Registration Dossier
Registration Dossier
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EC number: 404-310-0 | CAS number: 10591-85-2 PERKACIT TBZTD; PERKACIT TBZTD PDR; PERKACIT TBZTD PDR-D; TBZD
Toxicity to aquatic algae and cyanobacteria
Administrative data
Link to relevant study record(s)
- Endpoint:
- toxicity to aquatic algae and cyanobacteria
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 2010-2011
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 201 (Alga, Growth Inhibition Test)
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
- Analytical monitoring:
- yes
- Details on sampling:
- All samples were analysed directly after sampling without storage.
One sample from the freshly prepared stock solution and the application solution and duplicate samples from the freshly prepared test medium of the only test concentration and the controls (without algae) were taken at the start of the test.
For the determination of the stability of the test item under the test conditions and of the maintenance of the test item concentrations during the test period, duplicate samples from the test medium of the only test concentration and the controls (without algae) were taken at the end of the test (after the 72 hours test period).
The concentrations of the test item were analysed in the duplicate test media samples from the only test concentration and bath sampling times (0 and 72 hours). From the control and solvent control samples only one of the duplicate samples was analysed from each of bath sampling times. - Vehicle:
- yes
- Details on test solutions:
- Before test start a concentrated stock solution of 1.0 g test item/L was prepared by dissolving 10 mg of the test item in 10 mL DMF. This stock solution was shaken for 2 minutes and diluted by the factor of 10 in DMF again to prepare an application solution with a suitable concentration. The solvent additive was chosen based upon its solubility properties and its relative lack of toxicity to algae. Adequate volumes of the application solution were mixed into test water to obtain the test medium of the desired test concentration.
The test medium was prepared just before introduction of the algae - Test organisms (species):
- Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)
- Details on test organisms:
- Pseudokirchneriella subcapitata, Strain No. 61.81 SAG
The algae were supplied by the "Sammlung von Algenkulturen, Pflanzenphysiologisches Institut der Universitat Gëttingen", 37073 Gëttingen, Germany.
The algae were cultivated in the laboratories under standardised conditions according to the test guidelines. - Water media type:
- freshwater
- Limit test:
- yes
- Total exposure duration:
- 72 h
- Test temperature:
- The temperature was measured daily in an Erlenmeyer flask filled with water and incubated under the same conditions as the test flasks.
Water temperature was: 23 to 24 °C - pH:
- The pH was measured in the test medium of the only test item concentration and the controls at the start and the end of the test.
pH was: 8.1 at test start and 8.5 to 8.6 at test end - Nominal and measured concentrations:
- 10 µg test item/L (in 100 µL DMF/L), a solvent control (100 µL DMF/L) and a control
The concentration tested was nominal 10 µg test item/L. Due to the low water solubility limit of the test item no concentrations above the solubility limit of the test item in the used test water was tested. Additionally, a control (test water without addition of the test item and the solvent) and a solvent control (test water without addition of the test item but with 100 µL DMF/L) were tested in parallel. Thus, a limit test in accordance with the OECD Series on testing and assessment No. 23 was performed to demonstrate that the test item has no inhibitory effect on the growth of the test organism up to the solubility limit in the used test water. - Details on test conditions:
- Erlenmeyer flasks of 50 mL volume with 50 mL of test medium.
The light intensity was measured once during the test at 6 positions distributed over the experimental area at the surface of the test media.
Mean light intensity: 5500 lux (range: 5320 to 5720 lux)
Pre-Experiments:
Pre-experiments were performed to determine the solubility of the test item in test water and to select suitable methods for the preparation of a stock solution and the dosage of the test item into the test media.
The first pre-experiment indicated that a 100mg/L solution prepared with DMF lead to a non homogeneous solution. A second pre-experiment was performed at 10, 1.0, 0.1 and 0.01 µg test item/L with the use of DMF as a solvent. No inhibition of algal growth compared to the control. After the confirmation of the water solubility of the test material with the OECD 105 result, it has been decided to perform a limit test at the 10µg/L concentration
Range-Finding Test:
For the determination of the test concentrations range-finding tests were performed.
