Hexanedioic acid, mixed esters with decanoic acid, heptanoic acid, octanoic acid and pentaerythritol

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:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Remarks:

Chemical analyses were based on limited number of measured WAF samples and analytical limit of GC detection in the WAF solutions was clearly below the WSL of test material. Percent inhibition based on AUC (area under curve) was not reported.

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Details on sampling:

- Concentrations: 0, 324, 1296 and 5076 mg/L (nominal concentration) exposure groups.
- Sampling method: samples collected at 0 and 72 hr for WAF solutions

Test organisms (species):

Selenastrum sp.

Details on test organisms:

TEST ORGANISM
- Strain: Selenastrum capricornutum

Test type:

static

Water media type:

other: algal medium

Total exposure duration:

72 h

Test temperature:

24 ± 1°C

pH:

pH 7.5 ± 0.1

Nominal and measured concentrations:

0, 324, 1296 and 5076 mg/L (nominal concentration)

Details on test conditions:

OTHER TEST CONDITIONS
- Adjustment of pH: pH 7.5 ± 0.1
- Photoperiod: continuous illumination
- Light intensity and quality: ~5000 lux
- other: continuously shaken at 100 rpm

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

974 mg/L

Nominal / measured:

nominal

Conc. based on:

other: WAF (nominal loading rate)

Basis for effect:

growth rate

Remarks on result:

other: see details on results

Details on results:

- Other: 1) WAF is the maximum soluble concentration of the nominal test concentrations after 20 hours of stirring and 4 hours of equilibrating. Only the water phase was taken and tested.
2) The analytical results indicate that test material in WAF solutions were below the 10 mg/L detection limit of the GC analytical method. The test material has limited water solubility (calculated to be 8.16 x 10-8 mg/L, using EpiWin).
3) Light intensity used was lower than recommended in the OECD 201 guideline. The test is still acceptable, since no effects on the cell growth were seen in the controls.

WAF Solution Conc.: Nominal load rate (mg/L)	At 72 hr: Mean Cell Density	Growth Rate: % Inhibition
0 Control (untreated)	1.06 x 105 cells/mL	-
324	5.52 x 104	47.96 %
648	6.38 x 104	39.90
1296	4.55 x 104	57.10
2592	1.46 x 104	86.27
5076	1.31 x 104	87.67

Validity criteria fulfilled:

yes

Conclusions:

72-hr EC50 was estimated to be 974 mg/L WAF (nominal loading rate)
The GC limit of detection in the WAF solutions was below the water solubility limit of the test material. The test substance has limited water solubility and would be expected to be close to water-saturated levels (WSL) in the tested solutions. The data suggest that test substance would not be expected to cause immobilization at or close to its water saturation levels or water solubility limits (WSL).

Key value for chemical safety assessment

EC50 for freshwater algae:

974 mg/L