Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Sample types sediment

Mineral exploration, the search for economic ore deposits, requires somewhat different reference samples than those used in ore valuation. Soil or sediment and water samples are frequently used in the search when mineralized areas of abundant outcrop or those covered only by thin locally derived overburden are being evaluated. In such cases, it is virtually impossible not to detect the mineralization from an analysis of ore elements in these types of samples. Later, as the mineral deposits closest to the surface were exploited and then played out, new deposits occurred at progressively greater depths, and these sample types were less and less effective as markers in the search (Hoffman 1989). [Pg.226]

This table highlights some, but not all, of the available methods that have sufficiently low detection limits to render them applicable to even the lowest concentrations of organometallic compounds encountered in various types of environmental samples. Thus, Table 13.13 is a useful starting point for the selection for any particular type of any organometallic compound and sample type of an appropriate analytical method that will cover the range of concentrations likely to be encountered in the sample including very low concentrations. The situation will depend on the type of sample, viz. sediments, soils or sludges. [Pg.428]

The CONSULTATION function is run by using the mouse to select the text "CONSULTATION" from the computer screen. The first question of the dialogue, "Please enter the class of your sample of interest", appears on the screen. The pop-up menu lists the sample types to chose from. The investigator then uses the mouse to select the appropriate response from the pop-up menu. This question and answer procedure continues until SpinPro has enough information, typically 10 to 15 questions, from which to infer all of the relevant parameters. The dialogue is directed by SpinPro in response to answers to previous questions. Thus, if the sample is a protein, SpinPro requests the sedimentation coefficient if the sample is a nucleic acid, SpinPro requests the type of nucleic acid. At the conclusion of the dialogue, the reports are written to the disk. Using the pop-up menu, the reports can be read or saved. [Pg.299]

Several overall conclusions can be drawn based on the statistical evaluation of the data submitted by the participants of the DR CALUX intra-and interlaboratory validation study. First, differences in expertise between the laboratories are apparent based on the results for the calibration curves (both for the curves as provided by the coordinator and for the curves that were prepared by the participants) and on the differences in individual measurement variability. Second, the average results, over all participants, are very close to the true concentration, expressed in DR CALUX 2,3,7,8-TCDD TEQs for the analytical samples. Furthermore, the interlaboratory variation for the different sample types can be regarded as estimates for the method variability. The analytical method variability is estimated to be 10.5% for analytical samples and 22.0% for sediment extracts. Finally, responses appear dependent on the dilution of the final solution to be measured. This is hypothesized to be due to differences in dose-effect curves for different dioxin responsive element-active substances. For 2,3,7,8-TCDD, this effect is not observed. Overall, based on bioassay characteristics presented here and harmonized quality criteria published elsewhere (Behnisch et al., 2001a), the DR CALUX bioassay is regarded as an accurate and reliable tool for intensive monitoring of coastal sediments. [Pg.52]

Protocols for preparing six environmental sample types prior to the Ames Salmonella assay were proposed at a recent panel discussion sponsored by the U.S. Environmental Protection Agency (USEPA) and the U.S. Army. Air particles, soil-sediment, and solid waste are extracted with dichloromethane, concentrated, and solvent exchanged into dimethyl sulfoxide (DMSO). Organics in water and waste water are absorbed onto XAD columns, then eluted with hexane-acetone, solvent reduced, and exchanged into DM SO. Nonaqueous liquids are assayed directly and as concentrates before they are solvent exchanged to DMSO. If bacterial toxicity or lack of dose response is observed in the Ames assay of extracts, the extracts are fractionated prior to solvent exchange. These are interim methods and have not been subjected to policy review of the USEPA or the U.S. Army. [Pg.25]

Based on a full suite of sample types including soil, stream sediment, surface water, groundwater and offshore marine and estuarine sediment in the coastal zone. [Pg.8]

Upper horizon of overbank sediments, which is one of the mandatory sample types of the Global Reference Network, will not be sampled during this FOREGS sampling project. Flowever, each country can choose to collect upper horizon samples of overbank sediments as well as deep layers of floodplain sediments and overbank sediments, which are optional materials in the Global Reference Network. No regional analytical services can be provided for these materials. [Pg.31]

Studies on water pollution by POPs can be categorized according to the water bodies studied, such as rivers, seas, and oceans harbors, lakes, and reservoirs and groundwater. They can also be categorized according to sample types, e.g., surface water, deepwater, surface micro-layer, and pore water in sediments. In China, extensive monitoring of pesticide POPs has been carried out in rivers, bays and harbors, and lakes. The results show that the spatial differences of pesticide concentrations in water are larger than that in air, but smaller than that in soil. [Pg.180]

