Research vessel, sampling from

Surface-water samples are usually collected manually in precleaned polyethylene bottles (from a rubber or plastic boat) from the sea, lakes, and rivers. Sample collection is performed in the front of the bow of boats, against the wind. In the sea, or in larger inland lakes, sufficient distance (about 500 m) in an appropriate wind direction has to be kept between the boat and the research vessel to avoid contamination. The collection of surface water samples from the vessel itself is impossible, considering the heavy metal contamination plume surrounding each ship. Surface water samples are usually taken at 0.3-1 m depth, in order to be representive and to avoid interference by the air/water interfacial layer in which organics and consequently bound heavy metals accumulate. Usually, sample volumes between 0.5 and 21 are collected. Substantially larger volumes could not be handled in a sufficiently contamination-free manner in subsequent sample pretreatment steps. 

Reliable deep-water sampling is a special and demanding art. It usually has to be done from the research vessel. Special devices and techniques have been developed to provide reliable samples. 

Most of our understanding of the marine chemistry of trace metals rests on research done since 1970. Prior to this, the accuracy of concentration measurements was limited by lack of instrumental sensitivity and contamination problems. The latter is a consequence of the ubiquitous presence of metal in the hulls of research vessels, paint, hydrowires, sampling bottles, and laboratories. To surmount these problems, ultra-clean sampling and analysis techniques have been developed. New methods such as anodic stripping voltammetry are providing a means by which concentration measurements can be made directly in seawater and pore waters. Most other methods require the laborious isolation of the trace metals from the sample prior to analysis to eliminate interferences caused by the highly concentrated major ions. 

Open Ocean Mercury Determinations. In our initial studies concerned with the marine geochemistry of mercury, we obtained open ocean smrface samples by hand from a small work boat away from any adverse influence of the oceanographic research vessel. The concentrations of mercury in the open-ocean surface waters (western Sargasso Sea) were small (ca. 10 ng/1.) and rather imiformly distributed (26). However, to collect seawater to determine the concentrations of mercury at other depths, we needed an artifact-free sampling procedure. 

Sampling from Oceanographic Research Vessel. In sampling from oceanographic vessels, surface samples were taken with a bucket, as was done from tankers. Samples were taken from the windward side after the vessel had left a station and was imder way at 2-3 knots. 

During expeditions with the German research vessel Polarstern sea water was continuously pumped under clean conditions from the front of the ship bow at a depth of 10 m into a laboratory, where samples were collected into precleaned PE bottles. Subsequently, the samples were filtered using a 0.45 pm pore sized filter and then analyzed as soon as possible. For the analysis of VHOCs a 10 1 precleaned steel bucket was also used in some cases. Only ultra pure chemicals were used for the pretreatment of samples. 

Sediment samples were collected using a grab sampler (which samples approximately the top 10 cm) aboard Old Dominion University s research vessels, ODU-1 and Linwood Hoi Con. The sample locations are shown In Figure 1. The samples were stored frozen In clean, solvent-washed jars until analyzed. Creosoted wood samples were collected from areas adjacent to the Elizabeth River (Figure 1). Three samples of refined creosote and one sample of coal tar were also analyzed. Creosote samples from Atlantic Wood Industries, the remaining operative creosotlng facility on the Elizabeth River, were not available. The woodstove soot sample was obtained from a domestic woodstove in which predominantly hardwoods were burned. 

In the course of such investigations, workers in this area learned to what extremes they had to go to ensure that their sampHng would not be contaminated by material emanating from the research vessel itself. Special sampling platforms had to be built [ 129], and extreme precautions used in sample taking and handling [130]. This last reference is to work which is certainly a milestone in the field I do not expect to see it improved upon unless or until someone thinks of an exceedingly clever way to sample this material. 

Collection of undisturbed discrete surface seawater samples from research vessels is not possible. To leave the contaminated water plume of the main vessel and to approach closer to the sea surface, suitable small tenders have to be used. Sampling is performed from the lee-side of the tender, >200m up-wind from the ship in an area not previously passed by any vessel. During sampling, the tender may be moved slowly at right angles to the direction of the prevailing surface currents. 

For recording vertical profiles of basic hydrochemical pararmeters in the sea (such as salinity, pH, oxygen and nutrient concentrations), water samples from different depths should be taken quasi-synchronously. On a number of ships, the famous Nansen bottle (Fig. 1-4) introduced more than 70 years ago (Knudsen, 1923,1929) is still part of standard oceanographic equipment. Even on modem research vessels it is often carried for comparison purposes and as a back-up. 

Not infrequently, even research vessels are sources of petroleum which rapidly forms a plume around the ship when on station. Therefore, samples for the determination of petroleum-derived hydrocarbons in seawater should be taken immediately after the ship has come to a stop. If this is not possible, one might consider rowing a rubber dinghy some distance upwind from the ship to take the samples (do not use an outboard engine). 

The procedure of using small boats provided with sample bottles attached to a telescopic device is recommended as a means to minimize contamination from the research vessel during coastal water sampling. Of the wires used to suspend samplers, plastic-coated steel gave negligible, and Kevlar and stainless steel only slight, contamination for some metals [7]. 

There are three main types of contamination to be aware of when collecting samples. The first are airborne and waterborne contaminants such as tobacco smoke, dust, exhaust fumes, cleaning and lubricating solutions as well as hydrocarbons from a research vessel or other vessels in the water. This category of contaminant can normally be avoided by paying careful attention to the sampling site and sampling upwind (or on the lee side of a... 

Scale-Up Fermenters ranging from about two to over 100 hters (0.07-3.5 fP) have been used for research and development, but the smaller sizes provide too httle volume for sampling and are difficult to replicate, whue large vessels are expensive and use too much medium. Autoclavable small fermenters that are placed in a water bath for temperature control are less expensive than vessels with jackets or coils, but much labor is required for handling them. Pressure vessels that... 

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