MoVNbTe mixed oxide

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:

from 2021-09-24 to 2021-10-07 with the definitive exposure phase from 2021-09-28 to 2020-09-30

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

(2004)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Test item Mo10V3TeNbO42
Batch number EX.14402.600
CAS No. 146569-48-4
Active ingredient Niobium trivanadium decamolybdenum tellurium dotetracontaoxide
Purity 87.6 %
Mo content 47.87 % (stoichiometric content)
Water solubility of Mo 11.498 mg/L (at pH 8.5, after 4 d shaking at 100 rpm of 100 mg/L Mo10V3TeNbO42; Affolter, 2020)
Water solubility < 0.2 g/L practically insoluble
Stability under test
conditions Not specified
Appearance Black solid powder
Expiry date 2026-03-10
Recommended storage Store tightly closed, cool and dry / 20 °C

Analytical monitoring:

yes

Remarks:

via element analysis of molybdenum

Details on sampling:

The test item was determined via element analysis of molybdenum, processed at the Test Site. Test item samples were labelled with the test number, the concentration, the code for the sampling times, the replicate number, the date and the sampler, according to the test facility SOP and delivered to the Test Site for the analytical delegated phase. A full chain of custody was maintained. A description of the method, the results of the method validation and the results of analytical determination are given in the Phase Report (see Annex II).

Sampling schedule
All concentration levels and the control were analysed via element analysis of molybdenum in the fresh media at the start of exposure and at the renewal of the test solutions (0 and 24 hours) as well as in the 24-hours old media at the renewal and at the end of the exposure (24 and 48 hours).

All samples were taken in duplicate. The samples were stored at the test facility in a fried (2 – 8 °C). The first replicate was shipped pooled to the test site at the end of the exposure phase for analysis, respectively. The principle investigator was informed by the study director prior to shipment. Analysis were performed as described in the phase plan.

Vehicle:

no

Details on test solutions:

Preparation of the Saturated solution
A saturated solution with a nominal loading rate of 100 mg test item/L was prepared once at room temperature 96 ± 1 hour prior to the start of the exposure and the renewal. An appropriate amount of the test item was weighed out and transferred with demineralized water to a glass flask with demineralized water. The saturated solution was stirred with approximately 1100 rpm for 96 ± 1 hour at room temperature. After a separation phase of 30 minutes, the saturated solution was removed by siphoning from the approximate center of the glass bottle. Undissolved particles were removed by membrane filtration (membrane filter 0.45 µm, RC, MACHEREY-NAGEL). The filter was saturated in order to avoid adsorption during the filtration. The first 25 mL of the filtrate were discarded. The filtration was interrupted for 15 minutes to allow for adsorption and saturation of the filter material with dissolved test item. Thereafter, the filtration was continued. The next 25 mL were discarded. The following filtrate, i.e. the saturated solution, was used in the test. During filtration, the filter was always kept covered. The saturated solution was checked via laser beam (Tyndall effect) for undissolved test item. No presence of undissolved test item was observed. Then the components of the dilution water were added to the saturated solution.

Preparation of the test solutions
Out of the saturated solution 5 concentration levels were tested in a geometric series with a dilution factor of 2.2: 4.27 – 9.39 – 20.7 – 45.5 – 100% of the saturated solution. The dilution levels were selected based on the results of a non-GLP preliminary range finding test.

Test organisms (species):

Daphnia magna

Details on test organisms:

Daphnia magna STRAUS, obtained from continuous laboratory cultures.

Reason for the selection of the test system
Daphnia magna is the preferred species in accordance with the test system guideline and is bred at the test facility.

Origin
Institut für Wasser-, Boden- und Lufthygiene (WaBoLu), 14195 Berlin, Germany

Breeder
Noack Laboratorien GmbH, Käthe-Paulus-Str. 1, 31157 Sarstedt, Germany

Culture
In glass vessels (2 - 3 L capacity) with approximately 1.8 L culture medium, at 20  2 °C, in an incubator, 16 hours illumination; light intensity of max. 1500 lx

Culture medium Elendt M4, according to OECD 202, Annex 3 (2004) is used.

