1,3-di-o-tolylguanidine

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2003

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

pH values on the concentrations of 14 and 25 mg/L (8.5-8.8) were higher than that on the control and the solvent control (8.0-8.2). These higher pH values were caused by the test substance, but these were acceptable range to test organisms. pH of test solutions were not adjusted during test period.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

1984

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

0.75mL of the test solution was sampled from each test container in each of the test groups at the beginning and end of exposure. After mixing an equivalent amount of acetonitrile, HPLC analysis was conducted. The test substance for each test solution was quantified from the ratio to the peak area of the standard solution.

Vehicle:

yes

Details on test solutions:

The dilution water used for preparing the test solution was aerated prior to preparation and brought to 20±1°C in the constant temperature tank. The test substance concentrate-1, and test substance concentrate-2 were prepared as follows:

Test substance concentrate -1:

Amount of test substance sampled: 1250 mg
Constant solution: Dimethylformamide
Constant volume: 5 mL
Dissolution method: hand shaken
Test substance concentration: 250 000 mg/L
Preparation Frequency: at the beginning of exposure
Storage conditions: room temperature

Test substance concentrate -2:

Amount of test substance sampled: 25.0 mg (100µL of test substance solution -1 sampled)
Constant solution: Dilution water
Constant volume: 1000 mL
Dissolution method: Ultrasonic mechanical dissolution (5 min)
Test substance concentration: 25 mg/L auxiliary agent (dimethylformamide)
Concentration: 100 µL/L
Preparation Frequency: at the beginning of exposure
Storage conditions: not stored

The test substance concentrate-2 was sampled corresponding to the concentrations of the test shown, and simultaneously, the auxiliary agent concentration was sampled with 500 mL of the dilution solution so the auxiliary agent concentration was at a constant level (auxiliary agent concentration: 100uL/L) in all of the concentration groups.

The control group was prepared with only the dilution water, and the auxiliary agent control group contained only the auxiliary agent (auxiliary agent concentration: 100uL/L).

Test organisms (species):

Daphnia magna

Details on test organisms:

1) Common Name: Water flea

2) Scientific Name: Daphnia Magna

3) Supplier: Environment Agency, National Environment Laboratory (currently an independently administered national environmental laboratory)

4) Date Received: 7/18/1995

5) Sensitivity: Acute inhibitory testing performed on a regular basis (approximately every 6 months) on a standard substance (potassium dichromate, analytical grade reagent), 50% effective inhibitory concentration (EC50) in a 48 hour period was conducted according to the below, after 6/1986. (Mean value ± standard deviation = 0.753 ± 0.17mg/L, n=10 ; Minimum value ~ maximum value = 0.57 ~ 1.0 2mg/L)

6) Breeding Stages: Young females (24 hours or less)

7) Breeding Conditions of Parent Daphnia Magna to Produce Test Organism
Breeding Water: Dilution water
Breeding Density: 1 organism/80mL (25 anmials/2L) or less
Breeding Container: 2L glass container
Water Temperature: 20 ±1°C
Dissolved Oxygen Concentration: 60% or more of the saturated concentration
pH: 6.7 ~ 8.5
Illumination: Room lighting, 16 hours of light (800 lux or less)/ 8 hours of dark
Breeding Period: 3/19/2003 ~ 4/9/2003
Mortality Rate of Parents for 2 Weeks Prior to Start of Exposure: <5%
Dormant Eggs and Males Generated: None
Type of Food: Chlorella vulgaris (single celled green algae, (the algae breeding solution was centrifugally filtered and replaced with dilution water)
Quantity of Food Provided: 0.2mg C (amount containing organic carbon)/organism/day
Replacement of Breeding Water: Replaced on a regular basis (3 times/week). Offspring were eliminated daily.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48

Hardness:

approximately 250 mg/L (CaCo3 displacement)

Test temperature:

20 +/- 1°C

pH:

8.0 - 8.8

Dissolved oxygen:

8.1 - 8.8 mg/L

Nominal and measured concentrations:

Nonminal concentrations / measured concentrations (mg/L)
2,50 / 2,58
4,50 / 4,69
8,00 / 8,4
14,0 / 14,5
25,0 / 24,9

Details on test conditions:

TEST SYSTEM
- Test vessel: glass beaker
- Material, size, headspace, fill volume: 100 mL
- Aeration: the water surface was covered with a Teflon sheet
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
Elendt M4 and purified water noted in OECD chemical product test guideline No. 211 "Reproduction Inhibition Tests on Daphnia Magna" was used

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours light / 8 hours dark
- Light intensity: 800 lux or less

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : immobilization

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8
- Range finding study
- Test concentrations: 0.250, 2.50, 25.0 (mg/L)
- Results used to determine the conditions for the definitive study: Rate of immobilzation at 48h: 0, 0, 100 (%)

Reference substance (positive control):

yes

Remarks:

see "details on test organisms"

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

2.58 mg/L

Nominal / measured:

meas. (geom. mean)

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

7.19 mg/L

Nominal / measured:

meas. (geom. mean)

Basis for effect:

mobility

Remarks on result:

other: (5.86 - 8.76)

Details on results:

- Mortality of control: 0%

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of DOTG was evaluated with Daphnia in a study performed in accordance with OECD testing guideline 202 and GLP requirements.

EC50-48 h was estimated using measured concentrations as being equal to 7.19 mg/L.

Executive summary:

 

The acute toxicity of DOTG was evaluated with Daphnia in a study performed in accordance with OECD testing guideline 202 and GLP requirements. The young daphnids were exposed to nominal test concentrations between 2,50 and 25,0 mg/L under semi-static conditions during 48 hours. The mean measured concentrations were maintained between 80 and 120 % of nominal. EC50-48 h was estimated using measured concentrations as being equal to 7.19 mg/L. Mortality in control, temperatures, pH range and dissolved oxygen concentration were reported and in agreement with the guideline requirements

Description of key information

48h-EC50DOTG = 7,19 mg/L.
Study performed in accordance with:
- OECD testing guideline 202 and 
- GLP requirements. 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

7.19 mg/L

Additional information

The acute toxicity of DOTG to Daphnia magna was assessed according to the OECD 202 guideline (1984), in a GLP study performed by the Japanese Minstry of Environment.

Water quality parameters of temperature, dissolved oxygen and pH were within acceptable limits.

The results of the 48 hour semi-static Daphnia magna toxicity study are summarized below:

DOTG 48h-EC50 = 7,9 mg/L (5.86 -8.76 ; measured value). The no effect level observed was 2.58 mg/L after 48 hours.