Sodium O,O-diisopropyl dithiophosphate

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

05.10.2012 - 07.08.2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))

GLP compliance:

yes (incl. QA statement)

Remarks:

(Not the chemical analyses)

Test material

Test material information

Constituent 1

Reference substance name:

Sodium O,O-diisobutyl dithiophosphate

EC Number:

258-508-5

EC Name:

Sodium O,O-diisobutyl dithiophosphate

Cas Number:

53378-51-1

Molecular formula:

C8H18NaO2PS2

IUPAC Name:

Sodium O,O-diisobutyl phosphorodithioate

Test material form:

other: 51 % w/w solution in water, stabilized with X % NaOH

Details on test material:

- Substance type: Liquid
- Physical state: Light brown liquid

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
PHYSICO-CHEMICAL PROPERTIES of read-across material
- Boiling point: 107 °C
- Water solubility (under test conditions): > 1000 g/L
- pH 12-14
- log Pow: 1.67

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: (Nominal) 0; 125; 250; 500; 1,000 and 2,000 mg/L
- Sampling method: Samples were collected at test start and at the end of the test for chemical analysis of the test product. Duplicate samples of 12 mL were collected in 20-mL plastic vials for later analysis. Samples from the highest test concentration 2,000 mg/l were analysed as no effects were seen in any of the concentrations. Although duplicate samples were collected, only one of these samples was analysed. The spare samples were discarded after sponsor approved the report.
- Sample storage conditions before analysis: at - 20 ˚C ± 2.0˚C

Test solutions

Vehicle:

no

Details on test solutions:

A stock solution of 2,000 mg/L was prepared by weighing out 2,000 mg of the test product and dissolving it in 1 L of test medium. pH in the stock solutions was 9.2 and was therefore adjusted to 7.9 by adding 0.1 M and 1 M HCl. The test solutions were prepared by diluting the appropriate amounts of stock sollution in test medium.
The test product was tested at the following nominal concentrations: 0 (control); 125; 250; 500; 1,000 and 2,000 mg/L.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Source: A strain of freshwater crustacean Daphnia magna (Straus) Cladocera, Crustacea originally isolated from Langedam (Birkerød, Denmark), have been cultured at DHI since 1979. Animals from this culture were used in the study.
- Age: Young animals (less than 24 hours old)
- Feeding during test
- Food type: Pseudokirchneriella subcapitate
- Frequency: Three times a day by peristaltic pump system

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

254 mg/L expressed as CaCO3.

Test temperature:

20.1 ± 0.1˚C

pH:

7.8

Dissolved oxygen:

98-100%

Nominal and measured concentrations:

Nominal: 1020 mg/L, measured: 1051 mg/L
The chemical analysis of IBP1-Na conducted by Cheminova A/S showed a measured IBP1-Na concentration of 103-106% of the estimated nominal concentration of IBP1-Na. As the analysed concentration was maintained within ± 20% of the nominal concentration, the test product is assumed to be stable in all test concentrations.

Details on test conditions:

TEST SYSTEM
- Material, size, headspace, fill volume: 50 mL glass beakers with 25 mL of test solution
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 6

OTHER TEST CONDITIONS
- Adjustment of pH: pH in the stock soutions was 9.2 and was therefore adjusted to 7.9 by adding 0.1 M and 1 M HCl.

Reference substance (positive control):

yes

Remarks:

K2Cr2O7, CAS no 7778-50-9

Results and discussion

Effect concentrations

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 1 020 mg/L

Nominal / measured:

nominal

Conc. based on:

dissolved

Basis for effect:

mobility

Remarks on result:

other: As the only immobilization was 5% at 1000 mg/L, no significant effect was observed at the tested concentrations of the test product.

Details on results:

- Mortality of control: None
- Other adverse effects control: None

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Mortality: No
- EC50(24h): 1.6 (1.4-1.7) mg/L (This is in the specified range: 0.6-2.1)
- Other: Less than 10% of the control animals were immobilized

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

< 10 of control animals were immobilized. Dissolved ozygen saturation at the end was ≥ 98% in both tests and controls. EC50(24h) = 1.6 mg/L for control substance (K2Cr2O7, CAS no 7778-50-9) which in the specified range (0.6-2.1 mg/L)

Conclusions:

EC50(48h) of the substance, sodium O,O-diisobutyl dithiophosphate, CAS No. 53378-51-1 exceeds 1020 mg/L for Daphnia magna.
Remark: the test solution contains NaOH due to the production method.