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Corers, sediment

Sediments from the bottom of streams, rivers, lakes, estuaries, and oceans are collected with a bottom grab sampler or with a corer. Grab samplers are equipped with a pair of jaws that close when they contact the sediment, scooping up sediment in the process (Figure 7.5). Their principal advantages are ease of use and the ability to collect a large sample. [Pg.197]

Schematic diagram of a piston corer in operation. The weight of the corer is sufficient to cause its penetration into the sediment, while the upward motion of the piston allows water pressure to help force the sediment column into the barrel of the corer. Schematic diagram of a piston corer in operation. The weight of the corer is sufficient to cause its penetration into the sediment, while the upward motion of the piston allows water pressure to help force the sediment column into the barrel of the corer.
The devices used for sampling of solid samples (sludge, sediment, and soil) are usually grab samplers or corers. Box corers or multicorers can be employed if more detailed information on the spatial distribution of the analytes is needed. The samples are stored in the dark at 4 °C or more commonly at -20 °C, preferably in glass containers [53]. Very often, solid samples are also dried or lyophilized prior to storage. [Pg.19]

After collection, samples were divided into 5-cm sections or into sections determined by changes in sample matrix. Only sediment from the interior of the core (not in contact with the corer) was used to avoid possible contamination from the polycarbonate and from sediment fines forced along the wall of the tube. Sectioned samples were stored in solvent-rinsed bottles at 4 °C until analyzed. Some samples used in this study were collected from reaches of the submerged riverbed (where PCBs were deposited before the reservoir was filled). Sample locations (Figure 1) were determined in relation to buoys placed and maintained by the U.S. Army Corps of Engineers. Samples used in this study were limited to those found to be contaminated with at least 1 xg/g of total PCB to minimize quantification error during weight-percent calculations. [Pg.570]

Hollow tubes or casings that are used to collect soil or sediment samples. Small soil corers are normally pushed into the soil or sediment by hand-held tools. See also Sediment core sample. (PIANC, 1997). Volume 2(9). [Pg.386]

Sediment sample collected with a corer. The advantage of corers is that they preserve the vertical profile of the chemical constituents of the sediment. This allows for sediments to be sub-sampled to specific depths. Volume 2(9). [Pg.404]

FIGURE 1.9 Collection of sediment samples from shallow water with a manual corer. [Pg.12]

The northern portion of Chesapeake Bay was studied. This upper section of the bay can be classified as a classic salt-wedge type estuary (15). The humic materials used in this study were extracted from several cores of sediments. Two one-meter cores gravity corer. The cores of sediments were then divided into sections and squeezed under nitrogen to remove most of the interstitial water. The squeezed sediments were then dried, weighed and washed with distilled water. The sediments were then washed with 0.5N KCl to remove iron hydroxides, carbonates and exchangeable cations from the clays. Some of the fulvic acids are lost in this acid wash procedure. The humic materials were then extracted from the remaining solids by a O.IN NaOH solution. [Pg.134]

The team of Ahn et al. used a PVC corer to sample habitat sediment relevant to the clam Laternula elliptica from the Collins Harbour (Maxwell Bay, King George Island) at a depth of 30 cm (42). Samples were extracted with high-purity HNO3 after oven-drying. Cadmium, Co, Cr, Fe and Zn were measured by F-AAS and ETA-AAS in an attempt to clarify the mechanism of bioaccumulation of the metals in the organism. [Pg.19]

Surface sediments are generally collected by a stainless steel grab, while a box-corer system is used if depth profile is required. A stainless steel shovel, pre-rinsed with acetone for organic residue analysis, is used to collect soil samples. Also in this case, potential contamination by airplane exhaust on surface soil can be minimized by removing the top 2-3 cm of soil and by sampling upwind of the landing site. Samples are generally stored below 0"C in stainless steel containers. [Pg.241]

