Oleonitrile

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-04-26 to 2010-05-31

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study, GLP, All validity criteria fulfilled, complete identification of test substance, including chemical analyses

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Oleonitrile

EC Number:

204-016-0

EC Name:

Oleonitrile

Cas Number:

112-91-4

Molecular formula:

C18H33N

IUPAC Name:

(9Z)-octadec-9-enenitrile

Details on test material:

- Name of test material (as cited in study report): Oleylnitrile (CAS No. 112-91-4)
- Physical state: Liquid, light yellow
- Composition of test material, percentage of components: 101.1 % (w/w), active content nitriles
- Purity test date: 2009-09-21
- Lot/batch No.: S001149
- Expiration date of the lot/batch: 2018-01-30
- Storage condition of test material: Room temperature, protected from moisture and light

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: All loading levels and the control were analytically verified in the fresh media (0 and 24 h) by GC-MS.
- Sampling method: For the fresh media, samples of the freshly prepared test solutions were taken and analysed. The old media were analytically verified at two loading levels 0.100 and 1.00 mg/L and the control, respectively. For the old media samples, additional replicates were prepared without test organisms and incubated under test conditions until analysis.
The sorption of the test item to the glassware was quantified once during the test period after the first sampling interval. Therefore, one test vessel of the test concentration 1.00 mg/L, containing daphnids, was emptied after 24 h of exposure and rinsed twice with demineralised water. Thereafter an extraction of the test vessel was carried out.
- Sample storage conditions before analysis: All samples were stored at 6 ± 2 °C until start of analysis, if necessary. The prepared samples were stored on the autosampler until measuring.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A water soluble fraction (WSF) with a nominal loading of 10 mg/L was prepared with dilution water two days prior to application (0 h) and water renewal (after 24 h). The WSF will be shaken with 20 rpm for 24 h at room temperature. After a separation phase of at least 24 h the WSF was taken from the homogeneous liquid phase. There will be no filtration applied to prepare the WSF.
- Eluate: Natural River Water
- Differential loading: 0.032 - 0.100 - 0.320 - 1.00 - 3.20 - 10.0 mg/L
- Controls: Four replicates of dilution water without test item tested under the same conditions as the test groups

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna (STRAUS)
- Strain: Clone 5
- Source: Institut für Wasser-, Boden- Lufthygiene (WaBoLu), further own breeding
- Age at study initiation (mean and range, SD): 2 to 24 h
- Method of breeding: In 2-3 L glass vessels with appr. 1.8 L culture medium, at 20 +/- 2 °C, in an incubator, 16 h illumination, illumination strength max. 20 µExm-2 x s-1
- Feeding during test: No feeding

ACCLIMATION
- Acclimation period: 2 h
- Acclimation conditions (same as test or not): Same as test
- Type and amount of food: No feeding
- Health during acclimation (any mortality observed): Healthy, no mortality observed

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

No

Test conditions

Hardness:

Natural river water: 92 and 83 (mg CaCO3/L)

Test temperature:

19.2 and 19.0 °C

pH:

Water Parameters at 24 h (Old Media)
(measured in all replicates)
Oleylnitrile
Nominal Loading
Level of the Water Soluble Fraction (WSF)
[mg/L] pH-Values
Replicates
1 2 3 4
10.0 7.69 7.74 7.75 7.68
3.2 7.65 7.62 7.62 7.60
1.0 7.61 7.60 7.59 7.59
0.32 7.65 7.55 7.61 7.61
0.1 7.67 7.70 7.68 7.64
0.032 7.63 7.63 7.60 7.75
Control 7.68 7.68 7.63 7.56

Water Parameters at 48 h (Old Media)
(measured in all replicates)
Oleylnitrile
Nominal Loading
Level of the Water Soluble Fraction (WSF)
[mg/L] pH-Values
Replicates
1 2 3 4
10.0 7.75 7.78 7.73 7.87
3.2 7.73 7.74 7.76 7.77
1.0 7.65 7.72 7.71 7.69
0.32 7.67 7.53 7.55 7.65
0.1 7.81 7.59 7.67 7.63
0.032 7.73 7.72 7.70 7.62
Control 7.66 7.72 7.71 7.73

