Benzene, mono-C10-13-alkyl derivs., distn. residues

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:

Feb. 16, 1993-Feb. 19. 1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study.

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Test substance was added to demineralized water at 1g/L and stirred for 18 hrs.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Source (laboratory, culture collection): Aus dem Institut fur Wasser-, Boden-, und Lufthygiene

Test type:

static

Total exposure duration:

72 h

Test temperature:

24 +/- 2°C

pH:

7.3 to 7.7 at test initiation and from 8.9 to 9.3 at 72-hours

Nominal and measured concentrations:

Nominal test concentrations were 0.23, 0.39, 0.69, 1.16 and 2.08 mg/L, plus a control.

Details on test conditions:

TEST SYSTEM
- Material, size, headspace, fill volume: Erlenmeyer flasks
- Initial cells density: 20,000 cells/ml
- No. of vessels per concentration (replicates): 8
- No. of vessels per control (replicates): 8


GROWTH MEDIUM
- Standard medium used: yes



OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Light intensity and quality: 8000 lux


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: spectrophotometer

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 2.08 mg/L

Nominal / measured:

nominal

Duration:

72 h

Dose descriptor:

other: EbC50

Effect conc.:

> 2.08 mg/L

Nominal / measured:

nominal

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

other: ErC50

Effect conc.:

> 2.08 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Cell Growth ( x 10⁴cells/ml)

Concentration	0 hrs	24 hrs	48 hrs	72 hrs
Control	2	6	24	69
0.23 mg/l	2	6	24	68
0.39 mg/l	2	6	24	79
0.69 mg/l	2	6	26	78
1.16 mg/l	2	6	26	80
2.08 mg/l	2	6	26	77

Validity criteria fulfilled:

yes

Conclusions:

The 72-hr ErC50 and EbC50 was > 2.08 mg/L test substance. This represents the solubility limit of the test substance.

Executive summary:

This study examined the potential of the test substance to cause toxicity to aquatic algae. Algae of the species Scenedesmus subspicatus were exposed to concentrations of 0, 0.23, 0.39, 0.69, 1.16 and 2.08 mg/L of test substance. The 2.08 mg/L concentration represents the solubility limit of the test substance. Algae were exposed for 72 hrs. Observations for biomass and growth rate were made at 24, 48, and 72 hrs after start of exposure. No reduction in either of these parameters as compared to controls was seen. The 72 -hr ErC50 and EbC50 was > 2.08 mg/L of test substance. The NOEC was >= 2.08 mg/L of test substance. The 72 -hr ErC50 and EbC50 are therefore greater than the solubility limit of the test substance.

Description of key information

The key study examined the potential of HAB to cause toxicity to aquatic algae. Algae of the species Scenedesmus subspicatus were exposed to concentrations of 0, 0.23, 0.39, 0.69, 1.16 and 2.08 mg/L of test substance. The 2.08 mg/L concentration represents the solubility limit of the test substance. Algae were exposed for 72 hrs. Observations for biomass and growth rate were made at 24, 48, and 72 hrs after start of exposure. No reduction in either of these parameters as compared to controls was seen. The 72 -hr ErC50 and EbC50 was > 2.08 mg/L of test substance. The NOEC was >= 2.08 mg/L of test substance. The 72-hr ErC50 and EbC50 are therefore greater than the solubility limit of the test substance.