Reaction mass of 1,1'-(isopropylidene)bis[3,5-dibromo-4-(2,3-dibromo-2-methylpropoxy)benzene] and 1,3-dibromo-2-(2,3-dibromo-2-methylpropoxy)-5-{2-[3,5-dibromo-4-(2,3,3-tribromo-2-methylpropoxy)phenyl]propan-2-yl}benzene

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:

key study

Study period:

16 Aug - 12 Sep 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: SEPA, The Guidelines for the Testing of Chemicals, 2004, 201 Alga Growth Inhibition Test.

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: concentrations of the test substance determined at 0, 24, 48 and 72 hours of the test
- Sampling method: separation of algae from the test medium made by syringe filters
- Sample storage conditions before analysis: none

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: nominal concentration of 100 mg/L of the test substance was prepared and stirred (via magnetic stirrer) in the dark for 72 h at 500 rpm followed by filtration using a 0.451 μm nitrocellulose membrane to make a saturated solution of the test substance in the test water.

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Pseudokichnerella subcapitata
- Source (laboratory, culture collection): Institute of Hydrobiology, Chinese Academy of Sciences
- Age of inoculum (at test initiation): 3 days
- Method of cultivation: algae were inoculated in 250 mL glass flask with the concentration of 10^4 cells/mL, incubated in 3 days and then inoculated to another flask.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Post exposure observation period:

none

Test temperature:

23.3°C - 23.5 °C

pH:

7.74 - 9.12

Nominal and measured concentrations:

Range finding test: 0, 25, 50, 100 % of saturated solution
Limit test: 0, 100 mg/L (nominal, saturated solution)

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 ml glass conical flasks, closed with Parafilm, shaked at a speed of 130 rpm
- Initial cells density: 10^4 cells/mL
- Control end cells density: 1.22 x 10^6
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionized water

OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: no
- Photoperiod: continuous light
- Light intensity and quality: uniform fluorescent illumination; 5024 - 5497 Lux; cool white light

EFFECT PARAMETERS MEASURED:
- Determination of cell concentrations: counting chamber; at 0, 24, 48 and 72 hours

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 0, 25, 50, 100 % of saturated solution
- Results used to determine the conditions for the definitive study: EC50 > 100 % saturated solution

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: test material (saturated solution)

Basis for effect:

growth rate

Remarks on result:

other: Measured concentrations of the test substance were below the limit of detection of 89.6 ng/mL

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: test material (saturated solution)

Basis for effect:

growth rate

Remarks on result:

other: Measured concentrations of the test substance were below the limit of detection of 89.6 ng/mL

Details on results:

Based on growth rate and biomass: the 72h-ErC50 and LOEC values of the test substance to Pseudokirchneriella subcapitata was above the concentration of the saturated solution (measured concentration below the LOD2 of 89.6 ng/mL).

Results with reference substance (positive control):

EC50 (growth rate) = 0.83 mg/L

Reported statistics and error estimates:

The difference in the average specific growth rate between the control group and treatment groups were determined using t-Test.

Table 1. Cell density in limit test:

Treatment group	Cell density (cell/mL)
	0 h	72 h
Control	10000	1226167
100 mg/L (nominal, saturated solution)	10000	1172833

Table 2.Measured concentrations of the test substance in limit test:

Treatment group	Measured concentrations [mg/L]
	0 h	48 h
Control	not detected	not detected
100 mg/L (nominal, saturated solution)	not detected	not detected

Description of key information

EC50 (72 h) > 100 mg/L (nominal) for Pseudokirchneriella subcapitata based on growth rate (OECD 201)

LOEC (72 h) > 100 mg/L (nominal) for Pseudokirchneriella subcapitata based on growth rate (OECD 201)

Additional information

The toxicity of Reaction mass of 1,1'-(isopropylidene)bis[3,5-dibromo-4-(2,3-dibromo-2-methylpropoxy)benzene] and 1,3-dibromo-2-(2,3-dibromo-2-methylpropoxy)-5-{2-[3,5-dibromo-4-(2,3,3-tribromo-2-methylpropoxy)phenyl]propan-2-yl}benzene was tested on algae according to OECD 201 and GLP (Jing, 2014). The freshwater algae Pseudokirchneriella subcapitata was exposed to the test substance for 72 h, at the nominal test concentration of 100 mg/L. The test item solution was stirred and subsequently filtered in order to obtain a saturated solution as the test item is poorly soluble in saltwater. An analytical monitoring was performed via UPLC. Based on growth rate and biomass, the EC50 (72 h) and LOEC (72 h) values were above the concentration of the saturated solution (measured concentration below the LOD of 89.6 ng/mL).