Dissolved oxygen:

Oleylnitrile
Nominal Loading
Level of the Water Soluble Fraction (WSF)
[mg/L] Dissolved O2 -Concentration [mg/L]
Replicates
1 2 3 4
10.0 8.33 8.52 8.46 8.48
3.2 8.45 8.24 8.28 8.26
1.0 8.44 8.39 8.35 8.29
0.32 8.56 8.47 8.48 8.42
0.1 8.67 8.65 8.63 8.69
0.032 8.73 8.72 8.71 8.61
Control 8.67 8.68 8.74 8.75

Water Parameters at 48 h (Old Media)
(measured in all replicates)
Oleylnitrile
Nominal Loading
Level of the Water Soluble Fraction (WSF)
[mg/L] Dissolved O2 -Concentration [mg/L]
Replicates
1 2 3 4
10.0 8.42 8.43 8.42 8.39
3.2 8.52 8.58 8.58 8.49
1.0 8.54 8.50 8.57 8.55
0.32 8.48 8.42 8.56 8.53
0.1 8.51 8.44 8.52 8.31
0.032 8.62 8.60 8.52 8.61
Control 8.85 8.76 8.75 8.73

Salinity:

Freshwater

Nominal and measured concentrations:

Please refer to "Any other information on materials and methods"

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers, 50 mL
- Type (delete if not applicable): closed with parafilm
- Material, size, headspace, fill volume: Glass beakers (4 cm ID x 7 cm H), 50 mL
- Aeration: No
- Renewal rate of test solution (frequency/flow rate): One application at test start, static test
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates): None


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
Natural river water of the river Leine was used. Specifications of the natural river are presented in the table below. The natural river water was filtered with a membrane filter (0.45 µm, RC, MACHEREY-NAGEL) prior to use in the test.

River: Leine
Location Marienbergstraße,
D-31171 Nordstemmen, Germany
(52° 10’ 14.98‘’, 9° 46’ 7.64’’)
Sampling Date 2009-12-15
Weather on Day of Sampling Cloudy, ca. -1 °C
Colour yellowish, clear
pH 7.97
Conductivity [µS/cm] 386
Dissolved Oxygen [mg O2/L] 8.62
DOC [mg C/L] 3.9
TOC [mg C/L] 3.9
Ammonium-N [mg N/L] 0.042
Nitrate-N [mg N/L] 2.62
Total Nitrogen [mg N/L] 3.53
o-Phosphate-p [mg P/L] 0.062
Total Phosphate [mg P/L] 0.053
Suspended Matter [mg/L] 16.2
Total Hardness [mg CO3/L] 154
Storage conditions 6 ± 2 °C

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16:8 light:dark cycle
- Light intensity: Diffuse light, illumination strength max. 20 µE x m-2 x s-1


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :


TEST CONCENTRATIONS
- Range finding study
Immobilization Rates of the Preliminary Range Finding Test
(n = 20, divided into 2 replicates with 10 daphnids each)
Oleylnitrile
Nominal
Loading Level of the WSF*
[mg/L] IMMOBILIZATION [%]
24 h 48 h
Replicates Replicates
1 2 MV 1 2 MV
10 100 100 100 100 100 100
1 80 90 85 100 100 100
0.1 50 60 55 80 80 80
Control 0 0 0 0 0 0

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.03 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: (0.0262-0.0348)

Details on results:

- Behavioural abnormalities: None
- Mortality of control: 0%
- Other adverse effects control: None
- Abnormal responses: None
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: None

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- EC50/LC50: 1.70 (CI 1.51 - 1.97) mg/L

Reported statistics and error estimates:

The EC50-values for the reference test and for the definitive test after 48 h were calculated by using sigmoidal dose-response regression. The confidence intervals for both EC50-values were calculated from the best-fit values, the standard error and the t-distribution with the software GraphPad prism.
The EC50-value for the definitive test after 24 h was deduced directly from the observation data without mathematical calculation. The concentration effect relationships are presented graphically.