Feeding of the culture stocks
The daphnids were fed at least 5 times per week ad libitum with a mix of unicellular green algae, e.g. Pseudokirchneriella subcapitata and Desmodesmus subspicatus. The algae were cultured at the test facility.

Test type:

semi-static

Water media type:

freshwater

Remarks:

ISO Test Water (according to OECD 202, Annex 3)

Limit test:

no

Total exposure duration:

48 h

Hardness:

See "Any other information on results incl. tables" below.

Test temperature:

See "Any other information on results incl. tables" below.

pH:

See "Any other information on results incl. tables" below.

Dissolved oxygen:

See "Any other information on results incl. tables" below.

Conductivity:

See "Any other information on results incl. tables" below.

Nominal and measured concentrations:

Out of the saturated solution 5 concentration levels were tested in a geometric series with a dilution factor of 2.2: 4.27 – 9.39 – 20.7 – 45.5 – 100% of the saturated solution.

Details on test conditions:

Control
Dilution water without test item incubated under the same conditions as the test groups. The control solution was prepared without test item following the same method as specified for the saturated solution.

Reference Test
A reference test with potassium dichromate is conducted as an acute acute immobilization test (acc. to AQS P 9/2 and OECD 202) in Elendt M4 medium under static conditions with a test duration of 24 hours once per quarter in order to prove the validity of the test system and test conditions at the test facility.

Test method
The study was performed under semi-static conditions with a renewal of the test solutions after 24 hours.

Test duration 48 hours
 
Test vessels
Glass beakers (4 (ID) x 7 (H) cm), 50 mL capacity, loosely covered with watch glasses

Test volume 20 mL

Dilution water ISO Test Water (according to OECD 202, Annex 3)

Number of daphnids and replicates
20 daphnids, divided into 4 replicates, each with 5 daphnids, were used for the limit concentration and the control.

Age of the daphnids at the start of the exposure
Less than 22 hours old daphnids from a healthy stock were used for the study. To achieve this, juvenile daphnids were removed from the culture vessels at the latest 22 hours before the start of the exposure and discarded. The juveniles born within the following period were used for the test after an acclimatization phase of at least 2 hours in the dilution water. No first brood progeny was used for the test.

Acclimatization At least 2 hours in the dilution water

Application
20 g test solution per replicate was weighed out into each test vessel. This corresponds to 20 mL per test vessel. The daphnids were inserted with a small amount of dilution water (start of the exposure) or test solution (renewal of the test solutions) by pipette.

Renewal of the test solutions
The test solutions were renewed after 24 hours. For this purpose, a second set of test vessels was filled with the freshly prepared test solutions and the daphnids were transferred by pipette.

Test temperature (target) 18 - 22 °C, constant within ± 1 °C

Illumination (target) Diffuse light, light intensity of max. 1500 lx

Photoperiod (target) 16/8 hours light/dark cycle

Feeding The daphnids were not fed during the study.

Type and Frequency of Measurements

Biological Parameters

Immobilization and other observations
Immobilization was determined in all groups after 24 and 48 hours. An animal was considered immobile, if it was not able to swim in the water phase within 15 seconds after gentle agitation of the test vessel. Observation of other adverse, sub-lethal effects (e.g. discoloration, abnormal behavior etc.) was done, but none occurred during the course of the study.

Water Quality Parameters

Dilution water
Prior to the start of the exposure (0 hours) and the renewal of the test solutions (24 hours), the water quality parameters (i.e. pH-value, dissolved oxygen concentration, temperature, conductivity and total hardness) of the dilution water were measured.

Test media
At the start of the exposure and at the renewal (0 and 24 hours), the water quality parameters of the fresh media (i.e. pH-value, dissolved oxygen concentration) were measured in one additional replicate (without daphnids) per concentration and the control.
At the renewal and at the end of the exposure (24 and 48 hours), the water quality parameters of the old media were measured in one appropriate replicate (containing daphnids) of each loading rate and the control.
Temperature The incubator temperature (measurement in air with a thermo-hygrograph) was recorded throughout the period of the test.

