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Toxicity to aquatic algae and cyanobacteria

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Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
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 limited documentation / justification
Justification for type of information:
Data is from OECD QSAR toolbox version 3.3 and the QMRF report has been attached.
Reference:
Composition 0
Qualifier:
according to
Guideline:
other: As mention below
Principles of method if other than guideline:
Prediction was done using the OECD QSAR toolbox version 3.3.
GLP compliance:
not specified
Test material information:
Composition 1
Specific details on test material used for the study:
- Name of test material : 2-ethoxynaphthalene-1-carbonyl chloride
- Molecular formula : C13H11ClO2
- Molecular weight : 234.681 g/mol
- Smiles notation : O=C(c1c2c(cccc2)ccc1OCC)Cl
- InChl : 1S/C13H11ClO2/c1-2-16-11-8-7-9-5-3-4-6-10(9)12(11)13(14)15/h3-8H,2H2,1H3
- Substance type: Organic
- Physical state: Solid
Analytical monitoring:
not specified
Vehicle:
not specified
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Test type:
static
Water media type:
freshwater
Total exposure duration:
72 h
Test temperature:
23.4 to 23.7ºC
pH:
7.30 to 7.65
Reference substance (positive control):
not specified
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
469.79 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: Other details not known
Details on results:
The EC50 at which 50% growth inhibited was 469.790 mg/l.

The prediction was based on dataset comprised from the following descriptors: EC50
Estimation method: Takes average value from the 6 nearest neighbours
Domain  logical expression:Result: In Domain

(((((((((((((((((((((("a" or "b" or "c" or "d" )  and ("e" and ( not "f") )  )  and "g" )  and "h" )  and "i" )  and "j" )  and "k" )  and ("l" and ( not "m") )  )  and "n" )  and "o" )  and "p" )  and "q" )  and "r" )  and "s" )  and ("t" and ( not "u") )  )  and "v" )  and "w" )  and ("x" and ( not "y") )  )  and "z" )  and "aa" )  and "ab" )  and ("ac" and "ad" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Acyl chloride OR Acyl halide OR Alkylarylether OR Aromatic compound OR Carbonic acid derivative OR Carboxylic acid derivative OR Ether OR Halogen derivative by Organic functional groups, Norbert Haider (checkmol) ONLY

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Aliphatic Carbon [CH] OR Aliphatic Carbon [-CH2-] OR Aliphatic Carbon [-CH3] OR Aromatic Carbon [C] OR Carbonyl, olefinic attach [-C(=O)-] OR Carbonyl, one aromatic attach [-C(=O)-] OR Chlorine, olefinic attach [-Cl] OR Miscellaneous sulfide (=S) or oxide (=O) OR Olefinic carbon [=CH- or =C<] OR Oxygen, one aromatic attach [-O-] by Organic functional groups (US EPA) ONLY

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Aliphatic Carbon [CH] OR Aliphatic Carbon [-CH2-] OR Aliphatic Carbon [-CH3] OR Aromatic Carbon [C] OR Carbonyl, olefinic attach [-C(=O)-] OR Carbonyl, one aromatic attach [-C(=O)-] OR Chlorine, olefinic attach [-Cl] OR Miscellaneous sulfide (=S) or oxide (=O) OR Olefinic carbon [=CH- or =C<] OR Oxygen, one aromatic attach [-O-] by Organic functional groups (US EPA) ONLY

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Acyl halide OR Alkoxy OR Aryl OR Ether OR Fused carbocyclic aromatic OR Naphtalene by Organic Functional groups ONLY

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Non binder, without OH or NH2 group by Estrogen Receptor Binding

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Non binder, impaired OH or NH2 group by Estrogen Receptor Binding

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Class 3 (unspecific reactivity) by Acute aquatic toxicity classification by Verhaar (Modified) ONLY

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Acid Halides by Aquatic toxicity classification by ECOSAR ONLY

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Acid Halides by Aquatic toxicity classification by ECOSAR ONLY

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Acid Halides by Aquatic toxicity classification by ECOSAR ONLY

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Acid Halides by Aquatic toxicity classification by ECOSAR ONLY

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Aromatic ether  [-O-aromatic carbon] AND Aromatic-H AND -CH2-  [linear] AND Methyl  [-CH3] AND Naphthalene AND Number of fused 6-carbon aromatic rings by Bioaccumulation - metabolism alerts

