N-[3-(dimethylamino)propyl]oleamide

Endpoint summary

Additional information

For justification of read-across please see separate document attached to section 13 of the IU5 dossier.

Short-term toxicity to fish:
The test substance was tested in an acute toxicity test with Brachydanio rerio (zebra fish) under semi-static conditions in accordance with EEC method C.1 and OECD Guideline 203. Zebra fish were exposed to 0.1, 0.18, 0.32, 0.58 and 1.05 mg test item/L. No chemical analysis of the test concentrations were performed during the test and all concentrations mentioned are nominal concentrations. The LC50 (96h) was calculated to be 0.22 mg/L with 95% confidence limits of 0.19 and 0.26 mg/L. The highest concentration causing no mortality (no observed effect concentration, NOEC) after 96 hours amounted to 0.10 mg/L, whereas 100% mortality was produced within 30 hours at 0.32 mg/L. At the concentrations of 0.32, 0.58 and 1.05 mg/L the fish showed reduced activity before their death.

Short-term toxicity to aquatic invertebrates:
A toxicity study on aquatic invertebrates with N-[3-(Dimethylamino)propyl]oleamide is not available. Consequently, read-across was applied using a characteristically similar compound, N-[3 -(dimethylamino)propyl].
The acute toxicity of the test item to Daphnia magna was assessed according to the method C2 of the European Directive 92/69/CEE and the guideline 202 (part I) of the OECD. Daphnia were exposed in a static test to 0.016, 0.031, 0.063, 0.125, 0.25, 0.5 and 1 mg test item /L.The test was performed with 5 Daphnia per vessel. Testing flasks were incubated in darkness at 19.2± 0.5 °C for 48 hours. For each exposure concentration, the percentage of immobilisation after 24 hours and 48 hours was recorded. As no analytical method was available, effective concentrations have been calculated using the initial nominal concentrations of the test substance. The calculated EC50 after 24 hours and 48 hours were 0.58 (95% CI: 0.38 -1.1) mg/L and 0.28 (95% CL: not determined) mg/L respectively. The appearance of the test solutions was visually checked at the beginning and at the end of the test. Solutions were found to be clear over the period of the test. No precipitation was observed at the end of the test.

Long-term toxicity to aquatic invertebrates:
A reproduction study on aquatic invertebrates with N-[3-(Dimethylamino)propyl]oleamide is not available. Consequently, read-across was applied using a characteristically similar compound, N-[3 -(dimethylamino)propyl].
In oder to assess the toxicity of the test substance in an aquatic environment, a Daphnia magna reproduction test under semi static conditions was conducted in accordance with OECD Guideline No. 211 and EU method C.20. Some modifications to the guideline were applied. The test was carried out according to the bulk approach using enriched natural surface water with a low Dissolved Organic Carbon (DOC) and Total Suspended Solids (TSS) content, allowing a more environmentally realistic determination of the effects of the test chemical to be made.
Young Daphnia, aged less than 24 hours, were exposed to the nominal concentrations of 0.004, 0.015, 0.048, 0.15 and 0.5 mg test item/L over a time period of 21 days. Primary test criterion of toxicity used was reproductive capacity, expressed as the total number of neonates per adult daphnid alive at the end of the test. Other endpoints based on adult mortality, length and weight were calculated if possible.
Analytical determinations of the test solutions showed that approximately 80% of the concentrations could be detected in the stock solution and in the highest 3 concentrations. The recovery in the lower concentrations fell below 80%. Loss of the chemical at lower concentrations was considered a characteristic of the test chemical as was accepted as part of the bulk approach. It was concluded that the test organisms were fully exposed to the test chemical in keeping with the bulk approach and the nominal concentrations were used for calculations of the effect levels.
Based on the reproduction and length data of the surviving daphnia a toxic effect can be determined. The NOEC value and LOEC value, based on reproduction and adult length were 0.048 mg/L and 0.15 mg/L respectively. The EC10 based on reproduction was calculated as 0.07 mg/L confidence limits could not be calculated. The EC10 based on length was calculated as 0.14 mg/L confidence limits could not be calculated. The dry weight endpoints was considered unreliable due to the inaccuracy involved in weighing the low number of surviving daphnids. The adult mortality endpoint was not considered reliable due to physical effects being the most likely cause of the effects.

Toxicity to aquatic algae and cyanobacteria:
A toxicity study on aquatic algae with N-[3-(Dimethyl lamino)propyl]oleamide is not available. Consequently, read-across was applied using a characteristically similar compound.
The chronic toxicity of the test item to fresh-water green algae Pseudokirchneriella subcapitata was determined according to the method C.3 of the Directive 92/69/EEC of the European Commission, which is in conformity with the OECD Guideline 201. Algae were exposed to a range of concentrations of the test item dissolved in dilution water. The toxic effect measured during the assay was the inhibition of cellular multiplication over a time period of 72 hours. The study was performed using 100 mL glass erlenmeyer flasks stoppered bungs of cellulose, containing 50 mL of test solution inoculated with an algal suspension so that the initial cell concentration was equal to 1 x 10^4 cells/mL. Test flasks were incubated at 23 ± 1 °C continuously shaken and constantly illuminated. The cell density was measured daily. Analytical chemistry and physico-chemical measurements were carried out at the beginning and the end of the test. After 72 hours an EC50 value of 0.003 mg/L based on cell growth and 0.005 mg/L based on growth rate was determined. The NOEC was 0.002 and 0.003 mg/L based on cell growth and growth rate, respectively. The very low EC50 values may be related to a true algicidal effect of the test item. Effective concentrations and NOEC have been calculated using the geometric average values between initial and final concentrations of the test substance. Concentrations were measured by liquid chromatography coupled with mass spectrometry. Initial and final concentrations were not equivalent to nominal concentrations.

Toxicity to microorganisms:
In an activated sludge respiration inhibition test the influence of the test item on the activated sludge by measuring the respiration rate was evaluated according to OECD guideline 209, corresponding to EU C.11. Four experiments were carried out. Activated sludge from a domestic sewage treatment plant was used as inoculum in all tests. 3,5-Dichlorophenole was used as reference item in the experiments.
Fist, a limit-test using the nominal concentration 1000 mg/L was performed. After three hours a mean respiration inhibition of 90% of the activated sludge was determined. Next, a pre-test was performed likewise using three concentrations ranging from 1 to 100 mg/L. The treatments showed no inhibition compared with the controls. Then a main study was performed using five concentrations in duplicate, ranging from 1000 to 100 mg/L (nominal). The dry matter of the activated sludge was determined as 3.88 g suspended solids/L, giving a concentration of 1.54 g suspended solids/L in the test. The test item showed concentration-related inhibition of the activated sludge down to a concentration of 320 mg/L, no inhibition was found in the treatments containing 180 mg/L. In one replicate of the treatment 100 mg/L, though, an inhibition value of 21% was determined, which was believed to be an outlier. Therefore, a verification experiment was performed, using the concentration 100 mg/L only. The dry matter of the activated sludge was determined as 4.18 g suspended solids/L, giving a concentration of 1.67 g suspended solids/L in the test. The test item showed no inhibition at the tested concentration; therefore, the measured value in the main study had been an outlier. The following results for the test item were calculated using the inhibition values which were found in the main study (excluding the outlier):
3 h NOEC = 180 mg/L
3 h EC20 = 280 mg//L (95% confid. interv.: 200 - 350 mg/L)
3 h EC50 = 480 mg/L (95% confid. interv.: 400 - 600 mg/L)