Criteria for the water quality
• The dissolved oxygen concentration in the 24-hours old media
parameters (target) should be ≥ 3 mg/L in the saturated solution and the control.
• The pH should be in the range of 6 – 9.
• The deviation of the final pH-values (old media) from the initial
values (fresh media) should not exceed 1.5 units.

Reference substance (positive control):

yes

Remarks:

The percentage of immobility for the reference item potassium dichromate (SIGMA-ALDRICH, batch number BCCC1619, purity 100%, CAS RN 7778-50-9) was determined after 24 hours from 2021-07-14 to 2021-07-15.

Key result

Duration:

48 h

Dose descriptor:

EL100

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

24 h

Dose descriptor:

EL100

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

ca. 47 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

24 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

EL10

Effect conc.:

ca. 43.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

24 h

Dose descriptor:

EL10

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

The percentage of immobility, determined in all tested loading rates and in the control after 24 and 48 hours under semi-static conditions and the absolute numbers of immobile daphnids are presented in "Any other information on results incl. tables" below.
All concentrations and the control were colorless and clear throughout the exposure.

Water Quality Parameters

The measured water quality parameters (i.e. pH-value, dissolved oxygen concentration, total water hardness and water temperature) were within the acceptable limits.

The study was performed according to OECD Guideline 202 (2004). The validity criteria were fulfilled.

Results with reference substance (positive control):

The percentage of immobility for the reference item potassium dichromate (SIGMA-ALDRICH, batch number BCCC1619, purity 100%, CAS RN 7778-50-9) was determined after 24 hours from 2021-07-14 to 2021-07-15. For results of the most recent of the monthly performed reference tests, see "Any other information on results incl. tables".

Reported statistics and error estimates:

Methods of evaluation
The EL100 – values (after 24 and 48 hours were estimated empirically from the observed immobilization rates.
All effect levels (EL10 / 50 / 100) are given based on the nominal loading rates of the test item.

ECx-values and statistical analyses
The EL10/50-values after 24 and 48 hours of exposure were calculated by sigmoidal dose response regression with the software GraphPad Prism. The respective 95% confidence limits were calculated from the standard error and the t distribution wherever possible. In the case that the confidence limits could not be calculated by the software, the respective confidence limits were empirically derived from the observation data. All calculations were carried out from the best-fit values with the software GraphPad Prism.
The concentration-effect relationships for immobilization after 48 hours are shown graphically.

Software
All data were computer-processed and rounded for presentation. Consequently, minor variations may occur from the original figures if manual calculations based on the original figures are made subsequently. Calculations were made using the following software:
- GraphPad Prism, GRAPHPAD SOFTWARE, INC.
- Excel, MICROSOFT CORPORATION

Immobilization Rates after 24 and 48 hours of Exposure
(n = 20, divided into 4 replicates with 5 daphnids each)

Saturated solution with a nominal loading of 100 mg/L	IMMOBILIZATION [%]
[%]	24 hours					48 hours
	Replicates					Replicates
	1	2	3	4	MV	1	2	3	4	MV
100	20	0	20	0	10	80	80	80	100	85
45.5	0	0	0	0	0	40	40	20	20	30
20.7	0	0	0	0	0	0	0	0	0	0
9.39	0	0	0	0	0	0	0	0	0	0
4.27	0	0	0	0	0	0	0	0	0	0
Control	0	0	0	0	0	0	0	0	0	0

 

Absolute Numbers of immobile Daphnids after 24 and 48 h of Exposure
(n = 20, divided into 4 replicates with 5 daphnids each)

