2,2'-dithiodi(benzoic acid)

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

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

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:

2,2'-dithiodi(benzoic acid)

EC Number:

204-352-8

EC Name:

2,2'-dithiodi(benzoic acid)

Cas Number:

119-80-2

Molecular formula:

C14H10O4S2

IUPAC Name:

2-[(2-carboxyphenyl)disulfanyl]benzoic acid

Test material form:

other: Solid

Details on test material:

The test material had a purity of 75.7%

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

-cell density determinations: Coulter counter model ZB counting at lower threshoold equivalent spherical diameter of 2.3um
-sampling interval: 24, 48, 72h

Test solutions

Details on test solutions:

-dose preparation: 1600ml of 96mg/l test substance solution was prepared by direct addition to sterile culture medium. All lower test concentrations were prepared by diluting requisite volume of 96mg/l solution to 1l sterile medium.

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
-Strain: ATCC22662
- Source (laboratory, culture collection): laboratory culture

Study design

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Test conditions

Test temperature:

23-25degreesC

pH:

-method: Corning Model 240 pH meter
-4.5-9.6

Nominal and measured concentrations:

-nominal: 0, 0.75, 1.5, 3.0, 6.0, 12, 24, 48, 96mg/l
-measured: 0.94, 1.4, 2.7, 5.7, 12, 30, 41, 60mg/l

Details on test conditions:

-test vessels: 250ml glass beakers containing 100ml test solution
-incubation: continuous "cool-white" illumination with orbital shaking at 160rpm
-replicates/test concentration: 3
-nominal cell density: 1x10E4 cells/ml

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

22 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

biomass

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

34 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

12 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

other: Biomass and growth rate

Any other information on results incl. tables

Mean cell densities:

Nominal conc (mg/l)	Algal cell density (x10E4 cells/ml)
	24h	48h	72h
0	7.7	54.3	237
0.75	7.64	53.0	233
1.5	7.54	56.8	245
3.0	7.24	52.2	233
6.0	7.05	49.8	224
12	6.81	46.5	219
24	4.42	25.2	133
48	1.77	1.67	2.17
96	1.33	1.55	1.45

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 72 hour EbC50 for algae is 22 mg/l and the ErC50 is 34 mg/l. The 72 hour NOEC was 12 mg/l.