Local investigations see also

It is recommended that appropriate forms be issued depending on the type of individual analysis, as guidance not only for the laboratory but also for the sampler. 

A summary of the local investigations generally to be conducted is given below. In the case of individual elements, fixation of the constituent to be determined is necessary and appropriate reference is made to the section of investigation. 

Temperature of the water (to 0.1 C with a calibrated mercury thermometer) 

Measure electrical conductivity electrometrically on site at the same time as temperature 

Measure redox potential electrometrically excluding atmospheric oxygen and secondary redox processes 

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