Phosphorothioic acid, O,O-bis(2-methylpropyl) ester, sodium salt (1:1)

Short-term toxicity to fish

Administrative data

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18 - 22 June 1991

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Also according to GLP principles.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Sodium O,O-diisobutyl phosphorothioate

EC Number:

610-992-2

Cas Number:

53378-52-2

Molecular formula:

C8 H18 O3 P S . Na

IUPAC Name:

Sodium O,O-diisobutyl phosphorothioate

Test material form:

other: grease-like solid

Specific details on test material used for the study:

- Name of test material (as cited in study report): CT 473-91
- Name: Sodium diisobutyl monothiophoshate
- CAS: 53378-52-2
- Molecular formula: C8H18O3PS.Na
- Molecular weight: 248.26
- Substance type: Amber liquid
- Physical state: Liquid
- Lot/batch No.: SPS-17220
- Storage condition of test material: Store at room temperature in the dark

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The definitive test concentrations were obtained by transferring the appropriate weight of the test compound.
- Controls: Water dilution

Test organisms

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Source: Mt. Lassen Trout Farm in Red Bluff, California, USA
- Lote #: 1191
- Length at study termination (mean, range and SD): 33 ± 2 mm
- Weight at study termination (mean and range, SD): 0.42 ± 0.09 g
- Feeding during test: None

ACCLIMATION
- Acclimation period: 11 days
- Acclimation conditions (same as test or not): Yes
- Type and amount of food: Not fed in the 48 h prior to the start of the test
- Health during acclimation (any mortality observed): No

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test conditions

Hardness:

160-190 mg/L as CaCO3

Test temperature:

12 - 13 °C

pH:

7.9 - 8.3

Dissolved oxygen:

7.6 - 9.2 mg/L

Nominal and measured concentrations:

Nominal
Range-finding test: 1, 10, 32, 56, 100 and 1000 mg/L
Definitive test: Control, 5.6, 10, 18, 32 and 56 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass vessel
- Material, size, headspace, fill volume: Glass with a capacity of 19 L. Filled with 15 L of test water.
- Aeration: No
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 0.28 g per liter

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

18 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Effect concentrations 2

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

30 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 18 - 56 mg/L

Details on results:

- Mortality of control: None
- Other adverse effects control: None
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No
- Effect concentrations exceeding solubility of substance in test medium: No

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The present study was designed to evaluate toxicity of the test substance to fish (Oncorhynchus mykiss), the resulting 96 h LC50 was 30 mg/L and the NOEC was 18 mg/L (as nominal concentrations).

Executive summary:

In a 96-h acute toxicity study conducted according to OECD TG 203 and GLP principles, rainbow trout (Oncorhynchus mykiss) were exposed to the test material at nominal concentrations of 0 (water control), 5.6, 10, 18, 32 and 56 mg/L under static conditions. The NOEC value was 18 mg/L and the LC₅₀ is 30 mg/L (as nominal concentrations). The present toxicity study is classified as reliable without restrictions since it satisfies the guideline requirements for the fish acute toxicity study (OECD 203). However, water concentrations of test compound were not measured.