1-butylpyrrolidin-2-one

Endpoint summary

Additional information

Acute toxicity to fish:

A study was performed to assess the acute toxicity of N-Butylpyrrolidone to Rainbow trout (Oncorhynchus mykiss), following OECD Guideline No 203 (1992), and EU Method C. 1 of Commission Regulation (EC) No. 440/2008. Seven fish were exposed to an aqueous solution of the test item, at a single concentration level of 100 mg/L for a period of 96 hours at a temperature of 14 °C under semi-static test conditions.

Analysis of the 100 mg/L test preparation at 0 and 72 hours (fresh media) and at 24 and 96 hours (old media) showed measured test concentrations to range from 88 % to 95 % of nominal and so the results are based on nominal test concentrations only. There were no mortalities in 7 fish exposed to a test concentration of 100 mg/L for a period of 96 hours. The results of the definitive test showed the highest test concentration resulting in 0 % mortality to be 100 mg/L (LC50 > 100 mg/L). The No Observed Effect Concentration (NOEC) was 100 mg/L.

Long-term toxicity to fish:

In the key study, Fathead minnows (Pimephales promelas) were exposed to N-butylpyrrolidone at mean measured concentrations of 10 to 167 mg/L under flow-through conditions for 33 days (a 5-day hatching period plus a 28-day post-hatch growth period) (OECD 210; EAG (Wildlife International, 2016). There were no statistically significant treatment-related effects on hatching success, survival or dry weight in any of the treatment groups. Growth, measured as total length and wet weight, was the most sensitive biological endpoint measured in this study. Fathead minnows exposed to N-butylpyrrolidone at a concentration of 167 mg/L had statistically significant reductions in total length and wet weight in comparison to the negative control. Consequently, the NOEC, based on growth, was 82 mg/L and the LOEC was 167 mg/L.

In a supporting study the chronic toxicity of test substance to Rare Minnow was investigated in a definitive test under semi-static conditions (24 h intervals) according to OECD Guideline 215. Juvenile fish in exponential growth phase were placed, after being weighed, in test chambers and exposed to a range of sublethal concentrations of the test substance dissolved in water (dechlorinated tap water). The test duration was 28 days. Effects on growth rates as well as abnormalities in morphology and behaviour were analyzed. All measured concentrations can be maintained within ± 20% of nominal concentrations, therefore, test results was described based on nominal concentrations. At the end of the test, no abnormal behaviors and mortalities were observed in blank control and the test groups (1.0 mg/L, 3.2 mg/L, 10 mg/L, 32 mg/L and 100 mg/L). At the end of the test, "pseudo" specific growth rate (mean ± standard deviation) of blank control and 1.0 mg/L,3.2 mg/L, 10 mg/L, 32 mg/L and 100 mg/L test groups were 1.66±0.59 (d-1), 1.60±0.30 (d-1), 1.67±0.30 (d-1), 1.63±0.40 (d-1), 1.54±0.40 (d-1) and 1.66±0.55 (d-1), respectively. The mean "pseudo" specific growth rate for each test concentration group were compared with blank control's using statistics method, there was not a significant difference (p>0.05). Hence, NOEC (28 d) on the growth of juvenile with Rare Minnow was 100 mg/L, and LOEC (28 d) was greater than 100 mg/L based on nominal concentration. No toxicological effects were observed at the highest test concentration (100 mg/L).

Acute toxicity to aquatic invertebrates:

In the key study the acute toxicity of N-Butylpyrrolidone towards Daphnia magna was investigated according to OECD Guideline No 202 and EU method C.2. At the beginning and at the end of the test, the content of the test item in the test solutions was determined using GC-determination. The main study was performed as limit test using 100 mg/L nominal concentration. Twenty daphnids were exposed to the test item for 48 hours in a static test system. After 24 and 48 hours, the immobilised daphnia were counted. The recovery after 48 hours was 94 % of the start concentration, the correlation between nominal and measured concentration was good. Therefore, the determination of the biological results was based on the nominal concentration. The following results were determined for the test item N-Butylpyrrolidone (species: Daphnia magna). 24h-NOEC >100 mg/L, 48h-NOEC >100 mg/L, 24h-EC50i > 100 mg/L, 48h-EC50i > 100 mg/L. The treatment showed no toxicity towards daphnids. None of the animals was immobilised in the control.

