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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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Description of key information

- Biodegradation in water: No standard tests with surface water available. Rapid degradation in different water samples, mainly due to abiotic processes.
- Biodegradation in sediment: no tests available. Rapid decomposition can be expected due to the physicochemical properties of peracetic acid (high water solubility; low Koc).
- Biodegradation in effluents from a sewage treatment plant: DT50 in the STP effluent: << 5 minutes

Key value for chemical safety assessment

Half-life in freshwater:
5 min
at the temperature of:
20 °C

Additional information

Biodegradation in water

There are a few studies on the biodegradation in water available, but which have been not conducted according to GLP and required the test methods. In general, the tests show that the dissipation of peracetic acid increases with increasing salinity (decomposition in demineralised water tap water seawater) and with increasing content of organic substance. The highest degradation was measured to be 50% within 2 minutes in seawater (Kuhn, 2000) and 95.1% within 1 day in drinking water (Teral and Harmon, 1995). The lowest degradation was measured to be 25.6% within 5 days in lake water (Chalkley, 1991a; 1991b). Based on the available data, no reliable half-life value can be calculated from the existing data for fresh water. Moreover it can be assumed that the degradation observed in these studies was mainly due to abiotic decomposition / degradation processes.

The treatment of effluent water from STPs (with the aim to reduce coliform bacteria before release into surface water) is an important use of peracetic acid in some EU countries. For this reason, the degradation of peracetic acid in effluent water from an STP was measured in a laboratory test (Van Egdom, 2007). Within 5 minutes after addition of peracetic acid to the sewage water, the of peracetic acid concentration dropped below the LOQ (0.1 mg/L). Consequently, the DT50 in the STP effluent is << 5 minutes.

It can be assumed that the contents of organic substance and transition metal components are the factors determining the decomposition of peracetic acid and that their content is higher in sewer waters entering an STP than in the effluent stream.

Biodegradation in sediment

No data on the biodegradation of peracetic acid in sediment is available, since an adsorption of peracetic acid to sediment is not likely to occur due to the physical/chemical properties. The solubility of peracetic acid is high (> 106 mg/L) and the calculated mean Koc is rather low (1.06). These values indicate that peracetic acid will remain in the water phase. Moreover, peracetic acid degrades rapidly in contact with organic substance so that any amount of peracetic acid which comes in contact with the sediment is consequently rapidly decomposed.