Laccase

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:

25 January 1996 -15 April 1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Certificate included in study report

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 100 mg dry material per litre
- Sampling method: Duplicate samples from the control and the test solutions of SP807 were taken at 72h (newly prepared solution) and at 96h (spent solution after 24h). Samples of ca. 5 mL were taken in polyethylene bottles.
- Sample storage conditions before analysis: frozen

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 50 mL of the test substance was transferred to one aquaria, containing 30 litres of dilution water (DSWL), resulting in a test solution of 100 mg dry material per litre corresponding with a specific activity of 406 LACU per litre.
- Controls: Dilution water (DSWL)

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: rainbow trout
- Strain: Oncorhynchus mykiss
- Source: Keijzersberg in Blitterswijk, The Netherlands
- Length at study initiation (length definition, mean, range and SD): 5.3 +/-0.3 cm.
- Weight at study initiation (mean and range, SD): 3.08 +/- 1.13 g
- Feeding during test: no feeding.

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

205 mg CaCO3/L

Test temperature:

14.8°C - 15.1°C

pH:

7.7-8.0

Dissolved oxygen:

8.4 mg/L - 9.9 mg/L

Nominal and measured concentrations:

t=72h: the measured concentration was 64-67% of the nominal value
t=96h: the measured concentration was 79-81% of the nominal value.

Details on test conditions:

TEST SYSTEM
- Test vessel: glass aquarium
- Material, size, headspace, fill volume: glass, 46 litres containing 30 litre of control or test medium
- Aeration: yes
- Renewal rate of test solution (frequency): 24h
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates):1
- No. of vessels per control (replicates):1
- Biomass loading rate: 1g per litre

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Addition of several salts to ground water from a locality near Linschoten (The Netherlands)
- Total organic carbon: 1.7 mg/L
- Metals: << 1mg/L
- Chlorine: 2.76 mmol/L
- Alkalinity: 1.39 mmol HCO3-/L

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16h light/8h dark

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : After 3h, 25h, 48h, 72h and 96h dead and living animals were counted. At the same time the condition (swimming behaviour, colour or any other visually observable morphological or behavioural criterion) of the survivors was compared with that of the control animals.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: limit test

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: dry material

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 73 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: dry material

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: dry material

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

>= 73 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: dry material

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: dry material

Basis for effect:

other: condition

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

>= 73 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: dry material

Basis for effect:

other: condition

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

2.6 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

act. ingr.

Remarks:

active enzyme protein

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

2.6 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

act. ingr.

Basis for effect:

mortality (fish)

Details on results:

- Mortality of control: 10%

Validity criteria fulfilled:

not specified

Conclusions:

No mortality was observed following the exposure of Oncorhynchus mykiss to the test substance at a concentration of 73 mg dry material/L. Due to the low toxicity of the test material, the 96-hour LC50 value of the substance was unable to be calculated. Therefore the following values were assumed:
The 96-hour LC50 value for the test substance with rainbow trout was determined to be >73 mg dry material/L corresponding to 2.64 > mg active enzyme protein (aep)/L.
The no-observed effect concentration (NOEC) was 73 mg dry material per litre corresponding to 2.64 mg aep/L.

Executive summary:

An acute toxicity test to rainbow trout (Oncorhynchus mykiss) was conducted to determine the effect of laccase on fish. The study was conducted in accordance with OECD and EC guidelines, and in compliance with GLP.

The test substance was not acutely toxic to rainbow trout as no mortality was observed during the 96 hour exposure period.

Test concentrations are based on dry material. Verification of test concentrations was performed based on enzyme activity. The amount of measured enzyme activity was then converted to mg dry material/L in order to calculate the achieved measured concentrations.

No mortalities were observed in the test group and therefore the 96-hour LC50 was considered greater than the maximum concentration tested. The following results are expressed in terms of the mean measured concentration:

96-hour LC50: > 73 mg dry material/L or >2.6 mg active enzyme protein (aep)/L

Highest concentration resulting in 0% mortality: 73 mg dry material/L or > 2.6 mg aep/L

Lowest concentration resulting in 100% mortality: >73 mg dry material/L or > 2.6 mg aep/L

No-observed effect concentration (NOEC): 73 mg dry material/L or > 2.6 mg aep/L

Description of key information

No mortality was observed following the exposure of Oncorhynchus mykiss to the test substance at a concentration of 73 mg dry material/L. Due to the low toxicity of the test material, the 96-hour LC50 value of the substance was unable to be calculated. Therefore the following values were assumed: The 96-hour LC50 value for the test substance with rainbow trout was determined to be >73 mg dry material/L corresponding to > 2.6 mg aep/L. The no-observed effect concentration (NOEC) was 73 mg dry material per litre corresponding to 2.6 mg aep/l.

Additional information

An acute toxicity test to rainbow trout (Oncorhynchus mykiss) was conducted to determine the effect of laccase on fish. The study was conducted in accordance with OECD and EC guidelines, and in compliance with GLP.

The test substance was not acutely toxic to rainbow trout as no mortality was observed during the 96 hour exposure period.

Test concentrations are based on dry material. Verification of test concentrations was performed based on enzyme activity. The amount of measured enzyme activity was then converted to mg dry material/L in order to calculate the achieved measured concentrations.

No mortalities were observed in the test group and therefore the 96-hour LC50 was considered greater than the maximum concentration tested. The following results are expressed in terms of the mean measured concentration:

96-hour LC50: > 73 mg dry material/L or >2.6 mg aep/L

Highest concentration resulting in 0% mortality: 73 mg dry material/L or > 2.6 mg aep/L

Lowest concentration resulting in 100% mortality: >73 mg dry material/L or > 2.6 mg aep/L

No-observed effect concentration (NOEC): 73 mg dry material/L or 2.6 mg aep/L