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Passive sampling offers several advantages over conventional sampling. The sampler is in place for a longer period of time (often days or weeks), accumulating the analytes. The result is an average of the concentration during this time, which eliminates the risk of non-detection of, for example, occasional peaks in emitted pollutants.
PS Metal is used to sample metals in situ in water, soil and sediment. The simple plastic sampler contains a filter, a hydrogel, and an ion exchange resin. Metal ions in water diffuse through the filter and the gel, and finally accumulate in the ion exchange resin. The longer the sampling time, the larger the amounts of ions accumulated. In uncontaminated water, the equipment can be left in place for several months. The ions are then eluted from the resin with acid, and can be deteremined by ICP-AES or ICP-MS. If the water temperature and the exposure time are known, the concentration of each metal in the water can easily be calculated.
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The sampler for sediment is in the shape of a narrow wedge that is pushed into the sediment. The final result is a concentration profile with high spatial resolution.
Metal toxicity is strongly influenced by the complexation reactions that take place in natural aquatic systems. In many cases, the concentration of trace metal that is available for aquatic organisms differs from both the total concentration and from that of dissolved metal. In sampling with PS Metal, particle-bound and strongly complexed metal will be excluded in a manner which corresponds to their non-availability for biota. Consequently, PS Metal is not directly comparable to either total or dissolved concentrations in an ordinary water sample. Quantitative results can be calculated for all elements that are included in our PS Metal analytical packages.
ALS uses passsive samplers for metals based on DGT™ technology.
For more information on passive sampling, please contact Elsa Peinerud,
phone +46 8 5277 5205 or Ingalill Rosén, +46 8 5277 5220.
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