Sample Preparation

• Contamination must be avoided in sample collection, preparation and storage by appropriate choice of tools, equipment and containers.

Stream Sediment 

• Depending on field sample site conditions wet or dry sieving of stream sediment may be employed; if sieving is not possible in the field, then the samples are sieved in the laboratory after drying at either room temperature or in thermostatically controlled ovens at a temperature of <40^oC.

• Upper limit of drainage sediment grain-size fraction analysed should be in the range of 0.10 to 0.18 mm; if this fraction is scarce, then a coarser fraction should be used.

• A minimum of 100 g of the sieved fraction is required for analysis;

• Sample material not required for immediate analysis should be archived for future use in contaminant-free permanent containers;

• Systematic labelling and documentation is essential.

 Soil and Floodplain/Overbank Sediment 

• Samples are first dried in the laboratory at either room temperature or in thermostatically controlled ovens at a temperature of <40^oC;

• A minimum of 100 g of the sieved fraction is required for analysis;

• Sample material not required for immediate analysis should be archived for future use, in contaminant-free permanent containers;

• Systematic labelling and documentation is essential.

Note:

In all cases, the samples should be sieved through a metal free polyethylene sieving cloth mounted on a polyethylene or wooden frame.
Grinding is recommended and should be carried out using high-alumina ceramic or agate equipment.

The sample preparation room must be clean and free of dust and the equipment cleaned thoroughly between each sample.