Biodegradability of Plastics in Sea water

The OECD 306B test deals with the biodegradability of plastics in sea water (94). This test is also known as the Zahn-WeUens/EVPA Test and included in a series of standards. Here, the shake flask method is used. 

The test substance is used in the test medium at a concentration of 5-40 mg of total organic carbon dissolved. No inoculum is added in addition to the microorganisms already present in the sea water. Stock solutions for mineral nutrients are containing minerals are shown in Table 1.11. 

Solution D Iron (III) chloride hexahydrate, FeCh x 6H2O 0.25 

A test medium is prepared by adding 1 ml of each of the stock solutions of Table 1.11 to 1 / of pre-treated sea water. The solution of the test substance in the test medium is incubated imder agitation in the dark or in diffuse light xmder aerobic conditions, at 15-20°C. Five flasks should be used  

Optionally, one additional flask is used containing a reference compound for procedure control and another containing the test substance and a sterilizing agent, e.g., mercury chloride, for abiotic sterile control. As reference compoimds, sodium benzoate, sodium acetate or aniline may be used. 

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