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as Alkyl substituent on aromatic ring by Bioaccumulation - metabolism alerts

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Bioavailable by Lipinski Rule Oasis ONLY

Domain logical expression index: "o"

Referential boundary: The target chemical should be classified as Not calculated by Biodeg BioHC half-life (Biowin) ONLY

Domain logical expression index: "p"

Referential boundary: The target chemical should be classified as Not calculated by Biodeg BioHC half-life (Biowin) ONLY

Domain logical expression index: "q"

Referential boundary: The target chemical should be classified as days - weeks by Biodeg primary (Biowin 4) ONLY

Domain logical expression index: "r"

Referential boundary: The target chemical should be classified as weeks - months by Biodeg ultimate (Biowin 3) ONLY

Domain logical expression index: "s"

Referential boundary: The target chemical should be classified as Acylation AND Acylation >> Direct Addition of an Acyl Halide AND Acylation >> Direct Addition of an Acyl Halide >> Acyl halide by DNA binding by OECD ONLY

Domain logical expression index: "t"

Referential boundary: The target chemical should be classified as Not possible to classify according to these rules by DPRA Cysteine peptide depletion

Domain logical expression index: "u"

Referential boundary: The target chemical should be classified as High reactive OR High reactive >> Vinyl pyridines by DPRA Cysteine peptide depletion

Domain logical expression index: "v"

Referential boundary: The target chemical should be classified as Not calculated by Hydrolysis half-life (Kb, pH 7)(Hydrowin) ONLY

Domain logical expression index: "w"

Referential boundary: The target chemical should be classified as Not calculated by Hydrolysis half-life (pH 6.5-7.4) ONLY

Domain logical expression index: "x"

Referential boundary: The target chemical should be classified as No Data by Ultimate biodeg

Domain logical expression index: "y"

Referential boundary: The target chemical should be classified as 10 to 100 days by Ultimate biodeg

Domain logical expression index: "z"

Referential boundary: The target chemical should be classified as Acid Halides by Aquatic toxicity classification by ECOSAR ONLY

Domain logical expression index: "aa"

Referential boundary: The target chemical should be classified as Acid Halides by Aquatic toxicity classification by ECOSAR ONLY

Domain logical expression index: "ab"

Referential boundary: The target chemical should be classified as High (Class III) by Toxic hazard classification by Cramer (with extensions) ONLY

Domain logical expression index: "ac"

Parametric boundary:The target chemical should have a value of log Kow which is >= -0.134

Domain logical expression index: "ad"

Parametric boundary:The target chemical should have a value of log Kow which is <= 3.6

Validity criteria fulfilled:
not specified
Conclusions:
The EC50 value was estimated to be 469.790 mg/l when 2-Ethoxy-1-naphthoyl Chloride exposed to Pseudokirchneriella subcapitata for 72 hrs.
Executive summary:

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the six closest read across substances, toxicity on Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) was predicted for 2-Ethoxy-1-naphthoyl Chloride (55150-29-3). The EC50 value was estimated to be 469.790 mg/l when 2-Ethoxy-1-naphthoyl Chloride exposed to Pseudokirchneriella subcapitata for 72 hrs. Based on this value it can be concluded that the substance 2-Ethoxy-1-naphthoyl Chloride is considered as nontoxic to aquatic environment as per the criteria mentioned in CLP regulation. 

Description of key information

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the six closest read across substances, toxicity on Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) was predicted for 2-Ethoxy-1-naphthoyl Chloride (55150-29-3). The EC50 value was estimated to be 469.790 mg/l when 2-Ethoxy-1-naphthoyl Chloride exposed to Pseudokirchneriella subcapitata for 72 hrs. Based on this value it can be concluded that the substance 2-Ethoxy-1-naphthoyl Chlorideis considered as nontoxic to aquatic environment as per the criteria mentioned in CLP regulation. 

