Cadmium selenide

Additional information on environmental fate and behaviour

Administrative data

Endpoint:

additional information on environmental fate and behaviour

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29 October 2018 to 04 December 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other:

Version / remarks:

OECD 29: Transformation/Dissolution of Metals and Metal Compounds in Aqueous Media, adopted
on 23 July 2001.

Deviations:

not specified

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Cadmium selenide

EC Number:

215-148-3

EC Name:

Cadmium selenide

Cas Number:

1306-24-7

Molecular formula:

CdSe

IUPAC Name:

cadmium selenide

Test material form:

solid

Results and discussion

Any other information on results incl. tables

Screening test

The results showed the lowest solubility of test item in the buffering solution with pH 8.5. As there were no observable deviation between the solutions with pH 6 and pH 7 it was decided to use the buff

ering solution with pH 6 for the full transformation/ dissolution test. The diluted cadmium contents of the test vessels with pH 6 varied between 88 μg / L and 110 μg / L.

All oxygen levels were within the recommended range of the OECD Test Guideline 29.

Main test

The results of the transformation/ dissolution of "Cadmium selenide" in dissolution medium with a pH of approximately 6 with different loading rates at 22 ± 2°C are listed in sections 6.2.2 and 6.2.3.

The temperatures during the whole experiment were between 20.8 and 23.5 °C.

The pH values of the solutions were between 6.1 and 6.3 at all loading rates and therefore remained constant during the whole experiment.

The following results were obtained at the different loading rates:

1 mg test item / L: 23 μg Cd / L after 7 days (short term test)

Solubility equilibrium of 43.7 ± 4.6 μg Cd / L has been reached between 336 h (14 days) and 672 h (28 days) because three subsequent total dissolved metal concentration data points vary no more

than 15 % according to the OECD Test Guideline 29. 10 mg test item / L: 171 μg Cd / L after 7 days (short term test)

No solubility equilibrium have been reached during the test period of seven days.

100 mg test item / L: 551 μg Cd / L after 7 days (short term test)

No solubility equilibrium have been reached during the test period of seven days.

All oxygen levels were within the recommended range of the OECD Test Guideline 29.

The numerical data in the tables have been rounded for presentation, a manual recalculation therefore may yield slightly different results to those given in the tables.       

Screening test

Buffering solution with pH 6

Equilibration time	Concentration of dissolved µg Cd / L				pH
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Vessel 1	110	106	109	108	6.0
Vessel 2	105	101	103	103	6.0
Vessel 3	91	88	91	90	5.9
Overall mean				100	6.0
Overall standard deviation				8	0.0

Buffering solution with pH 7

Equilibration time	Concentration of dissolved µg Cd / L				pH
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Vessel 1	81	81	81	81	7.0
Vessel 2	111	111	112	111	7.0
Vessel 3	105	105	105	105	7.1
Overall mean				99	7.0
Overall standard deviation				14	0.1

Buffering solution with pH 8.5

Equilibration time	Concentration of dissolved µg Cd / L				pH
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Vessel 1	56	56	58	57	8.4
Vessel 2	53	53	54	53	8.4
Vessel 3	74	74	74	74	8.5
Overall mean				61	8.4
Overall standard deviation				10	0.1

 

Short term dissolution tests

Transformation / dissolution - initial loading rate of 10 mg test item / L

Equilibration time	Concentration of dissolved µg Cd / L
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Start = 0 h	< 3.1	< 3.1	< 3.1	< 3.1
2 h	3.9	5.5	3.7	4.4
6 h	11	19	12	14
24 h (=1 d)	18	33	21	24
72 h (=3 d)	72	140	92	102
168 h (=7 d)	140	185	188	171

Equilibration time	Concentration in µg test item / L
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Start = 0 h	< 5.2	< 5.2	< 5.2	< 5.2
2 h	6.6	9.4	6.3	7.4
6 h	19	32	21	24
24 h (=1 d)	31	56	36	41
72 h (=3 d)	123	239	157	173
168 h (=7 d)	238	315	320	291

 

Equilibration time	pH
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Start = 0 h	6.3	6.3	6.3	6.3
2 h	6.1	6.2	6.2	6.2
6 h	6.2	6.2	6.2	6.2
24 h (=1 d)	6.2	6.2	6.1	6.2
72 h (=3 d)	6.3	6.3	6.3	6.3
168 h (=7 d)	6.3	6.3	6.2	6.2

Transformation / dissolution - initial loading rate of 100 mg test item / L

Equilibration time	Concentration of dissolved µg Cd / L
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Start = 0 h	< 3.1	< 3.1	< 3.1	< 3.1
2 h	29	30	23	28
6 h	80	90	72	80
24 h (=1 d)	117	136	111	121
72 h (=3 d)	323	406	332	354
168 h (=7 d)	529	587	537	551

Equilibration time	Concentration in µg test item / L
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Start = 0 h	< 5.2	< 5.2	< 5.2	< 5.2
2 h	50	52	40	47
6 h	137	152	122	137
24 h (=1 d)	199	232	189	207
72 h (=3 d)	550	691	565	602
168 h (=7 d)	900	999	913	937