The test was started by inoculation of a biomass of 5000 algal cells per mL test medium. These cells were taken from an exponentially growing pre-culture, which was set up 3 days prior to the test start under the same conditions as in the test.
The test was perf0rmed with six replicates for the only test concentration and six replicates for the controls. Volumes of 50 mL of algal suspension per replicate were continuously stirred with magnetic stirrers in 50 mL Erlenmeyer flasks. The flasks were covered with glass dishes and incubated in a water bath.
Additionally, one replicate of the only test concentration and of the controls was prepared without algae to provide a "blank" for the spectrophotometrical measurements. The additional replicates were incubated under the same conditions as described above. The blank values were subtracted from the absorption measured in the samples containing algae in order to eliminate absorption caused by test item.
The cell densities in the samples were determined by spectrophotometrical measurement. Therefore defined volumes of the algal suspensions from all replicates and from the blanks were sampled after 24, 48 and 72 hours of exposure, and were not replaced.
The algal cell densities were calculated by subtracting the absorption of the blanks, from each of the measured absorption of the test media (with algae).
The cell densities in a number of samples from one control replicate were counted by microscope after 72 hours of test duration. Out of this control five defined dilutions were prepared and measured spectrophotometricaliy. Based on the counted cell densities and the absorption of the control sample and the dilutions a linear regression was performed for the calculation of the cell densities in all other samples measured spectrophotometricaliy during the test. - Reference substance (positive control):
- yes
- Remarks:
- For the evaluation of the quality of the algae and the experimental conditions the reference item potassium dichromate is tested at least twice a year to demonstrate satisfactory test conditions
- Key result
- Duration:
- 72 h
- Dose descriptor:
- NOEC
- Effect conc.:
- >= 10 µg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Details on results:
- The 72-hour EC50 and the 72-hour EC10 for the parameters growth rate and yield could not be calculated due to the absence of effects of the test item. Therefore the 72-hour EC50 and the 72-hour EC10 was determined to be higher than the limit of solubility of the test item, represented by the test concentration of nominal 10 µg test item/L, the only concentration tested.
The 72-hour NOEC was determined to be at least nominal 10 µg test item/L for the parameters growth rate and yield and the associated 72- hour LOEC was determined to be higher than nominal 10 µg test item/L for bath parameters.
LoD = 0.030µg test item/L
LoQ = 5µg test item/L - Reported statistics and error estimates:
- The 72-hour ErC50 and the 72-hour EyC50, the corresponding EC10 values and their 95 %-confidence limits could not be calculated due to the absence of toxicity of the test item.
For the determination of the 72-hour LOEC and the 72-hour NOEC, the calculated growth rates and yields at each test concentration were tested for significant differences compared to the values of the solvent control by the Student t-test (growth rate, yield), respectively. According to the test guidelines the solvent control was used as the reference for the statistical evaluation since it did not show a significant difference of algal growth compared to the control after 72 hours of test duration.
The software used to perform the statistical analysis was ToxRat Professional, Version 2.1 0.05, ToxRat® Solutions GmbH - Validity criteria fulfilled:
- yes
- Conclusions:
- No effect was observed up to the water solubility limit
- Executive summary:
The influence of TBzTD (Tetrabenzyl thiuram disulfide) on the growth of the freshwater green algae Pseudokirchneriella subcapitata was assessed in a static limit test. The 72-hour NOEC was determined to be at least 10 µg test item/L for the parameters growth rate and yield. The NOEC might even be higher than this concentration, but concentrations in excess of nominal 10 µg test item/L, representing the limit of solubility, have not been tested according to the recommendations of the test guidelines. The 72-hour LOEC and the 72-hour EC50 for the parameters growth rate and yield were clearly higher than 10 µg test item/L. These values could not be quantified due to the absence of toxicity of TBzTD (Tetrabenzyl thiuram disulfide) up to nominal 10 µg test item/L, the concentration representing the limit of solubility.
