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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Based on the available dataset, TBEP has to be considered as readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

Available biodegradation data

An overview of the six endpoint study records dealing with biodegradation data on TBEP is given in the table below.

Method

Duration

Inoculum

Test conditions

Parameter

Result

Reference

Reliability

OECD 301 B

EC Method C.4

28 d

AS from domestic STP (adaptation not stated)

Loading rate 30 mg ss/L,

room T°,

aerobic, TC = 18.4 mg/L

Inorg. C anal.

87% after 28 days

Mead C & Handley JW (1998)

2

SCAS Test 28 d AS not adapted Dark, room T°, aerobic, TC = 3 - 13 mg/L Test substance concentration 88% after 28 days at 3 mg/L cycle55% after 28d at 13 mg/L cycle. Hicks O et al (1976)

 2

MITI Test OECD 302C 4 wk AS not adapted 25°C, aerobic, TC = 30 -100 mg/L N/A 0% after 4 weeks MITI (1992)

 4

EC Method C.4 15 d Micro-organisms in river or marine water TC = 1 mg/L N/A 100% after 15 days Hattori Y et al (1981)

 4

River die-away test

30 d N/A Aerobic Test substance concentration 100% after 30 days Kawai S et al. (1985)

 4

Monitoring in STP N/A AS from STP Aerobic N/A ca. 81% Fukushima M et al (1992)

 4

AS: Activated Sludge - STP: Sewage treatment plant - T°: Temperature - TC: Test Concentration - ss: suspended solids - N/A: information not available

For three studies (Fukushima et al., 1992; Hattori et al., 1981; Kawai et al., 1985), as primary sources were not available, the corresponding records were assessed by reliability 4. The MITI test (1992) had also been assigned a reliability score of 4 because it was not conducted under GLP and no information is available on the substance tested nor on the validation of the study criteria's.

Conclusion

Based on available biodegradation data, TBEP is considered as readily biodegradable in accordance with the criterion in EU system (Directive 67/548/EC).