Saturated solution with a nominal loading of 100 mg/L	Number of immobile Daphnids / Total number of Daphnids
[%]	24 hours					48 hours
	Replicates					Replicates
	1	2	3	4	Sum	1	2	3	4	Sum
100	1 / 5	0 / 5	1 / 5	0 / 5	2 / 20	4 / 5	4 / 5	4 / 5	5 / 5	17 / 20
45.5	0 / 5	0 / 5	0 / 5	0 / 5	0 / 20	2 / 5	2 / 5	1 / 5	1 / 5	6 / 20
20.7	0 / 5	0 / 5	0 / 5	0 / 5	0 / 20	0 / 5	0 / 5	0 / 5	0 / 5	0 / 20
9.39	0 / 5	0 / 5	0 / 5	0 / 5	0 / 20	0 / 5	0 / 5	0 / 5	0 / 5	0 / 20
4.27	0 / 5	0 / 5	0 / 5	0 / 5	0 / 20	0 / 5	0 / 5	0 / 5	0 / 5	0 / 20
Control	0 / 5	0 / 5	0 / 5	0 / 5	0 / 20	0 / 5	0 / 5	0 / 5	0 / 5	0 / 20

 

EC50-Value (with 95% confidence limits) of the Reference Item Potassium dichromate
based on nominal concentrations mg/L, (0 - 24 hours)

	Current Study	Valid Range
EC50	2.00 mg/L	0.6 - 2.4 mg/L, acc. to AQS P 9/2 (02/2000)
95% confidence limits	1.00 – 4.00 mg/L

 

Validity criteria (target)	Result	Valid
The test is unacceptable if more than 10% of the control organisms are immobilized or show other signs of disease or stress, e.g. discoloration or unusual behavior such as trapping on the surface of the water, during the 48-hour test period.	No daphnid	ü
The dissolved O2 concentration in the 24-hours old media at renewal and at the end of the exposure should be ≥ 3 mg/L in all concentration levels and in the control.	≥ 8.06 mg/L	ü

 

Water Quality Parameters in the fresh Media at the Start of the Exposure and at the Renewal
(0 and 24 hours)
(measured in one additional replicate (without daphnids) per concentration and the control)

Saturated solution with a nominal loading of 100 mg/L	0 hours		24 hours
[%]	pH-value	Dissolved	pH-value	Dissolved
		O2 concentration [mg/L]		O2 concentration [mg/L]
100	7.51	7.08	7.58	6.83
45.5	7.55	8.23	7.63	8.10
20.7	7.54	8.64	7.66	8.48
9.39	7.53	8.80	7.69	8.70
4.27	7.48	8.89	7.75	8.74
Control	7.46	8.92	7.77	8.72

 

Water Quality Parameters in the 24-hours old Media at the Renewal (24 hours) and at the End of the Exposure
(measured in one replicate (containing daphnids) per concentration and the control)

Saturated solution with a nominal loading of 100 mg/L	24 hours			48 hours
[%]	pH-value	Dissolved	Replicate	pH-value	Dissolved	Replicate
		O2 concentration	number		O2 concentration	number
		[mg/L]			[mg/L]
100	7.30	8.72	1	7.86	8.78	4
45.5	7.36	8.64	1	7.90	8.83	1
20.7	7.51	8.62	1	7.95	8.83	4
9.39	7.41	8.62	1	8.01	8.76	4
4.27	7.57	8.58	1	8.07	8.61	4
Control	6.82	8.48	1	8.20	8.06	4

 

 

Water Quality Parameters of the Dilution Water at the Start of the Exposure and at the Renewal (0 and 24 hours)

Dilution water	pH-Value	Dissolved	Temperature	Conductivity	Total hardness
dated:		O2 concentration
		[mg/L]	[°C]	[µS/cm]	[mg CaCO3/L]
0 hours	7.77	8.77	20.3	627	261
24 hours	7.85	8.82	21.1	621	237

 

Preliminary Range Finding Test (non-GLP)

A non-GLP preliminary range finding test was conducted at the test facility under semi-static conditions over a period of 48 hours with three nominal test item concentrations of 1, 10 and 100% of the saturated solution prepared with dilution water.
A saturated solution with a nominal loading rate of 100 mg/L. The saturated solution was prepared as described. Out of this saturated solution two dilution levels were prepared with the concentrations 1.00 and 10.0% of the saturated solution. The saturated test item solution showed no Tyndall effect. The saturated solution and the dilution levels were visually clear and colorless throughout the exposure period.
In the range finding test, two replicates per concentration level and control, each with five daphnids, were tested. The preliminary range finding test was conducted under diffuse light conditions (light intensity of max. 1500 lx, 16/8 hours light/dark cycle).