- Endpoint:
- toxicity to aquatic algae and cyanobacteria
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 2018
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
- Specific details on test material used for the study:
- Storage Conditions at Test Facility: At 20 ± 5 °C, in the dark
- Analytical monitoring:
- yes
- Details on sampling:
- The samples were taken from the biological phase of the study. Collecting, storage and handing over of the samples were the Study Director’s responsibility. The information concerning the samples was provided by the Study Director.
Duplicate samples from the freshly prepared test media of the only test concentration and the control were taken at test start.
For the determination of the stability of the test item under the test conditions and of the maintenance of the test item concentrations during the test period, samples of the test vessels of the only treatment group and the control were taken in duplicate at the end of the test (after the 72 hours test period) by pooling the content of the test beakers of all replicates of the only treatment group.
Furthermore duplicate samples were taken from the additional test vessels after 24 and 48 hours.
All samples were diluted by a factor of 2 with acetonitrile. Additional samples were taken at each sampling time without any sample treatment.
All samples were measured immediately after sampling and additionally after storage.
The concentration of the test item Tetrabenzylthiurame disulfide (TBzTD) were measured in all duplicate test medium samples and in the additional samples from all sampling times. - Vehicle:
- no
- Details on test solutions:
- Due to the low limit of water solubility of the test item Water accommodated Fraction (WAF) with a nominal loading rate of 5 mg/L and a control were tested. The geometric mean measured concentration was 86.0 µg test item/L.
In the control, test water was used without addition of the test item.
A supersaturated suspension of 5 mg test item/L was prepared by dissolving 12.8 mg test item into 2560 mL test water by stirring for 24 hours. The suspension was resting for 30 minutes, so insoluble test item separated. The test item was floating on the surface. The middle water phase was extracted. The test medium was prepared just before introduction of the algae (= start of the test).
Appearance of the Test Item: there were no remarkable observations - Test organisms (species):
- Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)
- Details on test organisms:
- Pseudokirchneriella subcapitata (KORSHIKOV), Strain No. 61.81 SAG, formerly known as Selenastrum capricornutum, and recently renamed as Raphidocelis subcapitata (KORSHIKOV)
The algae were supplied by the „Sammlung von Algenkulturen, Albrecht-von-Haller-Institut für Pflanzenwissenschaften, Universität Göttingen", 37073 Göttingen, Germany.
The algae were cultivated in the laboratories of ibacon under standardised conditions according to the test guidelines. - Test type:
- static
- Water media type:
- freshwater
- Limit test:
- yes
- Total exposure duration:
- 72 h
- Hardness:
- -
- Test temperature:
- The temperature was measured daily in an Erlenmeyer flask filled with water and incubated under the same conditions as the test flasks.
Water temperature was: 21 to 22 °C - pH:
- The pH was measured in all test item concentrations and the control at the start and the end of the test.
pH was: 8.1 at test start and 9.7 at test end
The pH in the control increased by more than 1.5 units. However, this does not invalidate the tests since the validity criterion was met. - Dissolved oxygen:
- -
- Salinity:
- -
- Conductivity:
- -
- Nominal and measured concentrations:
- Nominal concentration: 5 mg/L
Measured concentration: 0,086mg/L - Details on test conditions:
- - Test units
Erlenmeyer flasks of 50 mL volume of test medium containing as much test medium as possible of at least 50 mL (i.e. the remaining head space was reduced to a technical possible minimum of some mL), kept closed during the whole period of the study with a conical glass stopper to avoid loss of the test item due to volatilisation.
Each test unit was uniquely identified with the serial number of the study, treatment and replicate number.
- Test conditions
Light Regime: Continuous illumination
Light Intensity: The light intensity was measured once during the test at 6 positions distributed over the experimental area at the surface of the test media.