Investigations of lead speciation in various environmental samples have relied upon gas and liquid chromatographic separations coupled to mass spectrometric and atomic absorption spectrometric detectors. The combination of atomic absorption spectrometry with gas chromatography (GC-AAS) has proved to be the most widely applied technique. Sample types have included air, surface water, air particulates, sediments, grass, and clinical materials such as blood. A review of speciation analyses of organolead compounds by GC-AAS, with emphasis on environmental materials, was published (Lobinski et al., 1994). [Pg.422]

Sampler i unpacks all the sampling equipment. Sampler 2 labels the water sample bottles (and the sediment and panned concentrate bags). Four botdes are used for various analytical methods. The pre-allocated site number (taken from the field card) is written on the sample containers, using the black permanent ink marker. The site number becomes the sample number by including a sample type code as... [Pg.76]

Sample type Date Bottom sediment layer, radionulclide ... [Pg.157]

Unlike vanadium, REE/Fe ratios recorded in even the most recent metalliferous sediments are much higher than those in suspended hydrothermal plume particles (German et al., 1990, 1997 Sherrell et al., 1999). Further, hydrothermal sediments REE/Fe ratios increase systematically with distance away from the paleo-ridge crest (Ruhlin and Owen, 1986 Olivarez and Owen, 1989). This indicates that the REE may continue to be taken up from seawater, at and near the sediment-water interface, long after the particles settle from the plume to the seabed. Because increased uptake of dissolved REE from seawater should also be accompanied by continuing fractionation across the REE series (e.g., Rudnicki and Elderfield, 1993) reconstruction of deep-water REE patterns from preserved metalliferous sediment records remain problematic. Much more tractable, however, is the exploitation of these same sample types for isotopic reconstructions. [Pg.3066]

Various sample t es (soil, sediment, biota) from different locations were analysed. In most cases commercially available reference materials were used due to their well-documented sampling conditions and wide variety of sampling sites. Furthermore, bioindicators, especially moss samples were measured. These samples were from higher-contaminated (collected by the Hungarian Nuclear Society in Chernobyl and Pripjaty) and less-contaminated (Hungary and South-France) sites. The sample types, sampling locations and dates are summarized in Table 1. [Pg.70]

Any measurement on a real-world sample is always a combination of the free and bound gas sample types. This is because the process of taking the gas sample generally requires that the sediment or rock system is disturbed by some mechanical means which creates the mixing of these sample types. Because of this unavoidable interaction, we have recognised the need to consider an intermediate sample-collection technique that measures the more loosely-bound gases liberated into a container containing the core sample. [Pg.151]

The gradient approach requires a great deal to be known about the landscape of the watershed, airshed, or other division of the area under consideration. Ideally, it is nice to have data on land use, geology, the hydrology, soil types, sediment composition, types of contaminants, the history of disturbance, and other information available when deciding a sampling plan. These data may not be available, and this uncertainty should be reported. [Pg.348]

The composition of the chlorobiphenyl mixtures present In the surface sediment, particulate matter In the water column, filtrate from water column samples, and mussels reflect a combination of Aroclor 1242 and 1254 mixtures of chlorobiphenyls although there are distinct differences In each sample type. The chlorobiphenyl composition of water column samples (gas chromatograms not shown) resembles that of the mussels and surface sediments, although further measurements of a larger set of samples may reveal small but significant differences In composition. [Pg.179]

Sample type total sediments Sample prep. Open digestion with HN03, and HF. [Pg.222]


See other pages where Sample types sediment is mentioned: [Pg.944]    [Pg.156]    [Pg.302]    [Pg.422]    [Pg.60]    [Pg.438]    [Pg.196]    [Pg.98]    [Pg.45]    [Pg.663]    [Pg.199]    [Pg.528]    [Pg.199]    [Pg.270]    [Pg.525]    [Pg.32]    [Pg.115]    [Pg.7]    [Pg.15]    [Pg.229]    [Pg.278]    [Pg.77]    [Pg.81]    [Pg.1220]    [Pg.1257]    [Pg.1321]    [Pg.103]    [Pg.163]    [Pg.216]    [Pg.427]    [Pg.223]    [Pg.471]    [Pg.125]   
See also in sourсe #XX -- [ Pg.90 ]




SEARCH



Sample types

Sampling types

Sediment types

Sediments, sampling

© 2024 chempedia.info