Potassium cyanate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

not applicable

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

not indicated.

Vehicle:

no

Details on test solutions:

not indicated.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

Common name: Rainbow trout
The mean weight of the fish varied from 0.4 to 1.3 g during the experiment.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

no post exposure period

Hardness:

75 mg/L CaCO3

Test temperature:

5 or 12 °C

pH:

pH 6 or pH 8

Dissolved oxygen:

between 80 and 100 % O2 saturation

Salinity:

conductivity in cyanates assays: 310 to 500 µmhos/cm
control: 250 µmhos/cm

Nominal and measured concentrations:

Measured concentrations were always within 10 % of the nominal concentration.

Details on test conditions:

not indicated.

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

15 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: at pH 6 and 5 °C

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

34 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: at pH 6 and 12 °C

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

45.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: at pH 8 and 5 °C

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

80.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: at pH 8 and 12 °C

Details on results:

At both pH conditions cyanate was significantly less toxic at the higher test temperature (12 °C) than at the lower one (5 °C). The test conditions under which cyanate was most toxic to rainbow trout was pH 6 and 5 °C. The next most toxic condition was pH 6 and 12 °C, and the least toxic was pH 8 and 12 °C. It is apparent that pH had a greater influence than did temperature.

Results with reference substance (positive control):

no reference substance

Reported statistics and error estimates:

not indicated.

Validity criteria fulfilled:

yes

Conclusions:

The mean 96 h LC50 for potassium cyanate varied from 15 to 81 mg/L, depending on the pH and temperature of the test water.

Executive summary:

In a 96-h acute toxicity study, Salmo gairdneri (rainbow trout) were exposed to potassium cyanate under static conditions. The mean 96 h LC50 for potassium cyanate varied from 15 to 81 mg/L, depending on the pH and temperature of the test water. At both pH conditions potassium cyanate was significantly less toxic at the higher test temperature (12 °C) than at the lower one (5 °C). The test conditions under which potassium cyanate was most toxic to rainbow trout was pH 6 and 5 °C. The next most toxic condition was pH 6 and 12 °C, and the least toxic was pH 8 and 12 °C. It is apparent that pH had a greater influence than did temperature. This toxicity study is classified as acceptable as it is conducted equivalent or similar to EU C.1 and OECD 203.

Results Synopsis:

Test organism size (wet weight): 0.4 to 1.3 g

Test Type: static

LC50 (pH 6, 5 °C) = 15 mg/L

LC50 (pH 6, 12 °C) = 34 mg/L

LC50 (pH 8, 5 °C) = 45.4 mg/L

LC50 (pH 8, 12 °C) = 80.6 mg/L

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

from 2009-04-20 to 2009-07-06

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

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.

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.

GLP compliance:

yes (incl. QA statement)

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 meas-urement 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 surpass 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
Feeding three times a day with warm water fish food 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 49mg /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

Reference 3

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1953

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: non guideline test

Qualifier:

no guideline followed

Principles of method if other than guideline:

No guideline indicated. Principles of method see below.

GLP compliance:

not specified

Analytical monitoring:

not specified

Details on sampling:

not indicated.

Vehicle:

no

Details on test solutions:

not indicated.

Test organisms (species):

other: Kuhlia sandvicensis

Details on test organisms:

not indicated.

Test type:

static

Water media type:

saltwater

Limit test:

no

Remarks on exposure duration:

Not indicated, minimum 2 min.

Post exposure observation period:

not indicated.

Hardness:

not indicated.

Test temperature:

not indicated.

pH:

not indicated.

Dissolved oxygen:

not indicated.

Salinity:

not indicated.

Nominal and measured concentrations:

10 and 20 ppm

Details on test conditions:

not indicated.

Reference substance (positive control):

yes

Remarks:

other chemicals with positive reactions were tested in parallel

Key result

Dose descriptor:

NOEC

Effect conc.:

> 20 other: ppm

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: duration: minimum 2 min

Details on results:

not indicated.

Results with reference substance (positive control):

not indicated.

Reported statistics and error estimates:

not indicated.

Validity criteria fulfilled:

not specified

Conclusions:

Potassium cyante showed no abservable effects to Kuhlia sandvicensis up to a concentration of 20 ppm.

