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Ecotoxicological information

Long-term toxicity to aquatic invertebrates

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Administrative data

Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Nov. 5, 2012-Oct. 16, 2013
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP study done according to OECD Guidelines.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2013
Report Date:
2013

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 211 (Daphnia magna Reproduction Test)
Deviations:
yes
Principles of method if other than guideline:
Deviations from guideline: 1. Daphhnids were fed 0.6 mg C/daphnid/day rather than 0.1-0.2 mg C/daphnid/day. This amount was fed in order to maintain sufficient feed in the system to support acceptable reproduction rates. 2. WAF settling time was 60-90 minutes instead of 60 minutes. This did not affect the results as settling time was at least 60 minutes.
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: liquid

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: all concentrations and controls - taken at initiation, beginning and end of longest renewing cycle each week, and termination
- Sampling method: Collected from mid-depth, and placed in glass vials with 20 uL of sodium azide (1% w/v)
- Sample storage conditions before analysis: refrigerated

Test solutions

Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Prepared every 2-3 days individually. Calculated amount of test substance was added to dilution water, and mixed using a magnetic stir bar on a stir plate. Vortex depth was maintained at 10%, and mixed for 49 hrs. The test solution was then allowed to settle for 60-90 min.
- Evidence of undissolved material (e.g. precipitate, surface film, etc): No evidence of precipitation. Light green coloration of test substances atributed to alga used for feeding.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia magna
- Source: Wildlife International
- Age: <24 hrs
- Feeding during test
- Food type: yeast, cereal grass media, trout chow, green algae, vitamin solution
- Amount: 0.5 mL trout chow, 1.0 mL algae, 0.40 mL vitamin solution
- Frequency: daily

ACCLIMATION
- Acclimation period: 2 weeks
- Health during acclimation (any mortality observed): no signs of disease or ephippia

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES: Transfers made below water surface using wide-bore pipettes.

Study design

Test type:
semi-static
Water media type:
freshwater
Total exposure duration:
21 d

Test conditions

Hardness:
140-148 mg/L CaCO3
Test temperature:
19.9-20.9 degree C
pH:
8.1-8.5
Dissolved oxygen:
6.4-8.6 mg/L
Nominal and measured concentrations:
0.01, 0.1, 1.0, 10.0 mg/L (WAF)
Details on test conditions:
TEST SYSTEM
- Test vessel: 250 mL glass beakers
- Type (delete if not applicable): covered with plastic petri dishes
- Material, size, headspace, fill volume: 200 mL
- Renewal rate of test solution (frequency/flow rate): 2-3 days
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: 40 m deep well water, passed through a sand filter and aerated, then filtered through a 0.45 um filter and sterilized with UV.
- Alkalinity: 176-182 mg/L CaCO3
- Conductivity: 365-409 uS/cm

OTHER TEST CONDITIONS
- Photoperiod: 16 hrs light/8 hrs dark, with 30 minute transition period
- Light intensity: similar to natural sunlight

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): mortality, onset of reproduction (3 times per week), signs of toxicity, body length, dry weight

VEHICLE CONTROL PERFORMED: yes

Results and discussion

Effect concentrationsopen allclose all
Duration:
21 d
Dose descriptor:
other: NOEL
Effect conc.:
10 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Duration:
21 d
Dose descriptor:
other: LOEL
Effect conc.:
> 10 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Duration:
21 d
Dose descriptor:
other: MATL
Effect conc.:
> 10 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Duration:
21 d
Dose descriptor:
EL50
Effect conc.:
> 10 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
immobilisation
Remarks on result:
other: not calculable
Duration:
21 d
Dose descriptor:
EL50
Effect conc.:
> 10 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
reproduction
Remarks on result:
other: not calculable
Details on results:
- Mortality of parent animals: Survival of control was 95%, survival in the 0.10 mg/L group was 80%, and 90% in the 10 mg/L group. 100% survival was seen in the 0.01 and 1.0 mg/L groups.
- No. of offspring produced per day per female: Average of 270 offspring per female throughout the study in the negative control group, and an average of 281, 306, 274, and 303 in each respective treatment group.
- Body length and weight of parent animals: 4.8 mm and 1.11 mg average in negative control. 4.6, 4.8, 4.6, and 4.8 mm, and 1.13, 1.19, 1.11, 0.99 mg in respective test groups. Some daphnids in the 10 mg/L treatment group were excluded from dry weight measurements due to the presence of eggs in brood pouches
- Type and number of morphological abnormalities: Paleness in one daphnid in negative control group on Day 3, normal appearance in all other daphnids throughout the study.
- Type and number of behavioural abnormalities: Lethargy in one daphnid in negative control group on Day 3.
- Time to first brood release or time to hatch: Day 7, 8, or 9
- Other biological observations: One immobile neonate observed in the negative control group and in the 1.0 mg/L group on Day 12.
Reported statistics and error estimates:
No statistical decrease in exposure groups as compared to negative controls (p>0.05). No statistically significant decrease in mean neonate production in any test group (p>0.05) No statistically significant decrease in dry weight or body length (p 0.05).

Any other information on results incl. tables

No test substance was detected in any sample during the analytical monitoring due to the low water solubility of the test substance. Results were therefore reported using the water accommodated fraction (WAF).

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The 21-day EL50 Daphnia magna exposed to Benezene 10-13, alkyl derivatives was >10 mg/L (WAF) for both immobilization and reproduction. The 21-day NOEL for Daphnia magna was 10 mg/L (WAF).
Executive summary:

Daphnia magna were exposed to the test substance, Benzene 10 -13, alkyl derivatives, at concentrations of 0.01, 0.1, 1.0, 10.0 mg/Lfor 21 days. Both immobilization and reproductive parameters were monitored. Due to the low solubility of the test substance, no test substance was detected in the analytical monitoring. The results are therefore reported as a water accommodated fraction (WAF). The 21-day EL50 for Daphnia magna exposed to Benezene 10-13, alkyl derivatives was >10 mg/L (WAF) for both immobilization and reproduction. The 21-day NOEL for Daphnia magna was 10 mg/L (WAF), and the 21 -day LOEL was > 10 mg/L (WAF).