Suspension From Soil at Higher Wind speeds

DOE-HDBK-3010-94

3.0 Liquids; Aqueous Solutions

3.2.4.4

S u s pen sion F rom S oil at H igh er W in d s peed s

Aerodynamic entrainment (resuspension) at higher air velocities for UNH solution from

various surfaces was measured in wind tunnel experiments (Mishima and Schwendiman,

August 1973). Measurements were made at velocities of 2.5 mph and 20 to 23 mph at 1 ft

above the surface of smooth, sandy soil. The experimental apparatus and measured values

are shown in Figure A.3 and Table A.3 in Appendix A. The pertinent data are listed in

Table 3-11.

Table 3-11. M easured ARFs and Rfs of Uranium (UNH) From

Soil at 2.5 m ph and ~20 m ph

(Table III - M ishim a and Schwendim an, August 1973)

W indspeed,

Sam pling

Rate

Substrate

ARF

m ph

Tim e, hr

Fraction/hr

Soil

2.5

5.0E-4

0.76

9.0E-5

1.0E-4

0.84

4.0E-6

4.0E-4

0.63

1.0E-5

The ARF for 1 m/s (5E-4 in 6-hr, airborne suspension rate of 9E-5/hr) bounds the measured

ARFs. The suspension rates from soil at both windspeeds for the remaining two datapoints

appear to be approximately the same value (4E-6/hr vice 1E-5/hr). The two measurements at

1.0 m/s show more variation than the measurements for the two different windspeeds. In

keeping with typical resuspension assumptions, the RF of the airborne material is

conservatively assumed to be 1.0.

3.2.4.5

B ou n d in g A sses s men ts

For liquids inside buildings or other confinements, the effective airflows experienced are not

considered comparable to extremes such as high external wind. The experiment involving

suspension of liquids from shallow pools of concentrated heavy metal salt solutions on

stainless steel (Mishima, Schwendiman, and Radasch, November 1986) produced extremely

low estimates of aerodynamic entrainment in the range of 1E-11/hr to 1E-10/hr. Even the

spray release from large outdoor pond values would not exceed a value of 4E-7/hr for 5m/s

windspeed, and would be expected to be considerably less. Examining the results of Sehmal

and Lloyd (1976 a,b), this study would expect a resuspension rate for liquids to be 4E-7/hr

or less.

Based on the above considerations, a conservative ARR of 4E-7/hr is assigned for:

(1) liquids indoors on heterogenous surfaces (e.g., stainless steel, concrete) exposed to forced

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