Biodegradability test analysis

During a soil burial biodegradation test for 27 months, samples specimen were withdrawn at time intervals and characterized by means of structural and thermal analysis. This method allows to watch any progress of oxidative degradation as a direct effect of the incubation in an active microbial environment. 

A new biodegradation test method for bioplastics was first developed at ASTM level as ASTM D5511-94. Later, in 2004, the same method was published as ISO 15985-Plastics - Evaluation of the ultimate anaerobic biodegradability and disintegration under high solids anaerobic digestion conditions Method by analysis of released biogas. 

Development of the Screening Test Method for Biodegradation by Analysis of Evolved Carbon Dioxide... 

A preliminary test for the biodegradability of the 3-phenyl- and 3-carbamoyl-2(lH)pyridones was conducted in a barnyard humus suspension. The analysis by HPLC showed some loss, and the fluorescent compounds seemed to be adsorbed onto the solid. The 3-carbamoyl-2(lH)pyridone (II) also hydrolyzed to 3-carboxylic acid-2(lH)pyridone both in the slurry test and in water solutions that had been left standing 1-2 weeks. In preliminary tests both the 3-phenyl- and the 3-carbamoyl-2(lH)pyridones apparently adsorbed to some extent on silica sand columns. In addition, the solubility of both 1-H compounds was somewhat low, 1.3 x 10 M for II, and 1.0 x 10 M for IV. 

The data base for biodegradation information consisted of 5-day BOD tests that were screened from the literature using a systematic review procedure (13). A total of 340 chemicals was Included In this analysis. In contrast, the data base for log P values is much larger because Leo and Weinlnger (14) have developed an additive model to estimate log P for chemicals. Their model also gives an estimate for the confidence in the estimated value of log P. Here we used a data base of 1700 chemicals that were determined by Leo and Weinlnger (14) to have a high confidence in the estimated value of log P. 

As with the studies on the herbicide spray equipment testing grids at Eglln AFB, Florida, the studies of the biodegradation plots confirmed the presence and persistence of TCDD. Analysis of soil samples collected from the Utah plots in 1978 indicated that 85 percent of the amount of TCDD originally extracted In 1972 could be recovered, suggesting that TCDD applied subsurface was minimally disappearing. 

The Acyclic Aliphatic and Monocyclic Aromatic models were developed during an evaluation of other biodegradation prediction models. As Table 12.6 indicates, the two models were developed with seven structural fragments (acyclic aliphatic) and nine structural fragments (monocyclic aromatic) by means of discriminant analysis with MITI test data. 

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