Standard Tests for Biodegradation

Standard Tests for Biodegradable Polymers using Liquid Media... 

The indiscriminate use of the green prefix Eco illustrates the need to demonstrate in each case ultimate bioassimilation by the application of standard tests for biodegradable plastics in order to advise the user in their use and to avoid long-term pollution of the environment. This has already been discussed in more detail in Chapter 12. 

Standard tests for determination of the ready biodegradability of organic substances are developed by a number of organisations including OECD (OECD Test Guidelines 301A-F), EU (C.4 tests), OPPTS (835.3110) and ISO (9408,9439,10707). 

Because of the central role that estimates of biodegradability play in environmental impact assessments, a great deal of effort has been devoted to developing standardized test procedures (Gerike and Fischer 1981). In spite of this, conventional tests for biodegradability under aerobic conditions retain some questionable, or even undesirable, features from an environmental point of view. Attention is therefore drawn to two valuable critiques of widely used procedures (Howard and Banerjee 1984 Battersby 1990). Some of the important issues in the design of such tests are therefore only briefly summarized here. 

Standard tests for estimating the biodegradation of materials in a given environment have been reviewed in this paper. Several conclusions arise ... 

A standard test for the presence of organic pollutants within liquids. It is, in effect, a measure of the content of biodegradable material. 

All standards determine that each material or product component with a concentration of more than 1 % has to be tested for biodegradability. In addition, DIN EN 13432, DIN EN 14995, ISO 17088 as well as the JBPA certification program require that the total sum of organic compounds for which biodegradability does not have to be determined, may not exceed 5 wt.% (based on product weight). 

There have been numerous communications on the subject of biodegradation test methods, including aerobic compost (30), anaerobic bioreactor (31), general methodology and future directions (32—34), and a fine review article (24). ASTM (22) and MITI (35) have also set forth standard testing protocols for plastics, as shown in Table 2, whereas OECD test methods (29) are more suited to water-soluble polymers. 

Membrane manufacturers require a standard test to maintain batch-to-batch quality. Few use proteins. Materials selected are ones for which the complications are minimized, the probe is simple, fast, and cheap to detecl , does not readily biodegrade, and gives results, whatever they are, which are reproducible. There is no standardization of these tests within the industry. 

Calmon-Deeriaud, A. Bellon-Maurel, V, Silvestre, K Standard Methods for Testing the Aerobic Biodegradation of Polymeric Materials, Vol 135, pp. 207-226. 

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