Executive summary:

In an acute toxicity study, Kuhlia sandvicensis were exposed to potassium cyanate at nominal concentrations of 10 and 20 ppm under static conditions. Potassium cyante showed no abservable effects to Kuhlia sandvicensis up to a concentration of 20 ppm. Thus, the NOEC was derived to > 20 ppm. This toxicity study is classified as acceptable as supporting study.

Results Synopsis:

Test Type: static

NOEC: 20 ppm

This value supports the selected NOAEL of 20 mg/L for risk assessment. As Weight of Evidence, 20 mg/L was justified, based on the studies with potassium cyanate and one study with sodium cyanate.

Reference 4

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1988

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

No guideline indicated. Principles of method see below.

GLP compliance:

not specified

Analytical monitoring:

not specified

Details on sampling:

not indicated.

Vehicle:

not specified

Details on test solutions:

not indicated.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

Rainbow trout, donaldson trout, fingerlings

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

not indicated.

Hardness:

not indicated.

Test temperature:

not indicated.

pH:

not indicated.

Dissolved oxygen:

not indicated.

Salinity:

not indicated.

Nominal and measured concentrations:

not indicated.

Details on test conditions:

not indicated.

Reference substance (positive control):

not specified

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

24.3 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95 % confidence interval: 16.8 - 31.8 mg/L

Details on results:

not indicated.

Results with reference substance (positive control):

no reference substance.

Reported statistics and error estimates:

not indicated.

Validity criteria fulfilled:

not specified

Conclusions:

LC50 Oncorhynchus mykiss (Rainbow trout, donaldson trout, fingerlings) = 24.3 mg/L/96 hr (95 % confidence interval: 16.8 - 31.8 mg/L)

Executive summary:

In a 96-h acute toxicity study, Oncorhynchus mykiss (Rainbow trout, donaldson trout, fingerlings) were exposed to potassium cyanate under static conditions. The 96-h LC50 was 24.3 mg /L.

This toxicity study is classified as acceptable.

 

Results Synopsis

Test Type: static

LC50: 24.3 mg/L

95 % C.I.: 16.8 to 31.8 mg/L

 

This value supports the selected NOAEL of 20 mg/L for risk assessment. As Weight of Evidence, 20 mg/L was justified, based on the studies with potassium cyanate and one study with sodium cyanate.

Description of key information

The lowest LC50 identified was 15 mg/L in Salmo gairdneri. In a read-across study with the structural analogue sodium cyanate, which was conducted recently according to OECD and EU Guidelines and GLP a LC50 of 94 mg/L was determined in Danio rerio, supports the high values noted with Salmo at high testing.
As a Weight of Evidence, 20 mg/L was justified, based on the studies with potassium cyanate and one study with sodium cyanate.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

20 mg/L

Additional information

Key studies:

- In a 96-h acute toxicity study, Salmo gairdneri (rainbow trout) were exposed to potassium cyanate under static conditions. The mean 96 h-LC50 for potassium cyanate varied from 15 to 81 mg/L, depending on the pH and temperature of the test water. At both pH conditions potassium cyanate was significantly less toxic at the higher test temperature (12 °C) than at the lower one (5 °C). Test conditions under which potassium cyanate was most toxic to rainbow trout were pH 6 and 5 °C. The next most toxic condition was pH 6 and 12 °C, and the least toxicity was observed for pH 8 and 12 °C. It is apparent that pH had a greater influence than temperature. This toxicity study is classified as acceptable as it is conducted equivalent or similar to EU C.1 and OECD 203.

 

- In a 96-h acute toxicity study (Muckle, 2009), 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, equal to 61.1 mg/L potassium cyanate.

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

 

Supporting Studies:

- In a 96-h acute toxicity study, Oncorhynchus mykiss (Rainbow trout, donaldson trout, fingerlings) were exposed to potassium cyanate under static conditions. The 96-h LC50 was 24.3 mg/L.

This toxicity study is classified as acceptable as supporting study.

 

- In an acute toxicity study, Kuhlia sandvicensis were exposed to potassium cyanate at nominal concentrations of 10 and 20 ppm under static conditions. Potassium cyanate showed no observable effects to Kuhlia sandvicensis up to a concentration of 20 ppm. Thus, the NOEC was derived to > 20 ppm. This toxicity study is classified as acceptable as supporting study.

 

As a Weight of Evidence, 20 mg/L was justified, based on the studies with potassium cyanate and one study with sodium cyanate.