Mean light intensity: 7975 lux (7770 to 8170 lux)
Pre-experiments were performed to determine a suitable concentration range and to establish suitable methods to prepare the test solutions. Since the use of solvent should be avoided three replicates of a dispersion of 5 mg test item/L (high above solubility limit), which were stirred for 96 hours (WAF = Water accommodated fraction) were prepared. We took from each replicate duplicate samples after 24, 72 and 96 hours (6 samples per sampling point). Before sampling we stopped stirring for ca 30min to let the non-dissolved test item separate from the bulk phase in the middle of the flask, from where the samples for the analytics were taken. Results are attached below.
- Course of the test
* Introduction of Algae:
The test was started (0 hours) by inoculation of a biomass of 5000 algal cells per mL test medium. These cells were taken from an exponentially growing pre-culture, which was set up 4 days prior to the test start under the same conditions as in the test.
*Replicates: The test was performed with six replicates of the only test concentration and six replicates in the control. Volumes of at least 50 mL of algal suspension per replicate were continuously stirred with magnetic stirrers in 50 mL Erlenmeyer flasks. The flasks were covered with glass stoppers with a head space reduced to a minimum and incubated in a water bath. The flasks were placed in a random order and were repositioned each day to minimize differences in test conditions.
*Additional Vessels for Analytical Samplings: Two additional replicates of the test item concentration and the control were set up for analytical dose verification after 24 and 48 hours. These additional replicates were incubated under the same conditions as described above.
*Blanks: Additionally, one replicate of the only test concentration and of the control was prepared without algae to provide a "blank" for the spectrophotometric measurements. The additional replicates were incubated under the same conditions as described above. The blank values were subtracted from the absorption measured in the samples containing algae in order to eliminate absorption caused by the test item.
*Exposure Time: 72 hours
*Determination of the Cell Density: The cell density on each observation time was determined by spectrophotometric measurement. Therefore, defined volumes of the algal suspensions from all replicates and from the blanks were sampled after 24, 48 and 72 hours of exposure, and were not replaced. The algal cell densities were calculated by subtracting the absorption of the blanks, from each of the measured absorption of the test media (with algae).
Based on the counted cell densities and the absorption from an algal suspension and its dilutions, a linear regression was performed for the calculation of the cell densities of the replicates during the test. - Reference substance (positive control):
- yes
- Key result
- Duration:
- 72 h
- Dose descriptor:
- EC50
- Effect conc.:
- > 86 µg/L
- Nominal / measured:
- meas. (geom. mean)
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Key result
- Duration:
- 72 h
- Dose descriptor:
- EC10
- Effect conc.:
- > 86 µg/L
- Nominal / measured:
- meas. (geom. mean)
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Key result
- Duration:
- 72 h
- Dose descriptor:
- NOEC
- Effect conc.:
- >= 86 µg/L
- Nominal / measured:
- meas. (geom. mean)
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Details on results:
- Analytical Results:
The quantification of the test item Tetrabenzylthiurame disulfide (TBzTD) in the test samples was performed using liquid chromatography with MS/MS detection.
The concentrations of the test item were determined in the duplicate test media samples from the only test concentration (water accommodated fraction (WAF) with nominal loading rate of 5 mg/L) and the duplicate control samples from all sampling times. The geometric mean measured value is 86.0 µg test item/L in the water accommodated fraction (WAF) with nominal loading rate of 5 mg/L.
Despite clear solutions, since the measured conentrations are well above the water solubility of the test material, undissolved particles may have contributed to these results.
Tabulated data on the algal biomass is available in attachment - Results with reference substance (positive control):
- see table "Results of the Most Recent Test withPseudokirchneriella subcapitata performed with the Reference Item Potassium Dichromate in July 2017"
- Validity criteria fulfilled:
- yes
- Conclusions:
- - Validity Criteria of the Study
Cell Density Increase in Control Cultures: 147.5-fold increase within 72 hours and thus, the validity criterion was met.