Any other information on results incl. tables

Immobilization Rates of the Definitive Testafter 24 and 48 hours of Exposure

                 (n = 20, divided into 4 replicates with 5 daphnids each)

Oleylnitrile		IMMOBILIZATION [%]
Nominal Loading Level of the Water Soluble Fraction (WSF) [mg/L]	Geometric Mean Initially Measured Concentrations [mg/L]	24 h					48 h
		Replicates					Replicates
		1.	2.	3.	4.	MV	1.	2.	3.	4.	MV
10.0	5.91	60	40	100	100	75	100	100	100	100	100
3.20	1.90	60	80	100	60	75	100	100	100	100	100
1.00	0.542	60	20	60	60	50	100	100	100	100	100
0.320	0.155	60	60	40	20	45	100	100	100	100	100
0.010	0.0569	40	40	60	20	40	100	80	80	100	90
0.032	0.0160	0	20	0	20	10	0	20	0	20	10
Control		0	0	0	0	0	0	0	0	0	0

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In this study the test item Oleylnitrile was found to be toxic to Daphnia magna after 48 h at concentrations of the test item of 0.0569 mg/L (LOEC48 h) and higher.
Based on the geometric mean of the initially measured test item concentrations the 48-hour EC50 for Daphnia magna was calculated to be 0.0302 mg/L (95 % confidence limits: 0.0262 – 0.0348 mg/L).
The NOEC after 48 h was determined to be 0.0160 mg/L as the highest tested concentration level with no biologically significant effect (Immobilization rates of  10 % are considered to be not significant according to the guideline).

The concentrations of Oleylnitrile (CAS No. 112-91-4) were analysed at all concentration levels from freshly prepared media and at 2 concentration levels from old media (24 h and 48 h) via GC-MS analysis. The samples of the fresh media (0 and 24 h) showed recoveries in the range of 44 to 62 % of the nominal values. The recoveries in the old media (after 24 and 48 h) were in the range of 34 to 66 % of the nominal values. Adsorption of the test item to the glassware was checked after an exposure period of 24 h at a test item concentration of 1.00 mg/L. The observed concentration after applying the concentration procedure (s. Preparation of Adsorption sample) was determined to be below LOQS showing that less than 5.7 % of the observed initial geometric mean concentration of 0.542 mg/L was sorbed to glassware.
All effect values are therefore given based on the geometric mean of the initially measured concentrations of the test item in the fresh media (0 and 24 h), calculated to be: 0.0160 – 0.0569 – 0.155 – 0.542 – 1.90 – 5.91 mg/L. The mean recovery rates were in the range of 48 to 59 %.

Executive summary:

In the acute immobilization test with Daphnia magna (STRAUS) the effects of the test item Oleylnitrile (CAS No. 112-91-4, batch number: S001149) were determined according to OECD 202 (2004) from 2010-04-26 to 2010-05-31, with the definitive exposure phase from 2010-05-19 to 2010-05-21, at Dr.U.Noack-Laboratorien, Käthe-Paulus-Str. 1, D-31157 Sarstedt, Germany .

The study was conducted with natural river water under semi-static conditions with a water soluble fraction (WSF) with a nominal loading of 10 mg/L and further 5 dilution levels, with nominal loadings in the range of 0.032 to 3.2 mg/L, set up in a geometric series with a dilution factor of √10, over a period of 48 h. 20 test organisms were exposed to each test concentration and control.

