Environ. Sci. Technol. 1980, 23, 814-820
LRH = In (RH) LTP = In (TP) LTR = In (TR) LAT = In (AT + c ) , c = 2.0 for winter seasons, c = 4.0 for summer seasons Registry No. CO,630-08-0.
LRH LTP LTR LAT
Literature Cited (1) McCleary, R.;Nienstedt,B. C. Time Series Analyais of the Impact of the Vehicle Emissions Inspection Program (I/M) on Ambient Air Quality in Phoenix and Tucson. Report to the Auditor General, State of Arizona, 1983. (2) Tiao, G.C.; Liu, L.-M.; Hudak, G. B. Statistical Analysis of Aerometric Data to h s s the Effect of the Arizona I/M Program on Ambient Quality in Phoenix, Airzona. Final Report to EPA under Contract 68-02-3513, 1984.
(3) Tiao, G.C.;Box, G. E. Po;Hamming, W. J. J. Air. Pollut. Control Assoc. 1975,25, 1130. (4) Tiao, G. C.;Hillmer, S. C. Enuiron. Sci. Technol. 1978,12, 820. ( 5 ) Ledolter, J.; Tiao, G. C. Enuiron. Sci. Technol. 1979, 13,
1233. (6) Tiao, G. C.; Ledolter, J.; Hudak, G. B. Enuiron. Sci. Technol. 1982, 16, 328. (7) Box, G. E. P.; Tiao, G. C. J.Am. Stat. Assoc. 1976, 70,70. (8) Liu, L.-M.;Hudak, G. B.; Box, G. E. P.; Muller, M. E.; Tho, G. C. The SCA Statistical System: Reference Manual for Forecasting and Time Series Analysis; Scientific Computing Associates: P.O. Box 625, DeKalb, IL 60115,1986. Received for review March 21,1988. Accepted October 18,1988. This research was supported by EPA Contract 68-02-3513.
Nonequiiibrium Sorption during Displacement of Hydrophobic Organic Chemicals and 45Cathrough Soil Columns with Aqueous and Mixed Solvents Peter Nkedl-Klzza,” Mark L. Brusseau, P. Suresh C. Reo, and Arthur G. Hornsby Soil Science Department, University of Florida, Gainesville, Florida 32611-015 1
A series of miscible displacement experiments was conducted to investigate the significance of intraorganic matter diffusion (IOMD) as the rate-limiting step in sorption of organic and inorganic solutes during steady water flow in soil columns. Displacement studies were performed using Eustis surface soil and the same soil treated with hydrogen peroxide to reduce soil organic carbon content from 0.2% to
A b u h
10
8
0.6
a
0
0
A .
n
t
Y
.
J
0.6
f
'n.0
0
a,,;,
,
,
1
0
2
,
,
,
,
4
3
,
5
I
t
6
01 0
PORE VOLUMES (p) a @%a
1
B
. y
h
I
1
'
I
'
I
'
2
'
'
I
3
Relative Pore Volumes (PA?)
O u u - -
.A
'@-.
00 O
i' 0.6
-
8 J
0.6
-
e- 0.4
-
f
0 PI
d 8 ,
,
,
,
.
,
,
I
2 3 4 5 PORE VOLUMES (p) Figure 2. Similar to Figure 1 except the soil is H,O,-treated. 0
0.2 -
1
The BTCs obtained from a simultaneous displacement of diuron or atrazine, W a , and tritiated water through the soil columns (experiments 1and 2) are presented in Figure 1. Note that, while the BTCs for tritiated water and W a
are symmetrical and sigmoidal in shape, the BTCs for W a are rotated clockwise in comparison to the BTC for tritiated water; this suggests increased dispersion of Wa In contrast, the BTCs for both diuron and atrazine are asymmetrical,with pronounced tailing in approach to C* = 1. Tailing or increased dispersion is typical for BTCs
0
1
2
3
Relative Pore Volumes (PA?) Flgum 4. Normalized BTCs for q20,atrazine, and %a for untreated and H,02-treated soil (A and B, respectively).
obtained under nonequilibrium conditions (6). The fact that only the BTCs for the sorbing solutes exhibit increased dispersion or asymmetry suggests that the mechanism responsible for nonequilibrium is related to the sorption process. To investigate the role of sorbent organic matter in nonequilibrium sorption, the solutes were displaced through columns packed with Eustis soil for which the OC Environ. Sci. Technol., Voi. 23,No. 7, 1989 817
. A
2
A+
0.4
i.HO
a
RELATIVE PORE VOLUMES (PA?) 1
t $
0.8
v
0.6
t
0 0
0.4
F 4:
d a
0.2 0
1
0
2
3
RELATIVE PORE VOLUMES (pit?) Figure 5. BTCs for 3H20and diuron (A) and 3H20and atrazine (B)in methanol-water mixtures.
1
06
,
N*
-
082
1
0 '
2
0
4
6
10
8
Pore Volumes (p)
1
-t v
0.8
j
0.6
f
0.4
s 0
P
:0.2 I o
-
0
1 '
2
l
'
4
l
'
l
'
6
8
l
'
'
10
12
Pore Volumes (p)
Figure 6. Observed and calculated (line) BTCs for 3H20,diuron, and "Ca (A) and 3H20, atrazine, and '%a
(B).
content was reduced to
