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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:

09 - 11 Mar 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

2017

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Version / remarks:

1996

GLP compliance:

yes (incl. QA statement)

Remarks:

National Institute of Pharmacy and Nutrition, Budapest, Hungary (issued: 2018-08-03)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Control and 100 mg/L nominal loading rates WAFs
- Sampling method: Analytical measurements were performed at the applied test concentration levels at the beginning and end of each renewal period, from the control at the beginning and end of experiment. Duplicate samples were taken (2 x ~15 mL) from the applied test concentration level and from the control (three replicates) from the stock solution at the beginning of the renewal periods and from the test at the end of the renewal periods.
- Sample storage conditions before analysis: Samples were frozen and kept approximately at -20°C at the Test Facility. One set of the samples was sent to the Test Site for analysis and one set was retained as a back-up at the Test Facility, if required for any confirmatory analyses.

Vehicle:

no

Details on test solutions:

-Method: The test item is poorly soluble in water, so test solutions were prepared using a saturated solution method (nominal loading rate of 100 mg/L, water accommodated fraction, WAF) according to the Guidance Document on Aqueous-Phase Aquatic Toxicity Testing of Difficult Test Chemicals, OECD No. 23. The saturated test item solution was prepared by dispersing/dissolving the amount of test item into the test medium (ISO-medium) two days before the start of the study. This solution was shaken for about 24 hours at approximately 30°C and then equilibrated for about 24 hours at approximately 20°C. The non-dissolved test material was removed by filtration through a fine (0.22 μm) filter. Prior to treatment of each renewal period, test item solutions were prepared by the method described above. The test solutions were prepared just before introduction of the Daphnia (start of the treatments).
-Control: Yes, dilution water (ISO-medium)

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Age at study initiation (mean and range, SD): < 24 h
- Method of breeding: The Daphnia are bred in Ecotoxicological Laboratory of Charles River Laboratories Hungary Kft. The health of the stock animals is continuously monitored by visual daily checking. Abnormal behaviour or significant decrease of population is recorded.
- Source: István Szent University, 2100 Gödöllő, Páter Károly u. 1, Hungary
- Feeding during test : No

ACCLIMATION
- Acclimation period: No

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

244 mg/L (as CaCO3)

Test temperature:

20.4 – 20.8°C

pH:

7.79 – 7.90

Dissolved oxygen:

7.1 – 8.5 mg/L

Nominal and measured concentrations:

- Nominal concentrations: 100 mg/L WAF
- Measured concentration: 0.08 mg/L (geometric mean)
- Further deatils see table 1 under "any other information on results incl. tables"

Details on test conditions:

TEST SYSTEM
- Test vessel: glass beakers
- Fill volume: approximately 40 mL
- Aeration: No
- Renewal rate of test solution (frequency/flow rate): 24 h
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: ISO-medium according to OECD guideline 202
- Culture medium different from test medium: No
- Intervals of water quality measurement: The water temperature was measured daily; the oxygen concentrations and pH of the control and the test solution were measured at the beginning and at the end of the renewal periods.

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 h light and 8 h darkness

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Immobility of daphnids was observed every 24 hours

VEHICLE CONTROL PERFORMED: no

RANGE-FINDING STUDY
- Test concentrations: 0.1, 1, 10, 100 mg/L nominal loading rates WAFs
- Results used to determine the conditions for the definitive study: No toxic response was observed during the range-finding study.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.08 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

>= 0.08 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: There were no effects at saturation with the test item.

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Relevant effect levels: The observed 24h EC50 value of the reference item was 0.82 mg/L, (95% confidence limits: 0.66 – 0.93 mg/L).
- Other: The experimental period of the last positive control study with reference item Potassium dichromate (Batch no.: A0345704) was 05 - 06 September 2019.

Reported statistics and error estimates:

No statistical analysis was performed because of the lack of toxic effects.

Table 1:Calculation of exposure concentrations

Nominal Loading rate WAFs (mg/L)	Measured concentrations 1st renewal period (mg/L)		Measured concentrations 2nd renewal period (mg/L)
	start	end	start	end
Control	<LOQ*	<LOQ*	<LOQ*	<LOQ*
100.0	0.064 0.091 0.087	0.049 0.053 0.059	0.094 0.126 0.095	0.078 0.081 0.088

*LOQ = 0.038 mg/L sample concentration (counting with 50x enrichment and 1.05x dilution during the sample preparation)

 

Table 2:Number and percentage of immobile daphnids

Nominal Loading rate WAF mg/L	Total number of animals	Number of immobilized animals
		24 h number	24 h percent	48 h number	48 h percent
Control	20	0	0	0	0
100	20	0	0	0	0

 

Table 3:Validity criteria

Criterion from the guideline	Outcome	Validity criterion fulfilled
In the control, including the control containing the solubilising agent, not more than 10% of the daphnids should have been immobilized.	0%	Yes
The dissolved oxygen concentration at the end of the test should be ≥ 3 mg/L in control and test vessels.	≥7.1 mg/L	Yes

 

Validity criteria fulfilled:

yes

Remarks:

See Table 3 at "any other information on results incl. tables"

Description of key information

EC50 (48 h) > 0.08 mg/L (measured geom. mean)

Additional information

There is one study available in which the short-term toxicity of Fatty acids, C16-18 (even numbered), esters with glycerol oligomers to aquatic invertebrates was assessed.

The GLP study was performed according to OECD 202 using Daphnia magna as test organism. A limit test with a nominal test concentration of 100 mg/L was conducted in a semi-static exposure regime. This test concentration was prepared as Water Accommodated Fraction (WAF). The test concentrations were analytically verified by GC-FID at the start and at the end of each renewal period. The test item concentration could be analytically quantified during the whole experiment, but the measured concentration was only slightly above the Limit of Quantification (LOQ = 0.038 mg/L). The corresponding measured geometric mean test item concentration was 0.08 mg/L. No effects were observed after 48 h. Therefore, an EC50 (48 h) of > 0.08 mg/L (measured geom. mean) was derived.