Polysulfides, di-tert-nonyl

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:

1998

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP, guideline study. Available as an unpublished report. Acceptable with restrictions

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

not specified

GLP compliance:

yes

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
No data reported

Analytical monitoring:

yes

Details on sampling:

Sampled for analysis at 0 and 48 hours.

Vehicle:

no

Details on test solutions:

Preparation: Since polysulfide di-tert-dodecyl is poorly soluble in water; a saturated solution was prepared by vigorously mixing: 100 mg of polysulfide di-tert-dodecyl with dilution water during 23 hours at 20°C (preliminary test) and 2 mg of polysulfide di-tert-dodecyl with dilution water during 68 hours at 20°C (definitive test). After this saturation period, the saturated solution was filtered with a HV 0.45 µm filter. Vehicle, solvent: Ultrapure water. Dilution water was prepared in the laboratory using pure water and salts according to ISO 6341.

Test organisms (species):

Daphnia magna

Details on test organisms:

Strain: Daphnia magna straus strain 5 or A. Source/supplier: Breeding colony was realized in Elendt M7 medium in the laboratory, organisms were selected by sieving. Breeding method: Not available. Age: Less than 24 hours. Feeding: Microscopic algae Raphidocelis subcapitata. Pretreatment: No. Feeding during test: No. Control group: Yes.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

No

Hardness:

200 ± 20 mg/L as CaCO3

Test temperature:

20 ± 1°C

pH:

8.2 ± 0.2

Dissolved oxygen:

9.2 ± 0.3 mg/L

Salinity:

Not applicable

Nominal and measured concentrations:

Series of approximate dilutions of the dissolved item from 6.25% to 100 %. Concentrations: 6.25, 12.5, 25, 50, 100 nominal concentration (% vol), forming a geometric progression with a factor of 2. Measured concentrations were not available, because the analytical method did not allow the determination of the test substance concentration.

Details on test conditions:

Type and source of exposure medium: ultrafiltered water with carbon exchange. Test vessel: 250 mL glass flasks. No of organisms per vessel: 5. No of replicates per concentration: 4. Photoperiod: Incubation of test flasks in darkness.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.1 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mortality

Remarks on result:

other: Limit of quantification

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

< 0.1 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mortality

Remarks on result:

other: Limit of quantification

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

< 0.1 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mortality

Remarks on result:

other: Limit of quantification

Details on results:

An EC50 was not reported only a 5% effect was observed at 24 and 48 hours. The test item was not detected at the limit of detection and quantification of the analytical technique due to its very low solubility, with the limit of detection and quantification for the analytical technique employed being 0.03 and 0.1 mg/L, respectively.

Results with reference substance (positive control):

The sensitivity of the test organism is confirmed by a toxicity test with Potassium dichromate periodically, EC50/24h =1.1mg/L.

Reported statistics and error estimates:

No data reported

Nominal   Measured                Immobile (%)      
conc      Init        Final          
    %      mg/L        24 hr       24 hr    48 hr 
100       <LQ        <LQ             5           5  
50        <LD        <LD             0           5  
25         NA        NA              0           0 
12.5       NA        NA              5           5 
6.25       NA        NA              0           0

Validity criteria fulfilled:

no

Remarks:

The analytical method used in the test did not allow the determination of the substance concentration as the solubility of the substance in the test medium was below the limit of quantification. The stability of the test substance was also not checked.

Conclusions:

The toxicity of polysulfide di-tert-nonyl to aquatic invertebrates has been read across from polysulfide di-tert-dodecyl. At the solubility limit of the test substance, no significant immobilization of the test organisms was recorded after 24 and 48 hours. Therefore the EC50 was determined to be >0.1 mg/L, the limit of quantification of the analytical technique.

Executive summary:

The toxicity of polysulfide di-tert-nonyl to aquatic invertebrates has been read across from polysulfide di-tert-dodecyl. Thiebaud (1998) is a 48 hour, static, freshwater, GLP-compliant test on Daphnia magna, follows EU Method C2. The results indicate that this substance is slightly toxic to aquatic invertebrates at the limit of solubility and the limits of analytical detection. However the level of toxicity cannot be quantified. The validity criteria of the method were not met as the stability of the substance was not checked but the study is considered suitable for use for this endpoint.

Description of key information

The toxicity of polysulfide di-tert-nonyl to aquatic invertebrates has been read across from polysulfide di-tert-dodecyl. At the solubility limit of the test substance, no significant immobilization of the test organisms was recorded after 24 and 48 hours. Therefore the EC50 was determined to be >0.1 mg/L, the limit of quantification of the analytical technique.

Additional information

The toxicity of polysulfide di-tert-nonyl to aquatic invertebrates has been read across from polysulfide di-tert-dodecyl. Thiebaud (1998) is a 48 hour, static, freshwater, GLP-compliant test on Daphnia magna, follows EU Method C2. The results indicate that this substance is slightly toxic to aquatic invertebrates at the limit of solubility and the limits of analytical detection. However the level of toxicity cannot be quantified. The validity criteria of the method were not met as the stability of the substance was not checked but, the study is considered suitable for use for this endpoint.

The results from the daphnia test are considered conservative as the test was conducted at the limit of solubility and physical rather than toxic effects caused by undissolved substances are likely a contributing factor. These aggregates can affect filter feeding organisms and organisms with respiratory surfaces which are exposed to the external water environment. Since filter feeding and respiration usually requires relatively large volumes of water to be passed over the surface of the organ, there is a high potential for aggregates physically to impair their function. Entrapment of Daphnia in surface films of undissolved test substance is a commonly observed phenomenon in ecotoxicological tests.