N-(3-aminopropyl)-N- (C12-18 even numbered) alkyl-propane-1,3-diamine

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

2.74 µg/L

Assessment factor:

50

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

2.23 µg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.274 µg/L

Assessment factor:

500

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

1.6 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

109.6 mg/kg sediment dw

Assessment factor:

1

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

11 mg/kg sediment dw

Assessment factor:

1

Extrapolation method:

equilibrium partitioning method

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

10 mg/kg soil dw

Assessment factor:

100

Extrapolation method:

assessment factor

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

PNEC oral

PNEC value:

0.22 mg/kg food

Assessment factor:

300

Additional information

Since the linear N-C16-18 (evennumbered) C18 unsaturated dipropylene triamines and tripropylenetetraamines are poorly soluble in water, and as they are positively charged under environmental conditions, it is very likely that they adsorb soil, sediment and other negatively charged surfaces. The results of ecotoxicity testing in synthetic growth media are therefore influenced by secondary effects like sorption to glassware. In order to reduce the influence of these secondary effects, modifications such as river water tests (or tests in the presence of humic acids) can be introduced as stabilizer of the test substances which limit the sorption glassware and at the same time creates more realistic conditions. These studies should therefore be considered as higher tier studies.

For the aquatic risk assessment of strongly sorbing substances the current REACH Guidance Documents do not provide sufficient guidance concerning both effects and exposure assessment. The best and most realistic alternative for strongly sorbing substances is the PEC/PNEC_{aquatic bulk} approach (ECETOC 2003). This approach is based on a PNEC_{aquatic bulk} which is derived from a modified ecotoxicity test using humic acid, natural water or effluent and a PEC_{local, aquatic bulk} which represents the total aquatic concentration (dissolved and sorbed = bulk). The risk quotient for the aquatic compartment is calculated by using nominal concentrations.

Conclusion on classification

For the environmental classification of Triamine C12-18, C18 unsaturated no read across from other substances is required as there are two long term study endpoints for the substance available.

 

The two long term studies available with Triamine C12-18, C18 unsaturated (old CAS no: 91771-18-5, new CAS no: 1219458-12-4) were performed in natural river water (pH 7.9-8.1, DOC 2.8 -3.0 mg/L, total hardness 322-338 mg/L).

 

The reasoning for performing tests in river water is based on the problems when performing ecotoxicity tests with these substances (in PNEC derivation) and the erroneous prediction of the fraction dissolved (in PEC derivation). The environmental risk is normally evaluated based on the ratio of the PEC and PNEC dissolved. Because the calculation of the fraction dissolved is assuming only sorption to organic matter the bioavailable fraction is overestimated. During ecotoxicity testing with these substances problems observed are sorption to test organisms, glassware, tests performed above the CMC, no reproducible test results.

In order to reduce the influence of these secondary effects, modifications such as river water tests (or tests in the presence of humic acids) can be introduced as stabilizers of the test substances, which limits the sorption to organisms and glassware and at the same time creates more realistic conditions. Testing the polyamines under more realistic conditions in the presence of humic acids or in river water indicate that bioavailability is lower compared to studies using standard media. Following the reasoning above, tests were conducted under environmentally realistic conditions (i.e. in river water with moderate to low DOC and suspended content)

The risk assessment of these substances is thus not based on the ratio PEC/PNEC dissolved but on the ratio PEC/PNEC total(bulk).

 

An additional advantage of this method is that not the dissolved concentration needs to be quantified in the ecotoxicity tests but only the total concentration. Quantification of these substances is E.g. check if the stock solution is actually containing the nominal concentration and/or the initial concentration is ≥80% of the nominal. This was checked during both long term tests and at the ErC10 and NOEC more than 80% of the nominal was observed in the test solutions allowing the use of the nominal test concentration for the derivation of the dose-response curves. Sorption to glassware at the end of the test was observed to be minimal and biodegradation of the substance is considered negligible during the short time frame of the test (semi-static interval).

The bulk approach was accepted by EU regulators for the EU-risk assessments of DODMAC and primary alkylamines.

 

The results of both Triamine C12-18, C18 unsaturated tests are therefore based on nominal test concentrations:

·        The algae test (Noack 2010) with Cocodipropylenetriamine gave an ErC50 of 223 µg/L and an ErC10 of 137 µg/L.

·        The long term daphnia test with Cocodipropylenetriamine gave a NOEC (reproduction) of 270 µg/L and an EC50 adult mortality of 342 µg/L. For the derivation of the PNEC however the EC10 for adult mortalilty of 235 µg/L was used as a worst-case.

 

For risk assessment the bulk approach data can be used directly but for classification, the river water data are corrected with a factor of 10 to compensate for the mitigation by river water constituents. This means that it is assumed that 90% of the substance will not be available in the test to cause any effects. When calculating the fraction sorbed using the standard equations (only based on hydrophobic sorption to organic matter) only 43% is assumed to be sorbed (in surface water).

 

The data used for the acute classification are the corrected ErC50 of 0.0223 mg/L and the corrected EC50 adult mortality of 0.0342 mg/L. The lowest value is within the range: 0.01 < L(E)C50 ≤ 0.1 mg/L.

This leads to an acute 1 classification and an M-factor of 10.

 

The data used for the chronic classification are the corrected ErC10 of 0.0137 mg/L and the corrected NOEC of 0.0235 mg/L. The lowest value is within the range: 0.01 < NOEC≤ 0.1

This leads to a chronic 1 classification and no M-factor because the substance is rapidly biodegradable (RD)