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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

TCPP has to be classified as not readily biodegradable. TCPP is regarded as inherently biodegradable with a degradation of 95 % within 64 days, but for STP degradation assumptions were not fulfilled due to the long adaptation phase.

Key value for chemical safety assessment

Biodegradation in water:
inherently biodegradable

Additional information

In a test on ready biodegradability of TCPP conducted according to the EU-method C.4 -D (Determination of the Ready biodegradability: Manometric Respirometry Test) 14 % degradation was observed after 28 days (Bayer AG, 1991). Based on this result the substance should be regarded as not readily biodegradable.

The result is supported by an aerobic ready test, performed according to the national Japanese standard method comparable to the OECD TG 301 C guideline. After a period of 4 weeks no biodegradation of TCPP was observed (MITI, 1992).

The potential for inherent biodegradation of TCPP is described, based on two available biodegradation tests. A prolonged closed bottle test, performed according to EU Method C.6, TCPP showed 13 % degradation after 28 days, but at the end of the study (84 days) the oxygen consumption was equivalent to complete mineralisation (Van der Togt and Van Ginkel, 2002). Based on this result, the substance can be considered as inherently biodegradable under aerobic conditions. This conclusion is supported by another experiment on inherent biodegradability of TCPP. Biodegradation was assessed in a SCAS test conducted according to the OECD TG 302 A guideline over a period of 64 days. After an acclimation phase of 21 days, rapid degradation was observed. As the biodegradation percentage calculated was 95, TCPP is considered as inherently biodegradable (Van Ginkel, 2001). The criteria for applying the degradation rates of inherent biodegradable substances to the STP degradation assumptions were not fulfilled due to the long adaptation phase.