PUBLIC HEALTH ASSESSMENT
PADUCAH GASEOUS DIFFUSION PLANT (U.S. DOE)
PADUCAH, MCCRACKEN COUNTY, KENTUCKY
Contaminants released from PGDP to air andwater may accumulate in plants and animals,which are collectively referred to as biota.Many of these plants and animals are importantsources of human nutrition. As such peoplewho consume them may be potentially exposedto chemical and radioactive substances. In thissection, we focus on complete or potentialhuman exposure pathways (biota consumed by humans).
DOE began monitoring biota near PGDP in 1955, sampling broadleaf grass for fluorides .DOE's results were published in the site annual reports beginning in 1958 . Sampling locationsand collection frequencies varied over the years. In 1994, DOE stopped sampling broadleaf grasses. They began off-site sampling and radiological analyses of edible wildlife and gardenvegetables in 1984 . Fish sampling for plutonium 239, technetium 99, and uranium isotopesbegan in 1985 . DOE began sampling local milk and food crops in 1988 and added animaltissue from wild animals in the Western Kentucky Wildlife Management Area (WKWMA) in 1989[55,56].
The Kentucky Department for Environmental Protection and the Kentucky Department for PublicHealth also collect and analyze biota samples near PGDP. In many cases, DOE and the stateagencies split samples in order to validate their results. These state agencies also work closely withWKWMA personnel in this effort.
ATSDR scientists evaluated biota data contained in the site annual environmental reports, specialstudy reports, and the PGDP and Commonwealth of Kentucky environmental databases. Thedatabases include biota samples collected from 1989 through 1999. The data include 22,180measurements of 150 different chemical and radioactive substances in 22 types of biota [45,85].
Chemical and radioactive contaminants have been measured in samples of fish (e.g., sunfish, bass,carp, and catfish), game, green beans, soybeans, nuts, corn, apples, persimmons, and other fruits andvegetables collected near PGDP [45,85]. DOE and the State agencies have sampled fish fromseveral locations in Bayou and Little Bayou Creeks and in nearby ponds and lakes. They sampledgame animals, including deer, rabbit, quail, raccoon, and squirrel, primarily from the WKWMA.Background fish samples were collected from Hinds Creek and background deer samples from theLand Between the Lakes. Exact sample locations have changed over time [62,55,56,46,47,48].Food crop were sampled from mainly residential locations (approximately 89 locations). Locationsand station names have changed over time [62,55,56,45,46,47,48].
ATSDR scientists used screening techniques to focus the evaluation only on contaminants that maybe a human health hazard for biota exposure pathways. First, we evaluated analytical data todetermine maximum or average concentrations for the following chemical contaminants in biota:(1) metals, including aluminum, arsenic, barium, beryllium, cadmium, chromium, copper, lead,manganese, mercury, nickel, selenium, silver, uranium, vanadium, and zinc; (2) fluoride; and (3)polychlorinated biphenyls (PCBs). Concentrations of metals and fluoride in biota are in Table18A(1), and concentrations of PCBs in biota are in Table 18A(2). We also evaluated data for thefollowing radioactive contaminants in biota: technetium 99, uranium 234, uranium 235, uranium238, thorium 230, plutonium 239, americium 241, neptunium 237, strontium 90, and cesium 137.Concentrations of radioactive contaminants in biota are in Table 17B.
Since there were many types of biota sampled, we grouped similar types into categories:
|Biota Category||Possible Biota Types in Category|
|Fish||Bass, catfish, sunfish, carp, creek chub|
|Game||Deer, quail, rabbits, raccoons, squirrels|
|Nuts, legumes||Walnuts, soy beans, green beans|
|Yellow vegetables||Corn, squash, carrots, eggplants, mixed vegetables|
|Green vegetables||Cabbages, cucumbers, peas, peppers (and broadleaf grass for fluoride only)|
For categories with more than one biota type (e.g., yellow vegetables), we averaged the maximum concentration for each type in the category. For fish, we averaged PCB concentrations within and over fish species to reflect fishing and consumption patterns. ATSDR also assumed a 30% skinning/trimming/cooking loss associated with PCBs. (Studies have reported PCB reductions ranging from 14 to 80% due to skinning, trimming, or cooking fish .) Not all contaminants have been analyzed for each biota type (e.g., green vegetables and grapes were analyzed only for radioactive contaminants). Overall, there were sufficient data to evaluate most contaminants in each category, with a couple of notable exceptions.
PGDP has emitted significant quantities of fluoride, but the electronic database does not contain data for fluoride in biota. In the late 1950s and early 1960s, average fluoride levels in off-site broadleaf grass exceeded Kentucky's Ambient Air Quality Standard for fluoride in forage . (4) In 1959, the average fluoride level in broadleaf grass samples collected 0.5 miles east of the security fence was 50.6 micrograms of fluoride per gram of grass (µg/g), reported as a dry weight concentration. For purposes of estimating human exposure doses, we converted this fluoride concentration to a wet concentration, assuming a 50% moisture content: the result was a wet weight concentration of 25.3 µg/g. We assumed that wet weight concentration was present in off-site green vegetables. These conservative assumptions would probably overestimate the dose.
