[No public or meaningful name is available]

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:

28 April 2017 to 1 June 2017

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)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

excess test solutions were sampled and at the end of the test one replicate of the dilution water control, solvent control and each test concentration was sampled
- Concentrations: all concentrations
- Sampling method: from excess test solutions at the start of the test and from one replicate of the dilution water control, solvent control and each test concentration at the end of the test
- Sample storage conditions before analysis: no data

At the end of the tests all test concentration vessels were rinsed with 20 ml of 0.5 mg/l Phenanthrene in hexane and an aliquot transferred to an auto-sampler vial for analysis

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION A primary stock concentrate of the substance with a nominal concentration of 500 g/L, was prepared by weighing a nominal 5 g of test substance and making up to 10 mL with the solvent tetrahydrofuran (THF) in a volumetric flask. The resultant stock was observed to be a clear and colourless solution and was used to prepare the test solutions. THF concentration in controls and exposure solutions was 0.1 mg/L.

Test solutions at 0.3125, 0.625, 1.25 mg/Lwere clear at t=0, but at 1.25 mg/L globules of the substance on the surface were seen at 24 and 48 hours, Test solutions at 2.5 and 5.0 mg/L contained globules of the substance on the surface at all obeservation times.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Source: laboratory cultures held at Scymaris
- Age of parental stock (mean and range, SD): 12 ± 1 day
- Feeding during test: none

ACCLIMATION
- Acclimation period: NA
- Stock conditions (same as test or not): in a reconstituted water medium, the same as the test dilution water, at a temperature of 20 ± 2°C.
- Type and amount of food: mixed algae diet of Chlorella vulgaris and Pseudokirchneriella subcapitata
- Feeding frequency: daily
- Health during acclimation: no evidence of disease:

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

230 mg/L as CaCO3

Test temperature:

19.7 - 20.5 °C

pH:

7.8-7.9

Dissolved oxygen:

9.0-9.2 mg/L

Conductivity:

620 µS/cm

Nominal and measured concentrations:

nominal: 0, 0.3125, 0.625, 1.25, 2.5 and 5.0 mg/L
measured: LOQ, 0.16, 0.44, 0.62, 1.4 and 2.1 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL glass beaker with 200 mL test solution
- Type: closed (loss fitting glass lid)
- Aeration: none
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates):4
- No. of vessels per vehicle control (replicates):4

TEST MEDIUM / WATER PARAMETERS: ELENDT M4 reconstituted water according to the guideline

OTHER TEST CONDITIONS
- Adjustment of pH: none
- Photoperiod: 16 h light/8 h dark

EFFECT PARAMETERS MEASURED: immobility at 24 and 48 hours

VEHICLE CONTROL PERFORMED: yes

RANGE-FINDING STUDY:not performed

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

2.1 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 2.1 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mobility

Details on results:

No immobility was observed in any of the test vessels at any concentration tested,
The recovery of the substance after the rinsing of the test vessels after 48 hours was 34-54% of the initial loading

Reported statistics and error estimates:

NA

Biological results

Time (hour)	Mean measured concentration (mg/L)	Number immobilised per replicate				Total number tested	Total number immobilised	Percentage immobilised (%)
		A	B	C	D
24	Control	0	0	0	0	20	0	0
	Solvent control	0	0	0	0	20	0	0
	0.16	0	0	0	0	20	0	0
	0.44	0	0	0	0	20	0	0
	0.62	0	0	0	0	20	0	0
	1.4	0	0	0	0	20	0	0
	2.1	0	0	0	0	20	0	0
48	Control	0	0	0	0	20	0	0
	Solvent control	0	0	0	0	20	0	0
	0.16	0	0	0	0	20	0	0
	0.44	0	0	0	0	20	0	0
	0.62	0	0	0	0	20	0	0
	1.4	0	0	0	0	20	0	0
	2.1	0	0	0	0	20	0	0

Analytical results

Nominal concentration (mg/L)	Measured concentration of (µg/L)				Mean measured concentration    (mg/L)	Mean measured concentration (%)
	0 hour		48 hour
	(mg/L)	% of nominal	(mg/L)	% of nominal
Control	<LOQ	-	<LOQ	-	<LOQ	-
Solvent control	<LOQ	-	<LOQ	-	<LOQ	-
0.3125	0.11	35	0.20^a	65	0.16	50
0.625	0.55	87	0.34^b	55	0.44	71
1.25	0.85	68	0.39^c	31	0.62	50
2.5	1.8	70	1.0^d	40	1.4	55
5.0	2.6	52	1.7^e	33	2.1	43

All measured concentrations quoted to 2 significant figures

a    Mean of triplicate analyses: 0.61, <LOQ and <LOQ mg/L

b    Mean of triplicate analyses: 0.35, 0.18 and 0.50 mg/L

c    Mean of triplicate analyses: 0.40, 0.27 and 0.52 mg/L

d    Mean of triplicate analyses: 1.0, 1.1 and 1.0 mg/L

e    Mean of triplicate analyses: 1.7, 1.4 and 1.9 mg/L

The limit ofquantification (LOQ)in the study was 0.075 mg/L; <LOQ values treated as 0 when calculating means.

 

Validity criteria fulfilled:

yes

Conclusions:

The EC50 for daphnia is > 2.1 mg/L (measured concentration)

Executive summary:

In a test according to OECD 202, 20 daphnids/concentration were exposed to 0, 0.3125, 0.625, 1.25, 2.5 and 5.0 mg/L of the substance. In the test solutions 0.1 mg/L of the solvent THF was present. No immobility was observed in any of the test vessels during the 48 hour exposure period. Measured concentrations were 0, 0.16, 0.44, 0.62, 1.4 and 2.1 mg/L. The EC50 is > 2.1 mg/L.

Description of key information

In a test according to OECD 202, 20 daphnids/concentration were exposed to 0, 0.3125, 0.625, 1.25, 2.5 and 5.0 mg/L of the substance. In the test solutions 0.1 mg/L of the solvent THF was present. No immobility was observed in any of the test vessels during the 48 hour exposure period. Measured concentrations were 0, 0.16, 0.44, 0.62, 1.4 and 2.1 mg/L. The EC50 is > 2.1 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

2.1 mg/L