Ethyl [2-(4-phenoxyphenoxy)ethyl]carbamate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

04 Sep 1992 to 08 Sep 1992

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPP 72-1 (Fish Acute Toxicity Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Analytical determination of test substance concentration from the definitive test was performed on samples from one of the replicate test vessels of each concentration at the beginning and end of the test. These samples were stored in 125 mL plastic bottles and refrigerated. Samples were transferred to the third party laboratory. Samples were shipped by overnight courier in an ice chest with freezer packs.

Vehicle:

yes

Remarks:

Acetone

Details on test solutions:

A stock with a concentration of 40000 mg/L was prepared by combining 20.4 g of test substance with dilution water in a class A volumetric flask and adjusting the final volume to 500 mL with acetone. The solution was mixed thoroughly. Appropriate amounts of the stock solution were added directly to dilution water by proportional diluter (0.3 mL of stock solution was combined with 3010 mL of water during each diluter cycle = 4 mg/L test substance) and this diluter toxicant cell solution was mixed by a high shear pump with a teflon head. Nominal concentrations of the active ingredient 0 (control), 0.6, 1, 1.6, 2.4 and 4 mg/L.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Age at study initiation: Juvenile

ACCLIMATION
- Acclimation period: 14
- Acclimation conditions (same as test or not): Same as test

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

40 to 48 mg/L CaCO3

Test temperature:

11.5 - 12.9 °C

pH:

7.1 - 7.4

Dissolved oxygen:

8.5 to 9.6 mg/L

Conductivity:

170 - 200 umhos/cm

Nominal and measured concentrations:

Nominal concentrations: 0.6, 1.0, 1.6, 2.4 and 4.0 mg/L
Mean measured concentrations: 0.26, 0.37, 0.58, 0.84, and 1.3 mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel: 20 liter glass aquaria that contained 15 liters of test solution (water depth was approximately 18.5 cm). Test vessels were randomly arranged in a water bath during the 96 hour test (a random numbers table was used to select the location of each vessel).
- Type of flow-through: intermittent-flow proportional diluter
- Renewal rate of test solution: 5.6 media exchanges per 24 h
- 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
- Biomass loading rate: 0.16 g/L

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light, 8 hours dark with 15 minutes transition period
- Light intensity: 37 footcandles

EFFECT PARAMETERS MEASURED:
The number of organisms and the of sublethal effects were determined visually and recorded after 24, 48, 72, and 96 hours

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.66 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95 % CI: 0.60 to 0.72 mg/L

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.26 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Details on results:

- Mortality of control: One hundred percent survival occurred in the control and solvent control and no sublethal effects were noted during the exposure period in either control.
- Other abnormalities: At 24 hours affected fish exhibited erratic swimming, a loss of equilibrium, and lethargy. At 48 hours effected fish were immobilized and on the bottom of the test vessels. At 72 hours affected fish (2 and 4 out of 10) exposed to 0.37 mg/L were dark and lethargic, effected fish (all) exposed to 0.58 mg/L were dark, lethargic, and gasping on the bottom of the test vessel, and effected fish exposed to 0.84 mg/L (all surviving) were immobilized and gasping on the bottom of the test vessel. At 96 hours surviving affected fish were lethargic, exhibiting a loss of equilibrium, and were gasping on the bottom of the test vessel.
- Any observations that might cause a difference between measured and nominal values:
Insoluble material (white particles) was noted in the diluter stock (4.0 mg/L nominal concentration) and in all non-control test vessels the test

Validity criteria fulfilled:

yes

Conclusions:

In an acute aquatic toxicity study performed in accordance with EPA 72-1, exposure of rainbow trout to the test substance resulted in a 96 hour LC50 of 0.66 mg/L with a 95 % confidence interval of 0.60 to 0.72 mg/L (the slope of the dose-response curve = 12.3). The 96 hour no observed effect concentration was 0.26 mg/L

Executive summary:

The acute toxicity of the test substance to the rainbow trout, Oncorhynchus mykiss, was conducted according to the EPA 72-1 guideline and in compliance with GLP. The 96-hour test was performed under flow-through conditions with five concentrations of test substance, a dilution water control, and a solvent control at a of 12 ± 1°C. The dilution water was carbon filtered, dechlorinated tap water collected at and adjusted to a hardness of 40 to 48 mg/L. The test was performed at and above the apparent water solubility of the test substance as evidenced by the observation of white particles in the diluter's toxicant mixing vessel and all non-control test vessels (nominal concentration of the stock solution 4.0 mg/L). Nominal concentrations of the test substance were: 0.6, 1.0, 1.6, 2.4, and 4.0 mg/L. Mean measured concentrations of the test substance in centrifuged test media were: 0.26, 0.37, 0.58, 0.84, and 1.3 mg/L and concentrations were stable during the 96 hour testing period. Mean measured concentrations were used for all calculations. Organisms used in the test were procured from a commercial supplier and acclimated to test conditions for 14 days at the testing facility. After 96 hours of exposure the control organisms had an average weight (blotted dry) of 0.24 g and a mean length of 31 mm. All animals were in good condition at the beginning of the study.

Exposure of rainbow trout to the test substance resulted in a 96-hour median lethal concentration LC50 of 0.66 mg/L, with a 95 % confidence interval of 0.60 to 0.72 mg/L. The 96-hour no observed effect concentration was 0.26 mg/L.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPP 72-1 (Fish Acute Toxicity Test)

GLP compliance:

yes

Test organisms (species):

Lepomis macrochirus

Test type:

flow-through

Water media type:

freshwater

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.74 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Sublethal observations / clinical signs:

The measured concentrations were 0.23, 0.38, 0.56, 0.82 and 1.3 mg/L at test initiation (representing 33-38% of nominal), and 0.34, 0.47, 0.71, 1.0 and 1.6 mg/L at the end of exposure (representing 40-57% of nominal). Endpoints were based on mean measured concentrations, which is acceptable. Water quality parameters (pH, oxygen concentration and temperature) were in accordance with the OECD 203 guideline.

Table 1. The acute toxicity of the test substance to fish

Species	Test type and duration. (purity of test substance)	Actual concentration (as % of nominal)	LC50 in mg/L	NOEC mg/L
Lepomis macrochirus	Flow-through 96 hours (97.8%)	33 - 57	24 h: 1.1(A) 48 h: 1.0(A) 72&96 h: 0.74(A)	24&48 h: 0.64(A) 72&96 h: 0.42(A)

(A) Based on mean measured concentrations

Validity criteria fulfilled:

yes

Conclusions:

In an acute aquatic toxicity test with bluegill sunfish, the 96-hour LC50 was determined to be 0.74 mg/L, based on mean measured concentrations.

Executive summary:

A 96-hour acute toxicity test in bluegill sunfish (Lepomis macrochirus) (2 replicates of ten fish each per concentration) was performed following the EPA 72 -1 guidance and in compliance with GLP. The test was conducted under flow-through conditions with the test substance at nominal test concentrations of 0.6, 1.0, 1.6, 2.4 and 4.0 mg/L, with untreated and solvent-control. Based on the observation of undissolved test material in the test system, samples taken from the test solutions were centrifuged prior to analysis of the test substance. The number of surviving organisms and the occurrence of sublethal effects were determined visually and recorded after 24, 48, 72, and 96 hours.

The measured concentrations were 0.23, 0.38, 0.56, 0.82 and 1.3 mg/L at test initiation (representing 33-38% of nominal), and 0.34, 0.47, 0.71, 1.0 and 1.6 mg/L at the end of exposure (representing 40-57% of nominal). Endpoints were based on mean measured concentrations, which is acceptable. Water quality parameters (pH, oxygen concentration and temperature) were in accordance with the OECD 203 guideline. The 96 -hour LC50 for the test substance in bluegill sunfish was estimated to be 0.74 mg/L.