Coefficient of Variation of Sectional (Daily) Growth Rates in Control Cultures: 33.2 % and thus, the validity criterion was met.
Coefficient of Variation of Average Growth between Control Replicates: 0.5 % and thus, the validity criterion was met.
The influence of Tetrabenzylthiurame disulfide (TBzTD) on the growth of the freshwater green algae Pseudokirchneriella subcapitata was assessed in a limit test according to the OECD 201 technical guideline with a Water Accomodated Fraction (WAF) prepared at a nominal concentration of 5 mg/L (geometric mean = 0.86µg/L) .
All reported results refer to geometric mean concentrations, since the test item concentrations were not within ± 20% of the measured initial concentrations during the test.
The 72-hour EyC50 was calculated to be > 86.0 µg test item/L and the ErC50 > 86.0 µg test item/L. The 72-hour EyC10 was calculated to be > 86.0 µg test item/L and the ErC10 > 86.0 µg test item/L. The 72-hour NOEyC was determined to be >= 86.0 µg test item/L and the associated 72-hour LOEyC of > 86.0 µg test item/L. The 72-hour NOErC was determined to be >= 86.0 µg test item/L and the associated 72-hour LOErC is > 86.0 µg test item/L. - Executive summary:
The influence of Tetrabenzylthiurame disulfide (TBzTD) on the growth of the freshwater green algae Pseudokirchneriella subcapitata was assessed in a limit test according to the OECD 201 technical guideline with a Water Accomodated Fraction (WAF) prepared at a nominal concentration of 5 mg/L (geometric mean = 0.86µg/L) .
All reported results refer to geometric mean concentrations, since the test item concentrations were not within ± 20% of the measured initial concentrations during the test.
- 72-hour ErC50 > 86.0 µg test item/L
- 72-hour ErC10 > 86.0 µg test item/L
- 72-hour NOErC >= 86.0 µg test item/L .
Referenceopen allclose all
- Algal Cell Densities during the Test Period of 72 Hours
| Density of algal cells [104/mL] after concentration | |||
Nominal concenration [µg test item/L] | Flask No. | 24 hours | 48 hours | 72 hours |
Contrai | 1 | 2.822 | 20.235 | 62.651 |
| 2 | 2.599 | 17.668 | 53.052 |
| 3 | 2.264 | 19.454 | 54.838 |
| 4 | 2.487 | 19.342 | 63.990 |
| 5 | 2.599 | 18.449 | 54.391 |
| 6 | 2.152 | 17.556 | 55.619 |
| m | 2.487 | 18.784 | 57.423 |
| s | 0.245 | 1.071 | 4.663 |
Solvent contrai | 1 | 2.599 | 15.993 | 57.963 |
| 2 | 2.487 | 17.668 | 53.163 |
| 3 | 2.376 | 17.221 | 55.061 |
| 4 | 3.157 | 18.784 | 65.442 |
| 5 | 2.822 | 14.989 | 60.865 |
| 6 | 2.822 | 17.333 | 57.740 |
| m | 2.711 | 16.998 | 58.372 |
| s | 0.282 | 1.330 | 4.356 |
10 | 1 | 2.934 | 18.337 | 57.182 |
| 2 | 2.934 | 16.998 | 55.284 |
| 3 | 2.487 | 17.110 | 59.526 |
| 4 | 2.711 | 17.779 | 54.838 |
| 5 | 2.934 | 16.105 | 64.102 |
| 6 | 3.045 | 18.114 | 59.414 |
| m | 2.841 | 17.407 | 58.391 |
| s | 0.205 | 0.831 | 3.426 |
m: mean value; s: standard deviation
At test start 5000 algal cells/mL were incubated
