Amines, N-(C16-18 and C18-unsatd. alkyl)trimethylenedi-, N-(hydroxyethyl) derivs.

Biodegradation in water and sediment: simulation tests

Description of key information

A waste water treatment simulation test was performed with ethanol, 2,2’-[[3-[2-hydroxyethyl]amino]propyl]-iminobis-, N-(hydrogenated tallow alkyl) derivatives. A removal of >99.97% was observed using specific chemical analyses (LC-MS/MS) of the effluent. Also the sorption to sludge was measured and this accounted for 3.8 % of the total removal.  Biodegradation is therefore responsible for 96.2% of the removal.

Key value for chemical safety assessment

Half-life in freshwater sediment:

30 000 d

at the temperature of:

12 °C

Additional information

The removal of ethanol, 2,2’-[[3-[2-hydroxyethyl]amino]propyl]-iminobis-, N-(hydrogenated tallow alkyl) derivatives in biological treatment plants was simulated in a continuously-fed activated sludge (CAS) unit fed with domestic wastewater. Ethanol, 2,2’-[[3-[2-hydroxyethyl]amino]propyl]-iminobis-, N-(hydrogenated tallow alkyl) derivatives were spiked at a nominal influent concentration of 28.3 mg/L (20.0 mg/L carbon; calculated) for a period of 62 days and included a control fed with domestic wastewater only. The immediate high carbon removal percentages can be attributed to adsorption and probably biodegradation. The mean carbon removal percentage of ethanol, 2,2’-[[3-[2-hydroxyethyl]amino]propyl]-iminobis-, N-(hydrogenated tallow alkyl) derivatives calculated over 15 measurements obtained from day 47 to 62 of the test was 99 ± 2% (95% confidence interval). These high removal percentages strongly indicate that ethanol, 2,2’-[[3-[2-hydroxyethyl]amino]propyl]-iminobis-, N-(hydrogenated tallow alkyl) derivatives is biodegraded completely. Formation of water soluble compounds during biological treatment of ethanol, 2,2’-[[3-[2-hydroxyethyl]amino]propyl]-iminobis-, N-(hydrogenated tallow alkyl) derivatives can be excluded. An accurate assessment of the removal of 2,2’-[[3-[2-hydroxyethyl]amino]propyl]-iminobis-, N-(hydrogenated tallow alkyl) derivatives was established with specific analyses. A removal percentage of >99.97 was observed for ethanol, 2,2’-[[3 -[2-hydroxyethyl]amino]propyl]-iminobis-, N-(hydrogenated tallow alkyl) derivatives in a waste water treatment simulation test. Adsorption accounted for only 3.8% of the total removal whereas biodegradation was responsible for 96.2% of the observed removal from the wastewater

In conclusion, the CAS test demonstrates that ethanol, 2,2’-[[3-[2-hydroxyethyl]amino]propyl]-iminobis-, N-(hydrogenated tallow alkyl) derivatives is almost completely removed from the wastewater in conventional biological wastewater treatment plants. Ethanol, 2,2’-[[3-[2-hydroxyethyl]amino]propyl]-iminobis-, N-(hydrogenated tallow alkyl) derivatives is primarily removed by biodegradation.

This test result of ethanol, 2,2’-[[3-[2-hydroxyethyl]amino]propyl]-iminobis-, N-(hydrogenated tallow alkyl) derivatives can be used for the other ethanol, 2,2’-[[3-[2-hydroxyethyl]amino]propyl]iminobis-, N-alkyl derivativesas a worst-case because all ethoxylated alkyl-1,3-diaminopropanes tested are readily biodegradable and the reduced sorption is expected for fatty amine derivatives with shorter alkyl chains is compensated by higher removal by biodegradation.

The Kpsed was determined as 43274 L/kg. The suggested maximum half-life for a readily degradable substance with a Kpsed in the range >10000 and < 100000 L/kg is 30000 days (at 12 ºC). These values are considered as extremely conservative but in the absence of measured data will be used in the exposure assessment as a worst-case.The half-life of the bioavailable fraction of ethoxylated diamines in the water phase of soils is expected to be in the order of a few days,which is based on experiments with dialkyldimethylammonium salts (van Ginkel et al, 2003).