Neodecanoic acid, iron salt

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Remarks:

Acute Toxicity to Daphnia magna

Type of information:

experimental study

Adequacy of study:

key study

Study period:

06 June 2017 to 13 November 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

The study was conducted in accordance with the requirements of OECD Chemicals Testing Guideline No. 202.

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Purity: 100%
Receipt Date: 06 March 2017
Expiry Date: 31 July 2019
Storage on Receipt: Refrigerated under nitrogen

Analytical monitoring:

yes

Remarks:

The Analytical Procedure, SMV 3201780-01V, used to confirm the concentration of test item in samples of test media during this test

Details on sampling:

Concentrations of the test item were determined by initially diluting the liquid sample 10:1 with tetrahydrofuran (THF). Following further dilution with diluent as required to bring the expected response within the calibration range, samples were analysed by injection onto a liquid chromatography time-of-flight mass spectrometry (LC-TOF/MS) system.

At the start of the test (0 hours), ca 10 mL samples of freshly prepared test media were taken from the control and 100% saturated solution for chemical analysis.

At 48 hours, ca 10 mL samples were also taken for chemical analysis from the pooled old test media from the control and 100% saturated solution test concentrations.

In each case duplicate samples were taken, one for chemical analysis and one as a ‘back-up’ should further analysis be required.

Vehicle:

no

Details on test solutions:

Based on the nature of the compound (mono-constituent with 100% purity) a saturated solution preparation method was considered most appropriate (based on OECD 23 guidance). However, solvent solubility was also assessed at 10 and 100 mg/mL, both were in solution, however, once the solvent stocks were spiked at 100µL/L into Elendt media the substance was no longer in solution. The 100 mg/mL stock would have given a final concentration of 10 mg/L.

The range-finding test was conducted at nominal test substance concentrations of 1.0, 10 and 100% saturated solution under static test conditions. A control group was also included. Duplicate test vessels were prepared for the control and each test concentration. Based on nominal concentrations, the results of the range-finding test suggested that there would be no effect at the top concentration of 100% saturated solution. Five juvenile daphnia (<24 hours old) were added to each test vessel.

No chemical analysis was performed for the range finding test.

Based on the results of the range-finding test, for which the key results only have been reported, the definitive limit test was conducted at a single test concentration of 100% saturated solution.

Test organisms (species):

Daphnia magna

Details on test organisms:

Juvenile Daphnia magna, less than 24 hours old, were taken from healthy parental laboratory cultures, held and maintained at the test facility. The culture was originally obtained from Microbiotest, Belgium.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

Not reported

Test temperature:

19.9–20.7 °C

pH:

8.16–8.51

Dissolved oxygen:

100–101

Salinity:

N/A

Conductivity:

N/A

Nominal and measured concentrations:

Single test concentration of 100% saturated solution.

Reference substance (positive control):

yes

Remarks:

See attached Annex 1 Summary of the Reference Test Results

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 7.44 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

100% saturated solution test

Basis for effect:

mortality

Remarks on result:

other: The 48 hour EC50 concentration is greater that the limit of solubility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

>= 7.44 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

100% saturated solution test

Basis for effect:

mortality

Remarks on result:

other: The 48 hour EC50 concentration is greater that the limit of solubility

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

>= 7.44 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

100% saturated solution test

Basis for effect:

mortality

Remarks on result:

other: The 48 hour EC50 concentration is greater that the limit of solubility

Details on results:

Throughout the results, numerical data may have been rounded for presentation purposes. Therefore, manual recalculation of the data may result in slightly different values to those shown.

Results with reference substance (positive control):

See attached Annex 1 Summary of the Reference Test Results

The results of the range-finding test are summarised below:

Nominal Cumulative immobilised Daphnia magna*

Nominal concentration	Cumulative immobilised Daphnia magna*
% saturated	24 hours		48 hours		% immobility
solution)	R1	R2	R1	R2	0
Control	0	0	0	0	0
1.0	0	0	0	0	0
10	0	0	0	0	0
100	0	0	0	0	0

*           Initial population of Daphnia magna: five per replicate

R           Replicate

Chemical analysis was not conducted during the range-finding test.

The results of the range-finding test suggested that toxicity would not be observed at the highest concentration of 100% saturated solution.

Solubility and Stability Trial

The results of the solubility and stability trial are summarised in the folowing table

Nominal	Measured Concentrations (mg/L)
Concentration (mg/L LR WAF)	0 hours (new)	48 hours (old)
100(a)	5.18	4.56
100(b)	13.4	14.3

Results showed the test substance was stable over the test period. It also showed variation between the duplicate media prepared, however, this is common when using a saturated solution preparation method without filtration as particulate can be easily syphoned in error.

Definitive Test Chemical Analysis

The results of the chemical analysis are presented in the attached Table 1.

Example chromatograms of test samples, standard solution and a typical calibration line are presented in in the attached Appendix 3.

The limit of quantification (LOQ) for the test item in Elendt M4 medium using this method was 0.3 µg/L.

Analysis of the test media samples was conducted at 0 (fresh media), and 48 hours (old media).

