Sodium [4-[[dihydroxy[(2-hydroxy-3,5-dinitrophenyl)azo]phenyl]azo]benzenesulphonato(3-)]cuprate(1-)

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Oct 14, 2016 - Dec 20, 2016

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)

Version / remarks:

OECD 201:2011

Deviations:

no

GLP compliance:

yes

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

- Source (laboratory, culture collection): National Chiayi University Freshwater Bioresource Center
- Acclimation period: 2-4 days

Water media type:

freshwater

Total exposure duration:

72 h

Test temperature:

21-24°C

Nominal and measured concentrations:

1.29, 1.68, 2.18, 2.83 and 3.68 mg/L

Details on test conditions:

- Test vessel: 125 mL glass flask
- Test volume: 60 mL
- Type of cover: sealed with silicone plugs
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3
- Light intensity and quality: 4440-8880 lux

Key result

Duration:

72 h

Dose descriptor:

EC50

Remarks:

ErC50

Effect conc.:

3.1 mg/L

Duration:

72 h

Dose descriptor:

EC50

Remarks:

EyC50

Effect conc.:

1.65 mg/L

Table 1: The algal biomass for the definitive test

Group (mg/L)		Mean of algal biomass (×10^4cells/mL) ± standard deviation
		Day 0	Day 1	Day 2	Day 3
Control group	0.00	1.00 ± 0.00	2.71 ± 0.46	4.35 ± 0.12	23.38 ± 1.94
Test group	3.68	1.00 ± 0.00	1.11 ± 0.02	1.53 ± 0.09	3.95 ± 0.13
	2.83	1.00 ± 0.00	1.08 ± 0.03	2.07 ± 0.12	4.20 ± 0.83
	2.18	1.00 ± 0.00	1.11 ± 0.01	3.10 ± 0.24	10.96 ± 1.09
	1.68	1.00 ± 0.00	1.18 ± 0.06	3.62 ± 0.09	11.55 ± 2.01
	1.29	1.00 ± 0.00	1.60 ± 0.19	4.28 ± 0.34	14.87 ± 4.29

Table 2. Theaverage specific growth ratefor the definitive test

Group (mg/L)		Mean of average specific growth rate (d^-1) ± standard deviation (Coefficient of variation [%])
		Day 0-1	Day 1-2	Day 2-3	Day 0-3
Control group	0.00	0.99 ± 0.17 (16.97)	0.48 ± 0.15 (31.58)	1.68 ± 0.11 (6.47)	1.05 ± 0.03 (2.62)
Test group	3.68	0.11 ± 0.02 (17.51)	0.31 ± 0.05 (16.10)	0.95 ± 0.03 (3.06)	0.46 ± 0.01* (2.40)
	2.83	0.08 ± 0.02 (29.03)	0.65 ± 0.04 (6.38)	0.70 ± 0.13 (19.01)	0.47 ± 0.06* (13.24)
	2.18	0.11 ± 0.01 (9.69)	1.02 ± 0.07 (7.01)	1.26 ± 0.02 (1.80)	0.80 ± 0.03* (4.06)
	1.68	0.17 ± 0.06 (32.96)	1.12 ± 0.06 (4.98)	1.15 ± 0.16 (13.72)	0.81 ± 0.06* (7.45)
	1.29	0.47 ± 0.13 (26.88)	0.98 ± 0.18 (18.61)	1.22 ± 0.30 (24.49)	0.89 ± 0.10* (10.83)

Table 3: The percent inhibition in average specific growth rate and percent inhibition of yield for the definitive test.

Group (mg/L)	Logarithm of concentration (mg/L)	Percent inhibition in average specific growth rate (%)	Percent inhibition of yield (%)
3.68	0.57	55.36	86.24
		56.47	86.87
		57.45	87.40
2.83	0.45	47.96	81.46
		57.87	87.62
		58.72	88.07
2.18	0.34	25.62	57.96
		26.08	58.63
		20.53	49.87
1.68	0.23	29.06	62.74
		20.98	50.63
		17.91	45.18
1.29	0.11	5.81	17.66
		24.16	55.77
		15.56	40.63

Table 4: ECx and 95% confidence interval for the definitive test.

Parameter	ErC10^a	ErC20	ErC50	EyC10^b	EyC20	EyC50
ECX(mg/L)	1.24	1.56	3.10	0.74	0.91	1.65
95% confidence interval-lower	0.66	1.22	2.75	0.14	0.37	1.36
95% confidence interval-upper	1.43	1.79	3.55	0.86	1.05	1.92

^a E_rC_xwas calculated by percent inhibition in average specific growth rate.

^b E_yC_xwas calculated by percent inhibition of yield.

Table 5: The pH value for the definitive test.

Group (mg/L)		Mean of pH value ± standard deviation
		Day 0	Day 3
Control group	0.00	7.50 ± 0.26	7.66 ± 0.15
Test group	3.68	7.59 ± 0.02	7.75 ± 0.01
	2.83	7.59 ± 0.03	7.74 ± 0.03
	2.18	7.65 ± 0.02	7.68 ± 0.05
	1.68	7.60 ± 0.04	7.65 ± 0.02
	1.29	7.51 ± 0.13	7.59 ± 0.05

Validity criteria fulfilled:

yes

Conclusions:

According to OECD 201 test method, the ErC50 and the EyC50 of Everlan SL65 was 3.10 mg/L and 1.65 mg/L respectively.

Executive summary:

This test using the procedures outlined in the SuperLab Study Plan for M62-151100107001EN which is based on the SOP for the OECD 201 (SOPE-504) and OECD 201 (OECD, 2011). The results of this OECD 201 test for Everlan SL65 show that test validity criteria was met. In the alga growth inhibition test (definitive test), the test article concentrations applied were 1.29, 1.68, 2.18, 2.83 and 3.68 mg/L. Under the test conditions, the E_rC₅₀ and the E_yC₅₀ of Everlan SL65 was 3.10 mg/L and 1.65 mg/L respectively.

Description of key information

Respectively, the E_rC₅₀and the E_yC₅₀of Everlan SL65 was 3.10 mg/L and 1.65 mg/L for Pseudokirchneriella subcapitata (OECD TG201).

Key value for chemical safety assessment

EC50 for freshwater algae:

3.1 mg/L

Additional information

The biomass in the control group have increased exponentially by a factor of at least 16 within the 72-hour test period. The specific growth rate in the control group was more than 0.92 d^-1. The mean coefficient of variation for specific growth rates (Day 0-1, Day 1-2, Day 2-3, and Day 0-3) in the control group were not exceed 35%. The coefficient of variation of average specific growth rates during the whole test period in replicate control groups were not exceed 7%. The variation in the pH values in the beginning and end of the tests was less than 1.5 units. Under the test conditions, the E_rC₅₀ and the E_yC₅₀ of Everlan SL65 was 3.10 mg/L and 1.65 mg/L respectively.