Manometric Respirometry (OECD 301F)
Freshwater Manometric Respirometry Test (Oxitop) - Ready Biodegradability
This freshwater ready biodegradibility test uses Oxitop apparatus and is part of the OECD 301 series of methods.
A measured volume of inoculated mineral medium, containing a known concentration of the test substance (100 mg/l giving at least 50-100mg ThOD/l) as the source of organic carbon, is stirred in a closed flask at a constant temperature for up to 28 days. During the course of the test oxygen is consumed and carbon dioxide evolved. The carbon dioxide is absorbed in sodium hydroxide and the drop in pressure in the test vessels therefore determines the oxygen consumption. The caps of the test vessels contain a pressure transducer and microprocessor to measure and calculate BOD.
The amount of oxygen taken up by the microbial population during biodegradation of the test substance is expressed as a percentage of ThOD or, less satisfactorily, COD.