Chemical analysis of the 100% saturated solution test concentration at 0 hours (fresh media), showed a measured concentration of 7.44 mg/L and 48 hours (old media) gave concentration of 6.80 mg/L. Results were based on mean measured concentration, this was calculated to be 7.12 mg/L.

Water Quality

Water quality determinations for pH, temperature and dissolved oxygen (% ASV and mg/L) during the definitive test are presented in in the attached Table 2.

Test Media Descriptions

The test preparations were observed to be colourless solutions throughout the duration of the test.

Toxicity to Daphnia magna

The numbers of immobilised Daphnia magna at 24 and 48 hours, following exposure are presented in in the attached Table 3 and Table 4. The percentage immobility data is summarised below.

Cumulative immobilised Daphnia magna (initial population: 5 Daphnia per replicate)
Nominal concentration (%)	24 Hours					48 hours
saturated solution)	R1	R2	R3	R4	% Immobility	R1	R2	R3	R4	% Immobility
Control	0	0	0	0	0	0	0	0	0	0
100	0	0	0	0	0	0	0	0	0	0

R            Replicate

The¹EC50 values, the corresponding ²NOEC and ³LOEC values are presented in the following table.

Measured Concentrations (mg/L)
	24 Hour (mg/L)	48 Hour (mg/L)	Statistical Test
EC50	> 7.44	> 7.44	Derived Empirically
NOEC	= 7.44	= 7.44	Derived Empirically
LOEC	> 7.44	> 7.44	Derived Empirically

No significant toxicity was observed during the test. It was therefore considered that the results showed the test substance was not toxic to the test organisms at 100% saturated solution or 7.44 mg/L based on the initial measured concentration.

1 Concentration resulting in 50% immobility of exposed Daphnia magna

2 No observed effect concentration

3 Lowest observed effect concentration

The 48 hour EC50 concentration is therefore greater that the limit of solubility.

The validity criteria for control immobility (=10%) and dissolved oxygen (=3 mg/L) were both satisfied. The test is therefore considered valid.

Validity criteria fulfilled:

yes

Conclusions:

The 48-hour acute toxicity of the test item to the freshwater planktonic crustacean, Daphnia magna, was determined in accordance with the requirements of OECD Chemicals Testing Guideline No. 202 Daphnia sp. Acute Immobilisation Test (adopted April 13 2004).

The validity criteria for control immobility (=10%) and dissolved oxygen (=3 mg/L) were both satisfied. The test is therefore considered valid.

The initial concentration of the test substance was far lower than the nominal concentration. Nevertheless, the concentration remained within 20% of the initial over the test period, it can therefore be considered justifiable to base results on initial measured concentration.

Based on the initial measured concentration, the 48-hour EC50 value was determined to be >7.44 mg/L.

No effects were observed at the highest tested concentration, 7.44 mg/L based on initial measured concentration.

Executive summary:

The objective of the study was to determine the 48-hour acute toxicity of the test item against the mobility of the freshwater planktonic crustacean, Daphnia magna.

The study was conducted in accordance with the requirements of OECD Chemicals Testing Guideline No. 202.

Based on the results of a range-finding test, for which the key results only have been reported, a definitive limit test was conducted at a single concentration of 100% saturated solution. A control group was also included. The test was conducted under static test conditions with media preparation at 0 hours only.

At the start of the test, five juvenile D. magna were added to each of the four replicate test vessels for the control and test concentration. The D. magna in each test vessel were observed at 24 and 48 hours. The D. magna were not fed during the test.

 

Chemical analysis of the 100% saturated solution test concentration and control was conducted at 0 hours (fresh media) and 48 hours (old media).

 

Analysis of the test samples at 0 and 48 hours are summarised in the table below.

Nominal Concentration (%	Measured Concentration (mg/L)
Saturated solution)	0 hours (new)	48 hours (old)
Control	-	-
100	7.44	6.80

-          None found

 

 

Chemical analysis showed the test item was stable over the 48-hour test period. Therefore, results were based on initial measured concentration.

 

  

The (1)EC50 values, the corresponding (2)NOEC and (3)LOEC values are presented in the following table.

 

Measurd Concentrations (mg/L)
	24 Hour (mg/L)	48 Hour (mg/L)	Statistical Test
EC50	>7.44	>7.44	Derived Empirically
NOEC	= 7.44	= 7.44	Derived Empirically
LOEC	>7.44	>7.44	Derived Empirically

No effects were observed at the highest concentration tested.

(1) Concentration resulting in 50% immobility of exposed Daphnia magna

2 No observed effect concentration

3 Lowest observed effect concentration

 

As no immobility was observed during the test statistical analysis was not required. Therefore, results were derived empirically.

The validity criteria for control immobility (=10%) and dissolved oxygen (=3 mg/L) were both satisfied. The test is therefore considered valid.

Description of key information

The 48-hour acute toxicity of the test item to the freshwater planktonic crustacean, Daphnia magna, was determined in accordance with the requirements of OECD Chemicals Testing Guideline No. 202 Daphnia sp. Acute Immobilisation Test (adopted April 13 2004).

Based on the initial measured concentration, the 48-hour EC50 value was determined to be > 7.44 mg/L. The concentration represents 100 % saturated solution.

No effects were observed at the highest tested concentration, 7.44 mg/L based on initial measured concentration.