Nuclease, deoxyribo-

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Study period:

1995-02-09 to 1995-08-30

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Read-across approach has been applied, as deoxyribonuclease has not been tested in a short-term toxicity study in fish, but due to the similarity between the two enzymes, similar results are expected.

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

yes

Remarks:

change of study monitor in april 1995

GLP compliance:

yes (incl. QA statement)

Remarks:

Certificate included in study report

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0 and 94.7 mg enzyme concentrate dry matter/L
- Sampling method: Duplicate samples from freshly prepared test media of the control and from the test concentration of 94.7 mg enzyme concentrate dry matter/L were taken at the start of the test, after 24h just after the first test medium renewal and at the end of the test at 96h.
- Sample storage conditions before analysis: Samples were stored deep-frozen at -20°C

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:The test medium was prepared by dissolving a weighed amount of the test substance directly in the test water in the aquarium. The test media was prepared just before introduction of fish.
- Controls: test water

Test organisms (species):

other: Oncorhynchus mykiss Walbaum

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Strain: Oncorhynchus mykiss Walbaum
- Source: Forellenhof Fredelsloh, Moringen, Germany
- Length at study initiation (length definition, mean, range and SD): 5.5 ± 0.11 cm
- Weight at study initiation (mean and range, SD): 2.0 ± 0.15 g

ACCLIMATION
- Acclimation period: 12 weeks
- Type and amount of food: commercial trout diet (Alleinfutter für Forellenbrut, Aminostart (extr.), Kraftfutterwerk Wesel GmbH, Wesel, Germany)
- Health during acclimation (any mortality observed): At least during the last three weeks prior to the start of the test no fish diet in the test fish batch

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

2.10 mmol/L (= 210 mg/L as CaCO3)

Test temperature:

13.1 - 14.6 °C

pH:

7.7 - 8.8

Dissolved oxygen:

8.1-10.4 mg/L

Nominal and measured concentrations:

nominal: 0 and 100 mg/L
measured: fresh samples were between 95.2 and 107.9% of the nominal value
test media taken at the end of the 24 hour renewal periods were between 90.2 and 91.2 % of the nominal value

Details on test conditions:

TEST SYSTEM
- Test vessel: aquarium
- Fill volume: 30 L test medium
- Aeration: slightly
- Renewal rate of test solution (frequency/flow rate): 24 hours
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: drinking water of the community Rossdorf; before use the total hardness was reduced in the laboratories of RCC and the water filtered through an activated carbon filter.
- Alkalinity: 4.60 mmol/L


OTHER TEST CONDITIONS
- Photoperiod: 16 hours light per day,
- Light intensity: appr. 50 - 300 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Fish were observed after 2, 24, 48, 72 and 96 hours test duration for symptoms of intoxication and mortality.

TEST CONCENTRATIONS
- Range finding study
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

94.7 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Remarks:

enyzme concentrate dry matter

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: no
- Mortality of control: 0
- Other adverse effects control: no
- Abnormal responses: no

Validity criteria fulfilled:

not specified

Conclusions:

The No-observed-effect concentration for alpha-amylase was the highest exposure concentration of 94.7 mg enzyme concentrate dry matter/L corresponding to 58.3 mg active enzyme protein/L.

Executive summary:

The acute toxicity of alpha-amylase to Rainbow Trout (Oncorhynchus mykiss) was determined in a 96‑hour semi-static test with a daily test medium renewal according to the OECD Guideline No. 203 and in compliance with GLP. 

A limit test was performed to demonstrate that the test substance has no toxic effect on the test animals up to the concentration of 94.7 mg enzyme concentrate dry matter/L corresponding to 58.3 mg active enzyme protein (aep)/L. The analysis of the exposure concentrations revealed that the test substance concentrations were within the range of 80 to 120% of the nominal value.

The 96h NOEC was determined to be 94.7 mg enzyme concentrate dry matter/L, corresponding to 58.3 mg aep/L. The 96h LC50 value could not be determined due to the absence of toxicity of the test substance but is clearly higher than 94.7 mg enzyme concentrate dry matter/L (58.3 mg aep/L).

Description of key information

Deoxyribonuclease has been tested in fish, but alpha-amylase was used as read-acorss. Alpha-amylase was not toxic at the the tested concentration of 94.7 mg enzyme concentrate dry matter/L.

The No-observed-effect concentration was the highest exposure concentration of 94.7 mg enzyme concentrate dry matter/L corresponding to 58.3 mg active enzyme protein/L.