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Environmental fate & pathways

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In a test on ready biodegradability 83 -94% of the applied TPP was degraded after 28 days of incubation. Thus TPP can be classified as readily biodegradable. Similarly, in a test simulating of an aerobic sewage treatment plant a mean elimination rate of 93.8% was determined after 20 days. Other studies have given similar results showing that TPP is readily degraded in water/sediment systems.

TPP can also be degraded under anaerobic aquatic conditions in the presence of river sediment.

In soil under aerobic conditions, the amount of TPP decreased steadily with time and accounted for 46.6% of that applied after 32 days. However, degradation slowed and 20.2% of the applied test substance was recovered after 101 days. In heat sterilized soil under the same conditions mainly unchanged TPP was recovered after 101 days incubation. This indicates that the degradation in soil is mostly microbial. Under anaerobic conditions in soil degradation was equally rapid and extensive as under aerobic conditions as the amount of extractable radioactivity represented 35.8% of the applied dose after 102 days. Under aerobic conditions a DT50 of 37 days can be calculated and under anaerobic conditions 21 days.

The results obtained show that TPP is unlikely to be persistent in the environment.