FIGURE 1. The Hanford Site. HGP = Hanford Generating Project; Redox = reduction-oxidation; PUREX = 
plutonium uranium extraction; WPPSS = Washington Public Power Supply System; FFTF = Fast Flux Test 
Facility. 
Thus, air is sampled continuously for airborne 
particulates and analyzed for radionuclides at 
50 locations onsite, at the Site perimeter, and 
in nearby and distant communities (Jaquish and 
Bryce, 1989). At selected locations, gases and 
vapors are also collected and analyzed. Many of 
the longer-lived radionuclides released at 
Hanford are also present in atmospheric fallout 
that resulted from nuclear weapons testing in the 
1950s and 1960s or from nuclear accidents that 
occurred elsewhere. 
In May and June, 1986, air samples collected 
onsite as well as those from distant locations 
showed increases in several long- and short-lived 
radionuclides (e.g., 137 Cs, 131 I l03 Ru) that re 
sulted from the reactor accident at Chernobyl, 
April 1986, in western Russia. However, even 
then, no sample exceeded 0.17% of the applicable 
DOE derived concentration guide (DCG) for areas 
permanently occupied by the public (PNL, 1987). 
Ground Water 
The shallow unconfined (water-table) aquifer has 
been affected by waste-water disposal practices 
at Hanford more than the deeper, confined aqui 
fers. Discharge of water from various indus 
trial processes has created ground-water mounds 
near each of the major waste-water disposal faci 
lities in the 200 Areas, and in the 100 and 
300 Areas (Figure 1). Discharge to ground water 
in the 200 Areas may contribute ten times more 
water annually to the unconfined aquifer than 
natural input from precipitation and irrigation 
(Graham et al., 1981). These ground-water mounds 
have altered local flow patterns in the uncon 
fined aquifer, which are generally from west to 
east. 
Ground water, primarily from the unconfined 
aquifer, is currently sampled from over 550 wells 
and analyzed for radionuclides (Jaquish and Bryce, 
1989). Tritium ( 3 H) occurs at relatively high 
levels in the unconfined aquifer, is one of the 
most mobile radionuclides, and thus, reflects the 
extent of ground-water contamination from onsite 
operations. Many liquid wastes discharged to the 
ground at Hanford have contained 3 H. The PUREX 
facility is currently the main source for 
3 H-containing wastes (DOE, 1983). Tritium from 
releases prior to 1983 that passed downward 
through the vadose (unsaturated) zone to the 
unconfined aquifer continues to move with ground- 
water flow toward the Columbia River. Tritium 
concentrations in Hanford ground water range from 
less than 300 pCi/L to over 2,000,000 pCi/L near 
or within the 200 Areas (PNL, 1987; Jaquish and 
Mitchell, 1988; Jaquish and Bryce, 1989). 
Ground water from the unconfined aquifer enters 
the river through subsurface flow and springs that 
emanate from the riverbank. McCormack and Carl ile 
(1984) identified 115 springs along a 41-mile 
stretch of river. Tritium concentrations in 
wells near the springs ranged from 19,000 to 
250,000 pCi/L and averaged 176,000 pCi/L in 1985 
(Price, 1986). Although the distribution of 3 H 
and other radionuclide concentrations in springs 
generally reflected those in nearby ground-water 
wells, the magnitude was generally less in springs 
due to mixing of ground and surface water. 
Tritium concentrations in the river were generally 
less than those in springs. Tritium concentra 
tions in springs were less than 4% of the DOE DCG 
(2,000,000 pCi/L). Tritium concentrations in the 
river near the springs were less than 0.5% of the 
DCG and less than half the regulatory limit for 
drinking water (20,000 pC1/L) (EPA, 1976). From