- Growth rates duriug the Test Period of 72 Hours
| Growth rates µ [1/day] after concentration | |||
Nominal concentration [µg test item/L] | Flask No. | 0 - 24 hours | 0 - 48 hours | 0- 72 hours |
Control | 1 | 1.731 | 1.850 | 1.610 |
| 2 | 1.648 | 1.782 | 1.555 |
| 3 | 1.510 | 1.831 | 1.566 |
| 4 | 1.604 | 1.828 | 1.617 |
| 5 | 1.648 | 1.804 | 1.563 |
| 6 | 1.460 | 1.779 | 1.571 |
| m | 1.600 | 1.812 | 1.580 |
| s | 0.099 | 0.029 | 0.027 |
Solvent control |
| 1.648 | 1.733 | 1.584 |
| 2 | 1.604 | 1.782 | 1.556 |
| 3 | 1.558 | 1.770 | 1.567 |
| 4 | 1.843 | 1.813 | 1.625 |
| 5 | 1.731 | 1.700 | 1.601 |
| 6 | 1.731 | 1.773 | 1.583 |
| m | 1.686 | 1.762 | 1.586 |
| s | 0.103 | 0.040 | 0.025 |
10 | 1 | 1.769 | 1.801 | 1.580 |
| 2 | 1.769 | 1.763 | 1.569 |
| 3 | 1.604 | 1.766 | 1.593 |
| 4 | 1.690 | 1.786 | 1.566 |
| 5 | 1.769 | 1.736 | 1.618 |
| 6 | 1.807 | 1.795 | 1.593 |
| m | 1.735 | 1.775 | 1.586 |
| s | 0.075 | 0.024 | 0.019 |
m: mean value; s: standard deviation
- Results for the Determination of the Test Item in the Test Sampies
sample description age | test item found | calculated test item |
nominal |
% of |
arithmetic | ||||
[µg test item/L] | day | [h] | [µg a.i.!L]' | D.F. | [µg a.i./L]I | [µg a.i.lLl1 | nominal 2 | mean |
|
contre! | 0 | 0 | <LOD | 2 | n.a. | 0.000 | n.a. | n.a. |
|
contre! | 3 | 72 | <LOD | 2 | n.a. | 0.000 | n.a. | n.a. |
|
solvent contre! | 0 | 0 | <LOD | 2 | n.a. | 0.000 | n.a. | n.a. |
|
solvent contre! | 3 | 72 | <LOD | 2 | n.a. | 0.000 | n.a. | n.a. |
|
10 | 0 | 0 | 4.766 | 2 | 9.532 | 10.000 | 95 |
|
|
10 | 0 | 0 | 4.687 | 2 | 9.373 | 10.000 | 94 | 95 |
|
10 | 3 | 72 | 1.700 | 2 | 3.399 | 10.000 | 34 |
|
|
10 | 3 | 72 | 1.538 | 2 | 3.076 | 10.000 | 31 | 33 |
|
geometric mean value (n=2)3: 55
1 The tabulated results represent rounded results calculated on the exact raw data
2 The results represent rounded values
3 The results are calculated from arithmetic mean recoveries ofboth sampling times LOD: Limit of Detection = 0.030 µg test item/L
n.a.: not applicable
RSD: Relative Standard Deviation D.F.: Dilution factor
- Appearance of the Test Item in the Test Media
Geometric mean [µg test item/L] | 0 hours | 24 hours | 48 hours | 72 hours |
10 | 0 | 0 | 0 | 0 |
Abbreviations:
0: No remarkable observations, clear test medium
1: Colouration caused by the test item
2: Turbidity caused by the test item
3: Inhomogeneous dispersion if the test item
4:precipitation of the test item
5: Test item at the surface
6: Test item lying at the bottom of the test vessel
- Algal Cell Densities during the Test Period of 72 Hours
Geometric mean measured concentration | Flask | Density of algal cells [10000/mL] after
| ||
[µg test item/L] | No. | 24 hours | 48 hours | 72 hours |
Control | 1 | 1.446 | 11.895 |
70.682 |
| 2 | 1.446 | 12.276 | 73.536 |
| 3 | 1.446 | 12.846 | 74.963 |
| 4 | 1.446 | 11.515 | 73.536 |
| 5 | 1.446 | 12.846 | 74.759 |
