Chlorodiphenylphosphine

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Chlorodiphenylphosphine

EC Number:

214-093-2

EC Name:

Chlorodiphenylphosphine

Cas Number:

1079-66-9

Molecular formula:

C12H10ClP

IUPAC Name:

diphenylphosphinous chloride

Test material form:

liquid

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

At the start and the end of the test.
Samples will be taken from all concentrations and the control

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A loading rate of 100 mg CHLORODIPHENYLPHOSPHINE per litre of test medium will be prepared and magnetically stirred for one day. The water saturated solution (SS) will be taken out by siphoning and used as the highest test concentration. Lower test concentrations will be prepared by proportional dilution of the SS in test medium.
The tests will be carried out without adjustment of the pH, except if pH values of test solutions are outside the optimal pH range for the species to be tested. No correction will be made for the purity/composition of the test item.
- Controls: Yes

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata
- Source (laboratory, culture collection): In-house laboratory culture.
- Age of inoculum (at test initiation):
- Method of cultivation: Algae stock cultures are started by inoculating growth medium with algal cells from a pure culture on agar. The suspensions are continuously aerated and exposed to light in a climate room at a temperature of 21-24°C.
- Light intensity 60 to 120 μE/m2/s when measured in the photosynthetically effective wavelength range of 400 to 700 nm.

- Stock culture medium M1; according to the NPR 6505, formulated using Milli-RO water
- Pre-culture 2 to 4 days before the start of the test, cells from the algal stock culture are inoculated in culture medium at a cell density of 1 x 104 cells/mL. The pre-culture is maintained under the same conditions as used in the test. The cell density is measured immediately before use.
- Pre-culture medium M2; according to the OECD 201 Guideline, formulated using Milli-RO

Study design

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Test conditions

Hardness:

24 mg CaCO3/L

Test temperature:

21-24 °C, constant within 2°C

pH:

Between 6.0 and 9.0

Salinity:

Not applicable, freshwater

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL, all-glass (standard)
- Initial cells density: An initial cell density of 1 x 104 cells/mL using an exponentially growing pre-culture.
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- pH: Between 6.0 and 9.0
- Photoperiod: Continuously using TLD-lamps with a light intensity within the range of 60 to 120 μE.m-2.s-1

EFFECT PARAMETERS MEASURED :
- Determination of cell concentrations: [counting chamber]

TEST CONCENTRATIONS
- Spacing factor for test concentrations:
- Justification for using less concentrations than requested by guideline:
- Range finding study
- Test concentrations:
- Results used to determine the conditions for the definitive study:

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

53 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

17 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the present study with Pseudokirchneriella subcapitata, the degradation product of CHLORODIPHENYLPHOSPHINE inhibited both growth rate and yield of this fresh water algae species at 6.5 mg/L and higher.

Executive summary:

Under the conditions of the present study with Pseudokirchneriella subcapitata, the degradation product of CHLORODIPHENYLPHOSPHINE inhibited both growth rate and yield of this fresh water algae species at 6.5 mg/L and higher.

·       The 72h-NOEC for growth rate inhibition was 2.2 mg/L when based on statistical analysis and 6.5 mg/L when based on biological relevance. 

·       The 72h-EC10 for growth rate inhibition (ERC10) was 17 mg/L with a 95% confidence interval ranging from 16 to 18 mg/L. 

·       The 72h-EC50 for growth rate inhibition (ERC50) was 53 mg/L with a 95% confidence interval ranging from 52 to 55 mg/L. 

·       The 72h-NOEC for yield inhibition was 2.2 mg/L when based on both statistical analysis and biological relevance. 

·       The 72h-EC10 for yield inhibition (EYC10) was 6.5 mg/L with a 95% confidence interval ranging from 5.8 to 7.2 mg/L. 

·       The 72h-EC50 for yield inhibition (EYC50) was 18 mg/L with a 95% confidence interval ranging from 17 to 18 mg/L.