CJ309

Toxicity to aquatic plants other than algae

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic plants other than algae

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From November 26, 2015 to January 05, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 221 (Lemna sp. Growth Inhibition Test)

GLP compliance:

yes

Test organisms (species):

Lemna minor

Details on test organisms:

- Source (laboratory, culture collection): Canadian Phycological Culture Centre, Waterloo, ON, Canada
- Culturing media and conditions (same as test): Sterile synthetic growth media, Swedish Standard (SIS)

Test type:

static

Water media type:

freshwater

Total exposure duration:

7 d

Test temperature:

24 ± 2°C

pH:

6.6-7.6

Nominal and measured concentrations:

Nominal concentrations of the Test Item were 6.25, 12.5, 25, 50 and 100 mg/L

Details on test conditions:

- Test vessel: 250 mL Erlenmeyer flask
- Test volume: ~125 mL
- Type of cover: sealed with foam plugs
- No. of fronds per replicate: 9
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 8
- Standard medium used: yes
- Photoperiod: Continuous 24-h light
- Light intensity and quality: 90-126μmol/m2/s
- Determination of frond number: manual counting
- Determination of biomass: dry weight

Reference substance (positive control):

yes

Remarks:

Nickel sulphate hexahydrate (CAS No. 10101-97-0)

Duration:

7 d

Dose descriptor:

EC50

Remarks:

for yield

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

frond number

Duration:

7 d

Dose descriptor:

EC50

Remarks:

for yield

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

7 d

Dose descriptor:

EC50

Remarks:

for Specific Growth Rate (SGR)

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

frond number

Duration:

7 d

Dose descriptor:

EC50

Remarks:

for Specific Growth Rate (SGR)

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Results with reference substance (positive control):

7-Day EC25: 5.40 mg Ni/L

The control doubling time was calculated to be 2.05days. The initial pH measurements did not differ from the final measurements by more than 1.5 units and the test was maintain within 24 ± 2°C. At the end of test, the plants in the negative control up to the 100 mg/L test concentration appeared light green, healthy, with some transparent fronds.

Table 1. Mean Yield and Specific Growth Rate (SGR) Based on Frond Number

Nominal Concentration (mg/L)	Frond Number (Day 0-7)			Frond Number (Day 0-7)
	Mean Yield	SD	% CV	Mean SGR	SD	% CV
Negative Control	87.9	13.8	15.7	0.34	0.02	5.9
6.25	78.3	15.3	19.6	0.32	0.03	8.5
12.5	71.3	8.3	11.6	0.31	0.01	4.6
25	73.8	10.3	14.0	0.32	0.02	5.6
50	65.5	2.1	3.2	0.30	0.00	1.3
100	60.8	3.3	5.4	0.29	0.01	2.4

Table 2. Mean Yield and Specific Growth Rate (SGR) Based on Dry Weight

Nominal Concentration (mg/L)	Dry Weight (Day 0-7)			Dry Weight (Day 0-7)
	Mean Yield (mg)	SD (mg)	% CV	Mean SGR	SD	% CV
Negative Control	8.20	0.95	11.6	0.40	0.02	3.8
6.25	7.33	1.51	20.6	0.38	0.03	7.7
12.5	6.30	1.29	20.4	0.37	0.03	6.9
25	6.29	1.09	17.3	0.37	0.02	6.3
50	5.78	0.38	6.6	0.36	0.01	2.5
100	5.27	0.23	4.4	0.34	0.01	1.7

Table 3. Mean Percent Inhibition in Yield Based on Frond Number and Dry Weight

Nominal Concentration (mg/L)	Mean % Inhibition (Frond Number)	Mean % Inhibition (Dry Weight)
Negative Control	N/A	N/A
6.25	11.0	10.6
12.5	18.9	23.2
25	16.1	23.3
50	25.5	29.5
100	30.9	35.7

Table 4. Mean Percent Inhibition in Specific Growth Rate (SGR) Based on Frond Number and Dry Weight

Nominal Concentration (mg/L)	Mean % Inhibition (Frond Number SGR)	Mean % Inhibition (Dry Weight SGR)
Negative Control	N/A	N/A
6.25	4.6	4.1
12.5	7.7	9.0
25	6.5	9.0
50	10.7	11.4
100	13.5	14.4

Table 5. Test Endpoint Summary for CJ309-Yield and SGR

		Nominal Concentrations (mg/L)
		EC50 (95% CL) (mg/L)	NOEC (mg/L)	LOEC (mg/L)
Yield	Frond Number	>100 (N/A)	25	50
	Dry Weight	>100 (N/A)	6.25	12.5
SGR	Frond Number	>100 (N/A)	25	50
	Dry Weight	>100 (N/A)	6.25	12.5

Note: N/A-Not Applicable

Validity criteria fulfilled:

yes

Conclusions:

According to OECD 221 test method, the 7-days EC50 of CJ309 was >100mg/L.

Executive summary:

This test using the procedures outlined in the Maxxam Study Plan for TOX1515 which is based on the SOP for the OECD 221 (BBY2 SOP-00067) and OECD 221 (OECD, 2006).The results of this OECD 221 test for CJ309 show that test validity criteria was met.

Based on the nominal concentrations of CJ309:

1.     The 7-Day EC50 for yield based on frond number was >100 mg/L. The NOEC and LOEC was 25 mg/L and 50 mg/L, respectively.

2.     The 7-Day EC50 for yield based on dry weight was >100 mg/L. The NOEC and LOEC was 6.25 mg/L and 12.5 mg/L, respectively.

3.     The 7-Day EC50 for Specific Growth Rate based on frond number was >100 mg/L. The NOEC and LOEC was 25 mg/L and >50 mg/L, respectively.

4.     The 7-Day EC50 for Specific Growth Rate based on dry weight was >100 mg/L. The NOEC and LOEC was 6.25 mg/L and 12.5 mg/L, respectively.

Description of key information

The 7-days EC50 of CJ309 was >100mg/L for Lemna minor (OECD TG221).

Key value for chemical safety assessment

EC50 for freshwater plants:

100 mg/L

Additional information

The test was considered valid as the control doubling time was calculated to be 2.05 days which met the test validity criteria of ≤2.5days. The pH and the temperature of the test solutions were both within the ranges outlined in the OECD 221 test guideline. The measured concentrations of CJ309 were within 80-120% of their nominal concentrations.

Based on the nominal concentrations of CJ309:

1.     The 7-Day EC50 for yield based on frond number was >100 mg/L. The NOEC and LOEC was 25 mg/L and 50 mg/L, respectively.

2.     The 7-Day EC50 for yield based on dry weight was >100 mg/L. The NOEC and LOEC was 6.25 mg/L and 12.5 mg/L, respectively.

3.     The 7-Day EC50 for Specific Growth Rate based on frond number was >100 mg/L. The NOEC and LOEC was 25 mg/L and 50 mg/L, respectively.

4.     The 7-Day EC50 for Specific Growth Rate based on dry weight was >100 mg/L. The NOEC and LOEC was 6.25 mg/L and 12.5 mg/L, respectively.