| 6 | 1.446 | 12.656 | 74.963 |
| m | 1.446 | 12.339 | 73.740 |
| s | 0.000 | 0.547 | 1.641 |
86.0 | 1 | 1.257 | 12.276 | 72.109 |
| 2 | 1.257 | 12.276 | 72.517 |
| 3 | 1.446 | 13.988 | 77.816 |
| 4 | 1.257 | 12.846 | 73.128 |
| 5 | 1.067 | 13.417 | 74.963 |
| 6 | 1.446 | 13.037 | 74.147 |
| m | 1.288 | 12.973 | 74.113 |
| s | 0.143 | 0.666 | 2.096 |
m: mean value; s: standard deviation
At test start 5000 algal cells/mL were incubated
- Growth rate during the Test Period of 72 Hours
Geometric mean measured concentration
| Flask |
Growth rates µ [1/day]
| ||
[µg test item/L] | No. | 0 - 24 hours | 0 - 48 hours |
0 - 72 hours
|
Control | 1 | 1.062 | 1.585 | 1.650 |
| 2 | 1.062 | 1.600 | 1.664 |
| 3 | 1.062 | 1.623 | 1.670 |
| 4 | 1.062 | 1.568 | 1.664 |
| 5 | 1.062 | 1.623 | 1.669 |
| 6 | 1.062 | 1.616 | 1.670 |
| m | 1.062 | 1.603 | 1.664 |
| s | 0.000 | 0.022 | 0.008 |
| ||||
86.0 | 1 | 0.922 | 1.600 | 1.657 |
| 2 | 0.922 | 1.600 | 1.659 |
| 3 | 1.062 | 1.666 | 1.682 |
| 4 | 0.922 | 1.623 | 1.662 |
| 5 | 0.758 | 1.645 | 1.670 |
| 6 | 1.062 | 1.630 | 1.666 |
| m | 0.941 | 1.627 | 1.666 |
| s | 0.113 | 0.026 | 0.009 |
m: mean value; s: standard deviation
- Influence of Tetrabenzylthiurame disulfide (TBzTD) on the Growth of Pseudokirchneriella subcapitata
Parameter | Yield | Growth rate |
| [µg test item/L] | [µg test item/L] |
|
|
|
72-hour EC50 | > 86.0 | > 86.0 |
95 % conf. interval | n.d. | n.d. |
|
|
|
72-hour EC20 | > 86.0 | > 86.0 |
95 % conf. interval | n.d. | n.d. |
|
|
|
72-hour EC10 | > 86.0 | > 86.0 |
95 % conf. interval | n.d. | n.d. |
|
|
|
72-hour NOEC | ≥ 86.0 | ≥ 86.0 |
72-hour LOEC | > 86.0 | > 86.0 |
n.d. = not determinable
Values refer geometric mean measured test concentrations
- Results for the Determination of the Test Item in the Test Samples
Sample Description Sampling day |
Age [h] | Concentration found [µg test item/L]1 |
D.F. | Concentration calculated [µg test item/L]1 |
Control 0 | 0 | <LOD | 2 | n.a. |
Control 0 | 0 | <LOD | 2 | n.a. |
Control 1 | 24 | <LOD | 2 | n.a. |
Control 1 | 24 | <LOD | 2 | n.a. |
Control 2 | 48 | <LOD | 2 | n.a. |
Control 2 | 48 | <LOD | 2 | n.a. |
Control 3 | 72 | <LOD | 2 | n.a. |
Control 3 | 72 | <LOD | 2 | n.a. |
WAF of 5 mg/L 0 | 0 | 50.808 | 2 | 101.616 |
WAF of 5 mg/L 0 | 0 | 47.581 | 2 | 95.163 |
WAF of 5 mg/L 1 | 24 | 45.732 | 2 | 91.464 |
WAF of 5 mg/L 1 | 24 | 43.193 | 2 | 86.385 |
WAF of 5 mg/L 2 | 48 | 60.699 | 2 | 121.398 |
WAF of 5 mg/L 2 | 48 | 50.810 | 2 | 101.620 |
WAF of 5 mg/L 3 | 72 | 20.341 | 2 | 40.681 |
WAF of 5 mg/L 3 | 72 | 21.543 | 2 | 43.087 |
geometric mean value (n=4)2: 86.0
1 The tabulated results represent rounded results calculated on the exact raw data
2 Calculated using mean of duplicates and according to OECD Guidance Document No. 23, Annex 2
