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Short-term toxicity to aquatic invertebrates

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Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Justification for type of information:
The source compound Benzyl 4-hydroxybenzoate (EC 202-311-9, CAS 94-18-8) is considered a suitable read across partner for the target substance Phenyl 4-hydroxybenzoate (EC 241-698-9, CAS 17696-62-7). This read-across is based on the hypothesis that source and target substances have similar toxicological properties because:

- structural similarity of the target and the source substances (the presence or absence of additional functional groups or substituents that could influence the behaviour of a chemical),
- similarity in physico-chemical profile of the source and target substances (water solubility, partitioning behaviour (log Kow value))
Both substances are structural homologues regarding the functional groups at the ester (phenyl vs benzyl group). Both esthers have similar physico-chemical properties. Both are moderately/poorly water soluble (108 g/L vs 0.05 mg/L), exhibit similar log Kow values (3.97 vs 3.21), have similar boiling points (355 °C vs 241 °C) and vapour pressure (3.37x10-6 mm Hg vs 8.17x10-6 mm Hg).
Reason / purpose:
read-across source
Vehicle:
yes
Key result
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
4 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
other: 5 nominal concentration was used but exact values not specified
Details on results:
dissolved oxygen of water =7.1 to 9.0 mg/L
Reported statistics and error estimates:
For all acute tests, LC50 values were calculated for each paraben using the probit method, if assumptions were met, or a trimmed Spearman–Karber method, if assumptions for the probit method were not met. Because all acute tests were run in
triplicate, the average LC50 value from the three exposures was calculated

All calculations of LC50 values were based on nominal concentrations. Control mortality in RHW and solvent never exceeded 10%. Additionally, there was no significant difference ( p .0.05) between the RHW control and solvent control in any test. In both species, significant relationships (p ,0.01) between log P and LC50 values for the parabens were demonstrated (Fig. 2A). During the acute studies, organisms were first observed either immobilized or sluggish, and with time, the parabens ultimately led to the death of the organism.

Validity criteria fulfilled:
not specified
Conclusions:
The LC50 value for Daphnia magna for benzyl 4-hxdroxybenzoate (CAS# 94-18-8) was determined with 4.0 mg/L.
Executive summary:

The 48-hr-acute toxicity of benzyl 4-hydroxybenzoate to Daphnia magna was studied under static conditions and conducted according to OECD guideline 202.Test specieswere exposed to control, solvent control, and test chemical at five concentrations for 48 hr.  Mortality and immobilisation were observed daily. The 48-hour LC50was 4.0 mg a.i./L. 

 

This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

 

Results Synopsis

 

Test Organism Age (e.g. 1stinstar): < 24 h

Test Type (Flowthrough, Static, Static Renewal): static

 

LC50:  4.0 mg/L

Endpoint(s) Effected:  mortality and immobility

This information is used in a read-across approach in the assessment of the target substance.

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
The source compound Benzyl 4-hydroxybenzoate (EC 202-311-9, CAS 94-18-8) is considered a suitable read across partner for the target substance Phenyl 4-hydroxybenzoate (EC 241-698-9, CAS 17696-62-7). This read-across is based on the hypothesis that source and target substances have similar toxicological properties because:

- structural similarity of the target and the source substances (the presence or absence of additional functional groups or substituents that could influence the behaviour of a chemical),
- similarity in physico-chemical profile of the source and target substances (water solubility, partitioning behaviour (log Kow value))
Both substances are structural homologues regarding the functional groups at the ester (phenyl vs benzyl group). Both esthers have similar physico-chemical properties. Both are moderately/poorly water soluble (108 g/L vs 0.05 mg/L), exhibit similar log Kow values (3.97 vs 3.21), have similar boiling points (355 °C vs 241 °C) and vapour pressure (3.37x10-6 mm Hg vs 8.17x10-6 mm Hg).
Reason / purpose:
read-across source
Key result
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
2.1 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks:
numbers of immobilized bodies
Remarks on result:
other: 5 concentrations mention but values was not specified
Validity criteria fulfilled:
not specified
Conclusions:
The EC50 value of benzyl 4-hydroxybenzoate (CAS # 94-18-8) for Daphnia magna was determined with 2.1 mg/L.
Executive summary:

The 48-hr-acute toxicity of benzyl 4-hydroxybenzoate to Daphnia magna was studied under static conditions according to the OECD guideline 202. Test specieswere exposed to control and test chemical at five different concentrations for 48 hr.  Mortality and immobilisation were observed daily. The 48-hour LC50/EC50was 2.1 mg a.i./L.

  

This study is classified as acceptable/unacceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

 

Results Synopsis

 

Test Organism Age (e.g. 1stinstar): < 24 h

Test Type (Flowthrough, Static, Static Renewal): static

 

LC50:  2.1 mg a.i./L

Endpoint(s) Effected: mortality, immobility

This information is used in a read-across approach in the assessment of the target substance.

Description of key information

Two short-term toxicity studies with Daphnia magna according to OECD guideline 202 are available deriving the following effect concentrations:

48 -h LC50 = 2.2 mg/L (Yamamoto et al. 2011)

48 -h LC50 = 4.0 mg/L (Dobbins et al. 2009)

The lower value is set as key value.

This information is used in a read-across approach in the assessment of the target substance.

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
2.1 mg/L

Additional information


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