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Ecotoxicological information

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:
23 Mar 2018 to 25 May 2018
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Remarks:
Non-GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report Date:
2018

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
other: ISO International Standard 14669
Version / remarks:
ISO International Standard 14669. "Water quality - Determination of acute lethal toxicity to marine copepods (Copepoda, Crustacea)", First edition 1999-04-01.
Deviations:
no
Qualifier:
according to
Guideline:
other: OECD Guideline 23
Version / remarks:
Guidance document on aquatic toxicity testing of difficult substances and mixtures, OECD series on testing and assessment number 23, 2000.
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
Off-white powder
Specific details on test material used for the study:
Purity 98.7 by HPLC, %w/w

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Test Samples
The samples were analyzed on the day of sampling and were diluted in a 3:1 (v:v) ratio with acetonitrile and analyzed.
All solutions containing the test item were protected from light.

Test solutions

Vehicle:
no
Details on test solutions:
2.2.3. Preparation of Solutions
Concentrations were corrected for the purity of the test item using a correction factor of 1.013.
All solutions containing the test item were protected from light.

Stock and Spiking Solutions
Stock solutions of the test item were prepared in acetonitrile at concentrations of 1000 and 2000 mg/L.
Spiking solutions were made up from a stock solution and/or dilutions of this solution. The solvent of the spiking solutions was acetonitrile.

Calibration Solutions
Six calibration solutions in the concentration range of 0.004 - 40 mg/L were prepared in 25/75 (v/v) acetonitrile/natural seawater from two stock solutions.
Quality Control (QC) Samples
3 mL blank medium was spiked with the test item at a target concentration of 0.01 or 100 mg/L.
The QC samples were treated similarly as the test samples (see paragraph 2.2.2 ‘Test Samples’). The samples at the high level were 10-fold further diluted with 25/75 (v/v) acetonitrile/natural seawater to obtain concentrations within the calibration range.
Blank QC samples consisting of blank medium were treated similarly to the QC and test samples.

2.2.4. Sample Injections
Calibration solutions were injected in duplicate. Test samples and QC samples were analyzed
by single injection.

Test organisms

Test organisms (species):
other aquatic crustacea: Tisbe battagliai (Copepoda, Crustacea) (Volkmann-Rocco),
Details on test organisms:
Source Guernsey Sea Farms Ltd., Guernsey, United Kingdom.
Reason for selection This system has been selected as an internationally accepted invertebrate species.
Characteristics 6 ± 2 days old copepodids

Study design

Test type:
static
Water media type:
saltwater
Limit test:
yes
Total exposure duration:
48 h
Post exposure observation period:
24 and 48 hrs

Test conditions

Test temperature:
18-22°C, constant within 2°C.
pH:
8.3
Dissolved oxygen:
>80%
Salinity:
35%
Details on test conditions:
Test vessels All-plastic 24-well plates covered with a lid.
Volume of vessel 3 ml
Number of copepodids 20 per concentration
Loading 5 per vessel containing 2.5 ml of test solution
Light The test was performed in the dark
Aeration No aeration of the test solutions.
Feeding No feeding
Introduction of copepodids 32 minutes after preparation of the test solutions.
Reference substance (positive control):
yes

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
> 44 µg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Key result
Duration:
24 h
Dose descriptor:
LC50
Effect conc.:
> 44 µg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
9. RESULTS
The first combined limit/range-finding test was not valid since mortality in the control was too high (35%). Consequently, the test was repeated and the biological results of the first one were not reported. Analysis of the samples taken in this test showed measured concentrations of 0.0071, 0.067 and 0.71 mg/L in solutions containing 1.0, 10 and 100% of the SS, respectively, at the start of the test. These concentrations decreased below the limit of detection at the end of the test (see Table 2 of the appended Analytical Report).

9.1. Combined Limit/Range-Finding Test
Table 1 shows the responses recorded during the second combined limit/range-finding test.
No mortality was observed in the control throughout the test. At the end of the test, 20% mortality was observed at the two lowest test concentrations, while 67% mortality was observed at the limit concentration. All test conditions were maintained within the limits prescribed by the study plan.
No samples were analysed for determination of actual exposure concentrations.

9.2.1. Measured Concentrations
The results of analysis of the samples taken during the final test are described in Table 3 of the appended Analytical Report.
Samples taken from all test concentrations and the control were analysed. The measured concentrations at the start of the test were respectively 0.017, 0.039, 0.084, 0.19, and 0.41 mg/L in solutions containing 4.6, 10, 22, 46 and 100% of the SS prepared at a loading rate of 100 mg/L. At the end of the test, a concentration of 0.0048 mg/L could be estimated at the highest test concentration, while all the remaining measured concentrations had decreased below the Limit of Detection (LOD; 0.0021 mg/L). Nevertheless, it can be stated that testing was performed at the maximum soluble concentration of test item in test medium. Based on these results, effect parameters were based on average exposure concentrations (see Table 2).

9.2.2. Mortality
Table 3 shows the responses recorded during the final test. No biologically relevant mortality (i.e. >10%) was observed in the control and at the four lowest test concentrations throughout the test. It should be noted that 10% mortality is allowed in the control and, therefore, effects ≤10% are considered to be biologically not relevant. At the end of the test, 15% mortality was observed at the highest test concentration.
Results with reference substance (positive control):
9.2.3. Reference Control
At the end of the test 25% mortality was observed in the reference control (see Table 3). Since the effect in this treatment should be between 20 and 80% it was concluded that the batch copepodids used for this test showed normal sensitivity to Zinc sulphate heptahydrate.

9.2.5. Experimental Conditions
The results of measurement of pH, salinity and oxygen concentrations (mg/L) are presented in Table 5. These test conditions remained within the limits prescribed by the study plan.
The temperature continuously measured in a temperature control vessel remained stable at 20°C during the test, and complied with the requirements as laid down in the study plan (18-22°C, constant within 2°C).
Reported statistics and error estimates:
The first combined limit/range-finding test was not valid since mortality in the control was too high (35%).

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
The study met the acceptability criteria prescribed by the study plan and was considered valid.
Conclusions:
In conclusion, under the conditions of the present study with Tisbe battagliai the 48h-LC50 exceeded an average exposure concentration of 44 μg/L, being considered as the maximum soluble concentration of test item in test medium.