Salicylonitrile

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

10 May 2010 - 13 May 2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

No analytical monitoring

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

yes

Remarks:

No analytical monitoring

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Details on sampling:

Not applicable

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution of nominal 46 mg/L was prepared by dissolving 46.1 mg of test item in 1000 mL of test water using ultrasonic treatment for 15 minutes and intense stirring for 15 minutes. This was diluted with test water to produce the range of test item concentrations.
- Controls: Blank control (test water only). Potassium dichromate is tested as a positive control twice a year.
- Evidence of undissolved material (e.g. precipitate, surface film, etc): No

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Strain: Clone 5
- Source: In lab culture, original source University of Sheffield / UK in 1992
- Age at study initiation (mean and range, SD): 6-24 hours
- Feeding during test: no

ACCLIMATION
- Acclimation period: Breeding conditions same light and temperature conditions as test. Parental daphnids maintained in test water for ≤ 48 hours prior to test start
- Acclimation conditions (same as test or not): Yes

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

None

Hardness:

150 mg CaCO3/L

Test temperature:

20-21°C

pH:

7.0 - 7.8

Dissolved oxygen:

8.0 - 8.5 mg/L

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal concentrations: Control, 1.0, 2.2, 4.6, 10, 22, 46 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Beakers
- Type (delete if not applicable): closed (covered with glass plates)
- Material, size, headspace, fill volume: 250 mL glass beakers filled with 125 mL of test medium
- Aeration: Prior to test but not during.
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted test water (analytical grade salts dissolved in purified water) according to ISO 6341, with hardness lowered to meet OECD and EPA guideline requirements.
- Intervals of water quality measurement: Beginning and end of test. Appearance of test media also evaluated at 24 hours.

OTHER TEST CONDITIONS
- Adjustment of pH: None reported
- Photoperiod: 16:8 light/dark cycle with 30 minute transition period.
- Light intensity: 520-680 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Immobility. Daphnids considered immobile if they do not swim after 15 seconds of gentle agitation.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2.15
- Range finding study: Yes
- Results used to determine the conditions for the definitive study: Yes

Reference substance (positive control):

yes

Remarks:

Potassium dichromate, tested twice a year

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

40 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 30 - 73 mg/L

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

18 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 14-24 mg/L

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

4.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

See table 1.

Results with reference substance (positive control):

Most recent test (March 2010, study C86933) reported an EC50 of 0.43 mg potassium dichromate/L. This demonstates the senstivity of the test organisms and is within the internal historical range (0.43 - 1.1 mg/L)

Reported statistics and error estimates:

24- and 48-hour EC50s and 95% confidence limites calculated by Probit analysis.
NOEC determined directly from the raw data.

Table 1. Effect of the substance on the Mobility of Daphnia magna

Nominal test item concentration (mg CA3688A/L)	No. of daphnids tested	Immobilized daphnids after 24 hours		Immobilized daphnids after 48 hours
		No.	%	No.	%
Control	20	0	0	0	0
1	20	0	0	0	0
2.2	20	0	0	0	0
4.6	20	0	0	0	0
10	20	0	0	6	30
22	20	7	35	11	55
46	20	10	50	18	90

Validity criteria fulfilled:

yes

Remarks:

Mortality in controls <10%; DO levels at end of test > 3 mg/L

Conclusions:

The 48-EC50 for Daphnia magna exposed to the test material was determined to be 18 mg/L. The 48-hour NOEC was determined to be 4.6 mg/L

Executive summary:

The sensitivity of Daphnia magna to the substance was determined in a GLP-compliant test performed to standard guidelines. The 48-hour EC50 was found to be 18 mg/L with 95 % confidence intervals of 14 - 24 mg/L. The 48-hour NOEC was determined to be 4.6 mg/L. All results are based on nominal concentrations.

Description of key information

EC50=18mg/L, 48h, Daphnia magna, OECD 202, Höger 2010
EC50=19.8mg/L, 48h, Ceriodaphnia cf. dubia, no guideline, Westbury 2004

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

18 mg/L

Additional information

Westbury (2004) determined the acute toxicity of the substance to Ceriodaphnia cf. dubia, as part of the development of a QSAR model for substituted phenols. The experimental procedure was similar to OECD guideline 202, with a potentially reduced number of animals (replicates). Concentrations were monitored analytically at both beginning and end of the experiment. The 48h EC50 was reported to be 19.8mg/L; it was not stated whether this was based on measured initial concentration, or the geometric mean of initial and final concentrations. As stated by the authors, the methodology and validity criteria were adhered to. However, the lack of reported raw data prevents the independent interpretation of the experimental data.

The acute toxicity of the substance to Daphnia magna was determined in a 48-hour static test under GLP and according to OECD Guideline 202 (2004), by Höger (2010). The nominal test item concentrations tested were control group, 1.0, 2.2, 4.6, 10, 22 and 46 mg/L. No analytical measurements were performed in the test. The 48h EC50 was found to be 18mg/L (14-24mg/L, CI=95%).

 

The chemical structure is not expected to be hydrolytically unstable, nor is there experimental evidence to suggest this. The stability of the test substance in the test media of an algae growth inhibition study (OECD 201) over a 96h-hour period was confirmed by Liedtke (2010) with analytical monitoring. Test concentrations were between 100 and 107% at the end of the study.

 

The two available studies both have shortcomings in either the experimental design or extent of reported data. However, it is considered that these deficiencies are independent and the similar toxicities reported (despite the possible differing species sensitivities) lend credibility to the results. Finally, no evidence of hydrolytic instability was observed in a subsequent algae study with analytical monitoring of the test material concentrations.

 

The lowest effect concentration, EC50=18mg/L, is selected from the two available studies as being the most conservative value for risk assessment and classification purposes.

 

As a result the available data is considered to be adequate for classification and labelling and risk assessment based on the weight-of-evidence, in accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.2.