Alkylbenzenesulphonic acid compound with alkanolamine

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Remarks:

the tested substance is the acid part of the compound

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

The concentration of the test substance in the test solution was analyzed at the beginning (0 hr) and at the end (72 hrs) of the test. About 2 mL sample (3 replicates) was taken from prepared vessels at 0 hours and at 72 hours, firstly 10 mL of test solutions of 3 flasks of each concentration were pooled and the solutions were centrifuged slightly(5000 rpm, 10 min) to remove grown algae. Upper phase of centrifuged solutions were taken and put into the analytical vial and then analyzed.

Vehicle:

yes

Details on test solutions:

Preparation method of test solution :After 103 mg of the test substance was added in a 1,000 mL beaker, and the dilution water (OECD nutrient medium) was added up to the mark of the beaker. This solution was then stirred for about 30 minutes. Serial dilutions of this test solution were prepared with the dilution water to give the desired series of exposure levels which were nominally 50, 25, 12.5 and 6.3 mg/L. For the control group, only the OECD culture medium was used. Test solution became turbid slightly but it was not filtered into consideration of characterization of test substance. This test substance is surfactant (by MSDS) and OECD document “Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures (OECD, 2000) recommend that separation techniques should not be applied to surfactant solution. Therefore, the filtration process was not performed for preparation of test solution.

Test organisms (species):

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

Details on test organisms:

Pseudokirchnerella subcapitata - Strain No. : UTEX 1648

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

Hardness (as CaCO3): 45.5 mg/L

Test temperature:

23.1 +/- 0.1 deg C

pH:

7.08-8.27

Nominal and measured concentrations:

Test concentrations were as follows :- Nominal : control, 6.3, 12.5, 25.0, 50.0 and 100.0 mg/L- Mean measured : control, 7.9, 15.1, 29.2, 56.1 and 101 mg/L

Details on test conditions:

- Medium : sterile OECD Nutrient medium (OECD TG, 2006)- Light intensity : 81- 89 μE/m2/s- Initial cell density : 5.0 × 103 cells/mL- Test design : 3 replicates

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

65.4 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 61.7-69.8

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

21 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 7.9-30.1

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

7.9 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

15.1 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

A 72 h NOEC of 7.9 mg/L has been determined for the effects of the test substance on growth rate of the Pseudokirchnerella subcapitata.

Validity criteria fulfilled:

yes

Conclusions:

The substance is less toxic to algae under the condition of the test.
A 72 h NOEC of 7.9 mg/L has been determined for the effects of the test substance on growth rate of the Pseudokirchnerella subcapitata.

Executive summary:

The study was conducted in accordance with the OECD TG 201 with Pseudokirchneriella subcapitata. It was performed with control and nominal concentrations of 6.3, 12.5, 25.0 and 100 mg/L each in triplicates. Cultures were incubated on a shaking incubator under continuous illumination at 23.1±1°C for 72 hours. Growth was monitored daily by determining the cell density of each culture by direct counts using a microscope. The 72hr-EC₅₀values of this study were 65.4 mg/L (measured) for average growth rate and 21.0 mg/L (measured) for yield respectively. The 72hr-NOEC values were 7.9 mg/L (measured) for average growth rate and yield.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Remarks:

the tested substance is the amine part of the compound

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study with acceptable restrictions (e.g. noanalytical verification of test concentrations, non-GLP)

Qualifier:

according to guideline

Guideline:

other: German industrial standard DIN 38412, part 9

GLP compliance:

no

Analytical monitoring:

no

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

125 mg/L

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

250 mg/L

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

219 mg/L

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

255 mg/L

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

339 mg/L

Basis for effect:

growth rate

Calculating effect values using ToxRatPro (v2.09):

The following nominal effect concentrations related to yield (EyC), growth rate (ErC), and biomass integral (EbC) were recalculated according to OECD TG 201 (adopted 23 Mar 2006) using the fluorescence values for inhibition of biomass from the original report. Since no calibration curve data were available, fluorescence data were equated with cell numbers (95 % confidence intervals in brackets):

Yield (mg/l)
------------------
EyC10:134.7  (63.2-174.6)
EyC20:167.2  (98.5-204.9)
EyC50:252.2  (206.2-309.0)

NOEyC:          62.5
LOEyC:          125.0
         

Growth rate (mg/l)
------------------
ErC10:219.1  (195.8-238.4)
ErC20:254.7  (233.4-273.2)
ErC50:339.3  (318.8-362.2)

NOErC:          250.0
LOErC:           125.0
          

Biomass integral (mg/l)
-----------------------
EbC10:           129.4  (19.6-178.8)
EbC20:           159.9  (44.0-207.5)
EbC50:           239.4  (166.7-338.2)

NOEbC:         125.0
LOEbC:          62.5


Original effect values as given in the report (nominal concentrations in mg/l):

         72 h
EC20: 160
EC50: 270
EC90: 470

pH at test start (0 h) and at test end (72 h)
---------------------------------------------
stock solution:
- pH 10.4 (conductivity: 47 µS/cm)
- pH adjusted: pH 8.2

Concentration [mg/L]	uninoculated		inoculated
	0 h	72 h	72 h
0 (Control)	8.2	8.3	9.2
62.5	9.0	8.3	9.3
125	9.4	8.4	9.2
250	9.6	8.7	9.0
500	9.8	9.0	9.0
500*	8.2	8.3	8.4

*: neutralised

 

No data were given on oxygen and temperature development during the test.

 

Description of key information

The EC50 values for growth rate of algae for the acid and amine were 65.4 mg/L (MOE 2008, measured) and 339 mg/L (BASF 1988, nominal) respectively. As the representative for the anionic part of the salt showed a higher toxicity compared to the representative for the cationic part. The EC50 of 65.4 mg/L is chosen to represent the toxicity of the salt in a worst case approach.

Key value for chemical safety assessment

EC50 for freshwater algae:

65.4 mg/L

EC10 or NOEC for freshwater algae:

7.9 mg/L