Equilibration time	pH
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Start = 0 h	6.3	6.3	6.3	6.3
2 h	6.1	6.1	6.1	6.1
6 h	6.1	6.2	6.1	6.1
24 h (=1 d)	6.2	6.2	6.1	6.2
72 h (=3 d)	6.3	6.2	6.2	6.2
168 h (=7 d)	6.2	6.3	6.2	6.3

Long term dissolution test

Transformation / dissolution - initial loading rate of 1 mg test item / L

Equilibration time	Concentration of dissolved µg Cd / L
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Start = 0 h	< 3.1	< 3.1	< 3.1	< 3.1
2 h	< 3.1	< 3.1	< 3.1	< 3.1
6 h	< 3.1	< 3.1	< 3.1	< 3.1
24 h (=1 d)	3.5	3.8	3.1	3.5
72 h (=3 d)	14	14	11	13
168 h (=7 d)	26	24	19	23
336 h (=14 d)	41	42	33	39
504 h (=21 d)	44	46	44	44
672 h (=28 d)	44	52	48	48

Equilibration time	Concentration in µg test item / L
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Start = 0 h	< 5.2	< 5.2	< 5.2	< 5.2
2 h	< 5.2	< 5.2	< 5.2	< 5.2
6 h	< 5.2	< 5.2	< 5.2	< 5.2
24 h (=1 d)	5.9	6.5	5.3	5.9
72 h (=3 d)	24	23	18	22
168 h (=7 d)	44	41	33	39
336 h (=14 d)	71	71	57	66
504 h (=21 d)	75	78	75	76
672 h (=28 d)	75	88	82	82

 

Equilibration time	pH
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Start = 0 h	6.2	6.3	6.3	6.3
2 h	6.1	6.2	6.1	6.1
6 h	6.2	6.2	6.2	6.2
24 h (=1 d)	6.2	6.1	6.1	6.1
72 h (=3 d)	6.2	6.3	6.3	6.2
168 h (=7 d)	6.1	6.2	6.2	6.2
336 h (=14 d)	6.2	6.2	6.2	6.2
504 h (=21 d)	6.3	6.3	6.2	6.3
672 h (=28 d)	6.3	6.2	6.3	6.3

Blank solutions for short and long term dissolution test

Equilibration time	Concentration of dissolved µg Cd / L
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Start = 0 h	< 3.1	< 3.1	< 3.1	< 3.1
2 h	< 3.1	< 3.1	< 3.1	< 3.1
6 h	< 3.1	< 3.1	< 3.1	< 3.1
24 h (=1 d)	< 3.1	< 3.1	< 3.1	< 3.1
72 h (=3 d)	< 3.1	< 3.1	< 3.1	< 3.1
168 h (=7 d)	< 3.1	< 3.1	< 3.1	< 3.1
336 h (=14 d)	< 3.1	< 3.1	< 3.1	< 3.1
504 h (=21 d)	< 3.1	< 3.1	< 3.1	< 3.1
672 h (=28 d)	< 3.1	< 3.1	< 3.1	< 3.1

Equilibration time	Concentration in µg test item / L
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Start = 0 h	< 5.2	< 5.2	< 5.2	< 5.2
2 h	< 5.2	< 5.2	< 5.2	< 5.2
6 h	< 5.2	< 5.2	< 5.2	< 5.2
24 h (=1 d)	< 5.2	< 5.2	< 5.2	< 5.2
72 h (=3 d)	< 5.2	< 5.2	< 5.2	< 5.2
168 h (=7 d)	< 5.2	< 5.2	< 5.2	< 5.2
336 h (=14 d)	< 5.2	< 5.2	< 5.2	< 5.2
504 h (=21 d)	< 5.2	< 5.2	< 5.2	< 5.2
672 h (=28 d)	< 5.2	< 5.2	< 5.2	< 5.2

Equilibration time	pH
Start = 0 h	6.3
2 h	6.2
6 h	6.2
24 h (=1 d)	6.2
72 h (=3 d)	6.2
168 h (=7 d)	6.2
336 h (=14 d)	6.2
504 h (=21 d)	6.2
672 h (=28 d)	6.3

Validation Results

Linearity

The calibration curve was linear from the quantification limit up to the highest concentration of 100 µg Cd / L. The coefficient of determination (R²) was 0.99996.

The following functions were received:

y [cps] = 94.01893 [cps/(µg / L)] * x [µg / L] + 79.45502 [cps]

where
x = nominal concentration of cadmium in µg / L
y = signal in counts per second (cps)

with the following ranges respectively confidence intervals for slope and intercept of the linear function:

Slope: 93.83990 – 94.19796 = 94.01893±0.17903
Intercept: 70.15852 – 88.75152 = 79.45502±9.29650

Detection limit

0.17 µg Cd / L in the diluted samples, which corresponds to 1.4 µg test item / L calculated with a dilution factor of 5 (rounded to two significant digits).