Sediment cores were taken with a gravity corer. They were sliced with 0.5-cm resolution and processed the same way as sediment-trap material. One of the cores (code SE-8802) was dated by Wieland et al. (41), who used the 137Cs record from bomb fallout and the Chernobyl accident. The authors determined the sediment accumulation rate at this site to be 1.84 g/m2 per day. This value agrees with the average sedimentation rate of 2.17 g/m2 per day gleaned from the sediment-trap record of the years 1984-1991 at a depth of 81 m. [Pg.115]

The sediments were obtained using short gravity coring devices (Niemistd-corer, 1988 Multi- corer, 2005). From each of the cores, the uppermost slices (1988 0-3 cm 2005 0-2 cm) were separated for analysis, freeze dried, and homogenized. In total, 308 (1988) and 56 (2005) surface samples were investigated. [Pg.424]

Sampling. Sediment samples from the coast of Peru were collected during Cruise 23-06 of the R/V Robert Conrad, June - July, 1982. Sampling locations are indicated In Figure 2. A specially designed box corer (22) was used In order to obtain undisturbed surface sediments (<50 cm depth). Subcores were taken on board, sectioned over 2 cm Intervals, and each subsection immediately frozen. The frozen samples were packaged In dry Ice and shipped to the FSU chemistry department, where they were stored in a -10 C freezer until analyzed. [Pg.161]

Samples origin. Wastewater was collected once a month (March-July, 1987) in the influent of the Barcelona treatment plant, as a manual composite. Seawater was collected at 1.5 km offshore in a transect parallel to the coast of Barcelona from a sailing boat in order to prevent sample contamination Sediments were collected using a box corer at 4 Km offshore at the vicinity of the Barcelona city outfall. [Pg.16]

Deep-sea benthic foraminifera live on, and within, the sediment down to a depth of 10 cm below the seafloor (Corliss 1985 Gooday 1986 Mackensen Douglas 1989). After two decades of intensive research and collecting high-quality samples with the aid of multiple corers, there is no doubt that... [Pg.122]

Coring is done by gently pushing the bottomless corer into the sediment to a depth of 10-22 cm in the case of x-ray and chem boxes, or 10-15 cm for flux boxes. The vent holes in the top are then sealed with rubber... [Pg.250]

After interstitial water had drained from the cores approximately 50 g of wet surface sediment (top 1-3 cm) was placed in a preextracted cellulose thimble for soxhlet extraction. Care was taken not to use any sediment that had contacted the corer. All possible precautions were taken against contamination during sampling and handling of the samples. [Pg.275]

An earlier study (11) of alkanes, cycloalkanes, and phenanthrenes in another sediment core from this location showed an interesting trend of decreasing concentrations between the upper 2 cm and 54-58 cm, which pointed towards fossil fuel combustion as the principal source of hydrocarbons in these surface sediments. The core was collected in August 1975 with a 21-cm-diame-ter, 1-m-long sphincter corer (14). Three sections of the core were used for this study Sample 4, the top 4 cm Sample 5, 20-24 cm and Sample 6, 38-42 cm. There was no sulfide present in the top 8 cm. An oxic, bioturbation zone of about 4 cm is indicated by the 210Pb depth profile and benthic ecology studies (12,15). [Pg.300]

Whatever device is used to collect sediment, the device used and its material of construction should be such that contamination of samples is avoided. For example, if corers are used, they should be appropriately precleaned and sealed before use, and sediment grabs used to take a series of samples should be cleaned of any adhering sediment between each sample. [Pg.13]


See other pages where Corers, sediment is mentioned: [Pg.115]    [Pg.1083]    [Pg.115]    [Pg.1083]    [Pg.197]    [Pg.228]    [Pg.407]    [Pg.18]    [Pg.570]    [Pg.11]    [Pg.16]    [Pg.127]    [Pg.135]    [Pg.52]    [Pg.21]    [Pg.260]    [Pg.411]    [Pg.413]    [Pg.521]    [Pg.35]    [Pg.36]    [Pg.42]    [Pg.122]    [Pg.160]    [Pg.251]    [Pg.13]    [Pg.13]    [Pg.27]    [Pg.688]    [Pg.83]    [Pg.90]    [Pg.90]   
See also in sourсe #XX -- [ Pg.215 , Pg.216 , Pg.217 , Pg.218 ]




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