Key value for chemical safety assessment

EC50/LC50 for freshwater algae:
469.79 mg/L

Additional information

Based on the various experimental data and prediction data for the target chemical as well as RA chemical which was selected on the basis of structure similarity study have been reviewed to determine the toxic nature of 2-Ethoxy-1-naphthoyl Chloride (55150-29-3) on the growth of algae. The studies are as mentioned below: 

In the first predicted weight of evidence report for the 2-Ethoxy-1-naphthoyl Chloride (55150-29-3) from SSS (QSAR, 2017) toxicity study was carried out. Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the six closest read across substances, toxicity on Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) was predicted for 2-Ethoxy-1-naphthoyl Chloride (55150-29-3). The EC50 value was estimated to be 469.790 mg/l when 2-Ethoxy-1-naphthoyl Chloride exposed to Pseudokirchneriella subcapitata for 72 hrs. Based on this value it can be concluded that the substance 2-Ethoxy-1-naphthoyl Chloride is considered as nontoxic to aquatic environment as per the criteria mentioned in CLP regulation. 

 

Similarly in the second weight of evidence study for the read across 1,1 -dimethylpropyl methyl ether (994-05-8), HSDB 2017. Short term toxicity to Pseudokirchneriella subcapitata study was carried out for 72 hrs. The study was based on the effects of the test compound 1,1 -dimethylpropyl methyl ether on Pseudokirchneriella subcapitata (green algae) in a static fresh water system at a temperature of 22.6 – 23.9°C and pH of 7.9 – 9.7, respectively. Pseudokirchneriella subcapitata (green algae) was used as a test organism at an initial cell density of 1 × 104cells/ml.Based on the effect on population abundance of test organism Pseudokirchneriella subcapitata, the 72 hr EC50 value was determined to be > 100 mg/l, respectively. Thus, based on the EC50 value, it can be concluded that the substance 1,1 -dimethylpropyl methyl ether can be considered as non-toxic to Pseudokirchneriella subcapitata at environmentally relevant concentrations and can be considered to be not-classified as per the CLP classification criteria.

 

Similarly in the third weight of evidence study for the read across chemical Phenyltrichlorosilane (98-13-5), SIDS dossier 2013. Short term toxicity study of the chemical Phenyltrichlorosilane on the growth of green algae was observed by the exposure of chemical for 72hrs. Test was performed by static method in Erlenmeyer flasks with different concentrations 0, 6.25, 12.5, 25.0, 50.0 and 100 mg/L. A 100 mg test item/L stock solution was prepared prior to test initiation by adding 176 μL of the dosing stock solution to 800 mL algal medium using a Hamilton syringe. Thereafter, the stock solution was further diluted to a final volume of 1000 mL with algal medium, resulting in a solvent (THF) concentration of 0.10 mL/L. initial cells density was394 x 104 cells/mL. Cell concentration and all other parameters was checked and maintained. The growth rate and biomass was observed in the interval of 24hrs. After the 72hrs of exposure the NOEC was ≥ 100 mg/l and the EC50 was > 100 mg/l on the basis of biomass and growth rate. Thus based on the EC50, the chemical was nontoxic and can be consider to be not classified as toxic as per the CLP classification criteria.

 

Similarly in the fourth weight of evidence study for the read across 1,1 -dimethylpropyl methyl ether (994-05-8), from OECD SIDS Initial Assessment Report 2005. Short term toxicity to Pseudokirchneriella subcapitata study was carried out for 72 hrs. The study was based on the effects of the test compound 1,1 -dimethylpropyl methyl ether (CAS no. 994 -05 -8) on Pseudokirchneriella subcapitata (green algae) in a static fresh water system. Pseudokirchneriella subcapitata (green algae) was used as a test organism. Based on the effect on biomass and growth rate of test organism Pseudokirchneriella subcapitata, the 72 hr EC50 value was determined to be 230 and 780 mg/l and the 72 hr NOEC value was determined to be 77 mg/l, respectively. Thus, based on the EC50 value, it can be concluded that the substance 1,1 -dimethylpropyl methyl ether can be considered as non-toxic to Pseudokirchneriella subcapitata at environmentally relevant concentrations and can be considered to be not-classified as per the CLP classification criteria.

 

Thus based on the above data sources for target chemical 2-Ethoxy-1-naphthoyl Chloride (55150-29-3)  from various experimental studies and predicted studies from QSAR, HSDB, and OECD SIDS dossier it was summarized that the chemical was nontoxic and can be consider to be not classified as toxic as per the CLP classification criteria.