Reference 3

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 Aug 1992 to 17 Aug 1992

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: US EPA-FIFRA 72-3

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Analytical determination of test substance concentration from the definitive test was performed on samples from one of the replicate test vessels of each concentration at the beginning and end of the test. These samples were stored in 125 mL plastic bottles and refrigerated. Samples were transferred to the third party laboratory. Samples were shipped by overnight courier in an ice chest with freezer packs.

Vehicle:

yes

Remarks:

Acetone

Details on test solutions:

A stock with a concentration of 40000 mg/L was prepared by combining 20.4 g of test substance with dilution water in a class A volumetric flask and adjusting the final volume to 500 mL with acetone. The solution was mixed thoroughly. Appropriate amounts of the stock solution were added directly to dilution water by proportional diluter (0.3 mL of stock solution was combined with 3010 mL of water during each diluter cycle = 4 mg/L test substance) and this diluter toxicant cell solution was mixed by a high shear pump with a teflon head. Nominal concentrations of the active ingredient 0 (control), 0.6, 1, 1.6, 2.4 and 4 mg/L.

Test organisms (species):

Cyprinodon variegatus

Details on test organisms:

TEST ORGANISM
- Common name: Sheepshead minnow
- Age at study initiation: juvenile

ACCLIMATION
- Acclimation period: 14 days
- Acclimation conditions: fish were maintained under flow through conditions in a 270 liter fiberglass tank; acclimation temperature range was 21.9 to 22.5°C and the dissolved oxygen concentration was always at least 7.0 mg/L

Test type:

flow-through

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

22.0 - 22.3 °C

pH:

7.8 - 8.3

Dissolved oxygen:

7.2 - 8.0 mg/L.

Salinity:

1.5 - 1.6 %

Nominal and measured concentrations:

Nominal concentrations: 0.6, 1.0, 1.6, 2.4, and 4.0 mg/L
Mean measured concentrations: 0.26, 0.34, 0.53, 0.90, and 1.2 mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel: 20 liter glass aquaria that contained 15 liters of test solution (water depth was approximately 18 cm). Test vessels were randomly arranged in a water bath during the 96 hour test (a random numbers table was used to select the location of each vessel).
- Type of flow-through: intermittent flow proportional diluter
- Renewal rate of test solution (frequency/flow rate): 5.7 media exchanges per 24 h
- 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
- Biomass loading rate: 0.47 g/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Water used for acclimation of test organisms and for all toxicity testing was carbon filtered, natural salt water adjusted to a salinity of 15 to 16 parts per thousand and stored in polyethylene tanks where it was aerated and recirculated through particle filters, activated carbon, and an ultraviolet sterilizer

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light and 8 hours dark
- Light intensity: 32 footcandles

EFFECT PARAMETERS MEASURED:
The number of surviving organisms and the occurrence of sublethal effects were determined visually and after 24, 48, 72, and 96 hours.

TEST CONCENTRATIONS
Range finding study:
- Test concentrations: Nominal concentrations of the test substance were 0.01, 0.1, 1.0, and 10.0 mg/L
- Results used to determine the conditions for the definitive study: After 96 hours there was 0% survival at 10 mg/L and survival at all lower tested concentrations.

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

1.1 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95 % confidence interval of 0.90 to 1.2 mg/L (the slope of the dose-response curve could not be calculated from this data set)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.53 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Details on results:

- Mortality of control: One hundred percent survival occurred in the control and solvent control and no sublethal effects were noted during the exposure period in either control.
- Other abnormalities: At 24 hours affected fish were lethargic and exhibiting a loss of equilibrium (in addition, fish exposed to 1.3 mg/L were swimming erratically). At 48, 72, and 96 hours affected fish were lethargic, exhibiting a loss of equilibrium and swimming erratically.
- Any observations that might cause a difference between measured and nominal values: Insoluble material (white particles) was noted in the diluter stock (4.0 mg/L nominal concentration) and on the bottom of all non-control test vessels throughout the test.

Sublethal observations / clinical signs:

Table 1. Measured concentration of test substance in centrifuged test media during the toxicity test with the test substance and the sheepshead minnow, Cyprinodon variegatus.