In a supporting study, the acute toxicity of N-Butylpyrrolidone towards Daphnia magna was investigated also according to OECD Guideline No 202. According to the test substance information provided by the sponsor, the “Acute Aquatic Toxicity Data” showed that the 48h-EC50 for the Daphnia acute immobilization was greater than 100 mg/L, a limit test was performed with a nominal concentration of 100 mg/L test group and a blank control containing no test substance. At the beginning and at the end of the test, the actual content of the test item in the test solutions and the blank control were measured by RRLC at the start (0 h) and end (48 h) of the test.

Four test vessels were filled with 50 mL volumes of test medium or 100 mg/L test substance solution in the 150 mL glass-beakers as the blank control groups or test substance groups, then young daphnids (5/vessel), aged less than 24 h at the start of the test, were exposed to 100 mg/L of the test substance for a period of 48 hours (they were placed into each test vessel to start the test) . Immobilisation was recorded at 24 h and 48 h and compared with control values. At the end of the test, the immobility of the nominal concentration of 100 mg/L test solution to Daphnia magna was 0%. The treatment showed no toxicity towards daphnids. None of the animals was immobilised in the control. Hence, the results for the 48 h median effective concentration (EC50), the highest concentration causing no immobility (EC0) and the lowest concentration producing 100 percent immobility (EC100) of test substance for Daphnia magna would be described based on nominal concentration. EC50 > 100 mg/L (nominal concentration); EC0 = 100 mg/L (nominal concentration); EC100 > 100 mg/L (nominal concentration).

Long-term toxicity to aquatic invertebrates:

A study was performed to assess the chronic toxicity of N-Butylpyrrolidone to Daphnia magna. The method followed was compatible with the OECD Guidelines for Testing of Chemicals (2012) No 211, "Daphnia magna Reproduction Test" referenced as Method C.20 of Commission Regulation (EC) No. 440/2008 and the US EPA Draft Ecological Effects Test Guidelines OCSPP 850.1300 "Daphnid Chronic Toxicity Test".

Based on data supplied by the Sponsor, Daphnia magna were exposed (10 replicates of a single daphnid per group) to an aqueous solution of the test item over a range of test concentrations of 1.0, 3.2, 10, 32 and 100 mg/L for a period of 21 days. The test solutions were renewed 3 times per week. The numbers of live and dead adult daphnia and young daphnids (live and dead) were determined daily. The daphnia were fed daily with a mixture of algal suspension and Tetramin® flake food suspension.

Results: Analysis of the 100 mg/L test preparation on Days 0, 5, 12 and 20 (fresh media) and on Days 2, 5, 7, 14 and 21 (old media) showed measured test concentrations to range from 80 % to 94 % of nominal value and so the results are based on nominal test concentrations only.

The 21-Day EC50 (immobilization) value, based on nominal test concentrations for the parental Daphnia generation (Pi) was estimated to be greater than 100 mg/L. The 21-Day EC50 (adult growth) based on nominal test concentrations was greater than 100 mg/L. The 21-Day EC50 (reproduction) based on nominal test concentrations was greater than 100 mg/L. The "Lowest Observed Effect Concentration" (LOEC) and the "No Observed Effect Concentration" (NOEC) based on nominal test concentrations were 100 mg/L and greater than 100 mg/L for parental immobilization, adult growth and reproduction, respectively. The "Maximum Acceptable Toxicant Concentration" (MATC) was calculated to be 100 mg/L.

Toxicity to algae:

A study was performed to assess the effect of N-Butylpyrrolidone on the growth of the green alga Pseudokirchneriella subcapitata. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (2006) No 201, "Freshwater Alga and Cyanobacteria, Growth Inhibition Test" referenced as Method C.3 of Commission Regulation (EC) No 761/2009.

Following a preliminary range-finding test, Pseudokirchneriella subcapitata was exposed to an aqueous solution of the test item at concentrations of 10, 20, 40, 80 and 160 mg/L (three replicate flasks per concentration) for 72 hours, under constant illumination and shaking at a temperature of 24 ± 1 °C. Analysis of the test preparations at 0 and 72 hours showed measured test concentrations to range from 92 % to 112 % of nominal and so the results are based on nominal test concentrations only.

Results: Inhibition of Growth rate (72 h): NOEC = 40 mg/L, LOEC = 80 mg/L, ErC10 = 110 mg/L, ErC50 >160 mg/L

Inhibition of Yield (72 h): NOEC = 40 mg/L, LOEC = 80 mg/L, EyC10 = 58 mg/L, EyC50 = 130 mg/L