N-[2,5-dichloro-4-(1,1,2,3,3,3-hexafluoropropoxy)-phenyl-aminocarbonyl]-2,6-difluorobenzamide

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 Jul 1986 to 03 Oct 1986

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

according to guideline

Guideline:

other: US EPA Guideline EG-1

Version / remarks:

1982

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Samples for analysis were taken after 0 h and 48 h exposure.

Vehicle:

yes

Remarks:

DMF and Alkylphenol-polyglycolether

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Stock solution: 100 mg of the test substance were dissolved in DMF (approx. 8 ml), 40 mg Alkylphenol-polyglycolether and made up to 10 mL with DMF

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Strain/clone: Daphnia magna straus 1820
- Age at study initiation (mean and range, SD): young daphnia (0-24h old)
- Method of breeding: Parthenogenic reproduction. 100-200 adults were held for breeding in 3000 mL beakers with 2000 mL reconstituted water. Feed: 5 times per week with a suspension of green algae supplemented by trout chow and/or powder milk and/or yeast; in such quantities that food is consumed after 24 hours
- Pretreatment: 24 hours before the start of the test reproductive daphnia are seperated from the young by sieving through a 800 micrometer sieve. This operation is repeated immediatley before the start and the young daphnia (0-24 h old) are retained for the test

ACCLIMATION
- Acclimation period: None. Breeding conditions were equal to test conditions.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

240 mg CaCO3/L

Test temperature:

20 ± 1 °C

pH:

7.8 - 8.0

Dissolved oxygen:

8.1 - 8.3 mg O2/L

Nominal and measured concentrations:

Nominal: 0.0016, 0.0031, 0.0063, 0.00125, 0.00250, 0.00500 and 0.0100 mg/L
Measured: <0.003, <0.003, <0.004, 0.007, 0.0022, 0.0028 and 0.0055 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL beakers covered with watch glasses
- Aeration: None
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- No. of vessels per vehicle control (replicates): 2


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted water produced by dissolving: 65 mg NaHCO3, 294 mg CaCl2 2H2O, 123 mg MgSO4 and 6mg KCL in 1000 mL bidistilled water. The water was aerated with clean air for ar least 24 h before use.

OTHER TEST CONDITIONS
- Light intensity: 16 hours fluorescent light daily, < 800 lux

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

1.1 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

The measured concentrations were not in close agreement (46-100%) with the nominal concentrations both at the beginning and at the end of the test. Therefore the results are based on nominal concentrations of the test substance.

Table 1. Toxicity of the test substance to Daphnia magna - percentage immobilised

Actual concentration (mg/L)	% immobilised
	24 hours	48 hours
Control	0	0
Vehicle control	0	0
<0.0003	0	5
<0.0003	5	10
<0.0004	10	90
0.0007	30	70
0.0022	30	70
0.0028	30	80
0.0055	25	100

Conclusions:

In an acute toxicity test with Daphnia magna, performed in accordance with EPA EG-1 guideline, the 48-hour EC50 of the test substance was determined to be 1.1 µg/L.

Executive summary:

The acute toxicity of the test substance to Daphnia magna was determined in the study performed following the EPA EG-1 guideline and in compliance with GLP principles. The test was performed under static conditions in freshwater with the following seven concentrations: 0.00016, 0.00031, 0.00063, 0.00125, 0.00250, 0.00500 and 0.01000 mg/L (nominal). Two control groups of animals were included: One control group was exposed to dilution water only and in the second control was the vehicle control group exposed to the solvent (DMF and Alkylphenol-polyglycolether). Ten Daphnia magna were loaded into each of 2 replicate test vessels per treatment. To check the concentrations of the test substance, high performance liquid chromatography was used at 0 and 48 hours. Daphnia magna were assessed for toxic effects at 3, 6, 24 and 48 hours. The EC50 values were calculated according to J. BERKSON, JASA 48 (1953), 569-599.

