Benzenethiol

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:

12 March 2001

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Benzenethiol

EC Number:

203-635-3

EC Name:

Benzenethiol

Cas Number:

108-98-5

Molecular formula:

C6H6S

IUPAC Name:

benzenethiol

Details on test material:

- Name of test material : benzenthiol
- Molecular formula : C6H6S
- Molecular weight : 110.18
- Substance type: liquid (a clear, colorless)
- Analytical purity: =>98.0%
The purity and molecular fomula were determined by IR, HPLC and NMR.
- Lot/batch No.:E99776L
- Storage condition of test material: at room temperature in the dark condition.

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
PHYSICO-CHEMICAL PROPERTIES
- Melting point: -14.8℃
- Boiling point: 168℃
- Vapour pressure:0.13kPa (18℃)
- Water solubility (under test conditions): 836mg/L (25℃)
- log Pow:2.52
- pKa: 6.62

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Sampling method:
Samples analysis were taken from all test concentrations and the control according to the schedule
below.
- Frequency: at t=0 h and t=72 h
- Volume: 0.2 mL ~ 1.0mL (0h), 1.0mL ~ 2.0mL (72h)

At the end of the exposure period, the replicates with algae were pooled at each concentration before sampling,
unless biological results of replicate vessels varied.
Compliance with the Quality criteria regarding maintenance of actual concentrations was demonstrated by running
a test vessel at the highest substance concentration but without algae and samples for analysis were taken at the
start, and at the end of the test period.

Test solutions

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION-
We used hydrogenated icinus (HCO-50) in order to homogenize test substance because test subustance was hardly solved in water.
Firstly the undiluted test solution (HCO-50 concentration :100 mg/L ) was prepared by mixing the medium and test substances, and filtered.
Secondly the test solution which was mixed the undiluted test solution with each test solution was prepared by adding the lack of HCO-50.
Finally test solution prepaird in second stage separated 4 test vessels each concentration and control.

Test organisms

Test organisms (species):

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

Details on test organisms:

- Strain: ATCC-22662
- Source : In-house laboratory culture
- Age of inoculum : three days culture bofore test initiation
- Method of cultivation: aseptic culture, passage culture
- Any deformed or abnormal cells observed: no. confirm transformation and abnormal cells by microscope

- Stock culture medium: M4
following composition:
----------------------------
H3BO3: 0.185 mg/l
MnCl2.4H2O: 0.415 mg/l
ZnCl2: 0.003 mg/l
FeCl3.6H20: 0.08 mg/l
Na2EDTA.2H20: 0.1 mg/l
CoCl2.6H20: 0.0015 mg/l
Na2MoO4.2H2O: 0.007 mg/l
CuCl2.2H2O: 0.00001 mg/l
CaCl2.2H2O: 18 mg/l
NH4Cl: 15 mg/l
KH2PO4: 1.6 mg/l
NaHCO3: 50 mg/l
MgCl2.6H2O: 12 mg/l
MgSO4.7H2O: 15 mg/l
----------------------------

Study design

Test type:

static

Water media type:

not specified

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

Not applicable

Test conditions

Hardness:

Not applicable

Test temperature:

23±2℃
The temparature during test was 22.2-22.9℃ and average temparature was 22.7℃.

pH:

pH7.6-7.7 (at before test) , pH7.8-9.0 (at ending test)

Dissolved oxygen:

Not applicable

Salinity:

Not applicable

Nominal and measured concentrations:

original setting concentration : control, 0.05 mg/L, 0.09mg/L, 0.16mg/L, 0.28mg/L, 0.50mg/L, 0.90mg/L
additional concentration : control, 1.62mg/L, 2.92mg/L, 5.26mg/L,

Details on test conditions:

Test vessels was sterikized and inoculation experiment was on the control of sterility.
(1) Incubatio : shaking culture (100rpm)
(2) Fluid volume of test solution : 100 mL (OECD medium)
(3) Lighting : 4000~5000 lux (continuous lighting)
(4) Initial cell density : An initial cell density of 1×10^4 cells/mL
(5) Analysis method : HPLC (the begging and ending of the test)

Reference substance (positive control):

yes

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.03 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other:

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.211 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other:

Remarks on result:

other: 95%(0.187mg/L~0.238mg/L)

Effect concentrations 3

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.765 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% (0.663mg/L~0.895mg/L)

Effect concentrations 4

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1.06 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% (1.00mg/L~1.12mg/L)

Effect concentrations 5

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.474 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 6

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1.03 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

See Attached document.
Mesured test substance concentrations: 0.003~1.96 mg/mL (0 h (hour)), (<0.0008mg/mL)~0.036mg/mL (72h),
The ratio of cocentration to original setting concentration (0.05~5.26mg/L) : 6.0~48.4% (0h), 0.7~2.1%,