Sodium hydrogen N-(1-oxotetradecyl)-L-glutamate

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:

From January 20, 2016 to January 26, 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:

2012

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Quality Assesment can be found on page4 of the attached report

Specific details on test material used for the study:

Batch no.: 3837 supplied by the sponsor
25.5% in water as active ingredient (water solution), purity 100%
Solubility: soluble in water
Storage condition of test material: room temperature (15 °C - 25 °C)
Stability and homogeneity of the test material in the vehicle/solvent under test conditions (e.g. in the exposure medium) and during storage: stable for 12 months minimum
Solubility: soluble and stable in water
Reactivity of the test material with the incubation material used (e.g. plastic ware): not reactive
pH (20 °C) = 6.22
More information can be found on the attached report

Analytical monitoring:

yes

Remarks:

Determination of analytical concentration of total organic carbon (TOC), see details on sampling for more information

Details on sampling:

Samples, properly diluted with deionised water with low TOC contents, have been analysed by means of an integrated sampling system directly from vials containing 40 ml volume. For each sample under test the corresponding blank is analysed. The result is expressed corrected from the control and the deionised used for dilutions at initial and finaltiming test.
CALCULATIONS
% stability: 100 x (TOC substance 72h - (TOC ctl 72h - TOC deionized water 72h))/
(TOC substance 0h - (TOC ctl 0h - TOC deionized water 0h))
Samples are considered stable if the % stability is between 80 and 120% of the value.
STABILITY
The samples were stable throughout the test period.
Results that are summarized in table 4 of the attached report confirm stability.
Treated (100.00 cells/ml), at t0 51.64, at t72h 44.31, % stability 86
Treated (34.60 cells/ml), at t0 20.39, at t72h, % stability 104
Treated (11.97 cells/ml), at t0 10.49, at t72h 9.94, % stability 95

Vehicle:

no

Details on test solutions:

Culture medium has been prepared by mixing 4 stocks solution in order to obtain the following concentation:
SOLUTION N.1
NH4CI 0,75 g, CaCl2 2H20 0,9 g, MgCl2 6H20 0,6 g, MgSO4 7 H20 0,75 g, KH2PO4 0,08 g (dissolved in 500 ml of deionized water)
SOLUTION N.2
FeCl3 6H20 0,032 g, Na2EDTA 2H20 0,05 g (dissolved in 500 ml of deionized water)
SOLUTION 3
H3BO3 0,0925 g, MnCl2 4H20 0,207 g, ZnCl2 1 mL of the following solution: 150 mg in 100 mL
of deionized water, CoCl2 6H20 1 mL of the following solution: 75 mg in 100 mL of
deionized water, CuCl2 2 H20 1 mL of the following solution: 25 mg in 500 mL of deionized water, then dilution 1 ml of it in 10 ml, Na2MoO4 2H2O 1 mL of the following solution: 35 mg in 10 mL of deionized water (dissolved in 500 ml of deionized water)
SOLUTION 4
NaHCO3 25 g (dissolved in 500 ml of deionized water).
Solutions 1,2,3 have been sterilised by autoclaving (120 °C, 15 min). Solution 4 has been sterilised via membrane filtration (0.22 micrometer). 10 ml of solution 1 and 1 ml of solutions 2,3,4 have been made up to 1000ml with water.

Test organisms (species):

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

Details on test organisms:

Algal suspension kept in medium culture in sterile 250 mL Erlenmeyer
Starting cellular density: 10E+04
Number of replicates: 6 for control and 3 for treated
Temperature: 23 +/- 2°C
Lighting: > 4300 lux
Stirring: steady with electrical stirrer

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Remarks on exposure duration:

Steady stirring under continuos light

Test temperature:

The results of temperature during the whole test are reported in Attachment N. 2 -Table N. 3 of the attached report and satisfy the requirements of the guideline (23 +/- 2°C)

pH:

7.06 - 8.00
The results of pH at the beginning and at the end ofthe test are reported in Attachment N. 2 - Table N. 2A and 2B of the attached report and satisfy the requirements of the regulation (pH in the control must not deviate by more than 1.5 units during the test).