Nominal Concentration (mg/L)	Measured concentration (mg/L)	Measured concentration (mg/L)	Measured concentration (mg/L)
	0 hour	96 hour	mean
0.0 (control)	ND	ND	ND
0.0 (solvent control)	ND	ND	ND
0.6	0.20	0.31	0.26
1.0	0.30	0.39	0.34
1.6	0.46	0.60	0.53
2.4	0.80	1.0	0.90
4.0	1.2	1.2	1.2
40000 (primary stock in acetone)	40200	41400	40800

Note: ND = none detected at the analytical detection limit of 0.02 mg/L.

 

Table 2. Survival of sublethal effect data from the toxicity test with the test substance and thesheepshead minnow, Cyprinodon variegatus.

Mean measured concentration (mg/L)	Rep.	Number alive	Number alive	Number alive	Number alive	Number alive	Number effected	Number effected	Number effected	Number effected	Number effected
		0 hr	24 hr	48 hr	72 hr	96 hr	0 hr	24 hr	48 hr	72 hr	96 hr
ND (control)	1	10	10	10	10	10	0	0	0	0	0
	2	10	10	10	10	10	0	0	0	0	0
ND (solvent control)	1	10	10	10	10	10	0	0	0	0	0
	2	10	10	10	10	10	0	0	0	0	0
0.26	1	10	10	10	10	10	0	0	0	0	0
	2	10	10	10	10	10	0	0	0	0	0
0.34	1	10	10	10	10	10	0	0	0	0	0
	2	10	10	10	10	10	0	0	0	0	0
0.53	1	10	10	10	10	10	0	0	0	0	0
	2	10	10	10	10	10	0	0	0	0	0
0.90	1	10	10	10	10	10	0	10	10	10	10
	2	10	10	10	10	10	0	10	10	10	10
1.2	1	10	9	7	4	3	0	9	7	4	3
	2	10	9	8	4	2	0	9	8	4	2

Note:

ND = none detected at the analytical detection limit of 0.02 mg/L

At 24 hours effected fish were lethargic and exhibiting a loss of equilibrium (in addition to fish exposed to 1.3mg/L were swimming erratically). At 48, 72 and 96 hours effected fish were lethargic, exhibiting a loss of equilibrium and swimming erratically.

Validity criteria fulfilled:

yes

Conclusions:

In an acute aquatic toxicity study perfoemd in accordance with EPA 72-3, exposure of sheepshead minnow to the test substance resulted in a 96 hour LC50 of 1.1 mg/L with a 95 % confidence interval of 0.90 to 1.2 mg/L (the slope of the dose-response curve could not be calculated from this data set). The 96 hour no observed effect concentration was 0.53 mg/L.

Executive summary:

The acute toxicity of the test substance to the Sheepshead minnow, Cyprinodon variegatus was conducted following the EPA 72 -3 guidance and in compliance with GLP. The test was performed under flow-through conditions with five concentrations of test substance, a dilution water control, and a solvent control at a temperature of 22 ± 1°C. The dilution water was filtered natural sea water adjusted to a salinity of 15 to 16 parts per thousand. The test was performed at and above the apparent water solubility of the test substance, as evidenced by the observation of particles floating on the water surface in the diluter's toxicant mixing vessel and all non-control test vessels (nominal concentration of the stock solution was 4.0 mg/L). Nominal concentrations of the test substance were: 0.6, 1.0, 1.6, 2.4, and 4.0 mg/L. Mean measured concentrations of the test substance in centrifuged test media were: 0.26, 0.53, 0.90, and 1.2 mg/L and concentrations were stable during the 96 hour testing period. Mean measured concentrations were used for all calculations. Organisms used in the test procured from a commercial supplier and acclimated to test conditions for 14 days at the test facility. After 96 hours of exposure the control organisms had an average wet weight (blotted dry) of 0.71 g and a mean length of 34 mm. All animals were in good condition at the beginning of the study.

Exposure of Sheepshead minnows to the test substance resulted in a 96 hour median lethal concentration (LC50) of 1.1 mg/L test substance, with a 95% confidence interval of 0.90 to 1.2 mg/L. The 96 hour no observed effect concentration was 0.53 mg/L.

