Leaching of copper from contaminated soil following the application of EDTA. I. Repacked soil experiments and a model

Soil Research ◽  
2003 ◽  
Vol 41 (2) ◽  
pp. 323 ◽  
Author(s):  
T. Thayalakumaran ◽  
I. Vogeler ◽  
D. R. Scotter ◽  
H. J. Percival ◽  
B. H. Robinson ◽  
...  

The EDTA-enhanced remediation of copper contaminated sandy-loam soil of volcanic origin was investigated. The soil, from an orchard, was contaminated with about 250 mg/kg of copper due to the extensive use of copper sprays. Copper-contaminated soil was packed into 100-mm-long columns, and solutions of Na2H2EDTA with CaCl2, raised to a pH of 6.2, were applied at a flow rate of 24 mm/h. Application of an excess of 0.01 M EDTA leached about half the acid-extractable copper from the soil; most of it coming out in the first 3 liquid-filled pore volumes (PV). Also a 0.5 PV pulse of 0.001 M EDTA was applied to similar soil columns and then either leached immediately with 0.005 M CaCl2, or left for periods of up to 1 month before leaching. With immediate leaching, 70% of the EDTA applied was complexed with copper in the leachate, but after a month's delay only 24% was complexed with copper in the leachate, the rest being complexed with iron. There was no evidence of EDTA retardation or adsorption. The experimental results were simulated using the convection–dispersion equation, incorporating a source/sink term. This described the competing time-dependent reactions of copper and iron with EDTA, and the reversion of CuEDTA2– to adsorbed Cu2+ and Fe(III)EDTA– in solution. Reasonable simulations were achieved, mostly within errors of observation.


2004 ◽  
Vol 3 (1) ◽  
pp. 316
Author(s):  
M. Saleem Akhtar ◽  
Tammo S. Steenhuis ◽  
Brian K. Richards ◽  
Murray B. McBride


1985 ◽  
Vol 17 (10) ◽  
pp. 197-199 ◽  
Author(s):  
P. H. Jørgensen

In two different unsaturated soil columns percolated with artificial rainwater under simulated aerated conditions, transport of coxsackievirus B3 and adenovirus 1 below 3.5 cm under the soil surface could not be demonstrated. The viruses were applied to the columns as seeded sewage sludge. Under saturated conditions transport of water-suspended coxsackievirus B3 was faster in a soil column with sandy loam soil than in a diluvial sand column.



Soil Research ◽  
1998 ◽  
Vol 36 (6) ◽  
pp. 963 ◽  
Author(s):  
R. E. White ◽  
L. K. Heng ◽  
G. N. Magesan

Nitrate (NO-3 ) concentrations in 0·5-mm increments of drainage from adjacent mole- and pipe-drained paddocks of a silt loam soil under pasture near Palmerston North, New Zealand, were measured during 2 winters. The data were simulated using a simple analytical transfer function model (TFM). Urea fertiliser applied at the rate of 120 kg N/ha to one paddock was treated as a pulse input to the pool of resident soil NO-3. A source{sink term was included for plant uptake and net mineralisation (including any effect of denitrification). During the first winter (1990), a TFM using either a 1-parameter Burns probability density function (pdf) for solute travel, or a 2-parameter lognormal pdf, satisfactorily simulated the NO-3 concentration trends and predicted the total amounts of N leached. The pdf parameters were derived from previous chloride leaching data for this site. The best-fit value for the transport volume θst, the key parameter in the Burns pdf, was set at 0·37 m3 /m3 in 1990, as used in previous modelling of sulfate leaching. However, a value of 0 ·25 m3 /m3 in the Burns pdf gave better simulations of the 1991 data. This was probably due to more intense rain events during the early part of the drainage season in 1991 compared with 1990, which resulted in more preferential flow through the soil and a lower value for θst. The simulations for both years showed that ≥50% of the total leachable NO-3 was retained in the soil, despite normal winter drainage of about 300 mm. Ideally, the appropriate value of st should be determined by independent measurement. It may need to be adjusted according to the likely incidence of preferential flow early in the winter when NO-3 concentrations are highest. Provided the average initial soil NO-3 concentration can be estimated and a net source{sink term defined, the amount of NO-3 leached in drained soils can be satisfactorily modelled using the TFM approach with a 1-parameter pdf. Duplex soils which have a fluctuating watertable in the A horizon over an impermeable B horizon may prove to be an analogous system.



Weed Science ◽  
1977 ◽  
Vol 25 (4) ◽  
pp. 304-308 ◽  
Author(s):  
F.E. Brockman ◽  
W.B. Duke

The degradation and leaching of methazole [2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione] and metabolites in Elmwood sandy loam soil over time in response to average spring environmental conditions was studied by using soil columns placed on a rainfall simulator in an environmental growth chamber. Methazole was degraded to 3-(3,4-dichlorophenyl)-1-methylurea (DCPMU) and 3-(3,4-dichlorophenyl) urea (DCPU) over a 6-week period following methazole application, during which the soil columns received simulated rainfall of 1.27 cm every fourth day. Methazole level decreased to 27% of the original amount while DCPMU and DCPU levels increased to 53% and 1%, respectively. Of the total radioactivity remaining in the soil columns after 44 days and after 14 cm rainfall, approximately 80% remained above a depth of 6.35 mm.



