Sodium cyanate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from2009-04-20 to 2009-07-06

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

yes

Remarks:

The temperature for the main study was higher than stated in the guidelines. As no abnormal behaviour of the fish was observed in the control, this deviation was stated as uncritical.

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

yes

Remarks:

The temperature for the main study was higher than stated in the guidelines. As no abnormal behaviour of the fish was observed in the control, this deviation was stated as uncritical.

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
not indicated.

Analytical monitoring:

yes

Details on sampling:

Standard solutions containing 10 and 100 mg/L of the test item were measured twice each after 0, 24 and 96 hours. The recovery rate after 96 hours storage at room temperature was determined as 94 % and 96.3 %.
Description of Sample Measurement
1.0 mL of the respective sample was mixed with 1.0 mL 2-Aminobenzoic acid (0.02 mol/L). The mixture was left to react at 40 °C for 10 minutes. Then, 2 ml HCl conc. were added and the mixture was heated to 100 °C for 1 minute. After cooling, the photometric measurement at 310 nm was performed.

Vehicle:

no

Details on test solutions:

On the day of the start of the test, a stock solution containing 10.000 mg/L test item was prepared. This solution was used to prepare a series of five concentrations in the range of 10 – 100 mg/L.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

Specification
Species Danio rerio HAMILTON-BUCHANAN
Age sexually immature young fish, length 2 +/- 1 cm
Origin
The animals were obtained from a commercial supplier. Before being used for the test, the fish were kept for 14 days under test conditions. During this period, mortality didn´t exceed 5 %.
Supplier: Dehner Garten Center, 67433 Neustadt
Date of arrival: 18. Mar. 2009
Husbandry
Danio rerio is routinely used for toxicity tests. The test fish are kept following SOP 115 005 04 in the current edition.
Vessels polyethylene aquaria
Medium chlorine-free tap water, full composition see annex
Feeding three times a day with warmwater fishfood and daphnia, totalling to about 1-2% of body weight per day
Medium renewal twice a week
Photo period 12/12 hours, using neon tubes
Temperature 23 +/- 1 °C

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

no post exposure period

Hardness:

0.91 mmol/L

Test temperature:

26.4 - 25.6

pH:

7.6-7.9

Dissolved oxygen:

7.8-8.3

Salinity:

freshwater used

Nominal and measured concentrations:

nominal: 0, 10, 18, 32, 56, 100 mg/L
measured (mean between 0 and 96 h): 8.18, 13.61, 18.69, 48.65, 95.88 mg/L
Each concentration was measured threefold. The mean of the measured concentration after 96 hours was in a range of 76 % and 141 % of the start concentration. The mean of the measured concentration at the beginning was in a range of 64 % – 91 % and at the end between 51 % - 102 % of the nominal concentration. Therefore, the determination of the biological results was based on the mean of the measured concentration.

Details on test conditions:

Observations were made every 24 hours, measuring pH and O2-concentration of the test solutions in each vessel and documenting mortalities or abnormal behaviour. The content of the test item in the test vessels was measured at the beginning and at the end of the study.
A fish was considered dead, if no visible movement could be observed, and if touching of the caudal peduncle produced no reaction.

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

94 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

49 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

All validity criteria were met.
For the estimation of the LC50s of the test item, only the highest test concentration shows mortality. The fits showed sufficient statistical correspondence of the data with the dose-response-equation.
The correlation between nominal and measured concentrations and the recovery rates was acceptable. In treatment 100 mg/L, the correlation between nominal and measured concentration was very good. As only in treatment 100 mg/L mortality was observed, the large variation in the measured values in the lower concentrated treatments can be stated as uncritical. The measured concentrations at the end of the test were more than 100 % of the start concentration. This might be caused by evaporation of dilution water and there-fore higher measured concentrations at the end of the test.

Results with reference substance (positive control):

no positive control.

Reported statistics and error estimates:

The estimation of the EC50 was accomplished using the software OriginTM. The calculated values for p resp. χ2 are given in the graph.
The data were evaluated using sigmoidal fit on a linear-logarithmic scale.

Validity criteria fulfilled:

yes

Conclusions:

The following results for acute toxicity to fish (Danio rerio) for the test item sodium cyanate were determined:
96h NOEC = 49 mg/L
96h LC50 = 94 mg/L

Executive summary:

In a 96-h acute toxicity study, Danio rerio (HAMILTON-BUCHANAN) were exposed to sodium cyanate at measured concentrations of 0 8.18, 13.61, 18.69, 48.65, 95.88 mg/L under static conditions. The main study was performed using five concentrations ranging from 10 to 100 mg/L.

At the beginning and at the end of the test, the content of the test item in the test solutions was determined using a spectral photometer. The recovery after 96 hours ranged from 76 % to 141% of the start concentration. The correlation between nominal and measured concentration ranged from 64 % to 91% at the beginning and 51 % to 102 % at the end. Therefore, the determination of the biological results was based on the geometric mean of the measured concentration.

The 96 h-LC50 was 94 mg /L. The NOEC value, based on mortality/sublethal effects, was 49 mg/L, respectively.

This toxicity study is classified as acceptable and satisfies the guideline requirement for acute toxicity to fish studies.

Results Synopsis

Test organism size: 2 +/- 1cm

Test Type: Static

LC50: 94 mg/L

NOEL: 49 mg/L

Description of key information

The following results for acute toxicity to fish (Danio rerio) for the test item sodium cyanate were determined:
96h NOEC = 49 mg/L
96h LC50 = 94 mg/L

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

94 mg/L

Additional information

Key study:

In a 96-h acute toxicity study, Danio rerio (HAMILTON-BUCHANAN) were exposed to sodium cyanate at measured concentrations of 0 8.18, 13.61, 18.69, 48.65, 95.88 mg/L under static conditions. The main study was performed using five concentrations ranging from 10 to 100 mg/L.

At the beginning and at the end of the test, the content of the test item in the test solutions was determined using a spectral photometer. The recovery after 96 hours ranged from 76 % to 141% of the start concentration. The correlation between nominal and measured concentration ranged from 64 % to 91% at the beginning and 51 % to 102 % at the end Therefore, the determination of the biological results was based on the geometric mean of the measured concentration.

The 96 h-LC50 was 94 mg /L. The NOEC value, based on mortality/sublethal effects, was 49 mg/L, respectively.

This toxicity study is classified as acceptable and satisfies the guideline requirement for acute toxicity to fish studies.

Supporting Study:

In an acute toxicity study, creek chub (Semolitus a. atromaculatus) were exposed to sodium cyanate. The maximum tolerance limit is 75 ppm. This toxicity study is classified as acceptable as supporting study.