diuron (ISO); 3-(3,4-dichlorophenyl)-1,1-dimethylurea

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Stock solutions were prepared by solving the test item in acetone.
- Chemical name of vehicle: Acetone
- Controls: Yes, solvent controls used
- Concentration of vehicle in test medium: 0.3 mL acetone p.a./L in the first part (concentration range 0.45 - 10.0 mg/L) and 2.2 mL acetone p.a./L in the second part (concentration range 21.5 - 100 mg/L)

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Source: Local hatchery (Müller, G. Moringen, Germany); obtained as eyed eggs and hatched in testing facility
- Length at study initiation: At test start the mean body length were 6.5 cm (1st part) and 6.8 cm (2nd part)
- Weight at study initiation: 2.7 g ± 0.7 g (1st part) and 2.8 g ± 0.6 g (2nd part)
- Feeding during test: No food was provided during the study period

ACCLIMATION
- Acclimation period: at least 14 days prior to testing
- Acclimation conditions: In culture tanks on a 16/8 hour light/dark photoperiod
- Type and amount of food: Commercial trout diet diet (Brutfutter FB50, Fischkraftfutter, Wesel, Germany)
- Feeding frequency: daily - feeding stopped 48 h before study
- Health during acclimation (any mortality observed): less than 3% mortality prior to test and all unsuitable fish (injured, deformed, etc) were eliminated from inclusion in the test.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

40 - 60 mg/L CaCO3

Test temperature:

12±1 °C

pH:

7.1 to 7.6

Dissolved oxygen:

10.6 to 11.6 mg/L

Salinity:

not applicable

Nominal and measured concentrations:

The study was performed in two parts: 1st part: 0.45, 1.0, 2.15, 4.65 and 10.0 mg /L, 2nd part: 21.5, 46.5 and 100 mg /L
These are nominal concentrations; actual concentrations are given in Table 1

Details on test conditions:

TEST SYSTEM
- Test vessel: glass aquaria; 32x36x38cm
- Fill volume: fill volume of 40 litres.
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- No. of vessels per vehicle control (replicates): 1
- Biomass loading rate: 0.7 g/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to guideline (see Table 2 for composition)
- Intervals of water quality measurement: Water pH and dissolved Oxygen were recorded at test start and every 24 hours. Analytical determinations of Diuron concentration were made from samples taken from each treatment group at the start and at every 24 h interval.

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16h light, 8h dark photoperiod daily
- Light intensity: Not stated

EFFECT PARAMETERS MEASURED : Mortality; Sampling interval: Start of test then every 24 hours

Reference substance (positive control):

not specified

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

14.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CL

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

21.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

At low concentration levels up to 4.65 mg /L fish showed no or only slight differences in behaviour compared to the control group
At a concentration of 10.0 mg /L and higher fish showed severe sublethal effects.
Irregular swimming behaviour was observed at 2.15 mg /L and higher concentrations.
Fish lying on the side, swollen belly or apathetic fish were observed at 10.0 mg Diuron/L and higher concentrations.
Mortality was observed at 21.5 to 100 mg Diuron/L

Reported statistics and error estimates:

The LC50 was determined by Probit analysis, moving average or binominal probability, depending on data characteristic.

Sublethal observations / clinical signs:

The mean concentration of the test items was exceeding 80 %. Thus the results were evaluated based on nominal concentrations.

Table 3. Mortality data:

Test-Substance Concentration (nominal)^1 [mg/L]	Mortality
	Number 24 h         48 h         72h         96 h				Percentage    24 h        48 h         72 h          96 h
Control	0	0	0	0	0	0	0	0
Solvent control	0	0	0	0	0	0	0	0
0.45	0	0	0	0	0	0	0	0
1.00	0	0	0	0	0	0	0	0
2.15	1	1	1	1	10	10	10	10
4.65	0	0	0	0	0	0	0	0
10.0	0	0	0	0	0	0	0	0
21.5	0	6	10	-	0	60	100	-
46.5	10	-	-	-	100	-	-	-
100	10	-	-	-	100	-	-	-
Tempera­ture [°C]	12±1°C	12±1°C	12±1°C	12±1°C
pH	7.1 – 7.2	7.3 – 7.6	7.0 – 7.2	7.2
Oxygen [mg/L]	10.1 – 11.2	10.2 – 10.9	10.1 – 10.8	10.4 – 10.9

 

Table 4          Effect data

	48 h [mg/L]^1	95 % c.l.	96 h [mg/L]^1	95 % c.l.
LC0	10.0	n.d.	10.0	n.d.
LC50	19.5	10.0 – 46.4mg/L	14.7	10.0 – 21.5mg/L
LC100	46.4	n.d.	21.5	n.d.
^1all effects are based on nominal concentrations.

 

Table 5          Validity criteria for acute fish test according to OECD Guideline 203

	fulfilled	Not fulfilled
Mortality of control animals <10%	X
Concentration of dissolved oxygen in all test vessels > 60% saturation	X
Concentration of test substance = 80% of initial concentration during test	X

 

Executive summary:

A short term acute toxicity test with juvenile Rainbow trout, according to OECD guideline 203 with GLP, is available for this test substance.

This study is based on nominal concentrations (where measured concentrations were always above 80% of the nominal) and calculated the LC50 (96h) to be 14.7 mg/L.

Therefore the test substance is found to be acutely harmful to fish, evidenced by the LC50 value of > 10mg/L yet < 100 mg/L

Description of key information

Diuron is acutely harmful to fish

Additional information

A short term acute toxicity test with juvenile Rainbow trout, according to OECD guideline 203 with GLP, is available for this test substance.

This study is based on nominal concentrations (where measured concentrations were always above 80% of the nominal) and calculated the LC50 (96h) to be 14.7 mg/L. Therefore the test substance is found to be acutely harmful to fish, evidenced by the LC50 value of > 10mg/L yet < 100 mg/L (Dorgerloh, 1993)