Results showed that the measured concentrations were not in close agreement (46-100%) with the nominal concentrations both at the beginning and at the end of the test. Therefore the results are based on nominal concentrations of the test substance. The 48-hour EC50 was determined to be 1.1 µg/L.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

30 Jan 1987 to 3 Feb 1987

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPP 72-3 (Estuarine/Marine Fish, Mollusk, or Shrimp Acute Toxicity Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Sampling method: Seawater samples were extracted with methylene chloride (organic solvent). The methylene chloride extract was dried through sodium sulfate and rotary evaporated. The remaining residue was quantitatively transferred to vials containing scintillation cocktail for analysis by liquid scintillation counting.

Vehicle:

yes

Remarks:

acetone

Test organisms (species):

Americamysis bahia (previous name: Mysidopsis bahia)

Details on test organisms:

TEST ORGANISM
- Common name: Mysid shrimp
- Age at study initiation (mean and range, SD): ≤ 24 hours old
- Feeding during test: Mysids were fed live brine shrimp nauplii twice daily and the soil nematode (Panagrellus redivivus) three times weekly.

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

25 ± 1 °C

pH:

8.0

Dissolved oxygen:

> 90% at test initation

Salinity:

32 ‰

Nominal and measured concentrations:

Nominal concentrations: 0.080, 0.13, 0.22, 0.36, 0.60 and 1.0 µg/L.
Measured concentrations: 0.021, 0.035, 0.073, 0.17, 0.30 and 0.83 µg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 1.6L glass vessels
- Volume of solution: 800 mL
- No. of organisms per vessel: 10 mysids per replicate
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- No. of vessels per vehicle control (replicates): 1

OTHER TEST CONDITIONS
- Adjustment of pH: 8.0
- Photoperiod: 16 hours of light and 8 hours of darkness
- Light intensity: 70-90 footcandles

VEHICLE CONTROL PERFORMED: yes

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.042 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

Tables with the nominal and measured concentrations, as well as with the LC50 values, 95% confidence intervals, and no observed effect concentration for mysid shrimp exposed to the test substance are available in 'Any other information on results incl. tables'.

Table 1. Nominal and measured (0 -hour analysis) test concentration during the exposure of mysid shrimp to the test substance

Nominal concentration (µg/L)	Measured concentration (µg/L)	Recovery (%)
Control	<0.0043	-
Solvent control	<0.0043	-
0.08	0.021	26
0.13	0.035	27
0.22	0.073	33
0.36	0.17	47
0.36	0.18	50
0.6	0.3	50
1	0.83	83

Table 2. The LC50 values, 95% confidence intervals, and no observed effect concentration for mysid shrimp exposed to the test substance

		Confidence limits
LC50 (µg/L)		Lower (µg/L)	Upper (µg/L)
24-hour	>0.30	-	-
48- hour	0.12	0.092	0.16
72- hour	0.049	0.038	0.061
96- hour	0.042	0.036	0.051

LC50: Based on measured (0 -hour analysis) test concentrations

Validity criteria fulfilled:

yes

Conclusions:

In an acute toxicity study in mysid shrimp (Mysidopsis bahia) performed in accordance with EPA 72-3, the 96-hour LC50 was determined to be 0.042 µg/L.

Executive summary:

The purpose of this study was to estimate the acute toxicity of 14C-test substance to mysid shrimp (Americamysis bahia) under static conditions according to EPA 72-3. A 96 hour exposure was conducted in this study with nominal concentrations of 0.080, 0.13, 0.22, 0.36, 0.60 and 1.0 µg/L and measured concentrations of 0.021, 0.035, 0.073, 0.17, 0.30 and 0.83 µg/L, respectively. Ten mysides (< 24 hours old) per replicate (2 replicates/control and treatment groups, 1 replicate/vehicle control) were tested at 25 ± 1 °C and 32 ‰ salinity level. Results showed that the 96-hour LC50 was 0.042 µg/L. The no observed effect concentration was < 0.021 µg/L. The water quality parameters remained within acceptable limits througout the exposure period for survival of mysid shrimp.

