Propanoic acid, 2-[(ethoxythioxomethyl)thio]-, methyl ester

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

Study period:

from 31 october 2000 to 19 july 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

yes

Remarks:

see below. These deviations are supposed not to have affected the results of the study.

Principles of method if other than guideline:

Deviations from the protocol:
The stock solutions were prepared in Tertiary Butyl Alcohol and not in DSWL-E or in ultrapure water.
The temperature in the test was maintained on 24 ± 1 °C and not on 25 ± l °C.
The total amount of test substance as received in Zeist was 3 kg.
According to the information of the sponsor the solubility of the test substance was 351 mg.r1
Spent samples from the spent solutions were not taken after 24 h from the same solutions as sampled at t = 0 h, but were taken at t = 72 h. This was because the results of the samples at t = 24 h were not correct.
The Department of Environmental Toxicology, part of TNO Nutrition and Food Research, has decided to issue reports and protocols under the name of 'TNO Chemistry.

These deviations are supposed not to have affected the results of the study.

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

The actual concentration of Rhodixan A-1 in the exposure media were deterrnined by chemical analysis. Samples of the solvent control and of the exposure media of 0.32, 1.0 and 3.2 mg/l were taken at t = Oh (newly prepared media) and t = 24h (spent media after 24 hours). Because the results of t = 24h were assumed to be incorrect (the reason for this was not clear), new samples of the spent solvent control and the 0.32, 1.0 and 1.8 mg/l spent media were taken at t = 72h. The results of the analysis at t = 24h are not used for calculations. Samples of ca. 30 ml were taken in 40 ml glass vials and transferred to the analytical laboratories of the Residue Analysis Department for chemical analyses.

Vehicle:

yes

Remarks:

Tertiary butyl alcohol (TBA)

Details on test solutions:

DSWL-E was used as a control medium. Tertiary butyl alcohol (TBA) was used as a carrier to dose the test substance. Aliquots of 0.1 ml stock solution containing appropriate amounts of test substance were dosed per litre of dilution water. New stock solutions were prepared daily throughout the test.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name:
- Strain: Brachydanio rerio
- Source: The test organism used was the fresh-water fish species Brachydanio rerio from the commercial hatchery Atlanta, Hellevoetsluis, the Netherlands.
- Age at study initiation (mean and range, SD):
- Length at study initiation (length definition, mean, range and SD): 2.0 ± 0.3 cm
- Weight at study initiation (mean and range, SD): 0.065 ± 0.032 g
- The fish is cultured under the circumstances of the test.
- The fish were not fed during the test.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

no

Hardness:

no data

Test temperature:

23.6 - 24.5°C

pH:

7.9-8.3

Dissolved oxygen:

6.3 mg O2/l

Salinity:

no data

Conductivity:

no data

Nominal and measured concentrations:

0.32, 0.56, 1.0, 1.8 and 3.2 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): closed; the beakers were covered with a watch glass
- Material, size, headspace, fill volume: 2 litre all-glass beakers, each containing 1.5 litre of exposure medium
- Aeration: The exposure media were slightly aerated and replaced daily.
- Type of flow-through (e.g. peristaltic or proportional diluter): no data
- Renewal rate of test solution (frequency/flow rate): yes
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): no data
- No. of vessels per vehicle control (replicates): 1
- Biomass loading rate: no data

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: The dilution water used was DSWL-E prepared from ground water.
- Total organic carbon: 2.3 mg/l
- Particulate matter: no data
- Metals: no data
- Pesticides: no data
- Chlorine: no data
- Alkalinity: no data
- Ca/mg ratio: no data
- Conductivity: no data
- Salinity: no data
- Culture medium different from test medium: DSWL-E was used as a control medium. Tertiary butyl alcohol (TBA) was used as a carrier to dose the test substance.
- Intervals of water quality measurement: no data

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod:16 h light/8 h dark regime with transition periods of ca. 30 minutes in a temperature controlled room.
- Light intensity: no data

