Sodium 6-amino-5-[[2-[(cyclohexylmethylamino)sulphonyl]phenyl]azo]-4-hydroxynaphthalene-2-sulphonate

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:

2014

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)

Deviations:

yes

Remarks:

No major deviations to the guideline (pH of the control increased by more than 1.5 units on day 5. The test is still valid, as it was shown that validity criteria are met).

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Name: FAT 20003/K TE
Batch number: AT-0026132600
EAS Test item code: 2014-000180
Appearance / colour: solid / brown
Content of a.i. nominal : > 90 %w/w
Molecular weight : 517.60 g/mol (base), 540.59 g/mol (salt)
Date of analysis : 07 Jan 2014.
Expiry date : 20 Dec 2018
Storage conditions : ambient (+5 to +30°C), dark, dry

Analytical monitoring:

yes

Details on sampling:

After sampling, the test medium samples (0.5 mL) were mixed with 0.5 mL methanol and stored deep-frozen (below -18 °C) until analysis.

Vehicle:

no

Details on test solutions:

The necessary amount of test item for preparing the stock solution S1 was weighed and transferred to a volumetric flask. Test medium was added up to the bench mark and the solution was homogenised by shaking. Lower concentrations of the test item were prepared by dilution of the stock solution.

Test organisms (species):

Lemna gibba

Details on test organisms:

(Alismatales: Araceae). The plants used in this study were taken as aseptic clones from the cultivation of the testing facility. They were primarily cultured by Dr. Janet Slovin, Horticulture Crops Quality Laboratory, U.S. Department of Agriculture. BARC-West, Bldg. 050 HH-4, Beltsville, MD 20705, U.S.A.
The plants were cultured in appropriate glass beakers under continuous illumination with OSRAM light tubes (L30/32-930 and L30/W72-965), at 6500 - 7000 lux. The temperature was 24 ± 2 °C. Before the test was started, plants were cultured under the same illumination and temperature conditions as those to be used for the toxicity test. Young, light-green plants of similar size and comprising 2 - 5 fronds were transferred onto fresh medium and cultured for 3 weeks prior to testing, with two further transfers onto fresh medium before initiating the test.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

7 d

Nominal and measured concentrations:

see table below

Details on test conditions:

Test procedure: semi-static test
Duration: 7 days
Temperature: 22.0 – 24.7 °C
pH-value of fresh solution: 7.47 – 7.64
Light intensity (mean): ~ 6800 lux
Light tubes: OSRAM light tubes (L 30 W77 and L 30 W25)
Exposure to light: continuously
Test vessels: 250 mL glass beakers filled with 150 mL
Number of fronds: 12 per test vessel

Duration:

7 d

Dose descriptor:

EC10

Effect conc.:

19.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield of frond number

Duration:

7 d

Dose descriptor:

EC20

Effect conc.:

32.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield of frond number

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

69.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield of frond number

Duration:

7 d

Dose descriptor:

NOEC

Effect conc.:

31.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield of frond number

Duration:

7 d

Dose descriptor:

LOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield of frond number

Duration:

7 d

Dose descriptor:

EC10

Effect conc.:

35.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth rate of frond number

Duration:

7 d

Dose descriptor:

EC20

Effect conc.:

55.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth rate of frond number

Key result

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth rate of frond number

Duration:

7 d

Dose descriptor:

NOEC

Effect conc.:

31.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth rate of frond number

Duration:

7 d

Dose descriptor:

LOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth rate of frond number

Duration:

7 d

Dose descriptor:

EC10

Effect conc.:

14.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield of dry weight

Remarks on result:

other: 1.28-28.0

Duration:

7 d

Dose descriptor:

EC20

Effect conc.:

23.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield of dry weight

Remarks on result:

other: 4.48-40.3

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

50.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield of dry weight

Remarks on result:

other: 26.6 – 84.8

Duration:

7 d

Dose descriptor:

NOEC

Effect conc.:

9.77 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield of dry weight

Duration:

7 d

Dose descriptor:

LOEC

Effect conc.:

31.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield of dry weight

Duration:

7 d

Dose descriptor:

EC10

Effect conc.:

26.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth rate of dry weight

Remarks on result:

other: 19.0-33.6

Duration:

7 d

Dose descriptor:

EC20

Effect conc.:

41.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth rate of dry weight

Remarks on result:

other: 32.8-48.8

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

79.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth rate of dry weight

Remarks on result:

other: 69.8 – 91.8

Duration:

7 d

Dose descriptor:

NOEC

Effect conc.:

9.77 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth rate of dry weight

Duration:

7 d

Dose descriptor:

LOEC

Effect conc.:

31.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth rate of dry weight

Reported statistics and error estimates:

The statistical evaluation for day 7 was performed for yield of frond numbers, growth rate of frond numbers, growth rate dry weight and yield of dry weight. A test for normality of the data was performed by calculating the Shapiro-Wilk’s statistic, a test for homogeneity of the data was performed according to Levene. The NOEC and LOEC were determined by using a multiple comparison method (Dunnett`s t-test and Jonckheere-Terpstra). The EC10, EC20 and EC50 values for yield of frond number, yield of dry weight and growth rate of dry weight were determined by probit analysis following Gompertz procedure. Negative values were set to zero. The calculation of EC50 values for growth rate of frond numbers was not indicated since inhibition was below 50 %. The evaluation of data was performed by SAS® (2002-2010).

