Biodegradation is the biochemical process of the decomposition and mineralization of organic compounds that occurs, when organisms like bacteria, fungi, protozoa and other organisms use an organic substance as a source of carbon. It is a key phenomenon among environmental processes with the aim to assess a persistence of organic substances.
Through this biologically natural process, hazardous toxic contaminants are transformed into less toxic or non-toxic substances, resp. a change appears from complex substances into simpler ones before returning to the environment. For example, the activated sludges are used to treat sewage flows in a waste water treatment plant to biotransform the organic compounds up to get their complete mineralization.
The process of biodegradation can be modelled and conducted very effectively in the laboratory conditions for many organic substances using validated and approved OECD methods. The OECD differs between the ready biodegradability and the inherent biodegradability. If the criteria of ready biodegradability are not reached, the inherent degradability should be tested in the next step. The OECD test methods are required for classification and approval of different product groups and are selected in dependence of the substance properties.
The GLP biodegradation laboratory within the InterBioTox cluster has many years of experience and can help you to suggest the right strategy to evaluate a potential persistency of your substance/product.
We offer the following test methods performed according to latest OECD Guidelines based on substances properties and based on your particular requirements:
A classification of biodegradability made by the OECD describing the degradation of an organic substance under aerobic conditions to carbon dioxide (CO2), water (H2O), and minerals by aerobic bacteria as determined by the measured change of Dissolved Organic Carbon (DOC), Biological Oxygen Demand (BOD), or CO2 evolution over time. A passing substance has to reach either a 60% BOD or theoretical CO2 evolution, or 70% decrease in DOC, depending on test method, all of which use a 10 - day window within a maximum 28-day test period for a successful determination. Readily biodegradable is defined as well as the ability of a product to biodegrade quickly and completely.
|OECD 301A||DOC-Die-Away Test||water soluble, not volatile|
|OECD 301B||CO2-Evolution Test (Sturm Test)||insoluble in water, not volatile|
|OECD 301D||Closed-Bottle Test||poor water soluble, volatile|
|OECD 301F||Manometric Respirometry Test||insoluble in water, volatile|
|OECD 310||CO2-Headspace Test||volatile|
The following table shows the different Biodegradation Tests according OECD 301 which are applied in dependence of the substance properties.
|Test||Analytical method||Suitability for compounds which are:|
|DOC Die-Away (301A)||Dissolved organic carbon||-||-||+/-|
|Co2 Evolution (301B)||Respirometry: CO2 evolution||+||-||+|
|Closed Bottle (301D)||Respirometry: dissolved oxygen||+/-||+||+|
|Manometric Respirometry (301F)||Oxygen consumption||+||+/-||+|
Inherent biodegradability refers to tests with a longer exposure of a test substance to microorganisms. Using favourable conditions, the tests of inherent biodegradability have been designed to assess whether the chemical has any potential for biodegradation under aerobic conditions. Inherently biodegradable is defined as the characteristic of a product to be consumed by naturally occurring organisms in nature over an indefinite period of time (> 20% but < 60% as measured by ready biodegradability testing).
|OECD 302B||Zahn-Wellens / EMPA Test||insoluble in water, not volatile, filterable|
Special Biodegradation Tests
InterBiotox offers also special biodegradation studies in anaerobic conditions simulating the conditions similar to an anaerobic digester. The other biodegradation studies simulates the biotic degradation of plastic materials in an aqueous medium.
|OECD 311/ISO 11734||Anaerobic Biodegradability of Organic Compounds in Digested Sludge|
|EN ISO 14851:2019||Determination of the ultimate aerobic biodegradability of plastic materials in an aqueous medium - Method by measuring the oxygen demand in a closed respirometer|
|EN ISO 14852:2018||Determination of the ultimate aerobic biodegradability of plastic materials in an aqueous medium - Method by analysis of evolved carbon dioxide|
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