Reaction mass of mixed xylenes and sulphur monochloride

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:

17th August 2017 - 18th September 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Reaction Mass of Mixed Xylenes and Sulphur Monochloride

IUPAC Name:

Reaction Mass of Mixed Xylenes and Sulphur Monochloride

Test material form:

liquid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Batch 46000058
- Purity test date:Not applicable; substance is a UVCB


OTHER SPECIFICS:
Due to the low water solubility of the test item, a modification to the standard method of preparation for aqueous media was performed. The organisms were exposed to a Water Accommodated Fraction (WAF), as accepted by many regulatory authorities in the EU (ECETOC 1996, OECD 2000 and Singer et al 2000). Aqueous media are prepared by mixing test item with water for a prolonged period, the solution is left to settle and the test item phase siphoned off. The test organisms are exposed to the aqueous phase or WAF, containing dissolved test item and leachates from the test item. Exposure is expressed in terms of the original concentration of test item in water at the start of the mixing period irrespective of the dissolved fraction.

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples of the test solutions were taken at 0, 24, 48 and 72 hours and the cell densities determined by direct count using a Coulter Multisizer II electronic particle counter.
Water samples were taken from the control and the 100 mg ai/L test group at 0 and 72 hours for quantitative analysis of the test concentration.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Water Accommodated Fraction prepared over 23 hours. The WAF removed from mid-depth.

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata
- Strain: CCAP 278/4
- Source: Culture Collection for Algae and Protozoa (CCAP),SAMS Research Srevices Ltd, Scottish Marine Institute, Oban, Argyll, Scotland.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Test temperature:

21 ±1°C

pH:

The pH of the control and test solutions were 7.6 and 7.7 respectively at the start of the test.
The pH of the control and test solutions increased to 7.9 and 7.8 respectively at 72 hours.

Nominal and measured concentrations:

Nominal - 100 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 ml glass conical flasks
- Six flasks each containing 100 ml of test solution were prepared for both the treatment group and the control group.
- Mean cell density of control at 0 hours : 4.91 x 10 ^3cells/ml
- Mean cell density of control at 72 hours : 5.10 x 10^5cells/ml

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (total fraction)

Basis for effect:

growth rate

Effect concentrations 2

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (total fraction)

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (total fraction)

Basis for effect:

biomass

Effect concentrations 4

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (total fraction)

Basis for effect:

biomass

Results with reference substance (positive control):

- Results with reference substance valid? Yes
:

Reported statistics and error estimates:

Student t-Test

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 72 hour EC50 of 'Reaction mass of mixed xylenes and sulphur monochloride' was greater than 100 mg/l.

Executive summary:

A GLP study was performed in accordance with OECD guideline 201, in order to assess the effect of 'Reaction mass of mixed xylenes and sulphur monochloride' on the growth of the algae Pseudokirchneriella subcapitata.

Following a preliminary range finding study, Pseudokirchneriella subcapitata was exposed to the water accomodated fraction of the test substance at 100 mg ai/l for a period of 72 hours. Six replicates were performed at the test concentration and of the control solution. Samples of the algal populations were removed daily and cell concentrations determined for each control and treatment group. No effect on the algal growth was observed from the test solutions, therefore the EC₅₀ was defined as greater than 100 mg ai/L.