Phosphorus tribromide

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:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Justification for type of information:

Data is from computational model developed by USEPA

Qualifier:

according to guideline

Guideline:

other: Modeling database

Principles of method if other than guideline:

Modelling Database - ECOSAR v.1.11

GLP compliance:

not specified

Specific details on test material used for the study:

- IUPAC name phosphorus(3+) tribromide
- Molecular formula: Br3P
- Molecular weight: 270.686 g/mol
- SMILES: P(Br)(Br)Br
- InChI: 1S/Br3P/c1-4(2)3
- Physical state: Liquid

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

other: green algae

Test type:

static

Water media type:

freshwater

Total exposure duration:

96 h

Remarks on exposure duration:

Estimated data

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

60.376 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Neutral Organic SAR (Baseline Toxicity)

Validity criteria fulfilled:

not specified

Conclusions:

Based on the prediction done using the EPI Suite ECOSAR version 1.10, the short term toxicity on green algae was predicted for test substance phosphorus(3 +) tribromide (CAS:7789 -60 -8). The estimated EC50 values for aquatic algae after 96 hours was 60.376 mg/l on the basis of growth rate.

Executive summary:

Based on the prediction done using the EPI Suite ECOSAR version 1.10, the short term toxicity on green algae was predicted for test substance phosphorus(3 +) tribromide (CAS:7789 -60 -8). On the basis of effects observed in a static freshwater system, the effect concentration EC50 value for the substance is estimated to be 60.376 mg/l for green algae for 96 hr duration. Based on this value, it can be concluded that the test chemical phosphorus(3 +) tribromide can be considered as toxic to green algae at environmentally relevant concentrations and can be considered to be classified in aquatic chronic category 3 as per the CLP classification criteria.

Description of key information

Based on the prediction done using the EPI Suite ECOSAR version 1.10, the short term toxicity on green algae was predicted for test substance phosphorus(3 +) tribromide (CAS:7789 -60 -8). On the basis of effects observed in a static freshwater system, the effect concentration EC50 value for the substance is estimated to be 60.376 mg/l for green algae for 96 hr duration. Based on this value, it can be concluded that the test chemical phosphorus(3 +) tribromide can be considered as toxic to green algae at environmentally relevant concentrations and can be considered to be classified in aquatic chronic category 3 as per the CLP classification criteria.

Key value for chemical safety assessment

EC50 for freshwater algae:

60.376 mg/L

Additional information

Various predicted data for the target chemical phosphorus tribromide (CAS No. 7789-60-8) and weight of evidence study for its read across substance were reviewed to summarize the following information:

 

Short term toxicity on aquatic algae and cyanobacteria of target chemical phosphorus tribromide (CAS No. 7789-60-8) is predicted using the using the EPI Suite ECOSAR version 1.10 (EPI Suite, 2017).On the basis of effects observed in a static freshwater system, the effect concentration EC50 value for the substance is estimated to be 60.376 mg/l for green algae for 96 hr duration.

 

In a weight of evidence study from secondary source (OECD SIDS, 2004) of the read across chemical Phosphorus trichloride (CAS no. 7719 -12 -2), short term toxicity to Scenedesmus subspicatus study was carried out for 72 hrs. The study was performed according to OECD Guideline 201 (Alga, Growth Inhibition Test) and EC Directive 92/69 C3, respectively. The study was based on the effects of the read across compound Phosphorus trichloride (CAS no. 7719 -12 -2) on Scenedesmus subspicatus (green algae) in a static fresh water system at a temperature of 21 – 25°C with light intensity of 60 -120 μE/m²/s, respectively. Scenedesmus subspicatus was used as a test organism. Initial cell density of the test organism was 10 × 10(4)cells/ml. Test chemical conc. used for the study were 3.13, 6.25, 12.5, 25, 50 and 100 mg/l (nominal concentrations), respectively. Experimental design consists of 6 test concentrations plus 1 control, 3 replicates per concentration, 6 replicates per control, highest test concentration without algae. 300 ml Erlenmeyer flasks with stoppers was used as a test vessels. pH is measured at the beginning of the test and at 72 h. Cell densities measured at 24 h intervals using a microcell counter. Inhibition of algal population measured as reduction in biomass growth (index b) and population density growth rate (index r), relative to control cultures under identical conditions. The 72 h-EC50 values are calculated or read from the concentration/percentage response curve. After 72 hours of exposure to Phosphorus trichloride, the NOEC and LOEC values was determined to be12.5 and 25 mg/l based on biomass and population density growth rate, the 72 hrs EC10 and EC50 value was determined to be 24.89 and 33.41 mg/l based on population density growth rate and on the basis of biomass, the 72 hr EC10 and EC50 value was determined to be 21.30 and 30.24 mg/l, respectively.

Thus, based on the overall reported results for target chemical phosphorus tribromide (EPI suite, 2017) and for its read across substance (from secondary source), it can be concluded that the test substance phosphorus tribromide can be considered as toxic to aquatic environment and can be considered to be classified in aquatic chronic category 3 as per the CLP classification criteria.