Reference 4

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

GLP compliance:

yes

Test organisms (species):

Cyprinus carpio

Test type:

flow-through

Water media type:

freshwater

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

1.5 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Sublethal observations / clinical signs:

The measured concentrations were 0.26, 0.40, 0.62, 0.93 and 1.4 mg/L at test initiation (representing 35- 43% of nominal), and 0.32, 0.52, 0.75, 1.2 and 1.7 mg/L at the end of exposure (representing 43-53% of nominal). Endpoints were based on mean measured concentrations, which is acceptable. Water quality parameters (pH, oxygen concentration and temperature) were essentially in accordance with the OECD 203 guideline.

Table 1. The acute toxicity of the test substance to fish

Species	Test type and duration. (purity of test substance)	Actual concentration (as % of nominal)	LC50 in mg/L	NOEC mg/L
Cyprinus carpio	Flow-through 96 hours (97.8%)	35 - 53	24-96 h: 1.5(A)	24 h: 0.46(A) 48-96 h: 0.68(A)

(A) Based on mean measured concentrations

Validity criteria fulfilled:

yes

Conclusions:

In an acute aquatic toxicity study in carp, performed in accordance with OECD TG 203, the 96-hour LC50 was 1.5 mg/L, based on mean measured concentrations.

Executive summary:

A 96-hour acute toxicity test in carp (Cyprinus carpio) (2 replicates of ten fish each per concentration) was performed following the OECD TG 203 and in compliance with GLP. The test was conducted under flow-through conditions with the test substance at nominal test concentrations of 0.6, 1.0, 1.6, 2.4 and 4.0 mg/L, with untreated and solvent-control. Based on the observation of undissolved test material in the test system, samples taken from the test solutions were centrifuged prior to analysis of the test substance. The number of surviving organisms and the occurrence of sublethal effects were determined visually and recorded after 24, 48, 72, and 96 hours.

The measured concentrations were 0.26, 0.40, 0.62, 0.93 and 1.4 mg/L at test initiation (representing 35- 43% of nominal), and 0.32, 0.52, 0.75, 1.2 and 1.7 mg/L at the end of exposure (representing 43-53% of nominal). Endpoints were based on mean measured concentrations, which is acceptable. Water quality parameters (pH, oxygen concentration and temperature) were essentially in accordance with the OECD 203 guideline. The 96-h LC50 of the test substance in carp was estimated to be 1.5 mg/L.

Reference 5

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

GLP compliance:

yes

Test organisms (species):

Ictalurus punctatus

Test type:

flow-through

Water media type:

freshwater

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.88 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Sublethal observations / clinical signs:

The measured concentrations were 0.26, 0.42, 0.63, 0.93 and 1.52 mg/L at test initiation (representing 38-43% of nominal), and 0.41, 0.56, 0.91, 1.1 and 1.7 mg/L at the end of exposure (representing 43-68% of nominal). Endpoints were based on mean measured concentrations, which is acceptable. Water quality parameters (pH, oxygen concentration and temperature) were according to the OECD 203 guideline.

Table 1. The acute toxicity of the test substance to fish

Species	Test type and duration. (purity of test substance)	Actual concentration (as % of nominal)	LC50 in mg/L	NOEC mg/L
Ictalurus punctatus	Flow-through 96 hours (97.8%)	38 - 68	24 h: 0.94(A) 48 h: 0.89(A) 72-96 h: 0.88(A)	24 h: 0.77(A) 48-96 h: 0.49(A)

(A) Based on mean measured concentrations

Validity criteria fulfilled:

yes

Conclusions:

In an acute aquatic toxicity test with the test substance in channel catfish, performed in accordance with OECD TG 203, the 96-hour LC50 was 0.88 mg/L, based on mean measured concentrations.

