Allyl phenoxyacetate

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:

10 - 12 Jan 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)

Remarks:

Staatliches Gewerbeaufsichtsamt Hildesheim, Niedersachsen, Germany

Analytical monitoring:

yes

Details on sampling:

- Concentrations and sampling method: all concentrations were analytically verified at the start of the exposure and at renewal (0 and 24 h) and in 24 h old media at renewal and at the end of the test (24 and 48 h).
- Sample storage conditions before analysis: all samples were stored at 6 ± 2 °C until the start of the analysis, if necessary

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: a stock solution was freshly prepared with dilution water prior to the start of the exposure and the water renewal (24 h). 10.0 mg/L of the test item were weighed directly into the dilution water and the solution was mixed thoroughly by manual agitation. The 5 test item concentrations were prepared by dilution of the stock solution with dilution water.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain/clone: clone 5
- Source: bred at the test facility
- Age of the daphnids at the start of the exposure: < 24 h, juvenile daphnids were removed from the culture vessels at the latest 24 hours before the start of the exposure. the juveniles born within the following period of max. 24 hours preceding the exposure were used for the test.
- Feeding during test: no

CULTURING:
- Culturing medium: Elendt M4
- Culturing conditions: in glass vessels (2 - 3 L capacity) with approx. 1.8 L culture medium, at 20 ± 2 °C, in an incubator, 16 h illumination, light intensity of max. 1500 Lux
- Type and amount of food: ad libitum with a mix of unicellular green algae, e.g. Pseudokirchneriella subcapitata and Desmodesmus subspicatus, with an algae cell density of > 106cells/mL.
- Feeding frequency: at least 5 times per week

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

169 to 177 mg CaC03/L (dilution water)

Test temperature:

18-22 °C

pH:

7.46 - 8.15

Dissolved oxygen:

7.19 - 9.28 mg/L

Conductivity:

410 - 420 µS/cm (dilution water)

Nominal and measured concentrations:

Nominal: Control, 0.625, 1.25, 2.50, 5.00 and 10.0 mg/L
Geom. mean measured: < LOQ, 0.323, 0.72, 1.56, 2.66 and 6.91 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 mL glass beakers
- Type: beakers loosely covered with watch glasses
- Test volume: 20 mL
- Aeration: no
- Renewal rate of test solution (frequency/flow rate): 24 h (a second set of test vessels was filled with the freshly prepared test solutions and the daphnids were transferred by pipette)
- 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: dilution water, according to guideline
- Culture medium different from test medium: no
- Intervals of water quality measurement: at the start of the exposure and at renewal (24 h), the water quality parameters of the fresh media (pH, dissolved oxygen concentration) were measured in one additional replicate (without daphnids) per concentration level and control. The water quality parameters of the old media (24 and 48 h), were measured in all replicates (containing daphnids) per concentration level and control.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16/8 hours light/dark cycle
- Light intensity: diffuse light, light intensity of max. 1500 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : the percentage of immobility, was determined in all test item concentrations and in the control after 24 and 48 h of exposure.

VEHICLE CONTROL PERFORMED: no

RANGE-FINDING STUDY
- Test concentrations: 1, 10 and 100 mg/L test item were tested
- Results used to determine the conditions for the definitive study: the test concentrations were selected based on the results of a non- GLP preliminary range finding test. Immobilization was recorded in all tested concentrations (10%, 100%, 100% at 1, 10 and 100 mg/L test concentration after 48 h respectively).

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

2.07 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CI 1.56 - > 6.91

Details on results:

- Mortality of control: no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: all tested concentration levels were visually clear throughout the exposure.

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Relevant effect levels: EC50 (24 h) = 1.92 mg/L (95% CI: 1.09-3.32 mg/L)
- Other: test conducted at 12 to 13-01-2017

BIOLOGICAL RESULTS

Table 1: Immobilization Rates after 24 and 48 h of Exposure in the Definitive Test

		IMMOBILIZATION [%]
Nominal test item concentration [mg/L]	Geometric mean measured test item concentration [mg/L]	24h					48h
		Replicates
		1	2	3	4	MV	1	2	3	4	MV
10	6.91	80	100	40	60	70	100	100	80	100	95
5	2.66	0	0	0	0	0	80	80	80	80	80
2.5	1.56	0	0	0	0	0	0	0	0	0	0
1.25	0.72	0	0	0	0	0	0	0	0	0	0
0.625	0.323	0	0	0	0	0	0	0	0	0	0
control	control	0	0	0	0	0	0	0	0	0	0

