O-ethylhydroxylamine

Long-term toxicity to fish

Administrative data

Endpoint:

fish, juvenile growth test

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study with analytical monitoring of the stock solutions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1987

Report date:

1987

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 204 (Fish, Prolonged Toxicity Test: 14-day Study)

Principles of method if other than guideline:

Duration of the test: 21 days

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

O-ethylhydroxylamine

EC Number:

402-030-3

EC Name:

O-ethylhydroxylamine

Cas Number:

624-86-2

Molecular formula:

C2 H7 N O

IUPAC Name:

O-ethylhydroxylamine

Details on test material:

- Name of test material (as cited in study report): H109360 & Q125
- Physical state: colourless liquid
- Analytical purity: solution with a stated water content of 50%
- Lot No.: EPI-100
- Storage condition of test material: darkness at 5 °C

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A master stock concentrate of Q125 was prepared at a concentration of 10 ml/L water. Secondary stock solutions for dosing to the test vessels were prepared by appropriate dilution with water to give concentrations of 250, 140, 80, 25, 14 mg*/L (* the density of Q125 was assumed to be 1 g/ml. ) The equivalent concentrations of Substance H109360 were 125, 70, 40, 12.5, 7.0 mg/L respectively.

Test organisms

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Source: obtained from Zeals Fish Farm, Wolverton, Wiltshire on 26 May 1987 and held in stock tanks of the Brixham Laboratory
- Weight at study initiation (range): 2.95 - 4.07 g
- Length at study initiation (range): 58 - 68 mm

ACCLIMATION
- Acclimation period: 7 days to the test temperature of 15 ± 1°C

FEEDING DURING TEST
- Food type: BP Mainstream salmon fish
- Amount: 4% of the day 0 body weight/day
- Frequency: 2 feeds/day on weekdays; one feed/day at the weekend

Study design

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Test conditions

Hardness:

44 - 51 mg/L CaCO3

Test temperature:

15 ± 1 °C

pH:

6.9 - 7.4

Dissolved oxygen:

7.4 - 9.8 mg/L

Nominal and measured concentrations:

Nominal stock solution concentrations: 14, 25, 80, 140, 250, 10000 (master stock) mg/L Q125
Measured stock solution concentrations (mean): 13, 23, 80, 141, 256, 10600 (master stock) mg/L Q125
Nominal test concentrations: control, 0.0056, 0.01, 0.032, 0.056, 0.1 mg/L Q125

Details on test conditions:

TEST SYSTEM
- Test vessel: The test vessels used for the study were nominal 40 L rectangular glass tanks with loose-fitting glass lids.
- Type of flow-through: peristaltic diluter
- Renewal rate of test solution (frequency/flow rate): These secondary stock solutions were fed to the test vessels at a nominal 0.1 ml/min and mixed with dilution water at a nominal 250 ml/min to give the required concentrations of 0.1, 0.056, 0.032, 0.01, 0.0056 mg Q125/L . Equivalent concentrations of Substance H109360 were 0.05, 0.028, 0.016, 0.005, 0.0028 mg/L respectively . The secondary stock solutions were freshly made up from the master stock on Monday, Wednesday and Friday thoughout the 21-day test period
- No. of organisms per vessel: 16
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: water from Brixham town supply
- Conductivity: 120 - 150 µS/cm
- Intervals of water quality measurement: Twice weekly measurements were undertaken for pH, dissolved oxygen and temperature. Hardness and conductivity of the water supply used for the experiments was measured on Monday to Friday

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light and 8 hours darkness
- Light intensity: fluorescent lighting

EFFECT PARAMETERS MEASURED: mortality, symptoms, growth (weight, length) after 21 days

Results and discussion

Effect concentrations

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

>= 0.05 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- No físh deaths or symptoms of toxicity were recorded throughout the 21 day test period
- Weight gain and food conversion efficiency of the control fish were slightly less than those of the fish exposed to Substance H109360 .
- There appears to be no dose-related effect in the exposed fish and it is concluded that the weight gain/food conversion efficiency reduction in the control fish relative to the exposed fish is adventitious and not attributable to Substance H109360
- Observations of físh behaviour both at the time of feeding and períodically on other occasions throughout the test showed no differences between the exposure and control populations.

On this basis it is considered that the 0.05 mg/L concentration of substance H109360 represents a "no effect" level in respect of this 21 day growth study on rainbow trout.