Executive summary:

A 96-hour acute toxicity test in channel catfish (Ictalurus punctatus) (2 replicates of ten fish each per concentration) performed following the OECD TG 203 and in compliance with GLP was conducted under flow-through conditions with the test substance at nominal test concentrations of 0.6, 1.0, 1.6, 2.4 and 4.0 mg/L, with untreated and solvent-control. Based on the observation of undissolved test material in the test system, samples taken from the test solutions were centrifuged prior to analysis of the test substance. The number of surviving organisms and the occurrence of sublethal effects were determined visually and recorded after 24, 48, 72 and 96 hours.

The measured concentrations were 0.26, 0.42, 0.63, 0.93 and 1.52 mg/L at test initiation (representing 38-43% of nominal), and 0.41, 0.56, 0.91, 1.1 and 1.7 mg/L at the end of exposure (representing 43-68% of nominal). Endpoints were based on mean measured concentrations, which is acceptable. Water quality parameters (pH, oxygen concentration and temperature) were according to the OECD 203 guideline.

The 96-hour LC50 for the test substance in Ictalurus punctatus was 0.88 mg/L, based on mean measured concentrations.

Description of key information

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

Freshwater, 96-h LC50 = 0.66 mg/L, flow-through, Oncorhynchus mykiss, mortality, EPA 72 -1, Ward 1993a

Marine water, 96-h LC50 = 1.1 mg/L, flow-through, Cyprinodon variegatus, mortality, EPA 72 -1, Ward 1993b

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

0.66 mg/L

Marine water fish

Marine water fish

Dose descriptor:

LC50

Effect concentration:

1.1 mg/L

Additional information

Freshwater, EPA 72 -1, Ward 1993a, rainbow trout

The acute toxicity of the test substance to the rainbow trout, Oncorhynchus mykiss, was conducted according to the EPA 72-1 guideline and in compliance with GLP. The 96-hour test was performed under flow-through conditions with five concentrations of test substance, a dilution water control, and a solvent control at a of 12 ± 1°C. The dilution water was carbon filtered, dechlorinated tap water collected at and adjusted to a hardness of 40 to 48 mg/L. The test was performed at and above the apparent water solubility of the test substance as evidenced by the observation of white particles in the diluter's toxicant mixing vessel and all non-control test vessels (nominal concentration of the stock solution 4.0 mg/L). Nominal concentrations of the test substance were: 0.6, 1.0, 1.6, 2.4, and 4.0 mg/L. Mean measured concentrations of the test substance in centrifuged test media were: 0.26, 0.37, 0.58, 0.84, and 1.3 mg/L and concentrations were stable during the 96 hour testing period. Mean measured concentrations were used for all calculations. Organisms used in the test were procured from a commercial supplier and acclimated to test conditions for 14 days at the testing facility. After 96 hours of exposure the control organisms had an average weight (blotted dry) of 0.24 g and a mean length of 31 mm. All animals were in good condition at the beginning of the study.

Exposure of rainbow trout to the test substance resulted in a 96-hour median lethal concentration LC50 of 0.66 mg/L, with a 95 % confidence interval of 0.60 to 0.72 mg/L. The 96-hour no observed effect concentration was 0.26 mg/L

Marine water, EPA 72 -3, Ward 1993b, sheepshead minnow

The acute toxicity of the test substance to the Sheepshead minnow, Cyprinodon variegatus was conducted following the EPA 72 -3 guidance and in compliance with GLP. The test was performed under flow-through conditions with five concentrations of test substance, a dilution water control, and a solvent control at a temperature of 22 ± 1°C. The dilution water was filtered natural sea water adjusted to a salinity of 15 to 16 parts per thousand. The test was performed at and above the apparent water solubility of the test substance, as evidenced by the observation of particles floating on the water surface in the diluter's toxicant mixing vessel and all non-control test vessels (nominal concentration of the stock solution was 4.0 mg/L). Nominal concentrations of the test substance were: 0.6, 1.0, 1.6, 2.4, and 4.0 mg/L. Mean measured concentrations of the test substance in centrifuged test media were: 0.26, 0.34, 0.53, 0.90, and 1.2 mg/L and concentrations were stable during the 96 hour testing period. Mean measured concentrations were used for all calculations. Organisms used in the test procured from a commercial supplier and acclimated to test conditions for 14 days at the test facility. After 96 hours of exposure the control organisms had an average wet weight (blotted dry) of 0.71 g and a mean length of 34 mm. All animals were in good condition at the beginning of the study.

