Tris(2-hydroxyethyl)ammonium acetate

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.1 mg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

1 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.01 mg/L

Assessment factor:

10 000

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

10 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

0.085 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.009 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

0.017 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

PNEC oral

PNEC value:

6.67 mg/kg food

Assessment factor:

300

Additional information

For ecotoxicological risk assessment purposes, EUSES 2.1 software was utilised to obtain some PNEC values.

As no information on long-term toxicity was available for all the three trophic levels (the only valid NOEC value was derived from algae), short-term EC50 experimental results were used. This implies the use of the highest assessment factors in order to perform the most conservative risk assessment.

Sediment (freshwater and marine water) and soil PNECs were derived from the EUSES results, utilising the partition coefficient method.

The oral PNEC calculation was based on a 28-day NOAEL experimental result on rats using the assessment factor method.

An additional calculation of PNECs was also carried out following the “Guidance on information requirements and chemical safety assessment (Chapter R.10: Characterisation of dose (concentration)-response for environment)” for freshwater, marine water, intermittent releases, STP and sediment in fresh and salt water, using the corresponding assessment factors and calculations. These PNECs were the same as those obtained from the EUSES calculations.

 

Sediment (freshwater and marine water) and soil PNECs were derived from the EUSES results, utilising the partition coefficient method.

 

The oral PNEC calculation was based on a 28-day NOAEL experimental result on rats using the assessment factor method.

 

The EUSES risk assessment failed for fresh water and marine water compartments (RCR>1). This is due to the high assessment factors used for the PNEC calculations in these compartments. Nevertheless, short-term toxicities associated with Triethanol amineacetate show that the substance is of very low concern to vegetative and animal species. Moreover, exposure to aquatic compartments is very unlikely, as risk management measures are implemented during the process of manufacture and no releases to the environment are expected during the life cycle of the substance.

 

Based on the above and together with classification considerations, it is evident that Triethanol amineacetate is a substance of low environmental concern.

Conclusion on classification

According to Regulation (EC) No. 1272/2008, a substance poses an acute aquatic hazard if the 96 hour LC50 for fish is 1 mg/l or less. A 96 hour study was carried out with Triethanol amineacetate on carp, and the LC50 was determined to be greater than 100 mg/l. Similar results were obtained for tests carried out with Read Across substance 2 (RA2) on rainbow trout (>120 mg/l) and with Read Across substance 1 (RA1) on zebra fish (>125 mg/l). Also, according to Regulation (EC) No. 1272/2008, a substance poses an acute aquatic hazard if the 72 or 96 hour EC50 for algae is 1 mg/l or less. EC50 for Triethanol amineacetate and for the read across substance RA2 were >100 mg/l for both similar-structural substances, For crustacea studies cut off value for classification is an EC50 ≤1 mg/l. Read across substances RA2 and RA1 shows EC50 values >100 mg/l and >125 mg/l respectively. Since sameness has been established for these read across substances and Triethanol amineacetate, these results further prove the non-toxic nature of Triethanol amineacetate.

 

The potential for bioaccumulation is determined using the octanol/water partition coefficient (Log K_ow). According to Regulation (EC) No. 1272/2008, a cut-off value of Log K_ow≥ 4 can be used to identify substances with a real potential to bioconcentrate. The partition coefficient of Triethanol amineacetate was determined to be less than -1.31, which indicates a low potential for bioaccumulation. Also, according to Regulation (EC) No. 1272/2008, a bioconcentration factor (BCF) in fish of ≥ 500 is indicative of the potential to bioconcentrate. The BCF in fish of Triethanol amineacetate was determined to be 1.41 using EUSES 2.1. Therefore Triethanol amineacetate is not classified as bioaccumulative.

 

Substances that rapidly degrade can be quickly removed from the environment. A ready biodegradability test was carried out on Triethanol amineacetate, and the criterion for ready biodegradability was not met (according to Regulation (EC) No. 1272/2008, for tests based on CO₂generation: 60 % biodegradation within 10 days). However it biodegraded significantly during the test period (50 and 63 %) and thus it is inherently biodegradable.

 

In conclusion, Triethanol amineacetate is not classified as harmful to the aquatic environment as it is not persistent, bioaccumulative or toxic.