was actually equal to o r greater than the counting rate which consequently was highly questionable. * Reliable e r r o r is taken a s the 90 per cent fiducial interval based on theoretical fluctuations in counting rate.

Page 17

Although a total of 1621 samples a r e included in this analysis, 1 they are distributed over a period of more than two years, among 13 species of fish, and 20 types of tissue. pected to fluctuate in several ways and in order to follow trends o r make comparisons, special treatment of the data was necessary. The purpose of such treatment was to include a s many observations a s possible in each comparison so that a reasonable estimate of activity density levels might 'be attained. The following factors had to be considered, correlated, and consolidated if possible: (1) variations in activity density between different tissues, (2) variations in activity density between species, and (3) variations in activity density with season. specimens of large fish were captured in one locality, geographic variations did not need to be considered. The methods used in handling the data in order to consolidate a s many of the observations as possible a r e described in the appendix. The activity densities would be exSince all of the Variations in activity densities between different tissues The relative activity densities of the various tissues sampled from Samples13 different species of fish a r e shown in Figures 4a, 4b, and 4c. in which the reliable e r r o r exceeded 50 per cent of the counting rate were not used. In every case the activity density of the liver has been s e t at 100 and the relative activity density of the other tissues expressed a s a percentage. The parenthetical value preceeding the name of the tissue represents the number of comparisons which were made to obtain that particular ratio. The species a r e roughly grouped by feeding habits # with two exceptions necessitated by the spacing of the histograms. Figure 4a includes the suckers and chiselmouth which feed principally on the bottom sediment o r periphyton and associated small forms of animal life.

Page 20

SMALL MOUTH BASS COT TO ID FIGURE 4c RATIO OF ACTIVITY DENSITIES OF

Page 21

Figure 4b includes chubs, carp, and whitefish, which on the whole appear to be bottom feeders, but exercise more selection in their feeding habits since they prefer animal food; this group should also include the sturgeon. Figure 4c includes the small mouth bass, squawfish, and cottoids which are more carnivorous in their feeding habits. The silver troutor landlocked blueback salmon (Oncorhynchus nerka) and the shiner should also be included in this group. suckers, chiselmouth, squawfish, and whitefish a r e more reliable than the others since the majority of specimens captured were of these species. The histograms for the coarse and fine-scaled The relative …