Reaction mass of N-(hydroxymethyl)hexadecan-1-amide and N-(hydroxymethyl)stearamide

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29.11.-03.12.2018.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Version / remarks:

2006

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of N-(hydroxymethyl)hexadecan-1-amide and N-(hydroxymethyl)stearamide

EC Number:

911-553-0

Molecular formula:

not applicable

IUPAC Name:

Reaction mass of N-(hydroxymethyl)hexadecan-1-amide and N-(hydroxymethyl)stearamide

Test material form:

solid: particulate/powder

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name:
- Strain: 86.81
- Source (laboratory, culture collection): MBM Sciencebridge GmbH (Institut für Pflanzenphysiologie of Universität Göttingen)
- Age of inoculum (at test initiation):
- Method of cultivation:

ACCLIMATION
- Acclimation period:
- Culturing media and conditions (same as test or not):
- Any deformed or abnormal cells observed:

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

21.1 – 22.2 °C

pH:

7.5-7.7

Nominal and measured concentrations:

100 / 32 / 10 / 3.2 / 1 mg/L (nominal)

Details on test conditions:

TEST SYSTEM
- Test vessel: glass flasks
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: glass flask, 65mL total volume, 45 ±1 mL test solution and algae
- Aeration:
- Type of flow-through (e.g. peristaltic or proportional diluter): -
- Renewal rate of test solution (frequency/flow rate):-
- Initial cells density: 2.2E3 cells/mL
- Control end cells density: 3.1E6 cells/mL
- No. of organisms per vessel:
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- No. of vessels per vehicle control (replicates):

GROWTH MEDIUM
- Standard medium used: yes
- Detailed composition if non-standard medium was used:

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
- Total organic carbon:
- Particulate matter:
- Metals:
- Pesticides:
- Chlorine:
- Alkalinity:
- Ca/mg ratio:
- Conductivity:
- Culture medium different from test medium:
- Intervals of water quality measurement:

OTHER TEST CONDITIONS
- Sterile test conditions: yes/no
- Adjustment of pH:
- Photoperiod:
- Light intensity and quality: 5000 lx
- Salinity (for marine algae):

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter]
- Chlorophyll measurement:
- Other:

TEST CONCENTRATIONS
- Spacing factor for test concentrations:
- Justification for using less concentrations than requested by guideline:
- Range finding study
- Test concentrations:
- Results used to determine the conditions for the definitive study:

Reference substance (positive control):

yes

Remarks:

Potassium dichromate (K2Cr2O7, CAS No. 7778-50-9)

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Remarks on result:

not determinable

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Executive summary:

One valid experiment was performed.

The study was performed using 5 concentrations ranging from 1.0 to 100 mg/L (nominal).Incubation time (test system Desmodesmus subspicatus) was 72 hours. The cell concentration of each replicate was determined by measuring the cell numbers every 24 hours with an electronic particle counter. Growth rate µ and the yield[1]were determined from the cell number at the respective observation times.

Statistically significant inhibition of algal growth was observed only at the highest tested concentration of 100 mg/L for the endpoint growth rate.

At the start and at the end of the test, the content of the test item in the test solutions was estimated by determination of the dissolved organic carbon (DOC) content in the test solutions using a carbon analyser. Because of the very poor solubility of the test item, all measured DOC values are in the same very low range as the blank value.Nevertheless, it can be demonstrated that the test item was present in the test solutions because algae growth was inhibited at the highest test concentration. Therefore, the biological results were based on the nominal concentrations.

The 72h-EC₅₀values of potassium dichromate (K₂Cr₂O₇, CAS No. 7778-50-9) were determined in a separate reference test. The values lay within the range of the laboratory (growth rate 0.73 - 1.10 mg/L, yield 0.21 – 0.66 mg/L).

The following results for the test itemN-(hydroxymethyl) stearamidewere determined:

Table 3‑a         Results of the test item

Endpoint	NOEC	LOEC	EC10	EC50
Growth Rate	32 mg/L	100 mg/L	> 100 mg/L	> 100 mg/L
Yield	≥100 mg/L	> 100 mg/L	44.6 mg/L	> 100 mg/L

[1]Yield (according to OECD Guideline 201) is defined as the biomass at the end of the exposure period minus the biomass at the start of the exposure period. Calculation see under 8.2 Growth and growth inhibition are quantified from measurements of the algal biomass as a function of time. Algal biomass is defined as the dry weight per volume, e.g. mg algae/L test solution. However, dry weight is difficult to measure and therefore surrogate parameters are used. Of these surrogates, cell counts are most often used.