Validity criteria fulfilled:

yes

Conclusions:

Significant inhibitory effects were determined for yield of frond numbers and for growth rate of frond numbers at 100 mg/L (nominal). Significant inhibitory effects were determined for yield of dry weight and for growth rate of dry weight at 31.3 and 100 mg/L. The overall LOEC was therefore determined to be 31.3 mg/L, the corresponding NOEC at 9.77 mg/L.
The nominal EC10-value for yield of frond numbers was determined to be 19.9 mg/L, the nominal EC10-value for yield of dry weight was determined to be 14.4 mg/L. The nominal EC10-value for growth rate of dry weight was determined to be 26.7 mg/L. The nominal EC10-value for growth rate of frond numbers was determined to be 35.8 mg/L.
The nominal EC20-value for yield of frond numbers was determined to be 32.7 mg/L, the nominal EC20-value for yield of dry weight was determined to be 23.8 mg/L. The nominal EC20-value for growth rate of dry weight was determined to be 41.3 mg/L. The nominal EC20-value for growth rate of frond numbers was determined to be 55.8 mg/L.
The nominal EC50-value for yield of frond numbers was determined to be 69.5 mg/L, the nominal EC50-value for yield of dry weight was determined to be 50.6 mg/L. The nominal EC50-value for growth rate of dry weight was determined to be 79.8 mg/L. The nominal EC50-value for growth rate of frond numbers was determined to be >100 mg/L.
The test is valid as the doubling time of control frond numbers was calculated to be 47.7 h, corresponding to 1.987 days at day 7. This is less than the maximum allowable doubling time set in OECD guideline 221 (60 h, 2.5 days).

Executive summary:

The aim of the study was to assess the effect of the test item on the growth of Lemna gibba according to OECD Guideline 221 and derive EC10, 20, 50 and NOEC/LOEC values.

A semi-static main test with nominal concentrations of 0 (control), 0.954, 3.05, 9.77, 31.3 and 100 mg/L was performed.

Vegetative growth was observed for a test period of 7 days by measuring the increase of frond numbers and dry weight. The following endpoints (NOEC/LOEC, EC10, 20, 50) were determined:

- frond numbers and dry weight

- growth rates of frond numbers and dry weight

- yield of frond numbers and dry weight

- doubling times of frond numbers

Findings:

The initial mean measured concentration of FAT 20003/K TE in the test item solutions was 99 % of nominal. The overall mean concentration of fresh and aged samples was 96 % of nominal. Toxicological endpoints were evaluated using nominal concentrations of the test item.

Toxicological endpoints for FAT 20003/K TE:

Significant inhibitory effects were determined for yield of frond numbers and for growth rate of frond numbers at 100 mg/L (nominal). Significant inhibitory effects were determined for yield of dry weight and for growth rate of dry weight at 31.3 and 100 mg/L. The overall LOEC was therefore determined to be 31.3 mg/L, the corresponding NOEC at 9.77 mg/L.

The nominal EC10-value for yield of frond numbers was determined to be 19.9 mg/L, the nominal EC10-value for yield of dry weight was determined to be 14.4 mg/L. The nominal EC10-value for growth rate of dry weight was determined to be  26.7 mg/L. The nominal EC10-value for growth rate of frond numbers was determined to be 35.8 mg/L.

The nominal EC20-value for yield of frond numbers was determined to be 32.7 mg/L, the nominal EC20-value for yield of dry weight was determined to be 23.8 mg/L. The nominal EC20-value for growth rate of dry weight was determined to be  41.3 mg/L. The nominal EC20-value for growth rate of frond numbers was determined to be 55.8 mg/L.

The nominal EC50-value for yield of frond numbers was determined to be 69.5 mg/L, the nominal EC50-value for yield of dry weight was determined to be 50.6 mg/L. The nominal EC50-value for growth rate of dry weight was determined to be 79.8 mg/L. The nominal EC50-value for growth rate of frond numbers was determined to be >100 mg/L.

Description of key information

The nominal EC10-value for yield of frond numbers was determined to be 19.9 mg/L, the nominal EC10-value for yield of dry weight was determined to be 14.4 mg/L. The nominal EC10 value for growth rate of dry weight was determined to be 26.7 mg/L. The nominal EC10-value for growth rate of frond numbers was determined to be 35.8 mg/L.

The nominal EC50-value for yield of frond numbers was determined to be 69.5 mg/L, the nominal EC50-value for yield of dry weight was determined to be 50.6 mg/L. The nominal EC50 - value for growth rate of dry weight was determined to be 79.8 mg/L. The nominal EC50-value for growth rate of frond numbers was determined to be >100 mg/L.

The test is valid as the doubling time of control frond numbers was calculated to be 47.7 h, corresponding to 1.987 days at day 7. This is less than the maximum allowable doubling time set in OECD guideline 221 (60 h, 2.5 days).

Key value for chemical safety assessment

EC50 for freshwater plants:

100 mg/L

EC10 or NOEC for freshwater plants:

35.8 mg/L