Soil and sediment

Wang and Fang [3] deteimined arsenic in soUs by Fl-HGAAS following digestion of the sample with a mixture of nitric, perchloric and hydrofluoric acids and reduction of arsenic(V) to (III) by KI. Recoveries were satisfactory (cf. Sec. 8.8.4). 

Sun et al.f57] determined total nitrogen in soil samples by spectrophotometry with an on-line gas diffusion system after a Kjeldahl digestion (for details cf. Sec 8.8.1.). 

The same method used by Wang and Fang [42] for the determination of selenium in biological materials (cf. Sec. 8.8.4) was applied to the determination of selenium in soil digests with good recoveries in the analysis of spiked samples. 

In contrast with water analysis, where sample preparation is a relatively easy task, the analysis of solid matrices, such as soils and sediments, requires more steps before the measurements. One can save time and enhance the efficiency of extraction or the completeness of digestion. Table 2.8 summarizes some of the recent publications of MAE applied to soil and sediment analysis. 

Yang et al. studied MAE of polychlorinated biphenyls (PCBs) and polychlorinated dibenzodioxins (PCDDs) from fly ash and sea sediments. The effect of the addition of water to the extracting solvent (solvation) and sample matrices (wetting) on the variation of recoveries was studied. The results indicate that MAE, using 1% to 2% of solvation or 10% to 20% of wetting in 90 10 (v/v) of toluene-lPA mixtures, was the most effective treatment in isolating PCBs and PCDDs from the samples. Multi-layer column chromatography on neutral and acidic silica gel with 

Although MAE is claimed as the best extraction technique in most published works, Soxhlet extraction was claimed as more precise for the determination of OCPs in sediments. Additionally, higher recoveries were reported by using Soxhlet extraction. 

Ghassempour et al. published an interesting work comparing MAE and ultrasonic extraction (USE) for the extraction of diazinon from soil and the stems of rice plants. After optimizing the conditions, better results (98% recovery) were obtained by MAE with hexane as solvent. The USE method gave 91% recovery with the same solvent. The reduced extraction time, minimal amount of solvent, the fact that the soil and steam moisture did not influence MAE when a solvent such as acetone is used, and higher recoveries, made MAE the method of choice in this study. 

On the contrary, Contat-Rodrigo et al. proposed USE as a better method in terms of reproducibility and extraction efficiency. They studied the extraction of degradation products from degradable polyolefin blends aged in soil. Higher amounts of certain products (e.g., carboxylic acids) were extracted by USE than by MAE. 

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Typical examples of solid samples include large particulates, such as those found in ores smaller particulates, such as soils and sediments tablets, pellets, and capsules used in dispensing pharmaceutical products and animal feeds sheet materials, such as polymers and rolled metals and tissue samples from biological specimens. 

The EPA Contract Laboratory Program (CLP) has responsibility for managing the analysis programs required under the U.S. Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). The approved analytical methods are designed to analyze water, soil, and sediment from potentially hazardous waste sites to determine the presence or absence of certain environmentally harmful organic compounds. The methods described here all require the use of GC/MS. 

Aquatic field dissipation studies soil and sediment... 

This proeedure has been applied to thousands soil and sediment samples and hundreds biologieal and water samples taken in the exelusive zone of Chernobyl NPP and different regions of Ukraine. The methods developments ai e deseribed. 

X-RAY FLUORESCENCE DETERMINATION OE MINOR AND TRACE ELEMENTS IN VARIOUS TYPES OE ROCKS, SOILS AND SEDIMENTS BY PIONEER SPECTROMETER... 

The behavior of elements (toxicity, bioavailability, and distribution) in the environment depends strongly on their chemical forms and type of binding and cannot be reliably predicted on the basis of the total concentration. In order to assess the mobility and reactivity of heavy metal (HM) species in solid samples (soils and sediments), batch sequential extraction procedures are used. HM are fractionated into operationally defined forms under the action of selective leaching reagents. 

Recently it has been shown that rotating coiled columns (RCC) can be successfully applied to the dynamic (flow-through) fractionation of HM in soils and sediments [1]. Since the flow rate of the extracting reagents in the RCC equipment is very similar to the sampling rate that is used in the pneumatic nebulization in inductively coupled plasma atomic emission spectrometer (ICP-AES), on-line coupling of these devices without any additional system seems to be possible. 

These bacteria are anaerobic. They may survive but not actively grow when exposed to aerobic conditions. They occur in most natural waters including fresh, brackish, and sea water. Most soils and sediments contain sulfate reducers. Sulfate or sulfite must be present for active growth. The bacteria may tolerate temperatures as high as about 176°F (80°C) and a pH from about 5 to 9. 

Remediation activities at American Thermostat included the excavation and thermal treatment of over 13,000 cubic yards of soil and sediments contaminated primarily with perchloroethylene, trichloroethylene, and solvents. The soil was excavated and treated using a thermal treatment unit called the low-temperature enhanced volatilization facility (LTEVF). The performance test for the site s thermal unit had just been completed at the time of the inspection, so there was limited activity. 

Nriagu, J. O. (1976). Phosphate-clay mineral relations in soils and sediments. Can.. Earth Sci. 13,717-736. 

The categorization as inherently biodegradable together with the values and other physical properties enabled estimates of biodegradation half-lives in water, soil, and sediment to be made by BUSES. Those for soil and sediment were then reduced to be more consistent with the results of Terytze et al. (2000), as shown in Table 8. 

Table 8 Biodegradation half-lives in fresh water, soils, and sediments.

In soil and sediments, methyl parathion adsorbs to soil and is expected to display moderate mobility (EPA 1980c). The major degradation process of methyl parathion in soil is biodegradation by microbes (Badway and El-Dib 1984). Degradation by hydrolysis has been observed to occur at higher temperatures... 

In soils and sediments, microbial degradation and hydrolysis are important degradation processes. 

In random samples of soil taken from five Alabama counties, only 3 of 46 soil samples contained methyl parathion. The concentration in these samples was <0.1 ppm (Albright et al. 1974). Aspartofthe National Soils Monitoring Program, soil and crop samples from 37 states were analyzed for methyl parathion during 1972. Methyl parathion was detected in only 1 soil sample, at a concentration of <0.1 ppm and taken from South Dakota, out of 1,246 total samples taken from the 37 states (Carey et al. 1979). In soil and sediment samples collected from a watershed area in Mississippi, methyl parathion was not detected in the soil samples. In three wetland sediment cores, however, measurable concentrations of methyl parathion were detected during application season (Cooper 1991). 

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