LOD: Limit of Detection = 0.07 µg test item/L; LOQ: Limit of Quantification = 12.5 µg test item/L after dilution by factor 2 (corresponding to fortification level of nominal 25 µg test item/L); n.a.: not applicable; RSD: Relative Standard Deviation; D.F.: Dilution factor
- Results of the Most Recent Test with Pseudokirchneriella subcapitata performed with the Reference Item Potassium Dichromate in July 2017
Parameter Yield Growth rate Biomass
(0-72 h) [mg test item/L] [mg test item/L] [mg test item/L]
72-hour EC50 0.415 1.02 0.455
95 % conf. interval 0.394 - 0.437 0.984 - 1.05 0.433 - 0.478
72-hour EC20 0.222 0.555 0.229
95 % conf. interval 0.204 - 0.239 0.525 - 0.584 0.211 - 0.247
72-hour EC10 0.160 0.405 0.160
95 % conf. interval 0.142 - 0.177 0.375 - 0.433 0.144 - 0.177
72-hour NOEC 0.094 0.094 0.094
72-hour LOEC 0.21 0.21 0.21
n.d. = not determinable, values refer to nominal test concentrations
- Appearance of the Test Item in the Test Media
Geometric mean [µg test item/L] | 0 hours | 24 hours | 48 hours | 72 hours |
86.0 | 0 | 0 | 0 | 0 |
Abbreviations:
0: No remarkable observations, clear test medium
1: Colouration caused by the test item
2: Turbidity caused by the test item
3: Test item lying at the bottom of the test vessel
4: Test item at the surface
5: Test item caused foaming
+: Effects were strongly pronounced
Effects in parenthesis were only slightly pronounced
Description of key information
The influence of TBzTD on the growth of Pseudokirchneriella subcapitata
and Desmodesmus subspicatus was assessed in tests
according to the OECD 201 guideline (including two limit tests).
Taken altogether, theses results demonstrate that TBzTD is not hazardous to algae as it does not inhibit algal growth up to its limit of solubility.
The 72-hour ErC50 and the 72-hour NOECr were determined to be at least 86 µg test item/L according to the the study of Börschig, 2018.
Key value for chemical safety assessment
- EC50 for freshwater algae:
- 86 µg/L
- EC10 or NOEC for freshwater algae:
- 86 µg/L
Additional information
The influence of TBzTD (Tetrabenzyl thiuram disulfide) on the growth of the freshwater green algae (Pseudokirchneriella subcapitata and Desmodesmus subspicatus) was assessed in tests according to the OECD 201 guideline (including two limit tests).
Sample purity of the test item used in the study of Buche, 2006 is not in agreement with the substance identity profile of the REACH dossier. Therefore the observed toxicity could be due to unknown impurity present at a high level in the tested item. Although the study is technically valid (i.e., all validity criteria are fulfilled), the results are not relevant for REACH registration.
Furthermore, no toxicity was observed in the other toxicity studies to algae with test items in compliance with the substance identity profile of the REACH dossier.
The 72-hour ErC50 and the 72-hour NOECr were determined to be at least 86 µg test item/L according to the study of Börschig, 2018.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