Oleylnitrile (CAS No. 112-91-4) is insoluble in water and also has a strong tendency to adsorb to suspended matter, algae and test vessels or organic material (including dissolved organic matter such as humic acids). Many poorly soluble substances in general but long chain nitriles in particular rank among the most difficult substances to test in environmental toxicology. Standard guideline studies are inappropriate to test substances with such properties and the current REACH Guidance Documents do not provide sufficient guidance concerning bioavailability and exposure assessment for difficult substances like the nitriles as these were written with normal hydrophobic chemicals in mind, failing to take into account the lack of bioavailability that occurs in the environment with these substances.

The aquatic ecotoxicity tests with nitriles were therefore performed in river water to allow a PEC_aquatic,bulk/PNEC_aquatic,bulkapproach and is considered to be conservative but more environmentally realistic than the standard method. This approach is based on PEC estimations representing ‘total aquatic concentrations’. To characterize the risk to the aquatic compartment the PEC_aquatic,bulk is compared with the PNEC_aquatic,bulk derived from river water ecotoxicity studies (ECETOC, 2001).

In order to class a standard laboratory toxicity study valid, it is of particular importance that - besides information on test substance, test method / conditions and test organism used - suitable precautions are taken to prevent the loss of test substance by adsorption and that exposure concentrations are based upon measured levels.

For ecotoxicity tests performed using the bulk approach, however, adsorption to suspended matter and DOC is acceptable and only adsorption to glassware should be accounted for. For a valid bulk approach test the concentration-effect relationship should be based on the sum of adsorbed and dissolved substance in the volume of the medium tested. One of the advantages of the bulk approach tests with these difficult substances is that in the presence of suspended matter, humic acids and/or algae, the residual sorption to glassware will be negligible. The results of these bulk approach tests are therefore much easier to interpret, more environmental realistic, and if compared to PEC_bulk clearly provide a more appropriate assessment of risks for the environment.

Nominal loadings of the test item Oleylnitrile were selected after a non GLP preliminary range finding test as follows: 0.032 - 0.100 - 0.320 - 1.00 - 3.20 - 10.0 mg/L. The test item Oleylnitrile was analytically verified in the fresh media (0 and 24 h) of all tested loading levels and control and in the old media (after 24 and 48 h) at the loading levels 0.100 and 1.00 mg/L and the control via GC-MS.

The samples of the fresh media (0 and 24 h) showed recoveries in the range of 44 to 62 % of the nominal values. The recoveries in the old media (after 24 and 48 h) were in the range of 34 to 66 % of the nominal values. Adsorption of the test item to the glassware was checked after an exposure period of 24 h at a test item concentration of 1.00 mg/L. The observed concentration after applying the concentration procedure (s. Preparation of Adsorption sample) was determined to be below LOQ_S showing that less than 5.7 % of the observed initial geometric mean concentration of 0.542 mg/L was sorbed to glassware. All effect values given are therefore based on the geometric mean of the initially measured concentrations of the test item in the fresh media (0 and 24 h), calculated to be: 0.0160 – 0.0569 – 0.155 – 0.542 – 1.90 – 5.91 mg/L. The mean recovery rates were in the range of 48 to 59 %.

The water quality parameters (pH-value and dissolved oxygen concentration), measured in the fresh media (0 and 24 h) and in the old media (24 and 48 h), were determined to be within acceptable limits. The validity criteria of the test guideline were fulfilled.

Table 1:    EC₁₀-, EC₅₀- (with Confidence Interval), EC₁₀₀- Values, NOEC and LOEC

(based on the geometric mean initially measured concentrations of the test item Oleylnitrile)

	Test Duration [h]	Oleylnitrile Geometric Mean Initially Measured Test Item Concentration [mg/L]	Confidence Interval p = 95% [mg/L]
EC10	24	0.0160	---
	48	0.0160	---
EC50	24	0.542	--
	48	0.0302	0.0262 – 0.0348
EC100	24	> 5.91	---
	48	0.155	---
NOEC	48	0.0160	---
LOEC	48	0.0569	---