Results of the Range Finding Test (0 - 72 hours)

Saturated solution	IMMOBILIZATION [%]
[%]	24 hours			48 hours
	Replicates			Replicates
	1	2	MV	1	2	MV
100	20	0	10	100	80	90
10	0	0	0	20	40	30
1	0	0	0	0	0	0
Control	0	0	0	0	0	0

 

Measured Exposure Mo Concentrations during the non-GLP Preliminary Range Finding Test
Determination of the molybdenum concentration via element analysis of Mo

Sampling date	Fresh media,	Old media,	Fresh media,	Old media,
	0 hours	24 hours	24 hours	48 hours
Saturated solution	Mo of the test item Mo10V3TeNbO42
[%]	Measured concentration	Measured concentration	Measured concentration	Measured concentration
	[mg/L]	[mg/L]	[mg/L]	[mg/L]
100	11.3	11.2	11.5	11.7
10.0	1.11	1.10	1.16	1.15
1.00	0.114	0.109	0.113	0.114
Control	< LCL		< LCL

 

Results

The purpose of this study was the determination of the concentration of molybdenum in test medium with dissolved test item Mo10V3TeNbO42 prepared by Noack Laboratorien (study no. SO21064 / DAI19517). Therefore, the provided sample solutions were acidified and analysed by inductively coupled plasma and optical emission spectrometry (ICP-OES).

The validity of the applied analytical method was proven (specificity, linearity, limit of quantification (LOQ), accuracy and precision). The validation results meet the specifications according to SANTE/2020/12830, Rev.1.

The mean results of the provided sample solutions are summarized in the following table:

Date	Sample	Sample description	Mean measured	Recovery^1)	Recovery^2)
	code		Mo concentration
[yyyy-mm-dd]			[mg/L]	[%]	[%]
28.09.2021	A0	Control	< 0.01	-	-
29.09.2021	E0	Control	< 0.01	-	-
29.09.2021	A1	Control	< 0.01	-	-
30.09.2021	E1	Control	< 0.01	-	-
28.09.2021	A0	4.27% (100 mg/L)	0.4955	100.92	24.24
29.09.2021	E0	4.27% (100 mg/L)	0.4944	100.70	24.19
29.09.2021	A1	4.27% (100 mg/L)	0.4629	94.28	22.65
30.09.2021	E1	4.27% (100 mg/L)	0.4676	95.24	22.88
28.09.2021	A0	9.39% (100 mg/L)	1.078	99.85	23.98
29.09.2021	E0	9.39% (100 mg/L)	1.074	99.48	23.89
29.09.2021	A1	9.39% (100 mg/L)	1.014	93.92	22.56
30.09.2021	E1	9.39% (100 mg/L)	1.016	94.10	22.60
28.09.2021	A0	20.7% (100 mg/L)	2.391	100.46	24.13
29.09.2021	E0 (Rep. 2)	20.7% (100 mg/L)	2.427	101.97	24.49
29.09.2021	A1	20.7% (100 mg/L)	2.230	93.69	22.50
30.09.2021	E1	20.7% (100 mg/L)	2.241	94.16	22.62
28.09.2021	A0	45.5% (100 mg/L)	5.394	103.10	24.76
29.09.2021	E0	45.5% (100 mg/L)	5.326	101.80	24.45
29.09.2021	A1	45.5% (100 mg/L)	4.916	93.97	22.57
30.09.2021	E1	45.5% (100 mg/L)	5.016	95.88	23.03
28.09.2021	A0	100% (100 mg/L)	11.80	102.63	24.65
29.09.2021	E0	100% (100 mg/L)	11.82	102.80	24.69
29.09.2021	A1	100% (100 mg/L)	11.15	96.97	23.29
30.09.2021	E1	100% (100 mg/L)	10.94	95.15	22.85

1)Mo recovery corresponding to Mo solubility (11.498 mg Mo/L per 100 mg/L test item).
2)Mo recovery corresponding to Mo content (47.87%, stoichiometric) of Mo10V3TeNbO42.

