Sediments sample handling

Generally, due to the instability of polluted sediments, sample handling and storage prior to the fractionation of TEs are somewhat problematic. In particular. 

Similar to most Hg sampling methods, sampling sediments and soils require care in avoiding contamination artifacts due to improper sample handling. However, because Hg concentratiorrs are much higher in soUd matrices than in water, if corrrmonly accepted trace-metal protocols are used, substantial contamination artifacts should be exceedingly rare. Also, because sediment Hg concentration profiles... 

METHODS FOR THE SAMPLE HANDLING OF NON-IONIC SURFACTANTS IN SLUDGES AND SEDIMENTS... 

Methods for the sample handling of non-ionic surfactants in sludges and sediments... 

Since the beginning of the 1980s, the presence of surfactants in solid matrices has slowly received more attention. The publication by Giger and coworkers in 1984 [2] on the anaerobic formation in sewage sludge of nonylphenol (NP) out of alkylphenol ethoxylates (APEOs) particularly stressed the importance of this environmental compartment. However, environmental data of surfactants in sediments and sludges remains scarcer than data on aqueous concentrations, undoubtedly because sediment samples are more difficult to handle. 

In this chapter, all four types of sediment and sludge sample handling techniques for non-ionic surfactants will be discussed and compared. Most of the studies published on non-ionics focus on APEOs and their degradation products, viz. the alkylphenols, but some extraction methods for alcohol ethoxylates (AEOs) and coconut diethanol amides will also be discussed. 

The interlaboratory results obtained from the analysis of defined standard solutions, but also from the analysis of sediment extracts prepared either by the coordinator of the study or by the participants themselves, also provide a measure of the variation between laboratories. The results show that the interlaboratory reproducibility ranges from 6.5% for the defined dioxin sample to 27.9% for the sediment sample extracted by the participants themselves. As was mentioned before, the reproducibility for this last sample is relatively high and most presumably due to the introduction of extra handlings (extraction and cleanup) to the total procedure. In addition, the fact that not all the participants had prior experience with the extraction protocol to be used could have added to the increase in variability of the process. Furthermore, the dilution factor was not dictated. This also introduces a certain degree of variation. For the reproducibility of the DR CALUX bioassay itself and not caused by differences in operating extraction conditions, the maximum variation between laboratories was observed to be 18.0%. The results for the sediment extract samples can also be used to estimate the method variability for extracts, that is, based on samples of unknown composition. Again, given the intra-as well as the interlaboratory variations observed in this study, it appears justified to conclude that the standard deviation of the means provides a reasonable estimate of the method variability, based on the overall aver-... 

Glove box. For use in preparing standards from neat materials and in handling soil/sediment samples containing fine particulates that may pose a risk of exposure. 

In solid particulate systems, direct observation is justifiably the last word. In emulsions where creaming, sedimentation, and coalescence can change the nature of the sample, microscopic observation has unique sample handling problems. If these special sampling problems are addressed, then microscopy can indeed provide the benchmark for the physical characterization of the dispersed phase in emulsion systems. 

Detailed information on procedures for the collection, handling and preservation of aqueous and sediment samples is given in a series of ASTM (1994a,b) and ISO (1990, 1991, 1992a,b, 1994, 1995, 1998a,b, 1999, 2000) documents. General issues for the collection, storage and preparation of environmental samples for bioassays that need to be considered are summarised below ... 

ISO (1999) Water Quality - Sampling - Part 15 Guidance on Preservation and Handling of Sludge and Sediment Samples, ISO 5667-15. International Organization for Standardization, Paris. 

International Standards Organisation (1999) Water quality - sampling, part 15 guidance on preservation and handling of sludge and sediment samples, ISO 5667-15 1999. 

The further handling of samples involves grinding using a simple mortar or an analytical mill. We propose the following sample handling and preparation scheme for NIR-analysis of sediment samples ... 

This sample handling and preparation scheme has been subjected to various tests, and proved to result in reproducible spectral signals (see e.g., Dabakk et al, 1999). As suggested by Malley Williams (1997), the sample could be sieved prior to NIR analysis in case the sediment contains coarse grained particles (>2 mm). Apart from the possible effects of grinding, the sample preparation and the subsequent NIR-analysis is non-destructive. This means that the sample can be used for further physical, chemical or biological analyses using conventional analytical techniques. 

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