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Biodegradation in water: screening tests

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biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: well-documented paper, scientific acceptable, no information about GLP
according to guideline
other: MITI -I (OECD TG 301 C)
GLP compliance:
not specified
Oxygen conditions:
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
concentration of activated sludge: 30 mg/L
Duration of test (contact time):
4 wk
Initial conc.:
100 mg/L
Based on:
test mat.
Details on study design:
Test Equipment: Standard type
other: BOD (NH3)
Sampling time:
4 wk
Remarks on result:
other: indirect analysis
% degradation (TOC removal)
Sampling time:
4 wk
Remarks on result:
other: direct analysis
other: HPLC
Sampling time:
4 wk
Remarks on result:
other: direct analysis
Validity criteria fulfilled:
Interpretation of results:
readily biodegradable
The test substance dimethylamine is stated to be readily biodegradable.
Executive summary:

A biodegradation test according to MITI -I (OECD TG 301C) is reported by National Institute of Technology and Evaluation. An indirect analysis of BOD (NH3) gave a result of 88 % Degradation, direct analysis of TOC 96 %, respectively. The test period was 4 weeks, the chemical concentration 100 mg/L, and the concentration of the activated sludge was 30 mg/L. As overall result the test substance dimethylaminse is stated to be readily biodegradable.

Description of key information

According to test results the test substance can be declared as readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable
Type of water:
other: DMA was readily biodegradable in freshwater and marine water.

Additional information

Activated sludge was used as inoculum in an experiment which was published by National Institute of Technology and Evaluation (1975). Under aerobic conditions a BOD (NH3) of 88 % degradation was observed within 4 weeks and thus the test substance dimethylamine is stated to be readily biodegradable.

In an experiment by Hongwei, Zhanpeng, and Shaoqi (2006) the anaerobic biodegradability of nitrogenous compounds by common microorganisms in a wastewater treatment plant was investigated. As inoculum anaerobic sludge form digester tanks of a municipal STP in Beijing was chosen. The contact time was 50 days and the initial test substance concentration 100 mg/L, based on TOC. Dimethylamine was found to be readily biodegradable.

In another study where activated sludge and high purity oxygen – activated sludge were used as inoculum. Dimethylamine was removed consistently, averaging 81 and > 98 % during 4 month observations. The study was published by Sedlak, Deeb, Hawley, Mitch, Durbin, Mowbray, and Carr (2004).

Moreover, the biodegradability prediction of the active substance dimethylamine was calculated based on QSAR methods using the computer program from US-EPA (EPIWIN software: BIOWIN Program v4.10). Seven different models are used by this tool to predict as an overall result if the desired chemical is readily biodegradable or not. As newest model, Biowin 7 predicts additionally the biodegradation ability under anaerobic conditions.

According to the Linear and also Non-linear Model dimethylamine is biodegrading fast. The Ultimate Biodegradation Timeframe is given in weeks, whereas the Primary Biodegradation Timeframe shows days for the substance dimethylamine. Both MITI Models predict that it is readily biodegradable, which is also the prediction as overall result. Also under anaerobic conditions dimethylamine is suspected to be biodegraded fast.

Biodegradation of dimethylamine (DMA, CAS 124 -40 -3) and further 42 amine compounds was determined in a marine biodegradability test by Eide-Haugmo et al. (2012), conducted according to the OECD guideline 306, “Biodegradability in seawater” (OECD, 1992). As test medium for the biodegradation test, aged and fortified seawater was used. The seawater was collected from an expected non-polluted location (90 m depth in the Trondheimsfjord, Norway) and filtered, after which it was stored in the dark for 2–5 days in 10-L tanks at 20 ± 2°C for degradation of inherent organic materials (aging). The aged seawater was aerated for 20 min and fortified with nutrient solutions enhancing bacterial growth. Test solutions were prepared by diluting the compound tested to 2 mg/L. After an incubation period of 28 days degradation rate of DMA was 77.2% (BOD28, based on % of ThOD).