Data for the evaluation of the linearity of the molybdenum calibration solutions.

Concentration	Intensity	Intensity	Intensity	Intensity	Regression residuals
	mean value	value 1	value 2	value 3
[mg/L]	[counts/s]	[counts/s]	[counts/s]	[counts/s]	[%]
0.00	1.826	1.407	1.626	2.445	-
0.009	7.454	6.857	7.476	8.028	33.756
0.03	22.06	20.35	22.79	23.03	10.224
0.05	34.02	33.70	34.21	34.16	0.595
0.1	69.87	70.31	68.90	70.40	1.914
0.3	203.3	201.5	205.4	202.8	-2.003
0.5	338.7	339.6	339.6	336.9	-2.198
1.0	697.5	698.2	697.7	696.7	0.573
3.0	2080	2077	2084	2080	-0.103
5.0	3473	3476	3477	3465	0.042

 

1st Level (0.03 mg/L, LOQ level):
Data for the evaluation of the recovery and repeatability of Mo concentration 1st level
using spiked samples (0.03 mg/L).

Validation	Nominal Mo	Measured Mo	Recovery	Intensity mean	Intensity value 1	Intensity value 2	Intensity value 3
sample no.	concentration	concentration
	[mg/L]	[mg/L]	[%]	[counts/s]	[counts/s]	[counts/s]	[counts/s]
1	0.03	0.03312	110.40	22.10	20.52	22.03	23.76
2	0.03	0.03219	107.30	21.45	22.20	21.05	21.09
3	0.03	0.03331	111.03	22.23	21.50	22.84	22.35
4	0.03	0.03217	107.23	21.44	21.15	20.93	22.25
5	0.03	0.03281	109.37	21.88	21.80	21.01	22.82
Mean			109.07
SD			1.75
%RSD			1.60

The results for the first spiking level with a nominal concentration of 0.03 mg Mo/L led to a mean recovery rate of 109% and an RSD of 2%. This fulfils the specification (mean recovery 70% to 120% and RSD ≤ 20%) and therefore is acceptable.

 

2nd Level (0.30 mg/L, 10 x LOQ level):
Data for the evaluation of the recovery and repeatability of Mo concentration 2nd level using spiked samples (0.30 mg/L).

Validation	Nominal Mo	Measured Mo	Recovery	Intensity mean	Intensity value 1	Intensity value 2	Intensity value 3
sample no.	concentration	concentration
	[mg/L]	[mg/L]	[%]	[counts/s]	[counts/s]	[counts/s]	[counts/s]
6	0.30	0.29421	98.07	203.4	203.3	203.6	203.4
7	0.30	0.29666	98.89	205.1	203.1	204.5	207.7
8	0.30	0.29882	99.61	206.6	206.6	205.6	207.5
9	0.30	0.29507	98.36	204.0	204.7	204.1	203.4
10	0.30	0.29608	98.69	204.7	204.5	205.1	204.6
Mean			98.72
SD			0.59
%RSD			0.60

The results for the second spiking level with a nominal concentration of 0.30 mg Mo/L led to a mean recovery rate of 99% and an RSD of 1% (i.e. 0.6%). This fulfils the specification (mean recovery 70% to 120% and RSD ≤ 20%) and therefore is acceptable.

All analytical samples were analysed within 24 h. Therefore, the stability of the analyte was sufficiently proven, with the acceptable recoveries of the fortified samples (70% to 120%).