Quantification limit

0.61 µg Cd / L in the diluted samples, which corresponds to 5.2 µg test item / L calculated with a dilution factor of 5 (rounded to two significant digits).

Residual standard deviation

The residual standard deviation was 20 counts per second (cps) in the diluted samples.

Method standard deviation

The method standard deviation was 0.22 µg Cd / L in the diluted samples.

Relative method standard deviation

The relative method standard deviation was 0.57 %.

Accuracy

Sample	Measured concentration without addition (µg Cd / L)	Added concentration calculated (µg Cd / L)	Measured concentration with addition (µg Cd / L)	Added concentration measured (µg Cd / L)	Recovery (%)
Measurement 1	14.21	15	29.45	15.24	102
Measurement 2	14.45	15	29.47	15.02	100
Measurement 3	14.63	15	29.54	14.91	99
				Mean	100

The mean recovery of the standard addition experiment was 100 %.

 

Reproducibility

	Concentration of dissolved µg Cd / L
	1^streplicate	2^ndreplicate	3^rdreplicate	Within- vessel
				Mean	Standard deviation	Relative Standard deviation [%]
Vessel 1	110	106	109	108	2	2
Vessel 2	105	101	103	103	2	2
Vessel 3	91	88	91	90	2	2
Vessel 4	117	117	117	117	0	0
Vessel 5	137	135	137	136	1	1
Vessel 6	111	111	110	111	1	0
Mean between-vessel				111	---	---
Standard deviation between-vessel				15	---	---
Relative standard deviation between-vessel [%]				14	---	---

The calculated relative standard deviations (RSD) of the results were lower than the recommended values (< 20 % between-vessel and < 10% within- vessel) and therefore prove the reproducibility of the analysis.

Specificity / Selectivity

The specificity of the element cadmium was proved by using two different wavelengths which are characteristic and specific for cadmium. The specificity was calculated from the measurements of the spiked samples from the accuracy experiments.

Sample	Measured concentration (µg Cd / L)
	214.400 nm	228.802 nm
Measurement 1	15.24	15.22
Measurement 2	15.02	14.92
Measurement 3	14.91	15.11
Mean	15.06	15.08

The deviation between the two wavelengths was lower than 1 % relative and prove the specificity of the used wavelengths.  

Applicant's summary and conclusion

Conclusions:

At a loading of 1 mg test item / L, the dissolved mean concentration was 23 μg Cd / L (39 μg test it em / L) after the 7 days transformation / dissolution test and the equilibrium concentration observed within the test period of 28 days was 43.7 μg Cd / L (74 μg test item / L).

At a loading of 10 mg test item / L, the dissolved mean concentration was 171 μg Cd / L (291 μg test item / L) after the 7 days transformation / dissolution test. Within the test period of 7 days no equilibrium was observed.

At a loading of 100 mg test item / L, the dissolved mean concentration was 551 μg Cd / L (937 μg test item / L) after the 7 days transformation / dissolution test. Within the test period of 7 days no equilibrium was observed.

Executive summary:

The objective of the study was to determine the transformation / dissolution of the test substance"Cadmiumselenide". For the complete test substance no single analytical method is available. The transformation / dissolution was therefore estimated by analysis of the element cadmium.

The screening test showed that at pH of 6 maximises the dissolution of cadmium selenide. Therefore the full transformation/ dissolution tests were performed with a dissolution media with this pH value.

Main experiments

Short term transformation / dissolution at 22±2 °C per loading rate: 1 mg test item / L:                23 µg Cd / L after 7 days                                              pH range: 6.1 to 6.3 10 mg test item / L:              171 µg Cd / L after 7 days                                              pH range: 6.1 to 6.3 100 mg test item / L:            551 µg Cd / L after 7 days                                              pH range: 6.1 to 6.3   Long term transformation / dissolution at 22±2 °C per loading rate: 1 mg test item / L:                Solubility equilibrium of 43.7 ± 4.6 µg                                             Cd / L has been reached between                                             336 h (14 days) and 672 h (28 days)                                              pH range: 6.1 to 6.3

In each of the blank vessels without test item the content of diluted test item was less than the limit of quantification (< 5.2 µg / L) of the analytical method.

The observed levels and variations in temperature, pH and oxygen concentrations were in compliance with the test guideline OECD 29.

The transformation curves can be found in Appendix 3 as plots of time and measured cadmium concentrations.

Conclusion

At a loading of 1 mg test item / L, the dissolved mean concentration was 23 µg Cd / L (39 µg test item / L) after the 7 days transformation / dissolution test and the equilibrium concentration observed within the test period of 28 days was 43.7 µg Cd / L (74 µg test item / L).

 

At a loading of 10 mg test item / L, the dissolved mean concentration was 171 µg Cd / L (291 µg test item / L) after the 7 days transformation / dissolution test. Within the test period of 7 days no equilibrium was observed.

 

At a loading of 100 mg test item / L, the dissolved mean concentration was 551 µg Cd / L (937 µg test item / L) after the 7 days transformation / dissolution test. Within the test period of 7 days no equilibrium was observed.