The procedure specified is applicable to all waters having values greater than or equal to 3 mg of oxygen per litre and not exceeding 6 000 mg of oxygen per litre. For greater values the procedure is still applicable, but the errors caused by the dilutions necessary require the results to be interpreted with circumspection. The results obtained are the product of a combination of biochemical and chemical actions. The test may be influenced by the presence of various substances.
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