1988 ◽  
Vol 111 (1) ◽  
pp. 159-163 ◽  
Author(s):  
R. S. Siyag ◽  
M. S. Lamba ◽  
Raj Pal ◽  
S. R. Poonia

SummaryDepth accumulation of exchangeable Na+ was measured in Ca-saturated sandy loam soil columns (length 50 cm; diameter 5 cm) after percolating 500, 1000, 1500 and 2000 ml of 013 M Na+, as NaCl, NaHCO3, Na2SO4 and Na2CO3 solutions. The values of exchangeable sodium percentage (ESP) increased gradually with the increase in the volumes of the solution percolated. Two conceptual layer models, based on whether solutions were added to the topmost soil layer in one lot (M-I) or in splits equal to the saturation deficit (M-II), were used to predict the depth distribution of ESP of soil. The chemical processes considered in the models were the formation of ion pairs and the exchange equilibria of Na+ and Ca2+. The predicted values of ESP were considerably higher for model M-II than model M-I. The consideration of ion-pair formation and the accompanying anion had only negligible effect on the predicted ESP. The model M-II over-predicted the experimental ESP throughout the soil columns, whereas the model M-I under-predicted it for the upper layer(s) and over-predicted for the lower layers. On the basis of average ESP of the whole columns, the less realistic model M-I predicted experimental results better than model M-II. This was attributed to the presence of mobile and immobile zones for the flowing solutions.



Weed Science ◽  
1975 ◽  
Vol 23 (6) ◽  
pp. 454-457 ◽  
Author(s):  
Chu-Huang Wu ◽  
Normie Buehring ◽  
J. M. Davidson ◽  
P. W. Santelmann

Soil columns and soil thin-layer chromatography were used to evaluate the mobility of napropamide [2-(α-naphthoxy)-N,N,-diethylpropionamide] in various soils. The surface-applied herbicide did not move deeper than approximately 6 cm in a Teller sandy loam soil after a water application of 10.2 cm. The Rfvalues for napropamide and two reference herbicides were in the order of fluometuron [1,1-dimethyl-3-(α,α,α-trifluoro-m-tolyl)urea] > napropamide > terbutryn [2-(tert-butylamino)-4-(ethylamino)-6-(methylthio)-s-triazine]. The mobility of each herbicide was reduced with an increase in clay and organic matter content. Carbon-14 ring labeled napropamide was used to determine the adsorption and desorption characteristics of the herbicide in various soils. The Rfvalues obtained with napropamide and each soil agreed with the adsorptive characteristics. Small applications of a muck soil to a sand (2%, w/w) significantly increased herbicide adsorption and decreased herbicide desorption.



1998 ◽  
Vol 27 (6) ◽  
pp. 1495-1503 ◽  
Author(s):  
H. Jonge ◽  
O. H. Jacobsen ◽  
L. W. Jonge ◽  
P. Moldrup


Weed Science ◽  
1999 ◽  
Vol 47 (3) ◽  
pp. 349-352 ◽  
Author(s):  
Chris H. Tingle ◽  
David R. Shaw ◽  
Patrick D. Gerard

Laboratory studies were conducted to evaluate14C-flumetsulam mobility in two Mississippi soils of varied texture and organic matter content following delays in irrigation. Mobility was evaluated using packed soil columns, 25 cm deep, under unsaturated–saturated flow conditions. Irrigation timings included 0, 3, and 5 d after flumetsulam application. Flumetsulam mobility (defined as the amount collected in leachate) decreased from 45% to no more than 20% of the applied in the Prentiss sandy loam soil when irrigation was delayed 3 or 5 d. With the Okolona soil, flumetsulam recovery in the leachate was 21, 14, and 6%, respectively when irrigation occurred 0, 3, and 5 d after application. Flumetsulam proved to be mobile when irrigation immediately followed application, with 6 to 45% recovered in the leachate from all soils evaluated. The Prentiss soil retained 6% of the applied flumetsulam in the upper 5 cm and the Okolona soil retained 22% when irrigation immediately followed flumetsulam application. When the irrigation interval was delayed at least 3 d, the Okolona soil retained 40% in the upper 5 cm, whereas the Prentiss soil retained 10%. Flumetsulam mobility was dependent on irrigation timing and soil type.



2004 ◽  
Vol 3 (1) ◽  
pp. 316-316
Author(s):  
M. Saleem Akhtar ◽  
Tammo S. Steenhuis ◽  
Brian K. Richards ◽  
Murray B. McBride


1981 ◽  
Vol 61 (2) ◽  
pp. 401-407 ◽  
Author(s):  
E. J. HOGUE ◽  
A. GAUNCE ◽  
S. U. KHAN

The mobility of four residual orchard herbicides, diuron, dichlobenil, simazine and terbacil was compared in soil columns using a sandy loam and loam soil common to the Okanagan Valley. Mobility for all herbicides was greater in the sandy loam than loam soil. Dichlobenil was least mobile in the soil columns followed by diuron, simazine then terbacil. No dichlobenil was leached through the 30-cm sandy loam soil column with 120 cm of water but 40 cm of water leached more than half of the terbacil. More dichlobenil was converted to the water-soluble 2,6-dichlorobenzamide in the loam soil than in the sandy soil. This metabolite is water-soluble and was partially leached through the loam soil column with the highest level of irrigation.



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