(Z)-N-octadec-9-enylhexadecan-1-amide

Endpoint summary

Additional information

Terrestrial data of octadec-9-enylhexadecan-1-amide (oleyl palmitamide, CAS 16260-09-6) are available for three trophic levels. All studies were performed according to international guidelines and GLP.

One experimental study is available investigating the toxicological effects of the test item (CAS 16260-09-6) to earthworms (ECT, 2017). The study was performed according to OECD guideline 222. Adult Eisenia andrei (4 x 10 animals per concentration, the fresh weight was between 250 and 600 mg) were exposed for 28 days in an artificial soil to the nominal concentrations of 62.5, 125, 250, 500 and 1000 mg test item/kg artificial soil dry weight. The artificial soil comprised 5% sphagnum peat, 20% kaolin clay, 74–75% Quartz sand and 0.3 - 1% calcium carbonate. No morphological and behavioral effects were observed. Related to weight alterations and symptoms, the no-observed-effect-concentration (NOEC) was ≥ 1000 mg test item/kg dry weight soil, the lowest-observed-effect-concentration (LOEC) > 1000 mg test item/kg dry weight soil for all parameters after 28 days for mortality and biomass. No mortality was recorded resulting in a EC50 (28 d) of > 1000 mg test item/kg dry weight soil. For reproduction the no observed effect concentration (NOEC) was observed at ≥ 1000 mg test item/kg dry weight soil and the EC50 at > 1000 mg test item/kg dry weight soil after 56 days.

No experimental data on the toxicity of (Z)-N-octadec-9-enylhexadecan-1-amide (oleyl palmitamide, CAS 16260-09-6) to terrestrial arthropods are available. The substance is characterised by a high log Koc (log Koc > 5) indicating a considerable potential for adsorption to the soil particles but as the substance is highly insoluble in water (< 0.01 mg/L), only low concentrations are expected in the pore water. Therefore, tests with soil-dwelling organisms like earthworm, which allow potential uptake via surface contact, soil particle ingestion and porewater (ECHA, 2012), are most relevant for the evaluation of soil toxicity. In addition, in the absence of a clear indication of selective toxicity, an invertebrate (earthworm or collembolan) test is preferred, as outlined in ECHA guidance section R.7.11.5.3, page 122. Thus, it can be assumed that earthworms would be highly exposed to toxicants in soil and hence are most sensitive to the potential adverse effects of the substance.

One experimental study is available investigating the potential effects of the test item (CAS 16260-09-6) on seedling emergence and growth (ECT, 2017) of plants. The studies were performed according to OECD guideline 208 under GLP conditions. For this study six species of non-target terrestrial plants (2 monocots and 4 dicots) were planted in a natural sandy loam soil (standard soil LUFA Sp 2.3) immediately after test item application. Five test item concentrations were tested with each species: 10, 31.6, 100, 316 and 1000 mg test item /kg soil dw. Plants were left to grow under controlled conditions for a period of 14 to 21 days following seedling emergence of at least 50% in the control. Test item concentrations were applied within artificial soil. The control soil received sand which had not been treated with the test item. Soils were supplied with water and a nutrient solution as needed by bottom watering. The test was performed in growth chambers equipped with artificial lighting (201 to 352 μE m-2 s-1, for 16 hours per day) and air conditioning (mean air temperature ranging from 17.1 to 26.4 °C, relative humidity ranging from 17.0% to 58.1%). The pots were randomly placed at the beginning of the test and were re-arranged at minimum weekly intervals. On day 7 and day 14 (or day 17 for A. cepa) after 50% emergence of control, seedlings were evaluated visually. At the end of the test, seedlings were counted, evaluated visually, and harvested to determine shoot fresh weight. At concentrations up to and including 1000 mg/kg soil dry weight the test item had no statistically significant adverse effect on either seedling emergence, seedling survival or shoot fresh weight of any of the six test species. Shoot fresh weight of the test species Solanum lycopersicum in the second test run was reduced at concentrations of ≥ 100 mg/kg soil dry weight (P<0.05). Therefore the lowest LOEC (lowest observed effect concentration) and NOEC (no observed effect concentration) were determined to be 316 mg/kg soil dw and 100 mg/kg soil dw, respectively. Due to the lack of either adverse effects or a concentration response relationship effective concentrations could not be calculated and are assumed to be higher than 1000 mg/kg dw except for shoot fresh weight of S. lycopersicum (second test run). For S. lycopersicum the EC10 and EC25 were calculated to be 78.5 mg/kg soil dry weight and 745 mg/kg soil dry weight, respectively, while the EC50 was >1000 mg/kg soil dry weight under the conditions of this test.

One experimental study is available investigating the potential effects of the test item (CAS 16260-09-6) on nitrogen transformation (ECT, 2017) of terrestrial microorganisms.The study was performed according to OECD guideline 216 under GLP conditions. Test item was ground with fine quartz sand using a pestle and mortar prior to being mixed together with the sand into the test soil (Lufa standard soil type 2.3). The soil test was amended with ground lucerne grass green meal (5.0 g/kg soil). Test item was tested at five concentrations ranging from 260 mg/kg soil dry weight (T1) to 1000 mg/kg soil dry weight (T5) against an untreated control (C) with four replicates, each. Nitrate of the soil was measured after test item application on day 0, and 28 days after test item application. Due to the lack of a dose-response relationship, effective concentrations could not be calculated. However, based on the maximum effect of 16.7% observed at the highest tested concentration, the EC50 and EC25 can be considered to be greater than 1000 mg/kg soil dry weight, which was the highest tested test item concentration.