N-(2-hydroxypropyl)oleamide

Toxicity to soil microorganisms

Administrative data

Endpoint:

toxicity to soil microorganisms

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From November 03, 2016 to December 06, 2016.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 216 (Soil Microorganisms: Nitrogen Transformation Test)

Deviations:

yes

Remarks:

Two deviations were observed during this study. The deviations are not critical and have no influence on the results of this study.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

N-(2-hydroxypropyl) Oleamide

Cas Number:

111-05-7

IUPAC Name:

N-(2-hydroxypropyl) Oleamide

Test material form:

solid

Remarks:

Beige waxy solid

Sampling and analysis

Analytical monitoring:

not required

Test substrate

Vehicle:

yes

Details on preparation and application of test substrate:

The test item “N-(2-HYDROXYPROPYL) OLEAMIDE” is dispersible in water and the deionized water was used as the carrier. The test item was directly added in the testing solutions and mixed with the soil in order to improve the homogeneity and also to increase the bioavailability of the test item in soil for the microorganisms.

Test organisms

Test organisms (inoculum):

soil

Study design

Total exposure duration:

28 d

Test conditions

Test temperature:

20+/- 2°C

Moisture:

The moisture content of the samples was checked and adjusted two or three times a week in order to maintain the moisture content of soil within 40 - 60 ± 5 % of Water Holding Capacity (WHC).
In order to respect the recommendation, the moisture content of soil samples was calculated for the lower and the highest WHC interval:
0.3482*0.40*100 = 13.9% for 40% WHC
0.3482*0.60*100 = 20.9 % for 60% WHC
During the period of incubation (28 days), the moisture contents of soil samples were well within 13.9 % and 20.9% which corresponds to 40 to 60% WHC and were compliant to the guideline OECD 216.

Nominal and measured concentrations:

As the test item was non agrochemicals, five concentrations were tested according the preliminary test, non GLP and in agreement with the sponsor, the nominal concentrations were as follow: 500 – 1050 – 2200 – 4630 – 9720 mg test item / kg dry soil.

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

>= 9 720 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

nitrate formation rate

Details on results:

On day 0, nitrate contents were similar to the Control group and for the treated groups. The soil LUFA 2.3 contains nitrate and the repartition between the Control group and for the treated groups was homogeneous.

After 14 days of incubation period, the formed nitrate content increased in the control group and in the first two treated groups and two phenomena were observed:
- A strong stimulation was observed on both nominal concentration of 500 and 1050 mg/Kg soil dry weight in comparison to the control,
- A strong inhibition was recorded on both concentrations 4630 and 9720 mg/Kg soil dw and the inhibition rates were respectively - 59.9 % and - 87.1%

After 28 days of incubation, the micro-organisms responsible of the formation of nitrate were not affected at any tested concentration. A strong stimulation was observed in all tested concentrations with formed nitrate contents very high in comparison to the control.

Reported statistics and error estimates:

The formed NO3-N in each treatment was compared with NO3-N in the control. A dose-response curve versus time was prepared. Statistical evaluation of the test results was performed with an ANOVA analysis at 5% significant level (Minitab 17, statistical software) and a NOEC was determined but no LOEC. The results did not permit to calculate a regression in order to determine an estimation of the ECx values

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

All the validity criteria were successful.
No adverse effects of the test item “N-(2-HYDROXYPROPYL) OLEAMIDE” on nitrogen transformation in soil was observed at any tested concentration (500, 1050, 2000, 4630 and 9720 mg/Kg soil dry weight) after 28 days of incubation. A NOEC value was determined as follows: NOEC = 9720 mg/Kg soil dry weight.

Executive summary:

The aim of this study was to investigate long term potential effects after a single exposure of the test item “ N-(2-HYDROXYPROPYL) OLEAMIDE” on Nitrogen transformation activity of soils microorganisms according to the OECD 216 guideline (January 21, 2000).

Sieved soil was amended with powdered Lucerne meal and either treated with the test item or left untreated (Control). As the test item was non agrochemicals, five concentrations were tested according the preliminary test, non GLP and in agreement with the sponsor, the concentrations were as follow: 500 – 1050 – 2200 – 4630 – 9720 mg test item / kg dry soil.

The untreated (control) and treated (500 – 1050 – 2200 – 4630 – 9720 mg/Kg soil dry weight) samples were incubated in the dark at 20+/- 2°C. The moisture content of the samples was checked and adjusted two or three times a week. NO3-N content was determined in the control and treated soils at 0, 14 and 28 days after treatment by ionic chromatography.

No significant decreases in the nitrogen transformation were found for any concentration of the test item at the end of the 28 days incubation period in comparison to the control. A NOEC value was determined as follows: NOEC = 9720 mg/Kg soil dry weight.