2-piperazin-1-ylethanol

Endpoint summary

Description of key information

With high probability not acutely harmful to aquatic organisms.

Additional information

Short-term toxicity to fish: With high probability not acutely harmful to fish.

The toxic effect of 2 -piperazin-1-ylethanol (CAS 103-76-4) was studied with Pimephales promelas as test species under flow-through conditions performed similar to OECD 203 (Geiger et al., 1986). The test item concentrations were analytically verified. The 96-h LC50 was determined to be 6410 mg/L using pH-adjusted test solutions.

In another study according to German Industrial Standard DIN 38412, part 15, the toxic effect to the test species Leuciscus idus was studies under static exposure conditions. The test species was Leuciscus idus. The test item concentrations were not analyticaly verified. The 96 -h LC50 was determined to be 681 mg/L based on not pH-adjusted test solutions (geometric mean of LC0 and LC100; pH 7.7 to 10.9). A pH-adjusted test sample of 4640 mg/L caused no mortality (pH 7.2 to 8.0; BASF AG, 1988; report no. 10F0724/875016).

In a third study performed according to OECD 203, the test species was Oncorhynchus mykiss which was exposed under semi-static conditions with daily exchange of the test solutions. The pH of the test solutions was not adjusted and thus ranging from pH 8.7 to 9.9. The test item concentrations were not analytically verified. The 96-h LC50 was determined to be 750 mg/L.

The study by Geiger et al. (1986) was selected as key study, since the test concentrations were analytically verified and the test solutions were pH-adjusted. The data from the not pH-adjusted test solutions gave LC50 values of about the same level. These results are regarded as supporting studies and represent the effect level without pH-adjustment.

In conclusion, the substance is with high probability acutely not harmful to fish.

Short-term toxicity to aquatic invertebrates: With high probability not acutely harmful to aquatic invertebrates.

The acute effects of hydroxyethylpiperazine (CAS 103 -76 -4) to aquatic invertebrates are assessed in a weight-of-evidence approach using QSAR data. Only those results were considered where the substance was in the applicability domain of the model. The following QSAR models were used to derive an acute E(L)C50:

- QSAR Toolbox v4.4: Branchiopoda E(L)C50 (48 h): 256 mg/L

- US EPA T.E.S.T. v4.2.1: Daphnia magna LC50 (48 h): 295 mg/L

- EPI Suite v4.11 - ECOSAR v1.11: Daphnid LC50 (48 h): 379 mg/L (aliphatic amines)

It can be concluded that the substance is with high probability acutely not harmful to aquatic invertebrates.

For evaluation purposes an EC50 of 256 mg/L is used.

Long-term toxicity to aquatic invertebrates: Chronic effects of 2 -piperazin-1 -ylethanol are not expected towards aquatic invertebrates.

Experimental data are available on the long-term toxicity of 2-piperazin-1-ylethanol (CAS 103 -76 -4) towards aquatic invertebrates. A GLP guideline study according to OECD 211 was performed as limit test, using Daphnia magna as test organism. A test concentration of 12 mg/L was used, as no effects have been observed at this concentration level in a previous range-finding test. After 21 days no effects were observed regarding immobility and reproduction. Therefore, the NOEC was determined to be >= 12 mg/L (nominal, analytically verified; BASF SE, 2019, report no.: 51E0573/15E065).

It can be concluded, that chronic effects of 2 -piperazin-1 -ylethanol are not expected towards aquatic invertebrates.

Toxicity to aquatic algae and cyanobacteria: With high probability not acutely harmful to algae

The toxic effects of hydroxyethylpiperazine (HEP; CAS 103-76-4) on aquatic algae and cyanobacteria were studied in two growth inhibition tests. Eide-Haugmo et al. (2009/2012) studied the effect on the marine algae Skeletonema costata. The growth inhibition test was performed according to ISO 10253. The test conditions were static. Test concentrations were not analytically verified, but are assumed to be stable: 1) the substance is not readily biodegradable, 2) it is not expected to evaporate from the water surface based on a low Henry’s Law constant (HLC =2.37E-8 Pa*m³/mol), and 3) adsorption is not expected due to a low adsorption coefficient (log Koc = 1.2 at pH 7). Based on nominal test concentrations, the 72-h ErC50 was determined to be 329 mg/L.

A supporting study was conducted according to OECD TG 201A with hydroxyethylpiperazine as part of a mixture (approximately 38% HEP; BASF SE, 2012, report no.: 60E0722/11E129). Pseudokirchneriella subcapitata was used as test species. Based on analytically verified nominal test concentrations the 72 -h ErC10 and the 72-h ErC50 were determined to be >120 mg/L (based on test substance mass without correction for purity = mixture).For the evaluation, based on the fraction of HEP in the mixture, the 72-h ErC10 of HEP was calculated to be > 45.6 mg/L (worst-case approach, not considering potential mixture toxicity). This value was used for further evaluation of the long-term toxicity.

In conclusion, the substance is with high probability acutely not harmful to algae.

Toxicity to microorganisms: The inhibition of the degradation activity of activated sludge is not anticipated when introduced in appropriately low concentrations.

The toxicity to microorganisms was assessed in a weight-of-evidence approach based on two experimental studies. One of these studies was not performed with the pure test substance, but with a mixture of piperazines.

A study on inhibitory effects of hydroxyethylpiperazine (HEP; CAS 103 -76 -4) on a single microbial species was conducted according to ISO 10712 (Pseudomonas, cell multiplication inhibition test; Akzo-Nobel, 1996; report no.: 142/267). Based on nominal test concentrations, the 16-h EC10 and 16-h EC50 were determined to be 14 mg/L and 100 mg/L, respectively. However, according to the REACh guidance document (ECHA, 2014) chapter R.7b the results of the cell multiplication inhibition test with P. putida (Bringmann and Kühn, 1980; ISO 10712, 1996) should be used for calculation of the PNECmicro-organisms only in cases where no other test results are available. 

The second study was performed with hydroxyethylpiperazine as part of a mixture (approximately 38% HEP). Short-term effects of the hydroxyethylpiperazine mixture (piperazine: 14.57 %, HEP: 37.768 %, DiHEP: 19.90 %) on the respiration rate of domestic activated sludge were studied in an OECD 209 GLP guideline study. No inhibitory effects were observed. The 3-h EC10 was > 1000 mg/L (BASF, 2012; report no.: 08G0722/11G120). Based on the fraction of HEP in the mixture, the 3-h EC10 is estimated to be > 380 mg/L (worst-case approach; not considering potential mixture toxicity). This value was used for the PNEC calculation.

It can be concluded that inhibition of the degradation activity of activated sludge is not anticipated when introduced in appropriately low concentrations.