Silty-clay

The fact that is not radioactive means that it can be used safely in experiments in the field, but it also means that much patient work is needed to obtain results. The approach is demanding in terms of time, equipment, and skilled manpower, but it has made a great contribution to the understanding of the nitrate problem. The results that are outlined here are from experiments made by staff at Rothamsted, but key contributions have also come from Scotland and France. " The majority of the Rothamsted experiments involved winter wheat, but oilseed rape, potatoes, beans, and sugar beet were also grown. The soil is a factor in nitrate leaching, and three types were used, the flinty, silty clay loam at Rothamsted, a sandy loam at Woburn in Bedfordshire and a heavy sandy clay at Saxmimdham in Suffolk. 

Norfolk sandy loam Lakeland sandy loam Hagerstown silty clay loam Barnes clay loam Celeryville muck... 

Figure 2. Persistence of TCDD in Hagerstown silty clay loam at 1, 10, 100 ppm and sampled after 20, 40, 80, 160, and 350 days...

Figure 2. Vapor diffusion of Butylate on sandy loam and silty clay loam.

In Prairie silty clay loam (Figure 4), the mobility of all three herbicides was greatly reduced due to the soils high organic matter content (8.2%). Most of the applied radioactivity was found in the upper 10 cm of the column for each compound. 

Sand Sandy Loam Silty Clay Loam... 

The kinetics of transformation of Mn and Fe among soil fractions is related to the redox potential (Eh changes) as well as the content of reductants or oxidants in the soil. Generally, a drop in Eh is observed within a few days of the waterlogging of a soil. In a coastal saline silty-clay soil, Eh was reduced to 210 mV after four days of submergence (Bandyopadhyay and Bandyopadhyay, 1984). The decrease in Eh mobilized Mn, and the maximal soluble Mn concentration was found after 14 days of submergence in a sandy-loam soil (Sadana and Takkar, 1988). 

Clay loam, clay, silty clay 22 kg Cd/surface ha 11... 

IAp 0-17.5 cm black (10YR 2/1) silty clay loam, weak fine granular structure... 

Experiments involving the release of radioactive carbon dioxide from MSMA-14C treated soils were conducted in a system consisting of two test tubes connected in series. One tube contained 5g of treated soil (at 10 and lOOppm of monosodium methane arsenic acid carbon dioxide while a second tube contained a trapping mixture, 2-methoxyethanol and monoethanolamine (7-10, v/v). Carbon dioxide-free air was passed over the soil and metabolic 14CO was collected in the trapping solution. The soils studied were Sharkey cldy, Hagerstown silty clay loam, Cecil sandy loam, and Dundee silty clay loam. All soils were initially adjusted to field capacity and maintained at 28-30°C the evolved 14CO was sampled periodically. Some properties of these soils are shown in Tabfe 13.1. 

Stiff silty clay, allowable bearing (service load) = 2500 psf 2 ft (120 kPa 0.6 m) Safety Factor = 2 (for conventional loads from soil report)... 

The behaviour of M2D—C3—O—(EO)ra—CH3 (average n = 7.5, 1) on a silt loam and silty clay loam soil has been investigated, with surface tension and spreading ability used as the indicators of degradation/ recovery [16]. The results obtained showed that the inactivation of the surfactant in soil far exceeded any likely loading through... 

Larson et al. [31] performed biodegradation assays of C 13-LAS in surface soils encompassing a range of different soil types (silt loam, loam, sand, sandy loam, silty clay). No soil had been previously exposed to LAS surfactants. The rate and extent of mineralisation were rather independent of the soil type with half-lives in the range of 1.1-4.9 days. The onset of biodegradation was not preceded by a noticeable lag phase... 

An SVE pilot test was conducted at a service station site that had experienced a release of gasoline. Some LNAPL had been removed, but high concentrations of vapor persisted across the site. The site was underlain by silty clay, which overlies weathered and highly fractured shale at a depth of approximately 7 ft. The water table occurs within the upper portion of the shale at a depth of approximately 11 ft. 

The site is underlain by a sequence of unconsolidated, stratified, laterally discontinuous deposits of sand, silty sand, clayey silt, and silty clay of Recent and Upper Pleistocene age. A thin veneer of Recent deposits immediately underlies the eastern portion of the site. These deposits are difficult to distinguish from the underlying Upper Pleistocene deposits, which comprise the lower portion of the Lakewood Formation, due to similarities in lithology. 

Plume No. 1 (areas 1, 3 and 6 in Figure 1) is located in low permeable silty clay deposits to 26m below ground surface (bgs). The groundwater table is 6m bgs and the hydraulic conductivity, k, is 3 x 10 m/s. Concentrations of chlorinated solvents vary from 1 Omg/1 to free phase. 

Two test areas were selected, one in Plume No. 1 in an area underlain by silty clay with a hydraulic conductivity of 3 x 10 m/s and the second in Plume No. 3 in sand and gravel deposits with a hydraulic conductivity of 5x10" m/s. 

COMPACTION TEST CURVE CUW AND SHALE CURVE KH POINT VALUE Clay and silty clay Pelagic clay Terrigenous silty clay Clay with volcanic shard relicts COMPOSITE CURVE... 

From crude oil 0.68 (Grimsby silt loam), 1.00 (Vaudreil sandy loam), 1.54 (Wendover silty clay), 0.53 (Rideau silty clay) (Nathwani and Phillips, 1977)... 

Soil. Lu et al. (1977) studied the degradation of benzo [a] pyrene in a model ecosystem containing Drummer silty clay loam. Samples were incubated at 27.6 °C for 1, 2, and 4 wk before extraction with acetone for TLC analysis. After 4 wk, only 8.05% of benzo [a] pyrene degraded forming one polar compound and two unidentified compounds. The reported half-lives for benzo [a] pyrene in a Kidman sandy loam and McLaurin sandy loam are 309 and 229 d, respectively (Park et al., 1990). 

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