Description of key information

All available data was assessed and the studies representing the worst-case effects are included here as key studies. The results can be considered worst-case and are selected for the CSA. Other studies are included as supporting information.

Freshwater 48-h EC50 = 1.1 µg/L, static, Daphnia magna, immobility, EPA EG-1, Rufli 1986

Marine water, 96-h LC50 = 0.042 µg/L, static, Americamysis bahia, mortality, EPA 72-3, Suprenant 1987

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

1.1 µg/L

Marine water invertebrates

Marine water invertebrates

Dose descriptor:

LC50

Effect concentration:

0.042 µg/L

Additional information

There are five standard guidelines and GLP-compliant studies available for this endpoint. All these studies followed EPA 72-2, EPA 72-3, EPA EG-1 or OECD TG 235 guidelines. The 48-h study on Daphnia (Rufli 1986, Reliability 2) and 96-h study on mysid shrimp (Suprenant 1987, Reliability 1) were selected as key studies because they represent the worst-case effects (i.e. showed the lowest E(L)C50 value) for freshwater and marine water conditions, respectively. Daphnia magna was exposed to the test substance under static condition at concentrations of 0.00016, 0.00031, 0.00063, 0.00125, 0.00250, 0.00500 and 0.01000 mg/L (nominal). One blank control group was exposed to dilution water only, and one vehicle control group was exposed to the solvent (DMF and Alkylphenol-polyglycolether). Ten Daphnia magna were loaded into each of 2 replicate test vessels per treatment. The 48-hour EC50 was determined to be 0.0011 mg/L (based on mean measured concentration). The marine shrimp, Americamysis bahia, was exposed under static conditions to 0.080, 0.13, 0.22, 0.36, 0.60 and 1.0 µg/L 14C-labelled test substance (initial measured concentrations of 0.021, 0.035, 0.073, 0.17, 0.30 and 0.83 µg/L, respectively) for 96 hours. Ten mysids per replicate (2 replicates/blank control and treatment groups, 1 replicate/vehicle control) were tested at 25 ± 1 °C and 32 ‰ salinity level. The LC50 was determined to be 0.042 µg/L, based on initial measured concentrations.

The other three studies (two studies on Daphnia magna and one study on Chironomus riparius) are included as supporting studies. In the Daphnia magna studies, the test organisms were exposed to 14C-labelled test substance for 48 hours. The EC50 value was determined to be 0.0013 mg/L (nominal) in a no sediment included study (Forbis 1986a; Reliability 1) and was determined to be 0.004 mg/L (nominal) in a sediment-included study, whereas a decrease in test substance concentration in the water phase was observed. After 48 hours, 60 – 88% of the nominal concentration was found in the sediment phase (Forbis 1986b; Reliability 1). In the Chironomus riparius study (Bradley 2022; Reliability 1), the test organisms were exposed to nominal concentrations of 2.0, 4.0, 8.0, 16, and 32 μg/L for 48 hours (corresponded to geometric mean measured concentrations of 1.6, 3.0, 6.2, 12, and 21 μg/L, respectively). The 48-hour EC50 value was determined to be 10 μg/L, based on geometric mean measured concentrations.

Metabolite - available information

Two 48-hour toxicity studies on Daphnia magna are available with the major degradation products (i.e. M4 and M6). As the dossier has been prepared to address the test substance itself, these studies are not summarised as endpoint study records but are briefly discussed here. Both studies followed EPA 72-2 guideline or OECD TG 202, and compliant with GLP. The EC50 value for M4 was determined to be 2.6 mg/L (Grade 2001). The EC50 value for M6 was determined to be 0.88 mg/L in the original report (Grade 1994). This EC50 was later recalculated outside of the original study and determined to be 0.95 mg/L.