1,3-di-o-tolylguanidine

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-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:

A guideline study was conducted according to OECD-TG211 on Daphnia magna reproduction. The test result showed this chemical effected mainly on mortality in daphnid. The test was well conducted and the detail data on the test are available therefore this test is regarded reliable however the NOEC was driven from mortality instead of reproduction. We determined the NOEC of 2.8 mg/L statistically from the mortality instead of the inhibition on reproduction by Fisher's exact test.

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Version / remarks:

(1998)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Three times during the exposure period, each test solution was sampled from each test container in each test group before and after the water was replaced.

0.75 mL was sampled for the control, auxiliary agent control group, 0.0800, 0.250 and 0.800 mg/L groups and mixed with an equal amount of acetonitrile.

1 mL of the 2.50, 8.00 mg/L groups was sampled, and after making a constant volume in 10 mL of the dilution water, 0.75 mL was sampled and mixed with an equal amount of acetonitrile.

Analysis was conducted by LC/MS. The test substance concentration for each test solution was quantified from the ratio to the peak area of the standard solution and the 21 day time weighted mean was determined.

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 solution II was prepared as per the following chart for each level of concentration.

Test Substance Solution I

Amount of test substance sampled: 4000 mg
Constant solution: Dimethylformadehyde
Constant volume: 20 mL
Dissolution method: manual mixed
Test substance concentration: 200 000 mg/L
Preparation Frequency: at the beginning of exposure
Storage conditions: no storage

Test Substance Solution II

Level of concentrations (mg/L): 0.0800 / 0.250 / 0.800 / 2.50 / 8.00

Test substance sampled (test substance solution I sampled, µL) : 16 (80) / 5 (250) / 160 (800) / 500 (2500) / 1600 (8000)
Constant solution: Dimethylformadehyde
Constant volume: 20 mL
Dissolution method: manual mixed
Test substance concentration (mg/L): 30 / 95 / 300 / 950 / 3000
Preparation Frequency: at the beginning of exposure
Storage conditions: room temperature


100µL of each test substance solution II was sampled and the test solution was kept at a constant volume of 1.0L with the dilution water (auxiliary agent concentration: 100µL/L). 80mL was placed in each of the 10 test containers in a concentration group.

The control group involved only the dilution water, and the auxiliary agent control group contained only the auxiliary agent (auxiliary agent concentration: 100µL/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 immobilization tests were conducted on the standard substance (potassium bichromate, special grade) on a regular basis (approximately every 6 months), and the sensitivity of the test substrate was investigated. The 50% effective immobility concentration (EC50) in a 48 hour period after June 1998 was as follows. This value is nearly identical to the EiC50 values (after June 1998, n=8) for this laboratory.
Mean value ± standard deviation = 0.75 ± 0.17mg/L, n=10
(Minimum value ~ maximum value = 0.57 ~ 1.02mg/L)

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

7) Breeding Conditions of Parent Daphnia Magna to Produce Test Organisms
Breeding Water: Dilution water (refer to 3.2)
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: 4/29/2003~5/20/2003
Mortality Rate of Parents for 2 Weeks Prior to Start of Exposure: <20%
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:

21 d

Hardness:

approximately 250 mg/L (CaCO3 conversion)

Test temperature:

19.7 - 20.6°C

pH:

7.4 - 8.7

Dissolved oxygen:

7.2 - 8.8 mg/L

Nominal and measured concentrations:

nominal: 0.0800, 0.250, 0.800, 2.50, 8.00 mg/L
measured: 0.0891, 0.276, 0.881, 2.84, 8.96 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 100mL glass beaker
- Type (delete if not applicable): covererd with a teflon sheet
- Material, size, headspace, fill volume: 80 mL
- Renewal rate of test solution (frequency/flow rate): once per day
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10
- No. of vessels per vehicle control (replicates): 10

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Elendt M4 and purified water (description in OECD guideline)
- Intervals of water quality measurement: 4 times during the exposure period, before and after replacing water

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

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): mortality and mortality rates for parents, first brood production, mean number of cumulative offspring, generation of dormant eggs

VEHICLE CONTROL PERFORMED: yes

RANGE-FINDING STUDY
no range-finding study performed, study conditions were determined from the acute toxicity test

Reference substance (positive control):

yes

Remarks:

see "details on test organisms"

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

2.84 mg/L

Nominal / measured:

meas. (geom. mean)

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

> 2.84 - < 8.96 mg/L

Nominal / measured:

meas. (geom. mean)

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

LC50

Effect conc.:

4.47 mg/L

Nominal / measured:

meas. (geom. mean)

Basis for effect:

mortality

Remarks on result:

other: 2.84-8.96

Validity criteria fulfilled:

yes

Conclusions:

The toxicity of DOTG on the reproduction of Daphnia magna was evaluated in a study performed in accordance with OECD testing guideline 211 and GLP requirements.

The 21d-NOEC was estimated using measured concentrations as being equal to 2.84 mg/L.

Executive summary:

 

The toxicity of DOTG on the reproduction of Daphnia magna was evaluated in a study performed in accordance with OECD testing guideline 211 and GLP requirements. The animals were exposed to nominal test concentrations between 0.08 and 8.0 mg/L under semi-static conditions during 21 days. The mean measured concentrations were maintained between 80 and 120 % of nominal. Water quality parameters of temperature, dissolved oxygen and pH were within acceptable limits. The NOEC was estimated using measured concentrations as being equal to 2.84 mg/L.

Description of key information

21d-NOECDOTG = 2.84 mg/L.
Study performed in accordance with:
- OECD testing guideline 211 and 
- GLP requirements. 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

2.84 mg/L

Additional information

The toxicity of DOTG to the reproduction of Daphnia magna was assessed according to the OECD 211 guideline (1998), 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 21 days semi-static Daphnia magna reproduction toxicity study are summarized below:

DOTG 21d-NOEC = 2.84 mg/L (measured value).