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Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Biodegradation:

Inherently biodegradable (WoE, OECD 302 B, OECD 301 D)

Additional information

A reliable study (Hoechst_1984, reliability 2) on inherent biodegradation, which was performed according to OECD-Guideline 302 B (Zahn-Wellens), shows 2-chlorobenzaldhyde to be inherently biodegradable: 2 -chlorobenzaldehyde was degraded in experiment A (151.0 mg/L DOC initial concentration) within 10 days of incubation by 95% and in experiment B (300.0 mg/L DOC initial concentration) within a 10 day window by about 75% at day 16 and by more than 95% at the end of the experiment (day 22). The study therefore shows the inherent, ultimate biodegradability of the test substance.

In another reliable study (Wellens_1990, reliability 2) performed also according to OECD-Guideline 302 B (Zahn-Wellens), within 13 days 100% of 2 -chlorobenzaldehyde was degraded and degradation proceeded in a 3 - day window corroborating the conclusion from the first study.

A insufficiently documented (therefore reliability category 3) study on ready biodegradability performed similar to Closed Bottle (OECD 301 D) with nonadaptedinoculum resulted in a degradation of 63 % (BOD) in a 10 day window within 20 days (Bayer_1973), fulfilling the requirements for ready biodegradability.

In a weight-of-evidence evaluation of these three studies it is concluded that 2 -chlorobenzaldehyde should be regarded as (at least) inherently biodegradable.

This conclusion is supported by an additional, less documented study on inherent biodegradation (Hoechst_1986, RL3), whereas a study performed according to OECD-Guideline 301 C (MITI I), reported in a secondary source only (reliability not assignable, RL4), failed to prove ready biodegradability. As this study is lacking important information, e.g. a reference substance demonstrating the functionality of the test conditions, its reliability is doubtful. In conclusion, the unequivocal results of the four other studies are not put into question by the MITI-study.