Reaction products of n-octanol and acrylic acid, first distillation pitch

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From January 3, 2012 to February 24, 2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study was performed according to the OECD 202 Guideline and EU C.2 Method with GLP.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Qualifier:

according to guideline

Guideline:

ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Guidance document on aquatic toxicity testing of difficult substances and mixtures, OECD series on testing and assessment number 23, December 14, 2000.

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: all concentrations.
- Sampling method: Samples for Total Organic Carbon (TOC) analysis were controlled at 0 h and 48 h, with a volume of 40 mL.
- Sample storage conditions before analysis: Samples were stored in a refrigerator until analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:
The test substance was not completely soluble in test medium at the loading rates initially prepared.
Preparation of test solutions started with loading rates ranging from 1.0 to 100 mg/l applying an overnight period of magnetic stirring to reach maximum solubility of the test substance in the test medium. The resulting aqueous mixtures were left to stabilize for 2 to 2¾ hours were after the Water Accommodated Fractions (WAFs) were taken out by siphoning. The lowest test solution for the combined limit/range-finding test was prepared by a 10-fold dilution of the WAF prepared at a loading rate of 1.0 mg/l. All test solutions in the combined limit/range-finding test were clear and colourless besides the highest WAF that was very slightly hazy. In the final test the WAFs prepared at 10 and 18 mg/l were clear and colourless, whereas WAFs prepared at higher loading rates were hazy.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: daphnids.
- Source: In-house laboratory culture with a known history.
- Age at study initiation: < 24hours.
- Method of breeding:
Start of each batch: With newborn daphnids, i.e. less than 3 days old, by placing about 250 of them into 5 litres of medium in an all-glass culture vessel.
Renewal of the cultures: After 7 days of cultivation half of the medium twice a week.
Temperature of medium: 18-22°C.
Medium: M7, as prescribed by Dr. Elendt-Schneider (Elendt, B.-P., 1990: Selenium deficiency in Crustacea. An ultrastructural approach to antennal damage in Daphnia magna Straus. Protoplasma 154, 25-33).
- Feeding during test: No feeding.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

180 mg CaCO3 per litre

Test temperature:

19.6 - 20.3 ºC

pH:

7.7 - 8.1

Dissolved oxygen:

8.5 -9.3 mg/L

Nominal and measured concentrations:

WAFs prepared at loading rates of 10, 18, 32, 56 and 100 mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL.
- Material, size, headspace, fill volume: all-glass.
- Aeration: No aeration of the test solutions.
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Intervals of water quality measurement:
pH and dissolved oxygen: At the beginning and at the end of the test, for all concentrations and the control.
Temperature of medium: Continuously in a temperature control vessel, beginning at the start of the test.

OTHER TEST CONDITIONS
- Photoperiod: 16 hours photoperiod daily.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Immobility (including mortality): At 24 hours and at 48 hours.

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 10% of 1.0, 1.0, 10 and 100 mg/L.
- Results used to determine the conditions for the definitive study: Based on the obtained results the expected EL50 was between WAFs prepared at 10 and 100 mg/L.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

10 - 18 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Immobility:
One daphnid was immobilised in the control treatment. Note that the guideline allows up to 10% of immobilisation in the control treatment and therefore, the observed effect was not considered biologically significant.
Note that a floating layer of test substance was observed in all WAFs during the test. However, no test substance was observed on the bodies of the daphnids.
In the three highest groups all daphnids were immobilised. A dose response relationship was observed at the three lowest WAFs.

Results with reference substance (positive control):

- Results with reference substance valid? Yes, the 48h-EC50 was 0.28 mg/L with a 95% confidence interval between 0.26 and 0.32 mg/L.

Table 1. Acute immobilisation of daphnids after 24 and 48 hours in the final test.

Test substance^1 Loading rate^2 (mg/l)	Vessel number	Number Daphnia exposed	Response at 24 h		Response at 48 h
			number	Total %	number	Total %
control	A B C D	5 5 5 5	0 1 0 (1) 0 (1)	5	0 1 (1) 0 0 (1)	5
10	A B C D	5 5 5 5	0 0 0 0	0	2 1 0 0	15
18	A B C D	5 5 5 5	2 2 0 2	30	4 4 1 3	60
32	A B C D	5 5 5 5	4 2 2 4	60	5 5 5 5	100
56	A B C D	5 5 5 5	4 5 3 5	85	5 5 5 5	100
100	A B C D	5 5 5 5	5 5 (2) 5 (3) 5	100	5 5 5 5	100

¹ Reaction products of n-octanol and acrylic acid, first distillation pitch

² WAF prepared at given loading rate

( ) between brackets: number of daphnia observed trapped at the surface of the test solutions. These organisms were reimmersed into the respective solutions before recording of mobility.

Table 2. Effect parameters.

Parameter	Test substance^1 Loading rate^2 (mg/l)
24h-EL50	Between 18 and 32
48h-EL50	Between 10 and 18

¹ Reaction products of n-octanol and acrylic acid, first distillation pitch

² WAF prepared at given loading rate

Validity criteria fulfilled:

yes

Remarks:

(no more than 10% of the daphnids immobilised in the control; oxygen concentration ≥ 3 mg/L)

Conclusions:

The 48h-EL50 was between WAFs prepared at loading rates of 10 and 18 mg/L.

Executive summary:

The Acute Toxicity Study in Daphnia magna with the test solution was carried out according to OECD 202 Guideline and EU C.2 Method (GLP study).

 

As the test substance was not completely soluble in test medium at the loading rates initially prepared, the method Water Accommodated Fractions (WAFs) was used. The concentration of test substance in the aquatic samples was calculated using the TOC content of pure test substance.

 

The 48h-EL50 was between WAFs prepared at loading rates of 10 and 18 mg/L.

Description of key information

Key study: Experimental results: OECD 202 Guideline and EU C.2 Method. GLP study. 
The 48h-EL50 was between WAFs prepared at loading rates of 10 and 18 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

10 mg/L

Additional information

Key study: Experimental results: OECD 202 Guideline and EU C.2 Method. GLP study.

The 48h-EL50 was between WAFs prepared at loading rates of 10 and 18 mg/L.