Bis(isopropyl)naphthalene

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:

Sept./Oct. 1990

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Remarks:

basic data given, accepable for assessment

Qualifier:

according to guideline

Guideline:

other: DIN 38412 part 9 (Determination of the inhibitory effect of aqueous constituents on green algae: Scenedesmus cell multiplication inhibition test)

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

(88/302/EEC, May 30, 1988)

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

(June 07, 1984)

Deviations:

yes

Remarks:

: only 2 replicates for test concentrations and for controls, no data and evaluation for validity criteria acc. to OECD TG 201

GLP compliance:

no

Analytical monitoring:

yes

Details on sampling:

- Only analytics of stock solution (saturated aqueous solution): see below

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The saturated stock solution (water-accommodated fraction) was prepared by mechanically stirring of a 500 µg DIPN per 1 L medium
for 48 h followed by separation of the insoluble material from the water phase using pre-conditioned glass fiber filter.
The stock solution was diluted with dilution water to the desired concentration.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: green algae
- Source (laboratory, culture collection): own culture
- Age of inoculum (at test initiation): 3 day old preculture
- Method of cultivation: no data

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

pH:

8.8 - 9.8

Nominal and measured concentrations:

measured concentration of stock solution: 0.19 mg/L (preparation see under "Details on test solutions")
test solutions: 80, 75, 70, 65, 60, 55, 50, and 40% dilutions of stock solution

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Initial cells density: 0.002 (absorbance at lamba = 578 nm)
- Control end cells density: 0.267 (absorbance at lamba = 578 nm)
- No. of organisms per vessel: initially approx. 10,000 cell/mL
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

GROWTH MEDIUM
- Standard medium used: yes (according to DIN 38412 part 9)

OTHER TEST CONDITIONS
- Test conditions: according to DIN 38412 part 9

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: absorbance at lambda = 578 nm:

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 0.94 - 1.1

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 0.15 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: only stock solution was analysed; effect concentration is 80% of stock solution concentration

Details on results:

- Exponential growth in the control (for algal test): yes
- Effect concentrations exceeding solubility of substance in test medium: no

No inhibitory effect was observed up to DIPN concentrations of 80% of a saturated solution.

Validity criteria fulfilled:

not specified

Conclusions:

In a freshwater alga growth inhibition test according to DIN 38412 part 9, no growth inhibition effect was observed up to DIPN test concentration close to its max. water solubility (ca. 0.15 to 0.19 mg/L).

Description of key information

Within the range of water solubility of diisopropylnaphthalene (0.1 to 0.2 mg/L), no inhibitory effect on growth rate of algae was observed (NOEC ca. 0.15 mg/L).

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:

0.15 mg/L

Additional information

For assessment of the toxicity to aquatic algae and cyanobacteria, one valid study is available.

 

 

Study	Test concentration	Result	Experimental conditions	Reliability
Vogel/UBA/KBwS/ WaBoLu 1999 (Scenedesmus subspicatus)	nominal: stock solution 0.19 mg/L test concentrations: 40, 50, 55, 60, 65, 70, 75, and 80% dilutions of stock solution	NOEC: ca. 0.15 mg/L (growth rate)	no vehicle 72 h static exponential growth	2