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
The dead and living animals were counted and if applicable the dead ones removed after 3, 24, 48, 72 and 96 hours. At the same time the condition (swimming behaviour, colour or any other visually observable morphological or behavioural criterion) of the survivors was compared with that of the control animals.
The effect of a test substance on the survival of animals can be expressed by a quantity denoted as the LC50 ( = _Lethal Çoncentration, 50% ), i.e. the exposure concentration of the substance which would prove lethal to 50% of an infinite population of the exposed animals. The LC50 is qualified according to the duration of exposure.
The effect of a test substance on the survival of animals can also be expressed by a quantity denoted as the LC 100 ( = _Lethal Çoncentration, 100% ), i.e. the lowest exposure concentration of the substance which is lethal to 100% of the exposed animals. The LCI00 is qualified according to the duration of the exposure.
The 'No Observed fffect Çoncentrations' (NOEC values) are the highest concentrations tested showing no effect with regard to survival or condition throughout the exposure time. The NOEC value is qualified according to the duration of exposure and is estimated by comparing effects with regard to survival and condition of the exposed animals with those of the control animals.

VEHICLE CONTROL PERFORMED: yes

RANGE-FINDING STUDY
- Test concentrations: no information
- Results used to determine the conditions for the definitive study: no data

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 1.8 - < 3.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 0.94 - < 1.7 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.52 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

All exposure media were completely clear (visually assessed) throughout the test.
There was no mortality in the control medium at the end of the test. At 3.2 mg/l all animals were dead at the end of the test; at 1.8 mg/l one animal died. All surviving animals were in good condition. The 96h NOEC value for survival and condition is therefore 1.0 mg/l.
The average percentage of the test substance present during the test was estimated to be 52%.
Based on the average percentage of the test substance present during the test, the LC50 is calculated to be between 0.94 mg/l and 1.7 mg/l measured concentrations.

Results with reference substance (positive control):

no data

Reported statistics and error estimates:

no data

Validity criteria fulfilled:

yes

Remarks:

There was no mortality in the control vessel. The dissolved oxygen concentration was above 5.1 mg/l (>= 60% of the air saturation value at 24°C).

Conclusions:

At 1.8 mg/l nominal concentration of Rhodixan A-1 one animal died and at 3.2 mg/l all animals were dead at the end of the test. Based on the average percentage of the test substance present during the test, the LC50 is calculated to be between 0.94 mg/l and 1.7 mg/l measured concentrations. On a worse case approach, the Rhodixan A-1 is considered as very toxic to the aquatic organisms tested.

Executive summary:

Rhodixan A-1 has been tested for acute toxicity to Brachydanio rerio. The study was carried out according to OECD guideline No.203 and Directive 67/548/EEC, Annexe V, test method C.1 and in compliance with Good Laboratory Practices.

 

The test was carried out under semi-static conditions with daily replacement of the exposure media and with 10 fish for the control medium and each concentration. The exposure duration was 96 hours. Stock solutions in Tertiary Butyl Alcohol (TBA) containing the appropriate amounts of the test substance were used to obtain the following nominal concentrations : 0.32 – 0.56 – 1 – 1.8 – 3.2 mg/l.

 

The actual concentration of Rhodixan A-1 in the exposure media was determined by HPLC with UV-detection. Samples of the exposure media were taken for analysis at T=0h just after dosing, and also in the spent media at T=72h just before replacement the test. Based on these analysis, the average percentage of the test substance present during the test was estimated to be 52%.

 

The validity criteria were fulfilled since there was no mortality in the control vessel and the dissolved oxygen concentration was more than 60%. At 1.8 mg/l nominal concentration of Rhodixan A-1 one animal died and at 3.2 mg/l all animals were dead at the end of the test. Based on the average percentage of the test substance present during the test, the LC50 is calculated to be between 0.94 mg/l and 1.7 mg/l measured concentrations. On a worse case approach, the Rhodixan A-1 is considered as very toxic to the aquatic organisms tested.

Description of key information

At 1.8 mg/l nominal concentration of Rhodixan A-1 one animal died and at 3.2 mg/l all animals were dead at the end of the test. Based on the average percentage of the test substance present during the test, the LC50 is calculated to be between 0.94 mg/l and 1.7 mg/l measured concentrations. On a worse case approach, the Rhodixan A-1 is considered as very toxic to the aquatic organisms tested.

Additional information

A GLP-compliant study, scored as Klimisch 1 and flagged as a key study, is available on the Rhodixan A-1; giving a 96h-EC50: 0.94 -1.7 mg/kg (measured concentrations) and revealing that the Rhodixan A-1 is very toxic to fish (TNO, 2001).