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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Biodegradation in water: screening test: Weight of evidence: Experimental results and (Q)SAR estimation on ready biodegradability and experimental results on inherent biodegradability. 

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

Biodegradation in water: screening test: Weight of evidence: Experimental results and (Q)SAR estimation on ready biodegradability and experimental results on inherent biodegradability.

Using the BIOWIN v4.10 model of EPI Suite v3.20, trichloroacetic acid is not readily biodegradable.

In a modified MITI-I Test (OECD Guideline 301C), trichloroacetic acid, present at 100 mg/L, reached 7% of its theoretical BOD after four weeks incubation with activated sludge inoculum (30 mg/L). Under test conditions no biodegradation was observed.

In the respirometric test (OECD Guideline 301F) with DOC concentrations of 1 -300 mg/L, trichloroacetic acid was degraded to <5% (BOD/COD) after 7 days with activated sludge from an industrial sewage treatment plant (200 mg/L). Therefore, trichloroacetic acid is not readily biodegradable.

With an inoculum (100 mg/L) from 10 different locations which were partially polluted with chemicals, including municipal and industrial sewage treatment plants and surface water bodies, 100 mg trichloroacetic acid/L was degraded within 28 days to 0-46 % under aerobic conditions (OECD Guideline 302C, "Inherent Biodegradability, Modified MITI Test II").

In two Zahn-Wellens tests (inherent biodegradability OECD 302B) with industrial activated sludge, the substance trichloroacetic acid proved to be non biodegradable.

Based on all the reported results, it is concluded that trichloroacetic acid is not readily biodegradable in water.