Results and Discussion
The individual results for molybdenum concentration of each provided sample solution and the mean results for the two-fold determination are given in the tables below.

No. of analysis	Date	Sample code/description	Intensity	Mo
				concentration*
	[yyyy-mm-dd]		[counts/s]	[mg/L]
1	30.09.2021	Test medium	1.534	< 0.01
2	30.09.2021	Test medium	1.415	< 0.01
Mean	30.09.2021	Test medium	1.475	< 0.01

*Results of Mo concentration of the provided blank sample solution were calculated considering the applied sample volume of 9 mL acidified and diluted to 10 mL.

The mean intensity of provided blank sample solution was 1.475 counts/s. This led to a molybdenum concentration below the lowest calibration point (< 0.01 mg/L).

 

Results of molybdenum concentration in provided samples solutions (with dissolved test item Mo10V3TeNbO42 and control samples), part 1.

No. of analysis	Date	Sample	Sample	Intensity	Mean measured Mo concentration*	Recovery^1)	Recovery^2)
	[yyyy-mm-dd]	code	description (100 mg/L)	[counts/s]	[mg/L]	[%]	[%]
1	2021-09-28	A0	Control	1.894	< 0.01	-	-
2	2021-09-28	A0	Control	1.239
1	2021-09-29	E0	Control	0.4854	< 0.01	-	-
2	2021-09-29	E0	Control	1.839
1	2021-09-29	A1	Control	0.6499	< 0.01	-	-
2	2021-09-29	A1	Control	1.796
1	2021-09-30	E1	Control	1.368	< 0.01	-	-
2	2021-09-30	E1	Control	1.134
1	2021-09-28	A0	4.27%	310.0	0.4955	100.92	24.24
2	2021-09-28	A0	4.27%	307.6
1	2021-09-29	E0	4.27%	309.2	0.4944	100.70	24.19
2	2021-09-29	E0	4.27%	306.9
1	2021-09-29	A1	4.27%	289.6	0.4629	94.28	22.65
2	2021-09-29	A1	4.27%	287.2
1	2021-09-30	E1	4.27%	291.3	0.4676	95.24	22.88
2	2021-09-30	E1	4.27%	291.4
1	2021-09-28	A0	9.39%	673.6	1.078	99.85	23.98
2	2021-09-28	A0	9.39%	671.7
1	2021-09-29	E0	9.39%	677.3	1.074	99.48	23.89
2	2021-09-29	E0	9.39%	663.4
1	2021-09-29	A1	9.39%	636.0	1.014	93.92	22.56
2	2021-09-29	A1	9.39%	629.8
1	2021-09-30	E1	9.39%	637.8	1.016	94.10	22.60
2	2021-09-30	E1	9.39%	630.0
1	2021-09-28	A0	20.7%	1494	2.391	100.46	24.13
2	2021-09-28	A0	20.7%	1494
1	2021-09-29	E0**	20.7%	1513	2.427	101.97	24.49
2	2021-09-29	E0**	20.7%	1519
1	2021-09-29	A1	20.7%	1396	2.230	93.69	22.50
2	2021-09-29	A1	20.7%	1390
1	2021-09-30	E1	20.7%	1401	2.241	94.16	22.62
2	2021-09-30	E1	20.7%	1398

*Results of Mo concentration were calculated considering the applied sample volume of 9 mL acidified and diluted to 10 mL.
**Rep. 2 used.
1)Mo recovery corresponding to Mo solubility (11.498 mg Mo/L per 100 mg/L test item).
2)Mo recovery corresponding to Mo content (47.87%, stoichiometric) of Mo10V3TeNbO42.

 

Results of molybdenum concentration in provided samples solutions (with dissolved test item Mo10V3TeNbO42 and control samples), part 2.

