Suomen ympäristökeskus

This document specifies techniques for preparing poorly water-soluble organic compounds (i.e. liquid and solid substances) with a solubility in water of less than approximately 100 mg.l-1 and introducing them into test vessels for a subsequent biodegradability test in an aqueous medium using standard methods. The subsequent tests on biodegradability are primarily methods using the analysis of the released carbon dioxide described in ISO 9439 and the determination of the oxygen described in ISO 9408 and following the usual precautions for ISO 10707. Thus, one can notice that the methods measuring the removal of DOC are not appropriate. This document does not specify the biodegradation test methods; it is restricted to describing the techniques for introducing the test compounds into the test medium and to keep them in a dispersed state (Reference[4]). These techniques are implemented while observing the experimental conditions described in the standardized methods for evaluating biodegradability. It should be noted that volatile compounds may not be tested by the carbon dioxide method specified in ISO 9439. Users should be aware that some of the preparation methods described in this document might not be accepted by regulators for concluding on the ready biodegradability of tested compounds.

This document specifies a method for the determination of free chlorine and total chlorine in water, readily applicable to lab- and field-testing; it is based on measurement of the absorption the red DPD colour complex in a photometer or the colour intensity by visual comparison of the colour with a scale of standards that is regularly calibrated. Seawater and waters containing bromides and iodides comprise a group for which special procedures are required. This method is in practice applicable to concentrations, in terms of chlorine (Cl2), from e.g. 0,000 4 mmol/l to 0,07 mmol/l (e.g. 0,03 mg/l to 5 mg/l) total chlorine. For higher concentrations, the test portion must be diluted. Commonly, the method is applied as a field method with mobile photometers and commercially available ready-for-use reagents (liquid reagents, powders and pellets). It is essential that those reagents fully comply with minimum requirements and contain the essential reagents and a buffer system suitable to adjust the measurement solution to a pH range of 6,2 to 6,5. If there is doubt that water samples have uncommon pH values and/or buffer capacities the user has to check and if necessary to adjust the sample pH to the required range. The pH of the sample shall be within the range of pH 4 and 8. Adjust, if necessary, with sodium hydroxide solution or sulfuric acid before the test. A procedure for the differentiation of combined chlorine of the monochloramine type, combined chlorine of the dichloramine type and combined chlorine in the form of nitrogen trichloride is presented in Annex A. In Annex C, a procedure is presented for the determination of free and total chlorine in drinking and other low polluted waters, for disposable planar reagent-filled cuvettes using a mesofluidic channel pump/colorimeter.