Sample pre-treatment issues

The sample preparation protocol is an integral part of the analysis result. This important criterion is often overlooked by users of the analysis results. For example, there are three common soil preparation protocols  

Protocol 1 All results relate to the air-dried part of the soil that will pass through a 2 mm-mesh sieve after gentle manual crushing to break up larger soil particles. All stones larger than 2 mm are assumed to be inert and rejected prior to analysis of the ground (less than 200 pm) portion. Results relate to the sub-sample analysed. 

Protocol 3 As protocol 2 except all results reported in relation to as received sample, not the sub-sample analysed. 

The CLEA cadmium soil guideline value (SGV) for residential land use (without plant uptake) of 30 mg/kg is the criterion being used to assess the samples. 

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