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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Justification for type of information:
Dodecylbenzene sulfonic acids (CAS# 27176-87-0 , EC Number; 248-289-4) ) is a very close analogue of Calcium dodecylbenzenesulfonate (CAS No 26264-06-2, EC Number;247-557-8) ) and the dissociated acid it readily dissociates in water and release the dodecylbenzene sulfonic anion in solution.
Reason / purpose for cross-reference:
read-across source
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
not specified
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
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
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.

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
(Q)SAR
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
Justification for type of information:
QSAR prediction: US EPA accepted QSAR method for chemicals properties assessment.
Qualifier:
according to guideline
Guideline:
other: QSAR model
Principles of method if other than guideline:
ECOSAR Program(v1.00)
GLP compliance:
no
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
other: Green Algae
Details on test organisms:
QSAR model-Green Algae
Test type:
other: QSAR model
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Test temperature:
not applicable. QSAR model
pH:
not applicable. QSAR model
Dissolved oxygen:
not applicable. QSAR model
Salinity:
not applicable. QSAR model
Nominal and measured concentrations:
not applicable. QSAR model
Details on test conditions:
100% Benzenesulfonic acid, dodecyl-, calcium salt
CAS Number: 26264-06-2
SMILES : CCCCCCCCCCCCc1ccc(S(=O)(=O)OOS(=O)(=O)c2ccc(CCCCCCCCCCCC)cc2)cc1
CHEM : Benzenesulfonic acid, dodecyl-, calcium salt
MOL FOR: C36 H58 O6 S2 Ca1
MOL WT : 691.06
Wat Sol: 0.006264 (mg/L, EPISuite WSKowwin v1.43 Estimate)
Log Kow: 4.770
Remarks: Anionic surfactant – alkyl benzene sulfonates; effective alkyl chain length = C12


Reference substance (positive control):
no
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
2.736 mg/L
Nominal / measured:
not specified
Conc. based on:
not specified
Basis for effect:
not specified
Duration:
30 d
Dose descriptor:
NOEC
Effect conc.:
1.266 mg/L
Nominal / measured:
not specified
Conc. based on:
not specified
Basis for effect:
not specified
Remarks on result:
other: NOEC cited as a ChV value
Details on results:
Green Algae, 96-hr EC50 =2.736 mg/L (ppm)
Green Algae, 30-day, NOEC cited as a ChV value = 1.266 mg/L(ppm)

Overview of QSARs estimations onaquatic toxicity of 

Calcium dodecylbenzenesulphonate/ Benzenesulfonic acid, dodecyl-, calcium salt to Green algae

 

Method

 

Results

Remarks

Reference

QSAR

estimate

Green Algae, 96-hr EC50 =2.736 mg/L (ppm)

Green Algae, 30-day, NOEC cited as a ChV value = 1.266 mg/L (ppm)

 

Reliable with restrictions,

QSAR estimated data

ECOSAR Program (v1.00)

Green Algae, 96-hr EC50 =2.736 mg/L (ppm)

Green Algae, 30-day, NOEC cited as a ChV value = 1.266 mg/L (ppm)

Validity criteria fulfilled:
yes
Remarks:
method for chemicals properties assessment.
Conclusions:
Green Algae, 96-hr EC50 = 2.736 mg/L (ppm)
Green Algae, 30-day, NOEC cited as a ChV value = 1.266 mg/L (ppm)
Executive summary:

The ECOSAR QSAR model predicts that 30-day, NOEC cited as a ChV value would to be 1.266 mg/L (ppm) Green Algae.

The ECOSAR QSAR model predicts that 96-hr EC50 value would to be 2.736 mg/L (ppm) for Green Algae.

Description of key information

The ECOSAR QSAR model predicts that 30-day, NOEC cited as a ChV value would to be 1.266 mg/L (ppm) Green Algae. 
The ECOSAR QSAR model predicts that 96-hr EC50 value would to be 2.736 mg/L (ppm) for Green Algae.
A 72 h NOEC of 7.9 mg/L has been determined for the effects of the test substance (Dodecylbenzenesulphonic acid) on growth rate of the Pseudokirchnerella subcapitata.
The 72hr-EC50 values of this study were 65.4 mg/L (measured) for average growth rate and 21.0 mg/L (measured) for yield respectively.
A 96 h EC50 of 29 mg/L has been determined for the effects of the test substance (Dodecylbenzenesulphonic acid) on growth rate of the Selenastrum capricornutum (algae).
A 96 h EC50 of 29 mg/L has been determined for the effects of the test substance (C11.8 LAS) on growth rate of the Selenastrum capricornutum (algae).
he available data for saltwater algae and cyanobacteria are limited and to obtaine the value for PNECs for saltwaters is taken account a assesment factor 10 to extrapolate to LC50 following the “Guidance on Information Requirement and Chemical Safety Assessment R.10: Characterisation of dose [concentration]- response for environment”and “Table R.10-5 Assessment factors proposed for deriving PNEC water for saltwater for different data sets”, to account for the possibility that greater taxonomic diversity in the marine environment makes it likely that some marine taxa may be more sensitive than the most sensitive freshwater taxa

Key value for chemical safety assessment

EC50 for freshwater algae:
65.4 mg/L
EC50 for marine water algae:
6.54 mg/L
EC10 or NOEC for freshwater algae:
7.9 mg/L
EC10 or NOEC for marine water algae:
0.79 mg/L

Additional information

The ECOSAR QSAR model predicts that 30-day, NOEC cited as a ChV value would to be 1.266 mg/L (ppm) Green Algae.

The ECOSAR QSAR model predicts that 96-hr EC50 value would to be 2.736 mg/L (ppm) for Green Algae.

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

The 72hr-EC50 values of this study were 65.4 mg/L (measured) for average growth rate and 21.0 mg/L (measured) for yield respectively.

 

A 96 h EC50 of 29 mg/L has been determined for the effects of the test substance (Dodecylbenzenesulphonic acid) on growth rate of the Selenastrum capricornutum (algae).

A 96 h EC50 of 29 mg/L has been determined for the effects of the test substance (C11.8 LAS) on growth rate of the Selenastrum capricornutum (algae).

he available data for saltwater algae and cyanobacteria are limited and to obtaine the value for PNECs for saltwaters is taken account a assesment factor 10 to extrapolate to LC50 following the “Guidance on Information Requirement and Chemical Safety Assessment R.10: Characterisation of dose [concentration]- response for environment”and “Table R.10-5 Assessment factors proposed for deriving PNEC water for saltwater for different data sets”, to account for the possibility that greater taxonomic diversity in the marine environment makes it likely that some marine taxa may be more sensitive than the most sensitive freshwater taxa