Two bass samples in Gravel Pit Pond contained mercury at 5 to 10 times the level found in other bass, sunfish, and catfish samples near PGDP. We believe that these samples do not represent mercury levels typically found in bass near PGDP. The two samples were not used in the mercury evaluation and are not included in Table 18A(1). However, someone who ate only bass from the Gravel Pit Pond for an extended period of time might experience adverse health effects.
Annual environmental reports and special studies indicate that PCBs are present in fish collected from Bayou and Little Bayou creeks and other surface water sources. By the end of 1988, PCBs were detected in fish tissue samples from Little Bayou Creek and from Outfall #11 on the east side of the site . For this reason, DOE started monitoring PCB levels in fish in the area. PCB results from the 1989 DOE environmental report indicates that the highest concentrations were found in fish tissue collected from the Outfall #11/Little Bayou Creek sampling location. Total PCB levels were more than three times the average level detected in fish from the remainder of Little Bayou Creek and almost 20 times greater than total PCB levels detected in fish from Bayou Creek. This means that, in the time covered by the 1989 report, total PCB concentrations detected in fish tissue from Little Bayou Creek (as a whole) were approximately five times greater than concentrations detected in fish tissue from Bayou Creek .
According to the Oak Ridge National Laboratory (ORNL) report on biological monitoring at PDGP for 1993-1994, average total PCB concentrations in fish tissue are approximately 10 times lower than the concentrations given in the PGDP 1989 report [96,56]. Also, the ORNL report listed total PCB levels in fish tissue from Little Bayou Creek as approximately four times greater than concentrations detected in fish tissue from Bayou Creek.
In September 1997, the University of Kentucky collected and analyzed fish samples from the Bayou Creek system and found that concentrations were similar to concentrations detected in the ORNL report for 1993-1994 [94,96]. This suggests that PCB concentrations are stabilizing in fish from Little Bayou Creek.
|Nut, legume||Green bean||Unknown||ND||ND||ND||ND||1.2||12.8||0.7||3.3||ND||6.40||ND||8.10|
|1 Concentrations are maximums from 1987-2000 electronic databases, except AVERAGE, which is the average of maximums in a group. Other exceptions are indicated. |
2 Concentration is maximum from UK study, Analysis of Mercury in Stream Water, Sediment and Fish from Bayou Creek System; however, bass sample from gravel pit pond not used (see narrative) .
3 Average concentration in broadleaf grass at location with highest annual average, Environmental Monitoring Summary for the Paducah Plant for 1959 .
A blank cell means no valid analyses were conducted.
|Key: Al = aluminum; As = arsenic; Ba = barium; Be = beryllium; Cd = cadmium; Cr = chromium; Cu = copper; F = fluorine; Pb = lead; Mn = manganese; Hg = mercury; Ni = nickel; Se = selenium; Ag = silver; U = uranium; V = vanadium; Zn = zinc; ND = not detected or no samples had concentrations above analytical detection limits|
Little Bayou Creek
Other: Little Bayou Creek
|Aroclor 1254||Total PCBs1||Aroclor 1254||Total PCBs1||Aroclor 1254||Total PCBs1|
|Fish (all species)||19892||Tissue||2.196||4.843||0.477||1.02||7.63||17.95|
|1 "Total PCBs" is the total concentration for Aroclors 1248, 1254, and 1260. |
2 PGDP environmental report for 1989 .
3 ORNL report, December 1993 to December 1994 .
4 Report to FFOU on Polychlorinated Biphenyl (PCB) Residue in Fish From the Bayou Creek System .
5 DOE's electronic information management system database from 1987 to 2000 . Only one sample had a detection level of 0.05 ppm. Other results were reported as non-detections; however, the detection levels were generally 0.05 ppm or higher.
Note: Data were also reviewed from DOE and Kentucky Biological Monitoring Program Reports and the University of Kentucky's 1998 study; however, the results were substantially lower than the results above. In August 1997, the University of Kentucky also collected and analyzed deer tissue (liver, fat, muscle, and mammary tissue), but detected no Aroclor 1248, 1254, or 1260.
|Key: µg/g = micrograms per gram; ppm = parts per million; PCBs = polychlorinated biphenyls; WKWMA = Western Kentucky Wildlife Management Area|
|Nut, legume||Green bean/soybean||Unknown||17.2||0.005||0.003||0.001||0.001||0.000||0.001|
|Yellow vegetable||Mixed vegetables||Unknown||0.14||0.005||0.002||0.001||0.002||0.000||0.000|
|1 Concentrations are the maximum values from DOE's 1987-2000 electronic database, except AVERAGE, which is the average of maximum in a group. Other exceptions are indicated. |
2 Concentrations are the maximum values from Kentucky's Analytical Draft Report for Deer Harvest 2000 .
4. Kentucky's Ambient Air Quality Standard for fluoride in cattle forage was 25 micrograms of fluoride per gram of forage (µg/g) in 1962. In 1992, the standard was changed to a maximum of 40 µg/g averaged over the growing season, 60 µg/g averaged over 2 months, and 80 µg/g averaged over any one month.