No. of analysis	Date	Sample	Sample	Intensity	Mean measured Mo concentration*	Recovery^1)	Recovery^2)
	[yyyy-mm-dd]	code	description (100 mg/L)	[counts/s]	[mg/L]	[%]	[%]
1	2021-09-28	A0	45.5%	674.7	5.394	103.10	24.76
2	2021-09-28	A0	45.5%	672.0
1	2021-09-29	E0	45.5%	663.6	5.326	101.80	24.45
2	2021-09-29	E0	45.5%	665.9
1	2021-09-29	A1	45.5%	617.2	4.916	93.97	22.57
2	2021-09-29	A1	45.5%	610.0
1	2021-09-30	E1	45.5%	629.9	5.016	95.88	23. Mrz
2	2021-09-30	E1	45.5%	622.2
1	2021-09-28	A0	100%	735.0	11.80	102.63	24.65
2	2021-09-28	A0	100%	738.0
1	2021-09-29	E0	100%	738.6	11.82	102.80	24.69
2	2021-09-29	E0	100%	737.2
1	2021-09-29	A1	100%	697.1	11.15	96.97	23.29
2	2021-09-29	A1	100%	694.2
1	2021-09-30	E1	100%	681.3	10.94	95.15	22.85
2	2021-09-30	E1	100%	684.2

*Results of Mo concentration were calculated considering the applied sample volume of 9 mL acidified and diluted to 10 mL as well as dilution factors 5 for samples “45.5%” and 10 for samples “100%”.
1)Mo recovery corresponding to Mo solubility (11.498 mg Mo/L per 100 mg/L test item).
2)Mo recovery corresponding to Mo content (47.87%, stoichiometric) of Mo10V3TeNbO42.

The results for the molybdenum concentrations of the provided sample solutions are reasonable regarding the sample description. The recoveries regarding the Mo solubility (11.498 mg Mo/L per 100 mg/L test item) were 94% to 103% and regarding the stoichiometric Mo content (47.87%) 23% to 25%.

 

 

 

 

 

 

Validity criteria fulfilled:

yes

Conclusions:

Based on the nominal loading rate, respectively the calculated nominal loading rate (saturated solution with a loading of 100 mg test item/L) of the test item, the 48 hours-EL50 for Daphnia magna was 47.0 mg/L (Confidence limits: 22.1 – 97.2mg/L) for the test item Mo10V3TeNbO42.

Executive summary:

In the acute immobilization test with Daphnia magna (STRAUS), the effects of the test item Mo10V3TeNbO42 were determined at the test facility and the test site according to OECD 202 (2004) from 2021-09-24 to 2021-10-07 with the definitive exposure phase from 2021-09-28 to 2020-09-30.
The study was conducted under semi-static conditions over a period of 48 hours with five concentrations of the test item (nominal: 4.27 to 100 mg/L) prepared from a saturated solution of 100 mg test item/L in a geometric series with a separation factor of 2.2. The nominal loading rates and the control were colorless and clear throughout the exposure.
Twenty daphnids (divided into 4 replicates with 5 daphnids each) were exposed to each concentration level and the control.
The test concentrations and the control were analytically verified via determination of the molybdenum concentration by the test site. Analysis was carried out in the fresh media at the start of the exposure and at the renewal of the test solutions (0 and 24 hours) as well as in the 24 hours old media at the renewal and at the end of the test (24 and 48 hours) in the nominal loading rates and in the control.
The validity criteria of the test guidelines were fulfilled.

EL10-, EL50-, EL100-Values
(based on the nominal loading rates of the test item)

Effect values	Test	Nominal loading rates of the test item [mg/L]
	duration
	[hours]
EL10	24	100 (45.5 – > 100)
(with confidence limits)	48	43.3* (21.0 to 95.5)
EL50	24	> 100
(with confidence limits)	48	47.0* (22.1 – 97.2)
EL100	24	> 100
	48	> 100

*calculated nominal loading from a saturated solution

Description of key information

Based on the nominal loading rate, respectively the calculated nominal loading rate (saturated solution with a loading of 100 mg test item/L) of the test item, the 48 hours-EL50 for Daphnia magna was 47.0 mg/L (Confidence limits: 22.1 – 97.2mg/L) for the test item Mo10V3TeNbO42.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

47 mg/L