Nominal and measured concentrations:

Range finding test: from 0.1 to 1000 mg/L active ingredient
Definitive test: 0, 11.97, 20.35, 34.6, 58.82 and 100 mg/L active ingredient

Details on test conditions:

Starting cellular density: 10exp4 cell/ml
N. of replications: 6 for control and 3 for all treated concentrations in range finding and definitive test
Concentrations: for definitive tests following concentration tested were 100,00 mg/l, 58.82 mg/l, 34.60 mg/l, 20.35 mg/l and 11.97 mg/l in active matter.
Culture medium was used as control
Lightning: Continuous, with fluorescent lamp (8000 lux)
Stirring: Steady with electrical stirrer
Temperature: 23+/-2°C
Assay duration: 72+/-2 hours
The culture medium has been used as dilution water.
The test and control samples were incubated for a period of 72 + 2 h during which the cell density in each test and control solution was measured every 24 h by Burker chamber.
pH has been measured at the beginning and at the end of the assay.
Temperature of the ambient has been recorded at the beginning and every 24 hours.
At the end of the test the quality of algae appearance has been observed at microscopy.

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

81.34 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks:

inhibition

Details on results:

Average growth rate:
The average growth rate for a specific period (nij) is calculated as the logarithmic increase in the number of cells from the following equation for each control and treated vessel.
Calculate the average specific growth rate over the entire period using the nominally inoculated number of cell/ml as the starting value (Xi)
nij = (ln Xj - ln Xi)/( tj - ti)
Where
nij = is the average specific growth rate from time i to time j
Xi= is the numberof cell /ml at time i
Xj = is the numberof cell/ml at time j
The percent inhibition of growth rate was calculated as follows:
%Ir = [(nc - nt): nc] x 100
Whereas:
%Ir= percent inhibition in average specific growth rate
nc = mean value for average specific growth rate in the control group
nt = mean value for average specific growth rate in the treated group
VALIDITY
The assay is valid if the following criteria are satisfied:
-the cell concentration in the control cultures should have increased by a factor of at least 16 within three days, that corresponds to a specific growth rate of 0.92 day -1 (day 0-1 = 2.07, day 1-2 = 2.09 and day 2-3 1.50, all > 0.92)
-the mean coefficient of variation for section by section (CVss) specific growth rates in the control cultures must not exceed 35% (day 0-1 = 3.63, day 1-2 = 4.04 and day 2-3 6.27, all < 35%)
- the coefficient of variation of average specific growth rates during the whole period (CVwp) in replicate control cultures must not exceed 7% (1.22%).
All data can be found in Attachment 2 of attached report (Validity Criteria of the test)

Results with reference substance (positive control):

-

Interpretation of results:

The average growth rate as well as the percent of inhibition of growth rate were calculated.

Test substance EC50:

The value has been calculated by EPA Probit Program, version 1.5 (Attachment 3 of the attached report)

Validity criteria fulfilled:

yes

Conclusions:

Under the study conditions, the 72 h ErC50 of the substance in Pseudokirchneriella subcapitata was determined to be 81.34 mg a.i./L.

Executive summary:

A study was conducted to determine the short term toxicity of the substance to aquatic algae and cyanobacteria according to OECD Guideline 201, in compliance with GLP. Pseudokirchneriella subcapitata were exposed to the substance for 72 h at 0, 11.97, 20.35, 34.6, 58.82 and 100.0 mg/L. Total organic carbon (TOC) concentrations were measured with a TOC analyser and the test substance was considered stable over the duration of the test. The average growth rate as well as the percent of inhibition of growth rate were calculated. Under the study conditions, the 72 h ErC50 of the substance in Pseudokirchneriella subcapitata was determined to be 81.34 mg/L (Giarei, 2016).

Description of key information

EC50 (72h) = 81.34mg/L for Pseudokirchneriella subcapitata (OECD 201)

Key value for chemical safety assessment

EC50 for freshwater algae:

81.34 mg/L

Additional information

A study was conducted to determine the short term toxicity of the substance to aquatic algae and cyanobacteria according to OECD Guideline 201, in compliance with GLP. Pseudokirchneriella subcapitata were exposed to the substance for 72 h at 0, 11.97, 20.35, 34.6, 58.82 and 100.0 mg/L. Total organic carbon (TOC) concentrations were measured with a TOC analyser and the test substance was considered stable over the duration of the test. The average growth rate as well as the percent of inhibition of growth rate were calculated. Under the study conditions, the 72 h ErC50 of the substance in Pseudokirchneriella subcapitata was determined to be 81.34 mg/L (Giarei, 2016).