Exposure of Sheepshead minnows to the test substance resulted in a 96 hour median lethal concentration (LC50) of 1.1 mg/L test substance, with a 95% confidence interval of 0.90 to 1.2 mg/L. The 96 hour no observed effect concentration was 0.53 mg/L.

Supporting studies

EPA 72 -1, Ward 1993c, bluegill sunfish

A 96-hour acute toxicity test in bluegill sunfish (Lepomis macrochirus) (2 replicates of ten fish each per concentration) was performed following the EPA 72 -1 guidance and in compliance with GLP. The test was conducted under flow-through conditions with the test substance at nominal test concentrations of 0.6, 1.0, 1.6, 2.4 and 4.0 mg/L, with untreated and solvent-control. Based on the observation of undissolved test material in the test system, samples taken from the test solutions were centrifuged prior to analysis of the test substance. The number of surviving organisms and the occurrence of sublethal effects were determined visually and recorded after 24, 48, 72, and 96 hours.

The measured concentrations were 0.23, 0.38, 0.56, 0.82 and 1.3 mg/L at test initiation (representing 33-38% of nominal), and 0.34, 0.47, 0.71, 1.0 and 1.6 mg/L at the end of exposure (representing 40-57% of nominal). Endpoints were based on mean measured concentrations. Water quality parameters (pH, oxygen concentration and temperature) were in accordance with the OECD 203 guideline. The 96 -hour LC50 for the test substance in bluegill sunfish was estimated to be 0.74 mg/L.

OECD TG 203, Ward 1993d, carp

A 96-hour acute toxicity test in carp (Cyprinus carpio) (2 replicates of ten fish each per concentration) was performed following the OECD TG 203 and in compliance with GLP. The test was conducted under flow-through conditions with the test substance at nominal test concentrations of 0.6, 1.0, 1.6, 2.4 and 4.0 mg/L, with untreated and solvent-control. Based on the observation of undissolved test material in the test system, samples taken from the test solutions were centrifuged prior to analysis of the test substance. The number of surviving organisms and the occurrence of sublethal effects were determined visually and recorded after 24, 48, 72, and 96 hours.

The measured concentrations were 0.26, 0.40, 0.62, 0.93 and 1.4 mg/L at test initiation (representing 35- 43% of nominal), and 0.32, 0.52, 0.75, 1.2 and 1.7 mg/L at the end of exposure (representing 43-53% of nominal). Endpoints were based on mean measured concentrations. Water quality parameters (pH, oxygen concentration and temperature) were essentially in accordance with the OECD 203 guideline. The 96-h LC50 of the test substance in carp was estimated to be 1.5 mg/L.

OECD TG 203, Ward 1993e, channel catfish

A 96-hour acute toxicity test in channel catfish (Ictalurus punctatus) (2 replicates of ten fish each per concentration) performed following the OECD TG 203 and in compliance with GLP was conducted under flow-through conditions with the test substance at nominal test concentrations of 0.6, 1.0, 1.6, 2.4 and 4.0 mg/L, with untreated and solvent-control. Based on the observation of undissolved test material in the test system, samples taken from the test solutions were centrifuged prior to analysis of the test substance. The number of surviving organisms and the occurrence of sublethal effects were determined visually and recorded after 24, 48, 72 and 96 hours.

The measured concentrations were 0.26, 0.42, 0.63, 0.93 and 1.52 mg/L at test initiation (representing 38-43% of nominal), and 0.41, 0.56, 0.91, 1.1 and 1.7 mg/L at the end of exposure (representing 43-68% of nominal). Endpoints were based on mean measured concentrations. Water quality parameters (pH, oxygen concentration and temperature) were according to the OECD 203 guideline.

The 96-hour LC50 for the test substance in Ictalurus punctatus was 0.88 mg/L, based on mean measured concentrations.