ANALYTICAL RESULTS

The measured concentrations of the test item in fresh media at the start of the exposure and at renewal (0 and 24 hours) were in the range of 80 to 100% of the nominal values and 18 to 66% in old media at renewal and at the end of the test (24 and 48 hours). However, at the lowest concentration level of 0.625 mg/L (nominal), the measured concentrations of the test item were below the LOQ (= 0.4 mg/L) in old media at renewal and at the end of the test (24 and 48 hours).

Table 2: Measured Concentrations and Percent of Nominal Concentration of the Test Item

Sampling date	Start of the exposure interval 0 h		End of the exposure interval 24 h		Start of the exposure interval 24 h		End of the exposure interval 48 h
Nominal test item concentration [mg/L]	Meas.conc. [mg/L]	%	Meas. conc. [mg/L]	%	Meas. conc. [mg/L]	%	Meas. conc. [mg/L]	%	Geometric mean measured test item concentrations* [mg/L]
10	10	100	6.62	66	9.61	96	3.59	36	6.91
5	4.45	89	3.15	63	4	80	0.897	18	2.66
2.5	2.31	93	1.34	54	2.04	82	0.933	37	1.56
1.25	1.17	93	0.486	39	1.01	81	0.467	37	0.72
0.625	0.54	86	< LOQ		0.503	80	< LOQ		0.323
control	< LOQ	< LOQ	< LOQ	< LOQ	< LOQ	< LOQ	< LOQ	< LOQ

LOQ: limit of quantification of the analytical method (0.4 mg/L of the test item)

* : Measured concentrations < LOQ were taken into account with half of the LOQ (= 0.2 mg/L).

Validity criteria fulfilled:

yes

Conclusions:

The study according to OECD 202 and GLP resulted in an EC50 (48 h) value of 2.07 mg/L (geom. mean meas.).

Executive summary:

The study was performed according to OECD guideline 202 and GLP. The water flea, Daphnia magna was exposed to nominal test item concentrations of 0 (control), 0.625, 1.25, 2.50, 5.00 and 10.0 mg/L (geom. mean meas.: < LOQ, 0.323, 0.72, 1.56, 2.66 and 6.91 mg/L) for 48 h. These concentrations were chosen based on the results of a range finding test with test item concentrations of 1, 10 and 100 mg/L. The definitive test was performed in a semi-static freshwater system. The medium was freshly prepared and replaced once after 24 h. Potassium dichromate was used as a reference substance. The test item was monitored during the test by sample analysis via HPLC-DAD. The recoveries of the test item were between 80 and 100% in freshly prepared media (0 and 24 h) and between 18 to 66% in the old media (after 24 h incubation). Therefore, effect values are expressed as geom. mean measured concentrations. The test item caused biological effects to Daphnia magna and resulted in an EC50 (48 h) of 2.07 mg/L (geom. mean meas.).

Description of key information

EC50 (48 h) = 2.07 mg/L (geom. mean meas., D. magna, OECD 202) 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

2.07 mg/L

Additional information

One study was performed according to OECD guideline 202 and GLP. The water flea, Daphnia magna was exposed to nominal test item concentrations of 0 (control), 0.625, 1.25, 2.50, 5.00 and 10.0 mg/L (geom. mean meas.: < LOQ, 0.323, 0.72, 1.56, 2.66 and 6.91 mg/L) for 48 h. These concentrations were chosen based on the results of a range finding test with test item concentrations of 1, 10 and 100 mg/L. The definitive test was performed in a semi-static freshwater system. The medium was freshly prepared and replaced once after 24 h. Potassium dichromate was used as a reference substance. The test item was monitored during the test by sample analysis via HPLC-DAD. The recoveries of the test item were between 80 and 100% in freshly prepared media (0 and 24 h) and between 18 to 66% in the old media (after 24 h incubation). Therefore, effect values are expressed as geom. mean measured concentrations. The test item caused biological effects to Daphnia magna and resulted in an EC50 (48 h) of 2.07 mg/L (geom. mean meas.).